Draft for Public Comment

Number SR 50-1:2010

Title Code of practice for building services – Part 1: Domestic plumbing & heating

This document specifies the requirements for the design, installation, commissioning & maintenance of plumbing and heating systems for domestic buildings.

Enquiry period: 28th May 2010 to 27th August 2010

Readers are warned that this draft is subject to ongoing development and change

Please send your comments on the comments sheet available on www.NSAI.ie to: gay.moran@nsai.ie or

NSAI 1 Swift Square, Northwood, Santry Dublin 9

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NSAI/TC 31 Building Services Commitee Date: 2010-05

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Code of practice for building services — Part 1 — Domestic plumbing and heating

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Contents Page

Foreword ............................................................................................................................................................. 7

Introduction ........................................................................................................................................................ 7

1 Scope ..................................................................................................................................................... 8

2 Normative references ........................................................................................................................... 8

3 Terms and definitions......................................................................................................................... 11

4 Cold water supply systems ............................................................................................................... 22 4.1 Overview .............................................................................................................................................. 22 4.1.1 System start and end.......................................................................................................................... 22 4.2 Types of system .................................................................................................................................. 22 4.3 Design criteria ..................................................................................................................................... 22 4.4 Mains water supply systems and fittings ......................................................................................... 23 4.4.1 Location ............................................................................................................................................... 23 4.4.2 Materials .............................................................................................................................................. 23 4.4.3 Break tank and booster systems ...................................................................................................... 26 4.5 Cold water storage cisterns ............................................................................................................... 27 4.5.1 General ................................................................................................................................................. 27 4.5.2 Types of cisterns ................................................................................................................................ 27 4.5.3 Storage quantities, people and appliances ...................................................................................... 28 4.5.4 Storage location .................................................................................................................................. 28 4.5.5 Inter-connected cold water storage cisterns ................................................................................... 29 4.5.6 Legionnaires’ disease considerations.............................................................................................. 29 4.6 Cold water supply systems and fittings ........................................................................................... 29 4.6.1 Supplied from storage ........................................................................................................................ 29 4.6.2 Pumped systems ................................................................................................................................ 29 4.6.3 Noise considerations and airlocks ................................................................................................... 30 4.6.4 Materials .............................................................................................................................................. 31 4.6.5 Terminal fittings .................................................................................................................................. 34 4.6.6 Water conservation ............................................................................................................................. 39 4.6.7 Meters .................................................................................................................................................. 40 4.7 Reclaimed water systems .................................................................................................................. 43 4.7.1 Protection of potable water supply ................................................................................................... 43 4.7.2 Contamination of reclaimed water .................................................................................................... 44 4.7.3 Design considerations ....................................................................................................................... 45 4.7.4 Reclaimed water treatment ................................................................................................................ 45 4.7.5 Reclaimed water uses ........................................................................................................................ 46 4.8 Commissioning and handover .......................................................................................................... 46 4.9 Schedule of maintenance .................................................................................................................. 46

5 Hot water supply systems ................................................................................................................. 47 5.1 General ................................................................................................................................................. 47 5.2 Types of systems ................................................................................................................................ 47 5.2.1 Storage ................................................................................................................................................. 47 5.2.2 Vented .................................................................................................................................................. 47 5.2.3 Unvented .............................................................................................................................................. 47 5.3 Design criteria ..................................................................................................................................... 48 5.3.1 Secondary distribution systems ....................................................................................................... 48 5.3.2 System components ........................................................................................................................... 48 5.3.3 Open vent pipe .................................................................................................................................... 48 5.3.4 Circulating pump ................................................................................................................................ 49 5.3.5 Valves and taps ................................................................................................................................... 49

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5.3.6 Storage vessels ................................................................................................................................... 49 5.3.7 Electric immersion heaters for storage vessels .............................................................................. 50 5.3.8 Miscellaneous ...................................................................................................................................... 50 5.3.9 Supplementary water heating and independent summer water heating ...................................... 50 5.3.10 Storage quantities required ............................................................................................................... 50 5.3.11 Legionnaires disease considerations ............................................................................................... 51 5.3.12 Energy and system efficiency............................................................................................................ 51 5.3.13 Cold water supply ............................................................................................................................... 51 5.4 Types of hot water generators ........................................................................................................... 52 5.4.1 Instantaneous gas or electric ............................................................................................................ 52 5.4.2 Electric storage water heaters ........................................................................................................... 53 5.4.3 Direct and indirect systems ............................................................................................................... 53 5.5 Stratification and re-circulation of hot water ................................................................................... 55 5.6 Health and Safety Considerations ..................................................................................................... 56 5.6.1 Thermostatic/anti-scald devices ....................................................................................................... 56 5.6.2 Vented system: .................................................................................................................................... 56 5.6.3 Bursting and explosion ...................................................................................................................... 56 5.7 Commissioning and handover........................................................................................................... 57 5.7.1 Flushing ............................................................................................................................................... 57 5.7.2 Disinfection .......................................................................................................................................... 57 5.7.3 Testing .................................................................................................................................................. 57 5.8 Schedule of maintenance ................................................................................................................... 57 5.8.1 General ................................................................................................................................................. 58 5.8.2 Pipework .............................................................................................................................................. 58 5.8.3 Terminal fittings, valves and meters ................................................................................................. 58 5.8.4 Cisterns ................................................................................................................................................ 59 5.8.5 Access ducts ....................................................................................................................................... 59 5.8.6 Vessels under pressure ...................................................................................................................... 59 5.8.7 Disconnection of used pipework and fittings .................................................................................. 59

6 Above Ground Sanitation Systems ................................................................................................... 60 6.1 Types of systems ................................................................................................................................ 60 6.1.1 Primary ventilated stack system ....................................................................................................... 60 6.1.2 Single stack system variations .......................................................................................................... 60 6.2 Design criteria ..................................................................................................................................... 60 6.2.1 Pipework .............................................................................................................................................. 60 6.2.2 Branch connections ............................................................................................................................ 61 6.2.3 Termination .......................................................................................................................................... 61 6.2.4 Access .................................................................................................................................................. 61 6.2.5 Traps and trap seal protection........................................................................................................... 61 6.2.6 Air Admittance Valves ........................................................................................................................ 62 6.2.7 Materials ............................................................................................................................................... 62 6.2.8 Connection to under ground systems .............................................................................................. 62 6.3 Rainwater ............................................................................................................................................. 62 6.3.1 Sizing .................................................................................................................................................... 62 6.3.2 Fixing .................................................................................................................................................... 63 6.4 Sanitary accommodation & apartments ........................................................................................... 63 6.4.1 Ventilation ............................................................................................................................................ 63 6.5 Commissioning and handover........................................................................................................... 63 6.6 Maintenance......................................................................................................................................... 63 6.6.1 Blockages ............................................................................................................................................ 63 6.6.2 Regular Maintenance .......................................................................................................................... 64

7 Space Heating Systems - System Design ........................................................................................ 67 7.1 Overview .............................................................................................................................................. 67 7.2 Objective .............................................................................................................................................. 67 7.3 Boiler Efficiency .................................................................................................................................. 67 7.4 HARP .................................................................................................................................................... 68 7.5 Central heating design ....................................................................................................................... 68 7.6 Fabric Heat loss .................................................................................................................................. 69

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7.7 Ventilation Rate ................................................................................................................................... 69 7.8 Thermal comfort .................................................................................................................................. 70 7.8.1 Building exposure ............................................................................................................................... 70 7.9 Design Temperatures ......................................................................................................................... 71 7.9.1 External design temperatures ........................................................................................................... 71 7.9.2 Internal design temperatures and ventilation rates ........................................................................ 71 7.9.3 Calculating heat loss from a room .................................................................................................... 72 7.10 Requirements for ventilation ............................................................................................................. 75 7.10.1 Ventilation Heat loss........................................................................................................................... 77 7.10.2 Ventilation rates .................................................................................................................................. 77 7.10.3 Mechanical extraction ventilation ..................................................................................................... 77

8 System Selection ................................................................................................................................ 79 8.1 Fuel selection and type ...................................................................................................................... 79 8.2 Renewable Energy systems: ............................................................................................................. 79 8.2.1 Solar Thermal systems: ..................................................................................................................... 79 8.2.2 Biomass heating systems: ................................................................................................................ 80 8.2.3 Heatpump thermal systems ............................................................................................................... 83 8.3 Domestic Heating Oil Storage Tanks ................................................................................................ 84 8.3.1 Introduction ......................................................................................................................................... 84 8.3.2 Installation ........................................................................................................................................... 84 8.3.3 Oil Supply ............................................................................................................................................ 85 8.3.4 Secondary containment ..................................................................................................................... 85 8.4 Oil-fired hot water and space heating systems ............................................................................... 93 8.4.1 General ................................................................................................................................................. 93 8.4.2 Oil boiler location. ............................................................................................................................... 93 8.5 Oil fired wet heating system .............................................................................................................. 94 8.5.1 Service and maintenance ................................................................................................................... 95 8.5.2 Range cooker boilers ......................................................................................................................... 95 8.6 Room heaters (stoves) ....................................................................................................................... 97 8.7 Liquefied petroleum gas (LPG) ......................................................................................................... 97 8.8 Condensing Boilers ............................................................................................................................ 98 8.8.1 Design Considerations ....................................................................................................................... 98

9 Central Heating Distribution System ................................................................................................ 99 9.1 Pipework .............................................................................................................................................. 99 9.1.1 Pipework general ................................................................................................................................ 99 9.1.2 Jointing & bending ............................................................................................................................. 99 9.1.3 Pipework support & expansion ......................................................................................................... 99 9.1.4 Pipework protection ........................................................................................................................... 99 9.2 Pipe sizing ......................................................................................................................................... 100 9.3 Pipework insulation and frost protection ....................................................................................... 100 9.3.1 Insulation general ............................................................................................................................. 100 9.3.2 Insulation of heating circuit pipework ............................................................................................ 100 9.3.3 Boiler frost protection ...................................................................................................................... 101 9.4 Circulators ......................................................................................................................................... 101 9.4.1 Pumps General .................................................................................................................................. 101 9.4.2 Duty and operation ........................................................................................................................... 101 9.4.3 Electrical connection ........................................................................................................................ 101 9.4.4 HARP rating ....................................................................................................................................... 101 9.5 Open vented feed and expansion systems .................................................................................... 101 9.5.1 Open vented systems General ........................................................................................................ 101 9.5.2 Feed and Expansion Cisterns ......................................................................................................... 102 9.5.3 Cold mains water supply ................................................................................................................. 102 9.5.4 Overflow pipes .................................................................................................................................. 102 9.5.5 Cold feed make-up ............................................................................................................................ 102 9.5.6 Open vent pipe .................................................................................................................................. 103 9.6 Sealed feed and expansion systems (pressurised) ...................................................................... 103 9.6.1 Sealed systems general ................................................................................................................... 103 9.6.2 Expansion vessels ............................................................................................................................ 103

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9.6.3 Connection of expansion vessel ..................................................................................................... 104 9.6.4 Filling of sealed systems .................................................................................................................. 104

10 System control .................................................................................................................................. 105 10.1 System controls ................................................................................................................................ 105 10.2 Space heating and hot water supply system controls - compliance with building

regulations. ........................................................................................................................................ 105 10.3 By-pass arrangements ..................................................................................................................... 108

11 Interlinking ......................................................................................................................................... 110 11.1 Heat dissipation on a traditional solid fuel system ....................................................................... 110 11.2 Interlinking of solid fuel fired and oil or gas or renewable—fired heat generators rationale .. 110 11.2.1 System requirements ........................................................................................................................ 110 11.2.2 Gravity circulation ............................................................................................................................. 111 11.3 Types of link-up ................................................................................................................................. 111 11.3.1 Direct link-up - solid fuel with gas/oil) ............................................................................................ 111 11.3.2 Indirect link-up - solid fuel with gas/oil ........................................................................................... 112 11.3.3 Completely linked systems - solid fuel with gas/oil ...................................................................... 113 11.3.4 Neutralising systems - solid fuel with gas/oil - Renewables with gas/oil/electric ...................... 115 11.3.5 Electronically controlled link–up - solid fuel with gas/oil ............................................................. 117 11.3.6 Thermal store or accumulator system ............................................................................................ 118

12 Commissioning, Handover and Maintenance ................................................................................ 120 12.1 General ............................................................................................................................................... 120 12.2 System cleaning and power flushing .............................................................................................. 120 12.2.1 General ............................................................................................................................................... 120 12.2.2 Magnetic cleansing ........................................................................................................................... 120 12.2.3 Power flushing combined with a portable magnetic filter ............................................................ 121 12.2.4 Magnetic filtration ............................................................................................................................. 121 12.3 Commissioning ................................................................................................................................. 121 12.4 Filling all system types contain water as the transfer medium .................................................... 122 12.5 System filling ..................................................................................................................................... 122 12.5.1 Open systems .................................................................................................................................... 122 12.5.2 Sealed systems ................................................................................................................................. 122 12.5.3 Auto Fill Systems .............................................................................................................................. 122 12.5.4 Boiler firing ........................................................................................................................................ 123 12.5.5 Manuals and documentation ............................................................................................................ 123

13 Abbreviations .................................................................................................................................... 124

Annex A (informative) Fluid categories and examples ............................................................................... 125

Annex B (informative) Electrical considerations ......................................................................................... 127

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Foreword

The aim of this Code of Practice is to promote higher standards of quality in the design, installation, maintenance and commissioning of domestic plumbing and heating systems.

This Code of Practice has been prepared with the assistance of the National Standards Authority of Ireland Building Services Committee, representation on which includes the following;

The recommendations given in this Code of Practice have been drawn up to encourage uniformity of application.

Refer to the National Rules for Electrical Installations (ET 101), published by The Electro-Technical Council of Ireland for wiring requirements.

There are a number of Annexes to this Standard. These Annexes are referred to as either Normative or Informative Annexes. Normative Annexes are mandatory for compliance with this Standard whereas Informative Annexes are for information only.

Compliance with an Irish Standards Recommendation does not in itself confer immunity form legal obligations.

Introduction

The document has been prepared by members of the NSAI's Building Services Consultative Committee Chaired by John Smartt, D.I.T. This committee has two Working Groups, WG 1 Plumbing, Chaired by John Kealy, Plumber on Duty and WG 2 Heating, Chaired by Joe Durkan, SEAI. The bulk of the text was drafted by John Kealy, Plumber on Duty, Joe Durkan, SEAI, Damien Keenan, Institute of Technology Blanchardstown (ITB), Jerry Bradley, ITB, Michael Gleeson, D.I.T. and Sean Armstrong, DOEHLG.

Members of the committee will be published in the final document.

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1 Scope

This document specifies the requirements for the design, installation, commissioning & maintenance of plumbing and heating systems for domestic buildings. The document takes full account of all relevant European standards in this area and the Building Regulations Technical Guidance Documents.

2 Normative references

The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

• C H Systems • Fuels • Heat Emitters • Pipe Work • Sanitary • Water Supply

Standards

I.S. 161:1975, Copper direct cylinders for domestic purposes

I.S. 265: 2000 (all parts), Installation of gas service pipes

I.S. 813:2002, Domestic gas installations

I.S. EN ISO 10077-1:2006 Thermal performance of windows, doors and shutters - Calculation of thermal transmittance - Part 1: General

I.S. EN ISO 10077-2:2003, Thermal performance of windows, doors and shutters - Calculation of thermal transmittance - Part 2: Numerical method for frames

I.S. EN ISO 10211:2006, Thermal bridges in building construction - Heat flows and surface temperatures – detailed calculations

I.S. EN 12056-3, Gravity drainage systems inside buildings - Part 3: Roof drainage, layout and calculation

I.S. EN 12056-5, Gravity drainage systems inside buildings - Part 5: Installation and testing, instructions for operation, maintenance and use

I.S. EN 1264-1:1998, Floor heating – systems and components — Part 1: definitions and symbols

I.S. EN 1264-2:2008, Floor heating – systems and components — Part 2: determination of the thermal output

I.S. EN 1264-3:1998, Floor heating – systems and components — Part 3: dimensioning

I.S. EN 1264-4:2001, Floor heating – systems and components — Part 4: installation

I.S. EN 12828:2003, Heating systems in buildings – design for water-based heating systems

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I.S. EN 12831:2003, Heating Systems in Buildings – method for calculation of the design heat load

I.S. EN 12897:2006, Water supply - Specification for indirectly heated unvented (closed) storage water heaters

I.S. EN ISO 13789:2007, Thermal performance of buildings - Transmission heat loss coefficient - Calculation method

I.S. EN 14336:2004, Heating systems in buildings – installation and commissioning of water based heating systems

I.S. EN 14337:2006, Heating systems in buildings – design and installation of direct electrical room heating systems

I.S. EN 15034:2008, Heating Boilers – Condensing heating boilers for fuel oil

I.S. EN 15270:2007, Pellet Burners for small heating boilers – definitions, requirements, testing, marking

I.S. EN 15316-1:2007, Heating systems in buildings - method for calculation of system energy requirements and system efficiencies — Part 1: General

I.S. EN 15316-2-1, Heating systems in buildings - method for calculation of system energy requirements and system efficiencies — Part 2-1: Space heating emission systems

I.S. EN 15316-2-3, Heating systems in buildings - method for calculation of system energy requirements and system efficiencies — Part 2-3: Space heating distribution systems

I.S. EN 15377-1:2007, Heating systems in buildings – Design of embedded water based surface heating and cooling systems — Part 1: Determination of the design heating and cooling capacity

I.S. EN 15377-2:2007, Heating systems in buildings – Design of embedded water based surface heating and cooling systems — Part 2: Design, dimensioning and installation

I.S. EN 15377-3:2008, Heating systems in buildings – Design of embedded water based surface heating and cooling systems — Part 3: Optimizing for use of renewable energy sources

I.S. EN 15450:2007, Heating systems in buildings – Design of heat pump heating systems

I.S. EN 60335-2-21:2003, Household and similar electrical appliances – Safety — Part 2-21: particular requirements for storage water heaters

I.S. EN 60730-2-2:2006, Automatic electrical controls for household and similar use — Part 2-2: particular requirements for thermal motor protectors

I.S. EN 1717:2000, Protection against pollution of potable water in water installations and general requirements of devices to prevent pollution by backflow

I.S. EN ISO 6946:2007, Building components and building elements - Thermal resistance and thermal transmittance - Calculation method

I.S. EN 806-1, Specifications for installations inside buildings conveying water for human consumption - Part 1: General

I.S. EN 806-2:2005, Specification for installations inside buildings conveying water for human consumption - Part 2: Design

I.S. EN 806-3, Specifications for installations inside buildings conveying water for human consumption - Part 3: Pipe sizing - Simplified method

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BS 2869: 2006

BS 3198 Specification for copper hot water storage combination units for domestic purposes

BS 5440-1:2008, Flueing and ventilation for gas appliances of rated input not exceeding 70 kW net (1st, 2nd & 3rd family gases) — Part 1: Specification for installation of gas appliances to chimneys and for maintenance of chimneys

BS 6700

BS 7593:2006 CODE OF PRACTICE FOR TREATMENT OF WATER IN DOMESTIC HOT WATER CENTRAL HEATING SYSTEMS

BS 7671

BS EN 673 Glass in building - Determination of thermal transmittance (U-value) - Calculation method

BS 1566:2002 Part 1 Copper cylinders for domestic purposes - PART 1: Open vented copper cylinders - Requirements and test methods

BS 1566:1984 Part 2 Copper indirect cylinders for domestic purposes - Specification for single feed indirect cylinders

BS 8233, Sound Insulation and Noise Reduction for Buildings Code of Practice

BS 8303-1:1994, Installation of domestic heating and cooking appliances burning sold mineral fuels – specification for the design of the installations

I.S. EN ISO 13370 Thermal performance of buildings - Heat transfer via the ground - Calculation methods

Legislation

Technical Guidance Document H, Dept. of Environment

Technical Guidance Document G, Dept. of Environment

WRAS Information and Guidance Note on Reclaimed Water Systems, No. 9-02-04, August 1999, Issue 1

Plumbing for Level 2 Technical Certificate and NVQ, 2nd Edition, Steve Muscroft, Newnes 2005

Building Regulations 1997-2009, (Technical Guidance Documents)

Building Regulations 2008 TGD L Section 2.2 Building Services

EU Drinking Water Regulations

SI 556 of 2009, Building Regulations (Part F Amendment) Regulations 2009

SI No 581 of 2002 The Building Regulations (Amendment) (No 2) Regulations 2002

SI No 872 of 2005 European Communities (Energy Performance of Buildings) Regulations 2005

Heating and Domestic Hot Water Systems for Dwellings- Achieving Compliance with Part L 2008

I.S. 3216 Part 1 Code of Practice for Bulk Storage Tanks (including amendments).

Codes of Practice

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National Guidelines for the Control of Legionellosis in Ireland, 2009, Health Protection Surveillance Centre, ISBN 978-0-9551236-4-1

I.S. 3213: 1987 Code of Practice for the storage of LPG cylinders and cartridges

BRE BR 443 Conventions for U-value calculations

BRE IP 5/98 Metal cladding: Assessing thermal performance

BRE IP 1/06 Assessing the effects of thermal bridging at junctions and around openings

BRE IP 10/02 Metal cladding: Assessing the thermal performance of built-up systems which use ‘Z’ spacers

CWCT Standard for specifying and assessing for heat transfer (the U-value)

CWCT Guide to good practice for assessing heat transfer and condensation risk for a curtain wall

CWCT Guide to good practice for assessing glazing frame U-values

GGF 2.2 Window and door system U-values: Provision of certified data

CAB Guide for assessment of the thermal performance of aluminum curtain wall framing

CAB A guide for assessment of the thermal performance of aluminum windows

Heating and Domestic Hot Water Systems for dwellings – Achieving compliance with Part L 2008, Dept. of Environment and Local Government

Plumbing engineering services design guide, The Institute of Plumbing, 2002

WRAS

OFTEC Technical Book 3

3 Terms and definitions

For the purposes of this document, the following terms and definitions apply / the terms and definitions given in … and the following apply.

3 Port valve allows hot water to flow in one of two possible directions. In the case of a radiator hot water can either enter the radiator or bypass the radiator depending on the position of the valve

anti-cycling control delays boiler firing to reduce cycling frequency

automatic bypass valve ensures a minimum flow through the boiler

backflow means flow upstream that is in a direction contrary to the intended normal direction of flow, within or from a water fitting

bayonet connector two-part valve used with an appliance flexible connection. The plug is attached to the inlet end of the flexible connection and the socket is attached to the installation pipe. The socket includes a valve that opens as the

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plug is inserted and closes as it is removed. During insertion, the plug is rotated and locked in position by spring action

boiler anti-cycling device device to introduce a time delay between boiler firing. Any energy saving is due to a reduction in performance of the heating system. The device does not provide boiler interlock.

boiler auto ignition electrically controlled device to ignite the boiler at the start of each firing, avoiding use of permanent pilot flame.

boiler energy manager intended to improve boiler control using a selection of features

EXAMPLES weather compensation, load compensation, optimum start control, night setback, frost protection, anti-cycling control and hotwater over-ride

boiler heating services direct surfaces of the boiler receive heat directly from the heat source

boiler heating services indirect surfaces of the boiler receive heat indirectly from the fire, usually through internal flue ways

boiler Interlock wiring arrangement and physical arrangement of pipes and fittings, that prevents the boiler from firing when there is no demand for heat

boiler modulator (air temperature) device or feature within a device to vary the fuel burning rate of a boiler according to measured room temperature. The boiler under control must have modulating capability and a suitable interface for connection

boiler modulator (water temperature) device or feature within a device to vary the fuel burning rate of a boiler according to measured water temperature. It is often fitted within a boiler casing. The boiler under control must have a modulating capability

boiler rated output the power of the boiler rated in kilowatts/hour (kW/h)

boiler thermostat thermostat within the boiler casing to limit the temperature of water passing through the boiler by switching of the boiler. The target temperature may either be fixed or set by the user

calorifier vessel in which water is heated by means of an internal heat exchanger

cistern fixed container for holding water at atmospheric pressure

class A water class A is potable water and as such its handling and treatment shall conform to the relevant standards and the EU Drinking Water Regulations. As a result, the systems should be designed and constructed appropriately. To conform to class water must meet the relevant standards as laid down by the relevant local water authority

class B water regulations governing class B water quality vary and depend on its intended purpose. Water quality parameters should be specified in advance and regular measurements taken

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closed type or sealed heating installation installation which does not have any open connection with the atmosphere but which incorporates a sealed expansion vessel

cold feed pipe pipe connecting the cistern to the hot water system

combined boiler and storage vessel boiler unit on which is superimposed a storage vessel

combined feed and expansion cistern cistern for supplying cold water to a hot water system without a separate expansion cistern

condensing appliance appliance designed to utilise a proportion of the latent heat of condensation of the water vapour in the combustion products

contamination includes any reduction in chemical or biological quality of water due to a change in temperature or the introduction of polluting substances

competent person person having the ability, appropriate training, knowledge and experience to carry out work being undertaken in a safe and proper manner

cylinder thermostat sensing device to measure the temperature of the hot water cylinder and switch on and off the water heating. A single target temperature may be set by the user.

dead leg single pipe for drawing off hot water from a calorifier, cylinder or tank

delayed start reduces energy use by delaying the boiler start-up when the weather is mild

DN alphanumeric designation of size for components of a pipework system which is used for reference purposes. It comprises the letters DN followed by dimensionless whole number, which is indirectly related to the physical size in millimetres of the bore or outside diameter of the end connections

NOTE 1 the number following the letters DN does not represent a measurable value and should not be used for calculation purposes where specified

NOTE 2 where DN designation is used, any relationship between DN and component dimensions are given, e.g. DN/OD or DN/ID

domestic hot water cylinder thermostat measures the temperature of the water in the cylinder and switches the water heating system on and off accordingly. It also prevents unnecessary heating of the hot water

equipotential bonding means to ensure that metallic gas pipework and other metallic parts of structures are at the same electrical potential

expansion valve means a pressure-activated valve designed to release expansion water from an unvented water heating system

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feed and expansion cistern an open-top vessel for maintaining the water level in the system and for accommodating increases in the volume of water due to expansion

flexible connector device for connecting two rigid pipes or pipe fittings, designed to accommodate a limited movement between them in more than one plane

flow switch detects when there is no flow through the system:

EXAMPLE when the TRV’s on all radiators are closed

frost thermostat, low-limit thermostat override device that detects low air temperature, switching on the heating system to prevent frost damage

flue passage for conveying the products of combustion from the outlet of the appliance to the outside atmosphere

flueless appliance designed for use without connection to a flue system, the products of combustion being allowed to mix with the air in a room or space in which the appliance is situated

gas gaseous fuel which is in gaseous state at a temperature of 15°C under atmospheric pressure (1,01325 bar absolute)

gas distribution activity of supplying gas through pipelines upstream of the point of delivery

gas supplier private or public organisation authorised to supply or distribute gas to consumers

gas supply system pipeline systems including pipework and their associated stations or plants for the transmission and distribution of gas

grey water water originally from the mains supply that has been used for processes such as washing, bathing or laundering clothes

hazard source or situation with a potential for harm in terms of human injury or ill health, damage to property, damage to the environment or a combination of these

heat generator/source appliance commonly termed as 'boiler' designed to heat water as the heat transfer medium for circulation to points of usage (heat emitters)

hot water cylinder closed cylindrical vessel in which hot water is stored

hot water tank closed rectangular vessel in which hot water is stored

indirect cylinder small domestic storage calorifier

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isolating valve valve used to isolate a circuit

installation pipework (LPG) all components forming the route by which gas passes from the container outlet valve to points at which appliances are to be connected

installation pipework (natural gas) all components forming the route by which gas passes from the meter outlet or point of delivery to points at which appliances are to be connected

instantaneous water heater appliance in which water is heated only as it flows to the point of delivery

interlinked heating installation system based around the concept of linking up two or more heat producing appliances so that either one or both can be used as the heat source.

interlock safety system which, when activated shuts off a burner or burner control equipment and prevents re-ignition until normal operating conditions are achieved

irrigation water water used for the purpose of irrigating plants and gardens.

isolation valve valve system which permits isolation of a part of, or the complete installation

liquefied Petroleum Gas (LPG) generic term used to describe gases having the characteristic of being easily liquefied by the application of pressure. It is provided as commercial butane and commercial propane or mixtures thereof

load Compensator A load compensator is a device or a feature within a device that adjusts the temperature of the water circulating through the heating system according to the inside temperature measurement. This will increase the efficiency of condensing boilers.

lock-out safety shut-down condition of a control system such that re-start cannot be accomplished without manual operation

maintenance combination of all technical and associated administrative actions intended to keep an item in, or restore it to, a state in which it can perform its required function safely

modern (To be defined) solid fuel boiler (biomass) a boiler that is fired on refined wood fuels where the fuel feeding, ignition and ash removal are fully automated. This type of boiler therefore may be described as one that has the same thermostatic control as that of oil or gas boiler, which can effectively be switched off instantaneously.

motorised valve A 2-port or 3-port valve used in conjunction with room and DHW thermostats to control water flow from the boiler to the heating and hot water circuits. Motorised valves can be used to provide zone control e.g. separate time and temperature control.

multi-occupancy dwelling building containing two or more dwelling units. This includes the following:

a purpose built apartment building accommodating two or more separate dwellings,

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an existing single dwelling modified to accommodate two or more separate dwellings,

dwelling units contained in a mixed use building, e.g. shops/offices downstairs and more than one dwelling unit above

NOTE A building may be an individual terraced house or "town-house"

narrow temperature differential Reduces the temperature difference that triggers the boiler to switch on. This increases comfort levels and allows a lower set temperature which can reduce overall energy consumption.

natural gas gas largely consisting of methane, distributed through a network of pipes

night setback a feature of a room thermostat that allows a lower temperature to be maintained outside the period during which the normal room temperature is required

nominal capacity the total volume of a cistern, tank or cylinder calculated from the external dimensions of these vessels.

occupier owner or other person who has charge of the gas installation for a building

open-flued appliance appliance designed to be connected to an open-flue system, its combustion air being drawn from the room or space in which it is installed

open-flued fan assisted appliance appliance incorporating a fan upstream or downstream of the burner taking combustion air from a room

open-flue system flue system that is open to a room or internal space at each appliance position

open type heating installation an installation which has an open connection to atmosphere via a safety vent pipe and a high level expansion/feed vessel. Feed and expansion tanks and float operated valves shall be of material suitable for 120°C water temperature and comply with relevant Irish Standards / British Standards and local authority bye—law requirements. (interim definition – to be defined)

open vent an open pipe from any high point in a hot-water system or from any closed vessel containing hot water.

operating pressure pressure which occurs within a system under normal operating conditions

operating temperature temperature which occurs within a system under normal operating conditions

optimum Start An optimum start adjusts the start time of the boiler to give the required dwelling comfort temperature at a chosen time.

optimum Stop A device, or feature within a device, to adjust the stop time for space heating according to the temperature measured inside (and possibly outside) the building, aiming to prevent the required temperature of the building being maintained beyond a chosen time

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overflow pipe means a pipe from a cistern in which water flows only when the water level in the cistern exceeds a predetermined level.

oxygen depletion sensor device designed to shut off the main gas supply when the oxygen content of the surrounding atmosphere is reduced to a given level

pigtail (LPG) flexible connector (usually hose but may be metallic) which is relatively short (typically less than 1 metre) for connecting the service valve of an LPG cylinder or tank to the installation

piping/pipework assembly of pipes and fittings

point of delivery point immediately downstream of the control device fitted to terminate the service pipe

NOTE 1 Natural gas service pipes terminate in a combination of a regulator and isolation valve.

