102

Requirements for Air Conditioning &Ventilation

Part 1HM Surface Ships and Royal Fleet

Auxiliaries

Ministry of Defence Defence Standard 02-102 (NES 102)

Issue 2 Publication Date 8 September 2000

Incorporating NES 102 Category 2

Issue 2 Publication Date March 2000

AMENDMENTS ISSUED SINCE PUBLICATION

AMD NO DATE OFISSUE

TEXT AFFECTED SIGNATURE &DATE

Revision Note

This Issue of this Standard has been prepared to incorporate changes to text and presentation.The technical content has been updated in line with current practice.

Historical Record

Def Stan 02-102 (Part 1)/Issue 1 1 April 2000NES 102 Issue 1 August 1983

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NAVAL ENGINEERING STANDARD 102

REQUIREMENTS FOR AIR–CONDITIONING AND VENTILATION

PART 1 ISSUE 2 MARCH 2000

HM SURFACE SHIPS AND ROYAL FLEET AUXILIARIES

This Naval Engineering Standard

is authorized for use in MOD contracts

by the Defence Procurement Agency

and the Defence Logistics Organization

Published by:

Sea Technology Group,Defence Procurement Agency,STGSA,Ash 0, #95,MOD Abbey Wood,Bristol BS34 8JH

NES 102 Part 1Issue 2March 2000

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NES 102 Part 1Issue 2

March 2000

(iii)

SCOPE

1. This Naval Engineering Standard (NES) is applicable to all HM Surface Ships and Royal FleetAuxiliaries (RFA). It defines the requirements for providing ventilation, air�conditioning andequipment cooling in surface ships, the standards to which the various systems associatedwith these functions are to be designed, manufactured and installed.

2. The requirements for air�conditioning, ventilating, purging and air purification inHM Submarines are covered by NES 102 Part 2.


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March 2000

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FOREWORD

Sponsorship

1. This Naval Engineering Standard (NES) is sponsored by the Defence Logistics Organisation,Ministry of Defence (MOD).

2. The complete NES 102 comprises:

Requirements for Air-Conditioning and Ventilation

Part 1: HM Surface Ships and Royal Fleet Auxiliaries

Part 2: HM Submarines

3. Any user of this NES either within MOD or in industry may propose an amendment to it.Proposals for amendments that are not directly applicable to a particular contract are to bemade to the publishing authority identified on Page (i), and those directly applicable to aparticular contract are to be dealt with using contract procedures.

4. If it is found to be unsuitable for any particular requirement MOD is to be informed in writingof the circumstances.

5. No alteration is to be made to this NES except by the issue of an authorized amendment.

6. Unless otherwise stated, reference in this NES to approval, approved, authorized and similarterms, means by the MOD in writing.

7. Any significant amendments that may be made to this NES at a later date will be indicatedby a vertical sideline. Deletions will be indicated by 000 appearing at the end of the lineinterval.

8. This NES has been reissued because of technical update

Conditions of Release

General

9. This Naval Engineering Standard (NES) has been devised solely for the use of the MOD, andits contractors in the execution of contracts for the MOD. To the extent permitted by law, theMOD hereby excludes all liability whatsoever and howsoever arising (including but withoutlimitation, liability resulting from negligence) for any loss or damage however caused whenthe NES is used for any other purpose.

10. This document is Crown Copyright and the information herein may be subject to Crown orthird party rights. It is not to be released, reproduced or published without written permissionof the MOD

11. The Crown reserves the right to amend or modify the contents of this NES without consultingor informing any holder.

MOD Tender or Contract Process

12. This NES is the property of the Crown. Unless otherwise authorized in writing by the MODmust be returned on completion of the contract, or submission of the tender, in connectionwith which it is issued.

13. When this NES is used in connection with a MOD tender or contract, the user is to ensure thathe is in possession of the appropriate version of each document, including related documents,relevant to each particular tender or contract. Enquiries in this connection may be made tothe authority named in the tender or contract.

14. When NES are incorporated into MOD contracts, users are responsible for their correctapplication and for complying with contractual and other statutory requirements.Compliance with an NES does not of itself confer immunity from legal obligations.


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Categories of NES

15. The Category of this NES has been determined using the following criteria:

a. Category 1. If not applied may have a Critical affect on the following:

Safety of the vessel, its complement or third parties.

Operational performance of the vessel, its systems or equipment.

b. Category 2. If not applied may have a Significant affect on the following:

Safety of the vessel, its complement or third parties.

Operational performance of the vessel, its systems or equipment.

Through life costs and support.

c. Category 3. If not applied may have a Minor affect on the following:

MOD best practice and fleet commonality.

Corporate experience and knowledge.

Current support practice.

Related Documents

16. In the tender and procurement processes the related documents listed in each section andAnnex A can be obtained as follows:

a. British Standards British Standards Institution,389 Chiswick High Road,London, W4 4AL

b. Defence Standards Directorate of Standardization, Stan 1, Kentigern House, 65 Brown Street, Glasgow, G2 8EX.

c. Naval Engineering Standards CSE3a, CSE Llangennech, Llanelli, Dyfed,SA14 8YP.

d. Other documents Tender or Contract Sponsor to advise.

17. All applications to the MOD for related documents are to quote the relevant MOD Invitationto Tender or Contract number and date, together with the sponsoring Directorate and theTender or Contract Sponsor.

18. Prime Contractors are responsible for supplying their subcontractors with relevantdocumentation, including specifications, standards and drawings.

Health and Safety

Warning

19. This NES may call for the use of processes, substances and/or procedures that are injuriousto health if adequate precautions are not taken. It refers only to technical suitability and inno way absolves either the supplier or the user from statutory obligations relating to healthand safety at any stage of manufacture or use. Where attention is drawn to hazards, thosequoted may not necessarily be exhaustive.

20. This NES has been written and is to be used taking into account the policy stipulated in JSP430: MOD Ship Safety Management System Handbook.

Additional Information

21. (There is no relevant information included.)


March 2000

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CONTENTSPage No

TITLE PAGE (i). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SCOPE (iii). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

FOREWORD (v). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Sponsorship (v). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Conditions of Release (v). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Related Documents (vi). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Health and Safety (vi). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CONTENTS (vii). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 1. GENERAL INFORMATION 1.1. . . . . . . . . . . . . . . . . . . . . . . . . 1.1 Climatic Conditions 1.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2 Design Conditions 1.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.3 Ship Subdivision 1.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.4 Operational States 1.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 2. DESIGN REQUIREMENTS/CRITERIA 2.1. . . . . . . . . . . . . . . 2.1 General Requirements 2.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2 Environment Conditions 2.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . Figure 2.1 Basic Air-Conditioning System 2.2. . . . . . . . . . . . . . . . . . . . . . . . Figure 2.2 Typical Air-Conditioning Cycle 2.3. . . . . . . . . . . . . . . . . . . . . . . 2.3 Air-conditioning and Ventilation Systems 2.4. . . . . . . . . . . . . . . 2.4 Machinery Spaces 2.5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5 Smoke Clearance 2.5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.6 Chilled Water Systems 2.6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.7 Local Exhaust Ventilation Systems 2.7. . . . . . . . . . . . . . . . . . . . .

SECTION 3. DESIGN PROCEDURE 3.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1 Concept Studies 3.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2 Feasibility 3.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.3 Design Leading to Contract Definition 3.4. . . . . . . . . . . . . . . . . 3.4 Detailed Design 3.4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 4. DESIGN DATA 4.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.1 Environmental Design Conditions 4.1. . . . . . . . . . . . . . . . . . . . . 4.2 Cooling and Heating Assumptions 4.2. . . . . . . . . . . . . . . . . . . . . 4.3 Total Heat Transfer Coefficient ‘k’ 4.3. . . . . . . . . . . . . . . . . . . . 4.4 Relative Humidity 4.4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.5 Air Distribution Systems 4.4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.5.1 Design Margin 4.4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.5.2 Air Velocities 4.4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.5.3 Fresh/Filtered Air Requirements 4.5. . . . . . . . . . . . . . . . . . . . . . 4.5.4 Standard NBC Filters 4.6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


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4.6 Pressurization 4.6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.6.1 Citadel and Zones 4.6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.6.2 Machinery Spaces 4.6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.7 Heating Systems 4.6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.8 Chilled Water Systems 4.7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.8.1 Design Margins 4.7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.9 Chilled Water Temperatures 4.7. . . . . . . . . . . . . . . . . . . . . . . . . . 4.10 Velocities and Pipe Size 4.8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 5. AIR DISTRIBUTION SYSTEMS 5.1. . . . . . . . . . . . . . . . . . . . . . 5.1 Design Objective 5.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.2 General Requirements 5.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.3 Air-conditioning Arrangements 5.2. . . . . . . . . . . . . . . . . . . . . . . 5.4 Central ATU 5.3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.5 Compartment ATU 5.3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.6 ATU Controls 5.4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.7 Special Requirements 5.4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.7.1 Operational Spaces 5.4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.7.2 Accommodation and Recreation Spaces 5.4. . . . . . . . . . . . . . . . 5.8 Medical Spaces 5.5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.8.1 Sick Bays 5.5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.9 Configuration No 1 (Full fresh air cooling) 5.6. . . . . . . . . . . . . . 5.10 Configuration No 2 (Semi-recirculation) 5.6. . . . . . . . . . . . . . . . 5.10.1 Dental Surgery 5.7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.11 Bathrooms and WC 5.7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.11.1 General Requirements 5.7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.11.2 WC and Urinals 5.8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.11.3 Bathrooms 5.9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.12 Galleys and Associated Spaces 5.10. . . . . . . . . . . . . . . . . . . . . . . . 5.12.1 Galley, Servery and Scullery 5.10. . . . . . . . . . . . . . . . . . . . . . . . . . 5.12.2 Pantries and Pantry/Serveries 5.11. . . . . . . . . . . . . . . . . . . . . . . . 5.12.3 Miscellaneous 5.11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.13 Laundries and Associated Spaces 5.12. . . . . . . . . . . . . . . . . . . . . . 5.14 Drying Rooms 5.12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.15 Workshops 5.13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.16 Sewage Treatment Spaces 5.14. . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.17 Storerooms 5.14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.18 Conversion Machinery Rooms 5.14. . . . . . . . . . . . . . . . . . . . . . . . 5.19 Magazines 5.15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.20 Compartments Containing Dangerous or Noxious Gases 5.17. . 5.20.1 General Requirements 5.17. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.21 Refrigeration Machinery Compartments, Refrigeration

Machinery and Bottle Stowages for Heavier than Air Gases 5.185.22 Battery Charging Rooms and Spaces Containing

Battery Charging Facilities 5.18. . . . . . . . . . . . . . . . . . . . . . . . . . . 5.23 Paint Rooms, Paint Stores and Flammable Stores 5.19. . . . . . . .


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5.24 Hydrogen and Acetylene Storage Compartments 5.19. . . . . . . . . 5.25 Compartments Containing Petroleum, Oils, Lubricants, etc. 5.205.26 HP Air Compressors 5.21. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.27 Incinerator Compartments 5.21. . . . . . . . . . . . . . . . . . . . . . . . . . . 5.28 Hangars 5.21. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.29 Vehicle Decks 5.22. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.30 Electrical Switchboard Rooms 5.23. . . . . . . . . . . . . . . . . . . . . . . . 5.31 Emergency Generator Compartment 5.23. . . . . . . . . . . . . . . . . . 5.32 Steering Gear (Secondary Steering Position) 5.23. . . . . . . . . . . . 5.33 Dry Provision Room 5.23. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.34 Air Balance Diagrams 5.23. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 6. COOLING SYSTEMS 6.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.1 General 6.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2 Statement of Style 6.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.3 Design Principles 6.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Figure 6.1 Combined Essential and Non EssentialServices

Chilled Water System 6.3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Figure 6.2 Discrete Essential Services Chilled Water System 6.4. . . . . . . . 6.4 System Arrangement and Components 6.5. . . . . . . . . . . . . . . . . 6.5 CW/Air Heat Exchangers (Coolers) 6.6. . . . . . . . . . . . . . . . . . . . 6.6 Materials 6.7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.7 Cleanliness 6.7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.8 Water Quality 6.8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.9 Compartment Cooling 6.9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.10 Air Treatment Units 6.9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.11 CW Unit Coolers 6.9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.12 Free Standing Air-conditioning Units 6.10. . . . . . . . . . . . . . . . . . 6.13 Equipment Cooling 6.10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.14 Demarcation 6.11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.15 Dehumidifiers and Condensation Control 6.11. . . . . . . . . . . . . . . 6.16 Insulation 6.11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.17 System Reliability 6.11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 7. HEATING SYSTEMS 7.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.1 General Requirements 7.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.2 Air-conditioned Compartments 7.1. . . . . . . . . . . . . . . . . . . . . . . 7.3 Hazardous Compartments Within the NBC Citadel 7.2. . . . . . 7.4 Fresh Air 7.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.5 Compartments Outside the NBC Citadel

(Ex Machinery Spaces) 7.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.6 Classification of Heaters 7.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.6.1 Supplementary/Boost Heaters 7.3. . . . . . . . . . . . . . . . . . . . . . . . . 7.6.2 Reheaters 7.3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.7 Heater Controls 7.3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.7.1 Positioning of Sensors 7.3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


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7.8 Electric Heater Controls 7.4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.9 Hot Water Heater Controls 7.4. . . . . . . . . . . . . . . . . . . . . . . . . . . 7.10 Trunk Mounted Heaters 7.5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.10.1 Electric Heaters 7.5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.10.2 Hot Water Heaters 7.5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.11 Space Heating 7.5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.11.1 Types of Space Heaters 7.6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.12 Hot Water Systems 7.6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.13 Heater Markings 7.7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.14 Humidifiers 7.7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 8. MACHINERY SPACES 8.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.1 System Design 8.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.1.1 Cruise State/Open Ship Condition 8.1. . . . . . . . . . . . . . . . . . . . . 8.1.2 Action State/Closed Down Condition 8.1. . . . . . . . . . . . . . . . . . . 8.2 Cooling 8.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.3 Pressurization 8.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.4 Air Systems 8.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.5 General 8.3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.6 Heating 8.3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.7 Machinery Space Ventilation Trials 8.4. . . . . . . . . . . . . . . . . . . .

SECTION 9. NBCD & FIRE FIGHTING ARRANGEMENTS 9.1. . . . . . . . . 9.1 NBCD Subdivision (See NES 118) 9.1. . . . . . . . . . . . . . . . . . . . . 9.2 Fire Fighting Subdivision (See NES 119) 9.1. . . . . . . . . . . . . . . . 9.3 Citadel Pressurization 9.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.4 Intake of Ambient Air 9.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.4.1 Calculated Uncontrolled Leakages 9.2. . . . . . . . . . . . . . . . . . . . . 9.4.2 Known Controlled Leakages 9.3. . . . . . . . . . . . . . . . . . . . . . . . . . 9.4.3 Control Of CO2 9.3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.5 Air Filtration Units and NBC Filters 9.3. . . . . . . . . . . . . . . . . . . 9.5.1 Centralised AFU 9.4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.5.2 Specialised AFU 9.5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.6 Purging 9.5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.7 Air Locks (Citadel Exits) 9.5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.8 Cleansing Station (Contamination Control Area) 9.6. . . . . . . . 9.9 Fire Fighting and Fire Precautions 9.6. . . . . . . . . . . . . . . . . . . . 9.10 Smoke Clearance/Containment - Policy (Surface Ships) 9.7. . . 9.11 Crash Stopping of Fans 9.9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.12 High Risk Areas 9.10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.12.1 Galleys (Also See Section 5) 9.10. . . . . . . . . . . . . . . . . . . . . . . . . . . 9.13 Highly Flammable Stores and Explosive Gases 9.11. . . . . . . . . .


March 2000

(xi)

Page No

9.14 Fire Flaps 9.11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Figure 9.1 Typical Fire Flap 9.12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Figure 9.2 Typical Flameproof Gauze 9.13. . . . . . . . . . . . . . . . . . . . . . . . . . . 9.15 NBCD Ventilation Board 9.14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.16 Fire Precautions in Royal Fleet Auxiliary Vessels 9.14. . . . . . . . .

SECTION 10. FANS 10.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.1 Fan Selection 10.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.2 Materials 10.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.3 Construction 10.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Figure 10.1 Application of Constant Orifice Line to

Design Margins 10.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.4 Motors 10.3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.5 Availability, Reliability and Maintainability (ARM) 10.3. . . . . . 10.6 Noise 10.3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.7 Shock 10.3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.8 Vibration (Self Generated) 10.3. . . . . . . . . . . . . . . . . . . . . . . . . . . 10.9 Vibration (Externally Generated) 10.3. . . . . . . . . . . . . . . . . . . . . . 10.10 Fan Testing 10.3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.11 Mounting and Siting of Fans 10.4. . . . . . . . . . . . . . . . . . . . . . . . . . 10.12 Special Fans 10.5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.13 Fan Markings 10.5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 11. TRUNKING AND FITTING 11.1. . . . . . . . . . . . . . . . . . . . . . . . . . 11.1 General 11.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.2 Non-Watertight, Non-Gastight Trunks 11.1. . . . . . . . . . . . . . . . . 11.3 Textile Ventilation Trunking 11.2. . . . . . . . . . . . . . . . . . . . . . . . . . 11.3.1 Advantages 11.3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.3.2 Disadvantages 11.4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.4 Gastight and Structural Trunks and Trunks

Subjected to Rough Usage or High Fire Risk Including Smoke Removal Systems 11.4. . . . . . . . . . . . . . . . . . . .

11.5 Watertight Trunks 11.5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.5.1 Trunk Installation. 11.5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.6 Vulnerability 11.6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Figure 11.1 Typical Hanger Supports 11.7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.7 Trunking - Associated Fittings 11.8. . . . . . . . . . . . . . . . . . . . . . . . 11.8 Weather Terminals 11.8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.9 Supply Outlets 11.8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.10 Exhaust/Recirculation Intakes 11.9. . . . . . . . . . . . . . . . . . . . . . . . 11.11 Miscellaneous Fittings 11.9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.12 Insulation 11.10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Figure 11.2 Typical Hose Conection for Ventilation Trunks 11.11. . . . . . . . . .

SECTION 12. FILTRATION 12.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.1 General 12.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.2 Dust Filters 12.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


(xii)

Page No

Figure 12.1 Typical Dust Filter Mounted in a Trunk 12.3. . . . . . . . . . . . . . . . Figure 12.2 Typical Dust Filter for Openings in Exhaust

and Recirculation Trunks 12.4. . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.3 Odour Filters 12.5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.4 Tobacco Smoke Filters 12.5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.5 Grease Filters 12.5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Figure 12.3 Typical Tobacco Smoke Filter 12.6. . . . . . . . . . . . . . . . . . . . . . . . . 12.6 Fresh Water Filters 12.7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.7 Standard NBC Filters 12.7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 13. VENTILATION NOISE 13.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.1 General 13.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.2 Siting and Mounting of Fans 13.1. . . . . . . . . . . . . . . . . . . . . . . . . . 13.3 Trunking and Fittings 13.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.4 System Sound Analysis 13.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.5 Tests and Trials 13.3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 14. DESIGN FOR MAINTENANCE ANDSHIP HUSBANDRY 14.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

14.1 General 14.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.2 Fittings 14.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.3 Drainage 14.3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.4 Filters 14.3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.5 Water Systems 14.3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 15. INSPECTIONS, TESTS AND TRIALS 15.1. . . . . . . . . . . . . . . . . 15.1 General Comments 15.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.2 Factory Testing 15.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.2.1 Type Tests 15.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.3 Production Tests 15.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.4 Progress Inspections 15.3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.5 NBC Filtration, Inspection and Testing 15.3. . . . . . . . . . . . . . . . . 15.6 Final Inspection 15.3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.7 Testing and Balancing 15.3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.7.1 Air Systems 15.3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.8 Air Test Reports 15.4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.9 Water Systems 15.5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.10 Zonal Pressures Tests 15.7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.11 Habitability Trials 15.7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.12 Performance Trials 15.8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15.13 Airborne Noise Trials/Surveys 15.9. . . . . . . . . . . . . . . . . . . . . . . . 15.14 Instruments 15.10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ANNEX A. RELATED DOCUMENTS A.1. . . . . . . . . . . . . . . . . . . . . . . . . . .

ANNEX B. ABBREVIATIONS AND DEFINITIONS B.1. . . . . . . . . . . . . . .

ALPHABETICAL INDEX INDEX 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


March 2000

1.1

1. GENERAL INFORMATIONRelated Documents: NES 809 Part 1; see also Annex A.

1.1 Climatic Conditions

a. For design purposes hot weather and cold weather climates throughout theworld are each divided into the following conditions, viz:

(1) Hot Weather

(a) Tropical;

(b) Temperate Summer.

(2) Cold Weather

(a) Temperate Winter;

(b) Subarctic;

(c) Arctic.

1.2 Design Conditions

a. The limiting climatic conditions to be applied to any ship design will be specifiedin the Staff Requirements (Sea) (SR(S)) for that particular class of vessel andthus, in consequence of this NES, the internal ship conditions will also bedefined.

b. The SR(S) will also indicate where the actual design may, if at all, deviate fromthe standards and policies herein and, where appropriate, it will specify themodified standards that are to be achieved.

c. Unless specifically modified by the SR(S) it is essential that all the marginsstated in this NES are applied fully throughout the design. Initial allowancesconsumed by growth during the design stages need to be compensated for, toensure sufficient margins are present in the final design to allow for through lifegrowth and degradation of the various systems. The chilled water margins arealso required as air�conditioning machinery cannot be run under overloadconditions. If an attempt is made to do so the plant may trip out, resulting in asignificant reduction in the ship's operational efficiency. Allowances for erosionof growth margins will be discussed and identified at the outset of the designcalculations.

d. HM Surface ships that are to be commercially registered, e.g. Royal FleetAuxiliaries (RFA) are, where possible, to comply with Department of theEnvironment, Transport and the Regions (DETR) regulations that governfire�fighting and safety aspects. Where DETR and MOD standards are atvariance and both sets of regulations can be accommodated then the morestringent are to be applied. As it is imperative that Nuclear Biological andChemical Defence (NBCD) integrity and the operational efficiency are notjeopardised in any circumstances any DETR rules or regulations which placethe vessel at risk shall not be applied and the relevant exception to or exemptionfrom these rules should be sought from the regulatory body and entered in thecommercial registration documents. Full compliance with DETR regulationswill be impossible as they have no category suitable for HM Surface Ships andwould normally register the vessel in the closest appropriate commercialclassification. In these circumstances discussions should take place at theoutset of the design where differences or conflicts will be clearly identified andreconciled by all concerned parties.


1.2

e. In all surface ship designs, unless stated otherwise in the SR(S), it is importantto achieve a reduced Radar Cross Section (RCS). The recommendations ofNES 809 Part 1 are to be addressed in the design of all external features, and inparticular the creation of orthogonal dihedrals and trihedrals with co�sitedfeatures is to be avoided.

1.3 Ship Subdivision

a. For each new class of surface ship the MOD will produce a ship subdivisionpolicy paper in the early stages of, or prior to, Feasibility Design that willcomprehensively state the rules governing the subdivision of that particularclass of vessel.

b. Surface ships can be divided as:

(1) Watertight decks and bulkheads;

(2) NBCD citadels and sub�citadels;

(3) Autonomous fire/smoke zones and ventilation sub�zones within theautonomous zones.

c. The design of the ventilation and air�conditioning arrangements are to becompatible with each of these subdivisions and the ducted systems are to beautonomous within individual fire zones. In the action state when allsubdivision boundaries are secured the free flow of recirculated air fromcompartment back to fan is not to be obstructed.

1.4 Operational States

a. Two operational states have to be catered for, viz:

(1) Cruise state or `open ship' condition;

(2) Action state or `closed down' condition.

b. Within the NBCD citadel, the change from cruise to action state is to be effectedby implementing air lock, cleansing station and zonal disciplines andredirecting all incoming fresh air through NBCD filters. Ventilation andair�conditioning systems are not to be reconfigured to enable this to beachieved.

c. For those compartments outside the NBCD citadel and classed as contaminatedif used, every effort is to be made for these spaces to be supplied with air fromthe citadel with natural or fan exhaust to atmosphere. Only when these spacesentail excessive amounts of conditioned air should mechanical fan supply andexhaust systems be considered. In the machinery spaces, it is to be achieved byreconfiguring the ventilation systems into recirculation systems, closingexternal openings, supplying chilled water to machinery space coolers andinitiating dedicated filtration units.

d. Once `closed down' it is to be possible to maintain that condition indefinitelywithout discomfort to personnel or loss of operational efficiency, unless theSR(S) for the vessel stipulates a specific time scale.


March 2000

2.1

2. DESIGN REQUIREMENTS/CRITERIARelated Documents: Health and Safety at Work Act, COSHH Regulations; see also

Annex A.

2.1 General Requirements

a. This section deals with the requirements governing the overall design ofventilation and air�conditioning arrangements that are to be fitted in RoyalNavy (RN) vessels. It defines the current policy that is to be applied anddescribes the style of various associated systems. It is the Designersresponsibility to incorporate these requirements.

b. Air�conditioning, that is the control of temperature, humidity, air purity and airmovement within a space or group of spaces, is a prime requirement in all RNvessels. It is an essential element in ensuring that the ship's staff continue tooperate at high levels of effectiveness and efficiency for long periods and theenvironment for weapons and other essential equipments is, and alwaysremains, satisfactory for reliable operation. This environmental control has tobe achieved throughout the full spectrum of ambient conditions for which theship is to be designed.

c. All compartments within a ship are to be classified by the designer as eitheressential or non�essential to the operational efficiency of the vessel and theseclassifications made known in the air�conditioning design.

d. For essential compartments the air�conditioning is to be based upon the `GroupSystem' where a mixture of fresh and recirculated air is delivered to an AirTreatment Unit (ATU) where it is filtered, cooled or heated, and distributed to aselected group of essential compartments (A `group' can be one or severalcompartments). In certain circumstances the cooled air may need to bereheated locally before being delivered to particular spaces to obtain thenecessary humidity control, but the use of this technique is to be kept to aminimum (See Figures 2.1 and 2.2).

e. For non�essential compartments the air�conditioning is to be based either uponthe `Group System' as described above, except that the relevant ATU is to onlysupply non�essential spaces, or, if more appropriate, on the use of Unit Coolers.

2.2 Environment Conditions

a. The design of the air�conditioning systems is to cater for the extreme ambienttemperatures stated in the SR(S) and the corresponding internal temperaturesgiven in Section 4. The final design of the installed systems is to includesufficient flexibility and controllability to allow comfortable internalenvironments to be selected and maintained throughout the full range ofconditions bounded by these extremes. This flexibility is especially importantin spaces where the internal conditions can vary significantly and speedily dueto movement of personnel or change of equipment status and should beachieved by the use of sensors situated in appropriate locations.


2.2

RETURN

A

SUPPLY TRUNK

THERMOSTAT

BOUNDARY GAINS - (SH)EQUIPMENT (SH+LH, IF ANYPERSONNEL (SH+LH)

HOT MACHINERY SPACE ETC.

C

RECIRCULATED AIR ROUTE

(MAY BE TRUNKED)

EVAPORATOR

CONDENSER

COMPRESSOR

C.W. PUMP

REFRIGERANT CIRCUIT

HEAT EXCHANGER

CHILLED WATER PLANT

FRESH FILTEREDAIR DIRECT FROMAFU SH+LH

ELECTRIC PRE-HEATERCHILLED WATER SYSTEM

ELECTRICRE-HEATER

CONNECTION BOX

AIR TREATMENT UNIT

MOISTURE ELIMINATOR

FILTER

B

BYPASS

FAN

A1

SURPLUS AIR DISCHARGED

OVERBOARD VIA HAZARDOUS

COMPARTMENT EXHAUST

SOLAR RADIATION

FLOW

NOTE A, A1, B, C and D REFER TOPOINTS SHOWN IN FIGURE 2.2NOTESH - Sensible HeatLH - Latent HeatAFU - Air Filtration Unit

CONDENSER COOLING WATER

D

Figure 2.1 – Basic Air-Conditioning System


March 2000

2.3

C

5

10

15

20

25

040302010

RELATIVE HUMIDITY

50

70

60

90

100%

90%

DRY BULB TEMPERATURE deg C

MO

IST

UR

E C

ON

TE

NT

g/Kg

12.5

10

15

17.5

22.5

25

27.5

20

D

A

B

A1

Air-ConditioningCYCLE

80

NOTE

For information on

A, A1, B, C and D

See Figure 2.1

Figure 2.2 – Typical Air-Conditioning Cycle


2.4

2.3 Air-conditioning and Ventilation Systems

a. In all ships, where required, the complete air�conditioning and ventilationdesign for compartments and spaces necessary for the functionality of thevessel in a `closed down' ship, is to be based upon the Total Atmospheric ControlSystem (TACS) concept which has been developed to achieve the minimumpracticable change�over time from `open ship' to `closed ship' condition and toenable continuous operations to be conducted in a Nuclear, Bacteriological andChemical Warfare (NBCW) threat situation. This concept requires all fresh airentering the NBCD citadel to be directed through NBC filtration units when inthe closed down condition but in the `open ship' condition these filters are to beby�passed. Compartments not necessary for the functionality of the vesselduring NBC transits should not ideally be located within the citadel but due tothe logistics of the ship they may well be and in these instances would beair�conditioned or ventilated as required. In such cases theair�conditioning/ventilation is normally to be by independent systems takingtheir required fresh air quantities from weather (not via Air Filtration Units �AFU) and they would be secured in a `closed down' situation, however inisolated cases these spaces can be served by an adjacent TACS air�conditioningsystem.

b. All compartments and spaces within the citadel are to be air�conditioned orventilated as above with the exception of those compartments classed ashazardous, i.e. compartments within the citadel which contain materials thatmay generate dangerous or toxic fumes and gases and those where such fumesand gases are produced by processes and functions carried out in thecompartment. These spaces are to be air�conditioned/ventilated to conditionsspecified in Section 5 Clause 5.20.

c. Special attention is to be paid to those compartments within the citadel that area source of unpleasant smells or noxious gases, e.g. bathrooms, WC, laundries,galleys, etc. In these types of compartment sufficient air is to be circulated toensure that odours are removed via a recirculation system employing odourfilters. For specific requirements for these compartments See Section 5.

d. The design of the air systems is to take account of and be compatible with theship�subdivision policy for each particular ship design. The air systems are tobe completely autonomous within the fire/smoke zones, and under nocircumstances is ducting to breach zone boundaries. It is essential that airbalance diagrams for each fire zone are prepared and maintained throughoutthe design to ensure that differential pressures across zonal boundaries aremaintained within the limits specified in Section 9.


March 2000

2.5

e. In both the `closed down' and òpen ship' conditions the fresh air intake into thecitadel is to be via the AFU fans (See Figure 2.1). The fresh air quantity is to besufficient to compensate for known controlled losses and calculateduncontrolled leakages, whilst maintaining an acceptable citadel over pressureand providing oxygen to revitalise compartment air by ensuring that CO2

content levels are kept below the maximum permissible levels. The fresh airrequired for oxygen replenishment is to be trunked direct to individual ATUwhere it is treated and distributed as necessary. The remaining fresh air is to beused to provide an over pressure in essential compartments (See Section 9) or isto be trunked from the AFU fan directly to or in the vicinity of anycompartment, Air Lock or Cleansing Station deemed necessary for maintainingthe integrity of the citadel.

2.4 Machinery Spaces

a. Machinery spaces are to be considered as outside of the NBCD citadel and in theòpen' condition are to be ventilated by mechanical supply and mechanicalexhaust systems. The flow of air is to be such that in specified summerconditions the compartment temperature will be maintained within statedlimits when all normally running equipments are operating. In cold weatherconditions the air flow is to be capable of being significantly reduced andsufficient electric heating provided to maintain temperatures which facilitatethe ease of starting up of machinery (normally 10°C) in the `dead ship'condition.

b. The system design is to provide, where required, for the reconfiguration of theventilation systems so that, in the `closed down' condition it will be possible torecirculate the compartment air through chilled water coolers and isolate themachinery spaces from the external ambient air. In this state a positivepressure (normally 3 millibars above ambient air pressure) is to be created andmaintained in the machinery spaces by introducing a quantity of fresh airthrough dedicated NBC filtration units. These filtration units are to benon�operational in the òpen ship' condition and the quantity of fresh airrequired is to be calculated by the summation of any known controlled lossesand the calculated uncontrolled leakages based on a loss of 0.5�air changes perhour on the gross volume of the machinery spaces inclusive of casings if open tothe machinery space.

c. The chilled water coolers in machinery spaces are to be operational in the`closed down' state and capable of being supplied from a standby non�essentialchilled water plant. Sufficient heat is to be extracted to allow the ship to be fullyoperational for the total `closed down' period and at the extreme ambienttemperatures specified in the SR(S), without these spaces becomingcontaminated. Machinery space `closed down' cooling requirements are to betaken into account when allocating the number and capacity of theair�conditioning chilled water refrigeration plants.

