water distribution and controls

Bahrain Bay Infrastructure

Technical Specifications Volume 3

Water Distribution & Collection Networks

JOB NUMBER: RI4326 DOCUMENT REF: RI4326-D905-R3-0021

2 Tender Issue SA ML ML 18/10/07 1 100% CD 2nd Stage Tender Issue SA RP HS 08/10/07 0 85% Submission – For Review SA DS HS 19/12/06 Originated Checked Authorised Date

Revision Purpose Description

BAHRAIN BAY Technical Specifications - Volume 3

Water Distribution and Collection Networks

RI4326-D905-R3-0021 of 44 18 October 2007

Contents Section Page

1 GENERAL REQUIREMENTS 5 1.1 SCOPE OF WORK 5 1.1.1 Irrigation 5 1.1.2 Potable Water and Fire Fighting 5 1.1.3 Foul Water 5 1.1.4 Storm 6 1.2 GENERAL REQUIREMENTS 6 1.3 LAYOUT OF WORK 6 1.4 CLEAN-UP 7 1.5 WARRANTY 7 1.6 TRENCHES AND OTHER EXCAVATION 7

2 SUBMITTALS 8 2.1 MATERIALS, PRODUCT DATA AND EQUIPMENT SCHEDULE 8 2.2 NO OBJECTION CERTIFICATES 8 2.3 SHOP DRAWINGS AND VERIFICATION OF DIMENSIONS 9 2.4 MANUFACTURERS’ CERTIFICATIONS 9 2.4.1 Pipes and Fittings 9 2.4.2 Valves and Special Fittings 9 2.5 RECOMMENDATION OF THE MANUFACTURERS 9 2.6 SPARE PARTS 10 2.7 INSTALLATIONS AND TESTING 10 2.8 MANUFACTURER'S LITERATURE 10 2.9 AS-BUILT DRAWINGS 10

3 PRODUCT STORAGE AND HANDLING 12 3.1 DEFINITION 12 3.2 TRANSPORTATION AND HANDLING 12 3.3 STORAGE AND HANDLING 12

4 PIPE WORKS – GENERAL REQUIREMENTS 14 4.1 GENERAL REQUIREMENTS 14 4.1.1 Standards Specifications 14 4.1.2 Scope of Work 14 4.1.3 Standards 14 4.2 MATERIALS TO BE FURNISHED BY THE CONTRACTOR 15 4.3 EXECUTION 15 4.3.1 Pipe Materials 15 4.3.2 Pipe Installation 16 4.3.3 Jointing 16 4.3.4 Excavation and Backfilling 17 4.3.5 Underground Warning Tape 17



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4.4 POTABLE & IRRIGATION PIPES AND FITTINGS 17 4.4.1 High Density Polyethylene Pipe 17 4.4.2 Jointing 18 4.4.3 Sampling and Testing 19 4.4.4 Basis of Acceptance / Rejection 20 4.4.5 Ductile Iron Pipe And Fittings 20 4.4.6 Thrust Restraints 20 4.5 PAINTING 21 4.6 PIPELINE PRESSURE TESTING 22 4.7 CLEANING 22 4.8 DISINFECTION 22

5 FOUL & STORM DRAINAGE PIPES AND FITTINGS 23 5.1 GENERAL 23 5.1.1 References 23 5.2 PIPE MARKING 23 5.3 HANDLING AND STORAGE 23 5.4 QUALITY ASSURANCE 24 5.5 UNIPLASTICISED POLYVINYL CHLORIDE (uPVC) PIPE AND FITTINGS 24 5.6 GLASS REINFORCED PIPE (GRP) & FITTINGS 26 5.6.1 Testing 27 5.6.2 Design Parameters to be Considered by the Contractor 27 5.6.3 Additional requirements: GRP Pipe Data to be Submitted. 28 5.6.4 Handling and Installation Specification 29 5.6.5 Tests for GRP Pipes 29 5.6.6 Required Pipe Data 33 5.7 DUCTILE IRON PIPE AND FITTINGS 33

6 PIPE LAYING 34 6.1 GENERAL 34 6.2 PIPE BEDDING 35 6.3 CONCRETE PROTECTION TO PIPES 35 6.4 COMPLETETION OF PIPE SURROUND 36 6.5 BACKFILLING 36 6.6 GULLIES AND DRAINAGE CHANNELS 36 6.6.1 Gullies 36 6.6.2 Pre-formed Gullies 37 6.6.3 Manhole 37 6.7 CONNECTION TO GOVERNMENT MAIN 38 6.7.1 General Requirements 38 6.8 THRUST BLOCKS 39 6.9 VALVES 39 6.9.1 General 39 6.9.2 Check Valves 40 6.9.3 Gate Valves 41 6.9.4 Air Valves 41 6.9.5 Penstocks 42



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6.9.6 Stainless Steel Penstocks 43



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1 GENERAL REQUIREMENTS 1.1 SCOPE OF WORK

The work consists of the provision of new services and comprises the installation, testing and commissioning of the following services networks as summarised below, and as per this Specification and Contract Drawings.

1.1.1 Irrigation

The system comprises of an irrigation water supply network to meet the irrigation requirements of the Bahrain Bay for a 24-hour period of irrigation demand. The irrigation network will be pumped from an irrigation reservoir (by others) located adjacent to the Sewage Treatment Plant offsite.

The reticulated irrigation supply network covers the Bahrain Bay site and is fed by a single connection across the North Manama Causeway (NMC) as per the Contract Drawings.

The Scope of Work includes the primary irrigation network, service connections, NMC crossing terminating adjacent to the offsite STP at the interface point identified on the Drawings.

The work consists of pipelines with diameters ranging from 150 mm to 300 mm.

1.1.2 Potable Water and Fire Fighting

The potable water supply requirements for the Bahrain Bay development will be supplied by MEW to the two water reserviors located within the development. From the water reservoirs, water will be distributed by pressurised system boosted through booster pumps to serve the development. The fire hydrants are installed along the network with a spacing of 150m intervals to serve the development with a pressure of 500 GPM in the event of fire. The fire pumps will be sized to supply the fire demand of 500 GPM through two fire hydrants in the event of fire with a pressure of 4 bars. The potable water network will have a minimum network pressure of 1.5 bar and a maximum pressure of 4.5 bar in the network.

The work package comprises of the installation of the primary networks contained within the development downstream of water reserviors and includes 150mm to 300mm diameter pipelines the installation of valves, service connections and appurtenances and installation of the booster pumps and fire fighting pumps.

1.1.3 Foul Water

The proposed foul water system for the Bahrain Bay development is generally a gravity sewerage system. The infrastructure works shall comprise the construction of the gravity network sewers with future stub ends located at the parcel boundaries of each development package. The sewerage network is designed to keep the network above the ground water table to avoid infiltration into the network.



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Both North and South Island will have independent foul gravity sewers and Foul Pumping Stations each from where the foul sewer will be pumped through force mains to the Sewerage Treatment Plant (by others) located offsite.

1.1.4 Storm

The Proposed Storm Water System for the Bahrain Bay development is a gravity drainage system. The infrastructure works shall comprise of the construction of gravity network drains, future stub ends located at parcel boundaries, road gullies, gully connections to the main network and oil interceptors. The Storm Water Drainage outfalls through the Quay walls have already been installed under the Marine Construction Package. These outfalls have been left with a pipe protruding out of Quay Wall’s stone backing for the Infrastructure Contractor to connect to.

The Storm Drainage Network is designed to keep the network above the groundwater table to allow the system to be a gravity drainage system. Each of the drainage runs are independent of the others and will transport the storm water to an oil interceptor before it is released into the sea.

1.2 GENERAL REQUIREMENTS Services shall be installed in a sequenced and logical manner to minimise the requirement to protect any previously installed services.

The Contractor shall include for all materials, labour, plant and tools.

Where new cable/ducts/pipes are to be laid along side, over or under the Contractor’s previously installed services, the Contractor shall take care to interfere as little as possible with the existing services and connections thereto and any damage shall be repaired by the Contractor to the satisfaction of the Engineer. Any previously installed services shall be protected before commencing earth works in their vicinity.

All concrete works shall conform to the requirements of the Technical Specifications Volume 13 Concrete.

The Contractor shall be responsible for public safety during execution of work. He will take all steps, including where necessary the provision of ropes, picket fence, etc. on each side of the trenches and excavations with warning lights and night watchman, etc. to ensure the safety of the public. The Contractor will be held responsible for any damage to property or injury to persons due to his negligence. Any instruction from the Engineer concerning the safety aspects of the work must be carried out immediately, but the Contractor shall remain responsible for the adequacy of the safety measures.

1.3 LAYOUT OF WORK The Contractor shall stake out the water systems in accordance with the design drawings. Staking shall be erected in such a manner as to ensure permanency of the staked locations until such time as the respective system is installed. Stakes shall be placed to show location of valves, pipelines and control head. Stakes shall be flagged with bright flagging for ease of



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location. All staking by the Contractor shall be subject to agreement of the Engineer. Any stakes disturbed by other works shall be reinstated by the Contractor as early as practicable in the circumstances.

1.4 CLEAN-UP During the course of construction, the Contractor shall remove waste material from the site continually as is necessary to keep the site in an orderly manner. Waste material shall be removed from the work site and not to be used as back-fill material. Upon completion of the Contract, the Contractor shall remove all waste equipment and parts and leave the site in a neat and orderly condition.

1.5 WARRANTY All work included under this Contract shall be warranted by the Contractor against all defects and malfunction of materials and workmanship for a period of one year from the date of completion of works. Should problems arise with the system during the warranty period, all necessary repairs and/or replacements shall be made by the Contractor in an expedient manner at no additional cost to the Employer.

1.6 TRENCHES AND OTHER EXCAVATION All trenches and other excavation shall be maintained in a dry condition and the Contractor shall arrange a suitable dewatering system for any dewatering involved, in agreement with the Engineer, to keep the working place clean and dry. The Contractor shall be deemed to have included in his rates for all costs associated with this work.