NOTE 2 Distributed LPG service pipes terminate in an isolation valve.

NOTE 3 For LPG, other than LPG distribution systems, the point of delivery is at the outlet of the storage vessel isolation valve.

NOTE 4 This definition indicates the point at which the gas installation to a building commences but does not necessarily indicate the point at which ownership of the gas supplied to the building is transferred.

pipe thermostat The pipe thermostat is used in conjunction with the frost thermostat to prevent unnecessary operation of the boiler in cold weather, thereby reducing running costs.

pressure gauge pressure of the fluid inside the system, measured in static conditions

pressure relief valve means a pressure-activated valve which opens automatically at a specified pressure to discharge fluid.

primary circuit means an assembly of water fittings in which water circulates, between a boiler or other source of heat and a primary heat exchange inside a hot water storage vessel, and includes any space heating system.

programmable cylinder thermostat a combined time switch and cylinder thermostat which allows the user to set different periods with different target temperature for stored hot water, usually in a daily or weekly cycle.

programmer / Programmable control Responds to internal and external temperature and adjust the space heating and hot water on / off times to optimise energy use. There are a range of models available with varying levels of complexity depending on the application.

programmable room thermostat A programmable room thermostat allows the temperature in the room to be set for different periods in the day or week. This allows the system to be tailored for varying occupancy.

propane hydrocarbon mixture, as commercially supplied, consisting predominately of propane, propylene or any mixture thereof

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pump over-run a timing device to run the heating system pump for a short period after the bolier stops firing to discharge very hot water from the boiler heat exchanger

pump modulator a device to reduce pump power when not needed, determined by hydraulic or temperature conditions or firing status of the boiler

purge/purging procedure for safely removing air or inert gas from pipework and replacing it with combustible gas, or the reverse procedure

rainwater Water that has been collected from roofs and other hard standing areas.

reclaimed Water Water, other than the mains water supply, that has been suitably collected and treated for a specific use e.g. WC flushing, irrigation.

reclaimed Water System An installation for the collection, storage, treatment and distribution of reclaimed water

re-commissioning activities required to put decommissioned pipework and associated equipment into service again

regulator (governor) device for automatic control of pressure or of volume flow at a selected point in a gas stream

room-sealed appliance (fan assisted) room-sealed appliance incorporating a fan upstream or downstream of the burner

room-sealed flue system flue or duct system that is not open to any room or internal space

room thermostat A room thermostat measures the air temperature in the room allowing heat to be supplied to the room when required (either via a motorised valve, pump or by controlling the boiler directly). The thermostat can also operate by turning off the heating system when a set temperature is reached.

safety device equipment designed to automatically shut off the fuel supply or to limit it, in the event of the actual condition exceeding a pre-set limit

secondary circuit means an assembly of water fittings in which water circulates in supply pipes or distributing pipes of a hot water storage system.

secondary system means an assembly of water fittings comprising the cold feed pipe, any hot water storage vessel, water heater and pipework from which hot water is conveyed to all points of draw-off.

self-adaptive (or self-learning) control a characteristic of a device which learns from experience by monitoring, and modifies its subsequent behaviour accordingly

self-learning Reduces appliance on time by taking account of previous characteristics.

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service pipe (service line) pipe from the gas distribution main to the point of delivery of the gas

service shaft space specifically designed and constructed for the passage of building services

servicing valve means a valve for shutting off for the purpose of maintenance or service the flow of water in a pipe connected to a water fitting.

sleeve length of protective pipe through which a gas pipe passes

soundness test (tightness test) specific procedure to verify that the pipework and/or station meets the requirements for leak tightness

stop valve device used to stop or regulate the flow of fluid by the closure or partial closure of an orifice

storage water heater appliance in which a volume of water is heated under thermostatic control and stored for use when required

storey any of the parts into which a building is divided horizontally above or below ground level, excluding any structure situated above the level of the roof or below the level of the lowest floor, which is intended for the protection of a water tank or lift motor or similar use and is not intended for or adapted to be used for habitable purposes or as a workroom or as a store room

temperature and time zone control(or full zone control) a control scheme in which it is possible to select different temperatures at different times in two or more different zones

temperature relief valve means a valve which opens automatically at a specified temperature to discharge fluid.

temperature setback, night setback Setback allows a reduced temperature to be maintained at certain times, for example at night. This reduces the risk of condensation and improves comfort by reducing dwelling warm up times.

terminal fitting means a water outlet device.

test pressure pressure to which the pipe distribution system is subjected to ensure that it can operate safely without leaks

thermostatic radiator valve (TRV) Controls flow of hot water to radiator based on room temperature. The TRV has a number of settings based on the temperature required. Bedrooms normally set lower than living areas. TRV’s reduce energy consumption where there are incidental gains and solar gain.

threaded joint joint in which gas tightness is achieved by metal to metal contact within threads with the assistance of a sealant

time switch / time clock A time switch provides for simple time control of a system or part of a system

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traditional (To be defined) solid fuel boiler (multi-fuel boiler) a boiler that can be fired on a number of solid fuels and for the purposes of this definition – one that is manually fed. This type of boiler may have a partial means of control – thermostatically controlled air damper and/or thermostatically controlled circulating pump. Therefore the output to the heating circuits from a solid fuel fired heat generator can only be reduced gradually.

vent pipe means a pipe open to the atmosphere which exposes the system to atmospheric pressure at its boundary.

weather compensator a weather compensator is a device that adjusts the temperature of the water circulating through the heating system according to the outside temperature measurement. This will increase the efficiency of condensing boilers while at the same time performing the same function as a frost thermostat.

Pumping definitions capacity The flow rate discharged by a pump, usually expressed in m3 /h or L/s

static delivery head The vertical distance between the centre-line of the pump and the free surface of the discharged liquid.

negative suction lift This exists when the pump is above the liquid to be pumped and is the vertical distance from the centre line of the pump down to the free surface of the liquid.

total suction lift The distance from the centre line of the pump to the bottom of the suction pipe.

friction head The head necessary to overcome resistance to flow of the liquid.

total delivery head The friction head plus the static delivery head plus the total suction lift in the delivery pipe system.

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Figure 1 — Pumping Definitions

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4 Cold water supply systems

4.1 Overview

Cold water services shall be designed to provide cold water at the point of use and in quantities required by the user or specified by manufacturers of equipment and terminal fittings.

4.1.1 System start and end

The system shall be deemed to start at the point where the service pipe or incoming water supply main crosses the boundary of a dwelling and enters private lands or curtilages of buildings.

The cold water supply system shall be deemed to end when discharge commences to the waste or drainage system which is covered in clause 6.

4.2 Types of system

For most single occupancy dwellings up to three stories high where the incoming mains pressure is sufficient to cater for demand there are two types of cold water supply systems;

direct cold water systems whereby the cold water supply to all appliances is taken directly from the incoming supply main; and

indirect cold water supply systems whereby the cold water supply to all appliances is taken from a storage cistern with the exception of the kitchen sink which is supplied from the incoming supply main. Refer to TGD Part G.

Before deciding on whichever of the above systems, it shall be necessary to seek approval and guidance from Local Authorities when connecting to a municipal water supply source.

In the case of high level single occupancy dwellings above three stories it may be necessary to boost the incoming supply. This can be achieved in two ways:

By direct boosting where a pump is connected to the incoming supply;

By indirect boosting where a break cistern is fitted before connecting a booster pump

4.3 Design criteria

Consideration shall be given to keeping noise, which may be generated within the cold water supply system, to a minimum. This may include types of bracketing to be used, location of storage cisterns and types of terminal fittings.

Where terminal fittings include the installation of both hot and cold water supplies, the cold water tap shall be fitted on the right.

In the case of boosted supplies or where the water pressure is very high (in excess of 3 bar) consideration shall be given to the use of high pressure terminal fittings. In the case of WC flushing cisterns the correct size orifice shall be installed to minimise water hammer and noise within systems.

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4.4 Mains water supply systems and fittings

4.4.1 Location

Water-main layout should be designed in consultation with the responsible County Council in accordance with their general guidelines. The following are generally to be complied with when designing the water-main layouts:

All pipes shall have a minimum depth of cover of 750mm and maximum depth of 900mm measured from the top of the pipe to the finished ground surface;

House connections are not to be taken across roads except when approved by the County Council;

Water-mains should be laid to provide the optimum circulation in the local water network, i.e. dead ends should be avoided. If it is impossible to prevent a dead end, a duck-foot hydrant will be required at this point;

The location of Body Valves should be in arranged in such a manner as to ensure that no more than 40 properties (or 15 commercial units) lose water from a burst in the system;

All developments with more than 40 properties (or 15 commercial units) shall have a second branch supply to provide resilience to the local network;

No other service is to be located above or within 500mm of any water-mains, unless it is crossing over the water-main at right angles, where there must be a minimum of 250mm vertical clearance;

Water-mains shall not be laid under walls or areas designated for trees/shrubs/flowers;

The water-main shall be located a minimum of 1m from the boundary of private property or 5m clearance from a house or other structure, except when approved by the County Council;

Trunk water-mains of up to and including 300mm diameter must have a 5m sterilised area on each side of the water-main, whereas water-mains of greater than 300mm must have an 8m sterilised area on each side. Any deviations must be agreed with the County Council prior to commencement of works;

Only DI pipes are to be used where a water main crosses a public road, except where otherwise agreed;

All designs shall comply with the current Building Regulations, Water Byelaws, Water Services Act (2007) and County Council requirements;

Where a water-main is to be located in an area where 24 hour access is not available, that water-main shall be duplicated to maintain the water supply until access is available to carry out the repair. The second main shall be exactly the same as the first main in all regards (i.e. material, diameter and flow capacity etc.) For example where a water-main passes under a motorway, it shall be duplicated to allow the supply to be maintained and so that the main can be repaired at off-peak times. Sluice valves should be provided on both sides of the inaccessible area to allow the water supply to be redirected from the water main in use to the second main while the first main is being repaired; and

Where a water-main is to be located within a structure that water-main shall be duplicated and the mains shall be placed within sleeves to facilitate easy replacement of the pipe.

4.4.2 Materials

No materials, other than materials listed in this clause, shall be used without the prior approval of the County Council’s Water Services Department. It is the responsibility of the Contractor to ensure that all materials/fittings to be used on the site have been approved for use by the Water Services Department of the County Council in advance of work commencing.

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4.4.2.1 Water-main pipe material

The preferred water-main materials are indicated on the following table:

Size of Pipe (mm) Type Of Pipe

100 to 150 Mopvc, pvc-A, PE, DI

150 - 300 Mopvc, DI, PE

>300 DI

Table 1 — Water-mains pipe material

All plastic water pipes shall be blue in colour;

Pipes shall be constructed from materials on the UK DWI Material List which are suitable for drinking water;

UPVC pipes are no longer accepted;

MOPVC pipes shall conform to I.S. EN 12201, EN 13224 and in relation to polyethylene pipe welding to the UK Water Industry Specification No. 4-31–08 and manufacturers shall operate a quality system in compliance with I.S. EN ISO 9001;

Ductile iron pipes shall conform to Class K9 of EN 545. Ductile iron fittings shall be either Class K9 or K12. Ductile Iron pipes and fittings shall be lined with a material that is approved for contact with drinking water;

PVC alloy pressure pipe and all fittings shall conform to BS PAS 27; and

PE pipes shall conform to I.S. EN 12201-1, I.S. EN 12201-2, I.S. EN 12201-5 and water industries specification 4.32.03 to 4.32.05 (inclusive) and 4.32.13.

4.4.2.2 Service pipes & fittings

MDPE pipe and fittings should be of type PE-X-80 and have an SDR rating of 11. They shall conform to the UK Water Industry Specification No. 4-32-02 and/or I.S. EN 12201-1, I.S. EN 12201-2 and I.S. EN 12201-5 for pipe sizes up to 63mm OD and No. 4-32-04 for fusion joints and fittings.

Copper Alloy fittings shall be approved gunmetal and conform to I.S. EN 12163, I.S. EN 12164, I.S. EN 12165, I.S. EN 12167 and I.S. EN 12420. (Material CZ132 resistant to de-zincification)

The diameter of the service pipe shall be approved in advance by the Water Services Department of the County Council.

4.4.2.3 Service pipe supplies

The service pipe shall not contain any break or joint between the boundary box and the first cold water appliance/outlet connected to the mains supply except for the provision of a stop valve.

4.4.2.4 Boundary box

All service pipes shall include the installation of a boundary box with integral stopcock (note that the use of the traditional stopcock has been discontinued). The boundary box comprises of a concentric meter box compatible with the County Council meters with telescopic body and circular plastic lid complete with shut-off

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valve, non-return valve and push-fits outlets. The minimum depth from lid to meter base-plate is 250mm and the lid structure is to match its required loading.

The boundary box may not be practical in all situations; however as a rule the boundary box shall be located in non-trafficked areas and within 225mm of the property boundary.

Domestic units shall each have an individual valve controlled supply, including the facility to retrofit a water meter at a later stage.

NOTE All alternative systems must be approved by the County Council’s Water Services Department prior to construction. Only County Council personnel are authorised to install water-main tapings. All properties must have 24hour water storage.

4.4.2.5 Sluice valves

Unless specified or approved by the County Council, all valves on water mains are to be sluice valves. Sluice valves shall be double flanged, ductile iron resilient seal gate valves for water-main purposes and shall comply with the relevant requirements of I.S. EN 1074. The number of turns to open/close the valve shall be;

n=2N + 1 where N = the equivalent diameter in inches.

All flanges shall be drilled to P.N. 16. The spindle shall be fitted with a cast iron oval false cap complete with grub screw. Depth from ground level to the top of the valve spindle must not be greater than 600mm. The operating torque should not exceed the maximum allowed in I.S . EN 1074, with written test results required.

A bypass valve should be provided to valves on high pressure pipelines to prevent water hammer when the valve is shut closed.

Sluice Valves shall be coated with an electrostatic epoxy powder spray, or bitumen – trichloroethylene solution to an approved coating.

All sluice valves are to be operated from above ground with a valve key and shall be ANTI-CLOCKWISE CLOSING.

4.4.2.6 Butterfly valves

Butterfly valves are only necessary where there is not enough space to install a sluice valve or where the valve is to be used to modulate the flow of water.

Butterfly valves shall be double flanged and shall conform to I.S. EN 1074. Manually operated butterfly valves are to be operated from above ground with a County Council valve key and the operating torque should not exceed the maximum allowed in I.S. EN 1074. All flanges shall be drilled to P.N. 16.

Butterfly valves shall be installed with the shaft in the vertical direction to allow the gear box to be installed above ground if deemed necessary.

Where gearboxes or actuators are located below ground, they should be rated for full submergence under IP68 for 3 weeks.

Butterfly valves shall be coated with an electrostatic epoxy powder spray, or bitumen – trichloroethylene solution to an approved coating.

All butterfly valves operated by a valve key shall be ANTI-CLOCKWISE CLOSING.

Actuated butterfly valves will require a manual over-ride facility and the actuator shall be IP rated to suit its location.

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4.4.2.7 Hydrants

Hydrants shall be manufactured in accordance with BS 750, Type 2 and shall incorporate a screw-down valve, underground, “guide in head” type, with bayonet lug outlets and false spindle.

The hydrant valve shall be CLOCKWISE CLOSING i.e. the opposite of a sluice valve.

Hydrants shall be coated with an electrostatic epoxy powder spray, or bitumen – trichloroethylene solution to U.K. WRAC or an alternative County Council approved coating.

Hydrants which are provided for emergency supply may not be used for any other purpose without the written permission of the County Council.

4.4.2.8 Air valves

Air Valves must comply with the requirements of ISO 7121 and are to be located at summits of water-mains or beside trunk water-main body valves. The County Council requires that all air valves are double orifice type and include an isolator valve to allow ease of removal without draining the water-main. Any other type of air valve is subject to the approval of the County Council prior to construction.

4.4.2.9 Non-return valves

Non-return or check valves are to be used to prevent water from draining back into the public water main only if a dedicated fire main is provided. These valves shall conform to the requirements of I.S. EN 1074. For fire fighting purposes there shall be no physical restriction to the flow through the valve.

4.4.3 Break tank and booster systems

4.4.3.1 Requirements for installation of booster systems

Where it is necessary to use a ‘Break tank and booster system’ (e.g. usually buildings of 4 storeys or more), the following conditions shall be complied with:

full details of the system shall be submitted to the Water Services Department of the County Council (including plumbing layout, maintenance programme, pump and tank details);

the relevant standards and supplier's conditions shall be adhered to, particularly the following;

I.S. EN 1508:1999 Requirements for systems and components for the Storage of Water; and

The European Communities (Drinking Water) Regulations 2007

Only indirect pressure boosting shall be permitted.

Separate independent drinking water supply (1hour storage not exceeded) and 24hr storage supply is required (one break tank for drinking water and another break tank for 24hr storage).

4.4.3.2 System maintenance

The designer is to supply the owner of the building/management company full as constructed details of the system installed including the system layout, recommended maintenance schedule and details of the appropriate maintenance required to ensure that the water quality is not compromised.

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4.5 Cold water storage cisterns

4.5.1 General

A cold water storage cistern is a vessel designed to hold a quantity of water at atmospheric pressure. Storage is recommended where an interruption of supply cannot be guaranteed.

4.5.2 Types of cisterns

4.5.2.1 Materials

Cold water storage cisterns shall be manufactured from materials that will not contaminate any water contained within them and also be corrosion resistant. Cold water storage cisterns not used to store drinking water should be fitted with lids or covers that are close fitting but not airtight and will prevent the entry of light and contaminants. Lids and covers shall be manufactured from materials that will not contaminate any condensate that will form on their underside and also be corrosion resistant.

Cold water storage cisterns shall also:

Have an overflow pipe at least one size larger than the inlet supply and a minimum of 19mm internal diameter;

Be protected against the effects of heat;

Be protected against the effects of freezing; and

Be fitted on a firm level base or platform capable of supporting the weight of the cistern when filled to its nominal capacity or spill level. Where plastic cisterns are installed the support base shall project at least 150mm beyond the underside of the cistern.

4.5.2.2 Overflow and warning pipes

Cisterns up to and including 1000 litres nominal capacity shall be fitted with at least one overflow pipe as described above.

Cisterns with a nominal capacity greater than 1000 litres shall be fitted with an overflow pipe and also with a warning pipe or similar device to indicate that the inlet control device is defective. Warning pipes shall be fitted 50mm below overflow pipe connections.

Overflow and warning pipes shall be manufactured from rigid materials that will not corrode and all joints should be non-flexible. They should be installed to ensure that they have a continuous fall to their point of discharge. Overflow and warning pipes shall discharge in a conspicuous location in order that the discharge can be readily noticed and rectified. The discharge from overflow and warning pipes should ideally cause a nuisance but not constitute a danger to people.

4.5.2.3 Inlet control devices

All cold water storage cisterns shall be fitted with an inlet control device similar to BS 1212 or equivalent. These devices shall be fitted as high as practical in the cistern and shall not cause any deformation. Where deformation is likely to occur (as in the case of some plastic cisterns) the inlet control device shall be braced.

4.5.2.4 Distribution pipes from storage cisterns

Where possible all distribution pipes from cold water storage cisterns should be taken from the opposite end from that of the inlet supply. Where this is not possible at least one such supply connection shall be taken from this opposite end.

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Connections from cold water storage cisterns shall be made as low as possible to prevent stagnation of water within cisterns and promote a good turnover of water.

In indirect cold water systems the cold water supply to the hot water storage calorifier or cylinder shall be at least 19mm in diameter for single occupancy dwellings and shall not supply cold water to any other appliance or installation.

The cold water supply to any hot water storage calorifier or cylinder shall be at least 25mm above any cold water connection to prevent scalding in the event of a reduction in supply.

4.5.2.5 Large cisterns

Where cold water storage is greater than 1000 litres, consideration shall be given to the installation of more than one cold water storage cistern. This will ensure adequacy of supply during maintenance or repair situations.

Large cold water storage cisterns over 1000 litres nominal capacity shall be provided with a washout pipe to facilitate drainage. Washout pipe connections shall be flush with the bottom of the cistern and to facilitate drainage it may be advantageous to install the cistern with a slight fall towards the washout connection.

4.5.2.6 Drinking water storage cisterns

While the preferred method of providing drinking water is from the incoming mains supply, it is permissible to provide drinking water from storage cisterns. Drinking water storage cisterns shall comply with the regulations pertaining to storage cisterns outlined above but the following shall also apply:

drinking water cisterns shall be fitted with a rigid air tight lid or cover that will not contaminate any condensate that may form on the underside. Every lid or cover shall be fitted with a vent and screened filter to prevent the entry of any contaminates;

drinking water cisterns shall also have a screened filter on the overflow pipe; and

drinking water cisterns shall be sized to hold 1 hour's supply of drinking water only.

4.5.3 Storage quantities, people and appliances

In the case of indirect cold water supply systems and direct systems where some appliances are fed from storage cisterns, consideration shall be given to the amount of stored water required. Storage requirements are often based on the provision of water when there is an interruption in supply or when the Local Authority mains supply pressure is low which can occur during peak demand times.

Before deciding on the quantity of stored water for any dwelling it is advisable to consult with the Local Authority and seek their guidance on this matter. As a general guide 80 litres per person or 100 litres per bedroom have been found to be satisfactory for most single occupancy dwellings. There are several guides that have been found to be useful in determining storage quantities such as BS 6700 and the Institute of Plumbing and Heating Design Guide.

4.5.4 Storage location

Cold water storage cisterns are normally located a high level in the roof spaces of dwellings. Consideration shall be given to the weight of the cistern when filled with water and adequate precautions shall be taken to ensure that cisterns are correctly supported.

The cistern location shall ensure that there is no danger of cisterns freezing or overheating.

In situations where cisterns are located below ground level adequate precautions shall be provided to ensure:

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that there is no ingress of water into the cistern from any source other than through the inlet control device; and

that any overflow or warning device is visible to ensure that there is no wastage of water

Underground cisterns shall also be securely bracketed to their base to ensure that there is no danger of them lifting in the case of water from another source (such as rainwater) surrounding them.

Adequate precautions shall be taken to detect leakage from underground cisterns.

4.5.5 Inter-connected cold water storage cisterns

To prevent the stagnation of cold water within cisterns it is essential that they are not oversized. Although it is recommended that the inter-connecting of storage cisterns be avoided, there may be circumstances where this is necessary such as in the case of large cold water storage cisterns (over 1000 litres). In such cases it is necessary to ensure that stagnation and contamination of stored water is avoided.

It may be useful to consider fitting cisterns in series rather than in parallel, which has been found to reduce the chances of stagnation of supply.

Another alternative that designers could consider is the use of split compartments within storage cisterns which can be useful in certain situations where an interruption of supply is unavoidable.

4.5.6 Legionnaires’ disease considerations

Legionnaires’ Disease is a type of pneumonia which is contracted by victims inhaling small droplets of water which have been contaminated by the bacteria Legionella Pneumophila. This bacterium is present in most water supplies, but in such low quantities that it rarely poses a threat to people. However, if the water temperature rises to 20oC the bacteria multiplies rapidly. For this reason it is essential that cold water storage cisterns and associated pipework are installed to ensure that these temperatures shall not be achieved within dwellings. It is recommended that pipes be insulated to prevent the water within them reaching 20oC.

In addition to the above the following precautions shall also be observed:

Stagnation of water in pipes and cisterns shall be avoided i.e. over sizing of cisterns is not recommended;

Terminal fittings that cause a spray should be avoided where ever possible; and

Materials that harbour or provide nutrient for Legionella bacteria and other organisms should be avoided.

While precautions to prevent the possibility of Legionella Pneumophila colonising plumbing systems shall be taken , there is no requirement under this standard for disinfecting single occupancy dwellings. However, those responsible for the design and installation of plumbing systems should make themselves aware of disinfection methods and good practice guides that can be followed. Further information in this regard is contained in the National Guidelines for the Control of Legionellosis in Ireland.

4.6 Cold water supply systems and fittings

4.6.1 Supplied from storage

In dwellings, except for a cold water outlet from the mains, hot and cold water shall be supplied to outlets via a cold water storage cistern.

4.6.2 Pumped systems

If the pressure from the mains is not sufficient to supply the needs of a building and the water supplier is unable to increase the pressure, consideration should be given to the use of a pumped system.

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The layout of a pumped system with regard to siting and selection of pumps and breaktanks should take into account the benefits of the existing mains supply pressure. Precautions must be taken to ensure that backflow from the distribution pipework and pump system back into the mains supply cannot occur.

4.6.3 Noise considerations and airlocks

4.6.3.1 General

Except for fire fighting installations and subject to appropriate regulations, all systems shall be designed and installed to ensure that noise generation is kept to a minimum.

To help prevent noise, pipework should be adequately supported and not come into direct contact with parts of the structure or other pipes, except for when it is fixed to the structure using appropriate brackets, if contact with the structure cannot be avoided then appropriate insulating pads should be used at the contact points. Pipework should not be fixed to light panels. .Further Guidance is available in BS 8233, Sound Insulation and Noise Reduction for Buildings Code of Practice.

Vibration is the usual source of noise from pipework and apart from being an annoyance; it can ultimately cause damage to pipework and fittings.

4.6.3.2 Water hammer

Water hammer is usually caused by the abrupt closing of a valve. It can also be caused by defective or incorrectly specified ball cocks and tap washers. The issue is made worse if the cold water supply pipework is not properly secured. Occasionally it can be cured by reducing the flow velocity in the pipework. Alternatively, appropriate shock absorbers may be fitted. Water hammer noise is exacerbated by inadequately supported pipework.

4.6.3.3 Flow velocity noise

At liquid velocities of over 3 metres per second pipework noise can become significant so steps should be taken to ensure that, while maintaining adequate flow, this velocity is not reached. This can be accomplished by increasing pipe diameter or fitting appropriate flow restrictors. Particularly for cisterns, splashing noise may also be an issue. Subject to water supplier approval, this may be tackled by ballcocks fitted with appropriate silence tubes that prevent reverse flow.

4.6.3.4 Expansion noise

Expansion noise comes from the expansion of the pipework system as it expands and contracts when it is thermally stressed. Care should be taken with brackets to ensure the pipework is free to move along its axis while still providing the required support. Adequate bracketing and pads between pipes and fittings and other surfaces should alleviate the problem. In long pipe runs, expansion can best be accommodated by expansion loops or propriety expansion joints.

4.6.3.5 Flow rate noise

Subject also to flow velocity recommendations in 4.6.3.3, the flow rate in small bore pipework should not exceed 1 litre per second.

4.6.3.6 Components

As it can be transmitted easily through the pipework system, noise and vibrations from pumps and other equipment connected to the system should be kept to a minimum. Official Regulations on maximum noise levels should be followed. Laboratory tests for such equipment are described in I.S. EN ISO 3822-1, I.S. EN ISO 3822-2, I.S. EN ISO 3822-3 and I.S. EN ISO 3822-4.

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4.6.3.7 Airlocks

All pipework should be fitted to prevent airlocks occurring. This can be accomplished by ensuring horizontal pipework is fitted with appropriate falls to allow air to escape naturally.

4.6.4 Materials

4.6.4.1 Choice of material

The following factors shall be taken into account in the selection of materials for use in water installations:

a) effect on water quality;

b) vibration, stress or settlement;

c) internal water pressure;

d) internal and external temperatures;

e) internal and external corrosion;

f) compatibility of different materials;

g) ageing, fatigue, durability and other mechanical factors; and

h) permeation.

Subject to the approval of the water supplier, it may be possible to use materials of a lesser durability for temporary installations.

The effect of the water itself on the materials should also be taken into account.

The pipework system shall be capable of tolerating without failure pressures in excess of 1.5 times the maximum pressure expected in operation. The system should also be able to withstand sustained temperatures of 40°C for cold water installations and 95°C for hot water installations. Hot water systems should also be capable of withstanding short term exposure to operating temperatures in excess of 100°C. Discharge pipes from temperature or pressure relief valves in unvented hot water systems should be capable of withstanding occasional exposure to hot water or steam at up to 114°C.

Care must be taken when joining pipes of dissimilar metals to prevent corrosion.

To prevent internal corrosion from adverse water quality, consideration should be given to pipework material selection or the use of an appropriate lining material. Similarly, where external corrosion is a concern (e.g. in buried pipework) a suitable coating or the use of corrosion resistant pipework material should be used. Where corrosion as a result of contact with soil is a concern, consideration should be given to performing a soil analysis and including the result in an appropriate material selection procedure. The local water supplier may be able to provide recommendations in such situations.

4.6.4.2 Lead

Lead should not be used in new installations, including in the jointing of pipes or in the repair of existing installations supplying drinking water. Care should be taken to ensure the continuation of electrical bonding when non-metallic pipe is used to replace lead sections. Further, pipework connected to lead installations should be protected against galvanic corrosion.

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4.6.4.3 Copper

Generally, copper is corrosion resistant and suitable for hot and cold water installations. In situations where there is evidence of corrosion potential for copper, water treatment or an alternative pipework material should be considered.

Copper tube shall conform to I.S. EN 1057 and copper tube jointing fittings must conform to I.S. EN 1254-1, I.S. EN 1254-2, I.S. EN 1254-3, I.S. EN 1254-4 and I.S. EN 1254-5. Solder used for joining copper shall be lead free.

Copper shall not be connected to other metals without the benefit of protection from galvanic corrosion. Where required; copper cylinders should be appropriately protected by protector rods (sacrificial anodes) or by an equally effective and approved system.