2.5 Smoke Clearance

a. Where a ship design includes damage fire and smoke zones, a dedicated trunkedsmoke clearance system is to be provided in each zone. These systems are to bearranged such that, within each zone, individual decks may be cleared of smokeand allow sufficient replacement air, without other unaffected decks beingcontaminated.

b. Dedicated smoke clearance systems are not required in machinery spaces whichcontain exhaust fans as these fans will be utilised for smoke clearance.


2.6

c. To prevent the migration of smoke into compartments essential to theoperational efficiency of the vessel in a fire situation, such compartments are tobe capable of being maintained at a positive pressure relative to thesurrounding passageways and lobbies.

2.6 Chilled Water Systems

a. Chilled Water (CW) systems are to provide the means for transferring heat fromthe heat exchangers, situated throughout the vessel, to Chilled Water Plants(CWP) and hence overboard via condenser cooling water.

b. Two categories of CW systems are to be included in any ship design, namely:

(1) Essential systems supplying essential heat exchangers that cool essentialcompartments and equipments. These systems are to be constrainedwithin NBCD/smoke zones and several of this type will be included ineach ship design;

(2) Non�essential systems supplying non�essential ATU and unit coolers thatcool non�essential spaces. This will be a ship wide system and each shipwill only contain one of this type.

c. Connections are to be provided between the non�essential system and eachessential system to enable the essential heat exchangers to be continuouslysupplied, when necessary, at the expense of the non�essential.

d. Adequate margins are to be applied to allow for through life growth and systemdegradation when selecting CWP and calculating pipe sizes.

e. The non�essential system is to be provided with a standby CWP so that allsystems will be able to operate continuously during periods of routinemaintenance or single plant breakdown. The standby CWP is not to beconsidered as a growth margin.

f. In any ship design the preferred arrangement is for all essential systems to beserved by identical CWP, a single plant supplying each system, and for all CWPserving the non�essential system to be identical.

g. The non�essential CWP are to be capable of cooling the machinery spaces in the`closed down' condition.

h. Rapid refill arrangements as well as normal topping�up facilities are to beprovided.

i. The design of the system and its associated equipment is to ensure that theRelative Humidity (RH) levels in individual compartments are maintainedbetween specific upper and lower limits but in exceptional circumstances, indifficult spaces, the use of approved humidifiers and dehumidifiers isacceptable.

j. In particular compartments where heavy condensation is liable to occur specialattention is to be given during the design stage to removing moisture from thecirculating air and to the use of thermal insulation to eliminate potentialproblems.


March 2000

2.7

2.7 Local Exhaust Ventilation Systems

a. Those systems defined under the Health and Safety at Work Act (HSWA),Control of Substances Hazardous to Health (COSHH) Regulations 1992 asLocal Exhaust Ventilation (LEV) Systems are to be provided, these are toinclude fixed monitoring instrumentation to allow for through life ventilationsystem flow monitoring.

b. Each designated LEV system is to have:

(1) The test point(s) marked;

(2) The required test date annotated on a plate and fixed adjacent to the testpoint;

(3) The test date plate to be permanently fixed to the trunking.


2.8


March 2000

3.1

3. DESIGN PROCEDURE

Related Documents: BS 1553 and NES 707 Parts 1 & 2; see also Annex A.

a. The design of the air�conditioning and ventilation systems is to follow andreflect the total ship design. When considering the various types of studiesundertaken it is to be understood that a ship design is a dynamic entity wheredecisions taken in one area, will often have repercussions in many other areasand air�conditioning and ventilation estimates, calculations, drawings, etc.,will need to be continually re�assessed and updated.

b. Within the field of air�conditioning and ventilation the total design process canbe divided as follows:

(1) Concept studies;

(2) Feasibility studies;

(3) Design leading to Contract Definition;

(4) Detailed design.

3.1 Concept Studies

a. These are studies to formulate new design philosophy, policies and criteria andto assess the impact of any proposed changes in future ship design. They areusually undertaken by the MOD with assistance from selected contractors, andare not necessarily associated with a particular ship design.

3.2 Feasibility

a. These are studies to combine the existing philosophy, policies and criteria with adeveloping ship design, for a specific role, and are normally carried out by ashipbuilder and his prime contractor, with assistance from MOD sponsors.

b. For feasibility studies to commence, the following information is required:

(1) Design conditions;

(2) Ship subdivision policy;

(3) Compartment details (size, manning, function, wild heat, etc.);

(4) Weapons fit and direct cooling loads.

c. This information is to be available from MOD sources when the SR(S) isapproved. When this is not the case the best possible estimates and assessmentsare to be made to allow the design of the air�conditioning and ventilationsystems to be progressed as soon as possible and updated when absolute detailsare obtained by the shipbuilder.

d. During this stage of the design the following information is to be submitted tothe MOD for records and, where necessary, comments:

(1) Design philosophy table giving details of Heating Ventilation andAir�Conditioning (HVAC) requirements for all compartments on thevessel. This table should include the compartment name, location,specified summer and winter conditions to be maintained, exhaustrequirements, noise target and manning levels, equipment wild heatemissions and any additional remarks pertinent to the design of theHVAC system;


3.2

(2) Statements of Technical Requirements (STR) for fans, heaters, coolers,etc., and programmes for testing new equipments and fittings thatrequired àpproval to fit';

(3) Classification of compartments as essential, non�essential andhazardous, and identification of those outside citadel boundaries;

(4) Calculations of heat gains and losses for every compartment, workshopand store, etc.;

(5) Grouping of compartments to show the number of essential andnon�essential heat exchangers/ATU, the number of hazardous systemsand the number of ventilation systems required in each NBCD/fire zone;

(6) Selection of type, size and numbers of CWP for essential andnon�essential CW systems;

(7) Calculations of air quantities and CW flows required for all systems;

(8) Size, type and numbers of fans, air/water and water/water heatexchangers, heaters, humidifiers and other equipments;

(9) Fresh air requirements in individual zones, machinery spaces and thenumber of AFU required;

(10) Identification of compartments to be pressurized by a direct supply offresh air to prevent infiltration of smoke;

(11) Identification of ventilation and smoke clearance systems;

(12) Calculation of trunk and pipe sizes;

(13) Calculation of ìn�duct' and `break�out' noise levels in mannedcompartments and assessment of all the acoustic insulationrequirements;

(14) Calculation of space relative humidities and identification ofhumidification requirements;

(15) Statement of electrical requirements, including crash stopping of fans;

(16) Table of weights.

e. During this design stage, to augment the calculation sheets and equipment listsindicated above, the following drawings are to be prepared, continuallyup�dated as necessary and submitted to the MOD immediately prior to the handover of the vessel so that calculations and drawings reflect the completed HVACsystems.

(1) Scaled single line Àir Systems � General Arrangement' � drawings on deckplans showing:

(a) All air systems, i.e. essential, non�essential, hazardous, fresh,smoke clearance, natural and mechanical ventilation;


March 2000

3.3

(b) Position of ATU and other air/water and water/water heatexchangers;

(c) Position of AFU;

(d) Zonal boundaries and watertight subdivision;

(e) Siting of fans, heaters, filters, moisture eliminators, valves andother fittings;

(f) Type, size and number of terminals fitted in each space;

(g) Sizes of trunks;

(h) Extent of watertight and gastight trunking;

(i) Citadel boundary.

(2) Air balance diagrams for each NBCD/fire zone and machinery space todemonstrate that in `closed down' conditions:

(a) Recirculation routes from air�conditioned compartments back tofan intakes are unobstructed by doors, hatches, fire curtains, etc.;

(b) Access to and from adjacent zones will not be hampered byunacceptable differential air pressures;

(c) Hot, oil contaminated air will not migrate from the machineryspaces into the citadel.

(3) Planimetric drawings of each essential and non�essential chilled watersystem indicating:

(a) All pipe runs, tee junctions, bends, etc.;

(b) All air/water and water/water heat exchangers and thecompartments/equipments supplied by each one;

(c) All control panels, filters, flow switches, air vents, sampling points,isolating valves and other fittings inserted in the pipelines;

(d) The CWP and pumps, with cross connections where applicable;

(e) Pipe lengths and diameters between junctions for both flow andreturn pipes;

(f) Flow of CW in m3/s through each pipe section.

(4) Scaled single line `CW Systems � General Arrangement' drawing on deckplans showing:

(a) Pipe routes;

(b) Position of CWP and pumps;

(c) Zonal subdivision;

(d) Position and classification of each heat exchanger, i.e. essential,non�essential or stand by.


3.4

3.3 Design Leading to Contract Definition

a. During this stage the air�conditioning and ventilation systems are to becontinually amended and up�dated to reflect changes made in the overall shipdesign. In addition the many and varied estimates, used during the feasibilitystage, are to be progressively refined and confirmed with the calculations,equipment selections, drawings, etc., produced during that stage, beingre�assessed as necessary.

b. By the end of this stage the following is to be complete:

(1) All basic design data confirmed;

(2) Classification and grouping of compartments agreed;

(3) All calculations of air flows, CW flows, trunk and pipe sizes finalized;

(4) Selection of equipments and materials approved and where appropriateconfiguration definition packages prepared;

(5) Selection of fittings agreed and where appropriate new types of fittingstested and approved for use;

(6) Upgrading of `Air Systems � General Arrangement' drawings to doubleline convention;

(7) Upgrading of `Chilled Water Systems � General Arrangement' drawings toshow supply and return leads and siting of all fittings included in thepipework;

(8) CW planimetric, air balance diagrams, upgraded general arrangements,configuration definition packages, etc., are all to be brought toModification State Zero, i.e. the stage at which the MOD will become theDesign Authority (DA) for support;

(9) Electrical requirements finalized;

(10) Statement of Requirements for Total Ship System and Design Critiqueprepared and agreed.

3.4 Detailed Design

a. Large scale layout drawings of compartments and spaces are to be producedwhich accurately show the final positions and sizes of all CW and condensatepipes, air�conditioning and ventilation trunking, equipments and fittings,electrical leads and controls, etc., that are associated with the air�conditioningand ventilation of the vessel. These drawings are also to show the clear accessareas that are required to enable items, such as filters and fan motors, to bewithdrawn for servicing.

b. Drawings are to be prepared to demonstrate the method of handling heavyequipments, such as fans, heat exchangers and AFU in congested areas toenable repair or replacement of these equipments to be carried out at sea.

c. All drawings, equipment lists, data sheets, etc., prepared during the previousstages are to be amended, as necessary, to reflect the final ship fit.

d. Throughout all stages of the design the symbols and line conventions used whenproducing the required drawings are to be in accordance with NES 707 Parts 1& 2 and BS 1553 Parts 1 & 3.


March 2000

4.1

4. DESIGN DATA

Related Documents: ISO 7547 and NES 111; see also Annex A.

a. The calculation of heating and cooling loads and the sizing of pipes and ductingcan be carried out by manual methods or by computer programs. In either casethe calculations are to be based upon the design data given in this section andproven established processes such as Building Services Research IndustrialAssociation (BSRIA), Engineering System Design Methods (ESDM), CivilInstitute Building Services Engineering (CIBSE) and International StandardsOrganisation (ISO) 7547, etc.

4.1 Environmental Design Conditions

a. External Temperatures (Hot Climates)

Climate Dry Bulb(DB)�C

Wet Bulb(WB)�C

SurfaceSea Temperature �C

Tropics 35 30 33

Temperate Summer 30 24 29

b. External Temperatures (Cold Climates)

Climate Dry Bulb(DB)�C

Wet Bulb(WB)�C

SurfaceSea Temperature �C

Temperate Winter -4 N/A 2

Sub-Arctic -10 N/A –1

Arctic -29 N/A –2

c. Internal Temperatures � Air�conditioned Spaces (unless otherwise specified insubsequent sections):

(1) Tropics:

(a) All compartments, except galley complex, 23.5°C EffectiveTemperature (27.0°C DB/19.6°C WB);

(b) Galley complex, 29°C Effective Temperature (34.5°C DB/26°C WB).

(2) Temperate Summer:

(a) All spaces except the galley complex, 23.5°C Effective Temperature(27°C DB/19.6°C WB);

(b) Galley complex, 25.5°C Effective Temperature(29.5°C DB/21.5°C WB).

(3) All Cold Climates:

(a) All manned spaces unless otherwise specified 22°C DB minimum.


4.2

d. Internal TemperaturesVentilated Spaces (unless otherwise specified insubsequent sections):

(1) All Hot Climates:

(a) All spaces, except galleys where the TACS concept is not required,unmanned electrical compartments, main and large auxiliarymachinery spaces, compartment temperature above weatherambient temperature;

(b) Galleys, etc., and unmanned electrical compartments, the spacetemperature restricted to 10°C above weather ambient.

(c) Main and large auxiliary machinery spaces, in `open ship' condition,temperature rise above external ambient restricted to 15°C. (for`closed down' condition, see Section 8).

(2) All Cold Climates:

(a) All spaces, in all operating conditions, 13°C DB minimum.

(b) Main and large auxiliary machinery spaces, in the `deadship'condition, 10°C DB minimum, i.e. alongside with only hotel servicesrunning.

4.2 Cooling and Heating Assumptions

a. The cooling and heating loads for each compartment are to be assessed on thebasis of the following assumptions:

(1) Cooling conditions:

(a) Solar radiation occurs on exposed surfaces, weatherdecks and bothsides of the ship simultaneously except for compartments extendingthe full width of the vessel when solar radiation is to be assumed onone side only;

(b) No shade is cast by superstructure, funnels, masts, etc.;

(c) Internal wild heat sources are at maximum value, excludingstandby equipments;

(d) Maximum number of personnel are in each compartment,considered individually. Number of personnel in dining halls,recreation spaces, ward rooms and ante rooms, etc., are to be themaximum likely to attend film shows and functions, as appropriate;

(e) Should the ship be fitted with current in�service equipment then inany compartment the heat gained from the fan and fan motor isequal to 14% x sum of cooling sensible heat gains for thatcompartment However, should the equipment fitted be to goodcommercial marine standards then this figure would revert to 7%;

(f) Although it is specified in Clause 4.2a(1)(d) above that themaximum number of personnel be allowed for when calculatingcooling loads on an individual compartment basis, this would resultin an overall cooling capacity for numbers far in excess of the shipscomplement. Therefore, on completion of cooling calculations, theduplication of manning levels should be determined and the overallcooling capacity reduced accordingly. Allowances for heat gainsfrom personnel are given in Clause 4.3.e.


March 2000

4.3

(2) Heating conditions:

(a) Internal wild heat sources are at minimum value, i.e. maximumvalue � 40%;

(b) No heat gained from personnel;

(c) No heat gained from adjacent compartments where the maintainedtemperature is non specific;

(d) No heat gained from solar radiation;

(e) Heat gained from fan and fan motor is the same as for coolingconditions;

(f) Heat is lost to adjacent cooler spaces;

(g) Heat is lost through the superstructure to sea and air.

4.3 Total Heat Transfer Coefficient ‘k’

a. Total heat transfer coefficients are to be calculated in accordance with theformula quoted in ISO 7547 (Clause 5.2.4) using the thermal conductivities forcommon materials as given in Annex B of that standard and/or publicationsfrom BSRIA or CIBSE. The Table 2 figures given in the ISO as typical heattransfer coefficients for various types of boundaries are not to be used for RNships, as insulation materials, thicknesses and standards can vary considerably.For Cold and Cool rooms see NES 111.

b. The wild heat generated by equipments is to be based upon the actual powerratings obtained from the equipment manufacturers. In the early stages of thedesign such information is not always available and it will be necessary to makethe best possible estimates, e.g. rule�of�thumb methods such as the values givenin the following table for the heat gain from compartment lighting:

Compartment Heat gain from general lighting (W/m2)pType Incandescent Flourescent

Cabins, etc. 15 8

Mess or dinning rooms 20 10

Gymnasiums, etc. 40 20

c. When calculating the maximum heat load generated by galley equipment thefollowing criteria is to be used:

(1) From the galley equipment's maximum electrical power inputs andemploying diversity factors of 0.2 for thermostatically controlled itemsand 0.5 for manually switched heat controlled items, also assessing themaximum projected usage of equipment, a peak power input figure isarrived at, e.g.

Shallow fryers 15.0 kW input@ 0.2 = 3.0 kW

Deep fryers 30.0 kW input@ 0.2 = 6.0 kW

Hot plate/ovens 50.0 kW input@ 0.5 =25.0 kW

Grilles 6.0 kW input@ 0.5 = 3.0 kW


4.4

Tilting kettles 20.0 kW input@ 0.5 =10.0 kW

Other items 20.0 kW input@ 0.5 =10.0 kW

Total diversified input =57.0 kW

d. This diversified electrical power input is then to be converted into a heatemission into the galley and this is arrived at by using a further diversity factorof 50%, e.g. total diversified input of 57.0 kW = 57.0 x 50% = 28.5 kW heatemission.

e. The wild heat generated by personnel is to be taken as:

Sensible heat = 45 Watts/man;

Latent heat = 135 Watts/man.

f. When separate sleeping and recreational areas are contained within a singlemess deck the above allowances are to be increased to 55 Watts and 165 Wattsrespectively.

4.4 Relative Humidity

a. In air�conditioned compartments, in all climatic conditions, the design relativehumidity is to always lie between 65% and 30%. In accommodation and mannedoperational spaces a lower limit of 45% is to be applied and only in veryexceptional circumstances is the RH to fall below this figure.

4.5 Air Distribution Systems

4.5.1 Design Margin

a. When selecting fans for air�conditioning and ventilation systems the design airvolume is to be increased by a 10% margin, calculated on the system constantorifice line (See Section 10). Trunk sizing calculations are then to be carried outusing the design air flow and the related total fan pressure as indicated by theconstant orifice line.

4.5.2 Air Velocities

a. In air�conditioning and ventilation systems serving operational, habitationalaccommodation, office spaces and other manned working areas the trunked airvelocities are generally to observe the following criteria :

Initial design velocity 10 m/s;

Maximum permissible velocity 12.5 m/s.

b. In compartments or spaces with low noise target levels every effort should bemade to ensure that duct configurations are so designed that velocities areretained at levels which would not result in noise generation.

c. Compartments other than those indicated above where noise target levels arenot as restrictive may be served by air�conditioning and ventilation systemswith higher velocities to facilitate space restrictions.

d. The maximum design air velocities through various types of aperture are to beas follows:

(1) Recirculation grilles in bulkheads � 2.5 m/s calculated on the clear area;


March 2000

4.5

(2) Supply inlets and exhaust outlets with the exception of spray eliminatingjalousies � 5 m/s calculated on the clear area;

(3) Spray eliminating jalousies � 5 m/s calculated on the face area;

(4) Slotted trunks, (supply and exhaust):

(a) Vertical velocity through slot 4 m/s;

(b) Horizontal velocity through slot 10 m/s.

(5) Punkah louvres, diffusers, linear grilles, etc., discharge velocity � 3 m/s;

(6) Flame proof gauze � 5 m/s calculated on the clear area;

(7) Dust filters � 2.5 m/s.

e. The maximum face velocity of air passing through a CW/air heat exchangerwithout a moisture eliminator fitted is to be restricted to 2.0 m/s. Moistureeliminators should not be fitted unless absolutely necessary, however if one is tobe fitted then the face velocity across the heat exchanger can be increased to amaximum of 3.0 m/s.

4.5.3 Fresh/Filtered Air Requirements

a. Within the NBCD citadel the fresh air requirement is to be individuallyassessed for each NBCD/fire zone and is to be sufficient to:

(1) Overcome the calculated uncontrolled leakage and thereby generate thespecified zone pressure. This is to be calculated based on an allowance of900 m3/hr of filtered fresh air for every 3,400 m3 of citadel volume abovethe deep water line;

(2) Overcome the known controlled purging exhaust requirements in a `openship' condition;

(3) Overcome the known controlled purging exhaust requirements in a`closed ship' condition;

(4) Purge Cleansing Stations giving specified number of air changes perhour;

(5) Purge Air�Locks giving specified number of air changes per hour;

(6) Replenish oxygen levels and thereby keep CO2 content below maximumpermitted levels (See Section 9 Clause 9.4.3);

(7) Overcome the air lost from the citadel other than purging requirements.The amount of filtered fresh air required will therefore be the greater ofthe sum of 2 + 6 + 7 in an `open ship' condition or the sum of 1 + 3 + 4 + 5+ 6 + 7 in a `closed ship' condition.

Details of the above calculations are also shown in Section 9.

b. In machinery spaces, when required, under `closed down' conditions, sufficientfresh air is to be provided to compensate for known controlled losses andcalculated uncontrolled leakages while maintaining a differential pressure ofapproximately 3 millibars (mbars) relative to the external atmosphere.


4.6

c. To prevent ingress of smoke or fumes, selected essential compartments are to bepressurised to between 1 and 1.5 mbars, relative to their surrounding spacesand automatic closures are to be fitted at any recirculation openings and nonreturn features incorporated in the branch trunks supplying these spaces.

4.5.4 Standard NBC Filters

a. The air flow through a single Standard Radial NBC Filter is to be 300 m3/hr± 10%.

b. The number of Standard Radial NBC Filters required in an AFU is to becalculated by dividing the total air flow required from the AFU by 300 and,where necessary, rounding up.

4.6 Pressurization

4.6.1 Citadel and Zones

a. Within the NBCD citadel, in the fully `closed down' condition with citadel andzonal boundaries secured with Air Lock and Cleansing Station disciplinesenforced, the over pressure in any fire/smoke zone, relative to the externalatmosphere, is to be between 5 mbars and 8 mbars. This will be achieved by theuse of non�return air bleed valves at Air Locks, Cleansing Stations and otherlocations where controlled leakage is required. Air bleed valves may also benecessary to relieve any overpressure created by the `calculated uncontrolledleakage' being overestimated, i.e. in the event of the vessel being built `tight'.With the proper allocation and setting of the above air bleed valves thedifferential pressure between adjacent fire/smoke zones will not exceed theallowed 0.5 mbars.

4.6.2 Machinery Spaces

a. In a main machinery space where an overpressure is to be generated in a fully`closed down' ship, the said overpressure shall be 3 mbars relative to theexternal atmosphere. These machinery spaces will normally be cooled by airrecirculating through CW/air heat exchangers and will have a fresh air supplysufficient to balance the sum of any known controlled leakages to suit exhaustpurging requirements and the calculated uncontrolled leakages based on theallowance of 0.5�air changes per hour on the gross volume, including casings ifopen to the machinery space. In exceptional circumstances where spacerestrictions on the vessel preclude the addition of dedicated Air Filtration Unitsand fresh air supplied to the ships citadel is sufficient, then the fresh airrequired to pressurise the machinery space may be bled off from the citadel,with the proviso that all fire protection requirements are met and the integrityof the citadel is maintained.

4.7 Heating Systems

a. The minimum temperature of fresh air supplied direct to compartments andspaces within the citadel is to be 13°C.


March 2000

4.7

b. In air�conditioning systems the temperature of the mixed fresh andrecirculated air before the inlet to main heater or fan, whichever is appropriate,is not to fall below 4.5°C in cold climates.

c. In grouped systems where one heater may serve several compartments thevariation in the design supply temperatures is not to be more than 3°C.

d. The maximum temperature at which air is to be supplied to any compartment is32°C.

e. In compartments within the NBCD citadel both the air�conditioned andmechanically exhausted air flows used when heating, are to be the same as thosecalculated for cooling.

f. In cold climates, in compartments outside of the NBCD citadel which do nothave a stated minimum air change requirement, the air volumes delivered bymechanical ventilation systems to maintain temperatures below specificmaximums in hot climates are to be reduced by 50% or to 0.005 m3/s per man,whichever is the greater.

4.8 Chilled Water Systems

4.8.1 Design Margins

a. CWP for both essential and non�essential systems are to provide a pre�selectedgrowth margin calculated on the total connected cooling load of the system (SeeSection 6 for the method of selecting CWP).

b. CW pumps are to be selected to provide a flow capacity 10% greater than thecapacity of the plant it serves.

c. Pipe connections between CWP, CW pumps, main risers, distribution mains andpipe leads to backup water/water heat exchangers for essential systems are to beincreased by at least one standard nominal diameter over the calculated designsize.

d. Water/water backup heat exchangers, for essential systems, are to be capable ofcoping with the appropriate system design connected cooling load plus a growthmargin of 25%.

4.9 Chilled Water Temperatures

a. The design temperatures at the CWP are:

(1) Supply to heat exchangers 6.5°C;

(2) Return from heat exchangers (full load) 13.5°C.

b. In non�essential systems, served by two or more CWP, the mixing maintemperature on light load is not to be greater than 9°C.

c. In essential systems the CW is to be supplied to the heat exchangers servingweapons cabinets and other electro�technical equipments at a temperature of9°C ± 2°C.


4.8

4.10 Velocities and Pipe Size

a. In all systems the CW flow is to be within the limits of 4.5 m/s and 2.0 m/s andthe minimum pipe diameter is to be 16 mm. In exceptional cases, possibly wherea bank of electronic cabinets is to be served, these requirements may beincompatible due to the small quantities of CW needed. In such circumstancesconsideration is to be given to connecting the heat exchangers in series andadjusting the CW flows to obtain the necessary cooling.


March 2000

5.1

5. AIR DISTRIBUTION SYSTEMSRelated Documents: ISO 9785, NES 101 Part 2, NES 111, NES 121, NES 123 Part 1,NES 183 Part 1, NES 519, NES 593, NES 763, NES 1004, BR 1754, Form SSCF 4; seealso Annex A.

5.1 Design Objective

a. The design of the total air distribution system for any vessel is to ensure that:

(1) Noxious odours, toxic and dangerous fumes, and other contaminants arewithin the permitted `Health and Safety' concentrations and areconstrained in specific compartments;

(2) Acceptable oxygen levels are maintained for personnel efficiency,combustion and other oxidation processes;

(3) In a fire situation, smoke migration is restricted to defined zones and postfire contamination is cleared with minimal loss of operationaleffectiveness;

(4) A positive pressure, relative to the external atmosphere, can be achievedand maintained within the NBCD citadel and machinery spaces whenrequired;

(5) Watertight, gastight and smoke�tight integrity is not impaired;

(6) Air is distributed as best suited to particular compartment functionspersonnel comfort and equipment cooling;

(7) Acceptable compartment conditions are maintained at all times inmanned compartments.


a. Exhaust discharge openings are to be sited well clear of any potential sources ofignition or reingestion, the exhaust outlets being on the opposite side of the shipto supply inlets. Where this is not possible, the positioning and protection ofweatherdeck inlets to AFU, ventilation systems, compressors, etc., is to ensurethat no foul air is drawn in from nearby exhausts.

b. Exhaust outlets are not to be positioned to discharge across walkways.

c. All weatherdeck openings, where appropriate, are to be fitted with sprayeliminators and self draining terminals that will cope with the most extremeenvironmental conditions and satisfy the relevant standards specified inNES 1004.

d. Where practicable, all weatherdeck ventilation openings to systems servingcompartments within the NBC citadel, with the exception of inlets to AFU, areto be fitted with a butterfly valve sited in the trunk leading from the openingand as close to the ship's side as possible. Trunking between the ship's side andthe valve is to be gas tight (See also Clause 11.8.e).

e. Weatherdeck openings to systems serving compartments outside of the citadelare to be fitted with butterfly valves as above (See also Clauses 11.8.f and11.8.g).

f. Filters are to be fitted to prevent fan systems and equipment being coated withairborne dust and fibres, resulting in reduced performance and possibleblockage (For details of siting and types of filters see Section 12).


5.2

g. Easy access arrangements are to be provided throughout all systems to allowducting to be internally inspected and cleaned. This is especially importantwhere trunking is subject to high fouling rates, e.g. galley, laundry, bathrooms,WC, etc.

h. In air�conditioned and mechanically ventilated spaces (except for mainmachinery spaces) linear grilles, punkah louvres or diffusers, as appropriate,are to be fitted in supply trunking, routed within the compartment, to providean even distribution to manned positions and to disperse wild heat.

i. Where the majority of the distribution diffusers on a system can be closed by theoccupants, a pressure relief valve is to be fitted in the ATU downstream of thefan discharge.

j. Trunked exhaust and recirculation terminals within the spaces served aregenerally to be linear grilles or similar. Recirculation from spaces to passages isto be via light tight grilles incorporated in escape panels, suitably protectedopenings in bulkheads or 30 mm air gap at top or bottom of doors, asappropriate.

k. ATU and AFU are to be sited within the NBCD/fire zone that contains thecompartments they serve.

l. Free flow recirculation routes are to be unobstructed and are not to rely upondoors and hatches in watertight boundaries remaining open. Watertight risk,damage control and NBCD markings are not to be compromised to obtain airflow routes but in extreme cases valved, watertight `jumper' trunks are to befitted to bridge decks and watertight bulkheads.

m. Voids formed between linings and deckheads are not to be used in lieu of supply,exhaust or recirculation trunks and they are not to be considered asunobstructed for the free flow of recirculated air. Recirculation grilles fitted indeckhead linings are to be trunked to the nearest passage bulkhead andterminated in a suitably screened opening.

n. All access openings between NBCD citadel and machinery spaces and betweenNBCD citadel and external atmosphere, that are required in the `closed down'condition are to be protected by Cleansing Stations or Air Locks. CleansingStations and citadel accesses to the weatherdecks are to have the Air Locks airpurged (See Section 9).

o. Within the citadel, in both the `open ship' and `closed ship' condition, eachNBCD/fire zone is to have a balanced supply and exhaust. It is essential that airdoes not flow across zonal boundaries in the `open ship' condition when accessis allowed between zones through boundary doors.

p. For air distribution within machinery spaces (See Section 8).

5.3 Air-conditioning Arrangements

a. Conditioned air is to be distributed via essential and non�essential ATU each ofwhich is to consist of a 25 mm thick filter protecting an appropriate fan andair/CW cooling coil engineered as a package.

b. Condensation collection and drainage arrangements are to be provided. Thedrainage system must be effective against all levels of static air pressuregenerated at the cooling coil and must not be dependent upon manual primingof a dry system.


March 2000

5.3

c. If there is a risk of condensation carry over into the distribution system,moisture eliminators are to be fitted.

d. Air is to be distributed to, and within, compartments by trunking connected tothe fan outlet. The recirculation of air back to the ATU inlet can either be`open' (i.e. the ATU inlet is open directly to the compartment in which it issituated) or `trunked', depending upon the type of compartment being servedand the position of the ATU.

e. ATU are to be identified as either `Central ATU' or `Compartment ATU' and theselection of a type for a particular duty is to be based upon the followingcharacteristics.

5.4 Central ATU

a. Are to be fitted in dedicated compartments, sited centrally within particularfire zones, with other fans that serve spaces within that particular zone.

b. Are to serve all essential systems.

c. Are to serve all non�essential group systems that supply more than onecompartment or compartment complex.

d. Fresh air for ATU with open recirculation is to be trunked to the ATUcompartment which is to act as a mixing chamber for these systems. Wheretrunked recirculation is fitted the fresh air is to be delivered into therecirculation trunk upstream of the filter to ensure the air is thoroughly mixedbefore it passes over the cooling coil.

5.5 Compartment ATU

a. Are to serve only non�essential, single compartments or compartmentcomplexes where the space available and cooling load make them appropriate,e.g. Dining Hall, Recreation Spaces, Laundry, Sick Bay, etc.

b. The filter, fan, cooling coil and if required, moisture eliminator are to bepackaged and enclosed in a suitable container to be sited within thecompartment served.

c. Local controls are to be provided to enable ATU performance to be matched tocompartment conditions.

d. Where convenient the main heater with local controls is to be included in theATU package.

e. The fresh air required by the compartment is to be trunked direct from the AFUto the ATU or adjacent to the enclosure.

NOTE When designing, and installing Compartment ATU it is emphasized that:

(1) The noise and vibration standards appropriate to the compartmentserved must be achieved;

(2) Condensation must be contained, collected and removed withoutmigrating into the compartment and on no account are CW pipes to be ledover living, sleeping, eating areas, etc.


5.4

5.6 ATU Controls

a. Where the cooling load on any ATU can vary significantly, either in the shortterm, due to the movement of personnel or change in equipment status, or inthe long term, due to changes in climate, controls are to be provided at the ATUthat will allow the cooling performance to be matched to the compartmentconditions.

b. The required control is to be achieved by restricting:

(1) The flow of CW through the cooling coil;

or

(2) The flow of cooled air to the compartment(s) using variable volume fans;

or

(3) A combination of both options.

c. Where control is achieved by restricting the air flow, care is to be taken that theminimum velocity across electrical heaters is maintained to avoid constantlytripping and that with compartments fully manned, the CO2 content of the airdoes not rise above permitted maximum levels.

d. Reduction in CW flow is to be achieved by fitting thermostatically controlled,three way, diverter valves in the ATU control panel (See Section 6).

e. Details of main heater controls are given in Section 8.

5.7 Special Requirements

5.7.1 Operational Spaces

a. These essential spaces are to be air�conditioned with open recirculation back toan ATU. The fresh air requirement is to be trunked to the ATU and therequirements of Clause 5.6.a considered.

b. Supply terminals giving directional control of the air flow are to be sited atmanned positions with diffusers or similar terminals positioned to disperseheat from equipments.

c. To prevent smoke entering selected Essential compartments in a fire situation,a positive pressure of 1 to 1.5 mbars relative to the surrounding spaces is to bemaintained. Non return air bleed valves can be fitted to the recirculation grillesand shut off features incorporated on the ATU supply system serving thecompartment to restrict smoke entry when the fans are stopped.

