NES 603 Guide to the Policy, Design and Installation of Fire Detection Systems in Ships Category 1

Requirements for the Policy, Design andInstallation of Fire Detection Systems in

Ships

Ministry of Defence INTERIM Defence Standard 02-603 (NES 603)

Issue 2 Publication Date 1 June 2001

Category 1

DStanPlease note that this is an INTERIM Defence Standard. For further information please see the "INTERIM DEFENCE STANDARD - INVITATION TO COMMENT" on the third page of this document.

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 02-603/Issue 1 1 April 2000NES 603 Issue 1 April 1990

DefenceMR J KNOTTSTAN SPM 5

ProcurementAgency

D/DStan/69/2/603/Def Stan 02-603 Issue 2 Defence StandardizationRm 1138Kentigern House65 Brown stGlasgow G2 8EXDirect line: 0141 224 2332Switchboard: 0141 224 2531Facsimile: 0141 224 2503

e-mail: [email protected] [email protected]

Your Ref:Our Ref: DStan/69/2/603Date:

INTERIM DEFENCE STANDARD (FORMER NES) - INVITATION TO COMMENT

Defence Standard Number: 02-603 (NES 603) Issue 2 INTERIM

Title: Requirements for the Policy, Design and Installation of Fire Detection Systems in Ships

The above Defence Standard has been published as an INTERIM Standard. Interim Defence Standardsare suitable to be called up in contracts and have the same legal status as full standards. In addition thisstandard is considered to be technically correct, but it is necessary to use it and get user feed back on itssuitability before reissue as a full standard. Interim Standards are reviewed after a year and wherenecessary amended. They are then normally reissued as full standards. Users are therefore invited toforward any information or comment and experience on the application of this standard. These will becollated and forwarded to the sponsor to aid amendment and issue of a final version.

The purpose of this form therefore is to solicit any beneficial and constructive comment that will assistthe author and/or working group to review the INTERIM Standard prior to it being converted to a fullStandard.

Comments are to be entered below and any additional pertinent data which may also be of use inimproving the Standard should be attached to this form and returned to the above address.No acknowledgement to comments received will normally be issued.

NAME: J KNOTT SIGNATURE: J Knott BRANCH: PDG/DSTAN SPM 51. Does any part of the Standard create problems or require interpretation:

YES NO If yes state under section 3: a. the clause number(s) and wording; b. the recommendation for correcting the deficiencies.

DPA

AN EXECUTIVE AGENCY OF THE MINISTRY OF DEFENCE

2. Is the Defence Standard restrictive:

YES NO If yes state in what way under section 3.

3. Comments, general or any requirement considered too rigid:

Page Clause Comments Proposed Solution

4. I/We agree that this Draft Standard, subject to my/our comments being taken into consideration,when published in final form will cover my/our requirements in full. Should you find my/our commentsat variance with the majority, I/we shall be glad of the opportunity to enlarge upon them before finalpublication.

Signature.................................................................Representing.................................................

Submitted by (print or type name and address)Telephone number:

Date:

Our Ref:

DSTAN Form 42N

(i)

INTERIM DEFENCE STANDARD 02603 (NES 603)

REQUIREMENTS FOR THE POLICY, DESIGN AND INSTALLATION

OF FIRE DETECTION SYSTEMS IN SHIPS

ISSUE 2

This Defence Standard is

authorized for use in MOD contracts

by the Defence Procurement Agency and

the Defence Logistics Organization

Published by:

Defence Procurement Agency,An Executive Agency of The Ministry of Defence,Directorate of Standardization,Kentigern House,65 Brown Street,Glasgow, G2 8EX.

DEF STAN 02603 / ISSUE 2(NES 603)

(ii)

INT DEF STAN 02603 / ISSUE 2(NES 603)

(iii)

SCOPE1. This Defence Standard is concerned with shipwide fire detection systems. The main fire

detection control panel and detectors shall form an Autonomous Fire Detection and AlarmSystem (AFDAS).

2. The basic general principles of this Defence Standard are to be applied to any fire detectionsystems that are fitted. Systems fitted to HM Surface Ships and Submarines are to complywith this standard, but boats and auxiliary vessels are excluded from the main requirements.

3. Autonomous fire detection systems comprise automatic fixed fire detectors, fire alarms,control panels, indicating units and the associated electric cabling to connect and energise thesystem. Their purpose is to protect the ship spaces and compartments.

4. Autonomous fire detection systems may be fitted to any class of vessel. When vessels have aPlatform Management System (PMS) or an integrated damage control and surveillancesystem, those elements peculiar to fire detection are to follow the principles of this standard.

5. Cabinet monitors, specific machinery monitors and automatic fire suppression systems withtheir own detectors (which employ techniques for fire detection similar to those of thisstandard) are the responsibility of the relevant equipment design authorities and are outsidethe scope of this standard. However, addressable fire detection systems are capable ofproviding identification of individual detectors and could display these alarms of fire at theFire Detection (FD) controller. Warship Project Manager (WPM) should be consulted on therequirement to display such alarms on the FD controller.

6. Portable fire detection or alarm systems for temporary protection during shipyard work, areoutside the scope of this standard.

7. Vessels procured for RN or RFA service but not normally described as warships, may be subjectto statutory rules and regulations. Guidance on the requirements for such vessels is providedwithin this standard, by reference to The Merchant Shipping (Fire Protection) Regulations1984 (and amendments) and to Lloyds Register of Shipping Classification Rules and Safetyof Life at Sea (SOLAS) Regulations.


(iv)


(v)

FOREWORD

Sponsorship

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

2. 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.

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

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

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

6. 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.

7. Extracts from British Standards quoted within this NES have been included with thepermission of the British Standards Institution.

8. This NES has been reissued to reflect changes in departmental nomenclature and the changesto technical requirements.

Conditions of Release

General

9. This NES has been devised solely for the use of the MOD, and its contractors in the executionof contracts for the MOD. To the extent permitted by law, the MOD hereby excludes all liabilitywhatsoever and howsoever arising (including but without limitation, liability resulting fromnegligence) for any loss or damage however caused when the NES is used for any otherpurpose.

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 MODit must 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 any 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, including Defence Procurement Agency,Naval Engineering Standards An Executive Agency of The Ministry of Defence,

Directorate of Standardization,Kentigern House,65 Brown Street,Glasgow, G2 8EX.

c. Other documents Tender or Contract Sponsor to advise.

17. All applications to Ministry Establishments for related documents are to quote the relevantMOD Invitation to Tender or Contract number and date, together with the sponsoringDirectorate and the Tender 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 inJSP430: MOD Ship Safety Management System Handbook.

Additional Information

(There is no relevant information included)


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CONTENTS

Page No

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

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

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

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

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

Categories of NES (vi). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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

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

Additional Information (vii). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CONTENTS (ix). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 1. POLICY STATEMENT 1.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.1 Fighting Ships and Submarines 1.1. . . . . . . . . . . . . . . . . . . . . . . 1.2 Commercial Standard Ships 1.1. . . . . . . . . . . . . . . . . . . . . . . . . . 1.3 Vessels Refitting 1.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 2. GENERAL REQUIREMENTS 2.1. . . . . . . . . . . . . . . . . . . . . . . . 2.1 Function 2.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2 Control 2.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3 Testing 2.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4 Autonomy 2.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5 Environment 2.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.6 Requirement 2.3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.7 Statutory Regulations (SI 1984/1218 and amendments) 2.3. . . .

SECTION 3. COMPARTMENTS AND SPACES 3.1. . . . . . . . . . . . . . . . . . . . 3.1 Requirements 3.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2 Explosive Risk 3.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.3 High Fire Risk 3.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.4 Ventilation Trunking 3.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.5 Statutory Regulations (SI 1984/1218 and SI 1981/1774

and amendments) 3.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 4. SYSTEM DESIGN 4.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.1 System Response 4.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2 Detectors 4.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3 Architecture 4.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.4 Redundancy 4.3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


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CONTENTS (continued) Page No

Table 4.1 Smoke Detectors 4.4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.5 Data Transmission 4.4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.6 Interface with Other Systems 4.4. . . . . . . . . . . . . . . . . . . . . . . . . 4.7 Statutory Regulations (SI 1984/1218 and amendments) 4.4. . . . Table 4.2 Maximum Spacing of Detectors

(SI 1984/1218 Schedule 11) 4.5. . . . . . . . . . . . . . . . . . . . . . . . . . .