4.6.4.4 Copper alloys

Copper alloy in-line fittings shall conform to I.S. EN 1254-1, I.S. EN 1254-2, I.S. EN 1254-3, I.S. EN 1254-4 and I.S. EN 1254-5.

Fittings for use underground shall be dezincification resistant or immune. Compression fittings used must be type B fittings (manipulative) conforming to I.S. EN 1254-2.

Where it is already known that the water quality is such as to cause dezincification, fittings (except for draw-off fittings) manufactured from alloys subject to dezincification shall not be used. A test of dezincification resistance is given in I.S. EN ISO 6509. Fittings manufactured from grade A dezincification resistant brasses are marked with the symbol CR or "DRA".

4.6.4.5 Stainless steel

Stainless steel tubing shall conform to I.S. EN 10312. Joints between stainless steel and copper should be made with compression joints. Alternatively, stainless steel or copper capillary joints may be used. Regardless, stainless steel shall not be joined with soft solder. The joining of copper and stainless steel systems should be avoided if the copper section is significantly smaller.

Adhesive bonding should only be used where the water temperature will not exceed 85°C and must not be used underground, in a duct or in any other location where access is difficult.

4.6.4.6 Steel

Adequate corrosion protection should be used in situations where carbon steel is used. Medium grade steel tube in accordance with I.S. EN 10255 should be used for distributing pipes from storage cisterns. Pipes should be internally lined with an approved material and externally protected against corrosion when appropriate.

Galvanised steel tubes should only be joined by screwed joints. As they will affect the galvanizing, welded or braised joints must not be used. Where required; pre-formed bends should be used in preference to bending as they cause less surface damage.

4.6.4.7 Plastics

Care should be taken with plastic pipes exposed to temperatures above or below ambient. This applies to low as well as high temperatures, e.g. some plastic pipework materials become brittle at temperatures below 5°C. Pipes should not be installed near sources of detrimental heat. Plastic pipes used for hot water should be capable of functioning successfully at a temperature of 100°C at maximum pressure for one hour.

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4.6.4.7.1 General selection criteria and relevant standards:

Plastic pipe should conform to I.S. EN 1452-2 and any solvent cement used should conform to I.S. EN 14814. If used for drinking water purposes, pipes should conform to BS 4991.

Thermal expansion and contraction is more significant with plastic pipes and should be accommodated if the material selected is of sufficient rigidity to require it. Otherwise, most movement in softer plastic pipes is readily accommodated in standard installations.

In situations where it is difficult to make satisfactory solvent weld joints (e.g. underground or in confined locations), mechanical joints should be used. Dezincification resistant (or immune) copper alloy fittings should be used for mechanical joints. In other locations where there is adequate access and above ground, solvent welded joints may be used where possible.

Plastics used in float-operated valves should be in accordance with BS 1212-3 or BS 1212-4. Taps should conform to I.S. EN 200.

Care should be taken to ensure that the joints used to join different plastic pipework systems are compatible with both systems and are intended for the purpose.

4.6.4.7.2 Acetal

Fittings made from acetal are suitable for cold and most hot water applications. Jointing should be carried out by mechanical or push-fit methods.

4.6.4.7.3 Polybutylene (PB)

Pipes and fittings made from polybutylene (PB), conforming to BS 7291-1 and 2, are suitable for cold and hot water applications. The material is suitable where resistance to freezing temperatures and abrasion is required. PB cannot be solvent welded. Jointing by push-fit mechanical joints or by thermal fusion is suitable.

4.6.4.7.4 Polyethylene (PE)

The use and installation of polyethylene (PE) pipelines for the supply of drinking water should be in accordance with CP 312-3. Requirements for pipes are specified in I.S. EN 12201-2. Copper alloy compression fittings for use with PE pipe should be in accordance with I.S. EN 1254-3 and joints should conform to BS 5114. PE cold water storage cisterns in accordance with BS 4213 are suitable for storage and expansion purposes.

4.6.4.7.5 Propylene copolymer (PP)

Propylene copolymer (PP) cannot be solvent welded. Cold water storage cisterns in PP conforming to BS 4213 are suitable for storage and expansion purposes. Floats in PP for float-operated valves should conform to BS 2456.

4.6.4.7.6 Cross-linked polyethylene (PE-X)

Pipes and fittings made from cross-linked polyethylene (PE-X), conforming to BS 7291-1 and BS 7291-3, are suitable for cold and hot water applications. The material is particularly suitable when resistance to freezing temperatures and abrasion is required.

Jointing by mechanical or push-fit methods is suitable using fittings supplied for this purpose. These include fittings made from a plastics material that meet the applicable requirements of BS 7291, and copper and copper-alloy compression fittings conforming to I.S. EN 1254-2 and/or I.S. EN 1254-3.

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4.6.4.7.7 Un-plasticised poly vinyl chloride (PVC-U)

The use and installation of un-plasticised polyvinylchloride (PVC-U) pipes should be in accordance with I.S. EN 1452-2.

4.6.4.7.8 Acrylonitrile butadiene styrene (ABS)

Pipes and fittings made from acrylonitrile butadiene styrene (ABS) conforming to BS 5391-1or to I.S. EN ISO 15493 are suitable for cold water applications. Joining by solvent welding, screwed joints or unions are suitable.

4.6.4.8 Coating and lining materials

Recommendations and details for appropriate coatings for steel and iron pipes cisterns and fittings are contained in BS 5493. Clause 27 of BS 534 gives details on the internal protection of steel pipes.

4.6.4.9 Elastomeric materials

Elastomeric sealing rings in contact with drinking water shall conform to the requirements of types WA, WB or WE of I.S. EN 681-1.

4.6.5 Terminal fittings

4.6.5.1 General

In the absence of relevant European Technical Approval guidelines or CEN product standards, all components, materials and appliances used in potable water systems shall comply with National Standards or Local Regulations.

Sanitary taps shall conform to the relevant product standards and be provided with protection against backflow and back siphonage in accordance with I.S. EN 1717.

BS 6465-2 contains details on space requirements for WCs, WHBs, showers etc.

All dwellings shall have at least one bathroom. This must contain a bath or shower and a washbasin.

All dwellings must have a kitchen with an adequately sized sink and draining board.

I.S. EN 806-2 and I.S. EN 1717 shall be followed with regard to the installation of valves.

All basins, showers, bidets and sinks should be connected to the hot and cold water supplies.

Service valves conforming to BS 6675 should be fitted to the water supplies to all appliances. Adequate backflow protection steps as per I.S. EN 1717 shall be taken where there is a potential for it to occur but in particular with regard to appliances with flexible hoses.

The design and manner of installation of components e.g. sanitary taps with hoses and cold water appliances shall comply with the backflow protection requirements of I.S. EN 1717 (e.g. vending machines).

If not fitted securely to the appliance itself, taps should be fixed securely to an appropriate support to ensure there is no strain put on the pipework or any of its joints when the tap is operated.

Pipework should be configured to minimise any possible stagnation of water in unused sections.

Adequate drain points should be provided to ensure all pipework can be drained in an orderly fashion.

Where there is any possibility for confusion, hot water taps should be installed to the left of cold water taps.

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4.6.5.2 Flexible hoses

Flexible hoses on the supplies to appliances should not be longer than 2 metres and shall have a service valve at their upstream end. Flexible hoses should be designed for the task and comply with appropriate standards.

4.6.5.3 Water pressure

Water outlet fittings should be appropriate for the water supply pressure. In low water pressure situations (i.e. < 1 bar) appropriate low pressure fittings should be used. In situations where the water supplies are not of equal pressures, steps can be taken to either increase the lower supply pressure or reduce the higher supply pressure. Flow restrictors or other devices should be fitted to ensure that water outlets do not cause splashing.

4.6.5.4 Hygiene

Sanitary appliances should be designed and installed to ensure easy cleaning. This includes leaving adequate space around taps for maintenance as well as cleaning. In cases where greater hygiene is a necessity, overflows on sanitary appliances may be omitted.

4.6.5.5 Support

Appliances should be fitted securely to the building’s structure. The fixings support and structure to which the appliance is fitted should be capable of supporting it in normal use. All fixings should be of an appropriate material protected against corrosion. When appliances are fixed to floors or walls, they should be levelled as appropriate.

4.6.5.6 Waste outlets

Except for the appliances listed below, all baths, wash basins, sinks and similar appliances should have a fitted device that will allow the shutting off of the water outlet:

an appliance where only spray taps are provided;

a washing trough or wash basin where the waste outlet is incapable of accepting a plug and to which water is delivered at a rate not exceeding 0.06 litres per second exclusively from a fitting designed or adapted for that purpose;

a wash basin or washing trough fitted with self-closing taps;

a shower bath or shower tray;

a drinking water fountain or similar facility; or

an appliance which is used in medical, dental or veterinary premises and is designed or adapted for use with an unplugged outlet.

4.6.5.7 WCs

4.6.5.7.1 General

All WCs as well as their components should conform to relevant standards. This applies to new and replacement parts and products.

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4.6.5.7.2 Flushing

The flush volume from a flushing device used in a cistern should not exceed 6 litres whilst still clearing the bowl contents. Where dual flush cisterns are fitted, the lower flush volume should be capable of clearing the pan of urine and paper. Instructions should be permanently displayed on the use of a dual flush WC indicating how each flush is achieved.

In private dwellings pressure operated flush valves are not permitted.

Cisterns should have an indelible mark on the inside to show the maximum flush level and the quantity of water that will be flushed at that level.

All cisterns should be fitted with a warning pipe discharging in a conspicuous location, or an internal overflow discharging ultimately into the pan. If the latter, a strainer should be fitted upstream of the inlet valve to ensure any matter likely to affect the inlet valves operation are trapped before they cause a problem.

Alternatives to warning pipes include:

- a visible warning such as a tundish or electrically operated indicator lamp;

- an audible signal; or

- a device which detects the fault condition and shuts of the inlet valve

4.6.5.7.3 Filling

An air gap between the lowest level of a float operated valve and the maximum level of the cistern must be maintained. This is best done with a float operated valve that discharges upwards (though the discharge may immediately then be diverted downwards). A BS1212-1 conforming float operated valve should not be installed unless it is protected against backflow by an appropriate device just upstream of it. Float operated valves should be adjustable without having to bend the float arm.

4.6.5.7.4 Overflow/warning pipes

An overflow pipe discharging into the flush pipe may double as a warning pipe. An overflow/warning pipe should discharge at least 150mm above the ground level below it.

4.6.5.7.5 Cisterns

Pans for use with high-level cisterns (approximately 2m above floor level) should be constructed to cope with the extra force of the water discharging into it without splashing. Low-level- cisterns should be mounted such that their base is approximately 0.3m above the pan.

4.6.5.7.6 WC pans

Whilst conforming to relevant standards, WC pans should also be selected with regard to their outlet height in relation to drainage pipework. Wall hung pans should only be used where they can be attached to adequate supports capable of carrying the load while they are in use. If squatting pans are selected, the squatting plate should be a part of the pan or designed to work with that pan.

4.6.5.7.7 WC seats

WC seats and covers should be smooth (no ribs or recesses) and impermeable. Hinges should be in accordance with BS 1524 and constructed of an appropriate material given their intended use (public/domestic). While ring seats are the most common style, open fronted seats are available but they are not suitable for use by disabled people.

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4.6.5.8 Baths

Baths should conform to:

BS 1189 for baths made from porcelain enamelled cast iron;

BS 1390 for baths made from vitreous enamelled sheet steel;

I.S. EN 198 for baths made from acrylic material;

I.S. 232 for the connecting dimensions of all baths;

I.S. EN 12764 for whirlpool baths; and

I.S. EN 60335-2-60 for whirlpool and other pumped baths.

Other baths are available for use by ambulant disabled people and attention is drawn to the various organisations which specialize in equipment for the elderly. A bath should have a bottom with a fall to the outlet. Where high bath sides are a problem, devices to assist the bather to enter and leave the bath, e.g. grab rails, should be considered. Baths with removable or hinged sides are available but bathers have to sit in the bath whilst it is filling and emptying, which will increase bathing time.

A sitz bath which is a bath with a stepped bottom to form a seat can be used where floor space is restricted.

Baths should conform to the relevant standard for their style and/or material (e.g. acrylic, steel, whirlpool). The bottom of the bath should fall towards the outlet.

4.6.5.9 Showers

A shower lends itself to more economical use than a bath. The type of shower (power, electric, gravity etc) should be selected with regard to the characteristics of the water supply available in the dwelling. Shower enclosures should conform to I.S. EN 14428 and shower trays and their installation should conform to the relevant parts of BS 6340 and I.S. EN 251. Wet room style installations may be used where level access is required to the shower.

4.6.5.10 Bidets

Over rim supply bidets may be floor mounted or wall hung. They should conform to BS 5505-3 and I.S. EN 14528 and should have connecting dimensions in accordance with I.S. EN 35 and I.S. EN 36.

The bidet itself may be of an over-rim supply or a below rim (i.e. rising spray – these include a flexible hose).

4.6.5.11 Sinks and drainers

Domestic sinks should be fitted with a drainer that drains towards the sink. Preferably there should be raised edges on three sides of the drainer to prevent spillage. Sinks should conform to the relevant standard depending on their construction material, and their connecting dimensions should comply with I.S. EN 695.

4.6.5.12 Urinals

4.6.5.12.1 Bowl urinals

Vitreous china bowl urinals should conform to BS 5520. Bowl urinals should be used where floor movement may occur.

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4.6.5.12.2 Slab urinals

Slab urinals made from Stainless Steel should conform to BS 4880-1. The ends of slab urinals should be returned (project perpendicular to the slab) in the same material as the slab. The outlet should be fitted with a trap accessible for cleaning. The whole of the usable surface of the slab should be flushed via sparge pipes or individual spreaders via a cistern (the latter preferably concealed).

4.6.5.12.3 Stall urinals

The full surface likely to be fouled in a stall urinal should be flushed by a spreader arrangement.

4.6.5.12.4 Trough urinals

For trough urinals, the back of the urinal should extend at least 450mm above the front lip. Flushing should be by sparge pipe or spreader.

4.6.5.12.5 Waterless urinals

Waterless urinals may either be installed as complete units or the relevant parts fitted to existing slab or bowl urinal installations. They do not need a permanent water connection although they may require regular wet cleaning. They may require specific regular maintenance (‘serviced’ waterless urinals) or they may not (‘non-serviced’ waterless urinals). Serviced urinals may contain components for pipe deposit suppression and removal, odour suppression and/or urine drainage improvement from walls. Due to these elements, the substances involved and their maintenance regime, they are often rented or hired with a service contract. Air flushed urinals use a fan to generate a ‘flushing’ airflow.

4.6.5.12.6 Flushing

Unless a urinal is flushed by a means dependant on the amount of use it gets (e.g. manually flushed by the user or, via an automatic system that detects use), the flow into the flushing cistern should be controlled via a time-switch set to regulate the water supply dependent on normal use schedules. For manually flushed or automatically operated flushing mechanisms, the flush volume should be less than 1.5 litres per flush. For flushing systems that are not operated according to use, the flushing cistern in a single urinal bowl installation should provide a flush of 10 litres per hour. In the case of an installation consisting of multiple urinals, 7.5 litres per hour should be flushed per urinal bowl or position 700mm width of slab.

If a pressure flushing system is used, suitable backflow prevention should be installed appropriate to fluid category 5.

4.6.5.13 Washbasin, wash fountains and washing troughs

Washbasins and hand rinse basins should comply with the appropriate standards. The connecting dimensions of the different styles (pedestal, semi-pedestal etc.) should comply with I.S. EN 31 or I.S. EN 32.

Washing fountains and troughs should comply with I.S. EN 14296 and be fitted such that the top of the rim is approximately 900mm above floor level. They should supply temperature-controlled water through spray outlets.

4.6.5.14 Drinking water dispensers

Drinking water dispensers may be mains fed, bottle fed, vending machines or cup filling water dispensers.

4.6.5.15 Drinking fountains

The nozzle of drinking fountains should terminate at least 25mm above the spill-over level of the fountain. The nozzle should be shielded to protect it from contamination in normal usage. They may be either wall or floor mounted.

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4.6.5.16 Waste disposal units

In domestic situations, waste disposal units fitted to kitchen sink outlets are normally either ‘batch fed’ or ‘continuous fed’

4.6.5.17 Water taps

Drinking water should be made available in every dwelling. In domestic situations this is normally at the sink in the kitchen. No potable water draw-off point should be located at the end of a long pipe run if that pipework is not used regularly. Taps supplying drinking water should be fed from a wholesome source, preferably directly of the supply pipe. If it is not possible to draw water directly from the supply pipe, then drinking water may be supplied from an appropriately designed and installed cistern containing wholesome water. In situations where the water pressure from the supply pipe is insufficient and the demand is less than 0.2litres per second, then water may be pumped directly from the supply pipe. If the demand is greater than 0.2 litres per second then the approval of the water supplier must be sought.

Care should be taken to ensure that water from a water softener intended for drinking purposes should be wholesome.

Care should be taken with pipe layouts to ensure that cold water pipes are not routed through airing cupboards and that they should not closely follow the route of hot water or heating pipes. If appropriate routing is not possible, hot and cold water pipes should be insulated where they could affect each other.

Wash basins in rooms containing a WC should have both hot and cold water supplies piped to them.

4.6.5.18 Washing machines, dishwashers, and other appliances

Clothes washing machines, clothes washer-driers and dishwashers must be economical in the use of water. The following should be considered a maximum per cycle for domestic machines:

washing machines, 12 litres per kilogram of wash-load for a standard 60°C cotton cycle;

washer-driers, 48 litres per kilogram of wash-load for a standard 60°C cotton cycle; and

dishwashers, 4.5 litres per place setting.

4.6.5.19 Water for outside use

Water for animal or poultry drinking purposes should be delivered through an effective device to control the quantity of water delivered (e.g. a float valve). Care should be taken that the pipework and its components are protected from damage and contamination. Appropriate steps shall be taken to prevent contamination of the water supply. A service valve should be fitted as appropriate.

Ponds, fountains and pools should be leak free.

4.6.6 Water conservation

4.6.6.1 General

The designer of a water supply system should seek to minimize water usage while still achieving adequate system performance. BS 6465-1 gives guidance on the selection of sanitary appliances and installations

4.6.6.2 Leakage

The discharge end of warning and overflow pipes should be in a conspicuous area.

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4.6.6.3 WC flushing

The flush volume in a WC is often related to the design of the pan so care should be taken when adjusting flush volumes to ensure that the WC operates as it should. A single flush flushing mechanism and the larger flush of a dual flush mechanism should discharge no more than 6 litres into the pan.

4.6.6.4 Urinal flushing

Flushing volumes and frequencies are outlined in clause 4.6.5.12.6. If flushing is not usage driven, a mechanism to cut off the water supply during periods when the urinals are not expected to be used should be employed.

4.6.6.5 Waste plugs

Waste outlets from washbasins, sinks, baths (except for shower baths or shower trays) and similar appliances should be provided with an effective plug. Exceptions to the net for a waste plug are where the supply to the appliance is limited to less than 3.6 litres per minute, is fitted with a self-closing tap or the appliance is for medical dental/veterinary use.

4.6.6.6 Self-closing taps

Self-closing taps shall conform to I.S. EN 816 and be capable of closing against the system pressure without leakage. However, they should only be used in situations where regular inspection and maintenance is enforced.

4.6.6.7 Washing troughs and fountains

Fittings delivering water in washing troughs and fountains should be capable of supplying each position (600mm of edge space) independently.

4.6.6.8 Spray taps and aerators

Spray taps should only be used for hand-rinsing applications as heavy washing will usually require a greater quantity of water. The water flow may not be sufficient to keep the wet area of the appliance clean. Care should be taken, particularly in hard water areas, to ensure the spray head is regularly cleaned to prevent blockages. Before fitting either aerators (which should conform to I.S. EN 246) or spray taps, it must be ensured that the water flow and pressure is sufficient to allow them to work correctly.

4.6.7 Meters

4.6.7.1 General

In certain water supplier areas it is a requirement that any mains water service to commercial premises must be metered.

A commercial premise means any business type premises such as factory, store, office and also includes the likes of B&Bs or, even where a person is working from home there will be a requirement for a meter or for a fixed charge taken into account the type of commercial activity. Metering may soon be a requirement for domestic buildings.

Meters on the incoming supply to premises, for revenue charging purposes, are usually supplied and installed by the water supplier and sited by agreement between the consumer and the water supplier.

Wherever possible meters should be installed at or near the street boundary of the premises supplied, which is the limit of the responsibility of the water supplier for maintenance of the service pipe.

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The meter should be protected from the risk of damage by shock, vibration or frost induced by the surroundings at the place of installation.

4.6.7.2 Meters

Meters shall conform to I.S. EN 14154-1, with suitable connectors to facilitate future meter changes without the use of heat or major disturbance of the pipework. Meters shall be installed as per the requirements of I.S. EN 14154-2.

4.6.7.3 Bonding

To protect the installer against electrical fault and for maintenance of the earth connection on both internal and external installations, a copper bonding conductor of at least 10mm2 shall be installed for bonding between inlet and outlet pipework connections to water meters, water suppliers' stop-valves or other water conveying components in a metal water supply pipe to ensure electrical continuity to any pipework temporarily disconnected for the purpose of removing such components for replacement or maintenance. The copper bond shall be connected prior to attaching the pipework and shall remain in place following installation.

4.6.7.4 External installations

In external meter installations, the meter shall be installed below ground in a position accessible for meter reading and changing, with the dial uppermost. The chamber shall be fitted with a cover marked "water meter", of sufficient strength to carry the loads to which it might be subjected and fitted with slots or lifting eyes. Pipes or drains other than the meter pipework shall not pass through the meter chamber. The chamber shall be sized so that there is ample space available for removing the meter using the necessary hand tools. Space shall be left for the extraction of bolts from flanges for ready dismantling of joints and no part of the meter assembly shall be built into the walls of the chamber or concreted into the chamber. The pipe on both sides of the meter assembly shall have a clearance space around it through the wall of the chamber to facilitate exchange of the meter.

Where the chamber needs to be watertight, the clearance shall be fitted with a sealing material approved by the water supplier and sufficient length of pipe left inside the pit to facilitate meter exchange.

Pipework on both sides of the meter assembly shall be firmly fixed to prevent movement of any flexible joints within the meter assembly. Nevertheless, such anchorage shall leave sufficient room for connecting and disconnecting the meter making use of the adaptors provided. The meter shall also be supported on the underside so as not to create differential loads between the meter and its connecting pipework. There shall be a valve which isolates the meter on both the inlet and the outlet.

Any stop-valve in a meter chamber shall conform to Table 2 of BS 6700.

For housing and other installations where the maximum water requirement does not exceed 3500 l/h, the chamber may be constructed of glass reinforced plastics or PVC (see Figure 2). For meters where the water flow exceeds 3500 l/h, the chamber should be constructed of brick or concrete. The clear opening of the surface box should be the same as the internal dimensions of the chamber. Steel framed, concrete fitted covers to chambers are not recommended on account of their weight and their liability to flex causing the concrete to crack and the cover to jam.

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Figure 2 — External meter installation

4.6.7.5 Internal meters

Internal meters shall be fixed horizontally or vertically and with the dial not more than 1.5m above floor level and readily visible for reading. Where the existing pipework is, or can be, re-positioned so as to be parallel to the wall and is not less than 50mm away from it, installations shall be as indicated in Figure 3. Where a consumer wishes to limit access to the meter for reading purposes, a remote readout device may be installed if the water supplier agrees. Pipework shall be adequately supported, leaving sufficient room for changing the meter with the connections provided.

The meter shall be installed downstream of the internal stop-valve and as close to it as possible. Where a drain valve is required, it shall be installed immediately downstream of the meter. The length of pipe between the stop-valve and the meter cannot easily be drained and will thus require effective protection against damage from frost. A second stop-valve or servicing valve shall be installed downstream of the meter. Where the installation of meters in exposed locations, e.g. garages subject to frost, is unavoidable and agreed by the water supplier, adequate insulation shall be provided but not so as to seriously impede reading or changing the meter.

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Key

1 Approved electrical continuity bond 2 Outlet stop valve 3 Direction of flow 4 Drain-valve on outlet of meter (moved if necessary) 5 Straight connectors 6 Incoming stop valve 7 Floor

Figure 3 — Recommended meter installation inside buildings

4.6.7.6 Non-revenue meters

The installation of non-revenue meters shall conform to 4.6.7 except that the water supplier need not be consulted.

4.7 Reclaimed water systems

Reclaimed water systems can help to reduce the consumption of mains water and also the loading on the drainage system. Extreme care shall be taken from a health and safety perspective to ensure that there is no risk presented by the use of reclaimed water in place of a mains delivered supply.

4.7.1 Protection of potable water supply

The presence of a reclaimed water system (RWS) should not result in the excessive consumption, misuse or waste of the mains water supply. It is critical that all necessary steps (backflow prevention etc.) are taken to prevent the possibility of cross contamination between reclaimed water systems and the mains water supply.

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A mains water supply to a cistern containing rainwater or grey water must be protected by an appropriate air gap. For further information on the protection of potable water installations from pollution and backflow, refer to EN 1717.

Pipes or fittings containing rainwater, grey water or reclaimed water must not be cross connected with those supplying potable water. All components in a RWS used for grey water, rainwater or reclaimed water must be clearly labelled and only used for that purpose. Water from a RWS shall not be used for drinking, cooking or bathing unless the system design, installation and maintenance, as well as appropriate water quality monitoring, complies with potable water standards and regulations.

As Class B water may lead to a shorter life of system components resulting in leaks and drips, regular maintenance is required to ensure that the failure of these components does not place an undue burden on the topping-up of the RWS by the mains water supply. Where the RWS is pressurised at the discharge side, such as when appliances are fed directly from a pump or sealed pressurised system, thought may be given to keeping the system pressure below that of the mains water pressure. Though insufficient in itself, this will provide some extra protection against backflow.

4.7.2 Contamination of reclaimed water

Pipework should not be placed in ground that is likely to be or has been contaminated by faecal matter. Care should similarly be taken in the choice of materials used when laying pipes in ground that has been contaminated by corrosive materials to ensure the integrity of the pipework is maintained.

Fittings pipework and other materials should be selected to ensure that they do not negatively affect the quality of the reclaimed water.

Kitchens should generally be avoided as a source for reclaimed water. For example, water previously used for washing cooking utensils will contain fats, oils and grease. If these accumulate in a reclaimed water system they have the potential to create blockages and unpleasant odours. As a result, this water will require a good deal of special treatment.

Rainwater collected from roofs will contain an amount of atmospheric and environmental pollutants as well as contaminants collected when it comes in contact with the surface it is collected from such as bird and animal faeces. Similarly, rainwater collected from areas used by vehicles may also contain hydrocarbon contaminants.

As well as biological components, water reclaimed from washing processes (baths, washing machines, WHBs, showers etc.) will contain various amounts of chemicals as a result of the detergents and other cleaning products used. Given the unpredictability of the quantity of these chemicals in the reclaimed water, careful measurement and compensation for their presence shall be made in the RWS.

Where water is stored in locations where it is subject to warmth, the potential for organism growth is greatly increased. Appropriate insulation of the system components will help to tackle this as well as providing protection from freezing.

Special attention should be paid to the turnover rate of the water in the system. Situations where water is left standing for longer than one week should be avoided and the storage of untreated reclaimed water should be kept to a minimum.

Appropriate measures should be taken to prevent the ingress of any contaminants while the reclaimed water is inside the RWS. This may include the use of covers, screens on all inlets and outlets, and the selection of suitable components so that light is excluded.

The appropriate regulations must be followed if underground tanks are to be installed as part of the collection or storage system.

Water sources potentially contaminated with faeces, such as WCs and bidets, should not be used in a RWS. Water from baths and other personal washing appliances should only be used if it is treated with a view to it being potentially contaminated with faeces. Grey water sources should be fed through a separate vented

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waste stack to ensure it doesn’t come into contact with WC or any other unsuitable sources of waste. Bypass facilities should be provided to redirect any unintentionally contaminated water sources to the sewer system.

The quality of reclaimed water used for irrigation purposes must not be such as to potentially contaminate the vegetation, land or watercourses it comes in contact with.

4.7.3 Design considerations

The sizing of components used in a RWS should be based on the quantity of water that will be collected.

Approximately two thirds of water used domestically can be classed as grey water.

Filters, storage cisterns and treatment systems should be adequately specified given the expected volumes. Capacity control should be provided for by overflow arrangements that will discharge appropriately.

Water collected and stored at a high level can potentially be used as a gravity fed source for appropriate domestic uses. Where reclaimed water is stored at a low level, a pump will be required to supply a high level storage tank or to feed the appliances directly. Tanks should be located in well ventilated areas so that any potentially harmful gases produced (such as from disinfectants) will be readily dispersed.

Provision must be made in critical systems for using mains water supply as a source in the event of reclaimed water not being available. The mains water supply should be appropriately protected by using suitable backflow prevention methods (e.g. an air gap) and, if it is feeding a storage cistern, a suitably positioned overflow/warning pipe arrangement.

Filters will be required on all types of RWSs regardless of their water source. Rainwater fed systems should have their filters placed before the storage tank to ensure no organic debris (such as leaves) are allowed into the tank to enhance its attractiveness to bacteria. Filtration systems should have an appropriate maintenance schedule to prevent failure through perforation of the filter material, odours, health concerns and blockages.

Steps should be taken in the design of the system to encourage as much aeration of the stored water as possible. This may include feeding the collected water into the storage tank at a low level though not in such a way as to aggravate any settlement of solids that may have taken place at the bottom of the tank. Water from storage tanks should be drawn off as close to the surface as possible to ensure the cleanest water gets used first. This may be accomplished by using a floating inlet to the discharge pump. Tanks using rainwater as their source should have their overflow pipes discharging into the surface water drain. Those using grey water as their source should have their overflow pipes discharging into the foul water drain. The connection of storage tanks to underground drains should be done so as to ensure that a blockage in the underground drain will not force the drain’s contents back into the tank.

The RWS should be easy to operate and be designed such that maintenance and cleaning can be carried out easily and thoroughly. The eventual owners and users of the system should be provided with appropriate and clear operating, maintenance and safety instructions for their system. Adequate records of maintenance and cleaning events should be kept. Appliances supplied with reclaimed water should be clearly labelled to that effect. Appliances served by a Class B reclaimed water system should display appropriate warnings for use.

Given the potential for corrosive elements from dissolved salts or treatment chemicals in all sources of reclaimed water, the material used in pipework and fittings should be chosen with care. Pipes and components should be clearly marked to indicate that they contain reclaimed water. Steps should be taken to prevent accidental consumption of the water.