5.7.2 Accommodation and Recreation Spaces

a. These spaces are to be air�conditioned with open recirculation back to an ATU.The fresh air requirement is to be trunked to the ATU and the requirements ofClause 5.6.a implemented.

b. For combined sleeping and recreation spaces:

(1) Of the total air supplied to the space, 80% is to be supplied direct to thesleeping area and 20% direct to the recreation area;


March 2000

5.5

(2) The total recirculation is to be taken from the recreation area only, so thatall the air supplied to the sleeping area will pass through the recreationarea;

(3) A controllable air flow of between 0.005m3/s and 0.01m3/s is to beprovided to each bunk, the total quantity supplied to bunks being at least50% of the total air flow delivered to the sleeping area. The remaining airsupplied to the sleeping area is to be evenly distributed throughout thecompartment.

c. For cabins and sleeping areas:

(1) Where more than one bunk is fitted an individual, controllable, air flow of0.005m3/s and 0.01m3/s is to be provided to each sleeping position, theremainder of the air being distributed evenly throughout thecompartment;

(2) In single berth cabins an even distribution of cooled air is to be providedby linear grilles or diffusers.

5.8 Medical Spaces

5.8.1 Sick Bays

a. Sick bay complexes are to be air�conditioned by dedicated ATU with fullytrunked distribution, fresh air, recirculation and where necessary, exhaustsystems. The Medical Complex is to maintain a positive pressure in relation toadjacent compartments surrounding the complex in order to prevent theingress of any possibly contaminated air thereby ensuring sterility. Similarlythe Operating Theatre is to have a relative positive pressure in relation to theadjacent Medical Compartments. Fresh air make up is to be via a NBC AFUwith by�pass arrangements. Sick bays are to be served by one of two systemconfigurations, the particular one being chosen by the size, type and number ofcompartments involved.

b. Temperatures within the Complex are to be maintained as follows:

(1) Heating 22°C DB minimum ± 1°C;

(2) Cooling 23.5°C Effective Temperature (27°C DB/19.6°C WB/RH 50%).

c. The ambient temperature in some compartments, typically the OperatingTheatre, Treatment Room/Dispensary and Surgery is to be capable of beingquickly adjusted by the surgeon as dictated by the patient's condition.Designated compartments and temperature ranges required are to be specifiedat the outset of the design.

d. Where a complex includes dedicated WC, showers, bathrooms, etc., the total airflow through and the positioning of terminals within these spaces is to be suchthat toxic and noxious odours are speedily cleared without migration to othercompartments and condensation is minimised.

e. In Operating Theatres high level and low level exhausts are to be provided, lowlevel exhausts are to be sited as close to the operating table as possible. Supplyterminals, with a minimum outlet velocity of 3 m/s, are to be arranged on bothsides of the operating table to give a uniform overall distribution.


5.6

f. In combined Sick Bays and at Emergency Operating Stations (EOS), undernormal conditions, air is to be distributed evenly throughout the space but it ispossible to reconfigure the distribution system so that when the operating tableis in use an arrangement similar to that installed in Operating Theatres isavailable. The two possible system configurations indicated in Clause 5.8.1.aare as follows.

5.9 Configuration No 1 (Full fresh air cooling)

a. This type of system is to be used for small complexes or for sterile compartmentsin larger complexes where it is possible to ventilate all compartments usingair�conditioning and exhaust systems without incurring a significant increasein either the numbers of AFU required or the total connected cooling load.

(1) The total air flow required is to be trunked direct from the AFU fan outletto the inlet of the dedicated ATU.

(2) The ATU is to be capable of cooling or heating the air to the standardspecified and distributing it as required throughout the medicalcompartments. All the air is then to be discharged directly overboard, viathe potentially contaminated or noxious spaces within the complex, by atrunked mechanical exhaust system.

(3) The exhaust system is to be balanced such that the requirement atPara 5.8.1a is maintained.

(4) This configuration requires all the air delivered to the complex, or sterilecompartments as indicated above, to be treated as a known leakage whenassessing AFU capacities and numbers.

(5) The total air flow to the complex is to be comprised of a quantity of freshair to:

(a) Keep CO2 content below the permitted maximum levels with allcompartments fully manned and occupied;

or

(b) Equal the amount of air required to be exhausted from designatedcompartments (a minimum 15�air changes per hour).

Whichever is the greatest, plus any additional air required forair�conditioning purposes.

5.10 Configuration No 2 (Semi-recirculation)

a. This system is to be adopted when full fresh air cooling is impractical due to itsimpact on the total connected cooling load and/or on the number of AFUrequired in the fire zone that contains the medical complex. It combines onededicated ATU configured as outlined above to serve designated sterilecompartments and a fully trunked air�conditioning system with a mechanicalexhaust as follows:


March 2000

5.7

(1) Compartments within the complex would normally be classified at theoutset of the design as either:

(a) Undesirable to recirculate air from, e.g. sterile compartments,WC's, sluices, etc.;

or

(b) Unlikely to contain pollutants, e.g. Consulting Room, office,dispensary, etc.;

Compartments in (a) above would form the full fresh air unit andcompartments in (b) would form the part fresh air/recirculation unit;

(2) Dependant on the method used for the calculation of the fresh airquantities required for the vessel, the total air flow via the mixed freshair/recirculation ATU is to be comprised of a quantity of fresh air to:

(a) keep CO2 content below the permitted maximum levels with allcompartments fully manned and occupied;

or

(b) Equal the amount of air required to be exhausted from designatedcompartments (a minimum 15�air changes per hour);

Whichever is the greatest, plus any additional air required forair�conditioning purposes;

(3) The total fresh air and the air recirculated from Class B compartments isto be fully trunked to the ATU inlet, heated or cooled as required anddistributed throughout the complex;

(4) All the air from compartments classified as `undesirable to recirculatefrom' is to be discharged directly overboard by a mechanical exhaustsystem such that the requirements of Clause 5.8.1.aare met;

(5) The total air handled by the exhaust system is to be treated as a knownleakage when assessing AFU numbers.

5.10.1 Dental Surgery

a. This space is to be air�conditioned and may be included as part of the medicalcomplex or any other adjacent system. A supply, diffuser type terminal is to bepositioned to give maximum air movement at the dental chair.

5.11 Bathrooms and WC

5.11.1 General Requirements

a. All systems serving these spaces, whether air�conditioned supply, fresh airsupply, mechanical exhaust or recirculation, are to be fully trunked and theATU (or CW unit coolers, see Section 6) are to be dedicated to these spaces.

b. Where practicable and economic, bathrooms, WC and urinals, within a fire zoneshould be grouped together and served by the same system.


5.8

c. Where practicable and economic each space is to be served by dedicated odourfilters to ensure that all noxious and undesirable odours are removed from therecirculating air before it is redistributed and cross contamination does notoccur between compartments on a group system. The siting of odour filters is toensure that the moisture content of the air passing through them is as low aspossible.

d. A negative pressure relative to surrounding compartments is to be maintainedwithin these spaces by arranging a balanced supply and exhaust/recirculationairflow but ensuring that a greater negative pressure is available at theexhaust/recirculation terminals relative to the supply terminals positivepressure.

5.11.2 WC and Urinals

a. The distribution systems for WC and urinals are to be designed to achieve twoprime objectives, viz:

(1) Maintaining of temperatures, relative humidities and oxygen levels toair�conditioning standards under `open ship' and `closed down'conditions in all types of climates. In `closed down' conditions, the periodis to be indefinite unless the STR for the vessel states otherwise;

(2) The removal of all noxious and undesirable odours from these spaceswithout any other compartment or space being polluted.

b. To achieve these objectives the total air flow through any WC and/or urinalspace is to be sufficient to:

(1) Ensure 15 complete air changes per hour within the compartment;

or

(2) Satisfy the minimum air requirements for WC cubicles, urinals andwash�basins contained within the space when these spaces aremechanically ventilated and not air conditioned;

or

(3) Maintain air�conditioning standards in all climatic conditions.

Whichever is the greatest.

c. The type of systems used for WC and urinals are to be tailored to thecircumstances within individual compartments and, to obtain the mosteffective and economic performance, system designs may vary throughout theship.

d. Within the compartments a minimum of 0.035 m3/s of air is to be taken fromeach WC cubical and urinal and 0.02 m3/s is to be taken from each wash�basin(See Clause 5.11.2.b(2) above).

e. In WC cubicles the supply terminal is to provide approximately 0.015 m3/s andis to be so positioned to enable a downward jet of air to be delivered inside thedoor. The exhaust/recirculation terminal is to be positioned at the rear of thecubicle at deckhead level.


March 2000

5.9

f. Recirculation/exhaust terminals are to be positioned directly above urinals, atdeckhead level.

g. The supply air, other than that required for WC cubicles, is to be evenlydistributed throughout the compartment, care being taken to ensure that noshort circuiting takes place between supply and exhaust/recirculationterminals.

h. Individual WC that are remotely sited can be exhausted directly overboard bycombining them with the mechanical exhaust systems from hazardous spaces,providing that a dedicated exhaust fan has not been specified. The supply tothese compartments can be taken from an adjacent air�conditioning system ordirect from the citadel via a bulkhead opening. In such cases an odour filter isnot required and the exhaust is to be treated as a known leakage when assessingAFU requirements.

5.11.3 Bathrooms

a. Air distribution systems for bathrooms are to be designed to achieve two primeobjectives, viz:

(1) Maintaining of temperatures, relative humidities and oxygen content toair�conditioning standards under `open ship' or `closed down' conditions,in all climatic conditions and at all compartment operating levels. In the`closed down' state, the period will be indefinite unless specifiedotherwise in the STR for the vessel;

(2) The prevention of excessive condensation occurring on ship's structure atany level of manning or operation within the compartment and in anyclimatic condition.

b. To achieve these objectives the total air flow through any bathroom is to besufficient to:

(1) Ensure 15 complete air changes per hour within the compartment;

or

(2) Satisfy the minimum air requirements for each bath, shower andwash�basin, when the space is mechanically ventilated and not airconditioned;

or

(3) Maintain air�conditioning standards in all climatic and compartmentconditions;

Whichever is the greatest.

c. The systems are to be tailored to individual bathrooms and their design mayvary throughout the ship, the main priority being the attainment of theobjectives in the most effective and economic manner.

d. A minimum air flow of 0.035 m3/s is to be recirculated from each shower andbath space and 0.02 m3/s from each wash�basin (See Clause 5.11.3.b.(2) above).


5.10

e. The supply is to be distributed throughout the compartment with aconcentration at the drying positions.

f. Heaters serving bathrooms are to be sized to provide a temperature of 22°C atdrying/undressing positions in cold weather conditions.

g. Bathroom usage is cyclic, and to counter overcooling during periods ofminimum manning and operation in temperate climates, the diversion of CWby thermostatic control valves or the use of reheaters is to be considered.

h. Where practicable and cost effective, to limit condensation, dehumidifiers maybe installed to augment the removal of moisture from the air during periods ofhigh manning in warm climates. These units are to be manufactured to `goodcommercial marine standards' and engineered to cope with all expected shipmotions and attitudes.

i. Private bathrooms are to be included with the relevant compartments andair�conditioned as a group, the recirculation being trunked back to the ATU andan odour filter fitted in the branch from the bathroom/WC. Alternatively wherethe fresh air bleed�off from the grouped compartments is equal to or greaterthan the total air flow required in the bathroom sufficient air may be exhaustedvia the bathroom and discharged directly overboard by a convenientmechanical exhaust ventilation system.

5.12 Galleys and Associated Spaces

5.12.1 Galley, Servery and Scullery

a. These spaces, treated as a group, are to be air�conditioned or partiallyair�conditioned with selected equipment being mechanically exhausted. Theair�conditioning is to be by a dedicated ATU with a fully trunked distribution,recirculation and fresh air system. These spaces are to be capable of operatingin the `closed down' state indefinitely or to the period specified in the STR of thevessel.

b. Odour filters are to be fitted to ensure that all odours are removed from therecirculating air before it is redistributed throughout the compartments. Thesiting of these filters is to ensure that the moisture content of the air passingthrough them is as low as possible.

c. A negative pressure, relative to the surrounding compartments, is to bemaintained within these spaces by arranging a balanced supply and exhaustairflow but ensuring that a greater negative pressure is available at theexhaust/recirculation terminals relative to the supply terminals positivepressure.

d. All trunking within the galley and throughout the respective systems is to beconstructed of mild steel with welded seams and flanges and galvanized aftermanufacture, except where it forms part of a canopy when it is to be of stainlesssteel.

e. Stainless steel canopies are to be fitted over all equipments that are potentialsources of fumes and/or steam.

f. All canopies are to be fitted with condensate drains leading to the nearest deckdrain, saveall or sink and those fitted over ranges, frying and grillingequipments are to be provided with grease filters with portable drip trays.


March 2000

5.11

g. Exhaust trunks serving ranges, frying and grilling equipment are to be fittedwith fire flaps as detailed in Section 9. The air exhausted from these positions isto be a minimum of 30% of the total air�conditioning supply and is to bedischarged directly overboard.

h. Within the galley, supply air terminals are to be so positioned in relation toexhaust/recirculation terminals (See Clause 5.12.1jbelow) to prevent the escapeof odours and steam into the compartment.

i. The supply air is to be evenly distributed throughout the compartments, carebeing taken, when positioning terminals, to ensure that cooled air is notdirected on hot food at serving counters nor onto the heads of galley personnel.

j. Exhaust/recirculation terminals are to be positioned within the canopies andover other sources of heat, steam and odours, e.g. refrigerators, sinks,preparation areas, etc.

k. To prevent over cooling when galley equipment is not in use and in cold climatesthe heat extraction is to be regulated in accordance with Paras 5.6.aand 5.6.b,i.e. by:

(1) Controlling the flow of CW through the cooling coils by means of athermostatic, three�way, diverter valve;

(2) Reducing the air flow passing over the cooling coils by means of variablevolume fans;

(3) A combination of (1) and (2).

l. Acoustic insulation is not as a rule to be fitted in galley exhaust or recirculationtrunking, however should the achievement of noise target levels be impracticalthen it may be fitted if lined internally with a material suitable to facilitatesteam lance cleaning.

5.12.2 Pantries and Pantry/Serveries

a. These spaces are to be air�conditioned and treated similarly to galleys andsculleries. Wherever practicable they are to be grouped with a galley, serveryand scullery and served by a single system.

b. Where a pantry is sited remote from a galley it is to be supplied from an adjacentair�conditioning system, the exhaust being discharged directly overboard, via acompatible mechanical exhaust system, or returned to the ATU via a fullytrunked recirculation system.

c. Odour filters, grease filters, and fire flaps are to be fitted as appropriate.

5.12.3 Miscellaneous

a. Continuous flow steam emitting water heaters and boiling urns sited in dininghalls, etc., are to be provided with canopies and drains and ducted to the mostconvenient exhaust or trunked recirculation system.


5.12

5.13 Laundries and Associated Spaces

a. Laundries and associated spaces such as Finishing Rooms, Issue Rooms andReceipt Rooms are to be grouped and air�conditioned by a dedicated ATU with afully trunked distribution and fresh air system but with a partiallytrunked/open recirculation system.

b. Where air, heavily laden with moisture and lint, is vented from tumble dryers, itis not to be recirculated. Such air is to be discharged directly overboard by adedicated mechanical exhaust system that is controlled from within thelaundry and is protected by easily removable and cleanable lint filters sited asclose as possible to the drying tumblers. If sufficient air is available within therelevant fire/smoke zone a compensating natural supply will be taken from theship into the laundry unit room to balance the mechanical exhaust air quantity.If however there is not enough air available within the zone, in an `open ship'condition a natural supply make�up from weather is to be introduced into thelaundry to balance the exhaust air requirement. Where the AFU capacity will bepenalised in a `closed down' Alpha state, the tumbler dryers are not to beoperated.

c. The exhaust arrangements from the tumbler dryers is to incorporate a break inthe trunking, i.e. the mechanical exhaust system is to be branched down towithin approximately 150 mm of the tumbler drier exhaust spigot. Thisarrangement is necessary to enable the continuously operating laundry exhaustsystem to function when the tumbler dryers are not in use.

d. A negative pressure, relative to the surrounding spaces, is to be maintainedwithin all compartments of the laundry complex by ensuring that the negativepressure at the exhaust terminals is greater than the relative positive pressureat the supply terminals.

e. To enable the above systems to operate successfully in both `open ship' and`closed ship' states, supply and exhaust fans are to be interlocked so that theyoperate in tandem.

f. Cooled air is to be distributed evenly throughout the complex to ensure airmovement at all working positions. Recirculation/exhaust terminals are to bepositioned over equipments generating heat and steam.

g. In a `closed down' Alpha state the exhaust fan will have a change over systemwhich will recirculate air to the unit room instead of discharging it overboard, ifthe natural supply balance to the unit room is from the ship then this willbecome a natural supply to the ship balancing the fresh air supply quantity.However if a natural supply make up had been taken from weather, then it willbe secured and the system will continue to perform as described above.

5.14 Drying Rooms

a. The Drying Rooms provided for drying wet outdoor clothing(See NES 123 Part 1) are not in use continuously. Where possible they are to besited within machinery uptake spaces and special ventilation arrangements arenot required but if heated air systems are needed they are to conform with oneof the following configurations:

(1) Within the NBC Citadel (required to be used when `closed down'):


March 2000

5.13

(a) These spaces are to be served by a dedicated, inter�locked fan and airheater (i.e. the heater is not to be capable of operation unless the fanis running);

(b) 60�air changes per hour are to be provided, the fan taking a suctionfrom the crown of the compartment and discharging 80% of theintake back into the drying room via a heater. 20% of the intake is tobe passed through a condensing CW cooling coil located at aconvenient position to facilitate direct discharge back into thecitadel;

(c) Make�up air, equal to 20% of the fan total volume, is to be takenfrom the citadel through bulkhead grilles and returned to the fanintake via the exhaust/recirculation ducting;

(d) The heated air supply is to be arranged to discharge evenlythroughout the compartment under the hanging rails;

(e) The heater is to be controlled by a compartment type thermostatprovided as a control sensor to ensure that the space temperature ismaintained at 50°C;

(2) Outside of the NBC Citadel (not required when `closed down'):

(a) In these compartments the same system configuration is to be usedas that employed for drying rooms within the citadel except that the20% compensating make�up is drawn from atmosphere and the 20%bleed�off is discharged direct to atmosphere and not through a CWcondensing cooling coil back to the citadel.

5.15 Workshops

a. Workshops are to be air�conditioned with open recirculation back to the ATU.The fresh air requirement is to be trunked to the ATU.

b. The air�conditioning system is not to be used for dust extraction fromwoodworking machinery, etc., independent extraction systems are to beprovided.

c. Forges, welding bays, and any other sources of undesirable fumes withinworkshops are to be enclosed or fitted with canopies and exhausted direct toatmosphere. Make�up air is to be drawn into the ATU compartment from thecitadel and treated as a known leakage if there is a requirement to use thesebays when `closed down'.

d. Any special requirements deemed necessary to suit equipment located in or theoperational function of workshops are to be highlighted at the outset of thedesign with details clearly indicated in the ship specification.

e. The requirements of Clauses 5.6.aand 5.6.bare to be applied.


5.14

5.16 Sewage Treatment Spaces

a. These spaces, if located within the NBCD citadel, are to be air�conditioned witha closed circuit recirculation back to the ATU. A separate permanent exhaustsystem, equivalent to 15�air changes per hour, and discharging overboard is tobe provided in the event of a build�up of dangerous fumes or noxious gasesthrough leakage or maintenance. The discharge is to be protected with abutterfly valve which will normally remain closed. When operating thisexhaust system, air is to be drawn from within the citadel to balance thequantity lost and should be treated as a known controlled leakage whenassessing fresh air requirements.

b. If located outwith the NBCD citadel these spaces are to be mechanicallyventilated to meet the purging requirements of 15�air changes per hour and thesystem should comprise a balanced combination of fan exhaust and fan supply.

5.17 Storerooms

a. Storerooms which are in the Citadel are to be air�conditioned with openrecirculation back to the ATU with the exception of those designated hazardousspaces and cold and cool rooms, i.e. temperature controlled in accordance withNES 111. Any fresh air requirement is to be trunked to the ATU.

b. Storerooms designated hazardous spaces and located within the citadel are tobe air�conditioned and purged direct to atmosphere by a mechanical exhaustventilation system in an `open ship' condition and by citadel pressure vianon�return air bleed valves in a `closed down' Alpha condition.

c. The supply air is to be evenly distributed throughout the compartment. In theflour store air is to be delivered beneath the shelving or floor gratings.

d. To avoid the need to close down, deck stores which are outside the citadel are tobe supplied with air from the citadel and bled overboard. Where this places anunacceptable penalty on the number of AFU and valves required and there is norequirement for cooling, a mechanical supply with a mechanical or naturalexhaust system is to be provided to give 10�air changes per hour and heating to13°C. These openings are to be fitted with butterfly valves and be capable ofbeing closed from within the citadel (See Clause 11.8.e).

5.18 Conversion Machinery Rooms

a. These spaces are to air�conditioned by an ATU with a fully trunkeddistribution, fresh air and recirculation system.

b. Recirculation terminals are to be sited over equipments that provide a heatsource.

c. Cooled air is to be distributed evenly throughout the compartment withterminals being positioned to prevent hot spots forming in `dead' areas.

d. For greater control of compartment conditions, the cooling load on the centralATU may be assessed with minimum equipment operating in hot climates.Locally controlled CW unit coolers are then to be installed within thecompartment to provide extra cooling required when high heat sourceequipments are switched ON.


March 2000

5.15

5.19 Magazines

a. Ventilation and air�conditioning systems serving magazines are installed tomaintain the explosives in a serviceable condition and to provide acceptableconditions should men be working or stationed in the compartments.

b. Magazines containing weapons with liquid propellant or fuel, may requirespecial ventilation, drainage arrangements and fume detectors. As these arenot widely in use, these systems are not covered in this document but arecovered in NES 183 Part 1.

c. Arrangements are to provide for maintenance of watertight integrity,flash/flame tightness, anti�sabotage and NBCD requirements.

d. All magazines containing propellant are to be kept at a temperature below 32°C(27°C for Sea Wolf propellant and 29°C for Sea Dart propellant) in the hottestclimatic condition the ship is required to operate in. Compartments containingany other explosives or pyrotechnic stores, are to be maintained below 35°C tominimise chemical degradation. Where cooling is required to achieve thesetemperatures and a failure occurs, the temperature is not to rise above 40°C in12 hours and remain so for more than a further period of 12 hours. Alternativecooling is to be provided if this criteria cannot be met.

e. Heating will be required when calculations show that in Arctic conditions, theheat gain through structure is insufficient to maintain the internaltemperature of the magazine above 7°C.

f. Magazines are to be ventilated by a fully independent trunked distribution andrecirculation system, incorporating cooling and heating arrangements if thetemperatures specified cannot be met. In the majority of cases, these spaces willnot be continually manned for any length of time and a fresh air make�up willnot be necessary. Where the space could entail manning and the control of CO2

is necessary, fresh air make�up, via the AFU and bleed�off, is to be provided.

g. In the case of small ready�use upper deck magazines, Pyrotechnic, Small Armsmagazines, stores covered by the magazine regulations and those fitted inMinor War Vessels (MWV) which do not warrant a fully independent trunkedsystem, a supply from an adjacent ventilation system and exhausting overboardcan be considered. Such an arrangement must ensure that the boundary of themagazine is protected by watertight valves sited outside the magazine and theventilation supply is drawn from within the citadel (when fitted). This is to betreated as a known leakage area for AFU sizing. The requirements for heatingand cooling are applicable.

h. Ventilation systems to magazines are to be independent from any other shipventilation system. Where a shared system has been used, it is not to beconnected to a compartment with a high risk. Trunking is to be watertightoutside the magazine up to the junction of the shared system and a wire meshgrille fitted at this junction as an anti�sabotage precaution.

i. All ventilation openings to and from magazines, are to be capable of being madeflash/flame tight using watertight butterfly valves (magazine type) fitted to allventilation trunks where they enter or leave the compartment.


5.16

j. All magazine supply and exhaust ventilation valves are to be capable of beingoperated locally and remotely from within the citadel. The remote and localoperating positions are to be separated from each other by:

(1) A main watertight bulkhead or;

(2) At least two decks.

Where a vessel does not have a citadel, the local and remote operating positionsare to be separated as above.

k. Local and remote ventilation operating positions are to be readily accessible atall times and must not be sited in compartments which are normally locked, orlocated in positions within the compartment where the contents may restrictaccessibility.

l. The remote operating ventilation valve handwheel, if fitted is to be of thelockable type and locked open in peacetime. A disconnecting coupling pin is tobe fitted at the local operating position and is to be fitted with a padlock. Wherethe remote operating handwheel is not capable of being locked, it is to be sited ina lockable cabinet.

m. At each ventilation isolation position, a notice is to be fitted to adjacentstructure which identifies the system and the procedure necessary to isolate thecompartment. The notices are to be either permanent tallies or painted withred letters on a white background, minimum size is to be 150 mm high x 100 mmwide. Both local and remote notices are to carry the same wording.

n. In MWV where the above may not apply, a remote control position is to beapproved by the DA. As appropriate, this may require the termination of rodgearing or other control mechanisms from the valves into a lockable cabinet. Inthis arrangement, disconnecting couplings with padlocked pins, are to be fittedat the local positions.

o. Ventilation trunks are to be arranged to prevent the passage of articles into anycompartment containing explosives by fitting anti�sabotage devices.

p. Ventilation trunks are to be manufactured from galvanized mild steel. They areto be of watertight construction (to the same pressure as the compartmentthrough which they pass) over the whole of their length outside of the magazinethey serve. In vessels which are designed to meet low magnetic signatures, thetrunking is to be of non�magnetic material as approved by the DA. Inspection oraccess covers in trunking outside the magazine which it serves, are notpermitted. Portable sections of the trunking are to be arranged as necessary forcleaning purposes, these being secured by flanged joints. In compartmentswhere watertightness is not required for damage control purposes, the aboverule still applies except that the trunks are only required to be flash/flame tight.

q. Electrical equipment such as fans, heaters, air�conditioning units, coolers, etc.,are to be sited normally outside the magazine. Where unavoidably fitted inmagazines, electrical equipment is to comply with the requirements ofNES 519. Only approved electrical equipment listed in NES 593 is to beselected for fitting in magazines. In Naval Armament Vessels, when the supplyfan is sited on the weatherdeck, the fan motor is to be watertight.


March 2000

5.17

r. Trunking systems are to be arranged so that there is no interference with thespraying or ammunition handling arrangements.

s. Where additional heating is necessary, it is to be provided by ducted hot waterheaters or hot water radiators supplied from an electrical calorifier andthermostatically controlled. Direct electric heating should not be used if at allpossible. If hot water heating is not available, water from the domestic hotwater system may be used as the heating medium.

t. If heating cannot be provided using hot water, dispensation will have to besought from the DA to fit electric `in line' heaters within the trunk supply, butsited outside the magazines.

u. No alteration is to be made to the construction of the ventilation arrangementswithout the DA approval. Any departures must have Magazine SafetyCommittee approval and be recorded on SSCF 4 Forms.

5.20 Compartments Containing Dangerous or Noxious Gases

5.20.1 General Requirements

a. See Clause 2.7 for Local Exhaust Ventilation requirements.

b. As a general rule, these spaces are to be located outwith the NBCD citadel wherethey are to be ventilated by mechanical exhaust systems with either a natural ormechanical supply to balance the exhaust air quantity. If however thecompartment was to be located within the citadel, then in addition to themechanical exhaust ventilation the compartment is to be served by a dedicatedATU supplying an air quantity equal to that being extracted. In a `closed down'Alpha condition the exhaust fan will be switched off and the compartmentpurged to atmosphere via non return air bleed valves using citadel pressureWhere air flows are such that it is cost prohibitive to supply the fresh air via anAFU or add a dedicated ATU then a natural supply make�up is to be provided. Inthese circumstances both the natural supply and mechanical exhaust systemsare required to be shut down during a `closed down' condition and thecompartment secured until ventilation systems have been restarted and thecompartment has been purged. Closure of the ventilation system is to beachieved with butterfly valves capable of both local and remote operation fromthe Ship Control Centre (SCC). Machinery spaces are covered in Section 8.

c. Unless specified otherwise the air flow through these compartments is to besufficient to:

(1) limit the difference between compartment and weather ambienttemperature to 5°C;

or

(2) provide a minimum of 12�air changes per hour;

whichever is the greater.

d. When the compartments form part of the citadel and a dedicated ATU is to befitted, the fresh air requirements for these compartments are to be consideredas known controlled leakages from the relevant fire zones when calculatingAFU requirements.


5.18

e. Trunking is to be of gastight construction and fans are to be sited as close aspracticable to the ship's side.

f. No hand holes or inspection covers are to be fitted but portable trunk sectionsare to be provided for cleaning purposes.

g. Trunks are to be routed clear of spaces that are designated as a high fire risk.

h. Systems serving compartments that contain highly flammable materialsand/or explosive gases are to be provided with the following:

(1) Flameproof gauzes at the outboard end of mechanical exhaust systemsand at supply openings;

(2) Butterfly valves/fire closures fitted to the ventilation openings at theboundary of the compartments served;

(3) Centrifugal or bifurcated type fans with spark resistant features that aresited outside of the compartment;

(4) In extreme cases where it is essential that fans are installed inside thesecompartments, they are to be of the centrifugal type with flame andexplosion proof motors in addition to spark reducing features.

5.21 Refrigeration Machinery Compartments, Refrigeration Machinery and BottleStowages for Heavier than Air Gases

a. In conjunction with Clause 5.20, where applicable:

(1) 50% of the exhaust is to be taken from deck level (not more than 150 mmabove the deck) and 50% from the crown of the compartment at top ofstowage cabinet;

(2) Where air�conditioning/refrigeration is not installed in a dedicatedcompartment, it is to be provided with a dedicated exhaust system thatdischarges directly overboard. An air flow based on 0.1 m3/s per 100kW ofplant capacity, with a minimum flow of 0.05 m3/s, is to be provided and theexhaust terminals are to be sited as close as possible to the plant at decklevel;

(3) Where Bromotrifluoromethane (BTM) (Halon 1301) bottle stowages areprovided on the weatherdeck outside of the citadel, the provision ofnatural supply and exhaust arrangements, will be sufficient.

5.22 Battery Charging Rooms and Spaces Containing Battery Charging Facilities

a. In conjunction with Clause 5.20 and NES 101 Part 2, where applicable:

(1) All rooms, lockers and boxes for storage batteries, are to be arrangedand/or ventilated to avoid accumulation of flammable gas. Particularattention is to be given to the fact that the gas emitted is lighter than airand will tend to accumulate in any pockets at the top of the space. Whenbatteries are arranged in two or more tiers, all shelves are to have not lessthan 50 mm space front and back for circulation of air;


March 2000

5.19

(2) Exhaust terminals are to be sited over the sink (if fitted) at the top ofcompartments or canopies. Adequate openings, whether connected toducts or not, for air inlets, are to be provided near the floor of batteryrooms or the bottom of lockers or boxes;

(3) Exhaust is to be at least equal to:

Q = 110 � I � N where

Q = Litres air/hr

I = Max charging current in amps during gas formation

N = Number of cells

or to achieve the specified temperatures at Clause 5.20, whichever is thegreater.

(4) The inside of all canopies, trunking, fan casing and impeller, is to betreated as specified in NES 763;

(5) Acoustic insulation is not to be fitted in the trunking;

(6) Flameproof gauzes, spark resistant fans, butterfly valves, etc., are to befitted.

5.23 Paint Rooms, Paint Stores and Flammable Stores


(1) 50% of the exhaust is to be taken at deck level (not more than 150 mmabove the deck) and 50% taken at deckhead level;

(2) Flameproof gauzes, spark resistant fans, butterfly valves, etc., are to befitted.

5.24 Hydrogen and Acetylene Storage Compartments


(1) Where these stowages are within the citadel an air flow to satisfy aminimum requirement of 60�air changes per hour within thecompartment or cabinet is to be provided;

(2) The air is to be exhausted from high level only, due care being taken toeliminate any potential `dead spots' between deckhead beams, etc.;

(3) Flameproof gauzes, spark resistant fans, butterfly valves, etc., are to befitted;

(4) Where these stowages are on the weatherdeck, outside of the citadel, aventilation system need not be provided. Where the stowage is enclosedby a door, the door must be constructed of wire mesh or be fitted withlouvres over 75% of its area.


5.20

5.25 Compartments Containing Petroleum, Oils, Lubricants, etc.


(1) The following requirements are to be met when ventilatingcompartments, storerooms or stowages containing petroleums, oils,lubricants and other hazardous stores as classified in BR 1754:

(a) Stores that contain compressed flammable gases and/or liquefiedpetroleum gases:

(i) Flameproof gauzes, spark resistant fans and butterfly valvesare to be fitted as appropriate;

(ii) Fans are not to be installed inside these compartments underany circumstances;

(iii) The exhaust air is to be taken 50% from high and 50% fromlow level.