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2 SUBMITTALS The Contractor shall order materials to suit the construction programme and shall plan his necessary submittals to the Engineer in accordance with the Technical Specifications Volume 1 General in a timely manner to suit the ordering, delivery and construction timing requirements. The Contractor shall submit as a minimum the following documents for review by the Engineer:

2.1 MATERIALS, PRODUCT DATA AND EQUIPMENT SCHEDULE All specifications, diagrams, samples, drawings and such other data shall be provided by the Contractor, in a format to be agreed with the Engineer, which may be required to demonstrate compliance with the specification. This shall include but not limited to the following information:

- Originals of catalogues and engineering data sheets for manufactured items; each item and option to be provided shall be clearly marked and each item not to be provided shall be deleted.

- Literature to show that products provided meet the requirements for material, construction, operation, and testing.

- Information on the following items as a minimum: pipes; pipe jointing systems, manhole covers and frames and gully covers, gratings and frames.

- Manufacturer’ s installation instructions for all items.

- Certified reports for all tests and inspections designated herein, signed and sealed, showing full compliance with referenced standards.

- Maintenance requirements and procedures.

- Period of guarantee for products.

2.2 NO OBJECTION CERTIFICATES Prior to start of any work on government property the Contractor has to approach all relevant Service Authorities in Bahrain to get their no objection for the work included in this contract and a record drawings for their existing services. Copy of these drawings and no objection certificate should be submitted to the Engineer before starting the actual work at site. In addition, for work on Bahrain Bay development land the Contractor shall make all necessary submissions to the Ministry of Water and Electricity, EDD to obtain their no objection certificate ensuring that the works covered by this Specification will not invalidate the adoptability of the High and Low Voltage networks within Bahrain Bay.

All the works executed in Bahrain Bay should be in compliance with the requirements of MEW and MoWH of Bahrain unless specified otherwise in the Technical Specifications and Drawings.



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2.3 SHOP DRAWINGS AND VERIFICATION OF DIMENSIONS The Contractor shall prepare Shop Drawings including but not limited to the following information

- Profiles of each pipe system including chainage, ground levels, invert levels, critical clearances and position of pipework structures.

- Material, class, grade, joint type, pressure rating, dimension, location and identification number of each pipe and pipe fitting to be furnished and installed.

- Procedures for building pipes into concrete structures.

- Procedures for encasing pipes in concrete.

- Class, dimensions, location and identification of each manhole cover and frame to be furnished and installed.

- Procedures for placing and fixing manhole covers and frames.

- Class, dimensions, location and identification of each gully cover, grating and frame to be furnished and installed.

- Procedures for placing and fixing gully covers, gratings and frames.

- Details for handling and storage of pipes, manhole covers and frames and gully covers, gratings and frames.

- All other miscellaneous details required for complete installation.

The review of Shop Drawings by the Engineer shall not relieve the Contractor of any of his responsibility under the contract for successful completion of the work.

2.4 MANUFACTURERS’ CERTIFICATIONS

2.4.1 Pipes and Fittings

Certification by a recognised certification mark scheme such as "The Kitemark" or by an independent third party testing organization to the satisfaction of Engineer that production has been carried out under a system for supervision, control and testing, applied during manufacture, in accordance with Bahrain and British Standards or an equal procedure.

2.4.2 Valves and Special Fittings

Manufacturer's certificate for pressure testing, and coating, including holiday and DFT test reports for each valve, fitting, spool if applicable.

2.5 RECOMMENDATION OF THE MANUFACTURERS The Contractor shall submit manufacturers' recommendations for installation and commissioning of each material or piece of equipment prior to commencing work. Recommendations shall include testing methods, storage requirements and maintenance and operational data. The Contractor shall have a copy of the manufacturers' instructions



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available on site at all times while work is in progress and shall follow these instructions unless otherwise authorized to deviate by the Engineer.

2.6 SPARE PARTS The Contractor shall submit manufacturer's list of spare parts prior to commissioning any piece of equipment. Recommendations shall include stocking recommendations, exploded assembly diagrams illustrating location and spare parts to be utilised and all relevant operational data.

2.7 INSTALLATIONS AND TESTING The Contractor shall submit his proposed work method statement prior to commencing work. The statement shall detail proposed sequence of work, hold points, testing frequency and document control.

2.8 MANUFACTURER'S LITERATURE At such time as the list of materials has been accepted by the Engineer, the Contractor shall provide six (6) sets of manufacturer's technical & maintenance literature including M&E specifications to the Engineer including an electronic copy in PDF format. Data sheets shall provide sufficient technical information to identify each product and shall include the name and the address of the nearest supply firm, which should have a local representative in Bahrain.

2.9 AS-BUILT DRAWINGS The Contractor shall maintain one set of contract drawings for the sole purpose of recording accurate changes made as the work progresses ("As-Built" conditions) of the water systems. All changes previously agreed with the Engineer and all completed work shall be recorded on these drawings.

The Contractor shall prepare as-built drawings clearly showing all location, depths, slopes, heights, shapes and dimensions of all works as executed. All valve locations and piping shall be dimensioned and recorded. The Contractor shall submit as-built drawings for all electrical installations.

Sizes of all the as-built drawings should be in accordance with MEW-WDD and MoWH-SDD Standards.

Contractor shall prepare and submit as-built drawings for the pipeline profiles. Pipeline profile drawings shall be in Horizontal scale of 1:1000 and Vertical scale of 1:100. Pipeline profiles shall be submitted on separate drawings with clear references to layout drawings marked on the same.

Chambers Schedule shall be prepared indicating all relevant construction items and giving co-ordinates for each manhole in compliance with Bahrain grid System.



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The Contractor shall submit as-built drawings for all the electro-mechanical installations. All details of the installed equipment regarding Manufacturer, and Model No., Type, size, etc., shall be provided in the legend of the drawings.

After final acceptance of the As-Built Drawings, the Contractor shall submit the required sets, as specified in the Technical Specifications Volume 1 General.



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3 PRODUCT STORAGE AND HANDLING 3.1 DEFINITION

Products mean new material, machinery, components, equipment, fixtures, and systems forming the Work. It does not include machinery and equipment used for preparation, fabrication, conveying and erection of the Works. Products may also include existing materials or components required for re-use.

The Contractor shall not use materials and equipment removed from existing premises, except as specifically permitted by the Engineer or provided in the Technical Specifications.

The Contractor shall provide interchangeable components of the same manufacturer, for similar components.

3.2 TRANSPORTATION AND HANDLING All products shall be delivered in the manufacturers' original protective packaging and shall be inspected at time of delivery. Any products, which are damaged and not in accordance with specifications, or date stamp expired, shall be immediately removed from the site and replaced.

The Contractor shall promptly inspect shipments to assure that products comply with requirements, quantities are correct, and products are undamaged.

Evidence must be submitted to verify that materials have been properly protected during transport and storage prior to delivery to the site.

All products shall be handled and stored in accordance with printed recommendations of the manufacturer.

The Contractor shall be responsible for transport of pipes from the manufacturing plant to the site storage yard for proper stockpiling. Every shipment, upon reaching the storage yard shall be subjected to one hundred percent (100%) visual inspection. If more than two percent (2%) of the pipes shipped are found with visible damage, a representative sample equivalent to five percent (5%) of the lot, selected at random, shall be subjected to hydrostatic test at 1.0 MPa (150 psi), the pressure maintained for thirty (30) seconds. Any pipe failing this test shall be immediately removed from site. If twenty percent (20%) or more of the five percent (5%) samples fail, the whole lot shall be subjected to hydro test. Any pipe failing this test shall be immediately removed from site.

All pipe and accessories shall be stored on flat, level ground with no rocks or other objects under the pipe. The maximum recommended stacking height for HDPE pipe shall be in accordance with the manufacturer’s recommendations.

3.3 STORAGE AND HANDLING The Contractor shall store and protect products in accordance with manufacturer's instructions, with seals and labels intact and legible and store sensitive products in an appropriate manner whether shaded, weather-tight, climate controlled or the like.



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Fabricated products stored externally shall be placed on pallets or other means of above ground storage.

The Contractor shall provide off-site storage and protection when the site does not permit on-site storage or protection.

The Contractor shall cover products subject to deterioration with impervious sheet covering and provide ventilation to avoid condensation.

The Contractor shall provide equipment and personnel to store products by methods to prevent soiling, disfigurement, or damage.

The Contractor shall arrange storage of products to permit access for inspection and shall periodically inspect producte to assure that the products are undamaged and are maintained under specified conditions.



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4 PIPE WORKS – GENERAL REQUIREMENTS 4.1 GENERAL REQUIREMENTS

4.1.1 Standards Specifications

This section deals with the specification for works to be carried out in connection with Water Services pipe work.

All pipe material used for constructing the potable water distribution network and irrigation water distribution network should be of HDPE fit for respective use and from a manufacturer agreed with the Engineer.

General requirements for the potable water and irrigation water works shall conform to the Ministry of Electricity and Water (MEW), Water Distribution Directorate and the Ministry of Works and Housing (MoWH), Sewerage and Drainage Directorate specifications respectively and the specific requirements of this Technical Specification.

Foul water network pipe material for diameters up to and including 300mm should be of uPVC capable of handling foul sewer, fit for respective use and from a manufacturer agreed with the Engineer. Foul water network with pipe diameter above 300mm should be of GRP capable of handling foul sewer water, fit for respective use and from a manufacturer agreed with the Engineer.

Storm Water Network pipe material for diameters up to and including 400mm should be uPVC capable of handling storm water, fit for respective use and from a manufacturer agreed with the Engineer. Storm water network with pipe diameters above 400mm should be of GRP capable of handling storm water, fit for respective use and from a manufacturer agreed with the Engineer.

General requirements for the foul and storm water works shall conform with the MoWH SDD, Standard Specification for Sewerage and Drainage Civil Engineering Works and the specific requirements of this Technical Specification.