4.7.4 Reclaimed water treatment

The most basic treatment of all reclaimed water is through settlement and filtration. Chemical dosing without these stages in place will be ineffective at least and potentially dangerous. An allowance should be made in the specification of storage/settlement cisterns for the space taken up by accumulated settled solids. Access for cleaning and flushing will also be required.

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Filters used should be appropriate for the task and not contain biodegradable components.

A sample point for checking compliance to the relevant standards should be provided at a location where the treated reclaimed water is stored.

Health and safety regulations should be followed with the use, handling and storing of treatment chemicals. The treatment system should be configured to shut down the supply of water from the storage tank if the treatment fails in any way, for example, if the treatment chemicals run out in an automatic dosing situation.

In the event of insufficient turnover of stored reclaimed water, consideration should be given to discharging the entire contents of the system. Given the potential for overflow, chemical treatment in rainwater sourced systems should be avoided in favour of UV treatment. UV treatment may be used for grey water sourced systems provided the water has been appropriately conditioned to ensure its clarity.

4.7.5 Reclaimed water uses

The chief uses for reclaimed water are; toilet flushing, non-edible crop irrigation, garden watering and certain washing processes.

Rainwater or grey-water should not be used in aerosol generating systems (such as sprinklers used in irrigation and high pressure hoses for washing) without first having been treated and, if necessary, disinfected. This is to prevent human contamination through the inhalation of the aerosols produced.

Filtered rainwater collected from clean surfaces may be used directly for toilet flushing, non-sprinkler garden watering and car washing.

4.8 Commissioning and handover

4.9 Schedule of maintenance

On installation customer to be informed of a written schedule of maintenance.

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5 Hot water supply systems

5.1 General

Hot water services shall be designed to provide hot water at the point of use, in the quantities and at the temperatures required by the user.

5.2 Types of systems

There are a number of choices of hot water supply systems:

vented direct hot water storage cylinder;

vented indirect hot water storage cylinder;

unvented hot water storage cylinder (unit);

central heating combination boiler incorporating unvented hot water storage unit; and

central heating combination boiler incorporating instantaneous hot water supply facility;

Except for water supplies to dual stream fittings, mixing fittings should be supplied with comparable hot and cold water supply pressures.

5.2.1 Storage

Water installations in most local authority areas in the ROI are of the indirect type. This means that hot water storage vessels or other water heaters should be supplied with water from a suitably installed water storage cistern and not directly from the mains water service pipe.

Installers shall contact their relevant local authority regarding approval of any water installation prior to commencement of work.

5.2.2 Vented

Vented hot water storage cylinders are supplied with cold water from a cold-water storage (cws) cistern, which is situated above the highest outlet to provide the necessary head pressure in the system and which accommodates expansion of the water when it is heated.

An open vent pipe runs from the top of the hot water storage vessel to a point above the water storage cistern, into which it is arranged to vent.

Explosion protection involving no mechanical devices is provided by the open vent and the cws cistern.

Refer to I.S. 161.

5.2.3 Unvented

Unvented systems in the ROI are supplied from cold water storage cisterns, either directly or through a booster pump.

The main characteristics of unvented hot water storage systems are:

Explosion protection is provided by safety devices;

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Systems depend upon pressure continuity and the hot water flow cannot be guaranteed if water supply pressures reduce or fail.

5.3 Design criteria

5.3.1 Secondary distribution systems

In hot water systems incorporating a hot water storage vessel, the hot water supply or distributing pipe shall be arranged to be from the top of the vessel or as near thereto as practicable and always above any primary flow connection.

Secondary hot water systems should be supplied from a cold water storage cistern. Both vented and unvented hot water storage systems can be supplied by gravity from a cold water storage cistern, unvented hot water storage cisterns can be supplied with water from a boosted supply, either supplied from overhead water storage or from a suitably installed break water storage cistern. The water supply to unvented hot water storage can also be supplied from the mains water service pipe if the local water authority allows such connection. Booster or mains water direct connection to unvented hot water storage should be suitably regulated by the fitting of a pressure reducing valve.

To promote maximum economy of fuel and water the hot water distribution system should be designed so that water appears shortly after the taps are opened. To this end terminal branches should be as short as possible. The hot water branch pipe supplying spray taps for hand washing should not exceed one metre in length.

When delivery points are situated at a distance from the water heater or hot water storage vessel, consideration should be given to the use of a separate water heater installed closer to those delivery points or to insulating and electrically trace heating the flow pipe work.

As an alternative a secondary circuit with flow and return pipes to the storage vessel could be considered but secondary circuits inevitably dissipate heat and should be avoided where possible. The return pipe should be connected to the hot water storage vessel at a point not lower than the level of the boiler flow pipe connections if there is one. Refer to section 5.4.

5.3.2 System components

5.3.3 Open vent pipe

The vent pipe from a storage type hot water system shall be taken from the top of the storage vessel or the highest point of the distribution pipe-work to a point above the cold feed cistern. An offset shall be included in the vent pipe close to its point of connection to the hot water storage vessel.

When a vented primary circuit is used in an indirect system, unless a single feed hot water storage cylinder is used, the vent pipe shall run from the highest of the primary circuit to a point above the primary feed and expansion cistern at a height that will prevent a discharge of water from vent pipe and /or air entrainment into the system under normal working conditions. Due allowance shall be made for the head induced by any circulating pump used, refer to I.S. EN 12828.

Gravity circulation systems are not recommended, but if used the height shall be not less than 150 mm plus 40 mm for every metre in the height of the overflow level above the lowest point of the cold feed pipe.

No valves shall be fitted to any vent pipe and the pipe shall rise continuously from it's point of connection, to the hot water system, to it's end, except where it is permitted to be bent so as to terminate downwards. Vent pipes shall not be less than 19 mm bore.

One pipe shall not serve as both vent pipe and cold feed pipe, unless the associated system or circuit has:

the energy supply to each heater under thermostatic control;

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the energy supply to each heater fitted with a temperature-operated manual reset

energy cut-out independent of the thermostatic control; and

a temperature relief valve in accordance with BS 6283-2, or a combined temperature and pressure relief valve in accordance with I.S. EN 1490, e.g. as required by I.S. EN 12897 and I.S. EN 60335-2-21.

5.3.4 Circulating pump

Inlet and outlet connections to a circulating pump shall be fitted with full-way valves.

The circulating pump shall be installed in accordance with the manufacture’s recommendations and space shall be allowed for maintenance and removal.

Circulating pumps shall conform to I.S. EN 1151-1 and I.S. EN 60336-2-51.

5.3.5 Valves and taps

Valves used for isolating a section of the water service shall not leak when closed.

Sufficient draining taps conforming to BS 2879 shall be fitted in accessible positions for draining the entire system.

Mixing valves (whether thermostatically controlled or not) and single outlet combination taps for mixing hot water and cold water and discharging the mixture shall be supplied with cold water from the same source, e.g. storage cistern or mains service, that feeds the hot water system.

Except for bath/shower single units, manually operated non-thermostatically controlled mixing valves shall not be used to control the water to more than one outlet.

The requirement for mixing valves is especially important with showers and spray fittings.

Anti-scald systems shall be installed, refer to sections 5.6.1 and 8.2.1.4. The UK Health and Safety Executive guidance document, 'Health & Safety in Care Homes, HSG 220', offers guidance on how to maintain water at a safe temperature to prevent scalding.

5.3.6 Storage vessels

Hot water storage vessels shall conform to BS 853-1, BS 1566-1 and BS 1566-2, BS 3198 or I.S. EN 12897, as appropriate.

It is recognised that special copper cylinders, which are not covered by Irish Standards, might be required where standard cylinders will not fit. The primary heaters in these cylinders should conform to BS 1566-1 (open vented) and BS 1566-2 (single feed). Refer to section 5.3.10.

For installation of combination cylinders refer to BS 3198.

Apart from pressure considerations, the grade (wall thickness) of copper storage vessels and also the need for protector rods, should be determined on the basis of the type of water supplied in the area. If necessary, the water supplier’s advice should be sought.

The anode attachment and contact regions should be protected either by the use of PVC sleeving or epoxy resin coatings.

Protector rods (sacrificial anodes) should be fitted to cylinders during manufacture. Pitting corrosion is more likely where there is hard or moderately hard deep-well water. It is recommended to fit a cylinder that has a manufacturer’s fitted temperature sleeve. If none is fitted then care should be taken not to breach the insulation on the cylinder when installing.

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NOTE Protector rods (sacrifical anodes) BS 1566, no longer includes a specification for the construction of a sacrificial anode but prefers a corrosion resistant construction approach to the cylinder retaining a temperature of 40°C minimum to the base of the cylinder after reheat. This approach has proven most effective and removes any adverse comment regarding the usage of aluminium in potable water storage.

In the construction of mild steel cylinders with either glass or enamelled linings some manufacturers still supply Replacable Anodes.

5.3.7 Electric immersion heaters for storage vessels

The immersion heater or heaters shall conform to IS EN 60335-2-21 and all electrical controls shall conform to the relevant clauses of IS EN 60730-2.

The immersion heater shall be provided with a non-self-resetting thermal energy cut-out device in addition to the normal automatic thermostat.

Immersion heaters and controls shall be so located that insertion, removal and adjustment can easily be performed.

5.3.8 Miscellaneous

The cold feed pipe to the hot water storage vessel or water heater shall be sized appropriately. It shall discharge near the bottom of the heater or storage vessel and, if the system is cistern supplied, the cold feed pipe shall not supply any other fitting. A separate cold feed pipe from a separate expansion cistern shall be provided to the lowest point of a vented primary circuit in an indirect system unless a single feed hot water cylinder is used.

A servicing valve, or stop-valve with a fixed washer plate, or a no less effective valve shall be provided in a convenient and accessible position in every cold feed pipe other than those to a vented primary circuit which shall have a valve only when the capacity of the expansion cistern exceeds 18 l.

In direct type boiler systems the cold feed pipe and the return pipe to the boiler shall have their own connections to the hot water storage vessel.

5.3.9 Supplementary water heating and independent summer water heating

Where supplementary electric heating is to be used in conjunction with a boiler, the height of the storage vessel above the boiler shall not be less than one metre in order to prevent circulation of hot water from the storage vessel to the boiler.

It is permissible for supplementary water heating and independent summer water heating to be provided in the storage vessel by an electric immersion heater, a gas-fired circulator, a heat pump or from solar energy.

Supplementary hot water may also be provided in the form of a single point gas or electric heater at the point of use.

5.3.10 Storage quantities required

Where the user requirements are not specified, and in particular where the user is not known, e.g. in housing developments, an assessment of user needs shall be made on the basis of the size and type of building/premises and of experience and convention.

Where a dwelling has only one bathroom it shall be assumed that immediately after filling a bath, some hot water will be required for kitchen use, but a second bath will not be required within 20 to 30 minutes. Where a dwelling has two or more bathrooms or additional en-suite showers it shall be assumed that all installed baths or showers will be used in succession and that hot water will immediately be required for kitchen use. Suitable hot water storage or capability shall be provided for such use.

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The amount of hot water to be stored shall be related to the likely consumption and recovery rate. In dwellings, the storage capacity should normally be based on 45 l per occupant unless pumped primary circuits or special appliance justify the use of smaller storage capacities. A minimum hot water storage capacity of 100 should be used in solid fuel fired boiler hot water systems.

5.3.11 Legionnaires disease considerations

Legionella pneumophilia is the agent that causes legionnaires’ disease (LD). People catch LD by inhaling droplets of water suspended in the air, which contain the bacteria.

In order to reduce the risk of colonisation of a water system the temperature of cold water in pipes and cisterns should not exceed 20°C. Hot water should be stored and distributed at a temperature of not less than 60°C with a temperature at the discharge point of 50°C after one minute.

Cold and hot water pipe work should be as short as is practicable; especially where it only serves infrequently used taps and fittings. In all cases, minimum hot and maximum cold water temperatures should be reached at all draw off points after a maximum period of one minute running at full flow. Due consideration should be given to the selection of braided or flexible hoses and the suitability of materials on contact with water.

Measures shall be taken in the design and installation of cold and hot water systems to prevent the colonization of the system with legionella. These shall include the avoidance of:

stagnation of water in pipes, cisterns and other storage vessels;

water temperatures in the range of 20°C to 45°C;

use of materials that can harbour or provide nutrient for bacteria and other organisms, inside cisterns;

installation of fittings where there is a potential for aerosol formation.

5.3.12 Energy and system efficiency

Except for systems where water is heated by a source that itself is incapable of raising the temperature above 100°C, or for instantaneous electric water heaters with a capacity of 15 litres or less that are fitted with a CE mark, or for instantaneous gas water heaters with a capacity of 15 litres or less that are fitted with a CE mark or conform to I.S. EN 26 as appropriate, wherever stored-water is heated, the following conditions apply:

The hot water storage vessels should be thermally insulated either by factory applied thermal insulation in accordance with BS 1566-1 and BS 1566-2 or BS 3198, as appropriate, and in accordance with the relevant Building Regulations.

Where a segmented insulating jacket is used, the segments of the jacket shall be taped together to provide a complete insulation cover for the storage vessel.

5.3.13 Cold water supply

Feed cisterns, expansion cisterns, combined feed and expansion cisterns and expansion vessels shall conform to BS 417-2, BS 4213, BS 4814 or BS 6144, as appropriate.

A cistern used only to feed the hot water supply system shall conform to all the requirements for a cold water storage cistern. It shall have a capacity at least equal to that of the hot water cylinder. The feed cistern shall be situated at a height that will ensure a satisfactory flow of water at the highest point of discharge.

If there is a cold water storage cistern that supplies cold water to delivery points and this is also used as the feed cistern for a direct system, or for the secondary part of an indirect system, it shall have a capacity of at least 230 litres.

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The feed and expansion cistern for the primary circuit of an indirect system shall be used only for that circuit and shall be able to accommodate the expansion of the water in the circuit if raised to boiling point. The increase in volume shall be taken as 4% of the volume of the water in the circuit. The float-operated valve in an expansion cistern for a primary circuit shall incorporate adequate backflow protection or shall conform to BS 1212-2 or BS 1212-3 and be installed at a level no lower than that of the warning pipe for fluid category 3 installations. The valve shall be adjusted to close when the water is cold at a level low enough to ensure that expansion on heating does not cause the water to rise higher that 25 m below the over-flowing level of the warning pipe. The float shall be of a material suitable for use in hot water at a temperature of 100°C.

No warning or overflow pipe from any cistern connected to a primary circuit shall be installed to convey water to any cistern from which water might be drawn for any domestic purpose.

The use of float operated valves incorporating a drop lever is the preferred method of controlling a low lever of water in the feed and expansion cistern to a primary circuit.

Where the cold water cistern supplying water to a vented hot water storage vessel is also used to supply drinking water to sanitary or other appliances, any expansion water entering the cistern through the feed pipe should preferably not raise the temperature of the drinking water in the cistern to more than 20°C.

Expansion vessels used on unvented hot water systems should preferably be of the ‘flow through type’ and should comply with the requirements of BS 6144 and BS 6920 (all parts).

5.4 Types of hot water generators

5.4.1 Instantaneous gas or electric

Electric wiring shall be in accordance with National Wiring Rules

Gas supply shall be in accordance with IS EN 1775

Flueing and ventilation shall be in accordance with I.S. 813

When a gas-fired instantaneous water heater is used in rooms, a room-sealed type should be selected. The rate of flow of hot water, the temperature rise from feed to delivery, the power consumption and the efficiency of the appliance are related by the formula:

FT=14.3EP

Where:

F is the flow rate (in litres per minute);

T is the temperature rise (in kelvin);

E is the efficiency (ratio of power output to power input);

P is the power input rating (in kilowatts).

If the appliance efficiency is not known, a value of 0,75 may be assumed for gas-fired instantaneous water heaters and 0,90 for electric instantaneous water heaters. This will give a conservative estimate of the flow available for a given temperature rise. Single outlet instantaneous water heaters can be inlet controlled or outlet controlled. Multi-outlet heaters are outlet controlled only and are most satisfactory when only one outlet is used at any one time. For economy in use of fuel and water the heater should be located as close as possible to the hot water outlet in most frequent use, usually the kitchen tap. When close control of temperature is required, e.g. for a shower, thermostatic safety control and/or the use of a heater fitted with a water governor is recommended.

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Alternatively, the heater should be fed from a storage cistern through its own separate feed pipe; most instantaneous shower units require a minimum supply pressure of about 105kPa (1bar) or 10 m head. For information on shower installations, reference should be made to BS 6340-4.

5.4.2 Electric storage water heaters

No hose or other connection shall be made to the outlet of a non-pressure or inlet-controlled storage-type water heater and the outlet shall not be controlled by a valve or tap. Special taps and mixer taps in which the tap mechanism controls water inlet to the heater while the hot water from the heater is discharged through the tap outlet can be used when specified by the heater manufacturer, provided the tap outlet remains unobstructed.

Pressure or outlet controlled type heaters shall be suitable for the supply pressure and there shall be appropriate arrangements to accommodate expansion of the heated water. Many pressure-type water heaters are designed to be supplied from a storage cistern only and will not withstand mains water pressures. For installations in small dwellings a capacity of 100 l to 150 l is sufficient to provide a hot water supply including a supply to a bath. Heaters designed to take advantage of off-peak electricity tariffs may have a capacity of 200 l or more.

For a storage vessel with an electric immersion heater, the storage vessel shall conform to the relevant requirements for preservation of water quality and shall be corrosion resistant. The immersion heater or heaters shall conform to I.S. EN 60335-2-21; all electrical controls shall conform to the relevant clauses of I.S. EN 60730-2. The immersion heater shall be provided with a non-self-resetting thermal energy cut-out device in addition to the normal automatic thermostat. Immersion heaters and controls shall be so located that insertion, removal and adjustment can easily be performed.

5.4.3 Direct and indirect systems

The manufacturer’s recommendations shall be followed to ensure that all heat generated is dissipated when a solid fuel boiler is in slumbering mode. Neither this heat emitter nor its circuit shall be fitted with valves.

Boiler heated hot water systems specified in this code of practise comprise a hot water storage vessel and an independent heating appliance, a back-boiler associated with an open fire or room heater, a boiler incorporated in a cooker, or a gas-fired circulator.

Direct systems shall be designed to achieve gravity circulation between boiler and storage vessel. In hard water areas where scale deposition can obstruct pipes, an indirect system shall be used. A hard water test should be carried out.

‘Hardness’ is the term which describes the concentration of calcium and magnesium salts dissolved in water, usually expressed as calcium carbonate (CaCO3) equivalence. Waters may be classified as given in the Table below.

Table 2 — Classification of water

Designation Total hardness (as CaCO3) Soft 0 - 50 Moderately soft 50 - 100 Slightly hard 100 - 150 Moderately hard 150 - 200 Hard 200 - 300 Very hard > 300

An indirect system shall be used when domestic hot water and hot water central heating are supplied by the same boiler. The primary circuit of an indirect system shall either be cistern fed and vented, or be filled and sealed.

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Many local authorities in the ROI require that the water supply to heating systems is supplied from water storage or other independent source; direct connections to the supply pipe are not allowed. Installers should check with the local authority before progressing with a connection method that may be contrary to local authority byelaws.

No primary or closed circuit shall be connected directly or indirectly to a feed pipe supplied from domestic cold-water storage unless it is fitted with an approved backflow prevention arrangement. In domestic or non domestic installations under 40kw total heat input, where the fluid in the closed circuit is of a risk hazard less than fluid category 3, a temporary connection via an isolating valve and a Type EC or ED double check valve assembly, permanently installed on the water supply installation is permissible for filling or flushing the primary circuit.

Any connection of the above kind shall be made only for such time as is necessary to perform the task in question.

When gravity circulation is required the storage vessel shall be located at a sufficient height above the boiler. Flow and return pipes shall have a route and bore appropriate to the duty required and the circulating pressure available.

This code of practice includes direct and indirect, vented and unvented system.

5.4.3.1 Vented primary circuits

Vented primary circuits shall have a vent route connecting the flow connection on the boiler to the vent pipe outlet above the expansion cistern and a feed water route from a point near the bottom of the feed and expansion cistern to the return connection on the boiler. Except as specified in this section, these routes shall be independent. It is permissible for both these routes to be incorporated in parts of the primary flow and return pipe-work, but the vent route shall not include any valve, pump or any impediment to flow whatsoever.

Vent pipes from primary hot water circuits should be of adequate size, but not less than 19 mm internal diameter. The vent pipe shall have a rise in every part of its course and may terminate through the cover of the cold water feed and expansion cistern and over its respective overflow pipe, providing there is a physical air gap at least equivalent to the size of the vent pipe. No valve shall be fitted in the feed and expansion pipe. Where the vent pipe is not connected to the highest point in the primary circuit, an air release valve shall be installed at that point. The open vent shall rise continuously to its outlet terminating above the feed & expansion cistern to a minimum height of 16

1 of the static head of the system.

A cold water feed and expansion pipe of minimum internal diameter 13 mm shall be taken from the feed and expansion cistern to the system and shall not supply water for any other purpose.

A feed and expansion cistern for a double feed primary circuit shall accommodate 4% expansion of the volume of the water in the circuit. The cold feed and expansion pipe shall not include any impediment to the expansion of the water in the pipe.

Pipes should be installed to avoid air locks and be laid to falls to facilitate draining.

When an installation is designed for combined central and domestic water heating and the central heating circuit includes a circulating pump, while the parallel circuit to the primary heater in the hot water storage vessel operates by gravity circulation, the return pipes of the two circuits should be connected to separate connections on the boiler, or should be combined by means of an injector type fitting installed near the boiler, unless the manufacturers’ instructions specify otherwise.

5.4.3.2 Sealed primary circuits

Pipes sizes in sealed primary circuits shall conform to the relevant requirements for vented primary circuits. In place of the expansion cistern and vent pipe, a sealed primary circuit shall be fitted with an expansion vessel of sufficient capacity to accommodate, with the pressure differentials involved, the increase in volume of the

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water content of the whole of the primary system, including any space heating circuits when heated from 10°C to 110°C.

Indirect cylinders fitted in sealed primary circuits shall have primary heaters suitable for operating at a pressure of 35 kPa (0,35 bar) in excess of the pressure relief valve setting. The specific requirements concerning the safety of sealed primary circuits given in clause 5.4 & 5.6 of BS 6700:2006 shall be conformed to in every case.

5.4.3.3 Double feed and single feed primary circuits

The primary circuit shall either be fed independently of the secondary system, e.g. double feed primary circuit, or be supplied from the secondary system by using a hot water cylinder incorporating a special primary heat exchanger, i.e. single feed primary circuit. A single feed indirect cylinder shall only be used when both primary and secondary systems are of the vented type. Where a single feed indirect cylinder is used:

the cylinder shall conform to BS 1566-2 and shall be installed in accordance with the cylinder and appliance manufacturers’ instructions;

and where the primary circuit is pumped, the static head of the system shall be in excess of the maximum pump head;

no corrosion inhibitor or additive shall be introduced into the primary circuit;

the recommendations of the manufacturers of the boiler and the radiators as to the suitability of their products for use in this system shall be followed.

5.4.3.4 Solar interconnecting of solar to the heating and hot water system

Refer to the CIBSE 'Solar Heating, Design and Installation Guide'.

5.4.3.5 Water heating by solar energy and ground source heat pumps

Solar water heating shall be in accordance with I.S. EN 12976-1 or DD ENV 12977-1. Reference should also be drawn to the CIBSE 'Solar Heating, Design and Installation Guide'.

Ground source heat pumps shall be in accordance with I.S. EN 378-1.

Solar energy may be used to augment a conventional domestic water heating system of the boiler or immersion heater type.

5.5 Stratification and re-circulation of hot water

Stratification within a hot water storage vessel refers to the layers of water at different temperatures throughout the vessel. Hotter water is located at the top of the vessel and the temperature decreases towards the bottom. For this reason tall cylindrical vessels are preferred, fitted with a horizontal cold feed connection located near the base of the vessel. The horizontal connection directs the incoming water across the base of the vessel thus preventing the cold water from lowering the temperature at the top of the vessel.

Where a horizontal vessel is to be installed, the cold feed connection shall be located on the underside of the vessel and fitted with an internal spreader tee to avoid disturbing the layers of hot water within the vessel. The secondary flow connection shall be taken from the opposite side (top).

Re-circulation of hot water (Parasitic circulation) may occur if the open vent (secondary flow) pipe rises directly from the hot water storage vessel towards the cold water storage cistern. One pipe circulation (parasitic circulation) is likely to occur causing substantial heat loss and subsequent excessive energy costs.

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To prevent parasitic circulation the hot water secondary flow pipe shall run for a minimum of 450 mm horizontally from the top of the storage vessel before deviating to the vertical position.

5.6 Health and Safety Considerations

5.6.1 Thermostatic/anti-scald devices

Pressure relief valves, temperature relief valves and combined temperature and pressure relief valves, check valves, pressure reducing valves, anti-vacuum valves and pipe interrupters shall be fitted in accordance with sections 5.3.5 and 8.2.1.4. and shall conform to the relevant standards from: BS 6280, BS 6282 (all parts), BS 6283 (Parts 2 & 4), I.S. EN 1490, I.S. EN 1491, I.S. EN 13076, I.S. EN 13077, I.S. EN 14451 and I.S. EN 14623.

5.6.2 Vented system:

Where the energy source is solid fuel, a temperature relief valve complying with I.S. EN 1490 or a combined temperature & pressure relief valve complying with I.S. EN 1490 shall be provided (fitted at the top of the hot water cylinder). This shall be complete with a readily visible air-break to drain the device and a discharge pipe as described in section 4.6.4.1, except where water in a vented system is heated by a boiler fired by solid fuel as specified in clause 5.b of I.S. EN 12828:2003. The energy supply to each heater or store shall be under thermostatic control.

NOTE I.S. EN 12828:2003 and, where applicable, BS 5546 both require feed cisterns in new or replacement installations to withstand a temperature of 100 °C See both of these standards for further details.

A means of dissipating the power input under temperature fault conditions shall be provided in the form of an adequate vent (not less than 19 mm internal diameter) to atmosphere.

All solid fuel appliances shall have open vents. Pressure and Temperature relief valves must not be used with solid fuel systems under any circumstances as failure of a valve could result in an explosion which could in the most tragic circumstances cause injury or death as solid fuel appliances tend to be situated in kitchen.

5.6.3 Bursting and explosion

Water heaters shall have temperature control and safety devices that ensure that the water temperature does not exceed 100 °C and all fittings and pipework used in the water system shall be protected from bursting.

Electric instantaneous water heaters shall conform to I.S. EN 60335-2-35 and electric storage heaters shall conform to I.S. EN 60335-2-21.

The production of steam in a closed vessel, or the heating of water under pressure to a temperature in excess of 100 °C can be extremely dangerous. A proportion of the water heated in this way flashes into stem when it escapes to atmospheric pressure, with a correspondingly large increase in volume. If such steam escapes in an uncontrolled way, as would result from the rupture of the containing vessel, an explosion will occur. This standard deals only with low temperature systems; consequently a key requirement is that the highest water temperature does not exceed 100 °C at any time at any point in the system. This standard does not deal with systems that are designed to operate with steam or high temperature hot water.

Successful and continuing safe operation of a system is, in practise, dependent upon having the right equipment correctly installed in a well designed system that is properly maintained and not exposed to misguided interference.

The use of appliances that have all the necessary safety devices already fitted to them at the factory is recommended to ensure correct assembly and calibration.

The reliability and durability of the equipment on which the safety of the installation depends should be considered, bearing in mind the conditions under which it will operate.

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On installation, the user should be made aware of the need for regular maintenance.

Equipment susceptible to interference should be protected against this risk. The selection of all equipment, its location and even the choice of system will be influenced by these factors.

5.7 Commissioning and handover

5.7.1 Flushing

Every new water service, cistern, distributing pipe, hot water cylinder or other appliance and any extension or modification to such a service shall be thoroughly flushed with drinking water in accordance with I.S. EN 806-4:2010, Clause 5.2 before being taken into use. Where a system is not brought into use immediately after commissioning and it has not been flushed at regular intervals (up to 30 days depending on the characteristics of the water), it shall be disinfected before bringing into use. Larger diameter pipes may also need to be swabbed to remove debris in addition to simple flushing. This applies particularly to underground pipework.

5.7.2 Disinfection

For single dwellings and minor extensions or alterations in any premises, flushing is all that is normally required, unless contamination is suspected. After flushing, systems shall be disinfected in the following situations;

in new installations (except private dwellings occupied by a single family);

where major extensions or alterations have been carried out;

where underground pipework has been installed (except where localised repairs only have been carried out or junctions have been inserted);

where it is suspected that contamination might have occurred, e.g. fouling by sewage, drainage, animals or physical entry by site personnel for interior inspection, painting or repairs;

where a system has not been in regular use and not regularly flushed;

in situations where disinfection is required, it shall be carried out in accordance with I.S. EN 806-4:2010, Clause 5.3.

5.7.3 Testing

Defects revealed when testing the installation shall be remedied and the tests repeated until a satisfactory result is obtained. Testing shall be done with clean drinking water (particles >= 150um) or, where permitted nationally, by oil free air. Records of all tests undertaken shall be kept by the installer and handed over to the client on completion. The test procedure used depends on the pipework material and it shall be carried out in accordance with I.S. EN 806-4:2010 Clause 5.1.

5.8 Schedule of maintenance

Maintenance procedures shall be adopted to ensure that the performance of the installation is kept at the level specified in BS6700. Unvented hot water storage installations shall only be maintained by a competent person. Responsibility of maintenance normally rests with householder who should note any leaks or discharges from overflows or valves.

The owner of the building shall be provided with maintenance instructions and drawings of the installation particularly showing the location of concealed pipe runs. Any alterations to the system should be recorded and checked for compliance with statutory requirements. The householder shall be shown where the mains stop is and shown how to turn off in the event of a flood. This shall be recorded in the maintenance

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instructions. The householder shall also be given written maintenance instructions and/or shown how to bleed radiators – appropriate tool to be left in log book location

The services of a competent person should be obtained to carry out maintenance and repair. Formality of inspection schedules depends on size, type and complexity of installation. Generally, checks should be performed once a year and they should be in addition to any statutory requirements and to any manufacturer recommended maintenance procedures.

5.8.1 General

Manufacturer’s recommendations and instructions with regard to planned preventative maintenance of meters, pumps, appliances and treatment plant shall be followed. Attention should be paid to prevent water wastage or undue consumption. This applies in particular to self-closing taps, WC's with internal overflow and flushing urinals.