(b) For fuels, oils and stores classified as POL Class 1 (flash point below21°C) and POL Class 11 (flash point 21°C to 55°C):

(i) Flameproof gauzes, spark resistant fans and butterfly valvesare to be fitted as appropriate;

(ii) Centrifugal or bifurcated fans with spark resistant featuresare to be used and wherever possible must be sited outside ofthe compartment. If essential, spark resistant centrifugalfans with flame and explosion proof motors can be positionedwithin the compartment;

(iii) Exhaust is to be taken 50% from high and 50% from low levels;

(iv) 60�air changes per hour is to be provided.

(c) For fuels, oils and stores classified as POL Class 111 (flash point55°C to 100°C):

(i) Similar arrangements to those specified for POL Class 1 and11 stores are to be provided except that flameproof gauzes andbutterfly valves at the compartment boundaries are notrequired;

(ii) 12�air changes per hour is to be provided.

(d) Where a compartment contains a mixture of POL Class 1, 11 and111 stores, the more stringent requirements are to be implemented;

(e) Notices are to be posted at exhaust system discharges in accordancewith BR 1754.


March 2000

5.21

5.26 HP Air Compressors


(1) To ensure that breathing apparatus is always charged with clean,uncontaminated, smoke free air, the air supplies to HP compressors sitedwithin the NBCD citadel are to be trunked direct from the discharge sideof the AFU fan in the relevant fire zone;

5.27 Incinerator Compartments


(1) These compartments are sited outside of the NBCD citadel and are to beventilated by a mechanical supply and natural exhaust to atmosphereexcept when the incinerator incorporates its own combustion/ventilationfan;

(2) Where independent mechanical supply is required the air flow is to besufficient to provide a minimum of 12�air changes per hour within thecompartment;

(3) It is essential for the ventilation system to provide a positive pressure toprevent blow back during the lighting of the incinerator;

(4) The supply is to be concentrated at the operating/manned position;

(5) The natural exhaust opening is to be sited above the incinerator;

(6) Where access is provided between the incinerator compartment and theNBCD citadel it is to be protected by an Air Lock.

5.28 Hangars


(1) Hangars are outside of the NBCD citadel and are not generallyair�conditioned. These spaces are to be ventilated by a mechanicalexhaust system and a mechanical or natural supply;

(2) The air flow is to be sufficient to provide 5�air changes per hour or, in hotclimates, to keep the temperature rise to a maximum of 5°C aboveambient, whichever is the greater;

(3) Flameproof gauzes are to be provided as per Clause 5.20;

(4) Heating is to be provided by air heaters in the supply trunks, overheadradiant panels and/or unit heaters. In all cases the heating media is to bethermostatically controlled and wherever possible is to be hot water,supplied from an electric calorifier, or steam if available. Direct electricheating is only to be used when hot water or steam cannot be madeavailable and is to be restricted to electric fan unit heaters sited at a highlevel;

(5) Controls are to be fitted at supply and exhaust fans to enable the air flowto be reduced by 50%. The calculated heating load is to be based onmaintaining the compartment temperature at 13°C with 50% maximumair flow at the specified cold weather ambient temperature;


5.22

(6) Where diesel driven portable machinery is used in a hangar, provision is tobe made for the diesel exhaust to be connected into the hangar exhaustsystem by means of flexible trunk and a hose connection;

(7) In large hangars (e.g. those in aircraft carriers) the followingarrangements are to be implemented:

(a) Exhaust air is to be taken 40% from high level and 60% from lowlevel;

(b) Where heating is by air heaters in supply ducts a fan supplyequivalent to 80% of the total exhaust is to be provided, theremaining 20% being drawn, as a natural supply, direct fromatmosphere;

(c) The fan supply is to be distributed around the compartmentbulkheads with louvres or diffusers sited over working positions at aheight suitable for adjustment by personnel if possible;

(d) Where heating is by unit heaters and/or radiant panels positionedaround the hangar the total supply is to be taken, as a naturalsupply, direct from atmosphere;

(e) Natural supplies are to be positioned at a high level.

b. In small hangars (e.g. those in destroyers, frigates, etc.) the followingarrangements are to be implemented:

(1) Exhaust air is to be taken 20% from high level and 80% from low level;

(2) Heating is to be provided by radiant panels and unit heaters;

(3) A natural supply is to be provided at high level.

5.29 Vehicle Decks


(1) Vehicle decks are outside of the NBCD citadel and are not to beair�conditioned. These spaces are to be ventilated by a mechanicalexhaust system and a mechanical or natural supply;

(2) Calculation of the theoretical total airflow required in order to dilute thepolluted air to within the permitted occupational exposure limits inaccordance with ISO 9785 or 20�air changes per hour, whichever is thegreater;

(3) The types of engine in the vehicles, the engine size, operation cycles(activity on board) and the anticipated number of vehicles normally inoperation simultaneously in each working area, is to be obtained from theDA;

(4) Flameproof gauzes are to be fitted as per Clause 5.20;

(5) Heating is to be as for Clause 5.28.a.(4);

(6) Controls are to be as for Clause 5.28.a.(5) in working areas when vehiclesare not running;


March 2000

5.23

(7) Exhaust air is to be taken 40% from high level and 60% from low level;

(8) Where heating is by air heater in the supply trunks, a fan supplyequivalent to 80% of the total exhaust is to be provided, the remaining20% being drawn, as a natural, direct from atmosphere;

(9) The fan supply is to be distributed around the compartment bulkheadswith louvres or diffusers sited over working positions at a height suitablefor adjustment by personnel if possible;

(10) Where heating is by unit heaters, and/or radiant panels positioned aroundthe hangar, the total supply is to be taken as a natural supply, direct fromatmosphere.

b. Natural supplies are to be positioned at high level.

5.30 Electrical Switchboard Rooms

a. Electrical Switchboard Rooms which are located inside the citadel are to be aircooled to limit the compartment temperature rise to 10° C above the outsideambient. Recirculation air to balance the supply air quantity will be led back tothe ATU via terminals strategically situated above the heat producingequipment and thereby minimise heat dissipation into the compartment.

b. If the space is located outside the citadel a mechanical supply system is to beused to limit the compartment temperature rise to 10°C above the outsideambient with the additional proviso that it must not exceed 45°C. A balancingnatural exhaust quantity will be led direct to atmosphere via terminals situatedabove the heat producing equipment.

5.31 Emergency Generator Compartment

a. Unless otherwise specified this compartment is to be self ventilated, i.e. theradiator cooling fan for the generator and its complementary naturalventilation are used to provide the ventilation requirement.

5.32 Steering Gear (Secondary Steering Position)

a. This space is normally located outside the citadel and served by a mechanicalsupply and natural exhaust system. However, if it or part of it is to be used as asecondary steering position and has a separate compartment for this functionwhich is considered to be inside the citadel then this separate compartmentshould be air�conditioned with recirculation back to the relevant ATU.

5.33 Dry Provision Room

a. The air supply for this compartment is to be sufficient to maintain thetemperature between 10°C and 13°C with a relative humidity of no greaterthan 60%.

5.34 Air Balance Diagrams

a. It is essential that Air Balance Diagrams are prepared and continuouslyupdated for each NBCD/fire zone when air distribution systems are beingdesigned.


5.24

b. These diagrams, supported as necessary by tabular statements, are to show thatwithin each NBCD/fire zone:

(1) Fresh air intake is sufficient to:

(a) Compensate for known leakages, under all conditions;

(b) Generate the required over pressure in the fully `closed down' state;

(c) Replenish oxygen lost to respiration, combustion and otherprocesses thereby maintaining CO2 content below maximumpermitted levels.

(2) Pressure differentials between adjacent zones are maintained at amaximum of 0.5 mbars under all conditions and access between zones isnot jeopardised.

(3) Supply air routes to hazardous compartments within the NBCD citadelare unobstructed in all conditions.

c. Recirculation routes from air�conditioned compartments back to the ATU areidentified, feasible and remain unobstructed in all conditions.

d. Dangerous, toxic, undesirable air from hazardous compartments, machineryspaces, etc., will not contaminate the atmosphere in the citadel.


March 2000

6.1

6. COOLING SYSTEMSRelated Documents: NES 329, NES 341 Part 1, NES 345, NES 360, NES 501,NES 703, NES 710; see also Annex A.

6.1 General

a. CW systems provide the means for transferring heat from heat exchangers inweapons systems, electronic equipments and ATU situated throughout thevessel to CWP where the heat is extracted from the Fresh Water (FW) andtransferred overboard via the condenser cooling water.

6.2 Statement of Style

a. Two categories of CW systems will normally be included in any ship design:

(1) Essential Systems to supply CW to heat exchangers and ATU coolingcompartments and equipment which are classified as being essential toship's operational capability;

(2) Non Essential Systems to supply CW to ATU, unit coolers and heatexchangers cooling compartments and equipments which are classified asbeing non essential to ship's operational capability.

6.3 Design Principles

a. A reliable supply of cooling water at the correct temperature is essential for theoperation of weapons equipment and this aspect of the CW system must beafforded the highest priority throughout the design and installation process.

b. System design and installation is to be in accordance with NES 710 andelectrical cabinet cooling is to be in accordance with NES 501.

c. The system design is to be based on a constant volume of water being incirculation under all cooling conditions.

d. The design water inlet and outlet temperature at the CWP is to be 13.5°C and6.5°C respectively at the full cooling load conditions, i.e. the system and CWPevaporators are to be designed for a water temperature drop of 7 K at full load.

e. To ensure correct operation of the heat exchangers the CWP CW outlettemperature is to be controlled at 6.5°C ±1° C.

f. Adequate margins are to be allowed for through life growth and systemdegradation when selecting CWP and calculating pipe sizes. A growth margin,the magnitude of which will be specified in the project STR is to be allowed inexcess of the calculated cooling load of all essential and non�essential CWsystems for selection of the CWP.

g. CW pumps are to be selected to circulate a water volume 10% greater than thedesign CW flow through the CWP to which the pump is connected.

h. The selection of CWP and CW distribution system will depend upon the scaleand scope of the project and the following is for guidance purposes only:

(1) Essential systems are to be constrained within NBCD/smoke zones.Several essential systems may be included;

(2) Non essential systems may be a shipwide system or constrained to zonesspecified within the project Technical Equipment Specification (TES);


6.2

(3) Essential systems and non essential systems may be supplied from thesame CWP provided that arrangements are made for the essential systemusers to take precedence over the non essential system users duringperiods of routine maintenance or CWP failure (See Figure 6.2);

(4) A dry main is to be included for supply of water to essential users during inport periods when the CWP are not available if required by the projectTES;

(5) Each essential system is to be served by a discrete CWP if required by theproject TES. In this circumstance a plate type heat exchanger is to beincluded to enable cooling to be taken from the non essential CW system,in the event of plant breakdown without mixing of the water in the twosystems. In this condition the CW is to be supplied to essential systemusers at a temperature of 9°C ± 2°C. The plate heat exchanger is to bedesigned for the calculated essential system cooling load plus a growthmargin to be specified by the project TES. The pipework serving the plateheat exchanger is to be sized accordingly;

(6) Where essential systems are connected to discrete CWP no standby CWPis required for the non essential systems unless this is a requirement ofthe project TES for cooling of machinery spaces under `closed down'conditions (See Figure 6.2);

(7) Running and standby pumps are to be provided for each discrete essentialservices CWP. Non essential services CWP are to be provided with a singlediscrete CW pump;

(8) The pipework system is to be designed for a working pressure equal to thepressure head developed by the CW pump, plus the maximum static headof the system plus the expansion tank excess pressure. The completesystem, when installed is to be tested to a pressure of 150% of the designpressure calculated as above;

(9) CW system pipe velocities are to be between 2.5 m/s and 4.5 m/s for allsystems. The minimum pipe diameter is to be 16 mm.


March 2000

6.3

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Figure 6.2 – Discrete Essential Services CW System


March 2000

6.5

6.4 System Arrangement and Components

a. Each essential and non�essential system is to include:

(1) Shore connections to enable each system to be filled from outboardsources;

(2) Rapid refill hose connections to enable each system to be filled with FW orSea Water (SW) from within the ship using ship's pumps. Refilling of theessential systems from within the ship is not to exceed 20 minutes for anysingle system;

HEALTH AND SAFETY NOTE.

The connection between the CW and the Fresh Water system must include aflexible hose with instantaneous connections. System pipework (CW and theFresh Water) to be fitted with locked valves, the fresh water valve is to be aScrew Down Non�Return valve (SDNR).

(3) Expansion/Make�up Tank, continually pressurised to 1 bar abovemaximum static pressure of the particular system, and fitted with a lowlevel alarm and CW pump cut�out with battle `override'. When the excesspressure is created by introducing another liquid or gas into the tank theCW is to be isolated from the pressurising medium by means of animpervious, flexible membrane. The capacity of each tank is to be at least5% of the capacity of the system that it serves;

(4) Air Bleed Valves at all high points in each system;

(5) Air Collection Vessels;

(6) Drain Connections at low points to enable pipework and equipments to beemptied for repair or maintenance;

(7) Pressure Gauges at CW pump(s) suction and discharge;

(8) Flexible hoses and bellows fitted between rigid pipework and CWP, CWpumps, weapons cabinets and other shock/vibration mounted equipmentequipments. These connections are to be manufactured in accordancewith NES 345;

(9) Various valves to isolate, bypass and reconfigure systems and equipmentsas required. NES 360 provides guidance for the selection of valves;

(10) A 5 micron filter is to be installed in a bypass between the supply from theCWP(s) and the return to the CW pump(s). A quantity of CW equal to atleast 5% of the total flow required by the system users is to continuallypass through this filter;

(11) An injection quill NSN 0240/4820�99�918�3586, injection pumpNSN 0242/4320�99�831�2890 and sampling point is to be sited in aconvenient position so that biocides, anti�freeze and/or corrosioninhibitors, etc., can be added and samples can be collected to routinelymonitor the quality of the water;

(12) An electric flow measuring device at each main riser (not the venturitype), calibrated in litres/sec to an accuracy of ± 5% of the total flow.


6.6

b. Each heat exchanger or bank of heat exchangers is to be provided with a controlpanel which is to contain:

(1) Manual isolating and thermostatically operated threeway diverter valves,arranged to give either direct or bypass flow;

(2) A flow meter calibrated in litre/s to an accuracy of ± 5% of the total flow;

(3) A constant flow regulating valve;

(4) A 60 micron filter/strainer;

(5) The flow meter is to be positioned in the supply pipework and is to operatein both the direct flow and bypass configurations;

(6) The filter is to be positioned so that it straightens the flow to and protectsthe flow meter;

(7) Where a control panel serves one heat exchanger the constant flowregulator is to be fitted in the CW supply line and is to function in both thedirect flow and bypass configurations. Where the control panel serves abank of heat exchangers dedicated constant flow regulators are to befitted in the CW supply leads to each heat exchanger in addition to theconstant flow regulator in the control panel which, in these cases will besited in the bypass pipework;

(8) Constant flow regulating valves are never to be fitted in series, and arealways to be sited in accessible pipework;

(9) The constant flow device, the flow meter and the filter are to be capable ofbeing isolated for maintenance and replacement purposes, and wherepracticable a lockable bypass is to be fitted around these items to facilitatesystem flushing;

(10) To prevent condensation the control panel is to be fitted in a box andlagged externally. Pipework and fittings in the box are to be left unlaggedbut provision is to be made to collect and remove any condensation thatmay occur.

6.5 CW/Air Heat Exchangers (Coolers)

a. CW/Air Heat Exchangers are to conform with the requirements of NES 329.

b. Coolers are to be of the tube and plate fin type, tubes and fins being of tinnedcopper. The tubes can be spiralled, grooved or rifled to increase waterturbulence but internal turbulators are not to be employed for coolers likely tobe subject to shock accelerations.

c. In general coolers are to be positioned at the inlet of an appropriate fan anddesigned for CW temperatures of 6.5°C `ON' and 13.5°C `OFF' with the facearea of the cooler being based on an air velocity of 2.3 m/s. In special cases theair velocity may be increased up to a maximum of 3 m/s but moistureelimination arrangements must be provided to prevent carry�over ofcondensation.


March 2000

6.7

d. Each cooler is to be fitted with venting and drain plugs and provision is to bemade for the collection and removal of condensation. Where drains are fitted awater trap, sufficient in depth to ensure that the condensate will flow away, is tobe included.

e. Tubular elements are to be shop tested with air under water pressure of 18 barfor 15 mins with no evidence of leakage.

f. When selecting a cooler considerable care must be given to achieving humiditystandards, i.e. supply air must pass over sufficient tubular elements to ensurean adequate amount of moisture is extracted. This is especially important whenthe Sensible Heat Ratio (SHR) of the compartment(s) served indicates thepresence of a significant amount of latent heat.

g. In any class of vessel the range of coolers selected as an integral part of the CWsystem is to be restricted as much as possible in order to reduce spares holdings.

6.6 Materials

a. General CW System pipework is to be 90/10 cupro nickel. The evaporator shell,of shell and tube type evaporators, is to be 90/10 cupro nickel.

b. All other components in the system in contact with the water are to be nonferrous.

c. Maximum use is to be made of brazed and welded fittings with connecting jointsbeing used only for removable section of pipe and for valves, etc. On no accountis any carbon steel to be incorporated into the system.

6.7 Cleanliness

a. All pipes and fittings are to be cleaned after manufacture and before installationin ship. Systems are to be fitted to the cleanliness standard grade C as defined inNES 341 Part 1.

b. On completion of the installation of each system all obstructions within thepipework such as filters, constant flow diaphragms, etc., are to be removed or, ifpossible, the control panels are to be by�passed. The pipework is then to beflushed with clean mains water and drained. The system is then to be filled withwater of the specified quality and a 40 micron filter and pump fitted. The pumpis to be capable of continuously circulating the water at a minimum velocity of3 m/s through the system, including cooling coils, for at least 24 hours, the filterbeing replaced or cleaned as necessary. The water temperature is to be allowedto rise to a maximum of 38°C, and the flushing is to continue until the filterremains clean. The pump and filter are then to be disconnected and thenecessary diaphragms, filters, etc., replaced without the system being draineddown. Whenever a system is drained the complete flushing and fillingprocedure is to be repeated. Where diaphragms are removed from constant flowregulators care must be exercised to ensure that they are replaced in the sameorifice from which they were taken. In this type of fitting it is usual for thediaphragm and orifice to be a matched pair.


6.8

6.8 Water Quality

a. For filling, flushing and topping up systems, water of the following quality mustbe used:

(1) Conductivity Max 30 mS/cm;

(2) pH 5.5 � 8.0;

(3) Chlorides (as Cl) Max 5.0 mg/litre;

(4) Appearance Clear colourless and having no visible suspended matter;

(5) Total Hardness Max 5.0 mg/litre.

b. COOLTREAT 651 (nitrite) NSN 0473/6850�99�075�5214 is to be added at a rateof 5 litres per 1,000 litres of system capacity. This will equate to a nitrite systemconcentration of approximately 1200 mg/litre when adequately mixed.MICROTREAT 2200 (biocide) NSN 0473/6850�99�147�0707 is to beimmediately added after dosing with COOLTREAT at 2.5 litres per 1,000 litresof system capacity.

c. Once the system has been treated, three monthly laboratory testing is to beundertaken by the shipbuilder/repairer and the quality of the water maintainedas:

(1) Conductivity Less than 6,000 mS/cm;

(2) pH 9.5 � 11.0;

(3) Chlorides (as Cl) Less than 50 mg/litre;

(4) Suspended solids Slight, just visible (20 mg/litre);

(5) Total Hardness Max 100 ppm (CaCO3);

(6) Nitrite (NaNO2) Absolute minimum 900 mg/litre, Optimum 1200 � 1800 mg/litre;

(7) Bacteria (Dipslide) Less than 105 Colony Forming Unit (CFU)/ml;

(8) Dissolved iron (as Fe) Less than 10 mg/litre.

d. Monthly monitoring of the system using Water Testing KitNSN 0473/6665�99�765�4489 is to be carried out to record the followingminimum requirement:

(1) Nitrite levels Absolute minimum of 900 mg/litre, NaNO2 Optimum 1200 � 1800 mg/litre;

(2) Suspended solids Slight just visible; (Visual check only)

(3) Bacteria (dipslide) Less than 105 CFU/ml.


March 2000

6.9

e. It is imperative that nitrite levels never fall below the absolute minimum of900mg/litre. Deterioration of the system will occur below this level, even withina limited time period. Addition of nitrite inhibitor (COOLTREAT 651) is to beat the minimum rate of 5 litres per 1,000 litres. Should nitrite reduction beevident and presuming there is no ongoing physical leak from the system,bacteriological activity must be counteracted by the addition of MICROTREAT2200 at the rate of 2.5 litres per 1,000 litres. If loss of nitrite persists, presuminglittle or no system water losses, redose MICROTREAT 2200 at the rate of2.5 litres per 1,000 litres and monitor weekly as dictated by the results.

f. The periodicity of the uninhibited and inhibited system checks for ships inservice and method are as laid down in the Fleet Standard, Care of Treated CWSystems.

6.9 Compartment Cooling

a. Air, used to extract heat from air�conditioned compartments, is to be cooled byone, or a combination, of the following methods:

(1) ATU;

(2) CW Unit Coolers;

(3) Free Standing Air�conditioning Units.

6.10 Air Treatment Units

a. Cooling is to be by the air/CW heat exchanger that is an integral part of eachATU package. Details of ATU are given in Section 5.

6.11 CW Unit Coolers

a. This term is applied to small, self contained, units that consist of a fan, CWcooling coil, condensate tray and drain, and heating element, the fan andheating element being provided with local ON/OFF control. They require asupply of CW, electric power and drain connections.

b. Because of their vulnerability the use of these units is restricted tonon�essential compartments only.

c. Units are to be fitted in the compartments served, the air/recirculation inletbeing protected by a filter and the air/supply outlet being open or, if the fanallows, connected to a short length of local trunking.

d. The design and manufacture of these units to `good commercial marinestandards' is acceptable on condition that:

(1) The maximum noise levels, appropriate to the compartments served, arenot exceeded;

(2) The unit is engineered to ensure that condensation cannot migrate intothe compartment even when the ship is subjected to maximum angles ofroll, heel and pitch.


6.10

e. Generally CW unit coolers are to be used in non�essential compartments remotefrom central ATU that have insufficient heat load to justify fitting a dedicatedcompartment ATU. They can also be used in combination with central orcompartment non�essential ATU to give greater flexibility and control of singlecompartment conditions where high fluctuations in cooling loads can occur.

f. Where these units provide the total cooling within a compartment the selectionof the size type and number required is to take into account the need forhumidity control, including reheat, as well as the extraction of wild heat.

g. CW supply and return connections to a unit, or to several units within onecompartment, are to be via a control panel containing the necessary valves andfittings.

6.12 Free Standing Air-conditioning Units

a. Where a sufficient supply of CW is not available, MOD approved, free standing,self�contained, air�conditioning units may be used to cool specificcompartments. It is emphasised that recourse to this type of unit is only to be inthe most exceptional circumstances, especially in the initial ship design.

6.13 Equipment Cooling

a. The cooling systems for electric and electronic equipments are theresponsibility of the equipment designers and sponsors and are to be inaccordance with NES 501, i.e. cooling is to be achieved by either:

(1) Natural Cooling;

(2) Forced Air Cooling;

(3) CW Cooling.

b. Where natural cooling is used the heat generated by the equipment will bedispersed within the containing compartment and is to be treated as a load onthe appropriate ATU.

c. Forced air cooling can be achieved by either a fully closed or semi�closed system.Where a fully closed system is used, it is to be considered as the secondarycooling system, the primary system being CW serving a dedicated heatexchanger usually sited within the equipment cabinet. A semi�closed systemmay be served by a dedicated heat exchanger, sited outside of the cabinet, ortreated as part of the total load on the appropriate ATU.

d. Air cooling to and/or from equipment cabinets is to be via ducts, flexibleconnections and ventilation boxes incorporating orifice plates and fire�flaps.The fire�flaps are to be capable of being activated both remotely and locally.

e. CW can either be used directly to cool cabinets or in association with asecondary tepid water system.


March 2000

6.11

f. A flow switch that will give both audible and visual warning of reduced CW flowis to be fitted in pipework serving direct cooled weapons equipments. Where abank of cabinets is supplied, only one flow switch is required unless the highestflow rate to a single cabinet is in excess of four times the lowest flow rate, inwhich case additional flow switch(es) must be fitted. These switches are to beactivated when the actual flow drops to below 66% of the design flow, an audiblewarning being sounded locally and a visual warning being relayed to theOperations Room or SCC.

6.14 Demarcation

a. This NES covers the requirements for the continuous supply of CW, at specifiedtemperatures and flow rates, to the CW terminations at the cabinet(s)boundaries or to the connection points at dedicated heat exchangers, asappropriate. It also covers the supply and removal of sufficient quantities ofcooled air via ATU when the heat generated by the equipment is treated as partof the total air�conditioning load. All secondary and/or back�up systems,whether liquid or air are the responsibility of the Sponsor for the NES whichcover that particular equipment or system.

6.15 Dehumidifiers and Condensation Control

a. The RH levels in individual compartments are to be maintained betweenspecific upper and lower limits (See Section 4), and in hot climates the upperlimit is, generally, to be achieved by the removal of moisture from the air at themulti�element cooling coils which form an integral part of the ATU and whichare to be designed to cater for a wide range of SHR. For compartments wherethe SHR is below 0.5 the use of local reheat to reduce compartment RH, isacceptable.

b. The SHR of the compartments selected to be served by a single ATU are to liewithin the narrowest, practicable range but, because of the restrictions placedupon compartment grouping, considerable variation in the SHR ofcompartments within a group may be unavoidable. In this circumstance theselection of a cooler based upon the average or group SHR will not alwaysprovide a satisfactory solution for all compartments in extreme conditions andcalculations are to be carried out to identify spaces where high RH and localcondensation may become a problem. In such cases, if local reheat is not anappropriate solution, consideration is to be given to fitting localdehumidification units, bathrooms being a possible example.

c. When required, dehumidifiers are to be selected from available commercialranges that are designed and manufactured to `good commercial marinestandards' care being taken to ensure that the noise levels appropriate to thecompartment(s) concerned are not exceeded and the dehumidifier is engineeredto retain and drain condensation in even the most severe ship attitudes.

6.16 Insulation

Insulation of the CW System is covered by NES 703.

6.17 System Reliability

In general the CWP will be designed for a Mean Time Between Failure (MTBF) of 10,000 hrs and a Mean Time to Repair (MTTR) of 4 hrs. The CW System (ex plants) isto be designed for a MTBF of not less than 2,000 hrs and a MTTR of not more than 20minutes. The equipment reliability is to be as specified in NES 501.


6.12


March 2000

7.1

7. HEATING SYSTEMS

Related Documents: NES 329, NES 360, NES 529 Part 2, NES 596, NES 728, STR 422/04/08/231a; see also Annex A.


a. Heating systems are required in ships to maintain minimum dry bulbtemperatures within compartments at 22°C or 13°C, depending on the positionand function of the compartment, when the outside ambient is either:

(1) Arctic -29°C;

(2) Subarctic -10°C;

(3) Temperate Winter -4°C.

b. In all cases the relative humidity is not to fall below 30%. In accommodationand manned spaces it is generally to be maintained at 45% and only inexceptional circumstances is it to be allowed to fall below this figure and thenonly for a very limited time.

c. The preferred method of heating is by trunk mounted heaters and the mediumis normally, to be electricity but in certain spaces, there could be a build up offlammable or explosive gaseous mixtures where, hot water is to be used. Ifavailable, steam can also be considered as an alternative to either electric or hotwater.

d. As a general rule all trunk mounted heaters are to be automatically controlledby thermostat or sensor but in exceptional circumstances manual control maybe acceptable.

e. The ranges of electric and hot water heaters, both space and trunk mounted,selected for installation in any particular class of vessel are to be restricted as faras is practicable in the interest of interchangeability and to limit storesholdings.

7.2 Air-conditioned Compartments

a. When calculating the heating loads for air-conditioned compartments noaccount is to be taken of the heat gained from personnel or from adjacentcompartments unless the adjacent compartment is at a higher controlledtemperature, but heat losses to adjacent compartments and to atmosphere andwild heat gains from equipments are to be considered. In compartments wherefitted equipments may be shut off for significant periods the installed heating isto cater for this state.

b. These spaces are to be maintained at the DB temperature specified, generally bythe use of trunk mounted electric heaters. Where a single heater is fitted toserve more than one compartment the difference in the design supply airtemperatures over all the compartments served is not to be greater than 3°C.


7.2

c. Within a grouped system, compartments will require different supply airtemperatures and it is likely that several heaters of differing outputs will berequired. Where appropriate, consideration is to be given to reducing the sizeand/or number of trunked heaters by satisfying the highest compartment heat

loads with a combination of trunked and space heating. All air-conditionedspaces, where required, are to receive a heated supply and are not to bedependant on heating solely from recirculated air. Arrangements to reduce theCW and air flow in cold ambients are as specified in Section 5.

7.3 Hazardous Compartments Within the NBC Citadel

a. These spaces, where unmanned, are to be maintained at a minimum DBtemperature of 13°C. Where they are likely to be manned for significant periodsa minimum dry bulb temperature of 22°C is to be maintained.

b. When sizing and siting heaters in these compartments due regard must be givento the properties of any gases, vapours and stores contained or produced within

the space to ensure local `hot-spots' do not generate temperatures in excess ofthe relevant flash points.

7.4 Fresh Air

a. Fresh air trunked direct to ATU, whether from AFU or from weather inlets forATU sited outwith the citadel, is to be preheated to 5°C.

b. Fresh air trunked direct to compartments or to spaces within the citadel is to becapable of being heated to 13°C or 22°C as appropriate.

c. To reduce the risk of freezing and/or condensation, heaters are to be sited asclose as possible to the fresh air weather inlets.

7.5 Compartments Outside the NBC Citadel (Ex Machinery Spaces)

a. These compartments are to be maintained at a minimum DB temperature of13°C or 22°C as appropriate, by the use of trunk mounted and/or space heaters,unless the materials contained and the functions carried out in thecompartment dictate that heating is not required.

b. Where these compartments are supplied by a mechanical system and there areno specified minimum air change requirements for dilution rates etc., thenarrangements are to be provided to reduce the air flow by 50% or to theminimum required by personnel whichever is the greater, when in the heatingmode. No reduction in airflow is to be employed in dangerous/hazardouscompartments or where a specified minimum air change is required.

7.6 Classification of Heaters

a. Heaters are to be identified by their function, viz:

(1) Pre�Heaters:

These are trunk mounted heaters fitted in fresh air systems to raise thetemperature of incoming air before it enters the ATU to reduce the risk ofcondensation and protect coolers from freezing up in cold weather;

(2) Main Heaters:

These are:


March 2000

7.3

(a) Trunked mounted heaters that heat the mixture of fresh andrecirculated air to a suitable temperature for supplying the majorityof compartments in a grouped air�conditioning system. They areusually to be fitted on the main discharge trunks of a central ATUand where possible are sized to suit the standard 1 kW to 10 kWrange, thus minimising spares (See Clause 7.5);

(b) Any single trunk mounted heater that totally controls thetemperature of the supply air within a system;

(c) Any single trunk mounted heater that totally controls thetemperature of the air supplied to a compartment or group ofcompartments.

7.6.1 Supplementary/Boost Heaters

These can be either trunk mounted or space heaters. They are installed when acompartment or group of compartments require heating additional to that providedby pre and main heaters.

7.6.2 Reheaters

These are trunk mounted heaters fitted in air�conditioning supply trunks when SHRand calculations indicate that, in warm climates, the cooled air requires reheatingbefore being delivered to compartment(s) to ensure relative humidity levels are keptwithin acceptable limits.

7.7 Heater Controls

7.7.1 Positioning of Sensors

a. As a general rule all trunk mounted heaters are to be automatically controlledby thermostats or sensors which should be sited as follows:

(1) Pre�Heaters:

Sensor to be sited approximately one metre downstream of heater;

(2) Main Heaters of ATU:

Sensor to be sited clear of fresh air inlet in recirculation trunk, wherefitted, or in recirculation air stream;

(3) Single Main Heater Controlling Total System:

Sensor preferably to be sited in the recirculation trunk, if fitted and if not,in the compartment served or in a representative compartment when theheater serves a group. Care being taken to site sensor in a locationrepresentative of mean compartment temperature;

(4) Single Main Heater with Total Compartment Control:


(5) Supplementary/Boost Heaters:



7.4

(6) Reheaters:

Sensor to be sited approximately one metre downstream of heater.

b. Compartment sensors are to be sited in positions free of local heat sources andprotected from draughts.

c. Trunk mounted sensors are to be easily accessible for inspection andmaintenance.

d. A preferred range of sensors/thermostats for use with trunk mounted electricheaters is indicated in NES 596.