SECTION 5. METHODS OF DETECTING FIRE 5.1. . . . . . . . . . . . . . . . . . . 5.1 Effects of Fire 5.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.2 Heat Detectors 5.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.3 Smoke Detectors 5.3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.4 Flame Detectors 5.4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.5 Performance of Heat Detectors 5.5. . . . . . . . . . . . . . . . . . . . . . . . Table 5.1 Heat Detector Temperature Ranges 5.6. . . . . . . . . . . . . . . . . . . . 5.6 Performance of Smoke Detectors 5.6. . . . . . . . . . . . . . . . . . . . . . 5.7 Performance of Flame Detectors 5.7. . . . . . . . . . . . . . . . . . . . . . . 5.8 Selection of Detectors 5.7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.9 Explosive and High Fire Risk Areas 5.8. . . . . . . . . . . . . . . . . . . . 5.10 Statutory Regulations (SI 1984/1218 and amendments) 5.8. . . .

SECTION 6. MOUNTING OF DETECTORS 6.1. . . . . . . . . . . . . . . . . . . . . . . 6.1 Mounting Base 6.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2 Position of Detectors 6.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Table 6.1 Recommended Limits for Deckhead Heights 6.1. . . . . . . . . . . . 6.3 Spacing 6.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Table 6.2 Recommended Coverage per Detector for

EDP Installations 6.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.4 Environment 6.3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.5 Statutory Regulations (SI 1984/1218 and amendments) 6.4. . . .

SECTION 7. CONTROLS AND INDICATORS 7.1. . . . . . . . . . . . . . . . . . . . . 7.1 Requirements 7.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.2 Response to Alarms 7.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.3 Manual Controls 7.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.4 Event Logging 7.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.5 Malfunctions 7.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.6 Indicators 7.3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.7 Location of Controls and Indicators 7.3. . . . . . . . . . . . . . . . . . . . 7.8 Statutory Regulations (SI 1984/1218 and amendments) 7.3. . . .

SECTION 8. ALARMS 8.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.1 Fire Alarm Sounder 8.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Table 8.1 Sound Attenuation up to 24 m 8.1. . . . . . . . . . . . . . . . . . . . . . . . 8.2 Fault Warning Sounder 8.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.3 Visual Indicators 8.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.4 High Intensity Beacons 8.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.5 Statutory Regulations (SI 1984/1218 and amendment) 8.3. . . .


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CONTENTS (continued) Page No

SECTION 9. SYSTEM INSTALLATION 9.1. . . . . . . . . . . . . . . . . . . . . . . . . . . 9.1 Selection of Cables 9.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Table 9.1 Conductor Sizes 9.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.2 Installation of Cables 9.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.3 Siting of System Components 9.2. . . . . . . . . . . . . . . . . . . . . . . . . 9.4 Mounting of Components 9.2. . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.5 Intrinsically Safe Circuits 9.3. . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.6 Precautions 9.3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.7 Statutory Regulations (SI 1984/1218 and amendments) 9.4. . . .

SECTION 10. POWER SUPPLIES 10.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.1 Fighting Ships and Submarines 10.1. . . . . . . . . . . . . . . . . . . . . . . 10.2 Commercial Standard Ships 10.1. . . . . . . . . . . . . . . . . . . . . . . . . . 10.3 Statutory Regulations (SOLAS Reg II-2) 10.2. . . . . . . . . . . . . . . .

SECTION 11. TESTS 11.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.1 Functional Tests 11.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.2 Electrical Tests 11.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.3 Statutory Regulations (SI 1984/1218 and amendments) 11.2. . . .

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

ANNEX B. ABBREVIATIONS, DEFINITIONS, SYMBOLS ANDUNITS B.1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Table B.1 Symbols and Units for Fire Detection B.6. . . . . . . . . . . . . . . . . . .

ANNEX C. PROCUREMENT CHECK LIST C.1. . . . . . . . . . . . . . . . . . . . . .

ANNEX D. FIRE AND SMOKE DETECTOR AND ALARMSYSTEMS FOR MERCHANT SHIPS D.1. . . . . . . . . . . . . . . . . .

Table D.1 Classification of Passenger Ships D.1. . . . . . . . . . . . . . . . . . . . . . Table D.2 Classification of Ships Other Than Passenger Ships D.2. . . . . . Table D.3 Fire Detection Regulations and Requirements for

Merchant Ships D.3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ANNEX E. SPACES AND COMPARTMENTS E.1. . . . . . . . . . . . . . . . . . . . Table E.1 Spaces and Compartments in RN and RFA Ships which

require Fire Detectors Prior to 1998 E.1. . . . . . . . . . . . . . . . . . . .

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


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INT DEF STAN 02603/Issue 2(NES 603)

1.1

1. POLICY STATEMENTRelated Documents: BR 862; BR 1754; NES 119; NES 501; NES 502; NES 1004;STANAG 1169; see also Annex A.

1.1 Fighting Ships and Submarines

a . The primary purpose of fitting fire detection systems is to maintain theoperational efficiency of fighting ships and submarines at all times. Thispurpose is achieved by providing early warning of the outbreak of fire to theDesignated Command or Monitoring Position (DCMP). This position willnormally be in the Ship Control Centre (SCC) unless otherwise stated in theship Statement of Technical Requirement (STR).

b . Fire detection systems shall cover all compartments/spaces and compartmentsas defined in NES 119.

c . Warning of the outbreak of fire, or Alarm of Fire, is to be confined to the DCMP,and to the locations specified in Section 8. of this NES. It is not to be broadcastautomatically throughout the vessel or be given in unspecified locations.

d . Fire detection systems, installed in fighting ships and submarines are not toinclude manual call points, unless specifically called for in the system STR.

e . Fire detection systems are to meet the relevant requirements of STANAG 1169,NES 119, BR 862 and BR 1754.

f . The design of every Fire Detection System is to meet the requirements of thisNES. Equipment designed specifically for MOD shall meet the generalrequirements of NES 501. Where Commercial off the Shelf (COTS) equipmentis to be used all items shall have been type approved and listed for marineapplication by an International Association of Classification Society (IACS)recognized classification society. All component equipments forming part ofthe fire detection system shall meet the requirements of NES 1004, asappropriate to the class of ship or submarine, and location within the vessel.Each installation is to be in accordance with NES 502.

1.2 Commercial Standard Ships

a . Some ships are procured to commercial standards for RN and RFA service. Firedetection systems fitted to such ships are to meet the requirements of theinternational convention for Safety of Life at Sea (SOLAS) published by theInternational Maritime Organization (IMO). The relevant British regulationsare The Merchant Shipping (Fire Protection) Regulations 1984 withamendments. Their purpose is to meet treaty obligations to safeguard the livesof passengers and crew.

b . Fire detection systems fitted to commercial standard ships for RN and RFAservice, are also to meet the requirements of an independent certificationorganization for classifying ships. Lloyd's Register of Shipping (LR) is such anorganization, and their requirements are published as Rules and Regulationsfor the Classification of Ships, Part 6. The purpose of these regulations is toensure that ships are constructed, maintained and operated to achieve a highstandard of safety for life and property.


1.2

c . Equivalent regulations are published by independent classification societiesbased in other NATO countries. These are:

American Bureau of Shipping (ABS) USA

Germanischer Lloyd (GL) Federal Republic of Germany

Registro Italiano (RINA) Italy

Fldenavis Spain

Bureau Veritas (BV) France.

Det Norske Veritas (DNV) Norway

d . Only IACS Classification Societies are to be used.

1.3 Vessels Refitting

a . RN ships and submarines which are undergoing repairs or refits in dockyards,may be subject to legal requirements to ensure the safety of a civilian workforce.The Health and Safety Executive has published Guidance Note GS 19 `Generalfire precautions aboard ships being fitted out or under repair'.

b . The fire detection systems of warships may provide less comprehensiveprotection than those of commercial standard ships. Additional fire risks maybe present as a consequence of dockyard operations. Therefore the installationof portable, temporary, fire detection systems, is to be considered in suchcircumstances.


2.1

2. GENERAL REQUIREMENTS

Related Documents: DEF STAN 59-41; NES 183; NES 1004; NES 1027; see alsoAnnex A.