Other than in single dwellings, analysis of water samples wherever drinking water is stored shall be carried out at intervals not exceeding every 6 months. This applies particularly where extensive repairs or alterations have been carried out. Where pipework, fittings or appliances are to be replaced, continuity of earthing and equipotential bonding shall be maintained. Where pipework has been used for earthing, alternative earthing arrangements shall be made in accordance with BS 7430. Where there is no evidence of main equipotential bonding and it may be required, the installer should inform the responsible person that the bonding should be checked and remedied as appropriate.

Other than in single dwellings, checks shall be made on the temperature of water in pipes, cold water cisterns, hot water storage vessels and the discharge from taps to ensure that they are within limits listed in of BS 6700, clause 5.4. These temperature checks should be carried out, during the most adverse conditions, such as at the end of a weekend, during hot weather, full central heating load in the case of cold weather and during high draw-off in cold conditions. Should checks reveal unacceptable temperatures, it will be necessary to install additional insulation, trace heating or carry out modifications or repairs to the systems.

Where there is a risk of legionella colonisation of water services, the system shall be cleaned and disinfected if the system, or part of it, has been substantially altered or opened for maintenance purposes in a manner which could lead to contamination or following an outbreak or suspected outbreak of legionellosis.

5.8.2 Pipework

Provision in fixings and supports for expansion and contraction of pipework shall be checked. Any loose or missing fixings or supports shall be replaced. Leaking joints shall be rectified or where necessary the pipework shall be renewed to stop all leakage. When carrying out renewals, the existing pipework shall be identified and appropriate adaptors and jointing methods used. If inspection of the system reveals leaks or leaks which have been stifled, that component of the system shall be replaced and the offending parts examined by an expert to determine the cause of the leakage. Further action shall be dependent on the results of the examination and recommendations of the examining expert. Pipes showing signs of serious external corrosion should be replaced. The replacement pipe should have suitable protection (e.g. factory plastics coated, spirally wrapped or sleeved with an impervious material) or should be of a corrosion resistant material compatible with the remaining pipework. Any damage to thermal insulation or fire stopping revealed during inspection shall be rectified.

5.8.3 Terminal fittings, valves and meters

Control valves should be clearly labelled and any damaged labels should be restored. Leakage from a float - operated valve (e.g. dripping from a warning pipe) or tap shall be rectified to stop the leakage. Self-closing taps shall be checked at regular intervals to ensure that the period of closing is not excessive. The free movement of infrequently used float-operated valves, particularly those fitted to the feed and expansion cisterns of hot water or space heating systems should be checked at intervals not exceeding one year.

Spray heads on taps and showers should be cleaned periodically and descaled. Gland packings on taps should be tightened or renewed as necessary to prevent any leakage while not impeding the normal operation

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of the fitting. Stop valves should be operated at least once per year to ensure free movement of working parts. Any stiffness or leakage through the gland should be dealt with by lubrication, adjustment or replacement of gland packings or seals. If there is any indication of leakage past the seating of the valve it should be re-washered, re-seated or replaced as necessary. If there is any indication that the waterway of a valve is blocked, the valve should be dismantled, cleared and restored to good working order or replaced. Operation of easing gear might cause the valve to leak.

Meters (other than the water supplier's meters) should be removed at such intervals as experience shows necessary for cleaning and renewal of worn parts, and recalibration. Any indication of malfunction of a pressure control valve should be investigated and remedied. Discharge from an expansion valve or from a cistern warning pipe indicates a possible malfunction of a pressure reducing valve, pressure limiting valve or expansion vessel. Where a pressure gauge is fitted downstream of a pressure control valve, its reading should be checked from time to time and any changes investigated.

5.8.4 Cisterns

Cisterns shall be inspected to ensure that overflow and warning pipes are clear, that covers are not airtight but will exclude light and insects and are securely fixed, and that there are no signs of leakage or deterioration likely to result in leakage. Cisterns storing drinking water shall be inspected annually or more frequently if contamination is suspected. Overflow and warning pipes shall be checked regularly to ensure that they conform to BS 6700, Clause 5.2.4. When found, all debris should be removed from cisterns and cisterns should be emptied, cleaned and disinfected. Where drinking water has been stored in an inadequately protected cistern, a water analysis shall be considered and adequate protection installed.

Metal cisterns showing signs of leakage or corrosion shall preferably be replaced but they can be repaired by internal coating or lining, in accordance with the manufacturer's instructions, with a material conforming to BS 6920 (all parts) as suitable for use in contact with drinking water. In cistern installations, a check shall be made for stagnant water. If stagnant water is found, the cistern(s) shall be flushed and the flow configuration modified so that the flow displaces the whole of the contents continually when the cistern is in routine use. Measures shall be taken to prevent the colonisation of the system with legionella.

5.8.5 Access ducts

All access points should be checked to ensure that they have not been obstructed. Regular inspections should be made to detect any vermin and any necessary measures taken for disinfestations. Crawlways and subways should be inspected at intervals not exceeding six months for leakage from pipework, ingress of ground or surface water and accumulation of flammable materials.

5.8.6 Vessels under pressure

Any vessels storing water under pressure shall be inspected for indications of deterioration in strength and the gas pressure measured no less frequently than at the intervals recommended by the manufacturer. If the gas pressure is not within the limits specified for the application, it shall be adjusted to within those limits. Refer to the EU Pressure Equipment Directive (PED).

5.8.7 Disconnection of used pipework and fittings

If any part of an installation becomes redundant, and in particular if any appliance or fitting is disconnected, other than for the purpose of repair, maintenance or renewal (subject to a maximum of 60 days), then the whole of the pipework supplying water to the disconnected or unused appliance or fitting shall also be disconnected at the source as to leave no legs of unused pipework.

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6 Above Ground Sanitation Systems

When required, a building shall have a drainage system of sufficient capacity to make it capable of the safe and hygienic disposal of foul and surface water from the building. The drainage system must neither allow foul water into a sewer reserved for surface water or surface water into a foul water sewer.

6.1 Types of systems

Most systems in new dwellings are of the Primary Ventilated Stack type (also known as ‘Single Stack’).

The less common Two Pipe System involves the foul water from the WC being kept separate from that from the WHB, bath, sink, shower etc. until they reached the underground drain.

6.1.1 Primary ventilated stack system

This is the standard type of system in dwellings. Figure 4 indicates the minimum pipe sizes, lengths of branch connections and gradients permissible. Generally, this type of system requires appliances to be grouped near the stack.

There are a number of variations on the Single Stack system which, subject to the dwelling being no greater than five storeys, can be installed either internally or externally.

6.1.2 Single stack system variations

Where the performance of the single stack system cannot meet the ventilation demands of the system, separate ventilation will be required. This may be the case on some larger domestic dwellings. This can be accomplished by ventilating each appliance into a separate ventilating stack (Fully Vented One Pipe System) or by providing an auxiliary ventilating pipe connected to the stack itself (Modified Single Stack System).

6.2 Design criteria

6.2.1 Pipework

If the stack serves a WC, it should not be less than 100 mm in diameter. Stacks serving urinals should have a minimum size of 50 mm. While pipe diameter should not reduce in a downstream direction, it is permissible that the dry/ventilating part of the stack to reduce in size to a minimum of 75 mm in one and two storey houses.

For branches serving only one appliance, the diameter of the pipework should be at least the diameter of the trap outlet. If a branch serves more than one appliance and is unventilated, it should confirm to the sizes shown in Table 3.

Bends should be avoided but if they must occur, they should have as large a radius as possible. On branch pipework of less than 65 mm, the bend radius should be a minimum of 75 mm.

T-junctions on branch pipework less than 75 mm should be made with a swept tee of radius 25 mm at least (50 mm if pipework diameter is greater than 75 mm), or at an angle of 45 degrees.

All stacks should discharge into a drain with the bend at the foot of the stack having a minimum radius of 200 mm

Offsets in the wet portions of a stack should be avoided. If the cannot be avoided then no branch should be connected within 750 mm of the offset in buildings up to 3 storeys.

The termination point of the ventilating pipes should be at least 900 mm above any opening into the building within 3 m and it should be covered with an appropriate guard to prevent bird nesting and negative wind effects.

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6.2.2 Branch connections

If the appliances they serve are not on the ground floor of a building, branch pipes should discharge into another branch pipe or directly into the stack.

Unless the branch pipe serves a ground floor wc that is more than 1,5 m above the level of the drain, branch pipes serving only ground floor appliances may also discharge directly into the drain. If a ground floor wc is more than 1,5 m above the level of the drain or any other fixture that is no more 2 metres above, it should discharge as normal into the stack. Alternatively, if the pipe only contains waste water, it is permissible to have it discharging into a gully. If the branch pipe discharges directly into a gully, the pipe should terminate between the grating or sealing plate of the gully and the gully’s water seal.

A branch pipe discharging into a stack must be placed so as to not cause crossflow into an opposing branch. A branch must also not be connected lower than 450 mm above the invert of the drain at the base of the stack up to a level of five storeys. For buildings up to twenty storeys the distance shall be no lower than 750 mm and with no connection on the ground floor.

If the length of a branch exceeds the recommended limits Table 3 then the branch should be ventilated separately to external air, to a ventilating stack (Ventilated System) or a Discharge Stack (Modified Single Stack System).

If a branch pipe is ventilated to external air, the termination point of the branch should be at least 900 mm above any opening into the building within 3 m and it should be covered with an appropriate guard to prevent bird nesting and negative wind effects.

If ventilating a branch back to the main stack, it shall be connected above the spillover level of the highest appliance connected to the stack. This is to prevent any water from the highest appliance draining through the ventilating pipe. The ventilating pipe must also be connected to the branch within 300 mm of the trap. If the ventilating pipe is longer than 15 m or serves more than one appliance, it should be a minimum of 32 mm in diameter; otherwise 25 mm should be sufficient. The ventilating pipe must rise from the appliance to the stack.

6.2.3 Termination

A terminal should be fitted to the top of an external ventilation pipe to prevent birds nesting. In windy areas where the integrity of the trap is at risk from seals being affected by ‘wavering out’, a vent cowl should be fitted.

6.2.4 Access

All stacks and branches should be provided with access points for clearing blockages. These should be placed appropriately to provide convenient access to all lengths of pipework and joints. All pipework should be accessible in the event of repair being required.

If a trap forms an integral part of the appliance, e.g. a wc), the appliance itself should be removable to allow access.

A soil stack should be provided with an access point just above ground level.

6.2.5 Traps and trap seal protection

All discharge points into the drainage system should be fitted with traps to prevent foul air from entering the building.

Trap seal depths for various appliances are shown in Table 4. Traps should maintain a minimum seal of 25 mm under all conditions.

Systems should be designed with adequate ventilation to prevent the trap seal from being compromised.

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6.2.6 Air Admittance Valves

Air-admittance valves provides a convenient means of adding ventilation to a branch by allowing air into a system while preventing foul air from entering a building. They should be placed in non-habitable areas of a building, e.g. attic, where they can be accessed for maintenance and aren’t exposed to freezing conditions. All systems shall include ventilation to atmosphere.

6.2.7 Materials

Materials for joints, fittings and pipes for use in drainage systems are shown in Table 5. The usual precautions should be taken when joining systems of different metals to avoid electrolytic action.

Because drainage systems normally have components exposed to external temperatures, thermal movement should be freely accommodated.

Consideration should be given when fixing system supports for extremes of loading.

Part B of the Second Schedule to the Building Regulations, 1997, and guidance in Technical Guidance Document B relating to penetration of fire separating elements and of fire stopping provisions should be consulted in the relevant situations such as when pipes pass through walls, floors and ceilings.

6.2.8 Connection to under ground systems

Most modern drainage piping systems are made from uPVC, are of a standard size and are easily interconnected. Where piping systems of different materials need to be joined, this is best achieved with a propriety coupling. When joints are being physically fitted together, great care should be taken to ensure the underground pipework is not damaged in the process. This is particularly the case with earthenware and previously damaged cast iron pipework as it can be very fragile. When joints are being filled with sealants, ensure that the bottom of the joint will prevent any filler from falling into the pipework.

6.3 Rainwater

Provision for rainwater drainage is not required for areas of 6m2 or less unless they receive flow from other areas. For information on sizing of systems refer to I.S. EN 12056-3.

Gutters and rainwater pipes are used to collect rainwater to prevent damage to buildings and gardens from water running off the roof.

The collected rainwater is eventually delivered into the drainage system or a soakaway in such a way as to prevent overflow which cold be a hazard in freezing conditions. Gutters should be laid such that any excess of water beyond their designed capacity falls clear from the building. Reclamation of rainwater should be of prime consideration in the design of all new builds and retro-fits.

6.3.1 Sizing

Gutter sizing depends on the area of the surface to be drained and its pitch. Table 6 shows the areas that can be drained by some common gutter sizes. Gutters should fall towards their nearest outlet and at a rate of approximately 1:600.

Rainwater pipes should discharge onto another surface where drainage is subsequently provided or into a gully. If the rainwater is discharged into a drainage system that contains foul water, it should be delivered into the system through a trap.

The diameter of a downpipe should be at least that of the outlet of the gutter it serves. If a downpipe receives water from another it should have a cross sectional at least that of the sum of the outlets it serves.

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6.3.2 Fixing

Gutters should be firmly fixed to the fascia boards or, if these are not present, using rafter brackets.

All fixings used should be of adequate durability and strength with due consideration being given to the potential weight of a ‘full’ system as may occur if the downpipe or gutter gets blocked.

Fixings and joints should not inhibit any thermal movement of the system.

Jointing of systems that are comprised of different metals should be accomplished so as to prevent any electrolytic action.

Rainwater components fitted inside a building should be tested as per normal drainage systems using the same airtightness test.

Supporting brackets should be fitted at branches, shoes, bends and offsets as required. Downpipes should be bracketed every 1,8 m at least.

6.4 Sanitary accommodation & apartments

All dwellings should have at least one wc and one whb. The whb should be located in the same room or in an adjacent room to the one housing the wc.

Except in the case of a building used solely as a dwelling, any food preparation areas should be isolated from the room containing the wc by an adequately ventilated lobby or passageway. In the case of a building used solely as a dwelling, a door between the food preparation area and the room containing the wc is sufficient

6.4.1 Ventilation

For odour control in rooms containing a wc, an external wall vent, appropriate ventilation shall be provided in accordance with the Building Regulations.

6.5 Commissioning and handover

All drainage and internal rainwater systems should be tested for airtightness. I.S. EN 12056-5 details the approach to take. The traps should be filled and then the system sealed at the top of the ventilation pipe(s) and at the entry point to the below ground drainage system. With a positive pressure of 38 mm applied to the closed system, the traps must be capable of maintaining at least a 25 mm seal. Any fall in the test pressure over a 3 minute period should be investigated and repaired. Smoke tests are permissible but care should be taken with systems that include temperature sensitive materials.

Once this test has been passed, all connected appliances should be filled to their overflow levels and the water released. Wc's should be flushed at the same time. When all the water has passed through the drainage system, traps should be checked to ensure they have a minimum seal of 25 mm.

6.6 Maintenance

6.6.1 Blockages

All parts of the system should be provided with adequate access points to clear blockages in pipework and at joints. Traps should be removable or fitted with a cleaning eye to allow access to the pipework adjacent to the appliance. If a trap forms an integral part of the appliance (e.g. a wc) the appliance itself should be removable.

Traps are a major location for blockages in a drainage system due to their shape, the slowing down of the water as it passes and the settling of substances as the water sits in the trap to maintain the seal.

Traps should be cleared using the cleaning eyes provided or, if necessary, by their temporary removal.

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Chemical cleaning agents may be used according to manufacturers instructions with due care being given to the hazards of mixing chemicals inappropriately.

Overflows may be cleared with suitably sized cleaning wires with due care being given over the more delicate nature of some plastic overflows.

If appropriate access points have been provided, most blockages can be cleared without further disassembly of the system. Mechanical means available for smaller bore drainage pipes include plungers and small cleaning springs. For larger bore pipes, drain rods, powered cleaning springs, water jets and other commercial options are available.

6.6.2 Regular Maintenance

Access covers should be regularly checked to ensure they function and a visual inspection of traps, fittings and pipework should be undertaken to look for signs of leakage. Before such an inspection, all appliances should be operated to ensure that traps are filled and there is water available to leak out.

Gutters should be cleaned regularly to remove any debris and silt.

Figure 4 — Minimum pipe sizes, lengths of branch connections and gradients permissible

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Table 3 — Branch pipe limitations

Common branch pipes (unvented)

Appliance Max number to be connected or Max length

of branch (m) Min size of pipe (mm)

Gradient limits (fall per metre)

min (mm) max (mm)

wc's 8 15 100 9 to 90

urinal bowls 5 * 50 18 to 90

urinal stalls 6 * 65 18 to 90

washbasins 4 4

(no bends) 50 18 to 45

NOTE * No limitations as regards venting but should be as short as possible

Table 4 — Trap seal depths for various appliances

Minimum trap sizes and seal depths

Appliance Diameter of trap (mm) Depth of Seal (mm)

washbasin 32 75

bidet 32 75

sink* 40 75

bath* 40 75

shower* 40 75

food waste disposal unit 40 75

urinal bowl 40 75

wc pan 100 minimum 50

* where these appliances are installed on a ground floor and discharged to a gully, the depth of the seal may be reduced to not less than 40 mm

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Table 5 — Materials for joints, fittings and pipes for use in drainage systems

Materials for sanitary pipework

Material Irish/British Standards

Pipes

cast iron BS 416 BS 6087

copper I.S. EN 1057, I.S. EN 1254-1, I.S. EN 1254-2

galvanised steel BS 3868

PVC-u BS 4514, I.S. EN 1329-1

polypropylene I.S. EN 1451-1

Plastics: ABS MUPVC

BS 5255, BS 5556, BS 2782-11.1121B, BS ISO 11922-1, I.S. EN 1329-1, I.S. EN 1451-1, I.S. EN 1455-1, I.S. EN 1519-1, I.S. EN 1565-1, I.S. EN 1566-1

polyethylene I.S. 134, I.S. 135

Traps

plastics BS 3943, I.S. EN 274 (all parts)

NOTE some of these materials may not be suitable for conveying trade effluent.

Table 6 — Areas drained by common gutter sizes

Gutter and outlet sizes

Max effective roof

area (m2)

Gutter size

(mm dia)

Outlet size

(mm dia)

Flow capacity (litres/sec)

6.0 - - -

18.0 75 50 0.38

37.0 100 63 0.78

53.0 115 63 1.11

65.0 125 75 1.37

103.0 150 89 2.16

NOTE Refers to nominal half round eaves gutters laid level with outlets at one end, sharp edged. Round edged outlets allow smaller downpipe sizes.

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7 Space Heating Systems - System Design

7.1 Overview

There are numerous factors that need to be considered when designing a heating system, as follows;

the lifestyle and age of the people who will use the system;

the buildings construction; and

location and the actual design of the system.

The key purpose of this clause is to highlight specific areas of heating design that have an effect on the system’s operating efficiency and long term running costs.

7.2 Objective

The following objectives should be considered;

install a completely new or retro-fit central heating and domestic hot water system in a dwelling;

make the best use of a variety of heat sources and technologies,

maximise energy efficiency while minimizing the environmental impacts including running costs.

While ensuring that occupants can achieve adequate levels of thermal comfort, buildings should be designed and constructed in accordance with the Building Regulations, Irish Standards, the EU Energy Performance of Buildings Directive (EPBD) and the Building Energy Rating scheme (BER). BER is the Republic of Ireland’s government’s standards for home energy rating. Other factors that need to be considered are the Dwelling Energy Assessment Procedure (DEAP) published by Sustainable Energy Ireland (SEI). As part of the Directive, a Building Energy Rating (BER) certificate, which is effectively an energy label, will be required at the point of sale or rental of a building, or on completion of a new building.

A good heating system design can influence the BER rating by the best choice of a high efficiency boiler, the specifications of good system controls and the choice of fuel. Heating systems should be installed with a boiler interlock.

In a system with a combi boiler this can be achieved by fitting a room thermostat. In a system with a regular boiler it can be achieved by the correct wiring interconnection of the room thermostat, cylinder thermostat, and motorised valve(s). It may also be achieved by more advanced controls, such as a boiler energy manager. TRV’s alone are not sufficient for boiler interlock.

7.3 Boiler Efficiency

All oil and gas fired boilers installed in new dwellings and as replacements in existing dwellings shall meet a minimum seasonal net efficiency of 86%.

Refer to the Dept. of Environment, Heritage & Local Government’s Building Regulations TGD Part L and the Heating & Domestic Hot Water for Dwellings – Achieving Compliance with Part L available on the Department's website.

The efficiency of the boiler is dependent on two factors; the design of the boiler and the condition in which it operates.

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Boiler design features;

the heat exchanger’s surface area,

the water capacity of the heat exchanger,

type of ignition system (electronic or pilot flame),

type of burner control,

is the boiler designed to operate in condensing mode?, and,

length and shape of flue.

Conditions affecting the boiler efficiency;

boiler size in relation to the heat emitters and the design load,

the controls on the heating system, and,

temperatures on the flow and return.

To ensure that the efficiency is maintained regular maintenance and servicing are required, especially for oil fired boilers.

7.4 HARP

The Home-heating Appliance Register of Performance (HARP) database is a product efficiency database for home-heating appliances.

HARP is the measure of the average annual efficiency of a domestic boiler. It is applied to most domestic oil and gas boilers and takes into consideration the general pattern of usage, system control and climate. It is calculated from results of standard laboratory tests conducted to the relevant European standards.

HARP efficiency bands have been assigned to boilers on a scale from ‘A’ to ‘G’, as below in Table 7.

Table 7 — HARP range

HARP Range

90% and above

86% - 90%

82% - 86%

78% - 82%

74% 78%

70%-74%

below 70%

7.5 Central heating design

This Code of Practice has been written to encourage designers and installers to ensure that central heating systems are not only designed and installed correctly, but are also energy efficient and meet manufacturer’s

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criteria. The Code of Practice will provide practical information and guidance on wet central heating systems in permanent domestic dwellings, flats, small offices and similar buildings. For further details refer to I.S. EN 12828.

A central heating system should be able to match the heat loss from the dwelling at the design conditions, with an allowance for intermittent operation and hot water usage. Internal design temperatures should be chosen to ensure satisfactory comfort conditions.

When designing the heat loss from a dwelling there are two calculations to consider;

heat that is lost through the structure of the building; walls, roof, windows, doors and floors – this is call the ‘fabric heat loss’.

heat that is loss by the air changes in the dwelling – this is known as ‘the ventilation rate’.

7.6 Fabric Heat loss

Fabric heat losses are losses directly through the walls, windows, doors, floors and ceiling of the room. For ease of calculation, it is assumed that these losses are at a uniform rate through each surface. The heat loss rates are obtained by multiplying the area of each individual surface by the design temperature difference and the heat transfer co-efficient called the 'U' Value. For further details reference should be drawn from I.S. EN ISO 13789.

The 'U Value' of a building fabric is the thermal conductivity of a material (rate of loss of heat in watts) that will flow through one square metre of the material when there is a temperature difference of one degree Kelvin (K). To calculate the heat loss through the whole wall for each degree difference, multiply; the ‘U’ value by the wall area and then by the temperature difference between the inside and outside of the wall.

Design heat loss through wall =

Surface area (m2) x 'U' Value (w/m2/oK) .x Temperature difference (∆T)

Fabric Heat Loss (Watts ) = Area (m2 ) X ‘U’ Value ( w/m2 0C) X ∆T (oC)

The ‘U’ value of a material can be found from the manufacture or from tables such as those TGD Part L Appendix B. Methods can also be found in I.S. EN ISO 6946 and also in the CIBSE guide.

7.7 Ventilation Rate

The difference between the inside and outside temperatures and the rate at which the air enters and leaves the building will affect the ventilation heat loss. The ventilation heat loss rate of a room or building is calculated by the following formula;

Rate of Heat Loss = V * N * ∆T * 0.33

Where;

V = the volume of air in the room (m3),

N = number of air changes per hour,

∆T = Temperature difference between the outside and the inside, and,

0.33 = is a constant factor. It represents the specific heat and density of air.

The principal design considerations are;

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The required internal temperatures of each room,

The design outside temperature (Range -1OC to -3OC), and,

The Ventilation rate of the room(s).

The calculations should include provisions to ensure that the heating up time of the entire system is not excessive. The general principle is to calculate the heat loss rate and the correct radiator sizes, for each room in turn. Then total all heat losses to obtain a total figure. Then add on a factor for the domestic hot water use and thus obtain the correct heating boiler output required.

For further details reference should be drawn from I.S. EN ISO 13789.

7.8 Thermal comfort

Apart from the provision of domestic hot water, the main reason that someone has central heating installed is to ensure that they and their family are provided with warmth at a level at which they can remain comfortable. This "thermal comfort" is a measure of a person's satisfaction with his/her surrounding or thermal environment.

Thermal comfort is achieved when a desirable heat balance, between the body and surroundings are met. These conditions are;

air temperature at feet level, not greater than 30C below that at head level,

airflow past the body is horizontal and at a velocity of between 0.2 m and 0.25 m per second. A variable air velocity is preferable to a constant one,

room surface temperatures not above the air temperatures,

relative humidity of between 40% to 60%, and

air temperatures between 160-220C, dependant upon the type of activity being carried out, age of occupants and the level and quality of clothing.

All these factors are recognized as having an effect on thermal comfort and it is possible to implement a degree of control on all of them to maintain comfort levels. However, the customer aims to achieve this at the lowest possible cost during those periods when heat (thermal comfort) is required.

The introduction of adequate controls is a very important factor in this, but equally is a well-designed and efficient central heating system.

7.8.1 Building exposure

When a building is located in a position where it can be subjected to severe weather conditions such as on the top of a hill, by a riverside, at the coast, or in any extreme open location, allowance should be made for an increased heat input. Other factors include;

temperature extremes;

site location;

humidity conditions;

level of exposure;

wind chill factors,

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frequency & duration

Under these conditions a general rule is to add 10% to the heat losses, but this should be based on local conditions and increased even more if the location is particularly severe.

7.9 Design Temperatures

In practice the temperatures required depend on the client’s preferences and the individual buildings. The actual temperatures achieved will largely depend on the provision of suitable means of control. It is therefore recommended that a design temperature of 22°C be used for bathrooms and 21°C for all other rooms. Using a single design temperature avoids the complexity of calculating heat transfers between rooms and only the heat losses through the external surfaces are considered.

The temperature requirements of the client should be taken into account but the advantages of designing a system to reach the higher temperatures should be explained and how proper controls may be adjusted to provide the required lower temperatures when desired.

7.9.1 External design temperatures

The external design temperature should allow for all but the most extreme conditions and a figure of -1°C is usually chosen.

An external design temperature of -3°C should be used when calculating heat losses on a room by room basis.

With Global Warming the temperature variations in Ireland in recent times have proved these minimum specifications as adequate. A suggested fundamental pre-requisite to system design is the selection of local weather condition information, since absolute maxima or minima are unsuitable, as they may lead to uneconomic design temperatures.

7.9.2 Internal design temperatures and ventilation rates

The following internal design temperatures and air change rates are recommended for the design of full and part central heating systems and are based on providing the customer with acceptable comfort levels throughout. The minimum design temperature and air change rates required are set out in Table 8 below.

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Table 8 — Internal design temperatures and ventilation rates

Room Temp °C Air Changes per hour Lounge sitting room

21 1,5 Living room 21 1,5 Dining room 21 1,5 Kitchen 18 2,0 Breakfast room 21 2,0 Kitchen/Breakfast 21 2,0 Hall 18 2,0 Cloakroom 18 2,0 Toilet 18 2,0 Utility Room 18 1,5 Study 21 1,5 Games Room 21 1,5 Bedroom 18 1,0 Bedroom/en suite 18 2,0 Bedsitting 21 1,5 Bedroom/Study 21 1,5 Landing 18 2,0 Bathroom 22 2,0 Dressing room 21 1,5 Storeroom 16 1,0

7.9.3 Calculating heat loss from a room

Before we can consider selecting radiators or heat emitters for a particular area it is necessary to be able to calculate the heat loss from that area. A radiator can then be selected to provides an appropriate output, (under a set of predetermined conditions), to match the heat loss from the area under the same conditions. This process can then be repeated for other areas eventually leading to a heat loss calculation for the whole building. With the addition of an allowance for domestic hot water and possible intermittent usage, a suitably sized boiler can then be selected. In order to establish the total radiator output and hence size required we need to consider the following: -

Consider a simple heat loss calculation for a typical bedroom shown in Figure 5 below.

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NOTE 1 Temperature of room above – 1 OC (Roof) NOTE 2 Temperature of room below + 23 OC

Sample ‘U’ values;

External wall 0,92 W/m2/k- Temperature differential

Internal wall 1,7 W/m2/k- Temperature differential

Window 5 W/m2/k- Temperature differential

Party wall 2,1 W/m2/k- Temperature differential

Ceiling 0,34 W/m2/k- Temperature differential

Floor 1,36 W/m2/k- Temperature differential

Figure 5 — Heat loss calculation for a bedroom

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The total room heat loss from the room / area is given by:

Total Room Heat Loss = Fabric Heat Loss + Ventilation Heat Loss

Heat loss calculation for the bedroom example;Surface Element Area X ‘U’ Value X Temp/Diff = Heat loss Heat Gain

( m2 ) X (W/m2 / OC) X (OC ) = Watts

External wall 5.5 x 0.92 x 19 96.14

Window 2.0 x 5 x 19 190

Party Wall 10 x 2.1 x 8 168

Internal wall 1 7.5 x 1.7 x 0 0

Ceiling 12 x 0.34 x 19 77.52

Floor 12 x 1.36 x -5 -81.6

Internal wall 2 10 x 1.7 x -2 -34

Totals 531.66 115.6

Total Heat Loss Less Heat Gain = 416.06

Ventilation Heat loss

Room Volume X Air Changes X Temp Diff X Vent Factor = Heat loss

( m3 ) x Air Changes x (OC ) x 0.33 = Watts

30 x 2 x 19 x 0.33 = 376

Total Heat loss = Fabric Heat Loss + Ventilation Heat Loss

416.06 + 376.2 792.26 W

Note:

1. The Floor and the Internal Wall 2 have a heat gain into the bedroom due to higher temperatures in the Adjacent Room and the Room below. 2. All "U" values are taken from British Standards 3. Correction factors need to be added to the calculated

Before a radiator can be selected the calculated heat loss figure needs to be adjusted to compensate for the difference between the tested radiator outputs advertised in the brochures and the actual output obtained from the radiator after considering the design criteria of the system.