4.1.2 Scope of Work

The works include for the supply, installation, testing and commissioning of the Water Services installation, the layouts for which are shown on the Drawings. Future connection for the secondary and tertiary irrigation system will be undertaken using saddle connections and shall be the responsibility of the tertiary irrigation system designer. However, the Scope of Works does include service connections that are detailed in the Drawings.

The Contractor shall include for all labour, materials, tools and tackle, complete with all trenching and backfill.

The Contractor shall include for the preparation for all necessary working Drawings. The Contractor shall be responsible for the correct setting out of the installation.

4.1.3 Standards



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All calculations, drawings and submissions shall be in SI (System International) units. Material items shall be to the latest BS (British Standard) or equivalent comparable internationally recognised standard of construction and quality.

4.2 MATERIALS TO BE FURNISHED BY THE CONTRACTOR All materials shall be provided by the Contractor, unless otherwise specified, including but not limited to pipes, collars, rubber rings, valves, hydrants to the approval of Civil Defence and fittings.

The materials provided by the Contractor shall include all materials for temporary works, planking and strutting, excavations, shuttering and formwork, staging and scaffolding, compliant filling materials, all materials required for repairing the internal coating of valves, etc., such as primer, coal tar enamel etc., all concrete of each required class including reinforcing steel and mesh, all surface boxes etc.

All materials supplied locally by the Contractor shall be of the best quality in their class and of the respective kinds as described in the Contract and in accordance with the Engineer's instructions and to the satisfaction of the Engineer. They shall be inspected from time to time at the site during the progress of the work.

Any materials arriving on site found unsuitable shall be rejected. The Contractor shall replace the rejected material at his own expense.

The Contractor shall, before supplying any local material, prepare and submit, at his expense, to the Engineer for review samples of materials which he proposes to use. Such samples shall be retained by the Engineer. The materials represented shall not be used in the works unless and until the samples have been accepted in writing by the Engineer.

4.3 EXECUTION

4.3.1 Pipe Materials

Table 4.1: Pipe Material Schedule

Service Pipe Dia (mm) Location Material

Foul Sewer 300 and below Land uPVC 350 and above Land GRP Foul Sewer Pressure Main 100 / 150 Land GRP 350 Land GRP 100 /150 / 350 Bridge DI Rider Sewer 150 Land uPVC Storm Water 400 and below

450 and above Land Land

uPVC GRP

Irrigation Main All Land HDPE All Bridge Epoxy lined DI Potable Water All Land HDPE All Bridge Cement lined DI



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4.3.2 Pipe Installation

Pipe installation shall be in accordance with the general pipe laying requirements of the WDD and SDD Standard Specifications and the specific requirements as follows:

- Necessary facilities including slings shall be provided for lowering and properly placing the pipe section in the trench without damage. The pipe sections shall be laid to the line and grade shown and they shall be closely jointed to form a smooth flow line. Immediately before placing each section of pipe in final position for jointing, the bedding for the pipe shall be checked for firmness and uniformity of surface.

- At all times when the work of installing pipe is not in progress, all openings into the pipe and the ends of the pipe in trenches or structures shall be kept tightly closed to prevent entrance of animals and foreign materials. The Contractor shall take all necessary precautions to prevent the pipe from floating due to water entering the trench from any source, shall assume full responsibility for any damage due to this or any other cause, and shall at his own expense restore and replace the pipe to its specified condition and grade if it is displaced. The Contractor shall maintain the inside of the pipe free from foreign materials and in a clean and sanitary condition until handover.

- All piping and fittings shall be installed true to alignment and rigidly supported. Anchorage shall be provided where required. Any damage to linings shall be repaired to the satisfaction of the Engineer before the pipe is installed. Each length of pipe shall be cleaned out before installation. All of manufacturer's recommendations shall be complied with.

- The deflection at joints shall not exceed that recommended by the pipe manufacturer. Fittings, in addition to those shown on the Drawings, shall be provided, if required, in areas where conflict exists with the existing facilities.

- When pipe cutting is acceptable to the Engineer, the cutting shall be done by abrasive saw, leaving a smooth cut at right angles to the axis of the pipe. Any damage to the lining shall be repaired to the satisfaction of the Engineer.

4.3.3 Jointing

Jointing shall conform to WDD and SDD Standard Specifications and the following specific requirements.

- Flanged joints shall be made using gaskets, bolts, bolt studs with a nut on each end, or studs with nuts where the flange is tapped. The number and size of bolts shall conform to the same ANSI Standard as the flanges.

- Bolts in flanged joints or mechanical joints shall be tightened alternately and evenly.

- Sleeve type couplings and grooved joints using split ring couplings shall be installed in accordance with the procedures recommended by their respective manufacturers.

- All pipe and appurtenances connected to equipment shall be supported in such a manner as to prevent any strain being imposed on the equipment. When



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manufacturers have indicated requirements that piping loads shall not be transmitted to their equipment, submit a certification stating that such requirements have been complied with.

4.3.4 Excavation and Backfilling

Excavation and backfilling shall conform to WDD and SDD Standard Specifications unless specified otherwise in the Technical Specifications.

4.3.5 Underground Warning Tape

The Contractor shall install specified warning tapes during backfilling work over buried pipes, cables, conduits and ducts, as required. Warning tapes shall be coloured and inscribed for identification according to the requirements below.

Table 4.2: Underground Warning Tape Requirements

Service Colour Caution

Foul Sewer Red “Caution: Sewage Pipe Below” Foul Sewer Pressure Main Red “Caution: Sewage Pressure Main Below” Irrigation Main Orange “Caution: Irrigation Pipe Below. Not for Drinking.” Storm Drain Grey “Caution: Storm Drain Below” Potable Water Main Blue “Caution: Water Main Below.” (Potable water mains

shall be protected in accordance with the requirements of the MEW, Water Distribution Directorate, Specifications of Items for Water Supply

All warning tapes shall be submitted to the Engineer for acceptance prior to delivery to site.

Warning tape shall be high quality, acid and alkali-resistant polyethylene film 300 mm wide, and with a minimum thickness of 0.10mm. The tape shall be laid in a continuous manner above each service at depth of 0.3m below ground level, and shall be continuously and indelibly marked in English and Arabic with the appropriate wording.

Tape shall be printed with 50 mm high black lettering or white lettering where the tape is black. The complete wordings shall be repeated every 2m along the tape. The colours shall be vivid, glossy and permanent with a life expectancy of 40 years.

Warning tapes shall be placed with the inscriptions facing upwards. The level of the tape relating to the top of service shall be in accordance with the requirements of the relevant services standard detail Drawings.

Warning tapes over non-metallic services shall be backed with Aluminium foil to facilitate detection.

4.4 POTABLE & IRRIGATION PIPES AND FITTINGS

4.4.1 High Density Polyethylene Pipe



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- Polyethylene pipes shall be High Density Polyethylene (HDPE) manufactured and tested in accordance with ISO 4427 (Polyethylene Pipes and Fittings for Water Supply Specification). The polyethylene pipe shall be designed to sustain a maximum working stress of 50 bar at 20°C. The wall thickness shall be based on a nominal pressure rating (PN) of 10 bar.

- Except as otherwise indicated, the current editions of the following Standards apply to the work in this section;

a. ASTM D 2447-95 - Standard Specification for Polyethylene (PE) Plastic Pipe, Schedules 40 and 80, based on Outside Diameter

b. ASTM F 714-95 - Standard Specification for Polyethylene (PE) Plastic Pipe, (SDR-PR) based on Outside Diameter

- Polyethylene pipes with outside diameter less than or equal to 12” (406 mm) shall be manufactured under ASTM D 2447-95 -Standard Specification for Polyethylene (PE) Plastic Pipe, Schedules 40 and 80, based on Outside Diameter while polyethylene pipes with outside diameter greater than 12” (406 mm) shall be manufactured under ASTM F 714-95 -Standard Specification for Polyethylene (PE) Plastic Pipe, (SDR-PR) based on Outside Diameter.

- All compound used shall be virgin plastic. Clean work material from the manufacturer’s own pipe production maybe used so long as the original was virgin material and of the same type, class and grade as required above.

- Pipes shall be manufactured from polyethylene containing only those antioxidants, UV stabilizers and pigments necessary for the manufacture of pipes and conforming to this Specification and for its end use, including weldability, when it is possible.

- When used under conditions for which they are designed, pipe materials shall not constitute toxic hazard, shall not support microbial growth and shall not give rise to unpleasant taste or odour, cloudiness and discoloration of the water.

- The pipe shall be homogeneous throughout and essentially uniform in colour, opacity, density, and other properties. The inside and outside surfaces shall be semimatte or glossy in appearance (depending on the type of plastic) and free of chalking, sticky, or tacky material. The surfaces shall be free of excessive bloom, that is, slight bloom is acceptable. The pipe walls shall be free of cracks, holes, blisters, voids, foreign inclusion, or other defects that are visible to the naked eye and that may affect the wall integrity.

4.4.2 Jointing

The jointing system for HDPE pipes and fittings shall be in accordance with the butt-fusion method and the pipe manufacturer’s recommendations subject to acceptance by the Engineer. When the pipes supplied under these Specifications are installed and joined by this method, the work shall be carried out only by well-qualified personnel who adhere strictly to prescribed working conditions, using tools and procedures recommended by the manufacturer and accepted by the Engineer.



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- Equipment - The equipment needed shall be as described in ASTM D-2657.