7.8 Electric Heater Controls

a. Thermostatic control of trunk mounted electric heaters is to be ON/OFFcontrol in those compartments where close temperature control is not essential,e.g. stores, workshops and unmanned compartments.

b. In accommodation spaces, offices, operational spaces, etc., proportional controlvia a control panel and strategically placed sensors is to be provided to ensure asteady maintained temperature to within ± 2°C.

c. Where it is not practical to fit proportional controllers multi�element heaterswith stepped ON/OFF switching are to be fitted. In this case only one elementneeds to be thermostatically controlled the other being switched manually.

d. In addition to thermostatic controls all trunk mounted electric heaters are tobe:

(1) Fitted with a safety cut�out at 100°C for each element, with a hand resetin the terminal enclosure. The resetting should not entail having todismantle the enclosure;

(2) Interlocked with the appropriate fan starter so that heater is notoperational unless the fan is running and element temperature will notrise to `cut�out' if fan is stopped;

(3) Provided with a seClause te ON/OFF switch;

(4) Fitted with a high temperature trip remote indicator, sited in aconvenient, manned compartment.

e. Electric space heaters in manned compartments are to be manually controlledby an ON/OFF switch or, where more than one element is fitted, by steppedswitching. In unmanned spaces a manual ON/OFF switch and a hightemperature cut�out with a remote trip indicator, sited in a convenient mannedcompartment, is to be provided.

7.9 Hot Water Heater Controls

a. Trunk mounted hot water heaters are to be controlled by two way/three way,direct acting, self operated, thermostatic valves that are activated by sensorssited in the compartment being served or in the recirculation trunk from thatcompartment.


March 2000

7.5

b. Hot water space heaters in manned compartments are to be controlled bymanually operated throttling valves but in unmanned compartmentsthermostatic control is to be provided.

7.10 Trunk Mounted Heaters

7.10.1 Electric Heaters

a. These heaters are to be generally in accordance with Statement ofRequirements. Electric Heaters for air�conditioning and ventilation in HMSurface Ships, STR 422/04/08/231a, but based on the preferred heatingelements specified in NES 529 Part 2. Where publications and specificationsreferred to in the STR have been superseded by NES 529 Part 2 the most recentrequirement is to be complied with.

a. The air/hot water heat exchangers are to conform with the requirments of NES 329 and consist of closely nested finned tubes, through which hot water iscirculated, enclosed in a suitable casing that will ensure the air to be heated willpass closely over the tube surfaces.

b. Tubes and fins are to be of copper and can be of any configuration that will givethe most efficient performance subject to the air side not becomingprogressively contaminated/obstructed by airborne dust and dirt.

c. The casing is to be of mild steel, galvanized after manufacture, and if requiredfor shock protection, suitably stiffened to ensure that the complete unit willwithstand, without damage or degradation in performance, the specified shockrequirements.

d. The tubes are to be capable of withstanding an internal pressure of 18 bar for 15minutes without any visible signs of leakage.

e. The total unit is to be attached to the ventilation/air�conditioning trunking in amanner that will allow it to be easily removed and replaced for maintenance andrepair purposes.

f. Each hot water heater is to be provided with facilities for venting and draining.

7.11 Space Heating

a. Space heating is to be limited to the following applications:

(1) Category 1

In compartments where the calculated temperature of the air supplied by theventilation would need to exceed 32°C. Space heater numbers and duties are tobe based on the difference between the required compartment temperature andthe maximum air flow temperature of 32°C;

(2) Category 2

In compartments that are on a common air�conditioning/ventilation systembut where heating requirements vary considerably. The main heater duty is tobe based on supplying air at 3°C above that required by the warmestcompartment and space heaters are to be provided as necessary to maintain thecooler compartments at the specified temperatures;


7.6

(3) Category 3

In compartments where heating is required but where the ventilation airsupply is natural or induced by a mechanical exhaust system.

7.11.1 Types of Space Heaters

a. The selection of a space heater to perform a specific duty is to be made from thefollowing types and will depend upon the materials stored and/or the processescarried out within the compartment to be served.

(1) Electric Heater Panels

These are to be of the non�luminous type and are to comply with the preferredrange specified in NES 596. These are not to be used in compartmentscontaining flammable stores or where there could be a build up ofdangerous/explosive gases.

(2) Fan Assisted Electric Heaters

These are to be used where a directional flow of air is required (e.g. above hangardoors to provide a curtain of warm air as protection when doors are opened) inCategory 3 compartments. They are not to be used in the hangar at low level orin other compartments containing flammable stores or where there could be abuild up of dangerous/explosive gases. Suitable fan assisted electric heatersdesigned and manufactured to `good commercial marine standards'appropriate to the duty required can be fitted with the proviso that noise levelswithin the compartment are not to exceed the maximum permitted.

(3) Hot Water Radiators

These are to be used where electric space heaters are prohibited. They are to beselected from available commercial ranges that are designed and manufacturedto `good commercial marine standards'.

7.12 Hot Water Systems

a. Hot water is to be used for heating spaces where electric heaters would beunacceptable, e.g. magazines, hangars, flammable stores, etc. It is to beprovided by closed circuit, hot water system(s) derived from an electriccalorifier(s) sited clear of all hazardous spaces and sized to suit the hot waterheating load(s) within the particular NBCD/fire zone.

b. Each hot water system is to be dictated by the disposition of the spacesrequiring hot water heating.

c. Hot water systems are to comply, where appropriate, with the specifications andstandards given in NES 728 subject to the following being included in eachclosed circuit:

(1) Expansion tank pressurized to 0.35 bar above system static pressure andfitted with a low level alarm and pressure indicator;

(2) Two pumps, one running and one standby, each protected by a strainer orfilter and integrated into circuit pipework with flexible connections;

(3) A calorifier with electric heating unit and controls generally inaccordance with NES 329. An engraved brass plate showing the design`ON' and `OFF' water temperatures is to be attached to the calorifier;


March 2000

7.7

(4) One or more air/hot water heat exchangers, (space or trunk mounted)each protected with a strainer and where required fitted withthermostatic control;

(5) Ball or SDNR valves to isolate each item of equipment and each branch ofpipework. These items are to be selected from NES 360;

(6) A dosing pot to allow the inclusion of descalers, inhibitors, etc., as andwhen required;

(7) Filling connections, drains and air relief valves are to be fitted as requiredthroughout the system;

(8) Where necessary, to relieve pressure under light load, a pressure reliefbypass, controlled by an orifice plate, is to be fitted around the pumps.

d. Expansion tanks are to be topped up and systems are to be filled, via suitableconnections, from the ship's fresh water system using ship pumps.

e. Pressurized systems that can operate at temperatures in excess of 100°C may beinstalled, after obtaining MOD approval, if it can be demonstrated that suchproposals will lead to significant savings in weight, space and cost.

7.13 Heater Markings

a. All heaters are to carry a brass plate engraved with the following information:

(1) Name of manufacturer;

(2) MOD/NATO serial number;

(3) Heater classification, i.e. pre�heater, main heater, etc.;

(4) Heater duty in kW;

(5) List of compartments/ATU served;

(6) Position of thermostat and control panel if fitted.

7.14 Humidifiers

a. Where calculations show that, in cold weather conditions, the humidity in air�conditioned compartments is likely to fall below the minimum acceptablelevel, humidifiers are to be introduced into the system (See Clause 4.4.a).

b. Humidifiers are to be the `Dry Steam Injection' type and on no account is the`Spinning Disc', or any other type that introduces atomized water direct intothe air stream or into the compartment atmosphere, to be used.

c. Each humidifier is to be controlled by:

(1) A humidistat placed in the air stream, that supplies the compartment(s)where low humidity levels are indicated;

(2) An interlock with the ATU fan starter to prevent operation unless the fanis running;

(3) A local ON/OFF switch will override the humidistat.


7.8


March 2000

8.1

8. MACHINERY SPACES

8.1 System Design

8.1.1 Cruise State/Open Ship Condition

a. In the `open ship' condition machinery spaces are to be ventilated bymechanical supply and mechanical exhaust systems.

b. The fan supply air quantity is to be calculated to restrict the rise in airtemperature between supply and exhaust to 15°C in hot ambient conditions,e.g. when based on an outside ambient of 30°C:

(1) Maximum wild heat is generated, with all essential equipment operatingsimultaneously at full power with space temperature maintained at 45°C;

(2) Structural heat gains/losses are calculated assuming:

(a) Temperature in upper half of space is 45°C;

(b) Temperature in lower half of space is 35°C.

c. To take account of the temperature rise and change in air density so as toendeavour to arrange a neutral pressure within the machinery compartment,the fan exhaust is to be taken as 107% of the fan supply. For compartmentscontaining main boilers and associated steam driven auxiliary machinery orsteam turbine machinery, the fan exhaust is to be taken as 115% of the fansupply to allow for both temperature rise and moisture pick�up.

d. To limit heat build up within these spaces, surfaces with temperatures in excessof 45°C are to be insulated but ship sides, especially that portion below thewaterline, are not to be insulated unless some exceptional overriding reasondictates otherwise.

e. All distribution and exhaust trunking in machinery spaces is to be of mild steel,galvanized after manufacture. Aluminium trunking is not to be used except invessels with restricted magnetic signature.

8.1.2 Action State/Closed Down Condition

a. Machinery spaces, for vessels that are designed to operate in hostile zones, arenot considered to be within the NBCD citadel and are not to be air�conditionedbut in the `closed down' condition they are to be:

(1) Cooled sufficiently to allow continuous operation for specified machineryoperating levels and for a specified time;

(2) Pressurised to prevent contamination by NBC agents.

8.2 Cooling

a. The ventilation system, if required for NBCD closedown, is to be capable ofbeing reconfigured into a recirculation system whereby, the supply air is routedover air/CW heat exchangers before being distributed throughout thecompartment and returned to the fan. In this configuration the machineryspaces are to be isolated from the external atmosphere and in general also fromthe NBCD citadel (See Clause 4.6.2).


8.2

b. The heat exchangers are to be sized to ensure that when `closed down',operating at full power, with essential machinery items runningsimultaneously, the maximum temperature within the space will not exceed65°C DB for equipment and 38°C WB for personnel. It is essential that heat isnot allowed to build up in isolated `hot spots' with the possibility of damagingelectric cables, etc., and the siting of distribution terminals is therefore critical.

c. CW is to be supplied to the heat exchangers in these spaces only when required.It is to be taken from the non�essential CW System and the additional heat loadbeing borne by the standby CWP and pump supported, if necessary, bysacrificing the least essential compartments.

8.3 Pressurization

a. In the `closed down' condition when isolated from outside atmosphere and fromthe NBCD citadel, the machinery spaces are to be capable of being pressurizedto approximately 3 mbar above atmospheric pressure, i.e. 2 mbar belowminimum citadel pressure.

b. A quantity of fresh air sufficient to cope with all known leakages and to generatethe required pressures is to be delivered to the machinery spaces via dedicatedNBCD filters which, being operated only during the `closed down' condition,will not require a bypass to be fitted. In exceptional circumstances a bleed�offarrangement from the citadel may be acceptable in lieu of dedicated AFU (SeeClause 4.6.2).

c. To ensure that the pressure within the machinery spaces does not exceed that inthe NBCD citadel, non return bleed valves, set to open at 3 mbar aboveatmospheric pressure are to be fitted. These valves will be set to pass thebalance between the AFU supply air quantity and the combined controlledlosses, if any, and the calculated uncontrolled losses from the machinery space.The method used for calculating uncontrolled losses is described in Clause4.6.2.

8.4 Air Systems

a. Supply:

(1) Supply trunking is to be arranged to give a general distributionthroughout the space with concentrations at major heat sources such asturbines, generators, uptakes, etc., to ensure the dissipation of heat frompotential hot spots;

(2) A quantity of supply air, not less than 0.03 m3/s/man, is to be delivered tothe emergency watch�keeping position via terminals that can control boththe direction and the amount of the air delivered;

(3) Where appropriate, supply outlets on large branch trunks are to be fittedwith adjustable vane terminals to give a limited control of air dischargevelocity and direction but for relatively low air volumes, in smallbranches, supply outlets are to be fitted with drum type louvres, slottedgrilles or bellmouths;

(4) Hose connections are to be fitted as necessary in the supply trunking topermit emergency ventilation of hot positions where personnel may haveto work for short periods;


March 2000

8.3

(5) Where two separate weather intakes serve a single compartment they areto be sited on opposite sides of the ship if possible.

b. Exhaust:

(1) Exhaust trunking within the machinery spaces is to be kept as short aspracticable, the terminals being sited at the deckhead over the principlesource(s) of heat;

(2) Where convenient the exhaust can be discharged into the uptake spacesbut care is to be taken that adequate clear area is provided at the outletfrom the funnel casing where the velocity is not to exceed 5 m/s. Where itis not possible to route the exhaust through the funnel casing, thedischarge terminal is to be sited as high as possible on the superstructureand well clear of any supply intakes, especially those downwind;

(3) Where a refrigeration or CWP is fitted in a machinery space it is to beserved by a dedicated low level exhaust system that discharges directlyoverboard or overboard via the main exhaust system. The flow rateprovided is to be 0.1 m3/s per 100 kW of plant capacity with a minimum of0.05 m3/s and is to be treated as a known leakage when assessing NBCDfilter numbers.

8.5 General

a. Weatherdeck inlets and outlets are to be fitted with internal closures whichhave a local and remote operating facility from the SCC to facilitate bringingthe ship to condition Alpha. Where the size, weight and cost penalties precludethis, the weatherdeck openings are to be fitted with Quick Acting HingedWatertight Covers (QAHWC). All weatherdeck inlets and outlets are to be madeself draining and fitted with spray eliminators and grilles.

b. A notice is to be mounted adjacent to each weatherdeck opening, or at theremote operating position, stating that the ventilation must be closed in theevent of fire in the machinery space.

c. In addition to a remote `crash stopping' facility sited in the SCC or at the mainswitchboard, machinery space fans are to be provided with an emergency shutdown position outside of the compartment adjacent to the firedrenching/smothering control cabinet.

d. Care is to be taken to ensure that short circuits between supply and exhaustterminals cannot occur.

8.6 Heating

a. Arrangements are to be provided to give the capability to reduce air flows by50% in cold weather.

b. The machinery spaces are to be provided with heaters either space or trunkmounted, that can, in cold weather, maintain a compartment temperature of10°C for maintenance uses when the machinery is not operational. Heatselection is to be based on the ventilation system being configured in therecirculation mode.


8.4

8.7 Machinery Space Ventilation Trials

a. Machinery space ventilation is to be tested in both configurations viz:

(1) When operating in `open ship' condition (Normal ventilation);

(2) When operating in `closed down' condition (Where recirculation cooling isfitted).

b. The systems are to be tested under full power conditions to determine thetemperature rise within the space(s) and to ensure that maximum acceptabletemperatures at high heat sources are not exceeded.

c. Trials are to be carried out in all vessels during Contractors Sea Trials and are toform part of the `First�of�Class' Subarctic and Tropical Trials.


March 2000

9.1

9. NBCD & FIRE FIGHTING ARRANGEMENTSRelated Documents: Statutory Instrument 1984 No 1218, ISO 5801, BS 848, STANAG4447, NES 118, NES 119 Parts 1 & 3, BR 2170 Vol 1, BR 6590(002), NATO AC 225(Phase VII/NSP WGE-1),CDE TN 574, CDE TN 595, SDN 002 630 353, SDN 002 630524, SDN 002 630 525, SDN 002 590 489; see also Annex A.

9.1 NBCD Subdivision (See NES 118)

a. To enable a ship to operate safely and effectively for an indefinite period in an`NBC Warfare' (NBCW) threat situation personnel and equipment are to beprotected and isolated from the external ambient conditions by the NBCDCitadel. The citadel, which encompasses the major portion of the enclosed partof the vessel, is to be continually pressurized above external atmosphere and itsboundaries are to be gastight.

b. In all but the smallest vessels (e.g. Minesweepers etc.) the total enclosed citadelmay be divided into `sub�citadels' by gastight bulkhead(s). In an NBCWsituation, access between adjacent sub�citadels and outside ambient air is to bevia Air Locks, and entry into the ship is normally only to be through CleansingStations.

9.2 Fire Fighting Subdivision (See NES 119 Part 1)

a. To ensure that, in a fire situation, smoke and flames can be contained withindefined boundaries the vessel is subdivided, throughout its total length, into anumber of fire/smoke zones.

b. Each fire/smoke zone is bounded by the ship's sides and gastight, vertical,transverse bulkheads that extend from the keel to the uppermost weatherdeck.The number of zones contained in a vessel is dependent upon its size and itsinternal construction.

c. The boundaries of NBCD sub�citadels and of fire/smoke zones are to becoincidental but a sub�citadel can contain more than one zone and zonalboundaries can extend beyond those of the citadel.

d. Air�conditioning and ventilation systems are to be autonomous withinfire/smoke zones. System design is to ensure compatible conditions in adjacentzones, especially in the critical areas of air balance and differential pressures.

9.3 Citadel Pressurization

a. An over�pressure, relative to the external atmosphere, is to be continuallygenerated within the citadel, the fresh air intake being the same in both theopen and `closed down' conditions.

b. There will be a variance in this over�pressure in the open and closed conditionsas the air loss will be greater in the `open ship' condition when Air Lockdisciplines should be but are not enforced and access doors between the citadeland outside ambient are only lightly clipped for air�conditioning reasons. In theopen condition, with unobstructed access between adjacent fire/smoke zonesand sub�citadels, an even over�pressure of at least 1.5 mbar is to be expectedthroughout the total citadel.


9.2

c. In the `closed down' condition, with zonal and sub�citadel boundaries securedand air�lock discipline enforced, the over�pressure generated in each zone,within citadel boundaries, is to be between 5 mbar minimum and 8 mbarmaximum with the differential pressure between adjacent zones being as closeto zero as possible. On no account is this differential pressure to exceed0.5 mbar. Machinery spaces (See Section 8) are to be pressurized to 3 mbarabove atmosphere.

9.4 Intake of Ambient Air

a. All entry of external ambient air into the NBCD citadel, in both the `closeddown' and òpen ship' conditions, is to be via AFU fans, each of which is to bededicated to that part of the citadel that is enclosed by the boundaries of aparticular fire/smoke zone.

b. In the `closed down' condition all incoming air is to be directed through the shipNBC Filters, that are an integral part of the AFU, before entering the citadel.

c. In the òpen ship' condition the incoming air is to pass through thePre�Particulate Filter but by�pass the Particulate Filter and the Vapour Filterwhich are to remain sealed. The fan selection is to take account of the differentsystem resistance occurring when the filters are ON or OFF line and a quick andeffective change over arrangement is to be provided.

d. The amount of ambient air drawn into each particular zone within the citadelby dedicated AFU fan(s) is to be sufficient to:

(1) Overcome the calculated uncontrolled leakage to generate the specifiedzone pressure. This is to be calculated based on the allowance given inClause 9.4.d.(5);

(2) Overcome the known controlled purging exhaust requirements in anòpen ship' condition;

(3) Overcome the known controlled purging exhaust requirements in a`closed ship' condition;

(4) Purge Cleansing Stations giving specified number of air changes perhour;

(5) Purge Air Locks giving specified number of air changes per hour;

(6) Replenish oxygen levels and thereby keep CO2 content below maximumpermitted levels (See Clause 9.4.d.(7) below);

(7) Overcome the air lost from the citadel other than purging requirements.

The amount of filtered fresh air required will therefore be the greater of the sumof 9.4.d(2)+ (4) + (7) in an òpen ship' condition or the sum of 9.4.d.(1) + (3) +(4) + (5) + (6) + (7) in a `closed ship' condition. Details of the above calculationsare also shown in Section 4.

9.4.1 Calculated Uncontrolled Leakages

a. Previous designs suggest that 900 m3/hr of filtered fresh air for every 3,400 m3

of citadel volume above the deep Water Line (WL) will satisfy Clauses 9.4.d.(1)and 9.4.d.(3).


March 2000

9.3

9.4.2 Known Controlled Leakages

a. These will be the known leakages through Cleansing Stations, Purged AirLocks, noxious spaces, and those which cannot be recirculated where filteredair is exhausted overboard.

9.4.3 Control Of CO2

By use of the formula,

Filtered air = BAV x n x a

(b2 � b1)

Where:

BAV = Breathing Air Volume;BAV Resting = 0.5 m3hr/person;BAV Light Work = 0.75 m3/hr/person;BAV Working = 1.25 m3/hr/person;n = number of persons;a = CO2 generated during breathing = 4%;b2 = permitted concentration of CO2 in fully

manned compartment;b1 = CO2 content of fresh air = 0.03%.

CO2 permitted concentration in various types of compartments:

Operational spaces 0.15%;

Berthing, resting spaces 0.25%;

Dining, lounge spaces 0.25%;

Workshops, offices, stores 0.45%.

a. The amount of fresh air required for general purposes in each fire/smoke zone,within the citadel boundary, is to be calculated in m3/hr as indicated in Section 4.

b. Additional AFU used only for special purposes, such as Air Lock purging andmachinery space pressurisation, are to be subjected to air flow only whencircumstances demand and in these cases filter by�pass arrangements are not tobe fitted(See Clause 9.5.c).

9.5 Air Filtration Units and NBC Filters

a. The current policy for vapour (gas) protection is by the use of activatedcharcoal. Other technologies are available but until these have been evaluatedand proven, charcoal is to remain as the filtering media for which this standardrefers.

b. The ship NBC filters are to be designed in accordance with STANAG 4447.They are to be installed in a Filter Station using the Design Guide for NBCFilter Station, NATO AC 225 (Phase VII/NSP WGE�1). SDN 002 630 353 givesguidance for a prototype 12 Filter Station which reflect the requirements of theabove standards for which variations of 3, 6 and 9 filter stations can be fitted.

c. The filters are the outward radial flow type with a high efficiency particulatefilter, co�located with a vapour filter.


9.4

d. To ensure the efficient removal of all NBC agents, it is essential that each filteras loaded in the AFU, whether fitted in parallel or series with other filters, issubjected to an air flow of between 270 m3/hr and 330 m3/hr.

e. The number of filters required in either a centralized or specialized AFU, is to bedetermined by dividing the total air quantity to be delivered through the AFU,calculated in m3/hr, by 300 m3/hr and rounding up.

f. For smaller vessels where it does not warrant the above built�in NBC FilterStations, the AFU will be to a new design which is still under investigation.These new generation AFU will be similar to those others described in thissection, however until they become available, the No 6 Mk 1 or the No 7 Mk 1,are to continue to be used until withdrawn from service (See BR 6590(002)).

g. Following the initial installation, a NDT challenge test is to be carried out onthe filters and their housings to determine whether there are any leak paths. Aprocedure for these tests is being written based on Chemical DefenceEstablishment Technical Notes (CDE TN) 574 and 595 dated 1983 and 1985.

h. AFU are to be of two types, viz:

(1) Centralised;

(2) Specialised.

9.5.1 Centralised AFU

a. These units are to provide all the continuous fresh air required bycompartments within the citadel, each unit being dedicated to a particularfire/smoke zone. They are to be an integral part of the ship's structure andconsist of:

(1) An Inlet Chamber, containing a weather inlet, which is protected from theoutside environment by a moisture/spray eliminator, blast valve,pre�particulate dust filter, and equipment to monitor and control therelative humidity of the air prior to it passing through the High Efficiencyand Vapour filters;

(2) A Filter Chamber, that in the `closed down' condition will house a numberof NBC Filters through which all air entering the unit will be drawn. Inthe `open ship' condition, this chamber may not be `loaded' with thestation on bypass and a resistance, equal to that of the filters, will need tobe introduced to ensure that system characteristics are the same in bothship states;

(3) A Fan Chamber, that will contain one or more fans sized and sited toensure that the specified air flow is drawn through each filter when theunit is fully loaded and `on�line'.

b. All incoming fresh or filtered air is to be trunked from the fans within thechamber to the relevant ATU or compartment.


March 2000

9.5

9.5.2 Specialised AFU

a. These units are operated only when required in an NBC warfare situation andcan be either an integral part of the ship's structure or free�standing.

b. When part of the structure they are to be similar in construction to theCentralised AFU except that all inlets and outlets are to be sealed when not inuse.

c. Free�standing units will be to a new design which is still under investigationand consist of a fan and outward radial flow filters similar to those describedpreviously for the main AFU, and will be encased in a free�standing, gastight,enclosure. Trunking from the unit to the air inlet is to be gastight and as shortas possible and where appropriate, protected by moisture/spray eliminators andsealed when not in use.

9.6 Purging

a. In the `closed down' condition certain Air Locks and all Cleansing Stations areto be continuously purged by bleeding air from the citadel through the Air Lockor Cleansing Station to the external atmosphere. The use of MOD approved,Automatic Bleed Valves (ABV) is the preferred method for achieving therequired air flow.

b. There are currently three approved automatic air bleed valves viz:

(1) SDN 002 630 524 which passes 595 m3/hr at 15 mm Differential Pressure(Dp) and 1020 m3/hr at 25 mm Dp;

(2) SDN 002 630 525 which passes 255 m3/hr at 15 mm Dp and 425 m3/hr at25 mm Dp;

(3) SDN 002 590 489 which passes 255 m3/hr at 15 mm Dp and 425 m3/hr at25 mm Dp.

c. Where it is not possible to achieve the specified number of air changes within anacceptable time, or other considerations make the use of bleed valvesimpracticable, purging by specialised AFU, is to be considered as an alternative(See Clause 9.4.3.b).

9.7 Air Locks (Citadel Exits)

a. In any Air Lock, specified as a citadel exit in the `closed down' condition, thepurging air flow is to be sufficient to provide between two and three air changesper minute, five air changes being required to remove all contamination.

b. Air inlets and outlets to the Air Lock are to be displaced as far as possible fromeach other to achieve maximum washing effect.

c. Where it is necessary to use a specialised AFU it is to be installed so that air canbe taken from the Air Lock, passed through NBC filters and discharged backinto the Air Lock. This arrangement is to be used when the design of the AirLocks and available citadel pressure is such that the required air purge ratescannot be achieved.


9.6

d. The air intake to the AFU is to be, fitted with a pre�filter, if not a part of the AFUand both intake and outlet are to be protected by a gastight cover so that thesystem can be sealed when not in use.

e. The specialised AFU fan if required is to be controlled locally from outside theAir Lock, within the citadel, and is to be inter�locked with the outer door so thatthe fan is operational only when the door is closed.

9.8 Cleansing Station (Contamination Control Area)

a. In an action/`closed down' situation, when the external atmosphere may becontaminated by NBC agents, entry into the citadel can only be via theCleansing Station.

b. The preferred method of purging these spaces is by the use of approved air bleedvalves (See Clause 9.5.b). These are to be fitted at the inner and outerboundaries of the Cleansing Station with intermediate bulkheads beingprovided with a simple pre�settable orifice opening.

c. It is to be possible to pass a continuous stream of personnel through theCleansing Station into the citadel satisfying the following:

(1) Processing time per man should not exceed 15 minutes;

(2) The interval between men is to be no more than 5 minutes;

(3) The largest volume compartment in the Cleansing Station prior to entryinto the citadel, must receive a minimum of five air changes in theprocessing interval between men.

d. Where it is not practicable to use bleed valves to achieve the required purging, aspecialised AFU is to draw air from the outboard (undressing) compartment ofthe Cleansing Station and discharge it via NBC filters into the final entry AirLock into the citadel. Air is to be returned to the AFU via pre�settable orificeopenings in the bulkheads that separate the compartments within theCleansing Station.

e. The air inlet to the AFU is to be fitted with a pre�filter if not a part of the AFUand both the inlet and outlet openings are to have gastight closures to enablethe system to be sealed when it is not in use.

f. AFU fan controls are to be positioned in the citadel, adjacent to the Air Lock andare to be easily identified.

9.9 Firefighting and Fire Precautions

a. NES 119 Parts 1 & 3 deals in general with the requirements for fire protectionand damage control for HM surface ships. The following paragraphs cover onlythose requirements that have an impact on the design of the ventilation andair�conditioning systems.


March 2000

9.7

9.10 Smoke Clearance/Containment - Policy (HM Surface Ships)

a. Smoke clearance should only to be undertaken near the seat of the fire when thefire is extinguished since all but small fires will have a virtually inexhaustiblesupply of smoke. Attempts to clear smoke before a fire is extinguished will riskthe introduction of more air into the fire. Therefore, smoke clearance isnormally a secondary action and should only take place when the fire has beenextinguished, unless smoke contamination/logging has reached suchproportions as to inhibit fighting the fire or managing the ship. Smoke controlis effected by the correct use of doors, hatches, smoke curtains and whereappropriate, fixed hatch waterwall nozzles. Main passageways which are usedas part of the ship's ventilation and air�conditioning system can lead to therapid spread of smoke, therefore their use is to be kept to a minimum. Supplyfans maybe used if appropriate to provide and maintain a small positivepressure in passageways and other smoke free areas of the ship.

b. In the event of a fire, ALL ventilation within a zone is to be `crash stopped',smoke boundaries established, and the fire extinguished by the fire�fightingteams. All air�conditioning fans are to be identified against one of the followingcategories:

A Smoke Clearance fans;

B Air Filtration Unit fans � centralised systems;

C Air Filtration Unit fans � specialised systems, e.g. machinery spaces, air�lock and cleansing station purging;

D Air Treatment Unit fans � central and compartment systems;

E Ventilation exhaust fans � hazardous and noxious spaces;

F Machinery Space Ventilation Supply and Exhaust fans;

G Mechanical Ventilation System fans outside the citadel and excluding machinery space fans.

c. The remote crash stopping of fans from a central position such as theMachinery Control Room (MCR), SCC or NBCD HQ, is to be based on the abovefan categories as grouped in individual smoke/fire zones and the followingfacilities are to be provided:

Cat A & B Individual fans are to be capable of being remotely stopped and restarted;

Cat C Local control only;

Cat D & E To be combined into one group per fire/smoke zone that isto be capable of being remotely crash stopped with local restarting;

Cat F Supply and exhaust fans to be combined into one group that is to be capable of being remotely crashed stopped with local restarting;

Cat G All fans, supply and exhaust, within each smoke/fire zone to be combined into one group that is to be capable of being remotely stopped with local restarting.


9.8

d. Smoke removal will not guarantee the removal of all toxic by�products, theability to be able to breathe without Breathing Apparatus (BA) is not a priority,however, visibility is, in order to provide damage assessment. To this endvisibility should be no less than 6 metres to 7.5 metres after 5 minutes to 6minutes of venting at a rate of no less than 20 changes of air per hour withineach zone deck. The density of smoke is dependent on the material(s) burnt andthe temperature achieved.

e. The accepted formula for the calculation for the mass of smoke produced by afire is:

M = 0.19 P Y 1.5

M = Mass of smoke produced in Kg/s;

P = Perimeter of fire in metres;

Y = Height of fire in metres.

This assumes a fire temperature of 800°C and an ambient air temperature of17°C (density 1.22kg/m3). The use of 17°C as the ambient temperature willgive approximately a 6% error over a temperature range of 0�35°C.

f. Smoke clearance is usually only to be carried out using negative pressureventing, i.e. the use of dedicated smoke clearance fans, portable fans and othersystem exhausts. Positive pressure venting can be used to accelerate smokeremoval after the fire has been extinguished, it may also be used to helpcontain/maintain smoke boundaries.

g. Smoke clearance is to be on a deck�by�deck basis within the zone, lower decksfirst, to be controlled by valves, deck�by�deck. Zones can be breached to allowthe entry of fresh air, but extraction is to avoid smoke laden air migrating toother unaffected decks and compartments.

h. Main Machinery and other dedicated system exhausts may also be used toremove smoke from within the zone(s) they are situated in. It should be notedthat their use can contaminate non�affected areas within other zone(s) or theship.

i. Dedicated smoke clearance fans are to be Hot Gas fans in accordance with BS 848, (See also ISO 5801). They are to be reversible, capable of withstandingtemperatures of 600°C for 1 hour and specific shock and vibration levelsappropriate to the particular vessel without damage or a subsequent drop inperformance.

j. Dedicated smoke clearance fans are to have a minimum capacity of 4,000 m3/hrat 150 mm water gauge and are to be individually and remotely operable fromthe ship control centre.

k. Dedicated smoke clearance fans are to be capable of being selected so that in the`open ship' condition, in any single zone, with both clearance systems operatingin the most effective configuration and with no restriction on the entry of freshair into the zone, the maximum time to complete a total air change will be3 minutes.