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7.10 Requirements for ventilation

In order to restrict the build up of moisture, odours and pollutants ventilation is needed to provide fresh air to living spaces. Ventilation requirements are set by the Building Regulations and are usually achieved by the installation of extractor fans in the kitchen/bathrooms, by windows and by trickle ventilators in other rooms. When considering heat loss through ventilation it is preferable to minimise ventilation but this should not be done to the extent that it harms the air quality and the heating designer should provide a system that can cope with the total expected heat load.

Guidance on how to provide adequate ventilation in dwellings is given in the Building Regulations, which aims to achieve both rapid extraction of moisture from kitchens and bathrooms and to provide background ventilation in other rooms, which otherwise would be a hazard to health. Table 9 summarises the typical requirements but reference must be made to the current buildings applying where the dwelling is located.

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Table 9 — Basic ventilation provision using background ventilators and specific provision for extract and purge ventilation

Room or Space General ventilation Extract ventilation Purge ventilation

Minimum equivalent area of background ventilatora (mm2)

Extract fanb - Minimum intermittent extract rate (L/s)

Opening window or external door - Minimum provision

Habitable Room 5000c, d - 1/20 of room floor area

Kitchen 2500c, d, e 60l/s generally

30l/s if immediately adjacent to cooker (e.g. cooker hood-not recirculating)

Window opening clause (no size requirement)e

Utility Room 2500c, d, e 30 l/s Window opening clause (no size requirement)e

Bathroom 2500c, d, e 15 l/s Window opening clause (no size requirement)e

Sanitary Accommodation (no bath or shower)

2500c, d, e 6 l/sf Window opening clause (no size requirement)e

NOTE 1 Equivalent Area is the area of sharp-edged orifice through which air would pass at the same volume flow rate, as the opening when the applied pressure difference is identical. Equivalent area is measured in accordance with the method specified in I.S. EN 13141-1. Information on equivalent area of ventilation products, e.g. trickle ventilators, should be supplied by the product manufacturer. Where this information is not available, the free area may be used to assess compliance but the area of ventilator required should be increased by 25%.

NOTE 2 Refer to Building Regulations Technical Guidance Document F for passive ventilators or continuous room ventilators with heat recovery.

NOTE 3 The equivalent area of background ventilator should be increased by 50% where an infiltration rate of less than 7m3/m2h at pressure difference of 50Pa is measured or assumed for the purposes of calculating energy use and CO2 emissions using the DEAP methodology.

NOTE 4 Refer to Building Regulations Technical Guidance Document F for the extent and location of background ventilation where there is only a single exposed façade and cross-ventilation is not possible.

NOTE 5 Refer to Building Regulations Technical Guidance Document F for ventilation provision where the provision of background ventilation and purge ventilation is not possible, e.g. when there is no external wall.

NOTE 6 As an alternative, the opening window clause provided for purge ventilation may also be relied on for extract ventilation.

NOTE 7 Refer to Building Regulations Technical Guidance Document F for provision of ventilation of habitable rooms through other rooms or into courtyards.

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7.10.1 Ventilation Heat loss

Ventilation air, flowing through the building loses heat. Ventilation rates are usually quoted as 'air changes per hour' defined as the volume of ventilation air moving through the room per hour, divided by the volume of the room itself. The air will be heated by the heating system and the heat needed is calculated by multiplying the room volume, by the air change rate, by the temperature rise the air needs, and by the ventilation factor.

Thus the rate of loss of heat through ventilation loss is given by;

Ventilation Heat Loss

Room Volume x Air Change Rate x Temperature Difference x Ventilation Factor

( Watts ) m3 x Qty x OC x 0,33

7.10.2 Ventilation rates

The ventilation factor is taken as the specific heat of air at 20OC which is 0,33 W / m3 / 0C and is used to calculate the heat loss to the air changing within the rooms due to infiltration or mechanical ventilation.

The air change rates in Table 10 are for modern buildings. When designing for older properties, consideration should be given to increasing the air change rates to allow for ill fitting doors, windows etc

Room TempoC Air changes per hour

Room TempoC Air changes per hour Lounge sitting room 21 1.5 Study 21 1.5

Living room 21 1.5 Games Room 21 1.5

Dining room 21 1.5 Bedroom 18 1.0

Kitchen 18 2.0 Bedroom/en suite

18 2.0

Breakfast room 21 2.0 Bedsitting 21 1.5

Kitchen/Breakfast 21 2.0 Bedroom/Study 21 1.5

Hall 18 2.0 Landing 18 2.0

Cloakroom 18 2.0 Bathroom 22 2.0

Toilet 18 2.0 Dressing room 21 1.5

Utility Room 18 1.5 Storeroom 16 1.0

Table 10 — Air change rates for modern buildings

7.10.3 Mechanical extraction ventilation

Where mechanical extraction ventilation is installed in a room it is possible for the minimum fan duty to exceed the minimum air change rate. In such cases it is advisable to allow for the increased air change in the heat loss calculation for both the room and the connecting rooms from which the air will be drawn.

Where a shower or bath is fitted into a bedroom or where an opening without doors exists between the bedroom and the en-suite facility, then the air change rate of the bedroom should be increased accordingly to allow for the movement of air caused by the extract fan.

In addition, extractor fans may interfere with the operation of the appliance causing negative pressure and should be correctly accounted for to avoid smoke spill out.

Where both open flued combustion appliances (including open fires) and extract fans are installed in the same dwelling, it should be verified that the combustion appliance can operate effectively and safely whether or not the fans are running. A reduced rate of extraction may be appropriate in these circumstances.

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Reference should be made to BRE Information Paper 1P 7/94 Spillage of flue gases from solid-fuel combustion appliances and BRE Information Paper IP 21/92, Spillage of flue gases from open-flued combustion appliances. See also additional guidance in Technical Guidance Document J.

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8 System Selection

8.1 Fuel selection and type

It is important that there is a clear understanding between the installer and the client as to the client’s requirements and preferences. This is necessary to ensure that a suitable system is designed and specified. Many factors need to be accounted for at this stage, including choice of fuel, type and location of the heat supply (boiler etc) and the suitability of the new system for integrating with any existing system.

The choice of fuel is important particularly because of its effect on running costs. In addition, the choice of fuel may be constrained due to unavailability (e.g. mains gas in rural areas), fuel storage (e.g. volume requirements for bulky solid fuels) or delivery access (tanker delivered fuels e.g. bulk pellets, oil or LPG).

Attention shall be taken of any regulations or standards that pertain to the selected fuel. Examples of this would be I.S. 813 (Domestic Gas Installations), BS 5410-1 (Oil firing installations) and the Building Regulations Parts F, J & L.

8.2 Renewable Energy systems:

Installation of a renewable energy heating system involves a major investment on behalf of the client. Generally these are new technology areas and it is important that the client is fully informed and is provided with a system that meets their requirements and expectations. The provision of 10 kWh/m2/annum contributing to energy use for domestic hot water heating, space heating or cooling or equivalent represents a reasonable minimum level of energy provision from renewable energy technologies in order to satisfy Building Regulations.

In Ireland, due to a combination of financial incentives and growing market share, the four most common renewable technologies are;

solar thermal systems,

bio liquids boilers/stoves,

biomass boilers / stoves, and

heatpumps

The efficiency of a particular system is an important factor in choosing an appropriate renewable technology. A complete listing of renewable products and their performance criteria can be found on the Heating Appliances Register of Performance (HARP) on the SEI website (www.sei.ie/harp).

8.2.1 Solar Thermal systems:

8.2.1.1 Selection and type

Solar thermal systems convert solar energy in to hot water, providing free energy for a large proportion of the year. While typically they are designed to meet the domestic hot water requirement of a dwelling, in Ireland, solar collectors alone cannot provide all the hot water for a household’s needs throughout the year. Correctly sized they will supply 60% of heat / domestic hot water needs. They are normally installed in conjunction with a conventional back-up heating system. Detailed information on the installation of solar panels can be found in the second part of this code of practice, SR 50-2.

A typical system comprises of;

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a solar collector (flat plate or evacuated tube) which absorbs solar radiation (sunlight) and changes it into heat;

A pump which transfers the heat from the collector to hot water in a storage tank;

The storage tank accumulates the hot water produced by solar energy so that it can be stored for use when needed;

A number of accessories which ensure the regulation and the safety of the system;

A back-up heater (gas, oil, or wood fuelled boiler, immersion heater or heat pump) which will bring the hot water to the temperature required when there is not enough sunlight to do so (mostly in winter).

8.2.1.2 Location

The optimum location for solar panel collectors for all year round energy collection is roughly south facing and at a tilt angle of 30°- 45° to the horizontal (however angles between 15° and 60° are also acceptable). It is also important that the collectors are positioned so there are no shadows on them during the middle of the day. Shading can be from the collectors themselves, or from trees, chimneys, part of the building or adjacent buildings.

8.2.1.3 Cylinder

An appropriately sized cylinder should be chosen for the dwelling. The volume of the solar hot water cylinder is dependant on the maximum cylinder temperature. It is recommended that for cylinders with a maximum temperature of 60°C that 70 litres per m2 of panel aperture area is supplied. For higher storage temperatures, cylinders with maximum storage temperatures of 80 – 90 °C, 50 litres per square metre of panel aperture area should be sufficient. Smaller capacities will limit the benefit from the system and may lead to frequent overheating of the solar circuit. Where possible, dual-coil cylinders specifically designed for solar should be used. These have the coils at the top and bottom of the cylinder. The solar collector circuit should be connected to the bottom coil and the auxiliary circuit to the top coil, which will enable the solar system to pre-heat in bad weather.

8.2.1.4 Thermal Mixing Valve (Anti-Scald Valve)

Best practice calls for the fitting of a thermal mixing (anti-scald) valve. This applies to all hot water systems and not just solar heated water systems. With the current recommendation to store hot water at 60°C to prevent the growth of legionella bacteria it is becoming more of a consideration to install thermal mixing valves. A thermal mixing valve mixes cold and hot water together to ensure the water temperature is safe for people to use. Refer to sections 5.3.5., 5.6.1 and 8.2.1.4.

8.2.1.5 Controller

After commissioning, a permanent power supply should be provided for the solar controller to ensure circulation in the solar loop.

8.2.2 Biomass heating systems:

8.2.2.1 Selection and type

The most common biomass fuels are logs, wood chips and wood pellets. Modern wood chip or pellet boilers offer an alternative to traditional fossil fuels in providing warmth and comfort heating while being highly efficient, clean burning and totally automatic, saving time and money. However, they can be more expensive than traditional systems, have larger installation footprints and storage requirements and may require additional services such as extra fluing and addition hydronic system linkup.

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Automatic fuel feeding and ignition is an important consideration, Chip or Pellet boilers are lit automatically and continue to operate without manual intervention.

Typically biomass systems will be designed to be the main heating system (space and water) of the dwelling, although it is quite common for them to be installed with a complementary system (e.g. solar thermal collectors, auxiliary oil or gas backup systems). The following sections sets out the main issues to consider when specifying / installing biomass systems.

8.2.2.2 Flues

Typically the flue is installed through an existing chimney or outside the building. The flue shall be installed in accordance with part J of the Building Regulations. Some general guidelines require that the flue should;

be above the eaves line by about 1 m or 600 mm if coming out near the roof apex;

be twin walled and insulated;

have a cowl or hood on top to help prevent down draught;

be separated from any combustible material.

8.2.2.3 Constructional Hearth

A constructional hearth should be placed (see Part J of the Building Regulations) under a stove to separate the stove from combustible material and to provide protection from the threat of fire. The constructional hearth could be a metal or a non-combustible plate. The appliance should not be placed close to the edge of a hearth or any combustible material.

8.2.2.4 Air Supply

A stove or boiler must have a secure air supply for safe operation and installation shall be carried out as per manufacturer’s instructions. This can be either in the form of a controlled dedicated air supply directly to the appliance, or in the form of a permanent ventilation opening to the room in which the appliance is located. In rooms where combustion appliances are used, a lack of combustion air could lead to a build-up of carbon monoxide in the room. Carbon monoxide is a poisonous gas and can have potentially fatal consequences for the occupants of the room.

To prevent carbon monoxide poisoning boilers shall be installed with appropriate air supply, appropriate maintenance shall be carried out, warning signs installed, appropriate air supply in the room and the use of CO detectors should be considered.

Best practise is to rely upon dedicated ventilation and not on air infiltration and/or leakage in the room. The size of the opening depends on the size (in kWh) of the appliance.

The following Guidance for permanent ventilation is given in Building Regulations 1997 Technical Guidance Document J.

8.2.2.4.1 Air supply for solid fuel appliances with a rated output up to 45 kW

Any room or space containing an appliance should have a ventilation opening (or openings) of at least the size shown in table below.

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Table 11 — Air Supply to Appliance

Solid fuel burning open appliance

A ventilation opening (or openings) with a total free area of at least 50% of the appliance throat opening

area (of which at least 6500 mm2 is permanent ventilation) shall be provided.

For description and dimensions of ‚throat’, see BS 8303-1

Other solid fuel appliance A permanent air entry or opening with a total free area of at least 550 mm2 per kW of rated output above 5 kW shall be provided but in no case less than 6500 mm2.

Where a flue draught stabiliser is used the total free area should be increased by 300 mm2 for each kW of

rated output.

8.2.2.4.2 Air Supply for individually flued (non-fan assisted) gas burning appliances with a rated input up to 60 kW and for gas burning cooking appliances (other than for balanced flued or solid fuel effect appliances)

Any room or space containing a cooker should have an openable window or other means of providing ventilation. If the room or space has a volume less than 10m3, then, in addition, a permanent ventilation opening of at least 5000 mm2 should be provided.

Any room or space containing an open-flued appliance should have a permanent ventilation opening of at least 450 mm2 for each kW of appliance input rating, but in no case less than 6500 mm2.

8.2.2.4.3 Air Supply for oil burning appliances with a rated output up to 45 kW

Any room or space containing an appliance (other than a balanced-flued appliance) should have a permanent ventilation opening of free area at least 550 mm2 for each kW of rated output above 5 kW, but in no case less than 6500 mm2. BS 5410-1 requires minimum 100 cm2 (10,000 mm2) for vaporizing appliances.

8.2.2.5 Bulk Fuel Storage

All biomass boiler installations shall require the provision of bulk storage. It shall be required to meet local building and fire regulations. The ONORM M7137 Austrian Standard shall be used as a guideline for DIY bulk storage units. Bulk storage capacity depends on the fuel selected but should be able to store a reasonable proportion of a dwelling’s annual heat requirement.

8.2.2.6 Buffer Heat Store

It is a recommendation that a buffer or accumulator tank be incorporated as part of domestic biomass system installation where applicable, particularly if logs are the primary fuel. A buffer or accumulator cylinder in a domestic biomass heating installation is a primary heat storage/distribution cylinder, which is heated by the boiler to a set temperature and can store the resulting high temperature water for long system standstill periods, until heating or hot water is required. A buffer / accumulator reduces the on/off cycling of wood boilers by “smoothing” the heat output to the dwelling. The buffer or accumulator capacity should be calculated in accordance with manufacturer’s recommendations. A rough guideline for establishing the volume of the buffer is available from I.S. EN 303-5 is in the region of 55 to 65 L/kW of the rated boiler size.

The use of a buffer / accumulator is noteworthy in the following situations;

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where the boiler does not have full modulation capabilities: the use of a buffer will smooth the heat output to the dwelling, and

in situations where the boiler is not capable of supplying the full heat demand of the house, a buffer tank will allow the boiler to run for longer at optimum efficiency extracting maximum potential from the boiler and fuel.

8.2.2.7 Emitter types

Biomass systems are able to supply the most common types of heat emitters including; under-floor heating, radiators and warm air systems.

8.2.2.8 Fuel quality

A high quality of fuel is essential to ensure clean combustion and trouble-free operation of biomass appliances. Clients should be advised as to the availability, and affordability, of quality fuels. Some of the more common quality standards are:

Europe: CEN TS 14961

Austria: ÖNORM M1735

Sweden: SS 187120 and SS 187121

Germany: DIN 51731

8.2.3 Heatpump thermal systems

8.2.3.1 Selection and type

A heat pump system harnesses renewable energy sources to provide heating and hot water to a dwelling.

There are three main types of heat pump available on the market, those that take heat from the ground, from water (rivers or wells) or directly from the air. Ground source heat pumps come in two varieties, vertical bore or horizontal loop.

Heat pumps are very economical when sized correctly, for every unit of electricity used to power the heat pump, 3 to 4 units of heat are generated. They work best in conjunction with low temperature heat distribution systems e.g. underfloor heating. Heatpumps require electricity to run and are therefore most cost effective when they can use night rate electricity which requires a night rate meter. A buffer store is required to maximise efficiency as this allows the heat pump to store heat on a constant basis, releasing it as and when required.

8.2.3.2 Ground source collector

This collector is used in closed loop systems to transfer the heat from the ground to the house. The design and installation of this collector is important to ensure that the system works with maximum efficiency. It is important that the installer provides a plan of the site showing the collector area and depth. This could prevent damage to the collector if any future work or landscaping is carried out on the grounds. In addition photographs of the collector before it is covered up would be helpful with any future work or trouble-shooting of the heat pump system.

8.2.3.3 Air - source heat pump

Air heat pumps take the energy from the air and transfer it to a warm air heating system and air/water heat pumps take the energy from the air and transfer it to the water in a heating system.

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8.2.3.4 Water - source heat pump

Water source heat pumps work in a similar fashion to ground source systems and transfer the heat from a water source to the dwelling. Water source heat pumps use an open loop collector.

Due to the complexity of a typical system, it is recommended that the installer creates a piping schematic, valve chart and wiring diagrams.

8.2.3.5 Emitter types

Although warm air systems and low temperature radiators can be used in conjunction with heat pump systems, the most common emitter will be an under floor heating system. It is important that the installer discusses the requirements and suitability of an under floor heating system with the client. In particular it is important to identify the level of floor insulation involved and to identify floor covering types likely to be used, as these affect the heat transfer from the floor and the overall operation of the system.

8.3 Domestic Heating Oil Storage Tanks

8.3.1 Introduction

The following guidance relates only to oil used solely to serve a fixed combustion appliance providing space heating, hot water or cooking facilities in a domestic building. There is other legislation covering the storage of oils for other purposes. Heating oils comprise of Class C2 (kerosene) or Class D (gas oil) to BS 2869. It is recommended that installations follow the guidance contained within BS 5410-1.

8.3.2 Installation

To comply with the requirements of the building regulations you must make sure that oil tanks and oil pipes are constructed, installed and protected to reduce the risk of oil escaping and causing pollution. Before choosing the location of a domestic oil storage tank, to show compliance with the Building Regulations and BS 5410-1 a risk assessment needs to be undertaken to determine whether or not it is permissible to omit secondary containment. It is recommended that a bunded tank be installed unless a risk shows otherwise. The following risk assessment must be carried out and if any of these points apply, the oil tank needs secondary containment;

the oil tank has a capacity of greater than 2500 l,

the oil tank is sited within 10 m of "controlled water" such as a stream, ditch, river, lake, pond, canal or coastal water,

the oil tank is sited where any oil spillage could run into an open drain or loose fitting manhole cover,

the oil tank is sited within 50 m of ground sources potable drinking water, such as a well, borehole or spring,

the oil tank is sited over hard ground or hard surfaced ground that could allow spilled oil to enter "controlled water",

the oil tank is sited where the tank vent pipe outlet cannot be seen from the fill point,

the oil tank is supplying oil to a building other than a single family dwelling, or

any other potential hazard individual to the site.

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8.3.3 Oil Supply

The oil feed installation from the oil storage tank to the appliance should meet the recommendations contained in BS 5410-1, including the fitting of a remote acting fire valve.

8.3.4 Secondary containment

If secondary containment is needed an integrally bunded tank manufactured to an appropriate standard such as OFTEC Standard OFS T100 for plastic tanks or OFS T200 for steel tanks or a suitably designed and constructed bund/catchpit from masonry or concrete built to CIRIA Report 163 should be used. The bund/catchpit should be constructed with a non-combustible material and capable of containing the contents of the tank, plus an additional 10%.

Where an oil storage tank does not exceed 2500 l capacity and its location passes a pollution risk assessment a single skin tank may be considered.

8.3.4.1 Indicative top outlet integrally bunded plastic oil storage tank

NOTE Overfill prevention devices can either be Type A or B to I.S. EN 13616

Figure 6 — Indicative top outlet integrally bunded plastic oil storage tank

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8.3.4.2 Indicative integrally bunded steel oil storage tank

Figure 7 — Indicative integrally bunded steel oil storage tank

A bund is a catchpit beneath the tank, without a drain and capable of containing the contents of the tank, plus an additional 10%.

A chamber is a fully enclosed ventilated space, bounded by non-combustible 60 minutes fire resisting construction (see Technical Guidance Document B and BS 5410-), including a self closing fire door wholly above the bund level.

The chamber should be ventilated directly to the open air so that there is no stagnation. Ventilation should preferably be achieved by natural means, in practice, cross flow ventilation at high level through air bricks is usually sufficient, but there must be no openings into the chamber.

8.3.4.3 Oil storage tank with a capacity over 3500 litres.

The location of an oil storage tank with a capacity which exceeds 3500 l should be in accordance with the requirements of BS 5410-2 as appropriate and any environmental legislation on the control of pollution.

8.3.4.4 Fire protection

An oil storage tank should be located so as to minimise the possible exposure of the tank to the effects of a fire. Protection of the tank is generally achieved by locating the tank so as to achieve a minimum separation distance from the building or by the provision of non-combustible fire resisting barriers or screen walls between the tank and the building.

A barrier means an imperforated fire rated wall or screen at least 300 mm higher and extending 300 mm beyond either end of the tank, constructed so as to prevent the passage of direct radiated heat to the tank; the wall or screen should not have less than 30 minutes fire resistance (see Technical Guidance Document B and BS 5410-1). An external wall of a building may be considered as a barrier or screen wall where it meets the non combustibility and fire resistance requirements. In these situations, particular care should be taken in relation to unprotected openings such as doors and windows and the proximity of combustible building

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elements, such as overhead roof eaves. Guidance on minimum separation distances from buildings and boundaries for oil storage tanks is given in BS 5410-1, together with guidance on protection measures, including the provision of screen walls, where such distances are reduced. BS 5410-1 refers to tanks which comply with specific standards. Where a tank is used which is not covered by the guidance in BS 5410-1, the protective measures should be appropriate to the level of risk of fire spread to the tank. The oil feed installation from the oil storage tank to the appliance should conform to the recommendations contained in BS 5410-1, including the fitting of a remote acting fire valve.

8.3.4.5 Fire rated screen walls for oil storage tanks

For domestic installations not exceeding 3500 l a 30 minutes fire rated construction, prevent the passage of direction radiated heat and extend not less than 300 mm beyond the top and ends of the tanks

For screen wall installations above 3500 litres a 120 minutes fire rated construction should be used and this should extend not less than 900 mm beyond the top and ends of the tank.

NOTE Covers domestic above 3500 litres and all non-domestic tanks (BS 5410-2).

8.3.4.6 Fire protection by separation

Oil tanks should be located at a distance from a building. Building means any structure or erection, whether temporary or permanent, other than a structure or erection consisting of, or ancillary to any:

public road (including any bridge on which the road is carried), private road, sewer or water main,aerodrome runway, railway line, large raised reservoir, wires and cables, their supports above ground and other apparatus used for telephonic or telegraphic communication, orreferences to a building including a prospective building,Reference should be made to BS 5410-1. Further guidance may be

obtained from OFTEC Technical Book 3. Precautions should also be taken when an oil storage tank is located close to a boundary. Boundary means a boundary between land on which the building is situated and land in different occupation so however that: in relation to any road whether public or private, public access way or public right of way, river, stream, canal, lake, pond, common land or a public open space it should be taken to mean the centre line thereof; and the sea and its foreshore should not be regarded as land in different occupation. The installation of a tank should not inhibit full development of a neighbouring plot. Any screening, including plants and foliage used to screen the tank should be kept at least 600 mm away from the tank. An oil tank with a capacity of not more than 3500 litres should be located in accordance with the following table:

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Location of tank

Protection required for buildings without openings

Protection required buildings with openings

Not more than 1.8 m from any

part of any building

Non-combustible base; and any part of the eaves not more than 1.8 m from the tank and extending 300 mm beyond each side of the tank must be non-combustible; and either:

a: any part of a building not more than 1.8 m from the tank should be of non-combustible construction.

or

b: a barrier.

Non-combustible base; and any part of the eaves not more than 1.8 m from the tank and extending 300 mm beyond each side of the tank must be non-combustible; and a barrier between the tank and any part of a building not more than 1.8 m from the tank.

More than 1.8 m from any building

Non-combustible base

Not more than 760 mm from a

boundary

Non-combustible base, and a barrier, or a wall with a non-combustible construction

More than 760 mm from a

boundary

Non-combustible base.

Externally, wholly below ground

No protection required.

Table 12 — Location of tank with capacity not more than 3500 l

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NOTE 1 Non fire rated boundary has less than 30 minutes fire resistance.

NOTE 2 Non-combustible base should cover the area beneath the oil storage tank (and any integral bund) and extend 300mm outside the oil storage tank (and any integral bund) on all sides except where the;

oil storage tank is next to a fire rated wall with a minimum 30 minutes fire resistance;

tank is located over an existing non-combustible surface, which also extends 300 mm outside the oil storage tank.

NOTE 3 Non fire rated wall of a building a has a fire resistance of less than 30 minutes to internal fire.

Figure 8 — Location of tank with capacity not more than 3500 l

An oil tank with a capacity of more than 3500 l should be located in accordance with the recommendations in BS 5410-2.

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Figure 9 — Diagram of oil tank positioning

8.3.4.7 Additional fire protection

The fuel feed system from the storage tank to the combustion appliance is also a potential hazard in the event of fire. The fire valve on the fuel feed, should be fitted in accordance with of BS 5410-1:1997, subclause 8.3 and OFTEC Technical Book 3.

Oil pipelines located inside a building should be run in copper or steel pipe. The recommendations of of BS 5410-1:1997, subclause 8.3 and OFTEC Technical Book 3 should be followed.

Fire can also spread to an oil storage tank over the ground. Provision should therefore be made to prevent the tank becoming overgrown such as a solid, non-combustible base in full contact with the ground. A base of concrete at least 100 mm thick or of paving slabs at least 42 mm thick that extends at least 300 mm beyond all sides of the tank would be appropriate. However, where the tank is not more than 300 mm from a barrier or a wall of non-combustible construction type, the base need only extend as far as the barrier or wall.

8.3.4.8 Fire valve positioning

Fire valves must be of remote sensor resettable type and should be fitted as per BS 5410-1. Fire valves that are located externally where necessary must be protected from the elements, for example with a cover, as per manufacturer’s instructions. Electronic type valves must not be able to automatically reopen after interruption of power when connected to vaporising appliances.

Less Than

1.8 metres

Non fire-rated eaves

Oil Tank

Piers or Raised Base if Required

Non Combustible Base

Fire Protection Cladding

300mm 300mm

Platform

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8.3.4.9 External Boiler

Fire valves are required for externally positioned boilers even though the oil does not enter the building. BS 5410-1 requires the fire valve body to be fitted at least 1 m away from the external appliance case with its sensor located over the burner in the normal manner. De-aerators (such as Tiger Loops) should only be installed externally to buildings and must not be fitted inside boiler casing, including external ‘cabin pack’ type boiler units as per OFTEC technical book 3.

8.3.4.10 Vaporising range cookers

A fire valve sensor is fitted internally to operate a fire valve close to the appliance in a position designated by the manufacturer. This valve is not sufficient on its own to provide the required level of fire protection. An additional fire valve with its sensor positioned just above the oil control valve is required to cut off the oil supply externally before it enters the building.

8.3.4.11 Vaporising room heater (stove)

Oil fired vaporising room heaters require the fitment of a remote sensing fire valve body externally in the oil supply before it enters the building with the valve sensor affixed at the appliance specifically as designated by the appliance manufacturer.

8.3.4.12 Storage within a building

Oil tanks of the integrally bunded type should be used for internal installations, however, where this is not so, the oil storage tank chamber must then form a bund or catchpit that holds at least 110% of the contents of the oil storage tank. The chamber access door will not open below the top of the bund part of the chamber, which means that it is normally formed as a hatch. Masonry or concrete bunds must be built to comply with CIRIA Report 163 (The Construction of Bunds for Oil Storage Tanks).

Where a storage tank is located inside a building, additional safety provisions should be made including the following;

The requirements of BS 5410-1 regarding the protection of oil storage tanks inside a building or structure (including domestic garages) are that the oil storage tank must be fully enclosed in a chamber to prevent fire reaching the tank. The chamber must be of fire resistant construction with a rating of not less than 60 minutes. The chamber must be provided with a self-closing door that opens outwards, and which is readily openable from the inside without the use of a key. Fire resistant purpose-made doors are available.

If both the oil storage tank and the appliance are within the same building area, the oil supply line will very probably also be entirely internal. In this case, the fire safety valve body should be positioned immediately before the oil line leaves the chamber the oil line leaves the chamber. The sensor should be fitted inside or over the appliance casing in the normal manner. Oil supply pipework in a building or structure (including domestic garages) must be treated as internal pipework and run in a fire resistant manner.

Further guidance may be obtained from OFTEC Technical Book 3.

8.3.4.13 Oil tank support

The need to provide suitable bases and supports for domestic oil storage tanks is of paramount importance for reasons of both safety and environmental protection. Detailed guidance on the types of base materials can be obtained from BS 5410-1 and OFTEC Technical Book 3.

On exposed sites, and in particular when the tank is on piers, it is recommended to provide tank restraints this offers stability for when the tank contains small quantities of fuel.

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8.3.4.14 Steel oil storage tanks

Bottom outlet domestic steel oil storage tanks are normally supported on piers where a gravity supply is required. The piers have to maintain the tank at a sufficient height to feed the burner and to enable access to be gained for painting. Piers should be built on a concrete base extending at least 300 mm on all sides and be of adequate strength and extent to suit the nature of the ground.

8.3.4.15 Plastic oil storage tanks

Plastic oil storage tanks should be placed on a firm level non-combustible base. This should be constructed as either a concrete slab of at least 100 mm thickness or alternatively by laying paving slabs (minimum 42 mm) laid on a compact hardcore base.

8.3.4.16 Oil supply lines

It is recommended that pipes carrying oil are installed above ground in a secure and well-protected manner. However, where this is not appropriate a buried installation may be considered.

Oil supply pipes should preferably be run in plastic coated annealed copper tube to I.S. EN 1057 but steel or approved types of plastic oil supply pipe may also be used. Plastic type oil supply pipe must only be used underground and must not be exposed. Galvanised pipes and fittings must not be used. Where steel pipe are used, they must be protected from corrosion. Screwed joints should only be made with taper threads to BS 21.