- General Procedure - The following procedure shall be followed when making a butt-fusion joint unless agreed otherwise with the Engineer:

a. Wipe each pipe-end clean, inside and out to remove dirt, water, grease, and other foreign material.

b. Square off the end of each pipe section to be used using a facing tool. Remove cuttings and burrs from pipe ends.

c. Check line-up of pipe-ends in fusion machine to see that pipe ends meet squarely and completely over the entire surface to be fused. Two clamps should be used on each end of pipe to be fused for sizes 100 mm and above.

d. Insert the heater plate between the aligned pipe ends. Bring and hold the pipe ends in contact with the heater plate. Maintain contact and allow pipe to heat and soften until a bead of molten plastic rolls back from the ends. This bead will be about 1.5 mm to 5.0 mm back from the end of the pipe depending on size. Soften approximately 1.5 mm on all sizes up to 75 mm; on 75 mm to 150 mm heat to 3 mm and for the above 150 mm heat to 5 mm. Softening can be judged by the appearance of the pipe end as the material softens.

e. Both surfaces of the heater plate shall be clean and the temperature maintained at 2460C-2600C (4750F to 5000F).

f. Carefully move the pipe ends away from the heater plate and remove the plate. If the softened material sticks to the heater plate, discontinue the joint. Clean heater plate, re-square pipe ends and start over.

g. Bring the heated pipe ends together with the specified pressure to form a uniform double bead about 3 mm to 5 mm wide around the entire circumference of the pipe.

h. Allow the joint to cool and solidify while maintaining the pressure for the specified time. Inspect the joint for a uniform non-porous appearance. If the joint appears faulty, cut the joint out and repeat the procedure.

4.4.3 Sampling and Testing

At least one piece or set (depending on the quantities specified by the test method) of sample/s per production batch (one production run or one production shift, whichever is shorter) shall be taken at random for testing in accordance with the methods and procedures specified in the appropriate Standard.

- ASTM D 2447-95 – Standard Specification for Polyethylene (PE) Plastic Pipe, Schedules 40 and 80, based on Outside Diameter

- ASTM F 714-95 – Standard Specification for Polyethylene (PE) Plastic Pipe, (SDR-PR) based on Outside Diameter



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The pipes shall be tested in accordance with the methods prescribed in this standard. The frequency of sampling and testing of pipes shall also follow the procedures stated in this standard.

4.4.4 Basis of Acceptance / Rejection

All samples must pass the required tests for the whole lot to be accepted. Failure of one sample would require a confirmation test on another set of two (2) samples collected at random from the same lot. The said lot shall be accepted if all confirmation samples pass the tests.

4.4.5 Ductile Iron Pipe And Fittings

The Contractor shall furnish all labour, materials, equipment and incidentals required, install, and test ductile iron pipe and fittings for the pipe networks as shown on the Drawings and as specified herein.

All ductile-iron pipe and fittings to be installed under this project shall be inspected and tested at the foundry as required by the standard Specifications to which the material is manufactured and in accordance with MEW WDD materials requirements. The Contractor shall furnish in duplicate to the Engineer sealed certificates of such tests and their results prior to the shipment of the pipe.

All ductile-iron pipes and fittings shall be from a single manufacturer and shall comply with WDD and SDD Standard Specifications.

Ductile iron pipe and fittings shall conform to BSEN 545 current at time of Tender in accordance with the requirements of the WDD and SDD Standard Specifications.

4.4.6 Thrust Restraints

- General

a. Ductile Iron pipe and fittings requiring thrust restraint shall be furnished with push-on restrained joints or mechanical joint restraints as required.

- Push-On Restrained Joints

b. Restrained joints shall be "Flex-Ring" or "Lok-Ring" restrained joints as manufactured by American Ductile Iron Pipe or equal to the satisfaction of the Engineer. Field-adaptable restraint shall be provided through the use of "Fast-Grip" or "Field Flex-Ring" as manufactured by American Ductile Iron Pipe, or bolt-less, push-on restrained devices to the satisfaction of the Engineer. When restrained joints require factory welding, the Manufacturer shall qualify all welding procedures and welders used to produce the product as per the requirements of a documented quality assurance system based on ANSI/AWS D11.2. Unless otherwise specified, gasket material shall be standard styrene butadiene copolymer (SBR). Restrained joints and restrained joint pipe shall be rated for the minimum pressure shown in Table 306.3 or the specified pressure rating of the pipe, whichever is less. The Manufacturer shall furnish test results



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showing that restrained joints in the sizes specified have been successfully tested to at least twice the specified pressure rating of the joint without leakage or failure. Tests shall be performed on pipe with nominal metal thickness less than or equal to that specified for the project. Torque-activated restrained joint devices that rely on threaded bolts or set-screws for joint restraint shall not be used.

Table 4.3: Restrained Joints Pressure Ratings

RESTRAINED JOINT PRESSURE RATINGS, (psi) & ALLOWABLE JOINT DEFLECTIONS (Limited to the pressure rating of the pipe)

JOINT SIZE FAST-GRIP FIELD FLEX-RING FLEX-RING 100mm 350 / 5o 350 / 5o 150mm 350 / 5o 350 / 5o 200mm 350 / 5o 350 / 5o 250mm 350 / 5o 350 / 5o 300mm 350 / 5o 350 / 5o 350mm 250 / 4o 350 / 4o 350 / 4o 400mm 250 / 3o 350 / 3.75o 350 / 3.75o 450mm 250 / 3o 350 / 3.75o 350 / 3.75o 500mm 250 / 3o 350 / 3. 5o 350 / 3. 5o 600mm 250 / 3o 350 / 3o 350 / 3o 900mm 150 / 2. 5o 250 / 2. 5o 250 / 2. 5o

- Mechanical Joint Restraints

c. Restrained joints shall be mechanical joint restraining glands, incorporating a number of individually actuated wedges. The assembled joint shall maintain its flexibility after burial and shall maintain its integrity by a controlled and limited expansion of each joint during the wedging action. Restraining glands shall be manufactured of ductile iron conforming to the requirements of ASTM A 536, Grade 65-45-12. Wedging mechanisms shall be manufactured of ductile iron heat treated to a hardness of 370 BHN minimum and shall be contoured fit each pipe size exactly. Dimensions of the gland shall be such that it can be used with the standardized mechanical joint bell and tee head bolts conforming to the requirements of ANSI/AWWA C111/A21.11 and ANSI/AWWA C153/A21.53 of latest revision. Twist off nuts shall be incorporated in the design of the wedge activation screws to insure proper torque during installation.

d. The mechanical joint restraining device shall have a working pressure rating of 200 psi minimum with a safety factor of at least 1.5:1 against separation when tested in the dead-end situation.

4.5 PAINTING Dry film thickness (DFT) of all painted valves and spool pieces shall be measured on delivery to site. DFT shall be the average of no less than three measurements, with no one



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measurement less than 75% of nominal average DFT. Holiday tests shall be carried out on internal and external surfaces on delivery, and also on external surfaces prior to back filling.

4.6 PIPELINE PRESSURE TESTING Hydrostatic field tests shall be conducted on the pipelines to a minimum pressure of 1.5 working pressure and in accordance with the WDD and SDD Standard Specifications.

4.7 CLEANING Clean the entire pipe by flushing with water or other means to remove all dirt, stones, pieces of wood, or other material which may have entered during the construction period. All debris shall be removed from the pipeline. The lowest segment outlet shall be flushed last to assure debris removal.

4.8 DISINFECTION Once completing distribution network and after performing all other necessary system operating tests to obtain acceptance from the Engineer for taking over of the completed system the Contractor should proceed to perform disinfection on the system through WDD approved method and the system should be disinfected in the presence of the Employer’s Representative and the Engineer for obtaining a taking over certificate.



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5 FOUL & STORM DRAINAGE PIPES AND FITTINGS

5.1 GENERAL This Part specifies the requirement for pipework, gullies, manholes, catch pits, and other items related to drainage. Related Sections and Parts are as follows:

5.1.1 References

The following standards are referred to in this Part:

- BS 497 Manhole covers, road gully grating and frames for drainage purposes

- BS 743 Materials for damp-proof courses

- BS 1142 Fibre building boards

- BS 1247 Manhole steps

- BS 2494 Elastomeric seals for joints in pipework and pipelines

- BS 4660 unplasticized polyvinyl chloride (PVC-U) pipes and plastic fittings of nominal sizes 110 and 160 for below ground gravity drainage and sewerage

- BS 6076 Tubular polythene film for use as protective sleeving for buried iron pipes and fittings

- BS 548 1 unplasticized PVC pipe and fittings for gravity sewers

- BS 59 11 Precast concrete pipes, fittings and ancillary pro ducts

- BSEN 124 Gully tops and manhole tops for vehicular and pedestrian areas

- BS 2494 Elastomeric seals for joints in pipework and pipelines

- BS 5480 Glass reinforced plastic (GRP) pipes and fittings for use for water supply or sewerage

5.2 PIPE MARKING Each pipe and pipe fitting shall be marked with the following:

- Serial number

- Class of pipe

- Nominal diameter

- Name or trademark for manufacturer

- Date of manufacture.

5.3 HANDLING AND STORAGE Each item to be provided under this Part shall be stored and handled in accordance with the recommendations of the manufacturer of the item.



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Products susceptible to ultra violet degradation shall be stored under cover and out of direct sunlight.

Pipes and fittings shall be subject to visual inspections after off-loading at the site and before installation.

5.4 QUALITY ASSURANCE Pipes, pipe fittings, manhole covers and frames and gully covers, gratings and frames shall be supplied by manufacturers acceptable to the Engineer as designated in the Technical Specifications. Production facilities shall be quality assessed in accordance with ISO 9000.

5.5 UNIPLASTICISED POLYVINYL CHLORIDE (uPVC) PIPE AND FITTINGS All uPVC pipes and fittings shall be from a manufacturer acceptable to the Engineer.

Recycled material shall not be used for manufacture uPVC products.

Seal rings for joints shall be EPDM rubber, resistant to sewerage, chemical agents etc.

Manufacturer shall provide corporate guarantee for performance of 60 years. 60 years guarantee means that if the pipe is exposed and retested after 60 years of service then it should retain at least 80% of its original properties.

With each consignment the supplier shall along with his delivery note, routine QC test reports that shall also include the batch numbers that comprises the consignment, date of production and numbers from each batch.

The traceability system of the supplies shall be such that it should be able to trace any failure at least up to the raw material sources.

Any personnel from the Employer, his representatives or the Engineer wishing to visit the supplier's yard, testing arena, storage area, etc. shall immediately be given access. If any regular/random test, raw materials invoices or QA/AC records are requested to check the continued compliance, such request shall be responded to immediately.