2.1 Function

a . A fire detection system which complies with this NES is to monitor theenvironment within each selected compartment and space, so as to detect thesymptoms of fire within that environment. The environment is to becontinuously monitored at all times.

b . Whenever the symptoms of fire are detected, an alarm of fire is to be given,quickly and automatically, at the control station and elsewhere if required.

c . In any vessel, the fire detection system is to meet the vulnerabilityrequirements of the STR, so that an acceptable degree of protection ismaintained when an outbreak of fire, or other damage, occurs.

d . In any vessel, the fire detection system is to maintain cover during test andmaintenance operations to the system, or to any other part of the vessel and itsequipment.

e . Depending on the size and complexity of the vessel and its fire detection system,consideration is to be given to the need for automatic provision of a permanentrecord of the nature and time of all events occurring on the system.

2.2 Control

a . All components of the fire detection system in any vessel are to be controlledfrom a single control station, at any one time. The state of the system is to bevisually indicated at that station. The need for alternative control stations is tobe considered. Control is not to be shared between stations at any time.

b . Manual controls and indicators are to be provided in accordance with Section 7.of this NES, to allow for the resetting of the system after an outbreak of fire, orany other interruption. The controls are to permit disablement of anysubsystem.

2.3 Testing

a . The fire detection system is to monitor continuously the whole systeminstallation and its supplies, so as to detect automatically any fault,unambiguously distinguishing faults from symptoms of fire.

b . Whenever a fault is detected, an alarm is to be given, quickly and automaticallyat the control station, and elsewhere if required. The alarm of fault is to beclearly distinguishable from the alarm of fire. The nature and location of thefault are to be indicated at the control station.

c . Means are to be provided to test the system and its components, whilstcontinuing to monitor all selected compartments and spaces for symptoms offire. Restoration of the system after testing, without replacement of anycomponent, is to be possible.


2.2

d . Test facilities are to be provided to confirm the correct operation of the system.Correct operation includes the display of correct indications at the controlstation and elsewhere.

2.4 Autonomy

a . The fire detection system is to be functionally autonomous, as defined in theSCOPE. It is to be capable of functioning independently of all other systems.Interfaces, transmitting signals to other ship systems, may be provided, forexample, alarm signals.

b . Interfaces to receive signals from other ship systems, are not to be provided.

NOTE See Section 4.6 for vessels with a PMS or Integrated Damage ControlSystem (IDCS).

c . The ship fire detection system is for indication only. However, an outputconfirming the coincident alarm of two or more heat detectors in acompartment may be provided to a water spray control panel. Each heatdetector, on activation, would indicate an alarm of fire on the fire detectionpanel. The requirements for such spray systems would be specified in NES 183or the STR.

d . In vessels with integrated damage control and surveillance, the fire detectionsystem may be part or provide input into an integrated system. It may not thennecessarily function independently.

e . The power supply to the fire detection system is to be in accordance withSection10. An emergency power supply, with automatic changeover, is to beprovided.

2.5 Environment

a . The fire detection system is to perform correctly under the environmentalconditions specified in NES 1004. Reference is to be made to NES 1004 todetermine the requirements and testing for fire detection equipment, accordingto the class of vessel and location of the equipment.

b . Fire detectors are to be selected which detect the symptoms of fire without falsealarms caused by other environmental conditions such as ambienttemperature, salt laden atmosphere, shock, solar radiation, etc. Where theseconditions are unavoidable, detectors are to be installed so as to negate theeffects of the normal environment, and so permitting fire symptoms to bedistinguished.

c . Continuous monitoring to detect symptoms of fire is to be unaffected bydegradation or momentary interruption to the power supply to the fire detectorsystem, nor is it to be affected by the disruption of other circuits, or by theautomatic changeover to an emergency supply.

d . The electromagnetic compatibility characteristics of the fire detection systemare to be such that it does not degrade the performance of other equipment, andwill function properly in the environment of the vessel in which it is installed.Reference is to be made to DEF STAN 5941, and NES 1027 and STRs are tocontain a qualitative statement of the electromagnetic parameters which arenecessary and sufficient to meet the requirements of the environment asdefined by the Design Sponsor.


2.3

e . It is the Design Sponsor's responsibility to include in the STR only such tests asare essential for satisfactory operation, and to avoid unnecessary groups oftests.

2.6 Requirement

a . Autonomous fire detection systems installed in fighting ships, submarines andships for RN and RFA service built to commercial standards, are to meet therequirements of this NES.

b . Ships for RN and RFA service, but not normally described as warships, built tocommercial standards are also to meet the requirements of StatutoryInstrument 1984 No 1218 and amendments, and Lloyd's Rules and regulationsPart 6 and amendments. See Clause 1.2b .

c . For ships procured overseas from other NATO powers, acceptance of theclassification rules of an overseas society, a full member of IACS, equivalent tothose of Lloyd's Register, is to be considered.

2.7 Statutory Regulations (SI 1984/1218 and amendments)

a . The regulations in the Statutory Instruments require fixed fire detection andfire alarm systems, and fixed pressure water spraying systems to be installed.These installations are determined by the type of vessel (passenger, tanker etc),size of vessel, nature of cargo, numbers of passengers and the structural fireprotection methods employed.

b . Fire detectors are required in machinery spaces, and also in accommodation,service, cargo spaces and control stations. Manual call points are required inaccommodation spaces, in service spaces and galleys, companionways andescape routes and on the vehicle decks of car ferries. A fire patrol is required inpassenger ships.

c . A visible and audible alarm of fire is to be automatically initiated at the controlpanel and at indicating units. If these signals have not received attentionwithin two minutes, an audible alarm is automatically sounded throughout thecrew accommodation, and elsewhere.

d . Plans for the fire detection system are required to be submitted to theappropriate certifying authority, including details of the hardware and softwarefor programmable electronic systems.

e . The spacing of detectors, and floor area per detector, are specified. Detectorsare to be grouped in sections, with no more than 100 detectors per section, (referto Clause 4.2b).

f . The fire detection system may automatically initiate water spraying systemsand may close fire doors.

g . Components which have been commercially typeapproved are required to beused. Class societies such as Lloyd's Register publish lists of typeapprovedequipment which have been environmentally tested under Type ApprovalSchemes.

h . A permanent record of events occurring in the fire detection system is not amandatory requirement, but is recommended.


2.4

i . Annex D tabulates the statutory requirement for fire and smoke detectionsystems for merchant ships. For further information, reference is to be made toStatutory Instrument 1984 No 1218 and amendments, notably:

Schedule 7 Automatic Sprinkler, Fire Detection and Alarm Systems

Schedule 11 Fixed Fire Detection and Fire Alarm Systems and

Schedule 12 Sample Extraction Smoke Detection Systems.

j . The Statutory Regulations are based on the International Convention forSOLAS published by the International Maritime Organization. The relevantChapter is II2.


3.1

3. COMPARTMENTS AND SPACESRelated Documents: BR 862; BR 1754; BS 5345; DEF STAN 01-5; NES 102; NES 519;NES 626; NES 775; see also Annex A.

3.1 Requirements

a . For new vessels the Fire Detection System shall cover all Compartments/Spacesbut reference should be made to the ship STR which defines the completeinstallation requirements. The Fire Detection System alarms and warnings areto comply with NES 626.

b . For existing InService Vessels: As a minimum fire detectors are to be fitted in

Explosive Risk and High Fire Risk spaces and compartments.Ventilation trunking to and from such compartments.Electronic and Operational spaces of high value.

Reference is to be made to Annex E for definitions and examples of such spaces,and to the ruling documents tabulated in Annex E for further information.

c . Extensions of the minimum system to cover:

(1) Adjacent compartments to High Fire Risk Compartment (see Annex C);

(2) All unmanned spaces and compartments;

(3) All spaces and compartments;

to provide an enhanced level of protection should be considered wheneverpracticable.

3.2 Explosive Risk

a . Fire detectors are to be installed in all Magazines, Adjacent Compartments(except low fire risk compartments) and in Designated Danger Areas.Reference is to be made to NES 519 for definitions of these spaces, and toBR862, especially, for regulations concerning ship design and electrical safetyand for regulations concerning weapon stowage and adjacent compartments insubmarines.

b . Detectors installed in accordance with Clause 3.2a are to initiate alarms at thelocations specified in BR 862.

c . The term `gasoline' denotes all Petroleum Oils and Lubricants (POL) fuelswhich have been classified as `highly flammable' and are stored or used in HMShips. Reference is to be made to BR 1754 and NES 775 for definitions of`gasoline compartment' and `gasoline tank'.

d . BR 1754 Part 2, Article 0401 requires all gasoline compartments to be treatedsimilarly to magazines in respect of precautions against fire. Therefore firedetectors are to be installed in all gasoline compartments.

e . Detectors in the spaces covered by Clause 3.2a are to be installed in accordancewith NES 519. Detectors in the spaces covered by Clause 3.2d are to beinstalled in accordance with BR 1754.