March 2000

9.9

l. All dedicated smoke clearance exhaust trunking to be watertight, of galvanisedsteel construction and suitably insulated, with ships side and `Red risk'butterfly valves automatically interlocked to their respective fans with amanual over�ride. Hose connections fitted into the trunks of smoke clearancesystems, are to be provided at each deck to enable stubborn pockets of smoke tobe dispersed using portable equipment. System discharges must be sited wellclear of NBC filter intakes.

m. When the ship is in Condition ALPHA, smoke removal is to be provided by andis limited to the amount of over�pressurisation of Citadel can accommodate.Additional fans are not to be provided for this operation, but a means of`venting' excess citadel pressure must be provided. If a negative pressure isachieved due to the use of Smoke Clearance Fans, the command will need toassess and prioritise the ships requirements.

n. In order to better assess damage and to accelerate re�occupation, priority forsmoke clearance is to be given to passageways, lobbies and essential spaces,however this is largely dependent on prevailing conditions and commandpriorities.

o. In operational and electrical spaces of `high operational' value (See NES 119Part 1), a slight positive pressure is to be provided to restrict the ingress ofsmoke, both in `closed' and `open' conditions. When the ventilation is stopped,an automatic means of preventing the ingress of smoke is to be provided.

p. Apart from the limited arrangements when in Condition ALPHA, smokeremoval and containment arrangements are common for both peace time andor scenarios.

q. Portable water driven fans (RAMFANs) with flexible ducting are to be providedat each Fire and Repair post to augment smoke removal (But noting thelimitations at Clause 9.10.k).

r. RAMFAN flexible ducting connections are to be fitted in the main trunks ofsmoke clearance systems on each deck to enable stubborn pockets of smoke tobe dispersed.

s. Smoke removal arrangements are to be demonstrated prior to `ShipAcceptance'. Smoke generators are to be used and test forms raised whichindicate the number of air changes per hour per compartment have beenachieved. The smoke removal arrangements to be demonstrated by zones.

9.11 Crash Stopping of Fans

a. All air�conditioning and ventilation fans are to be identified against one of thefollowing categories:

(1) Smoke Clearance fans;

(2) Air Filtration Unit fans, centralized systems;

(3) Air Filtration Unit fans, specialized systems and Cleansing Stationpurging;

(4) Air Treatment Unit fans, central and compartment systems;


9.10

(5) Ventilation exhaust fans within the citadel serving hazardous andnoxious spaces;

(6) Machinery Space Ventilation fans both supply and exhaust;

(7) Mechanical Ventilation System fans outside of the citadel (ex machineryspace fans).

b. The stopping and starting of fans is to be based on the above categories. Whereremote operating is required, this is to be from the SCC or MCR or NBCD HQ asfollows:

Cat A & B Individual categories are to be grouped and be capable ofbeing remotely stopped and restarted on a Zonal basis;

Cat C Local control only;

Cat D & E Fans are to be combined into one group per Fire/Smoke

Zone that is to be capable of being remotely stopped with

local restarting;

Cat F Supply and exhaust fans are to be combined into one

group that is to be capable of being remotely stoppedwith local restarting;with local restarting;

Cat G All fans, supply and exhaust, within each Fire/Smoke

Zone are to be combined into one group that is to be

capable of being remotely crash stopped with local

irestarting.

9.12 High Risk Areas

9.12.1 Galleys (Also See Section 5)

a. To reduce fire hazards all ventilation and air�conditioning trunking withingalleys and the galley system throughout its entire length is to be made of MildSteel (MS), Galvanized After Manufacture (GAM), except where it forms part ofa canopy when it is to be of stainless steel.

b. Exhaust terminals in canopies over equipments such as ranges, fryers, grills,etc., are to be fitted with grease filters that can be easily removed and cleaned.

c. Exhaust branches, fitted with grease filters, are to be protected by fire flapswithin the galley that are:

(1) Where possible sited between 2 m and 3 m outside of the canopy andpositioned en route between equipment served and the galley exit;

(2) Arranged to close in the direction of the air flow;


March 2000

9.11

(3) Controlled by a flat bar operating lever (either directly or remotely gearedas dictated by the galley layout) with the open and closed positions clearlymarked. The lever is to be painted red with the instruction `SHUT INEVENT OF FIRE' mounted adjacent to it. It is to be clearly visible andcapable of being easily operated by any man standing on the deck. Wherecontrol by a solid lever is not practicable, a dual cable, pulley and conduitarrangement is to be fitted, the cables being of a robust, non�stranding,non�type and the conduit of mild steel tube. In this arrangement theoperating lever is to be marked as above but is to be located outside thegalley close to the power switches;

(4) Capable of being retained in the `OPEN' or `SHUT' position undernormal ship movement and vibration conditions by means of a suitablequick release/retaining arrangement, e.g. spring loaded ball catch orspring clip. Any fitting that requires a nut or bolt to be released before thecontrol lever can be operated is not acceptable.

(5) Fire flaps with a CO2 injection point are to be fitted either side ofodour/carbon filters, sited in the galley trunking (See Figure 9.1).

d. A local crash stop facility is to be provided for the galley air�conditioning fan/s.This is to be sited outside of the galley and close to other emergency powerswitches adjacent to the galley exit. The fan starter is to be painted red for easyidentification with the instruction `SWITCH OFF IN THE EVENT OF FIRE',mounted close to it.

9.13 Highly Flammable Stores and Explosive Gases

a. Systems serving compartments that contain the above materials, are to includeflameproof gauzes, butterfly valves as appropriate and fans are to be eitherspark resistant or spark resistant with flame and explosion proof motors (SeeSection 5 and Figure 9.2).

9.14 Fire Flaps

a. In addition to those fitted in galley systems, fire flaps are also to be fitted:

(1) In ventilation and air�trunks that pass through main bulkheads that aredesignated as fire barriers.

(2) At compartment bulkheads in trunks passing into essential spaces. Thesefire flaps can perform the dual roles of sealing the compartment when anover pressure needs to be generated, and preventing the spread of fire andsmoke from within the compartment. For additional informationreference should also be made to NES 119 Part 1.

b. Although fire flaps can be fitted with automatic operating facilities (softsoldered links), they should, in all cases, be positioned as close to thecompartment that they are protecting to avoid unnecessary spreading ofsmoke. Where these are fitted at deckhead level, they are to be easily reachedand may entail ladder rungs, steps, access and/or means of remote operation.Signs at eye level are required to identify the fire flaps and compartmentsserved.


9.12

L = WIDTH OF TRUNK (W) PLUS 160 mm

CEILING LINING

DIM

EN

SIO

N T

O S

UIT

DE

PT

H O

F T

RU

NK

ING

DIM

EN

SIO

N T

O S

UIT

WID

TH

OF

TR

UN

KIN

GCASING: Mild Steel (M.S). (G.A.M.)

AS ADJACENT TRUNKING, MINIMUM 1.6 mm (16 SWG)

DIRECTION OFAIR FLOW

ADJUSTABLE HEAVYDUTY BALL CATCH

THROUGH LINING. ACCESS PANEL TO BE FITTEDSPINDLE WITH OPERATING LEVER TO EXTEND

IN LINING FOR MAINTENANCE PURPOSES.

SIDE

ELEVATION

FLAP IN OPEN POSITION

SUIT ADJACENTTRUNKING

FLANGES TO

WID

TH

= ’W

’

BALL CATCH OR SPRING CLIP

COVER PLATE

FLAP IN CLOSEDPOSITION

VIEW OF UNDERSIDE

RIVETED TO 3 SIDES OF BOX AND FACED WITH15x15x3 mm FLANGED PLATE ANGLE STRIP

WOVEN GLASS FIBRE COATED ON BOTH SIDESWITH SILICONE RUBBER COMPOUND.

OPEN

SHUT

FIRE

WIRE (IN CONDUIT)

FLAPBOX

CONTROL ARRANGEMENT WHEN WIRE IS USED

IN LIEU OF DIRECT OR ROD CONTROL

OPERATING LEVER

COMPOUND, CEMENTED TO STOOLBOTH SIDES WITH SILICONE RUBBERWOVEN GLASS FIBRE COATED ON

COMPRESSEDGLASS FIBRE

TO 2 mm.

STOOL WELDED3 mm THICK M.S.

TO VALVE CASING

SHOWING DETAILS OF SEAL AROUND SPINDLE

ENLARGED VIEW WITH COVER PLATE REMOVED

FIRE FLAPOPERATING LEVER

Figure 9.1 – Typical Fire Flap


March 2000

9.13

TRUNK AREA A

TRUNK AREA 2 x A

TRUNK AREA A

GAUZE FRAME

20�

20�

NOTICE (WHITE LETTERS ON A RED BACKGROUND)TO BE DISPLAYED HERE AS FOLLOWS:‘THIS BECOMES A DANGEROUS AREA WHENGAUZE FRAMES ARE REMOVED FOR SERVICING’

ALL PORTABLE AND MOVABLEFITTINGS TO BE MADE OF BRASSOR NON-FERROUS METAL

20 x 30 mm FLAT BAR FRAMECLAMPED BETWEEN ANGLE ANDCOPPER GAUZE AREA 2 x A

30 x 6 mm SEATING WELDEDTO TRUNK (CONTINUOUS) TOPSURFACE TO BE FAIR.

WHITE LETTERS ON A RED BACKGROUND‘GAUZE FRAME’ TO BE PAINTED HERE IN

FILLING PIECE WELDEDTO TRUNKING

WEDGE PIECE WELDEDTO TRUNK TO TRUNK

M.S. BOLT WELDED

BY M5 N.B. SCREWS SPACEDAPPROXIMATELY 75 mm APART.

AIRTIGHT LEATHER SEATING SECURED TOGAUZE FRAME WITH SUITABLE ADHESIVE

25 x 25 x 3 mm CONTINUOUS BRASSANGLE BAR FRAME (TO FORM WEDGES)

M10 WING NUT

180 mm

75 mm

180 mm

Figure 9.2 – Typical Flameproof Gauze


9.14

9.15 NBCD Ventilation Board

a. The NBCD Ventilation Board is required to be produced in accordance withNES 119 Part 3, i.e. colour codes are to be used to identify systems, ventilationATU systems are to be clearly marked including arrows to indicate air flow.Additionally in the case of RFA vessels, all fire dampers are to be shown withclear indication of the compartments served. The Ventilation Board can beelectronic.

b. Ventilation location, Risk and Control markings are to be provided inaccordance with BR 2170 Vol 1.��

9.16 Fire Precautions in Royal Fleet Auxiliary Vessels

a. The above standards are applicable to all RN Surface Ships, but additionally,those vessels that are to be included in the register of Merchant Shipping, i.e.RFA, are also to comply with the Merchant Shipping (Fire Protection)Regulations � Statutory Instruments 1984 No 1218. Where a NES andMerchant Shipping Regulations differ, the more stringent of the twoinstructions is to be applied, with the proviso that the application of theMerchant Shipping Regulations, must never, in any circumstances, jeopardizethe integrity and function of the NBC citadel (See Clause 1.2 d).


March 2000

10.1

10. FANSRelated Documents: ISO 5801, BS 848, NES 119 Part 1, NES 627, NES 628, NES 629, NES 810 Part 2, NES 1004, BR 1754 ; see also Annex A.

10.1 Fan Selection

a. General purpose fans are to be selected from three basic types, viz:

(1) Centrifugal (backward curved/inclined impeller);

(2) Axial Flow;

(3) Mixed Flow.

The type selected for any particular duty being governed by the air flow andtotal pressure required by the system, the noise generated and the spaceavailable.

b. The range of general purpose fans selected for a class of vessel is to be restrictedas far as practicable to facilitate interchangeability and limit stores holdings.

c. Fans for ventilation and air�conditioning systems, unless otherwise agreed, areto be selected with a 10% margin over the design air volume when reckoned onthe constant orifice line. (See Figure 10.1).

d. When the specified duty, noise level and space considerations can be satisfied bymore than one fan, the fan that generates the least noise is to be selected,without prejudice to cost.

e. For each range of fans, and if necessary each individual fan or fan package, thatit is intended to include in the design, a STR is to be prepared by the shipbuilderor his representative. The STR must reflect and be compatible with the NavalStaff Requirement (NSR) for the vessel.

10.2 Materials

a. All materials used in the construction of the fans are to conform with theappropriate NES and MOD specifications or, where such do not exist, with theappropriate ISO or British Standards (BS).

10.3 Construction

a. The construction is to be as light as possible consistent with sufficient strengthto resist damage and distortion when subjected to the specified vibration andshock levels.

b. The construction and finish of the fans and fan casings, etc., is to be such thatthe planned life will be achieved when the fans are continuously subjected to themost severe environmental conditions, handling air laden with salt and/orother airborne contaminants as dictated by its position within the ship (See NES 1004).

c. When assembled every fan casing is to be airtight and capable of satisfying thetest requirement specified in BS 848/ISO 5801.


10.2

Procedure

1. Draw a vertical line at the design air volume to intersect the fan curve.

2. Spot point on fan curve at design volume + margin (10% for compartment ventilation and air conditioning systems).

3. Through this point draw a constant orifice line of slope 2 in 1 (accordingto the law 4 times pressure against 2 times volume) to intersect the vertical line at the design air volume.

4. Calculate system trunk sizes on flow and pressure conditions appertainingto this point of intersection.

4. CONDITION TO BE USED FOR TRUNK SIZING

1. DESIGN AIR VOLUME

2. AIR VOLUME PLUS MARGIN(DRAWN FOR 10% MARGIN)

FAN CHARACTERISTIC CURVE

Figure 10.1 – Application of Constant Orifice Line to Design Margins


March 2000

10.3

10.4 Motors

a. The manufacture, documentation and testing of fan motors is to conform withNES 627, 628 and 629, unless otherwise specified, such as `best commercialmarine standard'.

10.5 Availability, Reliability and Maintainability (ARM)

a. The minimum ARM requirement for all fans is:

Planned life 25 yearsMean Time Between Failures 10,000 hoursMean Time Between Failures Not Repairable at Sea 100,000 hoursMean Time To Repair at Sea 4 hours

10.6 Noise

a. Maximum acceptable Sound Power spectra are to be specified in the STR foreach fan or range of fans. These Sound Power Levels are to be compatible withthe maximum total noise levels (Sound Pressure Levels � SPL) permitted inrelated ship compartments, as specified in NES 810 Part 2. Where appropriatethe specified sound power levels are to take account of the calculated noiseattenuations and gains afforded by the installed ventilation/air�conditioningsystems and the absorption and reflection levels within the compartmentsserved.

10.7 Shock

a. If required, a shock plan and statement of shock levels to be met will beproduced at the outset of the design. Fans are to be designed to withstandwithout damage or degradation in performance the specified shock levels,either by manufactured strength design or by further support from appropriateshock mounts (See Clause 10.11.a).

10.8 Vibration (Self Generated)

a. Self generated vibration levels are, if required to be within the limits identifiedby the ship platform at the outset of the Heating Ventilation andAir�Conditioning (HVAC) design.

10.9 Vibration (Externally Generated)

a. The fan and motor assembly is to be, if required, capable of withstandingwithout degradation in performance the vibration levels appropriate to itsinstalled position identified in the ship platform at the outset of the HVACdesign.

10.10 Fan Testing

a. Fan performance is to be measured in accordance with BS 848 Part 1/ISO 5801,Installation Type D and data correction tables to suit other installations are tobe provided. A set of characteristic curves showing total pressure, staticpressure, total efficiency, static efficiency and shaft power plotted against inletvolume air flow and covering the normal working range of the fan, is to beprepared for standard air. These curves are to be plotted on 2 x 2 cyclelogarithmic sheets having a graticule of approximately 25 cm square.


10.4

b. Noise tests are to be conducted and reported in accordance with BS 848/ISO 5801. In addition a curve of Sound Power Level (in dBW) over the operatingrange of fan volumes is to be included with the fan characteristics.

c. Shock testing, if required, is to be in accordance with the demands as identifiedby the ship platform at the outset of design.

d. Self generating vibration tests, if required, are to be conducted and reported inaccordance with the requirements outlined in the ship platform at the outset ofdesign.

e. Externally generated vibration tests are to be conducted in accordance withNES 1004.

f. When fans are an integral part of a packaged unit fitted in ship, performance,noise, shock and vibration testing is to be carried out on the total assembly.

g. Where appropriate, acceptance tolerances are to be specified in the agreed STR,but in general fans are to be rejected if they do not meet BS 848 Class `B'tolerance band (See also ISO 5801).

h. Prior to final acceptance a `Configuration Definition Package' is to be preparedfor each range of fans and, where necessary, each individual fan and fan packagethat it is intended to include in the complete air�conditioning and ventilationsystem design. The package is to include detailed drawings, parts lists, testreports, test results and certification, characteristic curves, etc., and are to besubmitted to the MOD for records and future support.

10.11 Mounting and Siting of Fans

a. The position of a fan within the vessel and the vessels specified shock resistingcapabilities will determine the anticipated shock level it may need to sustain.When this level exceeds that to which the fan was manufactured the fan must besupported on the appropriate shock mounts but where shock mounts are notrequired the fans are to be held on resilient pads to attenuate vibrationtransmissions (See Clause 10.7.a).

b. Flexible connections are to be fitted between fans and associated trunking onboth the inlet and outlet sides to reduce noise transmissions and facilitate fanremoval. These connections are to be of hard�wearing, fire resistant materialwhich, although flexible, will not allow air leakage. The method of fitting theseconnections to fan and trunking spigots is to be such that it will permit shockdeflections, prohibit air leakages and prevent slippage due to vibration.

c. Where practicable fans are not to be sited in, or supported on the boundaries to,operational and accommodation spaces.

d. Fans are not to be sited in, and preferably not adjacent to magazines,ammunition spaces and other dangerous areas.

e. Axial and mixed flow fans are not to be used for venting dangerous gases unlessthey are sited in ducting outside the area of possible contamination, haveindirect drive or are of the `Shielded Motor (Bifurcated)' type, and are fittedwith spark resistant features.


March 2000

10.5

f. Axial and mixed flow fans are not to be fitted horizontally at the lowest point ina section of trunking where water is liable to accumulate.

g. When a standby fan is required, it is to be fitted parallel to the primary fan, thenecessary air�tight flaps being introduced to prevent recirculation occurring.

h. Even in extremely congested areas, such as ATU, space must be allowed toenable individual fans to be maintained in situ and when necessary removed forrepair and servicing. In every case it must be possible to demonstrate that thetime required to exchange a fan or motor is not greater than 4 hours.

10.12 Special Fans

a. Fans that need to be located in an area where atmospheric contamination couldoccur due to the build up of an explosive mixture must be of the `SparkResistant Type A or B' as classified in BS 848/ISO 5801.

b. In exceptional cases when fans serving compartments and storeroomscontaining hazardous stores classified as CLASS 1 or CLASS 2 in accordancewith BR 1754, are sited within the space served they are to be of the centrifugaltype fitted with a flameproof motor in addition to spark resistant features.

c. In particular ship classes, only fans designated as `minimum magnetic' are to befitted. The acceptable range of magnetic signatures for these fans will bedefined in the appropriate Naval Staff Target (NST) and every individual fanand fan package is to be tested and certified as magnetically satisfactory prior toacceptance.

d. Wherever possible, the total air flow volume supplied by mechanical ventilationsystems is to be capable of being reduced in cold weather to limit the heat loads.This is to be achieved by selecting two speed or variable volume fans. However,care is to be taken that sufficient air flow is maintained across electric in�lineheaters to avoid tripping. This arrangement is to apply to those spacesgoverned by temperature rise and not where governed by air changes.

e. Dedicated fans for Smoke Clearance systems are to be hot gas fans inaccordance with BS 848/ISO 5801, i.e. they are to be capable of operating intemperatures of up to 250°C for a period of at least 60 minutes without theperformance levels stated in the appropriate STR being degraded.

f. RAMFAN portable water turbine fans, with flexible trunking, are to beprovided to ventilate spaces that are not fitted with permanent ventilation orair�conditioning arrangements and to supplement damage control equipmentin clearing smoke from difficult areas.

10.13 Fan Markings

a. Every fan is to carry `Location and Control' markings as specified in NES 119Part 1. In addition each fan is to bear a plate showing:

(1) The type and size of fan;

(2) The MOD serial number of the fan;

(3) The duty, e.g. air�conditioning, citadel exhaust, ventilation exhaust,ventilation supply, air filtration, smoke clearance, etc.;

(4) A list of all compartments served by the fan with their position within thevessel, i.e. deck and frame numbers.

b. Plates engraved with an arrow are to be secured to each fan casing to indicatethe direction of air flow and of rotation of the impeller.


10.6


March 2000

11.1

11. TRUNKING AND FITTINGRelated Documents: The Merchant Shipping (Fire Protection) Regulations StatutoryInstrument 1984 No 1218, NES 119 Part 1, NES 155 Part 1, NES 360, NES 703, NES705, NES 763, ; see also Annex A.

11.1 General

a. The following material standards are the minimum requirements applicable toall ducting installed in RN Surface Warships.

b. RFA Vessels, that are included in the register or Merchant Shipping, are tocomply with these standards and with those specified in The MerchantShipping (Fire Protection) Regulations Statutory Instrument 1984 No 1218.Where there are differences between these two sets of regulations the morestringent standard is to be applied (See Clause 1.2 d).

11.2 Non-Watertight, Non-Gastight Trunks

a. Trunking in this category may be manufactured from a variety of materials,e.g.:

(1) Textiles;

(2) Aluminium alloy;

(3) Galvanized mild steel;

(4) Composite materials (e.g. filament wound glass/phenolic resin).

b. The material selection will entail the consideration of some or all of thefollowing:

(1) Cost effectiveness;

(2) Weight;

(3) Resistance to internal pressure and vacuum;

(4) Thermal conductivity;

(5) Corrosion resistance;

(6) Acoustic characteristics;

(7) Behaviour under external shock and vibration;

(8) Thermal expansion coefficients;

(9) Resistance to air flow;

(10) Satisfying the conditions of NES 705;

(11) Ease of installation and maintenance;

(12) Whether it is an Essential or Non Essential system;

(13) Ease of cleaning.


11.2

c. Commercial trunking kits using pre�formed, standard, trunking sections andcomponents may be used for these systems. Where it is intended to employ kitsusing materials other than textile aluminium or galvanized mild steel priorapproval is to be obtained from the MOD and test results that compare theperformance of the proposed material with that of aluminium, in all of the areaslisted above, are to be submitted when this approval is sought.

d. Where systems are tailor made for the ship and manufactured by theshipbuilder, or his representative, this category of trunking may be textile or ofaluminium alloy and rectangular in shape.

(1) The minimum thickness of the non�textile material, normally aluminiumalloy, is to vary with the length of the longest side, as follows:

Longest side of a rectangular trunk Material Thickness

Up to 250 mm 1.2 mm

251 mm to 600 mm 1.6 mm

Over 600 mm 2.0 mm

(2) Where the longest sides are 500 mm to 750 mm in length the trunking is tobe stiffened by a 1.6 mm thick, swaged plate, riveted longitudinally alongthe centre of the sides, or by the use of swaged trunking.

(3) Trunking with the longest side in excess of 750 mm is to be dividedlongitudinally by a plate, of similar thickness and material to that of thetrunk, riveted or welded, as appropriate, throughout its length. Wherethe aspect ratio of the trunk is greater than two, lightening holes may becut in the longitudinal dividing plate to reduce weight.

(4) Transverse joints are to be riveted slip, bolted flange, or where thethickness of the material allows, a continuous butt weld. In any run oftrunking, sufficient portable sections, i.e. those secured at both ends bybolted flanges, are to be incorporated to enable the total length oftrunking to be cleaned when they are removed.

(5) All joints, except for those welded, are to be made airtight by the use of asuitable flexible mastic sealer.

11.3 Textile Ventilation Trunking

a. Textile ducting (also referred to as `socks') may be permeable, i.e. air ispermeated through the weave of the cloth. The level of delivery is dependant onthe static pressure within the sock combined with the tightness of weave.

b. Alternative textile ducting may be fitted with either slots or nozzles todistribute the air. It is possible to combine all configurations within a system toprovide the required distribution.

c. The low material resistance combined with linear percolation minimises theloss of pressure.


March 2000

11.3

11.3.1 Advantages

a. Efficient Air Distribution � Air is defused through the whole length of the socksproviding an efficient mix of air within the compartment.

b. Draught Free � The low impulse system is based on the principle of natural airmovement, dependant on temperature differentials, the cold air displaces thewarmer air. Textile has the ability to handle large volumes of air which providefor a high number of change when desired.

c. Recirculation Ducting � Is not required within the compartment since superiordistribution of the supply air over the whole of the compartment eliminates theneed for a network of recirculation ducting. A central return air point is all thatis required.

d. Energy Saving � The efficient air diffusion with the minimum of heatstratification allows for a reduced system operating period, however, the fan canbe expected to continue running even when compartment temperatures aresatisfied to avoid heat stratification and ensure adequate ventilation.

e. Aesthetic Appearance � Is achieved through uniform sizing of the socks,combined with a choice of colours and tailored circular, semi�circular orquadrant in section, the fitting of such systems can enhance compartmentdecor.

f. Low Weight � Assists in ease of fitting and handling for cleaning. It can be fittedto light supporting structure, and may contribute to improved ship stability.Conventional thermal insulation is not required, the high induction ratecombined with the linear delivery means a short contact time prevents the dewpoint being reached. Condensation forming on the external surface even with acold air supply is therefore avoided.

g. Reduced Air Noise � No resonance is experienced, the ducting material absorbsnoise.

h. Flexible Mounting � Allows systems to be readily reconfigured if so desired. Itcan be easily removed in way of shipping routes or during maintenance periodsto provide improved access.

i. Cleaning � Is achieved by removing the socks which are connected together intoconvenient lengths by the means of zips and replacing with a replacement set.The dirty socks can be washed using a standard washing machine. Continuousair movement with no obstructions over a permeable sock will prevent dustfrom settling. Cleaning on a regular basis will be necessary since the weaveprovides a second line filtration system for the supply air. It therefore followsthat quality of air provided by textile ventilation is significantly cleaner than forconventional systems.

j. Repair and Modifications � For textile trunking can be easily achieved, the clothcan be patched/stitched. Where modifications are required, additional legs canbe added to meet with compartment changes.

k. Economic Storage & Transportation � Can be achieved since when packed, thesocks take up relatively small volume of space. 100 metres of 800 mm clothequates to a cubic metre.


11.4

l. Fire Retardency and Toxicity � Characteristics are considered safer thanconventional aluminium systems.

11.3.2 Disadvantages

a. Few disadvantages are thought to exist, however, patternisation of componentparts has not been addressed.

b. The evolution of maintenance and cleaning of the trunking requires bettermanagement control than presently exists for conventional systems.

11.4 Gastight and Structural Trunks and Trunks Subjected to Rough Usage or High FireRisk Including Smoke Removal Systems

a. Trunks that, in the `closed down' condition could convey contaminated airthrough the citadel, or serve compartments within the citadel but are routedoutside of its boundaries, or pass through compartments that are`contaminated if used', are required to be gastight.

b. Structural trunks are those built as an integral part of the ship's structure withdecks and/or bulkheads being utilized as trunk sides. The thickness of theplating used to construct the other sides is to be as specified below unlessstrength or watertight integrity considerations dictate otherwise.

c. Trunks subjected to rough usage are typically those sited vertically inpassage�ways and horizontally in way of hatches through which stores,machinery and other heavy/bulky items need to be transported. This categoryalso includes those sections of trunking that have to be removed to clearshipping/unshipping routes.

d. Trunks subjected to high fire risks are typically all trunks passing through andcontained within galleys, magazines, flammable stores, machinery spaces, etc.

e. These trunks are normally where thickness allows without distortion, to bemanufactured of Mild Steel�Galvanized After Manufacture (MS�GAM), withthe following exceptions:

(1) Where trunk thickness could possibly lead to distortion from galvanisingafter manufacture, the material may be mild steel galvanised plate withzinc spraying of destroyed galvanising at welded joints;

(2) Where trial results show that specialist, pre�formed, commercial kits,that use other materials such as composites, can out perform galvanizedmild steel in all the relevant areas without incurring significant expense.In these cases MOD approval is to be obtained before such commercialkits are utilized;

(3) Gastight trunking contained within the citadel may be manufactured, bythe shipbuilder or his representative, using aluminium alloy of the samethickness as the alternative mild steel;

(4) Structural trunks are to be of ungalvanized, mild steel plate,continuously butt welded to the ship's structure with the interiorsurfaces painted in accordance with NES 763;

(5) For difficult shaped sections of trunking abrasive blasting and zincspraying of both external and internal surfaces is an acceptablealternative to GAM.


March 2000

11.5

f. Where trunks are tailor�made for the ship and are manufactured by theshipbuilder or his representative the following guidelines are to be adhered to:

(1) Trunks are generally to be rectangular in shape and the thickness of thegalvanized mild steel is to vary with the length of the longest side asfollows:


Up to 250 mm 1.6 mm

251 to 600 mm 2.0 mm

Over 600 mm 3.0 mm

(2) Where the longest sides are 500 mm to 750 mm in length the trunking is tobe stiffened by 25 x 25 x 3 mm angle, intermittent welded, longitudinally,along the centre of the sides;

(3) Trunking with the longest side in excess of 750 mm is to be subdividedlongitudinally by a welded plate of the same material and thickness asthat of the trunk. Where the aspect ratio of the trunk is greater, then twolightening holes may be cut in the longitudinal dividing plate to reduceweight;

(4) Longitudinal joints are to be continuous butt weld;

(5) Transverse joints are to be a continuous butt weld or, except for structuraltrunks, flanged. Flanges are to be welded to the trunk and joints are to bemade gastight by using a suitable flexible mastic sealer with a siliconcovered fibre woven cloth.

11.5 Watertight Trunks

a. Watertight trunks are to be installed, in accordance with NES 119 Part 1, toensure the integrity of the vessel's watertight subdivision and to containflooding within the Red Risk Zone or `V' lines as indicated in the relevantSubdivision Policy Paper.

b. These trunks are normally to be rectangular in shape, manufactured ofMS�GAM, the thickness of the material varying with the longest side of trunkas follows:


Up to 250 mm 1.6 mm

251 to 400 mm 2.0 mm

Over 400 mm 3.0 mm

c. Stiffening, longitudinal subdivision, transverse and longitudinal joints are tobe as specified for gastight trunks that are manufactured by the shipbuilder orhis representative.

11.5.1 Trunk Installation.

a. When installed the interior surfaces of the trunks are to be smooth, free ofobstructions and, with the exception of structural trunk, left unpainted.


11.6

b. All trunks are to be well supported, hangers being spaced 2.0 m to 2.5 m apartand at the ends of trunks that are connected to removable sections. Hangers areto completely encircle the trunking and where insulation is fitted they are toonly be in contact with the external surface, care being taken to ensure thatthey do not provide a `thermal bridge' between trunk and atmosphere (SeeFigure 11.1).

c. Where dissimilar metals have to be connected together, the preparation of thefaying surfaces is to ensure that the risk of corrosion is minimal. The preferredmethod is for the surfaces to be degreased, etched and coated with a provencorrosion inhibitor.

d. In each system drain plugs are to be provided at low points in the trunkingwhere water may collect and self draining terminals are to be fitted at weatheropenings.

e. Watertight butterfly valves, selected from NES 360, are to be fitted as requiredto maintain the integrity of watertight and gastight structure. These valves arenormally to be fitted directly to the bulkhead or deck but in exceptionalcircumstances a distance piece or coaming, manufactured from material of thesame type and thickness as that of the bulkhead or deck, may be used.

f. Where trunking must pass through a strength deck or major bulkhead theopening is to be sited, shaped and strengthened in accordance with NES 155Part 1. To reduce the size of the opening, and consequently the size and weightof the butterfly valve, if fitted, the trunking either side of the bulkhead or valvemay be in the form of a circular `Venturi' section.

g. All trunks that pass through major bulkheads and decks but are not fitted witha isolating valve at the point of penetration are to be provided with portablesections to enable the ventilation to be blanked in order to periodically air testthe integrity of the compartments where required.

h. Textile trunking should only be installed in areas of high fire risk/rough usageafter consultation with the DA and the sponsor of this NES.

11.6 Vulnerability

a. To give ready access to ship's side plating and to minimize possible damage,trunks, pipes and fittings, associated with ventilation and air�conditioningsystems, are to be sited well away from the ship's side in the Red WatertightRisk Zone especially on or near the waterline. They are also to be sited clear ofthe after sides of collision bulkheads from below to well above the deepwaterline.

b. Textile trunking may be fitted in compartments below the waterline but dueconsideration must be given to the effect of damaged trunking on emergencypumps.


March 2000

11.7

WELDED TO DECKHEAD

M6 NUT & LOCKING NUT

INSULATION

HANGAR SUPPORT FOR TRUNKING 150 mm TO 300 mm WIDTH

VENT TRUNK

M6 ROOFING BOLT

25 mm x 3mm M.S. STRAP

95x2 mm M.S.SADDLE

(GALVANISED)

UP TO 150 mm

50x2 mm M.S.SADDLE FOR

WIDTH

25 mm x 3 mm M.S. STRAPWELDED TO DECKHEAD

M6 NUT & LOCKING NUT

M6 ROOFING BOLT

STIFFENING ARRANGEMENT TO SADDLE FOR TRUNKING OVER 300 mm WIDTH

95x2 mm M.S.

(GALVANISED)SADDLE

SNAPED END PLATES

2 mm M.S. SWAGED STIFFENERSEALED EACH END, IF REQUIRED

POP RIVETS

VENTILATION TRUNKING &NOTE :

INSULATION NOT SHOWN

Figure 11.1 – Typical Hanger Supports


11.8

11.7 Trunking - Associated Fittings

a. As a general policy the fittings associated with the air�conditioning andventilation systems are to be selected from the appropriate lists of current NSN.Where it can be demonstrated that use of alternative fittings would be moreeffective or would give significant financial savings without loss of quality,MOD approval is to be sought for installation of such items .