Pipes and fittings shall generally comply with DIN 8061/8062/8063 series unless particular deviations and/or references are made. Irrespective of the application at the site all the Push-Fit-Rubber-gasketed jointed pipes shall be pressure rated into classes 6, 10 or 16 as specified.

The following Table 5.1 specifies the minimum particular requirements/tests to be carried out at the given frequency. Where appropriate, ISO 4422 shall be followed with a factor of safety 2.5 for both specification and test method. The standards mentioned (latest at time of Tender) here are for specific compliance. Nevertheless this in no way replaces the Contractor’s and any other organization's testing regime. All the test Certificates shall be retained for at least 10 years for any inspection and auditing.

The percentage of PVC in the pipe shall not be less than 90% when tested by a loss on ignition test. The K value that is used in designing the network is generally 0.06, as per Colebrook and White Designing charts and the pipes supplied shall possess this value of friction co-efficient.



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Pipes shall be completely circular and no-ovality or bending from straightness is permitted.

If any random test fails in any property the batch from which the sample was taken shall be rejected and immediately removed from the site. In addition three (3) further samples from batches identified by the Engineer shall be tested and if any one of these three (3) further samples fails then the supplier(s) of the materials shall no longer be considered acceptable and all material from the supplier(s) shall be removed from site and the Contractor shall submit details of alternative supplier(s) all at no cost to the Employer.

Any discrepancy/contradiction among/within Specifications, Standards, Drawings, etc. immediately shall be brought to the notice of the Engineer for further clarification.

Table 5.1: – Restrained Joints Pressure Ratings (uPVC)

Test Specs. Test Method

Freq.

Remarks

Density DIN 8062 ASTM D792 D Shall be < 1.44 g/cm3 Marking DIN 8062 Visual F Contract No. Also, every

2m Short Term Hydro Test @ 20ºC DN 8061 ISO 1167 A DIN 8062 also EPDM Gasket Tests EN 681-1 EN 681-1 C EPDM only Impact at 0ºC ISO 3127 ISO 3127 B TIR<10% Joints Tightness (each size/class) ISO 4422 ISO 4422 D --- Water Absorption DIN 8061 DIN 8061 D < 4mg/cm2 Vicat Softening ISO 2057 ISO 2507 D > 79ºC Heat Reversion DIN 8061 ISO 2505 A < 5% Yield Stress & Elongation ISO 6259 ISO 6259 B Yield >45MPa and

Elongation >80% Opacity ISO 4422-2 ISO 7686 A --- H2SO4 Resistance ISO 3473 ISO 3473 D --- Outer Diameter DIN 8062 ISO 3126 A If ISO 161/1 then tolerance

ISO 3606 Wall thickness DIN 8062 ISO 3126 A If ISO 4065 then tolerance

ISO 3606 Resistance to Acetone ISO 3472 ISO 3472 A No

delamination/disintegration Loss on Ignition - ASTM D2584 B No more than 10% residue MRS-Value > 10 000 hrs test ISO 4422 ISO/TR 9080 E First one within 2 years Appearance DIN 8061 DIN 8061 A --- Freq. Legend: A-Every Shift; B-Monthly; C-Yearly; D-Once a Contract; E-5 Yearly; F-Every Pipe

Pipe classes shall be in accordance with following table:

Table 5.2: Restrained Joints Pressure Ratings

Diameter OD

(mm)

< 8m cover between Final Ground Level and Invert

> 8m cover between Final Ground Level and Invert

160 Class 10 Class 16 225 Class 10 Class 16 280 Class 10 Class 16 315 Class 10 Class 16



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5.6 GLASS REINFORCED PIPE (GRP) & FITTINGS All GRP pipes and fittings shall be from manufactures acceptable to the Engineer. The GRP pipe and fitting laminate shall consist of an inner chemical resistant layer (liner) and an outer structural layer.

All pipes shall be manufactured either by centrifugal system or by filament winding process employing a dual helix angle winding pattern, using pre-stressed continuous glass rovings.

The filament wound pipe shall be made on a straight steel mandrel with only slight taper to facilitate demoulding of the pipe from the mandrel.

Centrifugally cast GRP pipes shall be acceptable if, in addition to all requirements stipulated for GRP pipe manufactured by other process are complied, the following requirements are also met:

- Flexural modulus of the pipes shall not be taken into account.

- The maximum sand content in the structural wall of storm water drainage, foul sewerage and all pressure pipes shall not exceed the allowed limit. Sand shall not be permitted in the inner chemical resistant layer.

- If the manufacturer prefers not to use a veil tissue of ‘ECR’ or ‘C’ glass, then it shall be replaced it with only a vinyl ester resin.

No pigments or dyes may be incorporated into the laminate and no sand fillers may be present in the inner chemical resistant layer. Pipes and fittings for pressure mains shall not incorporate sand in outer structural layer. High purity silica sand may be incorporated into the structural layer of pipes and fittings for gravity flow application and diameters greater than 400mm though under no circumstances will the sand content exceed 30%. All other gravity mains shall not incorporate sand in the structural layer.

The inner chemically resistant layer (liner) shall be composed of either a vinyl ester Derakane 411-45 from Dow Chemicals or Repoxy R-802 from Showa High Polymer or exact equivalent even in raw materials used. This inner layer shall have a minimum thickness of 2mm for pipes conveying foul or effluent water and 1mm for pipes conveying storm or clean water and the inner surface shall be reinforced with 'C' glass. The resin content by weight reducing form approximately 90% at the inner surface to 65% - 75% at the outer surface of the liner.

The outer structural layer shall be composed of isophthallic resin, resistant to mineral acid of PH lower than 2.0, reinforced with 'ECR' (electro corrosion resistant) glass rovings, for pipes conveying foul or effluent water or 'E' glass rovings for pipes conveying storm or clean water as appropriate to give a final product of sufficient strength to meet the tensile and flexural requirements of the pipe. The exterior surface shall be relatively smooth with not exposed fibres or projections.

Where the Engineer has accepted use of a manufacturing process which precludes the possibility of liner pre-gelling, an acid resistant grade 'ECR' glass reinforcement shall be used for pipes conveying foul or effluent pipes, 'E' glass for pipes conveying storm or clean water.



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The results of the strain-corrosion tests carried out in accordance with ASTM-D3681 whilst the pipe is exposed to 10% sulphuric acid at a temperature of 50°C shall indicate that the pipe has lifetime of 60 years under operating conditions.

5.6.1 Testing

The following tests shall also be carried out by pipe manufacturers at their works. The results of these tests shall be made available to the Engineer on request. The Engineer shall also be allowed to witness some or all those tests.

- Works hydraulic tests:

a. Pipes and fittings for gravity application – 1 pipe in 30 to be hydraulically tested to 1.5 bars internal pressure.

b. Pipes and fittings for pressure application – All to be hydraulically tested to a rated pressure, if specified, or to three times the maximum sustained operating pressure or to 25 bars internal pressure whichever is the lesser.

c. The above tests to be in accordance with BS 5480 and a minimum duration of test to be 5 minutes.

d. Joints for gravity application – 1 joint in every 100 pipe/fitting produced shall be tested in accordance with ASTM-D3262-81.

e. Joints for pressure application – 1 joint in every 100 pipe/fitting produced shall be tested in accordance with ASTM-D3517-81

- Raw materials - All raw materials shall be tested by sampling for consistency to their Specification. No change of raw material source shall be permitted for a particular application.

- Wall thickness - Shall be measured for every pipe.

- Stiffness - Test shall be carried out to ASTM-D2412 and at a frequency of 1 pipe in 30.

- Beam Strength - Tests shall be in accordance with ASTM-D3262 for gravity pipe and ASTM-D3517 for pressure pipe and at a frequency of 1 pipe in 100 shall apply.

- Reinforcement Content - An analysis of glass reinforcement, resin and filler content of a minimum of 1 pipe in 30 shall be made. The tests shall include analysis of the inner liner by separation from the structural layers before ignition.

- Cure of pipe - A Barcol Hardness test for cure of internal and external surfaces shall be made on a minimum of 1 pipe in 30. A minimum figure of 85% of the resin supplier's recommended hardness shall be required.

5.6.2 Design Parameters to be Considered by the Contractor

The following design parameters shall be considered by the Contractor in selecting products:

- The maximum pressure attained in the pipeline inclusive of surge shall not exceed the maximum sustained working pressure rating of the pipe.



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- The surge pressure amplitude (i.e. the difference between the maximum and minimum surge pressures) shall not exceed one half of the maximum sustained working pressure of the pipe.

- The pipe shall have a minimum stiffness of 10,000 N/m for depth greater than 8m and 5000 N/m for a depth of less than 8m.

- The maximum long term diametrical deflection shall not exceed 5%.

- Wall strains shall be limited to values declared by the manufacturer on the basis of long term performance test information. Typically, these shall be a maximum of 0.5% when calculating wall strains using the formula.

e = Df. (d/D) (t/D) where, e = strain d = diametrical deflection in mm t = pipe wall thickness in mm D = pipe diameter in mm and Df is a factor primarily dependent on the ratio of pipe stiffness to soil stiffness on the bedding. The values of Df to be adopted shall be as follows:

Pipe Stiffness (N/mm2) Df

5,000 6 10,000 5 30,000 4

5.6.3 Additional requirements: GRP Pipe Data to be Submitted.

The following details of GRP pipes and fittings shall be submitted to the Engineer.

- Detailed description of manufacturing process.

- Data for each class of each diameter of pipe.

- Details of all resins to be used in the manufacture including the name, manufacturer, type and properties. Details of all curing agents, flexibilisers and other additives shall also be given.

- Details of glass fibre including type, name of manufacture and tex of rovings.

- Details of all aggregates used in the manufacture including a sieve analysis and particle gradation curve for each aggregate.

- Details of joints and rubber rings or gaskets including ring or gasket manufacturer's name, type, and reference number, rubber type and hardness, calculations to show that the stretch and compression of the ring will be within the range recommended by the manufacturer. A copy of these recommendations and fully dimensioned drawings of joints. These drawings shall show the main pipe barrel and the complete joint between two pipe ends. Dimensions of internal diameter, wall thickness, length of joint and the extent of all shaping, cut outs etc., should be indicated on the drawing together with the manufacturing tolerances on these dimension for each class of each diameter of pipe.