3.3 High Fire Risk

a . Any compartment or space where material which is classified as `highlyflammable' or `flammable' is stored, handled or distributed is termed aDangerous Area. Reference is to be made to BR 1754 for detailed definitionswith examples. The materials present may include POL, LOX, paint, dope etc.


3.2

b . The classification of POL depends upon the flash point of the material.Reference is to be made to DEF STAN 015 for the flash point classification offuels, lubricants and associated products for MOD use.

c . Only detectors which have been certified for use in flammable atmospheres areto be installed in Dangerous Areas covered by Clause 3.3a . The CertifyingAuthority for Britishmade electrical equipment for use in Dangerous Areas isthe Electrical Equipment Certifying Service (EECS), a part of the Health andSafety Executive (HSE). There are equivalent overseas national authorities fornonBritish equipment.

d . The cabling, installation, and fittings for fire detectors and associatedequipment fitted in Dangerous Areas are to be in accordance with BR 1754Part 2, subject to compliance with the recommendations of BS 5345 Part 4.

3.4 Ventilation Trunking

a . Fire detectors are to be installed in the exhaust ducts of air conditioning andventilation systems which serve Explosive Risk, High Fire Risk and DangerousAreas. Such detectors are to be contained within probe units, which sample airflowing through the duct and detect combustion products originating in theprotected compartment or in the duct itself. Each probe unit is to be located sothat the normal airflow in the duct carries combustion products from thecompartment to the probe. The use of probes upstream, to give early warning ofthe products of combustion originating elsewhere, is to be considered.

b . Reference is to be made to BR 862 for information on the air conditioningsystems for Magazines, and to NES 102 for all other areas. Detector probe unitsare to be located so that the compartments and ducts are protected in the openship and closed down states, in all conditions of weather and climate and withthe possibility of false fire alarms minimized.

c . Fire detectors are not to be fitted in dedicated smoke clearance trunking.

3.5 Statutory Regulations (SI 1984/1218 and SI 1981/1774 and amendments)

a . Ships for RN and RFA Service built to commercial standards are to be fittedwith fire detectors, according to the ship classification under StatutoryInstrument 1984 No 1218 and amendments. Reference is to be made to AnnexB, and to Schedules 7, 11 and 12 of the regulations for the detailed requirementsand options. Reference is also to be made to BR 862 Part 4 to ascertain theapplicability of Naval Magazine and Explosive Regulations to MOD ships andcraft not manned by the RN, and especially the regulations for fire detectionand alarm systems.

b . The installation is to meet the requirement of Clause 3.1b , and in addition firedetectors are to be installed to protect the following spaces:

(1) Accommodation spaces including corridors, escape routes, lobbies andstairways;

(2) Cargo spaces, including closed and open ro/ro spaces;

(3) Control stations;

(4) Public spaces;

(5) Spaces not reasonably accessible to the fire patrol;

(6) Special category spaces, if not patrolled or if carrying dangerous goods.


3.3

c . The Statutory Instrument permits the installation of sample extraction smokedetectors to protect the following spaces:

(1) Spaces not reasonably accessible to the fire patrol;

(2) Cargo spaces containing motor vehicles with fuel in their tanks for theirown propulsion (other than special category spaces or ro/ro spaces);

(3) All other cargo spaces including those for dangerous goods;

d . It should be noted that the use of such sample detectors is not preferred, and thespecific permission of the MOD is to be obtained before they are installed in anyMOD vessels.

e . For details of the classification, marking, notification and regulations for thecarriage of dangerous goods in merchant ships, reference is to be made toStatutory Instrument 1981 No 1747 (and amendments) and to the relevantdocuments listed therein.


3.4


4.1

4. SYSTEM DESIGNRelated Documents: BS 5839 Part 1; BS 6387; BS EN 54 Parts 1, 5, 7, 8 and 9;NES 502; NES 620; see also Annex A.

4.1 System Response

a . The system is to initiate an alarm of fire when symptoms of fire are present inany protected compartment or space. It is essential that the time delay betweenthe outbreak of fire and the alarm signal is minimized. Therefore a rapidresponse is more important than a response which depends on level ofobscuration by smoke, or on rise of temperature.

b . An oversensitive system will cause false fire signals due to accident ormalfunction. An acceptable compromise to achieve a rapid response without anexcessive number of false signals is to be sought.

c . Advice is to be sought from potential system suppliers as to the response timeand incidence of false fire signals claimed for their products. STRs are to drawattention to the uncertainties which affect statements about the normalenvironment for a fire detector on board ship, for example, the effects ofweather and ventilation currents when at sea. The needs for additionaldetectors for protection when not at sea are to be considered.

d . The response of a fire detection system is specific to the class of vessel, and to thespace which it is protecting. It is therefore impracticable to enumerate limitsfor response time or for false fire signals, either in this NES or in STRs. Note:For fire detection on land, BS 5839 Part 1 states that the average rate of falsealarms from an installation should not exceed one false alarm per year for each10 detectors fitted to the system. The number of false alarms from an individualdetector or detector location should not exceed one false alarm per two years.

e . Detector circuits are to be arranged so that a fault warning is given within 100 sof the occurrence, of any open or short circuit in a cable which would disable oneor more detectors (and/or call points if fitted), or of a failure of any otherinterconnection.

f . Response times required during system acceptance trials on board are to bebased on response times claimed by the system supplier.

4.2 Detectors

a . Fire detectors installed in surface ships and submarines are to be of typesapproved by the MOD. They are to be selected from types which have beentypeapproved and listed for marine applications by a recognized classificationsociety. The need for additional type testing to confirm their suitability for thewarship environment is to be considered.

b . Detectors are to be mounted in all the compartments, spaces and trunks whichare to be protected. The spacing and mounting of detectors are determined bythe geometry of the compartment and by regulations, and are to comply withthe requirements of Section 6.

c . The nature of the fire risk which is anticipated at each location is to beconsidered when selecting the types of detector required (Clauses 5.1a to 5.1frefer).


4.2

d . Detectors are to comply with the relevant parts of BS EN 54 Parts 5, 7 or 8 whichprovide for three classes of fire sensitivity. Reference is to be made to BS EN 54Part 9, and detectors are to be selected with response values suitable for theanticipated type of fire, so as to provide a quick alarm signal and a low level offalse fire signals. In locations where contamination of the detector is likely tooccur, the use of detectors which give a prealarm warning of output signal drift,is to be considered.

e . In locations where the environment makes unambiguous detection of firesymptoms difficult, the use of coincident and varied design of detectors andsuitable control circuitry, is to be considered. For machinery spaces a variety ofsmoke detectors, i.e. Ionisation Smoke Detectors and Photoelectric SmokeDetectors, may be considered to provide the optimum protection whilstminimising the risk of spurious alarms.

f . BS EN 54 Part 1 applies to components of automatic fire detection systems forbuildings. It may also be used as a basis for the assessment of components ofsystems for other purposes, e.g. mines, ships. BS EN 54 is not to be confusedwith other British Standards which apply to components of automatic firedetection systems for use in residential premises. Compliance of an individualcomponent, such as a fire detector, with a part of any published BritishStandard does not necessarily guarantee that it will work satisfactorily inconjunction with another component similarly complying. Reference is to bemade to BS 5839 Part 1 for advice on compatibility, and STRs are to provideadequate information to ensure compatibility, especially if components are tobe procured from more than one manufacturer. Clause 5.8a refers.

4.3 Architecture

a . Detectors are to be connected in such a manner that the location of fire can bequickly identified at the control station. This may be achieved by subdividingthe whole installation into sections, by the installation of an addressablesystem, or by some combination of such arrangements. Faults which occur inany section are not to prevent the correct operation of other sections.

b . Subdivisions of the system are to be termed `sections'. The term `zone' is to beconfined to structural divisions of the vessel. A zone may contain a number offire alarm sections.

c . Removal of any detector from its section circuit is not to prevent operation ofother detectors in that circuit, or of any fire alarm sounder which is connectedin a common circuit.

d . The numbers of sections, and the size of each section, in any vessel are to bedetermined by consideration of the following factors:

(1) The distance/area which must be searched from the point of entry beforethe site of the fire is visually located. Where a section contains closedcompartment doors, visible external indicators reduce the searchdistance.