11.8 Weather Terminals

a. The design and selection of materials for terminals and associated fittings,subjected to external atmospheric conditions, is to ensure that potentialsources of corrosion at points of contact such as hinges, clips and fastenings, areeliminated.

b. All openings in weather boundaries are to be fitted with grilles of GlassReinforced Plastic (GRP) or other composite material, to avoid the systemsbeing fouled by debris or vermin. These grilles are to be left unpainted and areto be readily accessible and capable of being easily removed.

c. Where a system terminates on an open weatherdeck and is exposed to heavyseas and spray, a `mushroom top' or equivalent is to be fitted.

d. All weather terminals, other than `mushroom tops' are to be fitted with a sprayeliminator manufactured from materials which will resist corrosion.

e. All weatherdeck ventilation openings which are required to be closed tomaintain the citadel pressure during Condition ALPHA, are to be provided witha butterfly valve sited in the trunk leading from the opening and as close to theship's side as possible. The valve is to have local control and remote control as agroup either on a zonal or ship wide basis, from the SCC or equivalent space.Trunking between the ship's side and the valve is to be gastight.

f. All weatherdeck ventilation openings which are not required to be closed tomaintain Condition ALPHA but are necessary to close to avoid contamination,i.e. contaminated if used spaces, are to be provided with a butterfly valve as atClause 11.5.1.e, but the valve is to be locally controlled from within the citadelonly.

g. In the case of large weatherdeck openings such as Machinery Spaces, whereweight and cost penalties preclude the requirement at Clauses 11.5.1.e and11.5.1.f, then these openings are to be fitted with QAHWC.

h. Facilities are to be provided which will ensure that weatherdeck vent terminalsremain clear of ice and snow when the ship is operating in the coldest climate forwhich it is designed.

11.9 Supply Outlets

a. In normal circumstances the terminal velocity from any supply outlet is not toexceed 3 m/s and the maximum height above the deck to the under�side oftrunking carrying supply terminals is to be 2.4 m.

b. The number and spacing of supply terminals is to ensure that the calculated,required amount of air is evenly distributed throughout the compartment.


March 2000

11.9

c. Textile trunking allows for greater flexibility in air ditribution (See Clause11.2).

11.10 Exhaust/Recirculation Intakes

a. Generally, exhaust/recirculation intakes are to be positioned close to sources ofcontamination where air has to be removed as quickly as possible, e.g. canopiesand hoods over hot equipments, slotted trunks throughout bathrooms and WC,bellmouths adjacent to air�cooled electronic cabinets, etc.

b. In compartments containing heavier than air gases and fumes low level exhaustterminals are to be fitted so that the lowest edge of the terminal is not more than150 mm above the lowest point in the compartment. Where portable deckplates are fitted the lowest point in the compartment is deemed to be under theplates.

c. Inlets in recirculation trunks are to be fitted with dust filters, (See Section 12).

d. All internal exhaust and recirculation inlets are to be fitted with grilles that arereadily accessible and easily removed.

11.11 Miscellaneous Fittings

a. Hinged Watertight Covers (including QAHWC where required) � manufacturedfrom corrosion resistant materials, are to be fitted, where appropriate, toexternal weather openings to give protection against flooding in rough weatherand to prevent the ingress of NBC agents into those compartments outside ofthe citadel boundaries. These are only to be fitted where weight and costpenalties preclude the fitting of butterfly valves.

b. Butterfly Valves are to be installed to ensure the watertight integrity of thevessel and to maintain a gastight citadel boundary. Valves are to be easilyaccessible for operation and maintenance and are to be provided with a local orremote and local control as required by Clauses 11.5.1.e or 11.5.1.f.

c. Air Bleed Valves are to be fitted in Air Locks and Cleansing Stations to provide acontinuous flow of air through these spaces in the `closed down' condition. (SeeSection 9). They are also to be installed as required to ensure zonal andmachinery space pressures are kept within acceptable limits when the vessel isfully `closed down' (See Sections 8 and 9). Performance details of approved airbleed valves are given in Section 9.

d. Fire Flaps are to be fitted in trunks that serve equipments with a high fire riskand at openings in fire barrier bulkheads (See Section 9 and NES 119 Part 1).

e. Filters (See Sections 9 and 12).

f. Flameproof Gauzes are to be fitted in trunking serving compartmentscontaining explosive gases and/or highly flammable stores (See Sections 5 and9).

g. Pressure Relief Valves are to be installed in spaces, catering for three or morepersonnel, that are fitted throughout with supply terminals that can be closedby the occupants. Sufficient valves are to be fitted and adjusted, to ensure thatwith all terminals closed the air supplied to the compartment is at least 50% ofthe designed quantity.


11.10

h. Fittings for Type A and B Screened Compartments:

(1) Where non�metallic trunking penetrates the boundaries of a Type A or Bscreened compartment it is to be fitted with a properly bonded metal wiremesh screen at each penetration;

(2) The wire mesh is to be of an approved type where the crossovers are eitherwelded or soldered and the screen is to be easily removable formaintenance and cleaning;

(3) Wire mesh screens are not required where compartment boundaries arepierced by metallic trunks provided that the trunking is properly bondedat all joints and at all points and at all points of penetration of thecompartment screen;

(4) Wire mesh screens are not required in trunking of any material where thearea of penetration is less than 100 cm2.

i. Fittings for Nuclear Electro�Magnetic Pulse (EMP) � Where a vessel is requiredto be hardened against EMP, metallic trunking that passes in/out of the ship isto be electrically bonded to the ship's structure by a continuous, peripheralweld at the point of penetration.

j. Hose Connections are to be fitted in supply trunks in machinery spaces to allowemergency venting of hot spots and in smoke clearance systems to allowstubborn pockets of smoke to be cleared by hose (See Sections 8, 9 andFigure 11.2).

11.12 Insulation

a. For details of the materials and methods to be used for the thermal and acousticinsulation of air�conditioning and ventilation trunking and fittings seeNES 703.

b. Where it is considered that the use of pre�insulated or double skinnedcommercial trunking systems would be appropriate, certification of theimprovement in acoustic and or thermal insulation performance, relative to themethods described in NES 703, is to be submitted to the MOD for approvalbefore such commercial systems are employed.


March 2000

11.11

92 m

m O

UT

SID

E D

IAM

ET

ER

.

19 m

m

92 m

m D

IA. H

OLE

INT

RU

NK

95 m

m

50 mm 25 mm

13mm

RUBBER SEAL

RINGS FITTED

WITH SUITABLERETAINING CHAIN

COVER TO SCREW ON IN NOT

LESS THAN ONE QUARTER TURNROOFING BOLTS (HEAD INSIDE TRUNK)

TRUNK BY 4 IN No. M5 M.S. GALVANISEDCONNECTION SECURED TO VENTILATION

HOSE, WHEN FITTED, TO BE SECURED BY

WORM DRIVE CLIP OR SIMILAR FASTENING

RINGS FITTEDWITH SUITABLERETAINING CHAIN

ARE APPROXIMATEDIMENSIONS SHOWN

114 mmP.C.D.

Figure 11.2 – Typical Hose Conection For Ventilation Trunks


11.12


March 2000

12.1

12. FILTRATION

Related Documents: BS EN 779, BS 3928, NES 711, NES 713, ASHRAE 52/76;see also Annex A.

12.1 General

a. Filters are to be fitted in:

(1) All ventilation and air�conditioning systems to prevent impurities, thatare generated both inside and outside the vessel, fouling trunking andclogging heaters, coolers, grilles, etc.;

(2) Certain compartments where it is necessary to remove undesirable,noxious fumes and odours from the ship's atmosphere for the benefit ofpersonnel comfort;

(3) CW systems to ensure any impurities introduced into or generated withinthe system are progressively removed and to protect constant flowregulating valves and flow meters from malfunction due to fouling;

(4) Fresh air supply systems serving the citadel to remove nuclear,bacteriological, and chemical contamination.

b. The various types of filters required to be fitted can be categorised under thefollowing headings:

(1) Dust filters;

(2) Odour filters;

(3) Tobacco smoke filters;

(4) Grease filters;

(5) Fresh water filters;

(6) NBC filters.

c. All filters are to be readily accessible and easily removable for cleaning andreplacement. Notices indicating the method and periodicity of cleaning orreplacement are to be fixed adjacent to all filters and filter banks.

12.2 Dust Filters

a. The dust removal efficiency for dust filters for general purposes, is not to be lessthan 95% when tested in accordance with BS EN 779 using ASHRAE 52/76dust.

b. Dust filters are to be manufactured of flame resistant material which, whentested in accordance with NES 711 and NES 713, has a smoke index of less than10 and a toxicity index of less than 5.

c. Dust filters are to be sited as follows:

(1) Air�conditioning Systems:

(a) Where a system has `open' recirculation a dust filter, suitablysecured in a metal frame, is to be positioned at the cooler inletwithin a Central ATU or at the recirculation opening in the case ofCompartment ATU (See Figure 12.1);


12.2

(b) In `open' recirculation systems to Central ATU recirculationopenings in bulkheads are not to be fitted with dust filters except incompartments where significant quantities of dust, that should notbe allowed to migrate into the surrounding passages and lobbies,can be produced, e.g. Shipwright's Workshop;

(c) Where `trunked' recirculation is fitted, each recirculation openingin the trunk is to be protected by a framed dust filter in addition toone sited at the cooler inlet (See Figure 12.2).

(2) Mechanical Supply Systems:

(a) The mechanical supply of fresh air to all air conditionedcompartments within the citadel is to be via AFU that are toincorporate pre�particulate filters, sited at the weather inlets,through which the incoming air is to pass at all times;

(b) Filters are not generally required in mechanical supply systems thatserve normally unmanned spaces inside and outside of citadelboundaries unless trunk mounted heaters are fitted. In such uses adust filter is to be fitted in the trunking as close as possible to theweather inlet.

(3) Mechanical Exhaust System:

(a) All inlets in mechanical exhaust systems serving compartmentswithin citadel boundaries are to be fitted with framed, dust filters;

(b) Dust filters are not normally required in mechanical exhaustsystems that serve spaces outside of the citadel.

(4) Special Requirements:

(a) Compartments such as clean rooms, where there is a requirementfor `absolute' filtration, are to be protected by filters which at thedesigned air flow, ± 10%, are to have an efficiency of 99.997% whenchallenged by particles of 20 to 200 micron with a mass median sizeof 60 micron (See BS 3928), unless specified otherwise incontractual documentation.


March 2000

12.3

5 mm THICK MS GAM FACEPLATE

6 mm THICK FELT FIXED TO FACEPLATE WITH ADHESIVE 3 mm THICK MS CASING GAM

20x20x3 mm ANGLE

M10x35 mm SET PIN WELDED TO ANGLEM10 BRASS WING

NUT

30x30x5 mm ANGLE

DETAIL OF FACEPLATE SECURED TO FILTER CASING

30x30x5 mm ANGLEFILTER CARTRIDGE

6 mm THICK FELT

FILTER CASING 3 mm THICK MS GAM

20x20x3 mm ANGLE

5 mm THICK MS GAM FACEPLATE

AIR FLOW

Figure 12.1 – Typical Dust Filter Mounted In a Trunk


12.4

SECTIONAL ELEVATION

FIXING STRAPS

FILTER

EXPANDED ALUMINIUM TUBE

A

VIEW ON FACE OF GRILLE

LOCKING DEVICECOMPRESSION SPRING

DISTANCE PIECE(EXTRUDED ALUMINIUM) A

PART DETAIL ON A - A

FIXING STRAP POP RIVET

FILTER

RUBBER GASKET

WELDMESH

EXPANDED ALUMINIUM TUBE

ALUMINIUM VANE EXTRUSION ALUMINIUM DISTANCE PIECE

Figure 12.2 – Typical Dust Filter For Openings In Exhaust and Recirculation Trunks


March 2000

12.5

12.3 Odour Filters

a. Odour filters are to be fitted in recirculation trunks that serve bathrooms, WCand galleys. Where possible they are to be fitted within each compartmentserved and are to be sited as close as possible to the point where the recirculationtrunk penetrates the compartment boundary.

b. The filter medium can be either carbon granules, carbon cloth or a combinationof chemicals but filtration performance is not to be effected by the normalmovement and vibration experienced onboard ship in extreme weatherconditions.

c. Under normal ship conditions the life of the filter cartridge, without anydegradation in performance, is to be a minimum of six months.

d. Odour filters are to be good, commercial, marine standards but their efficiencyand effectiveness is to be demonstrated to the satisfaction of the MOD prior toinstallation.

12.4 Tobacco Smoke Filters

a. Tobacco smoke filters, to good, commercial, marine standards, are to be fitted inair�conditioned areas where smoking is allowed, e.g recreation spaces, messdecks, wardroom ante room, etc. When smoking is not allowed but designatedsmoking areas have been set aside, these spaces are to be fitted with a dedicatedexhaust fan in�lieu of the tobacco smoke filters, drawing fresh air from thecitadel and sized to give 20�air changes per hour. The designer is to statewhether this has been treated as a known leakage area when sizing for AFU.

b. Where these units consist of a small fan and replaceable filter element(s),packaged within a decorative casing, an indicator light that is activated whenthe filter(s) requires to be changed is to be provided. To cope with variousconcentrations of smoke and to ensure that the unit can be operated at lowvolume with minimum noise, the fan speed is to be controllable (See Figure 12.3).

c. The ON/OFF and fan speed controls are to be provided locally and the size andnumber of filters installed in a compartment is to be sufficient to cope with a fullcomplement of smokers.

12.5 Grease Filters

a. In galleys and, where appropriate in pantries, grease filters are to be sited overexhaust/recirculation openings in canopies and hoods serving ranges, deep andshallow fryers, and other equipments that could be a source of greasecontamination.

b. Grease filters are to be fitted with an easily removable drip tray to prevent anyexcess oil or grease falling from the filter on to hot equipment or food.

c. The filter element is to be easily removed from the frame and is to be capable ofbeing cleaned with the equipment and facilities normally provided within thecompartment served.


12.6

AIR ENTRY GRILLEFILTER

ELECTRIC SUPPLY

SECURING LUG

OUTLET DUCT LINED WITHACOUSTIC INSULATION

FAN CONTROL

FILTER WARNING LIGHT

FAN

Figure 12.3 – Typical Tobacco Smoke Filter


March 2000

12.7

d. Recirculation and exhaust trunks that carry grease filters are to be fitted withfire flaps (See Section 9).

e. Grease filters to good, commercial, marine standards may be fitted in RN shipssubject to prior MOD approval.

12.6 Fresh Water Filters

a. Two types of fresh water filters are to be fitted in each CW system, viz:

(1) A 5 micron filter is to be fitted in every system to assist in maintaining CWquality standards by continuously treating 5% of the total system flow.These filters are to be capable of being isolated to allow cartridges to bechanged without disruption to the system and an audible or visualwarning that is activated when the filter cartridge is nearing the end of itseffective life is to be provided (See Section 5);

(2) A 60 micron filter is to be positioned in every control panel to protect theflowmeter and constant flow regulating valve(s) and to straighten theflow of water through these items. Isolating valves or a control panelbypass is to be provided to allow maintenance to be carried out withminimum disruption (See Section 6).

12.7 Standard NBC Filters

a. Details of these units are contained in Section 9.


12.8


March 2000

13.1

13. VENTILATION NOISERelated Documents: NES 629, NES 703, NES 810 Part 2, NES 813, NES 832,NES 847; see also Annex A.

13.1 General

a. NES 810 Part 2, states the policy for the `Reduction of Airborne Noise' insurface ships and specifies the Maximum Noise Levels (MNL) that areacceptable within shipboard spaces. Acceptable vibration levels for auxiliarymachinery, including ventilation fans, are given in NES 832.

b. It is emphasised that a compartment MNL is the highest sound pressure level,in dBA, that can be measured within a particular compartment and is thesummation of all noise source transmissions, both internal and external to thatcompartment, generated when the vessel is in a specified operational mode.Although the ventilation/air�conditioning system is a significant, if not theprime, noise source affecting SPL in most spaces, it is not the only one. Fanselection and system design is to ensure that break�out and trunk�borne noiselevels are kept to a minimum and these elements, when combined with otherrelevant noise sources, are not to jeopardize the achievement of acceptableMNL within the compartments served.

c. When designing fan systems, it is to be remembered that total noise generationcan be reduced by employing several small systems, instead of one or two largeones, and by reducing the total pressure, within each system, to the practicalminimum.

13.2 Siting and Mounting of Fans

a. Fans that form part of a Central ATU (See Section 5) are to be sited in dedicatedATU compartments in each fire zone. These ATU compartments are to be linedthroughout with acoustic absorption material faced with perforated metalsheet as specified in NES 703. The thickness of the acoustic absorption lining isto be such that the break�out noise level, i.e. that portion of the sound energygenerated by the fan(s) that is transmitted through the walls of the ATUcompartment, will not exceed 50 dBA.

b. Where fans are an integral part of a Compartment ATU and are sited within amanned compartment (See Section 5), the total ATU package is to be containedin an acoustic enclosure that will provide sufficient attenuation to ensurebreak�out noise levels, through the enclosure walls, will be at least 10 dBAbelow the compartment MNL.

c. Fans serving mechanical supply and exhaust systems both inside and outside ofthe citadel are not to be sited within manned spaces and are to be contained inacoustically lined fan chambers or in acoustic enclosures that will ensure themaximum break�out noise levels from the enclosure will not exceed 50 dBA.

d. All fans are to be supported on rigid structure. Where there is no alternative tositing fans on minor bulkheads or flexible decks appropriate stiffening is to befitted.

e. Where fan chambers and ATU compartments are sited adjacent to operationaland living spaces the associated fans are not to be supported on the divisionalbulkheads.


13.2

f. All fans are to be shock or resiliently mounted and connected to the inlet andoutlet trunking by flexible sleeves (See Section 10).

13.3 Trunking and Fittings

a. The design and installation of trunking and fittings is to ensure that noiselevels, generated and distributed within compartments and throughout thevessel by the air�conditioning and ventilation systems will meet the targetmaximum noise level Permissible Maxima Level (PML) by means, of:

(1) Air velocities not to exceed the maximum specified in Section 4;

(2) The size and numbers of supply and exhaust/recirculation terminalsfitted in any manned compartment are to be as large as practicable toreduce terminal velocities and system pressures;

(3) Abrupt changes of air direction and velocity are to be avoided to minimizethe possibility of excessive turbulence giving rise to vibration andsubsequent noise. Special care is required when designing trunkconnections to fans. The use of aerodynamically smooth curves andtransitions is recommended;

(4) The design and positioning of orifice plates and baffles, required forbalancing the systems, is to be such that noise sources are not created bytheir installation within the ducts.

13.4 System Sound Analysis

a. During the design stage, all air�conditioning and ventilation systems servingmanned spaces and those serving other spaces where there is a possibility thatthe specified MNL may be exceeded, are to be subjected to a sound analysis.

b. This analysis is to assess the magnitude of the contribution made to eachcompartment MNL by trunk borne noise and is to be based upon the soundpower level spectrum of the appropriate fan amended to take account of theattenuation or enhancement of noise levels provided by:

(1) Elements of the trunked system, e.g. bends, take�offs, shape and length oftrunks, etc.;

(2) Thermal insulation;

(3) Type and position of outlets;

(4) The reverberant and direct sound pressure levels within individualcompartments.

c. Within each compartment the SPL (in dBA) generated by theair�conditioning/ventilation system is to be logarithmically coined with allother relevant SPL, including those generated by breakout from ATU/fanenclosures and trunking passing through, and the resultant compared with theappropriate specified MNL. In those cases where the MNL is exceededadditional attenuation is to be included in the system by fitting the mostappropriate acoustic absorption treatment, e.g.:

(1) Lining internal surfaces of the trunking (See NES 703);

(2) Installation of commercial or specifically designed fan silencers;

(3) Introduction of acoustic splitters.


March 2000

13.3

d. Acoustic absorption treatment is not to be fitted in trunking that carries oily,greasy, toxic or other vapours, e.g. galley and machinery space systems unlessfaced internally with a material which will facilitate steam lance cleaning.

e. Where acoustic treatment of the system fails to reduce the compartment noiselevel to the specified MNL, consideration is to be given to lowering the fansound power level by reducing system air velocities and pressures or, wherepossible, by splitting a large system into two, each of which can be served by asmaller, slower speed fan.

13.5 Tests and Trials

a. Noise and vibration tests are to be included in the `Type Testing' and`Production Testing' programmes carried out on all fans prior to theirinstallation at ship (See NES 629 and NES 847). These tests are to be conductedin accordance with NES 847 and NES 813 as appropriate and results are toconfirm that fans comply with the sound criteria specified in the relevant STR(See Section 10). Wherever practicable the maximum Sound Power spectraquoted in the fan STR, especially in the case of `one off' fans, are to reflect theresults of System Sound Analyses to ensure that the Specified MNL areachievable in shipboard conditions.

b. Preliminary and Final Airborne Noise Surveys are to be conducted at shipduring Contractor's Sea Trials and after commissioning, respectively. Wherenoise measurements, recorded during these surveys, indicate thatcompartment MNL are exceeded, the necessary remedial action and reportingis to be undertaken in accordance with NES 810.


13.4


March 2000

14.1

14. DESIGN FOR MAINTENANCE AND SHIP HUSBANDRYRelated Documents: NES 139, NES 703, NES 763; see also Annex A.

14.1 General

a. From the very outset of system and equipment designs it is essential thatconsideration is given to the need to clean, preserve and maintain the totalventilation, air�conditioning and CW system, with its associated equipmentsand fittings, throughout the life of the vessel.

b. The designer is to understand the maintenance requirements implicit in hisdesigns and be aware of the inherent problems associated with carrying out thenecessary routines and procedures onboard RN ships. The design is to ensurethat problem areas are eliminated, or reduced to the minimum possible andmaintenance can be carried out on ship with the most economical use of timeand labour.

c. General guidance on ship husbandry requirements and procedures is given inNES 139 and for ventilation, air�conditioning and CW systems the followingfacilities are to be provided.

d. Internal surfaces of all trunking are to be smooth and free from obstructionsand projections. They are to be left unpainted with the exception of trunksmanufactured of ungalvanized steel and those serving battery charging areaswhich are to be finished in accordance with NES 763.

e. Access into trunking is required to allow the following activities to be effectivelyand efficiently carried out:

(1) Inspections to reliably assess the state of cleanliness of any fitting and/orsection of trunking;

(2) Cleaning of all trunking especially in way of fittings, bends and otherobstructions to the air flow.

f. Access for inspection is to be provided by rapid opening inspection holes that donot require unbolting or bolting up.

g. Access for cleaning is to be provided as follows:

(1) In trunking with the larger side greater than 450 mm, by easily opened,hinged, air tight or watertight covers, as appropriate;

(2) In trunking with the larger side less than 450 mm wide, by removablesections of trunking of between 0.75 m and 2.0 m in length;

(3) Where practicable, removable sections are to be included in recirculationtrunks subjected to heavy contamination, e.g. those from galleys andlaundries.

h. Where removable trunk sections are not practicable access plates that extendthe full width of the trunk and which are as long as possible are to be fitted innon�watertight trunking and in other categories of trunking, the largestpossible hinged, watertight covers are to be fitted.

i. Where both inspection and cleaning access holes are required in the sameposition only the cleaning access is to be fitted.


14.2

j. It is essential that access covers and portable section of trunking are sited wherethey are easily accessible and their removal and access into the trunk is notobstructed by pipes, cables or equipments, etc.

k. The removable sections in non�watertight, non�insulated trunking may bejoined to the adjacent fixed trunks by flexible connections and worm�drive clips.Those in watertight, gastight and insulated trunking and where a high fire riskexists, are to be secured by flanged joints.

l. The type and thickness of material and the spacing of fastenings, used for allcovers and flanges is to reflect the category of the relevant trunking, e.g.watertight, non�watertight, gastight, etc.

m. Where trunking is insulated all covers and removable sections are to be laggedseparately from the main trunking to allow inspection and cleaning routines tobe conducted without the insulation being disturbed and with the minimumexpenditure of time and labour (See NES 703).

n. Bulkhead and deckhead linings are to have easily removable panels or flapsfitted in way of all cleaning and inspection covers and portable trunk sectionsthat are normally hidden. These removable sections of lining are to be ofsufficient size to allow the cleaning procedures to be carried out without undueimpedance. Where flaps are fitted they are to be secured by a simple commonkey.

o. Where the space between trunking and ships structure does not allow access forcleaning and preservation either the ships structure is to be painted prior to theinstallation of the trunking and the space boxed in, or the trunking is to beintegrated with the structure.

14.2 Fittings

a. All fittings and equipments such as fans, coolers, heaters, gauze screens,punkah louvres, grilles, diffusers, etc., are to be capable of being easily removedand replaced for the purposes of cleaning and maintenance.

b. In the case of the larger equipments, removal and maintenance areas into whichpipes, cables and other obstructions must not encroach, are to be identified inthe early stages of the design. In certain spaces where considerable congestionmay occur, such as Central ATU compartments, it may be necessary todemonstrate, at ship or by mock�up, that maintenance routines can be carriedout within the times specified in the ARM requirements.

c. Fittings are to be provided upstream and down�stream of components such asheaters, coolers and gauze screens, to enable the differential pressure acrosseach component to be easily and swiftly measured by manometer. A plate givingthe differential pressure when the component is in pristine condition, is to befirmly fixed to the adjacent trunking.


March 2000

14.3

14.3 Drainage

a. Drains, drain cocks and drain plugs, as appropriate, are to be fitted at positionswhere weather conditions and/or condensation may cause water to collect, asfollows:

(1) Low points in trunking adjacent to weather terminals;

(2) Occasional low points in long, near horizontal runs of trunking;

(3) Low Points in recirculation and exhaust trunks from compartments thatmay contain moist air, e.g. bathrooms, laundries, etc.;

(4) Canopies over steam producing equipments in galleys, laundries, dininghalls, machinery spaces, etc., (See Section 5);

(5) Driptrays and savealls that collect condensation from equipments such ascoolers and dehumidifiers (See Section 6).

14.4 Filters

a. Filters are to be fitted wherever necessary to prevent dirt, debris and greasefrom entering the trunking. Details of the various filters to be installed aregiven in Section 12.

b. It is essential that all filters are readily accessible and adequate, unobstructed,withdrawal/removal space is provided.

c. Filters may be of either the `throw�away' or `easily cleaned' variety but for bothtypes, bags, sufficiently large to completely encase the replaceablecartridge/insert, are to be provided to enable dirty filters to be transportedthrough the ship without shedding dust, grease, etc.

14.5 Water Systems

a. It is essential that after water systems are thoroughly flushed, cleaned andfilled with water of the quality specified (See Sections 6 and 8), that dirt is notgenerated within the system by the erosion and/or corrosion of components orintroduced into it by filling or partially filling with contaminated water.

b. Materials used throughout the systems are to be electrolytically compatible,fluid velocities are to be contained within specified limits, and on no account arecarbon steels, aluminium, or zinc to be used for components and pipes withoutprior approval being given by the MOD.

c. The close circuit water systems are to be continuously filtered by filters andstrainers positioned to protect components such as pumps, flow�meters, etc.,and to ensure that any visible suspended solids are speedily collected andremoved (See Sections 6 and 8 ). The filters and strainers are to be easilyaccessible and their withdrawal is not to be obstructed by other fittings andpipes.


14.4

d. In all essential CW systems and wherever practicable in all other water systems,arrangements are to be provided that will allow the following components to beremoved and replaced for maintenance and cleaning without disturbing theflow of water:

(1) Filter cartridges;

(2) Strainers;

(3) Flowmeters;

(4) Constant flow regulators;

(5) Heat exchangers.

e. Isolating valves, hose connections, drains and air vents are to be provided toenable each branch system, including the relevant heat exchanger, to beisolated from the main system pipework, drained down, back flushed andrefilled with minimal disturbance to other ship activities.

f. In CW systems wherever components and/or pipework cannot be insulated asspecified in NES 703 arrangements in the form of drip trays or savealls are to beprovided for the collection and removal of condensation. Drains, from thedriptrays and savealls, are to be led to the nearest convenient scupper withinthe citadel or to the bilges.


March 2000

15.1

15. INSPECTIONS, TESTS AND TRIALS

Related Documents: BS ISO 4589-2, NES 122 Part 1, NES 123 Part 2, NES 362,NES 629, NES 711, NES 713, NES 810 Part 2, CDE TN 574, CDE TN 595, See AlsoAnnex A.

15.1 General Comments

a. Quality control of ventilation and air�conditioning systems, in terms ofachievement of design temperatures and humidities, the acceptability oftrunked and open air routes and the suitability of selected equipments andfittings, is essential to ensure that the standards, as specified, are achieved bythe systems finally installed.

b. The full programme of quality control activities, related to air�conditioning andventilation systems, can be divided into the following elements:

(1) `Factory Testing' of components, materials and equipments prior toinstallation at ship;

(2) `Inspections' of partially and fully installed air and water systems;

(3) `Testing and Balancing' of air and water systems as finally installed atship;

(4) `Shipboard Trials' in an operational environment.

c. The above Inspections, Tests and Trials, are the responsibility of theShipbuilder or Shiprepairer, whose Quality Plan is to include sufficientcoverage to assure that the design intent has been met. The MOD/DPA, or theiraccredited representatives, are to be given the opportunity of attending andwitnessing any of the programmed Inspections, Tests and Trials of the HVACsystems. Copies of reports associated with the above, are to be forwarded to therelative project section of the MOD/DPA.

15.2 Factory Testing

15.2.1 Type Tests

a. The acceptability of components and equipments such as heaters, coolers,moisture eliminators, filters, pumps, valves, etc., that are `new�to�service', is toconfirmed by `Type Tests' prior to their selection for inclusion in the finaldesign if called for.

b. Type tests are to be carried out on a prototype or representative productionequipment to:

(1) Demonstrate `fitness�for�purpose' of the design;

(2) Establish the range/limits of acceptable performance;

(3) Provide standards against which all subsequent equipments,manufactured to the same design, can be checked.


15.2

c. Where appropriate, testing is to be carried out in accordance with BS, ISO andNES, but where such documents are not available, the method of testing is to beincluded in the STR prepared by the Prime Contractor or his Representative(See Section 3). This STR is to specify acceptable standards of performance andmanufacture that reflect shipboard contractual requirements and are to bepassed to the MOD Project Officer for records and if necessary comment, assoon as completed.

d. In addition to defining performance and manufacturing requirements the STRis, inter�alia, to address the following areas, as appropriate:

(1) Generation or attenuation of air�borne and fluid�borne noise levels;

(2) Resistance to externally generated vibration;

(3) Resistance to shock;

(4) Resistance to external and internal pressures;

(5) Effect of change in attitude due to ship movement;

(6) ARM requirements.

e. Type testing of electric motors and equipments driven by electric motors, suchas fans, compressors, etc., is to be carried out in accordance with NES 629 andguidance for type testing mechanical equipments is given in NES 362.

f. Where components or equipments are manufactured of, or contain,non�metallic materials that are new�to�service, type testing is to include tests todetermine the smoke, toxicity, oxygen and temperature indices of the relevantmaterial (See NES 711, NES 713 and BS ISO 4589�2).

g. Type test results are to be passed to the MOD Project Officer as soon as they areavailable for comment or acceptance.

h. For each new equipment accepted into service a `Configuration DefinitionPackage' is to be prepared by the manufacturer, that is to include:

(1) The equipment STR;

(2) Detailed drawings;

(3) Parts lists;

(4) The Type Test Report prepared in accordance with NES 362;

(5) An ARM Report (where relevant);

(6) Proposals for `Production' testing of subsequent equipments of the samedesign, where appropriate including recommended performancetolerances.

15.3 Production Tests

a. Each equipment and component, or where appropriate a representative sampleof a batch of components, is to be subjected to routine production testing toconfirm that performance standards, established in type tests, are achieved.


March 2000

15.3

b. Requirements for the production testing of electrical and mechanicalequipments are contained in NES 629 and NES 362 respectively.

c. Inspections can best be arranged to cover:

(1) Progress inspections/audits;

(2) NBC filtration inspection and testing;

(3) Final inspections.

15.4 Progress Inspections

a. To be undertaken when all systems are 75% to 80% completed but beforesignificant amounts of the installed trunking, pipework, fittings and openair�routes are obscured by bulkhead linings, false deckheads, etc. This activitymay be progressed by carrying out the inspection in individual fire/smoke zonesas and when convenient.

15.5 NBC Filtration, Inspection and Testing

a. To be undertaken when the NBC fresh air filtration system is fully installed,operating and balanced.

b. Efficiency testing and leak path detection, is the responsibility of theshipbuilder and is to be carried out when the installation is complete. Guidancefor these tests can be found in the CDE TN 574 and CDE TN 595.

c. To minimize disruption to other ship activities, these inspections/tests can becarried out in individual fire/smoke zones as convenient.

15.6 Final Inspection

a. To be undertaken when all systems and associated plant are finally installed,the necessary testing and balancing has been completed satisfactorily and thetotal ship system is operating as designed.