8.3.4.17 Inside buildings.

Where it is necessary to run oil supply piping inside buildings, every effort should be made to avoid the use of joints between the entry point and the boiler connection. If joints are needed, these should be of the manipulative type (soft soldered joints must not be used). Joints must be readily accessible and where concealed, must have an inspection hatch, so the joint can be inspected regularly. Where bare pipes are run internally, they should be suitably painted and protected.

8.3.4.18 Underground.

Oil supply pipes taking oil from a tank to a building that are buried below ground level must be of an appropriate material such as plastic coated copper or of the approved plastic type and be protected against accidental damage. If at all possible, joints should be avoided in underground locations. Access must be provided to any buried joints. Oil supply pipes and equipment should be regularly inspected. They should not normally share a common trench with other services. Where this is unavoidable oil pipes should be kept at least 300 mm clear of other services run in the same direction. Where oil pipes cross other services, it is sometimes necessary for the clearance provided to be less than 300 mm.

If pipes are to be directly buried, a trench depth of 450 mm is recommended. A marker tape should be laid within the backfilling about 150 mm below the surface to provide a warning that an oil supply pipe is buried beneath the tape. Records should always be kept of the route of a buried oil supply pipe.

Underground pipes must be pressure tested before they are first used and then again once every 10 years and recorded if there are no joints and once every five years if there are joints. All joints in underground pipework must be accessible for inspection and maintenance.

8.3.4.19 Oil tank fill pipe

Extended fill lines that run above ground must be installed using steel tube with a minimum size of 50 mm diameter which is adequately supported with clips or brackets. Where the oil storage tank is located lower than its filling connection, care must be taken to ensure that the pressure head of oil applied during filling is not excessive and should be arranged to be self-draining, preferably into the oil storage tank. Where the oil

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storage tank is located higher than its filling connection a non-return valve should also be installed at the fill point.

Where the use of an extended fill pipe means that the delivery driver cannot see the oil storage tank it should be provided with secondary containment and an overfill prevention device. Remote monitoring gauging is also recommended.

Where it is unavoidable to run a extended fill lines through buildings great care needs to be taken to design out any risk of oil contaminating the building structure and should be run in concealed positions. It should be of heavy-duty steel constructed to BS 1387, with access for joints. Consideration should be given to running the pipe through an oil proof sleeve incorporating a leakage detector. Where pipes pass through the walls of buildings it is recommended that they are protected with an oil resistant sleeve, such as painted steel. No joints should be contained within the sleeve.

Extended fill lines should terminate with a non-return valve (where lower than the tank), isolation/gate valve, 50 mm BSP (parallel thread) connection point with weep hole and screwed cap.

8.4 Oil-fired hot water and space heating systems

8.4.1 General

This clause provides guidance on the specification of oil fired space heating and hot water systems in dwellings to meet the Building Regulations energy efficiency regulations. The appliance selected must be able to meet the calculated space and water heating loads under the specified condition as per I.S. EN 12828 and I.S. EN 12831. This clause provides guidance on the specification of oil-fired wet central heating systems for dwellings. All appliances shall be installed by a competent qualified person and the installation should follow the manufacturer's instructions and comply with all other relevant parts of the Building Regulations and for wet systems.

The guidance in this clause applies to systems fuelled by oil. The following types of oil-fired heating systems are addressed:

wet central heating systems,

range cookers with integral central heating boilers,

vaporising appliances providing secondary heating or hot water, and

fixed independent space heating devices.

Where appropriate, it may be necessary to refer to the clauses in this guide covering community heating, underfloor heating, heat pumps, solar water heating and micro-CHP.

It is recommended that all electrical works are carried out to the National Rules for Electrical Installations by a competent qualified person.

8.4.2 Oil boiler location.

8.4.2.1 Under-stairs installations

If no alternative location is available, the boiler can be located in an under-stairs space where the premises do not exceed two stories. It is recommended that a balanced flued type boiler is used in this type of location. It must be enclosed in a 30 minute fire compartment ventilated from the outside. A notice stating that the compartment is to be used for nothing but the boiler is to be placed on the door, which is to be of the self closing type. Reference should be made to BS 5410-1.

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8.4.2.2 Bedroom and bathroom installation

Bathrooms - Conventional (Open) flue boilers, which draw their air from the room in which they are located, must not be located in bathrooms. Only fanned flue or room sealed boilers can be fitted in bathrooms. A room sealed boiler can only be located in a bathroom if it is unable to be touched by anyone when standing in the bath or shower. If it cannot, then a suitable compartment within the bathroom is required to accommodate the appliance.

Bedrooms - Conventional (Open) flue boilers, which draw their air from the room in which they are located, must not be located in bedrooms. Only fanned flue or room sealed boilers can be fitted in bedrooms. Some element of noise is always generated from boilers, when in operation and this should also be considered.

8.4.2.3 Attic/loft installations

In exceptional circumstances, where there is no other possible installation location, a boiler can be located in the attic/loft space. Special reference must be made in all cases to BS 5410-1 and to include the oil supply pipework. It is also advised that the house insurers and local fire authority should also be consulted.

8.4.2.4 Garage installations

It is recommended that only room sealed balance flued appliances are installed in garages to rule out the risk of ignition of petrol vapours and the contamination of combustion air supplies from exhaust gases. If there is a risk of the boiler being damaged by a vehicle, some protection must be provided. Room should also be left for servicing to take place at the front of the boiler or at other points as required by the manufacturer. Reference should be made to Part J of the building regulations.

8.4.2.5 External boiler installations

Consideration is needed with the safety of the installation (including electrical), commissioning and service technician who has to work on the appliance. When installing external boilers special attention should be made to the following points:

overhanging foliage from trees, etc may cause stagnation and prevent dispersal of products of combustion,

adjacent buildings or structures may cause stagnation and prevent dispersal of products of combustion,

the risk of down draught from prevailing winds hitting adjacent buildings or structures which may cause stagnation and prevent dispersal of products of combustion,

oil storage tanks should be at least 1,8 m away from its flue terminal. This distance is measured from the appliance flue terminal, not the appliance itself, and

the final direction of discharge from the flue terminal so as to avoid noise nuisance complaints noise.

8.5 Oil fired wet heating system

The guidance in this clause applies to the following:

a) the specification of central heating systems in new dwellings – in this clause this is referred to as a new system

b) the specification of central heating systems in existing dwellings where previously space heating was not provided by central heating - in this clause this situation is also referred to as a new system.

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c) the specification of a replacement central heating system and/or component in existing dwellings where central heating is already installed - in this clause this situation is referred to as a replacement system.

In situations (a) and (b) above the guidance for compliance of new systems (in new and existing dwellings) with Part L are the same.

In situation (c) above, that is for replacement systems in existing dwellings, in most cases the guidance for compliance Part L is as new systems, unless otherwise stated in the relevant clause.

Oil fired central heating systems which are provided as new systems or replacement systems in dwellings should be fully pumped with a maximum heating zone of 100 m2 and meets all of the following conditions:

the boiler should have a minimum efficiency (as defined by its HARP value) of 86%, and should be a condensing type bolier.

the minimum provisions for system circulation as given in the Table 9 (row b) of the ‘Heating and Domestic Hot Water Systems for dwellings – Achieving compliance with Part L 2008’ available on www.environ.ie,

the minimum provisions for hot water storage and labelling of storage vessels as in Table 9 (row c) of the ‘Heating and Domestic Hot Water Systems for dwellings – Achieving compliance with Part L 2008’ available on www.environ.ie,

the minimum provisions for system preparation and water treatment as given in Table 9 (row d) of the ‘Heating and Domestic Hot Water Systems for dwellings – Achieving compliance with Part L 2008’ available on www.environ.ie, and

the minimum provisions required are of a boiler interlock, time control, zoning and temperature control of the heating and hot water circuits. Independent time controls for the central heating and domestic hot water.

An acceptable alternative to these is any boiler management system that delivers the specified zoning, timing and temperature and boiler interlock control provisions. Pipework should be insulated as described in Table 11 of the ‘Heating and Domestic Hot Water Systems for dwellings – Achieving compliance with Part L 2008’ available on www.environ.ie. The system should also be commissioned so that at completion the system and its controls are left in the intended working order and operate efficiently. The proper commissioning of oil fired appliances and the heating system to which they are connected and it is also a requirement that the provisions of operating and maintenance instructions are to be handed over to the customer.

8.5.1 Service and maintenance

Regular maintenance of oil fired appliances by a competent qualified person is vitally important. This work requires the use of proper combustion efficiency testing equipment. A boiler service is normally required every year, but for some appliances, six monthly attention is recommended by the manufacturer.

In order to ensure efficient combustion, the correct combustion ratio shall be in line with manufacturers instructions.

8.5.2 Range cooker boilers

Range cookers with integral dedicated central heating boilers of both pressure jet and vaporising types have been developed to the point where they can accept the heating loads of most domestic properties. On many models, the space heating output is completely independent of the cooking service. This enables the cooker to be incorporated in a fully automatically controlled central heating system. Other cookers are available with smaller output boilers that, apart from cooking, provide domestic hot water service plus towel rail only.

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Due to the nature of the operation of these appliances, system layout and control requirements are often appliance specific for both operational and reason of safety. Specific requirements should be obtained from the manufacturer at the design stage. However, the system design for safety is appliance specific. Therefore, it is strongly recommended that technicians undergo manufacturers appliance and equipment dedicated product training to further their knowledge and understanding of specific appliance related requirements.

Figure 10 — Typical open vented system

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Figure 11 — Open vented system

8.6 Room heaters (stoves)

Oil fired room heaters are available with decorative effect fires burning oil through imitation coals behind a glass front. Some of these have back boilers capable of providing a heating and hot water service. These appliances are commonly of the vaporising type. Due to the nature of the operation of these appliances, system layout and control requirements are often appliance specific for both operational and reason of safety. Specific requirements should be obtained from the manufacturer at the design stage. Vaporising stoves are designed to operate continuously and when fitted with a boiler it is necessary to provide a permanent heat load of sufficient size to dissipate heat produced by the boiler when operating on minimum output. No thermostatic radiator valves are permitted on this circuit.

It is strongly recommended that installer technicians undergo manufacturer's appliance and equipment dedicated product training to further their knowledge and understanding of specific appliance and system related requirements.

8.7 Liquefied petroleum gas (LPG)

There are two forms of liquefied petroleum gas - propane and butane. The principle difference is that propane has a much higher rate of vaporisation from its liquid state at low temperatures, which makes it particularly suitable for outdoor use and storage. It is stored in portable cylinders or bulk tanks.

The greater vaporisation rate of propane is due to the low boiling point of the gas -42oC unlike butane with a boiling point of -2oC. As Ireland never experiences temperatures as low as -42oC during the winter, a correctly sized propane storage tank will continue to deliver an adequate off-take capacity.

Butane is the most popular fuel for use indoors for cooking and cabinet heaters. It is also used outdoors in the summer months for small portable appliances such as barbeques.

LPG tanks shall only be installed by a LPG operator. For details on sizing the supplier should be contacted and I.S. 3216 referred to. For siting and other matters refer to I.S. 813.

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8.8 Condensing Boilers

Condensing boilers are the most efficient heating boilers you can buy and can convert up to 96% of fuel into heat by capturing the heat normally lost in waste gases. When gas or oil is burned carbon dioxide and water are produced. In a conventional boiler, the products of combustion are expelled to the atmosphere at high temperature (about 150°C) through the flue or chimney. At this temperature the water produced by combustion is in the form of vapour which ends up in the atmosphere. About 20% of the total heat produced by burning the fuel is wasted in this way.

A condensing boiler has a much more efficient heat exchanger which extracts the maximum amount of heat from the burned fuel. The flue operates at a temperature close to the return water temperature of the central heating system. In practice this will vary from 30°C to 85°C. When the flue products are cooled to about 55°C, the water produced by combustion begins to condense out resulting in even more energy recovery. A condensing boiler wastes only about 5% of the fuel compared to 20% for a conventional boiler.

This process produces a condensate liquid which must be removed from the boiler via a condensate drain.

Because the boiler absorbs much of the heat normally given off in the flue gases it uses less gas/oil and reduces the C02 into the atmosphere.

8.8.1 Design Considerations

Essential factors to be considered when installing condensing boilers include the following:

a) Condensate discharge pipe - this should be run in plastic pipe with a continual fall to a gully trap or a purpose made soakaway. Copper pipe is not recommended for this as the aggressive nature of the liquid will attack the copper and cause corrosion over a period of time. Refer to manufacturer’s guidelines.

b) Flueing - The flue shall be a “wet” flue system suitable for a condensing application. Check with the boiler manufacturer instructions for compatibility with the boiler connection as this connection must be a water tight seal as well as air tight seal. Also the boiler manufacturer’s instructions shall be followed when determining the minimum flue diameter and maximum flue lengths.

Consideration should be given to the flue termination point. The flue should slope back towards the boiler (2.5oC) so that any condensation forming in the flue ducts can trickle back towards the boiler and be expelled out through the condensate drain. The flue termination point needs careful consideration because of the very low temperature of the flue gases. Pluming from the flue will be more evident than from a non-condensing boiler. Even when the weather is warm, this plume may become a nuisance to neighbours, drifting across their garden or into the side of the property. To prevent these flue issues becoming a nuisance, again follow the manufacturer’s instructions and guidelines for installation. In addition, re-directional pluming kits should be available from the manufacturer.

c) Heating Emitters - traditional systems operate with a flow and return temperature difference of 11oC. Condensing boilers operate more efficiently when the return temperature is kept below 55oC to achieve this, a 21oC difference between the flow and return is recommended. This may require larger surface emitters operating at lower temperatures.

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9 Central Heating Distribution System

9.1 Pipework

9.1.1 Pipework general

All pipework material and methods of jointing shall comply with the current Irish Standards (I.S) / European Standards (EN) for low pressure domestic central heating systems, an extensive but not exhaustive list is provided in clause 2.

Pipework for domestic central heating systems includes the fuel supply pipework where appropriate. All pipe work shall be installed as neatly, unobtrusively and concealed where possible. Where mild steel tube and malleable cast iron or steel fittings are used on direct hot water services, these shall be galvanised.

Where practical, a two pipe system of pipework should be adopted. Where a single pipe system is used the heat emitter sizes shall be calculated on the basics of temperature distribution around the circuit.

Distribution pipework should be sized so that the water velocity does not at any point exceed 1,2 m/s for small bore and 1,5 m/s for micro bore. Plastic pipes or similar shall not be connected or used within 1,5 m of a heat generator unless the manufacturer permits such connections.

9.1.2 Jointing & bending

Manufactures instructions and appropriate standards shall be followed to ensure safe and leak proof joints for;

pipes conveying water for the purpose of central heating, and

pipes conveying fuel to the heat generators.

Concealed pipework will be jointed by means of non-mechanical pipe joints i.e. soldered or welded.

Recognised methods of bending steel, copper and metallic pipe shall be used to avoid reduction in pipe diameter.

When bending polyethylene pipes or similar, care shall be taken to avoid too small of a radius leading to the possible collapse of the bend when heat is applied. Minimum radius shall be 12 x external pipe diameter, i.e. 22 mm pipe X 12 = 228 mm radius.

Where soldered joints are used, flux should be applied sparingly and not excessively. When the joint is completed the residue flux shall be removed by the used of a wet cloth and the system pipework shall be chemically flushed before being put into service.

9.1.3 Pipework support & expansion

Pipework shall be adequately supported with properly made brackets and hangers at suitable intervals to permit expansion and avoid sagging. Provision shall be made for the expansion of pipework especially in the case of polyethylene and similar material. Plastic pipework and similar shall be installed and supported throughout its entire length so as to prevent sagging and the formation of high points. All high points shall be adequately vented.

9.1.4 Pipework protection

Where pipes transverse through a wall or similar they will be sleeved for the length of the structure they are passing through. Additional protection shall be applied to pipework vulnerable to mechanical or corrosive damage. Pipes shall be corrosion protected when buried in a solid concrete floor except where they are being

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used for the purpose of underfloor heating. Pipework in a fireplace/builders opening shall also be protected against corrosion.

Pipework shall not be installed;

through a damp-proof membrane,

in the cavity of cavity walls, and

under load bearing walls or structures

Pipework shall rise vertically behind dry-lining and shall be mechanically protected. For detailed instructions refer to I.S. EN 1264 (all 4 parts).

9.2 Pipe sizing

Domestic central heating pipework shall be sized so that each part of the circuit will deliver the desired output. The water velocity should not exceed 1,2 m/s for small bore and 1,5 m/s for micro bore. Pipework sizing shall be calculated using a recognised method in accordance with BS 5449. Sample method of pipe sizing may be found in the ‘Heating Design Guide’.

9.3 Pipework insulation and frost protection

9.3.1 Insulation general

Pipe work shall be insulated to;

minimise heat loss,

protect against frost damage, and

avoid creating condensation

All pipework shall be insulated unless the heat loss from the pipe makes a calculated contribution to the heat requirement to the room or space. Pipework within the habited space of the building or within dividing walls or floors in the habited space may be considered to be useful heat gains.

All pipework and fittings in un-heated areas shall be protected from frost damage. All insulation material shall be suitable for purpose, resistant to damage by insects/vermin and where exposed to the elements, shall be rendered waterproof.

Heat transfer between heating pipework and cold water supply pipes shall be avoided by maintaining adequate separation to avoid condensation. Where both services run adjacent to each other, the pipes should be insulated. Where the pipes run along a wall or skirting the heating pipes should be located in the upper most position to avoid heat transfer to the cold service.

9.3.2 Insulation of heating circuit pipework

The thickness of the insulation required by building regulations is equal to the outside diameter of the pipe (up to a maximum of 40 mm) provided that the thermal conductivity of the insulation material does not exceed 0,045 W/(mK).

The hot pipes connected to the hot water storage vessel including the open vent pipe and primary flow and return to the heat exchanger, shall be insulated 1 m from their point of connection or to the point at which they become concealed. The insulation should not be less than 15 mm of a material having a thermal conductivity of 0,045W/(mK)or equivalent.

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9.3.3 Boiler frost protection

If the heat generator and associated pipework are sited in an unheated space where the temperature may fall below 4oC, a frost stat shall be connected to bring the system into operation in the event that the temperature falls below 4oC.

9.4 Circulators

9.4.1 Pumps General

Pumps shall be fitted in accordance with the manufacturer's instructions. A pump should not be placed at the lowest point of the system where it may collect sludge. A pump shall not be located at the highest point of the system where it may collect air. Where practicable, a pump shall be fitted on a vertical pipe and with the shaft in a horizontal position.

A pump may be sited on either a flow pipe or return pipe. Care shall, however, be taken to ensure that, in conjunction with the pipework configuration, pitching or the creation of sub-atmospheric pressures in pipework will not occur. Pumps should be reasonably quiet in operation.

It shall be possible to maintain, repair or replace pumps without draining down the system. This may be achieved by installing an isolating valve and union or flange on the suction and delivery connections of each pump and by sitting the pump in a readily accessible position. Such fittings also facilitate the venting of air entrained in the vicinity of a pump

9.4.2 Duty and operation

The pumps shall be of the duty required to circulate the volume flow rate of water required at the design output conditions against the maximum resistance encountered in the heating circuits. The pump shall be capable of operating at the maximum pressure and temperature of the system. Variable head pumps shall be set to suit the system characteristics.

The pipe sizing calculations provide the necessary information to select a suitable pump to meet the system requirements. Where a system boiler is used with an integral pump that will not meet the system requirements, a mixing header should be installed with suitable pumps on each circuit.

9.4.3 Electrical connection

Any pump which is not electrically interlocked with the burner shall be capable of isolation from the electrical supply by means of a suitably fused plugged connection with socket indicator light.

Should a pump be controlled by a thermostat and/or time switch, all items shall comply with the electrical requirements of ETCI and manufacturers instructions.

9.4.4 HARP rating

Central heating circulation pumps shall be no less than B rated within the HARP range.

9.5 Open vented feed and expansion systems

9.5.1 Open vented systems General

Each heat generator shall be connected to a feed and expansion cistern by means of a cold feed and open vent pipe. Open vented systems shall incorporate a hi-limit thermostat with manual reset to ensure safe operation

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9.5.2 Feed and Expansion Cisterns

Feed and expansion cisterns shall be used exclusively to accommodate the expansion of water and to supply make-up water to the heating system. Feed and expansion cisterns for open systems shall be made of material suitable for 120°C water temperature and comply with relevant Irish/European Standards, British Standards and local authority bye-law requirements.

Feed and expansion cisterns shall be adequately supported, and should be located so as not to interfere with the insulation or servicing of the cold water service cistern. Each feed and expansion cistern shall have a suitable cover, perforated only for vent pipe discharge, and have sufficient clearance above to permit overhead passage of the vent pipe and servicing of the ball valve.

Feed and expansion cisterns likely to be subjected to frost shall be insulated with not less than 25 mm of non-combustible insulation on the cover and sides. Where located in a roof space with insulation on the roof space floor, the floor area directly underneath the cistern shall not be insulated.

A feed and expansion cistern shall have a capacity to water line of not less than 18 l when cold.

9.5.3 Cold mains water supply

A permanent cold water pipe of not less than 13 mm internal diameter shall be run from the main water supply and connected to each feed and expansion cistern by means of a stop cock complying with BS 1010-2. The cold water service to the heating system shall not in any manner interfere with the mains water supply to the cold water storage cistern or cisterns. A float operated valve (ball cock) shall be fitted to each feed and expansion cistern at the highest point practicable. The ball cock float shall be of a material suitable for operating at temperatures up to 100°C. Float operated valves shall be of a pattern acceptable to the local authority and shall comply with BS 1212-1. The ball cock float position shall be set to shut off the valve when the water in the system is cold. The ball cock float position shall be set to provide a cold water level sufficiently low to accommodate an expansion in volume of 1/20th the total water content of the heating system when operating at full heating capacity, and so that the water level does not rise to a level closer than 25 mm below the outlet of the overflow warning pipe

9.5.4 Overflow pipes

From each feed and expansion cistern an overflow warning pipe of not less than 19 mm internal diameter shall be run to discharge at the outside of the building in a visible position and shall comply with local authority requirements in respect of size and position of discharge.

The overflow pipe shall be of a material suitable for operating at the maximum design temperature of the system.

The overflow pipe shall be properly supported throughout its length and shall run with a continuous fall from the feed and expansion cistern.

For new buildings overflow pipes shall run independently from each cistern.

For existing buildings with cast concrete ring beams, to avoid structural damage, overflows may be connected at low level in roof space before exiting to atmosphere.

The overflow pipe shall be checked for proper operation at the commissioning stage.

9.5.5 Cold feed make-up

A cold feed make-up water pipe shall be connected from each feed and expansion cistern directly into the system. Where the cold feed enters the system is deemed the neutral point. The connection position shall be such as to ensure that water is not pumped out of the vent pipe and that sub-atmospheric pressures do not occur in the system under any operating condition. The cold feed make-up water pipe shall have no other

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connection and shall not supply water for any other purpose. The cold feed make-up water pipe shall be not less than 13 mm in internal diameter and made from a non-ferrous or ferrous metal.

It is recommended to fit a valve to the cold feed make-up pipe. A permanent label, ‘warning cold feed to heating system, do not close’ shall be fixed to the valve.

9.5.6 Open vent pipe

An open vent pipe shall be taken directly from each heat generator or from the highest point on the primary or heating flow pipe. The vent pipe shall rise continuously and shall avoid horizontal runs, to discharge over and into the feed and expansion cistern at a level above the overflow warning pipe. The vent pipe shall be of not less than 19 mm internal diameter and made from a non-ferrous metal. The vent pipe shall have no reduction in diameter throughout its entire length and no valves fitted. The vent pipe shall not be used as a combined cold feed and vent pipe unless permitted by the manufacturer. Refer to manufacturer’s guidelines.

Provision shall be made for venting any other high points of heating circuits and the primary circulation to the indirect cylinder, where necessary.

NOTE Installer should be aware that all self filling systems have the potential to mask permanent leaks.

9.6 Sealed feed and expansion systems (pressurised)

9.6.1 Sealed systems general

Sealed systems shall incorporate additional safety devices to ensure safe operation;

hi-limit thermostat with manual reset,

expansion vessel of adequate capacity,

pressure gauge with a range of 0 to 4 bar that is visible at all times when filling or topping up the system.

9.6.2 Expansion vessels

Every closed system shall be equipped with a sealed expansion vessel which has an acceptance volume sufficient to accommodate at least the volumetric change in the system water volume when heated from 10°C to a maximum working temperature of 110°C. Expansion vessels shall comply with I.S. EN 13831. Selection of the correct size of vessel shall be made in accordance with the manufacturer's recommendations or calculated from

Table 13 based on the volume of water within the system. Refer to the Pressure Equipment Directive (PED).

Table 13 — Sizing of expansion vessel

Total water content of system

in litres

Vessel charge and initial system pressure

0,5 bar 1,0 bar 1,5 bar

Vessel volume shall be no less than the volumes stated below in litres

25 2,1 2,7 3,9

50 4,2 5,4 7,8

75 6,3 8,2 11,7

100 8,3 10,9 15,6

125 10,4 13,6 19,5

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150 12,5 16,3 23,4

175 14,6 19,1 27,3

200 16,7 21,8 31,2

225 18,7 24,5 35,1

250 20,8 27,2 39,0

275 22,9 30,0 42,9

300 25,0 32,7 46,8

NOTE Safety valve should be set to 3,0 bar.

9.6.3 Connection of expansion vessel

The expansion vessel shall be connected to the heating system according to the manufacturer's instructions. The connecting pipe to the expansion vessel shall be fitted in such a manner that dirt or scale cannot become deposited and air cannot be trapped or accumulate in it. The expansion vessel connection shall be positioned relative to the inlet port of the circulating, pump to ensure that the pump head is dissipated as a positive pressure throughout the heating system. It is desirable to have a cold water pressure of not less than 0,1 bar at the top of the circuit. Isolating valves and control valves shall not be fitted in pipework connecting the heat generator to the expansion vessel.

9.6.4 Filling of sealed systems

The method of filling and topping up the system must not contravene National or local authority regulations. Facilities shall be provided to facilitate the filling of the central heating system with water. Introducing water periodically to make up for the losses from a central heating system should be provided by means of a;

supply cistern, or

suitable filler pump.

NOTE Installer should be aware that all self filling systems have the potential to mask permanent leaks.

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10 System control

10.1 System controls

In order to provide an efficient heating system, controls are required to ensure that the desired temperature levels are reached in each room as and when required. The set temperatures should be achieved and maintained in all conditions including those where little or no additional heat is needed.

By improving the efficiency and response of the heating system, the selection of appropriate controls plays a large role in the reduction of energy costs associated with space and water heating. Effective control of the space heating and domestic hot water supply systems in a house will ensure that comfort conditions are achieved at the minimum cost. Heat energy should be used only when and where it is required. Additional automatic control measures that would improve the energy efficiency in the house may be identified and installed where appropriate. Where a new installation is proposed, as many as possible of the applicable energy saving control measures shown in this clause should be included.

10.2 Space heating and hot water supply system controls - compliance with building regulations.

Space and water heating systems should be effectively controlled so as to ensure the efficient use of energy by limiting the provision of heat energy use required to satisfy user requirements, insofar as is reasonably practicable.

The aim should be to provide the following minimum level of control;

automatic control of space heating on basis of room temperature;

automatic control of heat input to stored hot water on the basis of stored water temperature;

separate and independent automatic time control of space heating and hot water;

shut down of boiler or other heat source when there is no demand for either space or water heating from that source.

The following paragraphs provide guidance that is specifically applicable to fully pumped hot water based central heating systems. Where practicable an equivalent level of control should be achieved with other systems, having due regard to requirements to ensure safety in use. For traditional type solid fuel fired systems, in particular, the control system should be such as to allow safe operation of the boiler at its minimum burning rate, and to provide for any slumber load of the boiler through uncontrolled circulation to a radiator or hot water storage cylinder, or by other appropriate mechanism.

Provision should be made to control heat input on the basis of room temperature, e.g. by the use of room thermostats, thermostatic radiator valves or other equivalent form of sensing device. Independent temperature control should generally be provided for separate zones that normally operate at different temperatures, e.g. living and sleeping zones. Depending on the design and layout of the dwelling, control on the basis of a single zone will generally be satisfactory for smaller dwellings. Where the dwelling floor area exceeds 100 m2, control on the basis of two independent zones will generally be appropriate. In certain cases, additional zone control may be desirable, e.g. zones which experience significant solar or other energy inputs may be controlled separately from zones not experiencing such inputs.

Hot water storage vessels should be fitted with thermostatic control that shuts off the supply of heat when the desired storage temperature is reached.

Separate and independent time control for space heating and for heating of stored water should be provided. Independent time control of space heating zones may be appropriate where independent temperature control applies, but is not generally necessary.

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The operation of controls should be such that the boiler is switched off when no heat is required for either space or water heating. Systems controlled by thermostatic radiator valves should be fitted with a bypass or other equivalent device to prevent unnecessary boiler cycling.

The following Table 14 demonstrates the recommended minimum control package for fully pumped systems.

Table 14 — Recommended control levels for central heating systems

System Control Recommended provision for new systems Recommended provision for existing

systems

Boiler interlock • Boiler-based systems should have boiler control interlock in which controls are wired so that when there is no demand for either space heating or hot water the boiler and pump are switched off, with reference to the manufacturers instructions at all time.

• The use of Thermostatic Radiator Valves (TRVs) alone does not provide an interlock.

As defined for new systems

Space heating zones

• Dwellings with a total usable floor area of up to 100m2 shall have 1 space heating zone with timing and temperature controls

• Dwellings with a total usable floor area of greater than 100m2 shall have a minimum of 2 space heating zones each having separate with timing and temperature controls

• Sub-zoning is not appropriate in single-storey open-plan dwellings in which the living area is greater than 70% of the total floor area

As defined for new systems except where the boiler only is replaced, in which case reasonable provision for a space heating system would be to control one zone

Water heating zones

• All Dwellings should have a separate hot water zone in addition to space heating zones.

• A separate hot water service zone may not be required if hot water is produced instantaneously such as with a combination boiler.

As defined for new systems

Time control of space and water heating

Time control of space and water heating should be provided by:

i. A full programmer with separate timing to each circuit;

ii. Two or more separate timers providing timing control to each circuit; or

iii. Programmable room thermostat(s) to the heating circuit(s), with separate timing of the hot water circuit.