(2) Section boundaries are to coincide with compartment and spaceboundaries such as bulkheads. Several compartments may be protectedby one section.

(3) Statutory regulations contain specific requirements. Clause 4.7d refers.

(4) Detector current and power requirements.


4.3

e . Controls, indicators and sounders are to be provided and located as required bySections 7. and 8. of this NES. The need for duplicate alarms (Clause 7.7d refers) is to be considered.

f . The architecture is to be such that at least one sounder will be capable ofoperating following an outbreak of fire. The provision of high integrity cable forsounders is to be considered and reference is to be made to BS 6387 for furtherinformation, and Clause 9.1 of this NES.

g . The design of a new system should ensure that the loading of the system doesnot exceed 75% of maximum capacity to allow for future expansion. Forwarships and vessels in which a fire detection system of more than 50 detectorsis employed, an addressable fire detection system shall be fitted.

h . Addressable intelligent systems provide facilities which are difficult orimpossible to achieve with conventional systems. For example:

(1) The source of a fire signal can be traced to an individual detector;

(2) Alarms may be confirmed by addressing adjacent detectors e.g. coincidentdetectors in magazines;

(3) Fire signals can be compared against stored values before triggering analarm;

(4) Genuine fire signals can be distinguished from slow drift due tocontamination or ageing of the detector sensor;

(5) The threshold signal limit for each detector can be adjusted to allow forlocal environmental conditions;

(6) The order and frequency of interrogation of detectors can be adjusted tomatch the fire risk;

(7) Detectors can be tested remotely;

(8) Detector performance can be monitored for timely replacement.

i . Detectors in addressable systems may be connected in a number of continuoustwowire loops, or double that number of single lines. Some systems permit theconnection of spurs of conventional detectors. Modular extensions are possible,using a serial communication data bus, for very large installations.

j . The control and indicating equipment for addressable systems is to comply withBS 5839 Part 4 pending the publication of the equivalent European Standard.The need for additional environmental testing appropriate to the class of vesseland location of the control station, is to be considered.

k . For systems which incorporate software, NES 620 is to be consulted.

l . System architecture is to be such that the lengths of cable and number ofpenetrations of watertight bulkheads and decks are kept to a minimum. Cableroutes are to be in accordance with NES 502.

4.4 Redundancy

a . Preference is to be given to system configurations that allow redundantcommunication paths between components. Such redundancy is to maintainprotection against fire when the system is itself damaged, by fire or othercauses.


4.4

b . At least one detector is to be installed in every protected compartment. Visualindicators are to be provided outside normally locked compartments (Clause4.3d refers), and outside compartments where a section protects more than onecompartment.

c . The maximum spacing of detectors, and floor area covered per detector are notto exceed the statutory limits (clause 4.7d Table 4.2 refers). For the protectionof magazines the number of smoke detectors shall be as specified in NES 183.The numbers of smoke detectors fitted in Flammable and Paint Stores andother High Risk areas shall be as specified for magazines in NES 183 which iscurrently as follows:


4.5

Type ofdetector

Maximumfloor area per

detector

Maximumdistance apart

between centres

Maximumdistance away

from bulkheads

Heat 37 m2 9 m 4.5 m

Smoke 74 m2 11 m 5.5 m

Table 4.2 Maximum Spacing of Detectors (SI 1984/1218 Schedule 11)

Other spacings based upon test data which demonstrate the characteristics ofthe detectors may be required or permitted.

e . Sections are not permitted to protect spaces on more than one deck (except forenclosed stairways). No section is to protect more than 50 compartments. Nosection is to contain more than 100 detectors. Sections are not to protect spaceson both sides of a passenger ship, or in more than one vertical zone, withoutspecial permission. Machinery spaces are not to be included in sections whichprotect a control station, service, accommodation or cargo space.

f . Reference is to be made to 1984 Statutory Instrument No 1218 Schedules 11and 12 for further details.

g . Reference is to be made to Lloyd's Rules for Classification of Ships Part 6 andamendments, for regulations concerning:

(1) Type approval of programmable electronic equipment;

(2) Local Area Network (LAN) for transfer of alarm data between computersand data gathering equipment;

(3) Software for programmable electronic systems;

(4) Integrated computer systems;

(5) Additional fire protection;

(6) Periodically unattended machinery spaces.


4.6


5.1

5. METHODS OF DETECTING FIRE

Related Documents: BR 1754 Part 2; BS 5345 Part 4; BS 5446 Part 1;BS 5501 Part 7; BS EN 2; BS EN 54 Part 5, 7, 8 and 9; BS EN60529; JSP 392; NES 1004;see also Annex A.

5.1 Effects of Fire

a . Fire is the process of combustion, in which substances join chemically withoxygen and emit heat, accompanied by smoke and/or flame. Heat, smoke andflame are the characteristic properties of fire. In order to detect a fire, one ormore of these properties must be distinguished from the backgroundenvironment. In an automatic fire detection system, the fire detectors monitorthe atmospheric environment of the area to be protected, either continuously orat frequent intervals. Sensors within the detectors respond to the presence ofheat, smoke or flame and generate a signal suitable for measurement.

b . The three requirements for fire are heat, oxygen and fuel. When these arepresent in the correct proportions, fire will result. Fires are classified inBSEN2 according to the fuels involved (fire classification, Para B4. refers).However, ignition, (initiation of flaming combustion) occurs only in the gas orvapour phase. Thermal energy must be supplied to solids and liquids to convertpart of the fuel into vapour. The lowest temperature at which ignition occurswithout the application of a flame is the autoignition temperature of the fuel.

c . The ease of ignition of solid materials (Class A fires) depends largely on surfacearea. In bulk form, fire growth is relatively slow and progressive. In the earlysmouldering stages smoke is given off. A smoke detector will detect such a fireearlier than a heat or flame detector.

d . Liquids (Class B fires) give off vapours. The lowest temperature at whichenough vapour is given off to ignite momentarily when a flame is applied iscalled the Flash Point. A few degrees above the flash point is the Fire Point.This is the lowest temperature at which liquid in an open container will sustainburning after ignition. The size of a Class B fire depends on the area of liquidexposed. A flame detector can respond more quickly to a Class B fire than asmoke or heat detector, especially in an unconfined space.

e . The ignition of gases (Class C fires) and vapours is rapid and may be explosive.Propagation of a flame will occur if the concentration of vapourtoair isbetween the lower and upper flammable limits. Cleanburning fires may bedetected by heat or flame detectors. Smoke detectors are unlikely to give earlywarning, unless smoke is produced by other combustible materials which maybe present.

f . Most metals will burn in air (Class D fires) under the correct conditions.Certain metals, e.g. magnesium, titanium, zinc, calcium etc are termedcombustible, because thin sections and fine particles can be ignited easily. Heator smoke detectors will detect Class D fires.

g . The nature of the likely fuel is an important factor when selecting a firedetector. Other factors which are to be taken into account are described in thefollowing paragraphs.