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- Details of all fittings including fully dimensioned drawings.

- Results of all type tests as required by the Specifications

5.6.4 Handling and Installation Specification

The pipe Manufacturer's Specification shall take account of and incorporate the requirements of the following:

- All details should be provided relating to the handling and storage of GRP pipes including:

a. pipe and rubber ring storage facilities

b. site transport

c. lifting methods

- Full details with sketches of installation procedures in open trench and such other methods of pipeline construction proposed including:

d. excavation widths and bedding depths appropriate to native soil types and bedding classes proposed.

e. procedures for determining appropriate installation parameters.

f. pipelaying and jointing techniques.

g. bedding backfill and compaction procedures for each class of bedding material.

- Details of the bedding materials required by the pipe manufacturer together with a grading curve and/or sieve analysis of each in tabular form and the degree of compaction to be achieved by the Contractor.

- Testing procedures and details, with sketches, of the deflection measurement apparatus.

- Details of in-situ joint construction involving hand lay-up butt and wrapped joints.

- Procedures for building the pipes into concrete structures, together with sketches showing short lengths, concrete surround etc.

5.6.5 Tests for GRP Pipes

- Tests include long term stiffness, deflection and creep, flexural test, hydrostatic pressure, corrosion resistance, longitudinal and hoop tensile strength and impact resistance. The external pressure resistance shall be determined in accordance with ASTM 2924.

- The results of type tests appropriate to the proposed products shall be used to determine the properties of pipes. Each type test shall have been carried out on representative samples of the pipes or fittings to be used. If alterations are proposed to the method of manufacture, pipe material or pipe design the manufacturer shall carry out all the required type tests to the satisfaction of the Engineer.



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- Quality control tests shall be carried out on raw materials (e.g., resins, aggregates, glass) as well as on laminate specimens, and shall include but not be limited to visual inspection, checking of dimension, pressure tests etc.

- No product from any source shall be incorporated into the Works without the successful completion of all type tests, including HDB, Strain Corrosion, Creep, and Impact Tests, under the direct supervision of the Contractor and the Engineer or conducted by the competent independent Authority to the satisfaction of the Engineer.

Table 5.3: Restrained Joints Pressure Ratings (GRP)

No. Test Standard. Freq. Remarks 1 Visual Inspection ASTM D 2563 /

DIN 19565(*) 100% Acceptance level-II (Table 1),

ends shall be sealed with 2 layers Vinyl Ester Resin

2 Dimensional Check ASTM D 3567 / DIN 19565(*)

100% Make a series of at least four readings, approximately equally spaced and within 5% accuracy

3 Water Absorption ASTM D 570 1% Part 1, Table 2-18 4 Barcol Hardness ASTM D 2583 100% Min. 35 and/or 90% of resin

manufacturers declared value 5 Loss on Ignition ASTM D 2584 4% Liner, structural wall and overall 6 Initial Longitudinal Unit

Tensile Strength by Strip or Beam

BS 5480, Appendix A or B / DIN 16869, Part II (*)

1% Acceptance Range – Table 2

7 Hoop Tensile Strength ASTM D 2990 / D 1599

1% For pressure pipes only

8 Joint Tightness ASTM D 4161 1% Tests shall be conducted in straight, misaligned and in shear loading conditions

9 Hydrostatic Pressure BS 5480, Appendix K

10% for gravity

100% for pressure pipelines

10 Initial Specific Stiffness and Resistance to Structural Damage Under Ring Deflection

BS 5480, Appendix H, Method B

4%

11 Impact Resistance BS 5480, Appendix J

1%

12 Creep DIN 16869 1% All types of pipes 13 External Pressure ASTM D 2924 1 / six

months

14 Strain Corrosion ASTM D 3681 Controlled at temperature of 40 °C for minimum one set of tests consisting of 18 testing specimens

15 Hydrostatic Design Basic

ASTM D 2992, Procedure B

Controlled at temperature of 40 °C for minimum one set of tests consisting of 18 testing specimens

16 Specific Ring Stiffness and Creep Factor

BS 5480, Appendix L

One set / 3 years or at the change of the raw material source

Controlled at temperature of 40 °C for minimum one set of tests



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No. Test Standard. Freq. Remarks Under Ring Deflection (Creep)

consisting of 18 testing specimens

17 Chemical Resistance (Alkaline Environment)

ASTM D 3262 Controlled at temperature of 40 °C for minimum one set of tests consisting of 18 testing specimens under pH12

- Chemical Resistance Test (Strain Corrosion)

a. Strain Corrosion tests for determining the chemical resistant properties of fiberglass pipe in a deflection condition shall be carried out in accordance with the appropriate standards.

b. The procedure, medium and acceptance criteria for testing of GRP products shall be accepted by the Engineer prior to commencement of tests.

c. Tests shall be conducted in compliance with applicable and acceptable standards and the failure strain applicable at 60 years shall be established. The value shall not be less than or equal to 1%.

- Dimensions

d. An optical scale comparator with minimum 7 magnification having reticule graduation with a 0.13 divisions shall be used for the measurements of the wall thickness and liner thickness of products.

e. A circumferential vemier wrap tape having an accuracy of +/- 0.4mm or a micrometer caliper with an accuracy of +/- 0.25% shall be used for the determination of average outer diameter (OD) of products.

f. The length shall be measured with a steel tape or gauge having graduations of 1mm or less.

g. The wall thickness, length, diameter and squareness of pipe ends shall be measured for each pipe and fitting. The dimensions shall not deviate from the tolerances specified.

- Stiffness

h. At least one pipe out of each batch of 30 pipes (or less), shall be tested to determine the initial specific stiffness.

i. In addition, each test specimen shall be deflected to amounts according to its nominal stiffness. At the lower deflection there shall be no indication of structural damage as evidenced by inter laminar separation, separation of the liner or coating (if incorporated) from the structural wall, tensile failure of the glass fiber reinforcement, fracture or buckling of the pipe wall.

j. Specimens from pipes of 10,000 N/mm2, nominal initial stiffness shall be based on:

k. Min. 7% (Liner not to crack criteria) to DN < 200mm



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l. Min. 9% (Liner not to crack criteria) to DN > 200mm

m. Min. 15% (Structural wall not to crack criteria) to all DN

n. Specimens from pipes of 5,000 N/mm2, nominal initial stiffness shall be based on:

o. Min. 9% (Liner not to crack criteria) to DN < 200mm

p. Min. 12% (Liner not to crack criteria) to DN > 200mm

q. Min. 20% (Structural wall not to crack criteria) to all DN

r. All percentages (%) deflection stated above are of the nominal diameter (DN).

- Longitudinal Tensile Strength

s. Longitudinal tensile strength of pipes shall be carried out as specified in the appropriate standard. Tests shall be carried out on:

one pipe out 100 No's produced for each diameter for each class

- Barcol Hardness

t. A minimum of one pipe for every 30 pipes manufactured shall undergo a Barcol hardness test in accordance with BS 4549: Part 1: Appendix A.

u. A minimum of one pipe of each class and diameter of pipe shall be tested,

v. The sample pipe shall also withstand a commercial acetone test on the internal portion of the laminate.

- Loss on Ignition

w. A minimum of one pipe for every 30 pipes manufactured shall be tested in accordance with EN 60 (Glass Reinforced Plastics; determination of the loss on ignition) or ASTM D 2584 "Standard Method of Test for Ignition Loss of Cured Reinforced Resins".

- Joint Tests

x. A minimum of two pipes out of 100 pipes shall be joined and tested subject to the following:

The test pressure shall be as specified under hydraulic test. An external test pressure of 1.0 bar (gauge) shall be applied to two sections of pipe assembled with a deflected joint to check the water-tightness of the joint. The deflection during the joint test shall be 1.5º for DN <600mm and 0.5º for DN >600mm.

- Visual Inspection

y. Each pipe and fitting shall be subjected to a complete visual inspection before shipment and after off loading at site.

- Burst Test on Pressure Pipelines



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z. For pressure pipes a Burst Test shall be carried out in accordance with BS 5480 to determine the initial circumferential tensile strength of the pipe.

- Failure of Tests

aa. If any random test fails in any property then the batch from which the test sample was taken shall be rejected and additionally 3 more random samples shall be tested and if any one of these 3 fails the use of any batch of the tested product shall be suspended and the Contractor shall submit evidence to the Engineer’s satisfaction supporting further use of the product or an alternative in the Works.

5.6.6 Required Pipe Data

Table 5.4: Schedule Of GRP Pipe Data To Be Provided By Contractor

SCHEDULE OF GRP PIPE DATA TO BE PROVIDED BY CONTRACTOR

PIPE DATA UNITS Manufacturing Details Name of Manufacturer Manufacturing process for pipes Joint type Manufacturing process for bends* Summary of Design Criteria Nominal internal Diameter mm Class of Pipe Minimum Depth of Cover m Maximum Depth of Cover m Maximum Working Pressure* kN/m Test Pressure kN/m Internal Vacuum Pressure* kN/m2 Pipe Wall Structure Nominal Total Wall Thickness mm Inner Liner: Thickness Resin: Type Veil: Glass Type

mm % %

Structural Wall: Resin: Type Chopped Glass: Type Hoop Glass: Type Aggregate: Type

% % % %

Minimum Initial Pipe Properties Stiffness of Composite Section kN/m' Stiffness of Structural Section kN/m' Hoop Flexural Modulus of Composite Section of given thickness GN/m' Hoop Flexural Modulus of Structural Section of given thickness GN/m2 Longitudinal Tensile Strength of Composite Section kN/m2 Hoop Tensile Strength of Composite Section* kN/m2

5.7 DUCTILE IRON PIPE AND FITTINGS See section 5.2 for Foul and Storm Water Drainage Ductile Iron Pipe and Fittings requirements.