15.7 Testing and Balancing

15.7.1 Air Systems

a. On completion of the installation of the total integrated air system within aparticular fire/smoke zone the individual ventilation, air�conditioning andfresh air systems are to be set�to�work and balanced to ensure design airquantities are achieved, within relevant compartments, with the ship in the`open ship' condition.

b. Prior to balancing, the systems are to be examined to ensure they are free ofaccumulated dust, debris and obstructions that could effect air flows and theyare in the configuration appropriate to operational conditions at sea.

c. During balancing of all AFU, ATU and exhaust systems in that portion of thefire/smoke zone lying within citadel boundaries are to be operated continuouslyso that measured air flows will reflect the dependence of one system uponanother.


15.4

d. Smoke clearance and smoke prevention systems are to be tested and balancedusing simulated smoke generators, when all other systems in the relevantfire/smoke zone are stopped.

e. Outside citadel boundaries, both the supply and exhaust systems serving thesame areas are to be operating when either is being balanced.

f. Machinery space systems are to be tested and balanced in both designconfigurations, i.e. in both the `closed down' and `open ship' conditions (SeeSection 9).

g. The preferred method for adjusting air flows in branch trunks is the use oforifice plates secured between flanges, where the size of opening required togive the correct air flow can be permanently fixed, i.e. when trunking isdismantled for cleaning or maintenance the orifice plates can be easily removedand replaced without disturbing the system balance. Orifice plates are not tocreate additional noise sources within the trunking and it is recommended thatthe excess pressure absorbed by a single plate is limited to 1 mbar.

h. After systems have been balanced and, if necessary rebalanced, the finalmeasured air flows to individual compartments are to lie within the followingtolerances:

(1) Air�conditioning systems and mechanical exhaust systems within thecitadel � Total measured air flow at fans and air quantities delivered toeach compartment are to be within the design figure ± 10%;

(2) Fresh air filtration systems (AFU) � Actual air flow through eachStandard NBC Filter is to be between 270 m3/hr and 330 m3/hr. Totalmeasured air flow through AFU and distribution to each terminal is to bewithin the design figures ± 10%;

(3) Mechanical supply and exhaust systems outside of the citadel � Totalmeasured air flow at each fan is to lie within 125% and 90% of the designfigure. The air quantity delivered to each branch carrying terminals is notto be less than the design figure minus 10%. Where a compartment isserved by both mechanical supply and exhaust systems, the application ofthese tolerances is not to create an over or under pressure within thecompartment relative to the surrounding spaces.

15.8 Air Test Reports

a. A comprehensive Test Form report that provides the following information is tobe prepared for each system:

(1) General Details:

(a) Name of vessel;

(b) Date of test;

(c) Type of system, e.g. essential air�conditioning, filtered fresh air,mechanical exhaust from citadel, etc.


March 2000

15.5

(2) Fan Details:

(a) Location and control marking;

(b) Type and size;

(c) Manufacturers name and identification number(s);

(d) Design and measured performance in terms of total air volume andtotal pressure (For air�conditioning systems the total air volume isto be broken down into supply, fresh air and recirculatedquantities);

(e) Rated and measured volts, amps and revs.

(3) Air Distribution:

(a) Name and position of all compartments served;

(b) Design and measured total air quantities to each compartment.Measurements are to be taken within each branch trunk serving thecompartment. Summation of air volumes at individualoutlets/inlets is not acceptable.

(4) Air Pressures:

(a) Total Water Gauge (WG) at fan inlet and outlet;

(b) Total WG at branch take�offs;

(c) Static WG at first and last terminals in all branch trunks;

(d) Differential pressure across obstructions to air flow in trunks, e.g.coolers, heaters and filters.

b. Each report is to include a single line drawing of the system tested thatidentifies:

(1) Main and branch trunk sizes and routes;

(2) Open recirculation routes;

(3) The position of all equipments and fittings;

(4) Natural ventilation openings;

(5) Test positions for measuring air quantities and pressures;

(6) Size and position of orifice plates.

15.9 Water Systems

a. On completion of the installation of a CW System the following test routine is tobe initiated:

(1) Examination to confirm all pipe�work, fittings, controls, equipment andplant are installed in accordance with approved drawings and areoperating correctly;


15.6

(2) Pressure test conducted, if necessary with heat exchangers isolated andconstant flow regulators removed, to confirm that pipework canwithstand an internal pressure of 1.5 times the design working pressure.The test pressure is to be maintained for at least one hour;

(3) System cleaned by flushing and filled with water to the specifiedstandards (See Section 6);

(4) System configured for normal operation with thermostatic valves gaggedopen and constant flow regulators in place;

(5) Where a system includes more than one pump or CWP, the water flows areto be adjusted to ensure that equal flows are obtained through all pumpsand plants, in all configurations;

(6) Water flow to each heat exchanger and, where appropriate, eachelectronic cabinet, to be measured and recorded. If necessary, remedialaction is to be taken to ensure actual flows are within the design figure of± 10%;

(7) After balancing, thermostatic valves are to be reset to control the flowsthrough relevant coolers.

b. Where, in certain compartments, hot water has been selected as the heatingmedium, the testing is to follow the same routine as for CW systems.

c. For all water systems, a comprehensive report is to be prepared that:

(1) Confirms testing and balancing was carried out in accordance with theabove routine;

(2) Identifies all outstanding discrepancies between approved drawings andactual installation at ship;

(3) Describes all pressure and flow tests undertaken;

(4) Lists all measured quantities against design quantities in tabular form;

(5) Indicates any measured flows outside of specified tolerances, withrecommendations for remedial action;

(6) Includes a single line, planimetric drawing of the relevant system thatshows:

(a) Sizes and routes of all pipework;

(b) All plant, pumps, equipments, heat exchangers, controls, fittings,etc.;

(c) Valve status during testing, i.e. fully open, adjusted or shut;

(d) Test points and measured quantities at each point.


March 2000

15.7

15.10 Zonal Pressures Tests

a. When all systems within a fire/smoke zone have been satisfactorily balanced,the portion of the zone that lies within the citadel is to be isolated by securingthe relevant zonal and citadel boundaries and, with all systems and Air Locksoperating as in the `closed down' condition, measurements are to be taken of theair pressure within the zone, relative to the external atmosphere.

b. To be acceptable, zonal pressures are to be within 5 mbar to 8 mbar aboveatmospheric and within ± 0.5 mbar of the pressures measured in adjacent zones(See Section 9).

c. Once zonal pressures have been adjusted to within the specified tolerances andwith zonal and citadel boundaries still secured, the purging air flows throughAir Locks and Cleansing Stations are to be measured and if necessary adjustedto satisfy the design figure ± 10%.

d. Zonal pressure tests are to be carried out after the citadel boundaries have beentested and, where necessary, all defects made good. If circumstances allow, teststo determine zonal pressures, Air Lock and Cleansing Station purging and toconfirm citadel boundaries, may be progressed together.

15.11 Habitability Trials

a. Habitability trials are to be conducted simultaneously with equipment trials ingalleys and laundries in accordance with NES 122 Part 1 and NES 123 Part 2respectively.

b. Prior to these trials being undertaken, all ventilation and air�conditioningsystems within the particular fire/smoke zone are to have been satisfactorilytested and balanced, relevant CWP set to work and the associated CW systemstested and balanced.

c. Throughout the trial the following conditions are to apply:

(1) All mechanical exhaust, fresh air/filtration and air�conditioning systems,within the particular zone, operating;

(2) The appropriate CWP operating;

(3) CW flows and temperatures to coolers serving the compartments beingtested, are within specified tolerances.

d. During the habitability trial the following information is to be recorded and,accompanied by an outline plan of the compartment and surrounding spacesshowing equipment sites and positions at which temperature andpsychrometric readings were taken, forwarded to the MOD/DPA ProjectOfficer.

(1) Name and number of vessel;

(2) Date and time of trial;

(3) Half hourly temperatures at working positions for all items of equipment.Thermometers/thermocouples to record these temperatures are to behung at head height;


15.8

(4) Half hourly contact temperatures, within the compartment, and anydivisional bulkheads or decks;

(5) Half hourly wet and dry bulb temperatures at the following positions:

(a) In fresh/filtered air trunk just prior to its intersection with therecirculation trunk;

(b) In the main recirculation trunk just prior to its intersection with thefresh/filtered air trunk;

(c) At the first and last terminal in each supply branch trunk;

(d) Within recirculation trunking at positions as near as practicable toeach canopy;

(e) Within mechanical exhaust trunk serving drying tumblers(Laundries only);

(f) Local `hot�spots' in front of heat producing equipments, i.e. ranges,washing machines, ovens, etc.;

(g) In all surrounding spaces.

(6) Air flows in m3/s in all main distribution, fresh/filtered air, recirculationand, where fitted, mechanical exhaust trunks.

15.12 Performance Trials

a. Performance Trials are to be conducted to assess the efficiency of the total shipsystem under operational conditions in both Tropical and Arctic environmentsfor which the vessel has been designed. Each trial is to be undertaken on arepresentative vessel of a class as soon as possible after the First�of�Class iscommissioned. These trials are the responsibility of the lead shipbuilder andare to be conducted by him. Every opportunity is to be given for MOD personnelto attend and witness these trials.

b. These trials are to be conducted, at sea in an environment that is as near aspossible to the relevant extreme design condition, over a period of several daysor possibly weeks, depending on the size of vessel and the number and extent ofthe systems involved.

c. Tropical Performance Trials are to include the following elements, subject tothe ship's operational commitments:

(1) Air�conditioning trials on each individual essential heat exchanger and itsassociated air system with the relevant compartments fully manned andall equipments operating normally;

(2) Air�conditioning trials on each individual non�essential heat exchangerand its associated air system with the relevant compartments fullyoccupied and all equipments that are potential heat sources, operatingnormally;


March 2000

15.9

(3) Air�conditioning trials on selected essential heat exchangers and theassociated air systems, in each fire/smoke zone, under emergency ormaintenance configurations, i.e. with essential CWP replaced byCW/tepid water heat exchanger and also with essential CW systemsupplied totally from non�essential plants and pumps;

(4) Air flow, temperature and humidity checks at regular intervals in allmechanical and naturally ventilated spaces over a representativeoperational period;

(5) Continuous recording of temperature and relative humidity in selectedspaces, i.e. laundry, galley, dining hall, bathroom, etc.;

(6) Machinery space trials in `open ship' condition;

(7) Machinery space trials in `closed down' condition with dedicated AFUoperating and cooling effected by the standby CWP;

(8) Trials under `closed down' conditions with fire/smoke zone and citadelboundaries fully secured and Air Lock/Cleansing Station disciplinesimposed. In this condition, as circumstances allow, checks are to be madeon:

(a) Purging rates through Air Locks and Cleansing Stations;

(b) Pressures within fire/smoke zones;

(c) Accessibility between zones;

(d) Effect on adjacent zones when individual zones are breached by theuse of smoke clearance systems;

(e) Habitability checks at shelter stations when fully manned;

(9) Condition and configuration of all operating CWP throughout the totalperformance trials programme (hourly readings).

d. Arctic Performance Trials are to follow a similar programme to that describedabove but air and CW flows are to be adjusted, compartments manned,equipments operated and heating systems initiated to comply with the designconditions relevant to the prevailing weather.

e. `Closed down' trials (See Para 15.12c.(8)) may be carried out during eitherArctic or Tropical Performance Trials. They need not be repeated.

f. At the completion of each Performance Trial, a comprehensive report is to beprepared. This report is to indicate the climatic conditions encountered daily,describe all trials undertaken giving dates and times, identify shortcomings andproblem areas with recommendations for remedial action or design changes infuture ships, and present all trials results in an easily understandable andlogical manner using standard test sheets and tabular statements as necessary.

15.13 Airborne Noise Trials/Surveys

a. Airborne noise surveys are to be carried out at sea during Contractors Sea Trialsand as soon as possible after commissioning. They are to be conducted andreported in accordance with NES 810 Part 2.


15.10

15.14 Instruments

a. All instruments used for measuring air and water flows, air and waterpressures, temperatures, humidities, etc., when carrying out any of theinspections and trials described above are to be of a type approved by the MOD.At the time of use they are to be within three years of their latest calibration by aNAMAS accredited laboratory. Quality control of ventilation andair�conditioning systems, in terms of achievement of design temperatures andhumidities, the acceptability of trunked and open air routes and the suitabilityof selected equipments and fittings, is essential to ensure that the standards, asspecified, are achieved by the systems finally installed.


March 2000

ANNEX AA.1

ANNEX A.

RELATED DOCUMENTS

A.1 The following documents and publications are referred to in this NES:

SI 1984 Nº 1218 The Merchant Shipping (Fire Protection) RegulationsStatutory Instrument 1984 No 1218

HSWA Health and Safety at Work Act

COSHH Regulations1992

Control of Substances Hazardous to Health

ISO 5801 Industrial Fans�Performance Testing Using StandardizedAirways

ISO 7547 Air�conditioning and ventilation of accommodation spaceson board ships�Design conditions and basis of calculations

ISO 9785 Shipbuilding�Ventilation of cargo spaces where internalcombustion engine vehicles may be driven�Calculation oftheoretical total airflow required

BS EN 779 Particulate Air Filters for General Ventilation

BS 848 Fans for general purposes

Part 1: Method of testing performance

Part 6: Method of measurement of fan vibration

BS 1553 Specification for graphical symbols for generalengineeringPart 1 Piping systems and plantPart 3 Graphical symbols for compressing plant

BS 3928 Method for sodium flame test for air filters

BS ISO 4589�2 Plastics: Ambient Temperature Test

JSP 430 MOD Ship Safety Management System Handbook.

STANAG 4447 Performance Specification for a Ships NBC Air Filter

NES 101 Requirements For Design and Fitting Out of Workshops,Maintenance Spaces and Engineering Stores for HMSurface Ships

Part 2: Specific Requirements

NES 111 Requirements for the Insulation and Fittings for theRefrigeration Spaces in Surface Ships and Submarines

NES 118 Materiel Requirements for the NBC Defence of SurfaceShips including RFAs

NES 119 The Requirements for Fire Protection and DamageControl for Surface Ships Part 1 Policy for Surface ShipsPart 3 Surface and Submarine Equipment

NES 122 Catering EquipmentPart 1 Equipment to MOD(PE) Design Standards


ANNEX A A.2

NES 123 Requirements for Laundries and AssociatedCompartments

Part 1: Laundries and Associated Compartments

Part 2: Laundry Machinery, Equipment & Fittings

NES 139 Code of Practice for Ship Husbandry

NES 155 Requirements for Structural Practices in Steel SurfaceShipsPart 1 General requirements

NES 183 Requirements for the Construction and SystemArrangements in Magazines and Weapon StowageCompartments

Part 1: HM Surface Ships

NES 329 Requirements for Heat Exchangers

NES 341 Requirements for Cleaning of Items, Components andEquipment for Fluid Systems

Part 1: Cleaning

NES 345 Requirements for Flexible Rubber Pipe Assemblies andBellows for use in Systems from Vacuum to 10 bar

NES 360 List of Preferred Standard Valves�Metric (Low pressure)

NES 362 Type and Production Testing of Mechanical Equipment

NES 501 General Requirements for the Design of Electrotechnicaland Naval Weapon Equipment

NES 519 Requirements and Safety Regulations for ElectricalEquipment and Installations Fitted in Magazines,Submarine Weapon Stowage Compartments AdjacentCompartments and Designated Danger Areas

NES 529 Nuclear Hardening Guide

Part 2: Electrical Installation in HM Surface Ships

NES 593 List of Approved Electrical Fittings for use in Magazines,Cargo Holds and Weapon Stowage Compartments

NES 596 Preferred Range of Heating and ThermostaticComponents

NES 627 Requirements for General Application to RotatingElectrical Machinery

NES 628 Requirements for Preparation of Drawings for RotatingElectrical Machinery

NES 629 Requirements for Testing of Rotating ElectricalMachinery

NES 703 Thermal and Acoustic Insulation of Hull and Machinery

NES 705 Selection of Materials on the Basis of thier FireCharacteristics

NES 707 Symbols and AbbreviationsPart 1 Guide to the General Use of SymbolsPart 2 Guide to Abbreviations & System Code Letters

NES 710 Fluid Systems General Requirements


March 2000

ANNEX AA.3

NES 711 Determination of the Smoke Index of the Products ofCombustion from Small Specimens of Material

NES 713 Determination of the Toxicity Index of the Products ofCombustion from Small Specimens of Materials

NES 728 Domestic Hot and Cold Fresh Water Systems

NES 763 Requirements for the Preservation and Painting ofCompartments in Surface Ships

NES 809 Guide to the Reduction of Radar Cross Section of SurfaceShipsPart 1 Hull Superstructure and Above Deck MountedEquipment

NES 810 Design Guide for the Reduction of Acoustic Noise inSurface Ships

Part 2: Reduction of Internal Airborne Noise (Ltd Circ)

NES 813 Requirements for Structure Borne Vibration Testing ofWarship Equipment

NES 832 Airborne Noise and Vibration Levels for AuxiliaryMachinery

NES 847 Airborne Noise Tests for Equipments and Machinery tobe Installed in HM Ships, Submarines and Royal FleetAuxiliary

NES 1004 Requirements for the Design and Testing of Equipmentsto Meet Environmental Conditions

BR 1754 Safety Regulations for Storing and Handling Petroleum,Oils, Lubricants and Certain Other Hazardous Stores inHM Ships

BR 2170 Ship NBCD Manual

BR 6590(002) No 6 MK1 and No 7 MK1 NBC Filter Units

SSCF4 Application for Concession of Departures from NavalMagazine and Explosive Regulations

STR 422/04/08/231a Electric Heaters for Air�conditioning in HM Ships

NATO AC 225(Phase VII/NSPWGE�1)

Design Guide for a NBC Filter Station

CDE TN 574 An In�Situ Test Method for Particle Filter Systems

CDE TN 595 Test Procedure for the Non�destructive Testing ofAbsorbent Filters

ASHRAE 52/76 Dust Control and Filtration


ANNEX A A.4


March 2000

ANNEX BB.1

ANNEX B.

ABBREVIATIONS AND DEFINITIONS

B.1 For the purpose of this NES the following abbreviations apply:

ABV Automatic Bleed Valves

AFU Air Filtration Unit

ARM Availability, Reliability and Maintainability

ASHRAE American Society of Heating, Refrigeration and Allied Engineers

ATU Air Treament Unit

BA Breathing Apperatus

BS British Standards

BTM Bromotrifluoromethane (Halon 1301)

BSRIA Building Services Research Industrial Association

CDE Chemical Defence Establishment

CIBSE Civil Institute Building Services Engineering

COSHH Control of Substances Hazardous to Health

CW Chilled Water

CWP Chilled Water Plant

dBA Decibel A scale

dBW Decibel Watt

DA Design Authority

DETR Department of the Environment, Transport and The Regions

Dp Differential Pressure

EMP Electro�Magnetic Pulse

EOS Emergency Operating Stations

ET Effective Temperature

ESDM Engineering System Design Methods

FW Fresh Water

GAM Galvanized After Manufacture

GRP Glass Reinforced Plastic

HSWA Health and Safety at Work Act

HVAC Heating Ventilation and Air�Conditioning

HQ Headquarters

ISO International Standards Organisation

LEV Local Exhaust Ventilation

MCR Machinery Control Room

MNL Maximum Noise Levels

MOD Ministry of Defence


ANNEX B B.2

MS Mild Steel

MTBF Mean Time Between Failure

MTTR Mean Time to Repair

MWV Minor War Vessel

NBC Nuclear Biological and Chemical

NBCD Nuclear Biological and Chemical Defence

NBCW Nuclear Bacteriological and Chemical Warfare

NSN Nato Stock Numbers

NSR Naval Staff Requirement

NST Naval Staff Target

PML Permissable Maximum Level

QAHWC Quick Acting Hinged Watertight Covers

QAR Quality Assurance Representative

RCS Radar Cross Section

RFA Royal Fleet Auxiliary

RH Relative Humidity

RN Royal Navy

SCC Ship Control Centre

SDN Service Drawing Number

SDNR Screw Down Non�Return

SHR Sensible Heat Ratio

SPL Sound Pressure Level

SR(S) Staff Requirments (Sea)

STR Statement of Technical Requirements

SW Sea Water

TACS Total Atmospheric Control System

TES Technical Equipment Specifications

TN Technical Note

WG Water Gauge

WL Water Level

B.2 For the purposes of this NES the following definitions apply:

Air�conditioning The control of the physical and chemical properties of air inan enclosed space to within specified limits.

Air Filtration Unit (AFU) A structure containing pre�particulate filters, Standard NBCFilters, fan(s), and possibly dehumidification equipmentthat may be free�standing or integrated with the ship'sstructure.

Air Treatment Unit(ATU)

An engineered package of heater, cooler, particulate filterand fan that may be housed in a special compartment withother ATU or contained, as a separate item, in an acousticenclosure within the particular compartment being served.


March 2000

ANNEX BB.3

Arctic Conditions The coldest, continuous weather conditions that are to begenerally allowed for.

Chilled Water Plant(CWP)

A main refrigeration unit comprised of compressor,condenser, evaporator and associated pump(s), etc., which isused to cool water delivered from heat exchangers servingcompartments and electronic cabinets.

Constant Orifice Line A graphical representation of the variation in total systemresistance when various air volumes are passed through aparticular trunk system. On a logarithmic graph it isdepicted as a straight line having a two in one slope, i.e.pressure varies as the square of the volume.

Design Authority The approved Firm, Establishment or Branch responsiblefor the detailed design of materiel to approved specificationsand authorised to sign a Certificate of Design or to certifysealed drawings.

Effective Temperature(ET)

An empirical index of comfort that takes account of dry bulband wet bulb temperatures and air movement. In this NESthe Effective Temperatures quoted assume still air.

Essential Compartments Compartments that contain machinery and/or equipment,the loss or malfunction of which would immediately anddirectly affect the ship's operational capability, e.g. weaponscompartments, operations room, MCR, communicationsoffice, etc.

Extreme TropicalConditions

The hottest, continuous weather conditions to be allowed forin special cases.

Fire/Smoke Zone A portion of the ship contained within smoke�tightbulkheads extending from keel to the uppermost part of thevessel's superstructure in which the majority of essentialservices are autonomous.

Group System A system where a mixture of fresh and recirculated air iscooled and/or heated by an ATU prior to being distributed toone or more compartments.

Hazardous Compartment A compartment where noxious, toxic, explosive and/orflammable gases and vapours may be produced by normalfunctions.

Latent Heat Heat added or removed during a change of state, thetemperature remaining constant.

Moisture or SprayEliminator

A grid arrangement of parallel corrugated plates to arrestand drain moisture droplets from air passing through. Themoisture source can be condensation at cooling coils orexternal weather conditions.

NBC Citadel That portion of the vessel, bounded by gastight bulkheadsand decks, that can be conditionally pressurized aboveexternal atmospheric pressure by the introduction ofuncontaminated fresh air.

Non�essentialCompartments

Compartments containing machinery and/or equipment, theloss or malfunction of which would not directly affect theship's operational capability, e.g. accommodation, galley,laundry, storerooms, etc.


ANNEX B B.4

Sensible Heat Heat that directly and reversibly affects the temperature ofa substance.

Sensible Heat Ratio The ratio of sensible heat gain to latent heat gain.

Standard NBC Filter A radial particulate and vapour filter manufactured to MODspecifications and capable of removing nuclear, biologicaland chemical agents from incoming air.

Subarctic Conditions The coldest, continuous weather conditions to be allowed forin special cases.

Temperate SummerConditions

The hottest, continuous weather conditions to be allowed forin temperate climates.

Temperate WinterConditions

The coldest, continuous weather conditions to be allowed forin temperate climates.

Total Heat The sum of sensible and latent heat.

Tropical Conditions The hottest, continuous weather conditions to be generallyallowed for.

Ventilation Sub�zone A ventilation subdivision within the main fire/smoke zone asan aid to smoke control, and could entail the isolation of asingle ATU.


March 2000

ANNEX CC.1

ANNEX C.

PROCUREMENT CHECK LISTThis NES contains no Procurement Check List information.


ANNEX C C.2


March 2000

INDEX 1

ALPHABETICAL INDEX

(Note: Page numbers are given)

AAbbreviations and Definitions, B.1

Air Distribution Systems, 5.1, 5.21

Air Balance Diagrams, 5.23

Air-conditioning Arrangements, 5.2

ATU Controls, 5.4

Bathrooms and WCs, 5.7Bathrooms, 5.9

General Requirements, 5.7WCs and Urinals, 5.8

Battery Charging Rooms and SpacesContaining Battery Charging Facilities,5.18

Central ATUs, 5.3

Compartment ATUs, 5.3

Compartments Containing Dangerous orNoxious Gases, 5.17

General Requirements, 5.17

Compartments Containing Petroleum,Oils, Lubricants, etc., 5.20

Configuration No 1 (Full fresh aircooling), 5.6

Configuration No 2 (Semi-recirculation),5.6

Dental Surgery, 5.7

Conversion Machinery Rooms, 5.14

Design Objective, 5.1

Dry Provision Room, 5.23

Drying Rooms, 5.12

Electrical Switchboard Rooms, 5.23

Emergency Generator Compartment, 5.23

Galleys and Associated Spaces, 5.10Galley, Servery and Scullery, 5.10Miscellaneous, 5.11

Pantries and Pantry/Serveries, 5.11


Hangars, 5.21

HP Air Compressors, 5.21

Hydrogen and Acetylene StorageCompartments, 5.19

Laundries and Associated Spaces, 5.12

Magazines, 5.15

Medical Spaces, 5.5Sick Bays, 5.5

Paint Rooms, Paint Stores and FlammableStores, 5.19

Refrigeration Machinery Compartments,Refrigeration Machinery and BottleStowages for Heavier than Air Gases,5.18

Sewage Treatment Spaces, 5.14

Special Requirements, 5.4Accommodation and Recreation

Spaces, 5.4Operational Spaces, 5.4

Steering Gear (Secondary SteeringPosition), 5.23

Storerooms, 5.14

Vehicle Decks, 5.22

Workshops, 5.13

CCooling Systems, 6.1

Air Treatment Units, 6.9

Chilled Water Unit Coolers, 6.9

Chilled Water/Air Heat Exchangers(Coolers), 6.6

Cleanliness, 6.7

Compartment Cooling, 6.9

Dehumidifiers and Condensation Control,6.11

Demarcation, 6.11

Design Principles, 6.1

Equipment Cooling, 6.10

Free Standing Air-conditioning Units,6.10

Insulation, 6.11

Materials, 6.7

Statement of Style, 6.1

System Arangement and Components, 6.5

System Reliability, 6.11


INDEX 2

Water Quality, 6.8

DDesign Data, 4.1

Air Distribution Systems, 4.4Air Velocities, 4.4Fresh/Filtered Air Requirement, 4.5Standard NBC Filters, 4.6

Chilled Water Systems, 4.7Design Margins, 4.7

Chilled Water Temperatures, 4.7

Cooling and Heating Assumptions, 4.2Cooling conditions, 4.2Heating conditions, 4.3

Environmental Design Conditions, 4.1External Temperatures (Cold

Climates), 4.1External Temperatures (Hot

Climates), 4.1Internal Temperatures -

Air-conditioned Spaces, 4.1All Cold Climates, 4.1Temperate Summer, 4.1Tropics, 4.1

Internal Temperatures-VentilatedSpaces, 4.2

All Cold Climates, 4.2All Hot Climates, 4.2

Heating Systems, 4.6

Pressurization, 4.6Citadel and Zones, 4.6

Machinery Spaces, 4.6

Relative Humidity, 4.4

Total Heat Transfer Coefficient `k', 4.3

Velocities and Pipe Size, 4.8

Design For Maintenance And ShipHusbandry, 14.1

Drainage, 14.3

Filters, 14.3

Fittings, 14.2

General , 14.1

Water Systems, 14.3

Design Procedure, 3.1

Concept Studies, 3.1

Design Leading to Contract Definition, 3.4

Detailed Design, 3.4

Feasibility, 3.1

Design Requirements/Criteria, 2.1

Air-conditioning and VentilationSystems, 2.4

Chilled Water Systems, 2.6

**Environment Conditions**, 2.1


Local Exhaust Ventilation Systems, 2.7

Machinery Spaces, 2.5

Smoke Clearance, 2.5

FFans, 10.1

Fans

Availability, Reliability andMaintainability, 10.3

Construction, 10.1

Fan Markings, 10.5

Fan Selection, 10.1

Fan Testing, 10.3

Materials, 10.1

Motors, 10.3

Mounting and Siting of Fans, 10.4

Noise, 10.3

Shock, 10.3

Special Fans, 10.5

Vibration (Externally Generated), 10.3

Vibration (Self Generated), 10.3

Filtration, 12.1

Dust Filters, 12.1

Fresh Water Filters, 12.7

General, 12.1

Grease Filters, 12.5

Odour Filters, 12.5

Standard NBC Filters, 12.7

Tobacco Smoke Filters, 12.5

GGeneral Information, 1.1

Climatic Conditions, 1.1Cold Weather, 1.1


March 2000

INDEX 3

Hot Weather, 1.1

Design Conditions, 1.1

Operational States, 1.2

Ship Subdivision, 1.2

HHeating Systems, 7.1

Air-conditioned Compartments, 7.1

Classification of Heaters, 7.2Reheaters, 7.3Supplementary/Boost Heaters, 7.3

Compartments Outside the NBC Citadel(Ex Machinery Spaces), 7.2

Electric Heater Controls, 7.4

Fresh Air, 7.2


Hazardous Compartments Within theNBC Citadel, 7.2

Heater Controls, 7.3Positioning of Sensors, 7.3

Heater Markings, 7.7

Hot Water Heater Controls, 7.4

Humidifiers, 7.7

Space Heating, 7.5

Category 1, 7.5Category 2, 7.5Category 3, 7.6Electric Heater Panels, 7.6

Fan Assisted Electric Heaters, 7.6Hot Water Radiators, 7.6Hot Water Systems, 7.6Types of Space Heaters, 7.6

Trunk Mounted Heaters, 7.5Electric Heaters, 7.5Hot Water Heaters, 7.5

IINSPECTIONS, TESTS AND TRIALS, 15.1

Air Systems, 15.3

Air Test Reports, 15.4

Airborne Noise Trials/Surveys, 15.9

Factory Testing, 15.1Type Tests, 15.1

Final Inspection, 15.3

General Comments, 15.1

Habitability Trials, 15.7

Instruments, 15.10

NBC Filtration, Inspection and Testing,15.3

Performance Trials, 15.8

Production Tests, 15.2

Progress Inspections, 15.3

Water Systems, 15.5

Zonal Pressures Tests, 15.7

MMachinery Spaces, 8.1

Air Systems, 8.2

Cooling, 8.1

General, 8.3

Heating, 8.3

Machinery Space Ventilation Trials, 8.4

Pressurisation, 8.2

System Design, 8.1Action State/Closed Down Condition,

8.1Cruise State/Open Ship Condition, 8.1

NNBCD & Fire Fighting Arrangements, 9.1

Air Filtration Units and NBC Filters, 9.3

Air Locks, 9.5

Citadel Pressurisation, 9.1

Cleansing Station, 9.6

Fire Fighting and Fire Precautions, 9.6

Fire Fighting Subdivision, 9.1

Fire Flaps, 9.11

Fire Precautions in Royal Fleet AuxiliaryVessels, 9.14

High Risk Areas, Galleys, 9.10

Highly Flammable Stores and ExplosiveGases, 9.11


INDEX 4

Intake of Ambient Air, 9.2Calculated Uncontrolled Leakages, 9.2

Control Of CO2, 9.3

Known Controlled Leakages, 9.3

NBCD Subdivision, 9.1

NBCD Ventilation Board, 9.14

Purging, 9.5

Smoke Clearance/Containment - Policy(Surface Ships), 9.7

TTable of Contents, vii

Trunking and Fitting

Exhaust/Recirculation Intakes, 11.9

Gastight and Structural Trunks andTrunks Subjected to Rough Usage orHigh Fire Risk Including SmokeRemoval Systems, 11.4

General, 11.1

Insulation, 11.10

Miscellaneous Fittings, 11.9

Non-Watertight, Non-Gastight Trunks,11.1

Supply Outlets, 11.8

Textile Ventilation Trunking, 11.2Advantages, 11.3

Cleaning, 11.3Draught Free, 11.3Economic Storage & Transportation,

11.3Efficient Air Distribution, 11.3Fire Retardency and Toxicity, 11.4Flexible Mounting, 11.3Low Weight, 11.3Recirculation Ducting, 11.3Reduced Air Noise, 11.3Repair and Modifications, 11.3

Disadvantages, 11.4

Trunking - Associated Fittings, 11.8

Vulnerability, 11.6

Watertight Trunks, 11.5Trunk Installation, 11.5

Weather Terminals, 11.8

VVentilation Noise, 13.1

General, 13.1

Siting and Mounting of Fans, 13.1

System Sound Analysis, 13.2

Tests and Trials, 13.3

Trunking and Fittings, 13.2

Inside Rear Cover

© Crown Copyright 2000

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