5.2

5.2 Heat Detectors

a . Heat detectors respond to the temperature of gases in their vicinity. The hottestgases generally rise by convection to the highest point of a compartment, andheat detectors are therefore fitted to the deck head. The size of fire to which aheat detector will respond increases markedly with the height of the mounting.Heat detectors require the flames to reach about onethird of the way to thedeckhead before operating. Heat detectors could detect a fire that evolvesquickly with very little smoke, e.g. a flammable liquid, more rapidly than smokedetectors. Heat detectors do not respond to smouldering fires. They areunsuitable for detecting small fires which could cause unacceptable losses.They are not suitable for external spaces.

b . Point heat detectors protect a small area around and below the detector. Theyare available in Response Grades 1, 2 and 3 of which Grade 1 is the mostsensitive. They contain a fixed temperature sensor, designed to operate when itreaches a preselected threshold temperature. They may also be capable ofdetecting an abnormal rateofrise of temperature, either by use of a separatesensor, or (as in analogue sensors) by electrically modifying the output of asingle sensor to produce the desired response.

c . The sensors used in point type heat detectors are thermistors, bimetals orthermocouples. A typical modern thermistor detector consumes 70 A in thequiescent state.

d . Heat detectors with rateofrise elements are most effective where the ambienttemperature is low, or varies only slowly. Fixed temperature detectors are moresuitable where the ambient temperature is likely to fluctuate rapidly over shortperiods. Where the ambient temperature is likely to exceed 43C, as in galleysand machinery spaces, any heat detectors are to be high temperature versions.The nominal operating temperature of a heat detector is not to exceed theexpected maximum ambient temperature by more than 30C. Fixedtemperature heat detectors are not suitable for cold stores where thetemperature is abnormally low.

e . Point heat detectors are to comply with BS EN 54 Part 5 for use below 43C, andPart 8 for use at high ambient temperatures.

f . Line heat detectors protect larger areas by responding to heated gases along anypart of the detector line, which need not be straight. The response of anintegrating line detector at any one point is modified by the temperature of theremainder of the line. In nonintegrating detectors response is at one point only.

g . Fire alarm cable consists of two metal cores held apart by a heat sensitivecovering and sheathed for mechanical protection. When the temperature risesto the melting point of the covering, at any part of the cable, the cores makeelectrical contact and signal an alarm. Machinery and cable ducts can beprotected by monitoring the resistance of a special type of cable, using a bridgecircuit. High temperatures unbalance the bridge and raise an alarm.

h . A fibreoptic distributed temperature sensing system is commercially availablefor line heat detection in power cables, for machinery monitoring and firedetection. The temperature profile of a 2 km cable loop may be determined to aclaimed accuracy of 1C in a time of 12 seconds, and a hot spot may be locatedwithin a few metres. The system employs the technique of time domainreflectometry.


5.3

5.3 Smoke Detectors

a . Smoke detectors respond to particles of smoke. These are solid and/or liquidand range in size from 1 nm to 10 m. The smallest particles, produced byrapidly burning flaming fires, are invisible to the naked eye. Cleanburningliquids, e.g. alcohol, do not produce smoke particles, but other combustiblematerials are likely to be present at such fires. Smoke detectors are not suitablefor external spaces, or for spaces where smoke, dust or fumes are normallypresent. In general, smoke detectors respond more rapidly than heat detectors,but are more liable to give false fire signals.

b . There are two types of smoke detector, point type ionization chamber smokedetectors and point type optical (photoelectric) smoke detectors. Both pointtype ionization smoke detectors and optical point type detectors using scatteredand/or transmitted light are to conform to BS EN 54 Part 7.

c . Point type ionization smoke detectors are particularly sensitive to smallparticles, but relatively insensitive to large particles, such as coalesced tobaccosmoke, or smoke from overheated PVC or smouldering polyurethane foam.False or spurious fire alarms may be caused by diesel exhaust, self cleaningovens, high humidity and high air speeds.

d . The ionization chamber is the sensing element in this type of smoke detector.The air in the chamber is made conductive, or ionized, by bombardment withalpha particles emitted from a minute radioactive source. The chambercontains two electrodes across which a voltage is applied, and a very smallcurrent flows as the +ve and -ve ions travel to the electrode of oppositepolarity. When smoke particles enter the chamber they attach themselves tothe ions, cause a reduction in mobility and reduce the current flow. Thereduction in current is a measure of the number and size of smoke particlespresent. Modern detectors contain two chambers, one open to the smoke, theother a semisealed reference chamber. The imbalance between the chambers isamplified and causes a large change in signal current, typically from 25 A to55mA.

e . Pointtype optical smoke detectors respond to the scattering of light, caused byparticles of smoke. Typically they are sensitive to particles 0.5 m to 10 mminimum size such as are emitted from a smouldering fire or by burningplastics, as in overheated wiring. False fire signals may be caused by coalescedparticles of tobacco smoke. Optical detectors are designed to reduce falsesignals caused by variations in ambient light, by the intrusion of minute insectsand by dust contamination.

f . The light source for an optical smoke detector is usually an infra-red LightEmitting Diode (LED) which is pulsed at intervals of typically 2 seconds to10 seconds. Smoke entering the chamber containing the LED, causes the lightto be scattered on to a photocell or photodiode. The output of the latter iscompared with a preset value representing the `no smoke' condition. When asuccession of consecutive pulses confirms the presence of smoke, a fire signal isgiven. In some designs, the pulse rate can be accelerated at the first indicationof smoke, to avoid delay. Typically the fire signal is given when the obscurationreaches about 3% per metre.


5.4

g . Optical smoke detection systems are used on merchant ships to protect anumber of spaces, by sampling air extracted from each space and passed to acentral smoke detector cabinet. A typical system can sample air from up to 18input ports, via a 20 mm bore pipework. The source of each sample can bevisually identified. Such systems conform to Schedule 12 of StatutoryInstrument 1984 No 1218 which requires them to give a fire signal before thesmoke density in the chamber exceeds 6.65% obscuration. Sample extractionsmoke detectors are not to be used in ships for RN and RFA service. Clause 3.5c refers.

h . Optical beam smoke detectors are used to protect large areas. A pulsed lightsource is focussed to produce a beam which is detected by a photocell.

i . Development of the photoelectric optical point type smoke detector hasresulted in this type of detector being considered as providing an acceptablecompromise between sensitivity and resistance to spurious activity. They arerecommended for general purpose fire detection. These detectors do not pick upthe `invisible' smoke produced by rapidly burning fires such as flash firescaused by vaporised fuels igniting, therefore, within machinery spaces aselection of ionization and optical detectors are to be fitted to give the optimumlevel of protection.

j . Photoelectric optical point type smoke detectors may be fitted to a probe unitto detect smoke in the ducts of air conditioning and ventilation systems. Thesampling tube of the probe unit has one end sealed and a row of equally spacedholes along its length. This tube, with its holes facing into the air stream,introduces air together with any combustion products into the expansionchamber. Inside the expansion chamber the air is slowed down as it passes thedetector head. This enables effective sampling to take place. The detectorprotects the ducting and spaces upstream from the detector. Clean air suppliedthrough the duct, close to the sample point, will reduce the intensity of smokereaching the detector. Protection is lost as the air supply is interrupted orreversed. Malfunction may occur in turbulent flow, high speed flow, or variableair speeds. False fire signals may be given if the duct is used for smokeclearance.

5.4 Flame Detectors

a . Flame detectors respond practically instantaneously to the radiation emittedby flame, and are mounted to protect the area within a direct line of sight. Theviewing field is 70 to 120 inclusive angle. It may be extended using an array ofdetectors, or by a rotating mirror to scan a full 360 in azimuth. The sensor of aflame detector is a photocell sensitive to the wavelength of radiated energy.

b . Flame detectors cannot detect smouldering fires and are not suitable forgeneral purpose applications. They are used to supplement smoke or heatdetectors. For speedy detection, a clear line of sight to the protected area isnecessary. A flame detector will respond to flames reflected from parts of astructure, but a significantly bigger fire will then be needed before a fire signalis given. Flame detectors can respond to a flaming fire, such as a Class B liquidfire (e.g. gasoline) more rapidly than smoke or heat detectors. They need not bemounted at the deckhead where smoke and hot air accumulate. They aresuitable for use in tall vertical spaces, machinery spaces, in outdoor spaces, andwhere a flaming fire may spread quickly such as at pumps, valves and pipework.