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6 PIPE LAYING 6.1 GENERAL

Where socketed pipes are required to be laid on a granular or sand bed, or directly on a trench bottom, joint holes shall be formed in the bedding material or final excavated surface to ensure that each pipe is uniformly supported throughout the length of its barrel and to enable the joint to be made.

Pipes shall be laid on setting blocks only where a concrete bed or cradle is used.

Where pipes are required to be bedded directly on the trench bottom, the final excavated surface shall be trimmed and levelled to provide even bedding of the pipeline and shall be free from all extraneous matter that may damage the pipe, pipe coating, or sleeving.

No protective cap, disc or other appliance on the end of a pipe or fitting shall be removed permanently until the pipe or fitting which it protects is about to be jointed. Pipes and fittings, including any lining or sheathing, shall be examined for damage and the joint surfaces and components shall be cleaned immediately before laying.

Suitable measures shall be taken to prevent soil or other material from entering pipes, and to anchor each pipe to prevent flotation or other movement before the Works are complete.

Where pipeline marker tape is specified, it shall be laid between 100 mm and 300 mm above the pipe or as specified elsewhere in the Technical Specifications and Drawings.

Before any pipe is lowered into place, the bedding shall be prepared and well compacted so that each length of pipe shall have a firm and uniform bearing over the entire length of the barrel.

Pipe shall be laid in straight lines both in the horizontal and vertical planes, between manholes or the placement of pipe shall comply with following requirements

- Each pipe shall be plumbed to its correct line and directly and accurately sighted by means of a laser positioning system or boning rods and sight rails fixed to secure posts which shall be set up not more than 20 m apart.

- Alternative methods of locating and leveling pipelines may be allowed subject to the agreement of the Engineer.

Any pipe which is not in true alignment, both vertically and horizontally, or shows any undue settlement after laying, shall be taken up and relaid correctly by the Contractor.

The trench shall be kept completely dry.

In no case shall pipes be jointed before being lowered into position.

The gasket should be positioned and lubricated prior to jointing.

The pipes shall be laid and bedded in granular bedding material except where concrete bedding or protection is required. The granular material shall extend from not less than 150 millimetres beneath the pipes to 150 millimetres above the crown of the pipes or as directed by the Engineer. Subsequent filling of the pipe trench shall be carried out as detailed in this



RI4326-D905-R3-0021 of 44 18 October 2007

Section of the Technical Specifications, as shown on the Drawings or as directed by the Engineer.

GRP pipes shall, unless otherwise directed by the Engineer, be laid on a special bedding material. The space below the barrel of the pipes shall be filled with special bedding material to the full width of the trench in layers not exceeding 150mm in thickness. After pipe laying, between the pipe and the undisturbed sides of the trench up to a depth of 150 mm above the top of the pipe. The minimum thickness of the special bedding below the barrel of the pipe shall be 250 mm or as directed by the Engineer. Where a manufacturer requires greater thickness of special bedding below, around and over the pipes than those specified herein the manufacturer’s requirements shall be deemed to have been allowed for in the rates for bedding.

Where GRP pipes are built into a rigid structure; e.g., manhole or a pumping station, the first 100mm of pipe at entry to the structure shall be surrounded by an agreed flexible material. Flexible joints shall be incorporated adjacent to structures

Where short GRP pipes are detailed these shall be factory made. Cut ends shall be sealed with two layers of resin, the second layer being paraffin wax filled to ensure full cure.

Where GRP pipes are required to surrounded with concrete, all necessary precautions shall be taken to ensure that maximum allowable deflections are not exceeded.

6.2 PIPE BEDDING Bedding for pipes shall be constructed by spreading and compacting granular bedding material over the full width of the pipe trench. After the pipes have been laid, additional material shall, if required, be placed and compacted equally on each side of the pipes, and where practicable, this shall be done in sequence with the removal of the trench supports.

6.3 CONCRETE PROTECTION TO PIPES Pipes to be bedded on or cradled with concrete shall be supported on precast concrete setting blocks. The top face of each block shall be covered with two layers of compressible packing complying with BS 743.

Concrete provided as a protection to pipes shall be Grade C20, placed to the required depth in one operation.

Where pipes with flexible joints are used, concrete protection shall be interrupted over its full cross-section at each pipe joint by a shaped compressible filler of bitumen impregnated insulating board to BS 1142 or equally compressible material. The thickness of the compressible filler shall be in accordance with Table 6.1.

Table 6.1: Thickness of Compressible Filler

Nominal bore of pipe (mm) Thickness of compressible filler (mm) Less than 450 18 450 to 1200 36



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Nominal bore of pipe (mm) Thickness of compressible filler (mm) Exceeding 1200 54

Rapid hardening cement shall not be used in concrete for the protection of plastics pipe.

Plastics pipes shall be wrapped with a layer of plastic sheeting complying with a composition in accordance with Clause 3 of BS 6076 and a nominal thickness of 125 microns before being surrounded by concrete.

6.4 COMPLETETION OF PIPE SURROUND Fill material shall, where required, be placed and compacted over the full width of the trench in layers not exceeding 150 mm before compaction, to a finished thickness of 250 mm above the crown of the pipes.

6.5 BACKFILLING Backfilling shall, wherever practicable, be undertaken immediately the specified operations preceding it have been completed. Backfilling shall not, however, be commenced until the works to be covered have achieved a strength sufficient to withstand all loading imposed thereon.

Backfilling around existing structures shall be undertaken in such manner as to avoid uneven loading or damage.

Filling material to excavations shall be deposited in layers not exceeding 250mm unconsolidated thickness and compacted to 95% modified dry density.

Where the excavations have been supported and the supports are to be removed, these, where practicable, shall be withdrawn progressively as backfilling proceeds in such a manner as to minimise the danger of collapse. All voids formed behind the supports shall be carefully filled and compacted.

6.6 GULLIES AND DRAINAGE CHANNELS

6.6.1 Gullies

Gullies shall incorporate rodding eyes. Rodding eyes shall be fitted with rubber stoppers during normal operation.

All gullies shall be trapped to prevent unwanted odours escaping from the drain.

All gullies shall in corporate aluminium silt buckets.

The Contractor shall ensure that the gully outlet and the outlet pipework are compatible.

Gully covers, gratings and frames shall comply with the relevant provisions of BS 497: Part I or BS EN I24.

The class of gullies covers, gratings and frames shall be as described in the Project Specification or as shown on the Project Drawings.



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6.6.2 Pre-formed Gullies

Precast concrete gullies shall comply with the relevant provisions of BS 5911: Part 2.

Vitrified clay gullies shall comply with the relevant provisions at BS EN 295: Part I or BS 65.

Polypropylene gullies shall be of a type detailed in the Project Specification or shown on the Project Drawings and shall be obtained from a reputable manufacturer as agreed with the Engineer.

Cast iron gullies shall be of a type detailed in the Project Specification or shown on the Project Drawings and shall be obtained from a reputable manufacturer as agreed with the Engineer.

Pre-formed gullies shall be bedded and surrounded with Grade C20 concrete to the thickness described in the Contract Documentation.

Frames shall be bedded in mortar on two courses of Class B engineering brickwork or precast concrete gully cover slabs. Precast concrete gully cover slabs shall comply with the relevant provisions of BS 59 II: Part 2.

6.6.3 Manhole

The Contractor shall prepare a standard record sheet for every manhole and structure for inclusion with the as-built drawings.

Manholes shall be constructed as shown on the contract Drawings and at the locations indicated thereon or at such other locations directed by the Engineer.

The blinding concrete shall be mass concrete Grade 20SRC and shall be protected with membrane tanking systems. The necessary period for setting, as recommended by the manufacturer, shall be allowed before beginning other works to complete the construction of the manhole.

The cover slabs shall be surmounted by cast iron manhole covers and frames of the quality specified. The covers in roads and paved areas shall be accurately set on precast concrete brickwork to the level and slopes of the roads or pavements.

In the case of shallow manholes, the cover and frame may be cast directly monolithic with the reinforced concrete cover slab and projecting up by 50 mm as shown on the Contract Drawings.

The interior face of manholes and access shafts shall be prefabricated GRP liners at least 6mm thick permanent lining.

Benchings and channels shall be preformed, inverted and filled with concrete. Alternatively, the GRP lining may be applied in-situ after constructing the benching.

GRP Lining to walls shall incorporate lugs moulded onto the outside face at 500 mm centres to allow bonding to the concrete surround. The lining shall have adequate strength to withstand handling and shall not buckle or distort during pouring of the concrete surround. Internal bracing may be used during pouring to maintain circularity and verticality.



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Precast cover slabs shall incorporate a performed flat sheet of GRP on the soffit, bonded to a circular GRP tube to form the access opening. Both linings shall incorporate lugs moulded onto the surface to allow bonding to the concrete.

Joints in the lining tubes shall not be permitted.

Joints between preformed GRP benchings and lining tubes shall be made using an external sleeve 200 mm long bonded onto both units, and then bandaged using suitable resign and chopped strand mat.

IF GRP linings to benchings are to be formed in situ the surface of the wall lining tube shall be lightly abraded over a height of 150 mm from benching level. A fillet of 50 mm radius shall then be formed of vinyl ester paste at the junction of benching and wall.

Top surface of benchings shall incorporate silica sand to form a non- slip surface.

The precast cover slab shall be seated on the walls using sand/cement mortar. The joint shall be raked out 15mm deep on the inside face and pointed with an acceptable pitch extended polyurethane sealant.

The Contractor shall provide the Engineer with a 7 year unconditional guarantee against failure of all GRP linings whether caused by defective materials or workmanship. The guarantee shall be valid from the date of completion of the installation and must be delivered to the Engineer before the issue of the Final Completion Certificate.

All manholes shall be watertight on completion and where leakage is discovered the Contractor shall perform such work and provide all materials as are necessary to render such faulty work watertight. The Contractor is warned that he shall preclude rubbish and debris being deposited in the manholes during the course of construction and he shall take the necessary measures to ensure that the manhole is kept clean both during construction and after completion.