For dwellings with a total usable floor area greater than 100m2

, timing of the separate space heating zones can be achieved by:

i. Multiple heating zone programmers; or ii. A single multi-channel programmer; or iii. Programmable room thermostats; or iv. Separate timers to each circuit; or v. A combination of (iii) and (iv) above.

As defined for new systems except where only the hot water cylinder is being replaced in a replacement system and separate time control for the hot water circuit is not present. In this case it is acceptable to have a single timing control for both space heating and hot water.

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Where hot water is produced instantaneously, such as with a combination boiler, time control is only required for heating zones.

Temperature control of space heating

Separate temperature control of zones within the dwelling, should be provided, using:

i. Room thermostats or programmable room thermostats in all zones; or

ii. a room thermostat or programmable room thermostat in the main zone and individual radiator controls such as Thermostatic Radiator Valves on all radiators in the other zones; or

iii. a combination of (i) and (ii) above.

For replacement systems where only the hot water cylinder is being replaced and where hot water is on a gravity circulation system a thermo-mechanical cylinder thermostat should be installed as a minimum provision.

Temperature control of hot water service system

• Domestic hot water systems should be provided with a cylinder thermostat and a zone valve or three-port valve to control the temperature of the hot water.

• In dwellings with a total floor area greater than 150m2it would be reasonable to provide more than one hot water circuit each having separate timing and temperature controls. This can be achieved by: i. Multiple heating zone programmers; or ii. A single multi-channel programmer; or iii. Separate timers to each circuit.

• The use of non-electric hot water controllers does not meet this requirement. Also in some circumstances, such as thermal stores, a zone valve in not appropriate; a second pump could be substituted as the zone valve.

As a minimum provision a thermo-mechanical cylinder thermostat should be installed.

An acceptable alternative to these controls is any boiler management control system that meets the specified zoning, timing and temperature and boiler interlock control requirements.

A by pass valve may be fitted as an integral part of the boiler, manufacturer’s guidelines shall be referred to.

Figure 12 — Typical circuit control layout

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Figure 13 — Enhanced control functions

Additional benefits in convenience, comfort and energy consumption can be obtained by the use of enhanced control functions. Weather compensation reduces the average boiler water temperature in mild weather; this is particularly beneficial where condensing boilers are used because it reduces the return water temperature and increases the proportion of time that the boiler operates in condensing mode. Delayed start can reduce boiler firing by delaying start-up in milder weather. Optimum start will also reduce boiler firing when it is not required but can advance as well as delay start-up. Both types of control can save energy and/or enhance comfort depending on how they are set up. Narrow temperature differential thermostats reduce the temperature swing between demand and satisfaction at the thermostat and hence the variation in room temperature. This should have the effect of marginally reducing the average temperature at which the room needs to be maintained to achieve comfort, assuming that the thermostat is set on the minimum temperature maintained.

10.3 By-pass arrangements

The need for a by-pass depends on the boiler and the control system. Some boilers require circulator overrun to dissipate heat when the boiler is switched off. Controls shut down or restrict flow while the circulator is still operating, especially in systems using TRV’s and 2-port valves a by-pass is needed to provide a circulating path. A permanent by-pass shall be fitted in accordance with manufacturers instructions. A minimum of 15 mm diameter is typically required for boilers up to 18kW output and 22 mm on larger sizes.

It is recommended that an automatic by-pass valve may be used, particularly with thermostatic radiator valves or zone valves. This type of valve is set when the system is commissioned so that under normal working conditions it is either closed or partially open, depending on the application. In operation it opens when pressure increases in response to reduce flow through the circuit.

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The minimum flow rate of water through the boiler by-pass when all other circuits are closed is specified by the boiler manufacturer, probably in terms of the temperature drop across the boiler. The actual flow rate can vary between 10 l/min (0,17 kg/s) and 40 l/min (0,67 kg/s). The flow rate through the bypass will however reduce when the heating circuits are fully open. For the purpose of estimating the total flow rate the flow rate can be assumed to be 0,10 kg/s for a 15 mm pipe and 0,25 kg/s for a 22 mm pipe.

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11 Interlinking

11.1 Heat dissipation on a traditional solid fuel system

As the output to the heating circuits from a solid fuel fired heat generator can only be reduced gradually, it is therefore necessary for reasons of system safety, integrity and operation to provide for the dissipation of such heat output. This shall be achieved by means of gravity circulation through a properly sized and configured primary heating circuit. An indirect source of hot water heating by means of a primary heating circuit may serve as an adequate means of providing for heat dissipation by gravity from a solid fuel fired heat generator.

It is recommended that the heat absorption capacity of the hot water storage system is not less than 20% of the rated heat output to water from the solid fuel fired heat generator. Where it is not possible to achieve this by increased hot water storage capacity and/or increased heat transfer surface to water storage, one or more adequately sized heat emitters shall be installed in the primary heating circuit to permanently absorb excess heat (termed ‘heat leak’).

11.2 Interlinking of solid fuel fired and oil or gas or renewable—fired heat generators rationale

An open solid fuel fire, room heater, multi-fuel stove or range type cooker fitted with a back boiler can be linked to an automatic existing heating system or to a new heating system.

The existing or new central heating boiler will continue to service the system as and when required.

The hot water and radiators can be supplied by either or both of the appliances depending on the heat input needed.

The secondary heat source (normally solid fuel) can be used to heat hot water only or to supplement hot water and heating.

In linking the heat producing appliances, one appliance when operating shall not supply the second appliance with heated water when the second appliance is not in operation. Additionally, the expansion of water and surplus heat shall be handled safely.

11.2.1 System requirements

An entirely separate and independent flue shall be used for each heat generator. Each appliance shall have its own feed. This shall be achieved by splitting the single cold feed from the feed & expansion cistern and connecting at a point of equal pressure so as to eliminate inter circulation between systems via the feed & expansion cistern. It shall not be possible to isolate either heat generator from its cold feed. An independent vent pipe shall be brought from the highest point of each primary circuit served from each heat generator.

An isolating valve shall be fitted to the pumped flow or return pipe served from each heat generator so that the heat generator not in use can be isolated from the operating heating circuits. The customer shall be provided with clear written instructions on the correct operation of the isolating valves. Where an indirect hot water cylinder is served from an oil, gas or renewable fired heat generator as well as from the solid fuel-fired heat generator, a thermostatically controlled valve should be fitted in the oil or gas primary circuit. This will prevent excessive heat supply to the hot water cylinder in the event of the solid fuel primary circuit continuing to heat the hot water after the solid fuel fired heat generator has ceased fuelling and has been isolated from the space heating circuits. In no case shall a thermostatic valve be fitted so as to obstruct flow through a vent pipe.

Any motorised valves used on the solid fuel side shall be of the powered-closed (normally-open) type. The usage of special coupling units/neutralisers, etc, for interlinking pipework from separate heat generators is permitted, subject to their design and installation not contravening any of the provisions listed above.

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Systems using a solid fuel boiler shall be designed so as to ensure that all heat generated when the boiler is slumbering is dissipated.

Dissipation of heat generated when the boiler is slumbering may be ensured by installing the necessary heating surface in a gravity circuit to the cylinder and/ or radiator(s) or incorporated in a suitably designed fully pumped system with special controls. Such a circuit should not be provided with user-operated valves.

11.2.2 Gravity circulation

Where served by gravity circulation from one heat generator, the cylinder should be installed as near to the heat generator as practicable. Cylinders served by gravity circulation shall be positioned at such a height above the heat generators as to give adequate and correct water circulation and efficient heat transfer. It is recommended that the base of the cylinder is at a level at least 150 mm above the top of the heat generator. Cylinders served by gravity circulation shall be connected to the heat generators by flow and return pipes the size of which will be determined by the available circulating pressure.

In any case these shall not be less than 19 mm internal diameter throughout. Wherever practicable, primary flow and return pipes should be connected to independent tapings on the heat generator in accordance with manufacturers’ instructions. Where primary flow and return pipes operating by gravity circulation are connected to a heating circuit, an injector ‘T’ type fitting should be fitted at the return connection point to assist proper gravity circulation.

Nominally horizontal runs of gravity circulation pipework should slope upwards in the direction of the hot water cylinder at a slope of not less than 1:30.

In the case of a primary circuit served from a solid fuel fired heat generator, no valves shall be fitted in that primary circuit. Where existing pipework containing valves is used to form such a primary circuit, these valves shall be removed. A towel rail, if required, should be fitted to the primary flow and return pipes in parallel with the cylinder.

A thermostat should not be installed to control hot water storage temperature in a primary circuit served from a solid fuel fired heat generator. Notwithstanding this recommendation, specialised thermostatic control shall, where installed, be in accordance with manufacturers’ instructions.

11.3 Types of link-up

11.3.1 Direct link-up - solid fuel with gas/oil)

A copper boiler that only heats a hot water cylinder, i.e. an open system, shall have a gravity circuit.

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Figure 14 — Direct link-up for solid fuel with gas/oil)

11.3.2 Indirect link-up - solid fuel with gas/oil

A separate cylinder coil that heats a hot water cylinder via an indirect coil, with a possible heat leak radiator, i.e. an open system, shall have a gravity circuit.

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Figure 15 — Indirect link-up for solid fuel with gas/oil, diagram A

Figure 16 — Indirect link-up for solid fuel with gas/oil, diagram B

11.3.3 Completely linked systems - solid fuel with gas/oil

Most solid fuel boilers should not be installed into a sealed system. A neutraliser should be used to properly and efficiently interlink a solid fuel appliance (with integral boiler) into a heating system with an oil/gas boiler. The complete system should be open vented. The use of a neutraliser ensures the neutral point for the

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system remains at one location. Pumped or gravity fed circuits connected to the Neutraliser have no hydraulic interaction.

A solid fuel appliance (with integral boiler) must be installed with a ’heat leak’ device. Pipework should be installed in compliance with the boiler manufacturers instructions, however, the vent and expansion pipe and the gravity induced circulation pipework should be installed using a minimum of 28 mm copper pipe. The cold feed pipe should be a minimum of 22 mm diameter. The height of the expansion pipe should be maximised to eliminate the potential for pitching on system start up. A minimum of 1 m is desirable. Except where manufacturers instructions specifically state otherwise, a close coupled feed and expansion pipe may be fitted provided that there is a cold water feed path always available and the distance between the feed and expansion connections is not more than 150 mm. The ’heat leak’ is usually piped to one of the coils in an indirect domestic hot water cylinder (or any open heat emitter e.g. a radiator). The other coil may used to allow the alternative heat source (oil/gas boiler) to also heat the domestic hot water cylinder. The cylinder must be situated at a higher level than the boiler and the pipes installed so that there is a continuous rise from the boiler to the cylinder to gravity circulate the water. A safety valve must be fitted in the flow from the boiler. No other valves should be fitted in this circuit. It is good practice with larger solid fuel appliances to install a heat leak radiator also.

When a 4-pipe system is used from the solid fuel appliance i.e. 4 connections are used on the back of the appliance, two pipes are connected directly to the neutraliser and may be pumped while the other two are used for the gravity circulation circuit (see above). When 2-pipes are connected from the solid fuel appliance an injector tee should be used, as it encourages a stable flow of hot water through both central heating and domestic hot water circuits without priority being given to the stronger flow i.e. the pumped central heating circuit. In both these cases the cylinder must be mounted at a higher level than the solid fuel appliance. See diagrams below showing both these layouts.

Figure 17 — Completely linked 4 pipe system

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Figure 18 — Completely linked 2 pipe system

The system should be controlled in such a way that when the solid fuel appliance reaches temperature, the oil/gas boiler should be locked out until heat has disipated from the solid fuel appliance. Heat will be dissipated through the domestic hot water and central heating circuits. Normally a pipe thermostat should be fitted to ensure that the return water to the solid fuel appliance remains above 50

OC to avoid condensation and

corrosion of the boiler.

Except where providing useful heat, pipes should be insulated to a high standard. Particular attention should be paid to pipes on the gravity circuit.

11.3.4 Neutralising systems - solid fuel with gas/oil - Renewables with gas/oil/electric

The use of a neutralising vessel or chamber fixes the neutral point between two or more systems. Pumped or gravity circuits connected to the chamber have no hydraulic interaction, ensuring that the pumped circuit will not induce flow through a solid fuel appliance via its gravity circuit and allowing the solid fuel appliance to contribute to the central heating load. This open system shall have a gravity circuit.

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Figure 19 — Example of a neutralising system

Figure 20 — Oil/gas boiler linked with solid fuel cooker diagram A

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Figure 21 — Oil/gas boiler linked with solid fuel cooker diagram B

11.3.5 Electronically controlled link–up - solid fuel with gas/oil

A purpose built and designed system where the solid fuel appliance is piped into the central heating system via a factory built and wired control panel which allows the fire to set up its own regime of control and circulation by operating a system of pre-set thermostats and motorised valves.

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Figure 22 — Electronically controlled link up

11.3.6 Thermal store or accumulator system

A large capacity cylinder which every connected appliance heats up indirectly through heating coils or plate heat exchangers and acts as a thermal store/buffer/accumulator. The heated water is then pumped from the cylinder to the heating circuit. Domestic water is heated indirectly via the store and usually operated as an unvented hot water system.

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Figure 23 — Accumulator system

To ensure a satisfactory interlink / link-up the following factors shall be taken into account;

the priority of any design must be safety. There shall be no possible danger to persons or property arising from the way a householder may use the system, even when this is unorthodox, unreasonable or ill advised;

consideration shall be given to conservation of fuel and power;

ensure separate and suitable flues exist for each appliance being linked;

all components of the linked system shall conform to all the relevant water by-laws, building regulations, European Standards and codes of practice;

since much of the pipe work of an existing system will be concealed it shall all be located and correctly identified by whoever carries out the installation;

any solid fuel appliance shall always have a separate cold feed and vent. These shall be permanently open and unobstructed at all times i.e. no valves etc; and

for solid fuel systems the float in the feed and expansion cistern shall be made of copper.

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12 Commissioning, Handover and Maintenance

12.1 General

Commissioning is a procedure whereby a competent person, shall put into operation a system that will conform to standards, building regulations and this code of practice so that the entire system and ancillary components shall operate safely and in compliance with the manufacturers specification.

It is important to ensure that sufficient space is left for maintenance when locating the appliance. In some cases, access may be required at the top and/or rear of the appliance. This includes maintenance not only of the appliance but of the circulating pump and any motorised valves as well. Special consideration needs to be made for floor standing appliances installed in kitchens where a worktop may be required to be installed over the appliance. Special attention should be made to appliance manufacturer’s installation, service and commissioning access requirements.

Where boilers are installed externally, maintenance should not be undertaken other than in dry conditions. Boilers should not be so located that maintenance has to be undertaken from a ladder.

Planned maintenance can keep a heating appliance operating at peak performance, reducing fuel bills and saving on costly call out fees. It is recommended that all heating appliances and their equipment are serviced at least once a year or as recommended by the manufacturer. To promote safety, peace of mind, minimise fuel costs and reduce the risk of unexpected appliance breakdown for oil and gas users, it is recommended that a qualified competent technician services and inspects a heating installation at least annually.

12.2 System cleaning and power flushing

12.2.1 General

All new systems and existing systems that have replacement equipment such as boilers, pumps and radiators should be cleansed in accordance with BS 7593. This will ensure the effective removal of any excess jointing compounds, mineral oil and other contaminants from the system following installation which can affect its performance or cause component failure.

The system first will be flushed through with clean water and then a suitable cleansing additive will be added to the system. Normally after two hours each radiator will be flushed through separately and checked with a TDS meter to check ppm (parts per million) in the heating system and compared to within 10% of mains drinking water. After all the radiators have then passed, the system will be drained down and re-filled with fresh water.

On completion, a suitable inhibitor will then be added to protect the system from further or future problems. The inhibitor levels should be checked at the systems annual service and topped up if required.

It is recommended to check the manufacturer’s instructions that the chemical cleaner and inhibitor are suitable for the equipment installed. A label stating the date of application, the type and the amount of inhibitor used shall be fixed in a prominent position on the system.

It is recommended to check the manufacturer’s instructions that the chemical cleaner and inhibitor are suitable for the equipment installed. A label stating the date of application, the type and the amount of inhibitor used shall be fixed in a prominent position on the system.

12.2.2 Magnetic cleansing

Magnetic cleansing is the most effective means of carrying out a preliminary central heating system iron oxide flush where the boiler is working or a new boiler is installed.

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As a process, magnetic cleansing is carried out through the temporary installation of a portable magnetic filtration unit. This is located at a suitable point on the central heating system. The system should have an appropriate cleansing solution added in accordance with manufacturer’s instructions. The magnetic rating of the filtration unit should not be less than 10,000 gauss with a total magnetic area in excess of 34,000 mm² for maximum operational flow efficiency. The unit should include suitable isolation valves and a pressure release vent to ensure ease of cleaning during the process.

The canisters housing the magnets should have the capacity to collect at least 1,700 g of iron oxide sludge while allowing full flow through the unit. The filtration appliance should be cleaned regularly during the cleansing process, again, in accordance with manufacturer’s instructions.

Once the magnetic cleansing process has been completed, the domestic magnetic filter is re-installed to provide permanent ongoing system protection.

12.2.3 Power flushing combined with a portable magnetic filter

Power-flushing may be necessary where a working boiler/pump is not available or there is a physical blockage in the system. In this instance, a portable magnetic filtration unit can be used temporarily in conjunction with the power-flush machine to improve the effective cleansing of the system. This approach extends the life of the power-flush machine and provides visual evidence to the customer. Where such a unit is used, it should meet the standards indicated above.

The inhibitor levels should be checked at the systems annual service and topped up if required whilst the magnetic filter can be cleaned to continue full system protection.

12.2.4 Magnetic filtration

Effective ongoing magnetic filtration of central heating systems is recommended through the installation of a permanent magnetic inline filter. Ideally, the filter should be installed on the return pipework as close to the boiler as possible.

Flexibility of filter orientation during installation is essential to accommodate all existing pipework layouts.

The filter must be capable of maximising the volume of magnetite collected on first pass with a recommendation that this level achieves in excess of 90% of suspended black iron oxide. This figure should increase to virtually 100% during subsequent passes. Recommended minimum capacity for a domestic filter is 250 g of iron oxide sludge for a standard 22 mm (3/4”) system over a period of at least 12 months. For 28 mm (1”) pipework, the minimum recommended capacity is 400 g to cater for increased levels of magnetite generated on larger systems. Even at capacity, the filter must allow unrestricted flow without loss of pressure. Importantly, the filter must not be susceptible to blockage, even when full.

Domestic filter magnet strength should achieve a minimum gauss rating of 7,500 with an anticipated lifespan exceeding that of the central heating boiler.

Servicing should be straightforward with the ability to carry out a visual inspection of the inside of the canister chamber to ensure all debris has been successfully removed.

12.3 Commissioning

All new heating systems and boiler replacements must be commissioned by a trained qualified technician in accordance with the manufacturer's instructions. The central heating system should be commissioned so that the design volume flow rates are supplied to each dwelling and there is no excessive bypassing of water that would lead to higher pumping energy use. The flow rates in individual heat emitters should be balanced using appropriate return temperatures or by using calibrated valves.

The commissioning service includes pre-commissioning checks for the service systems and covers fuel supply, water, flue, electrics and controls. Boiler system checks include all connections, interlocks and safety features. The system should be filled and vented, with the necessary circulating pumps running prior to

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commencing boiler commissioning. A soundness test should be carried out on the fuel supply line and then purged before commissioning can begin. Safety systems need to be fitted and fully operational, including safety valves, fuel shut-off devices, fanned flue and/or pressurisation-unit interlocks.

On all new heating systems or where new equipment has been installed to an existing heating system, it is recommended to flush the system with a non acid based chemical to clear any solder flux residue or swarf from the pipework, radiators and boiler. The chemicals used must be suitable for the pipework and equipment.

A corrosion inhibitor shall be added to the final fill in accordance with BS 7593. It is recommended to check the manufacturer’s instructions that the chemical cleaner and inhibitor are suitable for the equipment installed. A label stating the date of application, the type and the amount of Inhibitor used shall be fixed in a prominent position on the system.

Safety valves shall not be valved and be of pre-set construction and have a minimum lift pressure of 3bar. Refer to the EU Directive, Pressure Equipment Directive (PED).

12.4 Filling all system types contain water as the transfer medium

Low temperature heating systems for domestic applications should be filled and tested to the maximum operating pressure (3bar x 1.5 = 4.5bar).

Systems which have a working pressure of 2 Bar should be tested at 3 Bar for a period of 1 hour. The pressure test shall apply only to pipe work and heat emitters. Ancillaries shall be isolated to avoid damage by inadvertent over pressurisation.

The pressure should be registered on the system pressure gauge and verified by another temporary gauge on the test appliance. A period of 10 minutes should be allowed for the contents of the system to settle, to ensure that the test has passed. When past, system flushing of both hot and cold should take place and a corrosion inhibitor should be added when complete.

12.5 System filling

12.5.1 Open systems

Following procedures carried out in section 12.3, the stop cock to the feed and expansion cistern should be opened to fill the heating system. Venting shall then take place.

12.5.2 Sealed systems

The systems shall be filled using a filler break tank and pressure pump to prevent back flow to the water main, when the cold fill pressure has been reached . Venting shall then take place and cold fill pressure set. Cold fill pressure should be set as per to manufacturer’s instructions. The filler loop shall then isolated and be disconnected from the fill point. The loop should be left with the householder for use at some time in the future.

12.5.3 Auto Fill Systems

On larger domestic installations automatic filler sets or pressurisation units maybe required, in this instance the system shall be back filled as detailed in clause 12.5.1.

The auto fill unit should be then turned on to create the required cold fill pressure.

Expansion vessels should be positioned as per system design criteria set out in domestic heating design. The vessels shall have an air pressure setting so as to enable the contents of the system to expand, while maintain operating pressure.

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A visual inspection shall be carried out to ensure that no water leaks are present and that the safety relief valve is operating within the system final working pressure.

12.5.4 Boiler firing

The heat source should be fired and commissioned as required by the manufacturer’s instructions. Flue gas sampling and air inlet settings shall be undertaken as to ensure safe operation.

The primary and secondary sides of the system shall then be balanced so as to achieve heat as required with further venting at this time.

The pump speed may require to be altered in accordance with site conditions.

12.5.5 Manuals and documentation

The systems within the dwellings should be demonstrated to the householder and suitable information provided on the operation of the controls. It is recommended that a commissioning record be made and left with the handover documentation to the householder. A full set of equipment manuals and boiler log books with a spare parts list shall be left with the house holder. A parts table should identify and list each item and its location. A list of manufacturers’ names and service contact numbers shall be included with this manual. Emergency numbers of utilities providers shall be included, e.g., gas company, fire service, electricity supplier, installation company.

This, in so far as possible, should enable those following on to safely monitor/ repair and operate the system installed.

The installer shall make himself aware of the requirements of the appropriate Building Regulations, thus ensuring correct installations so as to ensure that he does not make himself liable.

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13 Abbreviations

Below lists industry used abbreviations, not all of which are referenced in this Code but still relevant.

AAV Automatic Air Vent MPV Mid Position Valve

ABV Automatic By-Pass Valve MV Mixing Valve

AV Air Vent NRV Non-Return Valve

B Boiler OS Outside Sensor

BC Boiler Controls OSV Open Safety Vent pipe

CF Cold feed Pipe OV Open Vent Pipe

CF&V Combined feed 7 Vent pipe PG&T Pressure Gauge & Thermometer

CT Cylinder Thermostat PR Programmer (two or more Outputs)

CYL Indirect Hot Water Cylinder PRV Pressure Regulating Valve

DIV Diverting Valve PTRV Pressure & Temperature Relief Valve

DNRV Double Non-Return Valve R Radiator or other Emitter

DV Drain Valve RT Room Thermostat

ERV Expansion relief Valve RV Regulating Valve

EV Expansion Vessel SV Stop Valve

F&E Feed & Expansion Pipe TD Tundish

F&EC Feed & Expansion Cistern TRV Thermostatic Radiator Valve

FS Flow Sensor TS Time Switch (single output)

HC Heating Circulator TSU Thermal Storage Unit

HWB Hot Water Circulator TSV Temperature Safety Valve

HWC Hot Water Circulator TU Top-up Unit

IS Inside Sensor UHWC Unvented Hot Water Cylinder

IV Isolating Valve WV Radiator Wheel Valve

LSV Radiator Lock Shield Valve ZV Zone Valve (normally closed)

MBV Motorised Blending Valve DIRCYL Direct Cylinder

INDCYL Indirect Cylinder

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Annex A (informative)

Fluid categories and examples

Fluid category 1: Wholesome water supplied by a water undertaker and complying with the requirements of the national water regulations.

Water supplied directly from a water undertaker’s main.

Fluid category 2: Water in fluid category 1 whose aesthetic quality is impaired owing to-

a) a change in its temperature, or

b) the presence of substances or organisms causing a change in its taste, odour or appearance, including water in a hot water distribution system.

Mixing of hot and cold supplies.

Domestic softening plant.

Drink vending machines having no ingredients injected into the distribution pipe.

Fire sprinkler systems without anti-freeze.

Ice making machines.

Water cooled air conditioning units (without additives).

Fluid category 3: Fluid which represents a slight health hazard because of the concentration of substances of low toxicity, including any fluid which contains-

a) ethylene glycol, copper sulphate solution or similar chemical additives, or

b) sodium hypochlorite (common disinfectants).

Water in primary circuits and heating systems in a house.

Wash basins, sinks and showers.

Clothes and dishwwashing machines.

Home dialysing machines.

Drink vending machines having ingredients injected.

Hand held hoses.

Hand held fertilizer sprays.

Irrigations systems.

Fluid category 4: Fluid which represents a significant health hazard because of the concentration of toxic substances, including any fluid which contains-

a) chemical, carcinogenic substances or pesticides (including insecticides and herbicides), or

b) environmental organisms of potential health significance.

General: Primary circuits and central heating systems in other than a house.

Houses and Gardens: Mini- irrigation systems without fertilizer or insecticide application such as pop-up sprinklers or permeable hoses.

Food processing: Food preparation, dairies, bottle washing apparatus.

Catering: Commercial dishwashing machines, bottle washing apparatus, refrigeration equipment.

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Fluid category 4 (cont'd): Industrial and commercial installation: Dyeing equipment. Industrial disinfecting equipment. Printing and photographic equipment. Car washing degreasing plant. Commercial clothes washing plant. Brewery and distillation plant. Water treatment plant or softeners using other than salt. Pressurised fire fighting systems.

Fluid category 5: Fluid representing a serious health hazard because of the concentration of pathogenic organisms, radioactive or very toxic substances, including any fluid which contains-

a) faecal material or other human waste;

b) butchery or other animal waste; or

c) pathogens from any other source.

General: Industrial cisterns, non-domestic hose union taps. Sinks, urinals, WC pans and bidets. Permeable pipes in other than domestic gardens laid below or at ground level with or without chemical additatives. Grey water recycling systems.

Medical: Any medical or dental equipment with submerged inlets. Laboratories. Bed pan washers. Mortuary and embalming equipment. Hospital dialyses machines. Commercial clothes washing plant in health care premises. Non-domestic sinks, baths, washbasins and oher appliances.

Food processing: Butchery and meat trades slaughterhouse equipment. Vegetable washing.

Catering: Dishing machines in healthcare premises. Vegetable washing.

Industrial and commercial installation: Industrial and chemical plant, etc. Mobile plant, tankers and gully emptiers. Laboratories. Sewage treatment and sewer cleansing. Drain clearing plant. Water storage for agricultural purposes. Water storage for fire fighting purposes.

Commercial agricultural: Commercial irrigation outlets below ground or at ground level and/or permeable pipes with or without chemical addititives. Insecticides or fertiliser applications. Commercial hydroponic systems.

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Annex B (informative)

Electrical considerations

B.1 General

The following information is for guidance only and reference shall always be made to the current edition of the ETCI Rules. B.2 Cables and connections

a) Flexes, cables and connecting services shall be suitable for the voltages and currents involved. b) Cables supplying the double pole switch or socket shall be no smaller than 1,5 mm². The cable size shall be large enough to be adequately protected by the relevant fuse or circuit breaker at the electrical consumer unit. For example, if the supply is taken from a socket protected by a 20 amp fuse then the cable shall be at least 2,5 mm². c) PVC-PVC insulated cable shall not be used at a height of less than 1,5 m above the floor unless it is mechanically protected. NYMJ cable may be used at any height.

d) Care shall be taken not to exceed the temperature rating of the electric cables. Heat resistant types shall be used where necessary. e) Flexible trailing leads shall not exceed 2 m. f) Where 4 core cable is required, the phase shall be brown, the neutral blue, the earth green/yellow and the switched live shall be any colour except blue, green, green/yellow. B.3 Appliance and conductor protection

Appliances requiring an electrical supply shall be connected via a fused supply as indicated by the manufacturer.

The configuration of the switch and the rating of fuse shall be in accordance with the appliance manufacturer’s requirements.

Electric instantaneous showers shall be connected in accordance with the manufacturer’s requirements and ETCI rules. Care shall be taken when considering the location of the means of isolation and the type electrical protection to be provided at the consumer unit.

See ETCI rules for such switches serving appliances in rooms containing a bath or shower.

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B.4 Earth bonding

a) The ETCI Rules for Electrical Installations require equipotential bonding for extraneous metal work including gas supply, water and central heating pipes.

b) Metallic pipework shall be bonded to the main earth terminal at the electrical consumer unit using green/yellow insulated 10 mm² cable. A permanent label inscribed “safety electrical connection, do not remove” shall be permanently affixed at the main bonding connection to each engineering service.

c) Metallic appliances i.e. Cast Iron or pressed steel bath, stainless steel kitchen sink shall be bonded to the main earth terminal at the electrical consumer unit using green/yellow insulated 10 mm² cable

d) Gas Pipework shall be bonded to the main earth terminal at the electrical consumer unit using green/yellow insulated 10 mm² cable. The connection shall be made at a point within 500 mm of either (a) the outlet of the gas meter and on the outlet side, or (b) the point where the pipe enters the house, or (c) the point where the gas pipe first becomes visible in the house. It is important to ensure that such connection is not made on the upstream side of any insulating joint fitted into the gas pipe system

e) Where bonding arrangements are found to be not in accordance with the ETCI National Rules then the consumer shall be informed of the situation and advised to have the electrical installation checked and rectified by a competent person.

B.5 Testing of electrical appliances

All installations require testing before commissioning takes place both for safety and correct operation.

Tests consist of:

a) Polarity test

b) Earth continuity test

c) Insulation resistance test

d) Circuit continuity tests