5.5

c . Infrared flame detectors respond to a combination of the infrared radiantenergy and the flame flicker characteristic of most types of flame. Detectors aredesigned to respond to radiation flicker frequency, and to specific wavelengths,in order to discriminate fires from other sources such as sunlight. False firesignals may be caused by poorly adjusted gas/oxygen flames. An integratingcircuit is provided so that no fire signal is given if radiation does not persist.Scanning detectors may be programmed to pause for a few seconds when apossible fire signal is detected. False signals may also be caused by reflectionfrom shimmering puddles, by a hot incandescent body within range, or by theinterruptions of a steady source by blades of a fan. The detector may not sense ahigh pressure gas fire which does not flicker. Its performance will be degraded ifthe viewing aperture is obscured in any way.

d . Ultraviolet flame detectors respond to ultraviolet radiation, normally in thewavelengths from 200 nm to 270 nm. They are not actuated by sunlight becausesolar radiation in this range is normally absorbed by the high altitude ozonelayer. False fire signals may be caused by ultraviolet lamps, by cutting andwelding operations, or by lightning. Ordinary window glass, and certainabsorbent gases, will screen ultra violet radiation. Ultraviolet flame detectorscan detect electric sparks, static discharge and corona discharge.

e . The level of radiation received by a flame detector is inversely proportional tothe square of the distance from the flame. Consequently, a larger fire is neededto trigger a response at a greater distance. A typical infrared flame detector,with a field of view of 100solid angle, will respond to a 0.1 m2 flaming firewithin a cone 12 m high, 13 m base radius. At 24 m height, 26 m base radius, thefire has to reach 0.4 m2 before response.

f . Infrared radiation penetrates smoke well, but ultraviolet radiation may berapidly absorbed by smoke and by some hazardous vapours. If the outbreak offlame is likely to be preceded by smouldering, an infrared detector will give thequicker response. Dualspectrum detectors combine ultraviolet and infraredsensors, arranged to resemble binoculars. Their control logic is designed torespond to different types of flame and to reduce the incidence of false firesignals. A typical dualspectrum detector may respond in about 1 second to firein a 30 cm square pan as follows:

(1) Diesel fuel, at a range of 9 m;

(2) Gasoline, at a range of 13.7 m.

g . There is no British Standard for flame detectors as part of a fire detectionsystem. Flame detectors are only to be used when backed up by smoke or heatdetectors. Manufacturers' advice is to be sought before selecting infrared,ultraviolet or combination flame detectors for a given location.

5.5 Performance of Heat Detectors

a . Manufacturers of point heat detectors claiming conformance to BS EN 54 Parts5 and 8 are required to satisfy themselves that any such detector is capable ofpassing all the tests and of meeting all the requirements of the relevant Part.Reference is to be made to the appropriate Part of BS EN 54 to ascertain:

(1) The methods by which the time of response is measured and theacceptance limits for the various types and grades of detector;

(2) The nature and severity of the environmental tests which detectorsconforming to BS EN 54 are required to withstand.


5.6

b . The environmental tests of BS EN 54 Parts 5 and 8 are to be compared with therequirements of NES 1004 relevant to the system STR.

c . Point heat detectors conforming to BS EN 54 Part 5 are marked to show theirresponse grade, usually by colour coding as follows:

Response grade 1: green (most sensitive);

Response grade 2: yellow;

Response grade 3: red (least sensitive).

d . Point heat detectors conforming to BS EN 54 Part 8 are marked to show themaximum ambient temperature for which they are suitable. There are fourranges as follows:

Normal ambient temperature Temperature range

up to 70C 1

up to 90C 2

up to 110C 3

up to 140C 4

Table 5.1 Heat Detector Temperature Ranges

5.6 Performance of Smoke Detectors

a . Manufacturers of point type smoke detectors using scattered light, transmittedlight, or ionization and claiming conformance to BS EN 54 Part 7, are requiredto satisfy themselves that any such detector is capable of passing all the testsand meeting all the requirements of that Part. Reference is to be made toBSEN54 Parts 7 and 9 to ascertain:

(1) The methods by which the response threshold values are measured andthe acceptance limits for the various types of detectors;

(2) The methods by which Fire Sensitivity Tests are conducted and thelimiting values of the alarm points for classification as Class A, B or C;

(3) The nature and severity of the environmental tests which detectorsconforming to BS EN 54 are required to withstand.

b . The environmental tests of BS EN 54 Part 7 are to be compared with therequirements of NES 1004 relevant to the system STR.

c . Smoke detectors conforming to BS EN 54 Part 7 are required to detect test firesand to be classifiable under Class A, B or C as suitable for detecting particulartypes of fire. The BS does not require the detectors to be marked with a Classletter. BS EN 54 Part 9 contains details of the test fires and procedure forclassification.


5.7

d . The fire sensitivity of point type smoke detectors, (irrespective of operatingprinciple) which are intended for the protection of life in compartments wherepeople sleep, is tested by a similar, but not identical, procedure. For slow andfast burning wood fires, a response not later than 10 seconds after the smokedensity has reached 0.5 dB/m is required. For liquid hydrocarbon, andpolyurethane foam fires, the response is to be not later than 10 seconds after adensity of 0.8 dB/m. BS 5446 Part 1 provides further information.

5.7 Performance of Flame Detectors

a . Reference is to be made to manufacturers' literature to ascertain the firesensitivity of flame detectors, and to compare claimed performance underenvironmental stress with the requirements of NES 1004.

b . Flame detectors are available which have been type approved by Class Societiessuch as Lloyd's Register. They are capable of withstanding operatingtemperatures ranging from -20C to +70C (in addition to the otherrequirements of the Type Approval Scheme) at up to 95% Relative Humidity(RH). For use on open decks, enclosures providing protection to at least IngressProtection (IP) 56 are required. BSEN60529 specifies the degrees ofprotection provided by enclosures. Open deck flame detectors are also requiredto withstand the Lloyd's Register Salt Mist Test.

5.8 Selection of Detectors

a . Detectors from different manufacturers are not necessarily mechanically orelectrically interchangeable, even though they comply with British Standards.Therefore, whenever possible, the use of detectors from more than onemanufacturer is to be avoided in fire detection systems for RN and RFA shipsand submarines.

b . Fire detectors are to be selected which will respond rapidly to the type of fireswhich are anticipated in the spaces to be protected, without giving rise tofrequent false fire signals. The size, shape and environment of the space is to betaken into account. For general purpose fire detection, the photoelectricsmoke detector is recommended, because it represents an acceptablecompromise between sensitivity and spurious activity.

c . When ionization chamber smoke detectors are specified, reference is to be madeto JSP 392. It is the responsibility of the Design Sponsor to ensure thatapproval has been obtained for the installation of fire detection systems thatinclude any source of ionizing radiation, in accordance with the procedures ofJSP 392. The level of radioactivity of the source contained in any fire detector isnot to exceed 33 kBq (equivalent to 0.89 Ci).

d . All ionization chamber smoke detectors are to be marked with a radiationtrefoil, or the word `Radioactive' and details of the radionuclide and the activitythat they contain. The trefoil symbol is to be in accordance with JSP 392.

e . Ionization chamber smoke detectors are to incorporate shields and means forpreventing access to the ionizing source in accordance with Section 5. of theApproved Code of Practice, issued by the Health and Safety Commission andincluded in JSP 392.

f . All detectors are to withstand the environmental stresses to which they will besubject in their respective locations.


5.8

g . The operating voltage, quiescent current, alarm current, modulating voltageand all other electrical parameters of all detectors are to be compatible with thefire detection system into which they are installed. Clause 4.2f refers.

5.9 Explosive and High Fire Risk Areas

a . Fire detectors and their mounting bases installed in Explosive Risk Areas, andin High Fire Risk Areas that are designated as Dangerous Areas, (as inClause3.3a and Annex E), are to be certified as intrinsically safe in accordancewith an appropriate standard e.g. BS 5501 Part 7. They are to be installed inaccordance with BS 5345 Part 4, category to suit the (hazardous area) zone ofuse.

b . The cabling, installation, and fittings for fire detectors installed in areascovered by Clause 5.9a are to be in accordance with BR 1754 Part 2, subject tocompliance with the recommendations of BS 5345 Part 4. Any necessary safetybarriers for power supply are also to be certified and approved.

c . The Certifying Authority for Britishmade electrical equipment for use inExplosive and High Fire Risk Areas that are designated as Dangerous Areas, isthe Electrical Equipment Certifying Service (EECS), part of the Health andSafety Executive. There are equivalent overseas authorities for nonBritishequipment.


a . All detectors are to be such that normal surveillance can be restored aftertesting without renewal of any component.

b . Smoke detectors in accommodation stairways, corridors and escape routes areto be certified to operate before the smoke density exceeds 12.5% obscurationper metre, but not to operate until the smoke density exceeds 2% obscurationper metre. Sensitivity limits elsewhere are to avoid oversensitivity andinsensitivity.

c . The sensing unit of sample extraction smoke detection systems is to be certifiedto operate before the smoke density in the sensing chamber exceeds 6.65%obscuration per metre.

d . Heat detectors are to be certified to operate before the temperature exceeds78C, but not until it exceeds 54C, when it is raised at a rate of less than1C/minute.

e . Heat detectors in drying rooms, and similar spaces where the ambienttemperature is normally high, are permitted an operating temperature 30Cabove the maximum deckhead temperature.

f . Manual call points will not normally be fitted. Where the STR defines themthey are to comply with the Regulations.

g . In machinery spaces, systems using only thermal detectors are not permittedexcept where height is restricted, or where thermal systems are speciallyappropriate.

h . Fire detection and alarm systems are to be of an approved type. Fire detectorheads are to be Type Approved in accordance with Lloyd's Register TypeApproval Schemes.

i . When fire detectors are provided with means to adjust their sensitivity, thearrangements are to be such that the set point can be fixed, readily identified,and recorded.