Back filling around manholes in roads shall be carried out using granular material as directed by the Engineer.

Step iron if shown on the Drawings shall comply with the relevant provisions of BS 497: Part 1 and have a minimum clear opening of 600 mm diameter if circular or 600 x 750 mm if rectangular. All covers shall have closed key ways.

6.7 CONNECTION TO GOVERNMENT MAIN

6.7.1 General Requirements

Connection to government mains shall be done at manholes. Pipe saddles and oblique junctions will not be permitted.

Where possible and practicable, connections shall be made to future connection ports in existing Government manholes. The caps on future connection ports to which connections are made shall be cleaned and delivered to the government stores on completion of the work.



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Where it is not possible or practicable to utilise future connection ports in existing manholes, connections shall be made by either breaking into existing manholes or constructing new manholes on existing mains.

If it is necessary to break into an existing manhole, the Contractor shall break into the manhole wall, insert pipework, break out the existing benching, construct benching to suit new connection and make good. If necessary, the Contractor shall relocate the access ladder and the cover slab to suit the new benching layout .

Manholes built on an existing Government mains shall be constructed in accordance with the relevant Authorities requirements or to the requirements of the technical Specifications, whichever is the more stringent, but all to the approval of the relevant Authority. On completion, such manholes shall become the property of the Government.

The Contractor shall be responsible for all over-pumping operations associated with making connections to Government mains.

6.8 THRUST BLOCKS Though standard drawings indicate typical thrust block details the Contractor should ensure the proposed thrust blocks will be capable of handling the maximum system operating pressure during the system performance period. All details of the thrust blocks shall be submitted by the Engineer by way of shop drawings prior to commencement of construction.

Ductile Iron Pipes have specific requirements for thrust blocks and these should be referred to above.

6.9 VALVES

6.9.1 General

Valves shall be capable of withstanding corrosion in the ambient conditions.

Nylon or other thermoplastic materials liable to attack shall not be used where hydrogen sulphide is likely to be present.

All valve waterways shall be coated internally with a solvent free epoxy or polyester lining of 100% solid content to be applied at the place of manufacture. The lining shall be of 250 micron nominal thickness and holiday free.

All valves will normally be witness tested at works.

Unless otherwise specified all valves and penstocks shall be anti-clockwise opening and the maximum effort required, applied at the circumference of the hand wheel to operate the valves against the maximum unbalanced head shall not exceed 55kg.

All hand wheels shall have the words "to open" and "to close" in Arabic and English with arrows indicating the direction of rotation cast on and shall be coated in plastic, nylon or other acceptable materials in order to withstand the ambient conditions.

Unless otherwise specified or agreed spindles and extension spindles shall be of stainless steel Grade 316 S16.



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Extension spindles, where required, shall be connected by suitable muff type couplings manufactured from stainless steel grade 315S16. The muff couplings shall be supplied drilled with nuts and bolts for connection to the spindles.

A clear polycarbonate tube shall be securely fitted to protect the thread of rising spindles.

The nuts shall be of gunmetal or synthetic material and mating surfaces of gates and bodies shall be of gunmetal, copper alloy or synthetic material.

All fixing brackets, bolts and nuts, washers, etc. shall be SS grade 316 S16.

Where "Operation by Tee Key" is specified the valve or penstock shall be supplied with a suitable yoke with a squared cap of standard size to receive the tee key.

The key shall be supplied at the rate of one key per two valves or two penstocks unless the valve or penstock is to be installed in an isolated location in which case one key shall be supplied for each fitting location.

Before delivery to site all working surfaces shall be thoroughly cleaned, and, if metal, protected by grease.

Packing must be sufficient to ensure complete protection of the fitting during transit and storage.

Valves under 300 mm diameter together with all hand wheels and other easily detachable items on both valves and penstocks are to be packed in timber packing cases and properly bound with steel packing bands.

All valves of 300 mm and over are to be protected with wood or plywood discs or flanges together with straw rope and hessian wrapping.

6.9.2 Check Valves

Check valves three inches (3") and above shall be double flanged single door swing type having ductile iron body and gunmetal seat to BS1400 .Pressure Rating to be PN 16 or more. All valves shall be coated with electrostatically applied (at 2250C) epoxy internally and externally to average DFT 300 microns for protection against corrosion of body components. All nut bolts to be of stainless steel grade 316/ A4-70.

Check valves of two inches (2") and smaller shall be spring type manufactured from Brass or Bronze. Inlet and outlet to be BSP female threaded. The spring shall be of stainless steel. Pressure rating shall be PN16 or more.

The face to face lengths of the valves shall be either 2 x ND + 100 mm or to an agreed international standard, the longer length to be allowed for in all cases using make up pieces where necessary to achieve the required lengths.

All valves shall be clearway, and lugs provided on screwed seats, etc., for assembly purposes shall be removed.

Sewerage valves shall, unless impracticable through size or otherwise specified shall be capable of passing 90 mm dia. solids.



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6.9.3 Gate Valves

Gate valves shall conform to the requirements of the WDD and SDD Standard Specifications.

6.9.4 Air Valves

Air valves shall conform to the requirements of the WDD and SDD Standard Specifications and the following requirements.

- Automatic double orifice air vents shall be provided at all high points on the system. Air valves and other similar items shall confirm to BS 2591. Automatic air valves shall have non-corrosive floats in chambers with clear space ensuring blockage free operation. All components for the air valve actuating mechanism including lever shall be stainless steel.

- The body and cover of the valve should be of bronze or ductile iron with phenolic primer coating. Nozzles with seals and actuating mechanism to be located in the removable upper plate connected to the valve body using stainless steel (grade 316/A4) bolts. Valves shall be coated with epoxy internally and externally to average DFT 300 microns for protection against corrosion of body components. All nut bolts to be of stainless steel grade 316/ A4-70.

- Unless higher pressure ratings are required for the pipeline, or otherwise indicated in the Contract Documentation air valves shall have a nominal pressure rating of 10 bar which shall be marked on the valve body and shall be designed for a liquid temp. of 500C and air temperature of 700C.

Air valves for pumped pressure pipelines shall be the high pressure ‘Dual’ large orifice type. The following shall be used as a guide for the general sizing of large orifice air valves:

Table 6.2: Sizing of Large Orifice Air Valves

Pipeline Bore (mm) 200 300 350 450 600 900 1000*

Air Valve size (mm) 20 25 50 80 100 150 200

Ball size (mm) 100 100 100/125 100/125 125 125/200 150/200

* For larger mains air valves may be fitted in clusters of two or more as required.

For mains 100mm diameter or less single, small orifice type standard air valves having a nominal 25mm male thread inlet and with a ball size of 100 mm shall be used.

The test pressure for different components of the air valves shall be as follows:

Body Seat Ball/Float 20 bar 10 bar 10 bar

The materials of construction for air valves shall be as follows :-

Body, Cover & Duct Cover: Cast Iron to agreed international Standard Ball/Guide: Polypropylene Seat: Nitrile Rubber Air Release Nipple: Moulded Rubber



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All Bolts: Stainless Steel, Grade 316 S16

All components shall be highly resistant to corrosion due to sewage and very high concentrations of H2S and other gases. All internal components shall be strong in design and of stainless steel grade 316 S16.

The access cover for air valves shall be in such a position that the valves could be easily removed for repair/maintenance.

The siting of the air valves shall be at locations shown on the Drawings or as directed by the Engineer on site.

6.9.5 Penstocks

Fixings shall be of the drilled anchor type and made of stainless steel.

All penstocks shall be suitable for an on/off seating head of 10m minimum but in all instances shall be less than 1.5 the maximum working head.

The size of the penstock to be used in any particular location shall be as described in the Contract Documentation and agreed with the Engineer.

The frame, doors, sealing faces and spindles of each type shall be as specified in the appropriate clauses herein.

Unless otherwise described in the Contract Documentation all penstocks shall be provided with hand wheels of adequate diameter with suitable gearing where necessary to ensure that the required operating force applied by hand does not exceed 55 kg.

Hand wheels shall have the words ‘To Open’ and ‘To Close’ in Arabic and English with arrows indicating the direction of rotation cast on them. The direction of closing shall be clockwise and a vandal / weatherproof, clear polycarbonate tube cover shall be securely fitted to the thread of rising spindles. The tube shall be clearly and permanently engraved to indicate the position of the penstock.

Spindles shall have machine cut robust trapezoidal or square form threads as necessary. They shall be of stainless steel. Extension spindle coupling shall be of the muff type and they shall be drilled and provided with a stainless steel nut and bolt for securing the spindle to the penstock spindle head which likewise be drilled to take the bolt.

All penstocks shall be of the rising type unless otherwise stated. Headstock shall be provided except in cases where the handwheels can be mounted on the penstock frames. Unless otherwise stated for penstocks of 300mm (square or circular) or more thrust tubes shall be provided. For all motorised/actuator operated penstocks thrust tubes shall be provided between the penstock frame and headstock in order to absorb the thrust in both directions of operation. Thrust tubes shall incorporate all necessary fixing brackets and spindle guide plates.

Permissible rates of leakage under specified working head shall be as follows:

- On seating installation: 5 litres per meter of slide perimeter per hour.

- Off seating installation: 30 litres per meter of slide perimeter per hour.



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The slide perimeter shall be measured as the total length of contact faces between the gate and frame in the closed position.

All materials used in the manufacture of penstocks shall conform to international standards agreed with the Engineer if not otherwise specified.

6.9.6 Stainless Steel Penstocks

The frames and doors shall be of Grade 316 S31. The design of the doors shall be such that the required working pressures can be withstood without deflection or distortion that would affect the operation of the penstocks. Any strengthening of doors by the provision of ribs and gussets shall be carried out by welding and not by bolting.

The side sealing faces may consist of simple metal to metal contact between the door and frames or by synthetic rubber seals and plastic guides as necessary to withstand the required working pressure without leakages.

Spindle shall be manufactured in stainless steel Grade 316 S31.



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End of Specification

water distribution and controls

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