6.1

6. MOUNTING OF DETECTORSRelated Documents: BS 5839; BS 6266; BS EN 54 Part 7 and 8; DEF STAN 5941;NES 1004; see also Annex A.

6.1 Mounting Base

a . A mounting base is to be fitted at each position selected for a fire detector. Thebase is to allow for rapid insertion and removal of the detector. Section circuitcontinuity is to be maintained in the absence of the detector.

b . Bases are to accept detectors of all the types, grades and sensitivities used in thefire detection system of which they are a part. Means to prevent insertion of thewrong type of detector into a mounting base are to be incorporated. Bases foruse in areas covered by Clause 5.9a are to be certified as intrinsically safe.

c . Each base is to have a space for permanently marking the address of its detector,see Clause 4.3.

d . For addressable systems the means to define the address of a detector positionshall be incorporated within the fixed base at each detector and not within anypart that may be removed for routine maintenance.

6.2 Position of Detectors

a . Detectors are to be positioned for optimum speed of detection whilstminimizing the possibilities for false fire signals. The sensitivity of the detector,and the orientation appropriate to each position, are to be considered.

b . Smoke and heat detectors, which sense the products of combustion are to bepositioned so that these products reach them quickly. The optimum positionwill normally be at the deckhead, taking account also of the movement of airand of the ventilation systems. Where practicable, a spacing of not less than 1 mbetween a detector and an air inlet should be maintained. An exploratorysmoke test can aid the identification of optimum locations. The use of airdeflectors and shields is to be considered in constricted locations.

c . BS 5839 Part 1 Table 1 and BS 6266 include recommendations for thepositioning of fire detectors in buildings and in electronic data processinginstallations, some of which are relevant to marine fire protection systems. Thedeckhead height for pointtype smoke and heat detectors is not to exceed thelimits of Table 6.1. If the delay before fire fighting starts is no more than fiveminutes, increases of about 50% in deckhead height are permitted in theStandard.

Detector Type Deckhead height m

Heat detectors Grade 1 9.0

Grade 2 7.5

Grade 3 6.0

High temperature heat detectors (BS EN 54 Part 8) 6.0

Point smoke detectors 10.5

Table 6.1 Recommended Limits for Deckhead Heights


6.2

Heat sensitive line detectors are to be mounted as close as possible to the placewhere fire or overheating might occur, either above the risk or in thermalcontact with it. In open areas, under flat horizontal deckheads, the horizontaldistance from any point in the area to its nearest detector is not to exceed 5.3 mfor heat detectors, or 7.5 m for smoke detectors. The vertical distance betweensensor and deckhead is to be 25 mm to 150 mm for heat detectors, and 25 mm to600 mm for smoke detectors.

d . Flame detectors are to be positioned so that there is a direct line of sightbetween detector (or reflector if of the scanning type) and all points in theprotected area. Detection is not to depend on reflection from a part of thevessel's structure. The need for screening from solar or other radiation whichmay be normally present, is to be considered, and positions where reflectionscould cause false fire signals are to be avoided.

e . Detectors are to be positioned so that there is ready access for testing and forreplacement.

6.3 Spacing

a . At least one detector is to be installed in every protected compartment. In anyprotected compartment, the maximum floor area per detector fitted is to be notmore than 74 m2 for smoke detectors, or 37 m2 for heat detectors. Preference isto be given to a symmetrical distribution of detectors.

b . For general purposes, detector spacing in accordance with the statutoryregulations (Clause 4.7d , Table 4.2 refers) is an adequate basis for protection.The spacing in Explosive Risk and other High Fire Risk areas shall be asspecified in Clause 4.4, Table 4.1.

c . In Electronic and Operational Spaces of High Value, close spacing of detectorsmay be necessary to enable early detection of small fires (which may causesubstantial damage and disruption) without unduly increasing the risk of falsefire signals. The air conditioning of such spaces will rapidly dilute thecombustion products from a fire, and the use of high sensitivity detectors is tobe considered. The recommendations of Table 6.2 have been abstracted fromBS 6266, for guidance. BS 6266 gives further guidance.

Application Area covered per detector

EDP equipment room,

(deckhead height about 3 m)

15 m2 to 25 m2

Tape stores 10 m2 to 30 m2

Electrical distribution boards

and emergency power supplies

10 m2 to 30 m2

Table 6.2 Recommended Coverage per Detector for EDP Installations

The smaller areas are recommended where the fire hazard is very high, or wherethere is a high rate of ventilation e.g. four changes per hour or more.

d . Where practicable, smoke detectors and probes located in ventilation trunkingare to be installed in a straight stretch, at a distance downstream from thenearest bend, corner or junction of at least three times the width of the ducting.Where the air from several extract points is combined into one duct, theinstallation of a detector adjacent to each abstract point is to be considered, toavoid delay in response due to dilution or stratification of smoke.


6.3

e . For electronic spaces fitted with false floors and deckheads (which may also beused for ventilation purposes), reference is to be made to BS 6266 for furtherguidance. Where there is a high fire hazard, the installation of detectors withinfloor and deckhead spaces, is to be considered.

6.4 Environment

a . Detectors are to be positioned and mounted so that they continue to operatecorrectly when subjected to the environmental hazards appropriate to theinstallation region in which they are installed in the HM Surface Ship orSubmarine, as defined in NES 1004. The fire detection system is to meet therequirements of DEF STAN 5941 for electromagnetic compatibility.

b . Detectors are to be positioned to avoid damage due to accidental impact. If thisis not possible the use of a protective guard is to be considered.

c . Fire detectors are essential items that are required to remain operational afterexperiencing shock to the maximum ship shock level. Preference is to be givento detectors and mountings that are sufficiently robust to be attached directlyto the ship or submarine structure. It is the responsibility of the DesignSponsor to agree the requirements for shock testing and the test severity, inaccordance with NES 1004.

d . If direct attachment is impractical or uneconomic, detectors are to be protectedby a shock mounting system of an approved type.

e . Detectors are to be positioned and mounted to minimize the occurrence of falsefire signals due to environmental effects. Known causes of false fire signalsinclude:

(1) Vibration, especially if in excess of the test levels of BS EN 54, Parts 7and 8;

(2) Ingress of foreign bodies, including small insects, dust and dirt;

(3) Air currents, high winds (especially ionization chamber detectors);

(4) High humidity, steam, condensation, icing;

(5) Corrosion of connections or other metal parts;

(6) Heat, smoke, flame, fumes from normal operations;

(7) Bright lights, photoflash, lightning discharge, reflections;

(8) Rapid increase in temperature following exposure to low temperatures;

(9) Flame detectors, if positioned so that they are pointing directlydownward, may be falsely activated by reflections from wet deck plates,this type of detector should be angled to give the best cone of vision overthe equipment considered to be a potential source of high fire risk (Dieselengines).

(10) Ionization smoke detectors manufactured by Thorn Security LimitedMF301NSN K4973133953 have been found to be susceptible to falseactivation caused by own ship HF transmissions or the radars of passingvessels.


6.4

Reference is to be made to BS EN 54, to ascertain the levels of environmentalstress which detectors, complying with that standard, may be expected towithstand without delivering a false fire signal.


a . Reference is to be made to Table 4.1, and other Paras of Section 4., for theregulation maximum spacing and location of detectors.

b . The Regulations require detectors to be located for optimum performance,avoiding positions near beams and ventilation ducts where airflow couldadversely affect performance. Positions where impact or physical damage islikely, are to be avoided. In general, detectors which are located overhead are tobe at least 0.5 m away from bulkheads.

c . In periodically unattended machinery spaces, the detectors must rapidly detectthe onset of fire under any normal condition of operation of the machinery, withvariations in temperature as required by the possible range of ambienttemperatures. After installation, the system is to be tested under varyingconditions.


7.1