Section 4 Fire detection and fire alarm systems
Clasification Society 2024 - Version 9.40
Clasifications Register Rules and Regulations - Rules and Regulations for the Classification of Naval Ships, January 2023 - Volume 2 Machinery and Engineering Systems - Part 9 Electrotechnical Systems - Chapter 9 Fire Safety and Ship Safety Systems - Section 4 Fire detection and fire alarm systems

Section 4 Fire detection and fire alarm systems

4.1 General

4.1.1 Fire detection and alarm systems are to comply with Chapter 9 – Fixed fire detection and fire alarm systems of the Fire Safety Systems Code (FSS Code) and Vol 2, Pt 9, Ch 9, 4.1 General 4.1.3 to Vol 2, Pt 9, Ch 9, 4.1 General 4.1.15.

4.1.2 Fire detection control units, indicating panels, detector heads, manual call points and short-circuit isolation units are to be Type Approved in accordance with Test Specification Number 1 given in LR’s Type Approval System for an environmental category appropriate for the locations in which they are intended to operate. For addressable systems, see also Vol 2, Pt 9, Ch 8, 5 Programmable electronic systems (PES).

4.1.3 An audible fire-alarm is to be provided having a characteristic tone distinguishing it from the alarm system required by Vol 2, Pt 9, Ch 7, 4.3 Alarm systems, general requirements or any other alarm system. The audible fire-alarm is to be immediately audible throughout the machinery spaces, the navigating bridge and at manned watch positions as designated by the specified fire safety standard. Facilities are to be provided in the fire detection system to initiate manually the fire-alarm from positions adjacent to all exits from machinery spaces, the navigating bridge and manned watch positions as designated by the specified fire safety standard.

4.1.4 Fire detection and alarm systems are to be provided with at least two power supplies. One supply is to be connected to the main source of electrical power and another supply is to be connected to the emergency source of electrical power required by Vol 2, Pt 9, Ch 2, 5.2 Emergency source of electrical power, or an accumulator battery capable of supplying power for the same period of time as the emergency source of electrical power. All power supply feeders for fire detection and alarm systems are to be in accordance with Vol 2, Pt 9, Ch 3, 8.6 Conductor size 8.6.4.

4.1.5 Automatic changeover facilities in accordance with Vol 2, Pt 9, Ch 3, 4.3 Isolation and switching 4.3.4 are to be located in, or adjacent to, the main fire-control panel. Power supply changeover is to be achieved without adverse effect. Failure of any power supply is to operate an audible and visual alarm. See also Vol 2, Pt 9, Ch 3, 8.10 Cable support systems 8.10.6 Vol 2, Pt 9, Ch 3, 8.10 Cable support systems 8.10.7 and Vol 2, Pt 9, Ch 1, 2.5 Operation under fire conditions.

4.1.6 Where an accumulator battery provides a power supply, on restoration of the main source of electrical power, the rating of the charge unit is to be sufficient to recharge the battery while maintaining the output supply to the fire detection and alarm system.

4.1.7 Power supplies from the main and emergency switchboards are to be supplied by separate feeders that are reserved solely for this purpose. Where the emergency feeder for the electrical equipment used in the operation of the fixed fire detection and alarm system is supplied from the emergency switchboard, it is to be run from this switchboard to the automatic changeover switch without passing through any other switchboard.

4.1.8 The fixed fire detection and fire-alarm systems are to be capable of remotely and individually identifying each detector and manually operated call point. At least one indicating unit is to be so located that it is easily accessible to responsible members of the crew. One indicating unit is to be located on the navigating bridge if the control panel is located in the central control station.

4.1.9 A loop circuit of an addressable fire detection system, capable of remotely identifying from either end of the loop each detector and manually operated call point served by the circuit, may serve spaces on both sides of the ship and on several decks, but is not to be situated in more than one main vertical or horizontal fire zone, nor is a loop circuit which covers an accommodation space, service space and/or control station to include a machinery space of Category A.

4.1.10 A loop circuit of an addressable fire detection system may comprise one or more sections. Where the loop comprises more than one section, the sections are to be separated by devices which will ensure that, if a short-circuit occurs anywhere in the loop, only the affected section will be isolated from the control panel. No section of detectors and manually operated call points is, in general, to include more than 50 detectors.

4.1.11 Detectors and manually operated call points are to be grouped into sections. The activation of any detector or manually operated call point is to initiate a visual and audible fire-alarm signal at the control panel and indicating units.

4.1.12 A section of detectors of an addressable fire detection system is neither to serve spaces on both sides of the ship nor on more than one deck, except that:

4.1.13 a section of detectors may serve spaces on more than one deck if those spaces are located in either the fore and aft end of the ship or they constitute common spaces occupying several decks, i.e. personnel spaces, enclosed stairways, etc.

4.1.14 in ships of less than 20 m in breadth, a section of detectors may serve spaces on both sides of the ship.

4.1.15 A section of fire detectors and manually operated call points of an addressable system is not to be situated in more than one main vertical zone.

4.1.16 A section of fire detectors and manually operated call points which covers a control station, a service space or an accommodation space is not to include a machinery space of Category A.

4.1.17 The wiring for each section of detectors and manually operated call points in an addressable fire detector system is to be separated as widely as practicable from that of all other sections on the same loop.

4.1.18 When it is intended that a particular loop is to be temporarily switched off, this state is to be clearly indicated at the fire detection indicating panels.

4.1.19 An audible fire-alarm is to be provided having a characteristic tone distinguishing it from any other alarm system. Facilities are to be provided in the fire detection system to initiate manually the fire-alarm from positions adjacent to all exits from machinery spaces, the navigating bridge and manned watch positions as designated by the Naval Administration.

4.1.20 Activation of any detector or manually operated call point in a machinery space is to result in immediate activation of the audible fire alarm throughout that machinery space, the navigating bridge and at manned watch positions as designated by the Naval Administration.

4.1.21 The activation of any detector or manually operated call point is to initiate a visual and audible fire-alarm signal at the control panel and indicating units. If the signals have not received attention within two minutes an audible alarm is to be automatically sounded throughout the crew accommodation and service spaces, control stations and machinery spaces of Category A. This alarm sounder system need not be an integral part of the detection system.

4.1.22 The fixed fire detection system is to be capable of remotely and individually identifying each detector and manually operated call point. At least one indicating unit is to be so located that it is easily accessible to responsible members of the crew. One indicating unit is to be located on the navigating bridge if the control panel is located in the central control station.

4.1.23 The fire alarm system is to be designed with self-monitoring properties. Power or system failures are to initiate an audible alarm distinguishable from the fire-alarm. This alarm may be incorporated in the machinery alarm system as required by Vol 2, Pt 9, Ch 7, 4.3 Alarm systems, general requirements.

4.1.24 Where it is intended that detectors be installed in external locations, in addition to meeting the requirements for an environmental category suitable for open decks, see Vol 2, Pt 9, Ch 9, 4.1 General 4.1.26, they are also to be tested for sun irradiation and ultraviolet exposure with satisfactory results.

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

4.1.26 The fire detector heads are to be of a type which can be tested and reset without the renewal of any component. Facilities are to be provided on the fire-control panel for functional testing and reset of the system.

4.1.27 When it is intended that a particular detector(s) is to be temporarily switched off locally, this state is to be clearly indicated at the local position. Reactivation of the detector(s) is to be performed automatically after a preset time.

4.1.28 It is to be demonstrated to the Surveyor’s satisfaction that detector heads are so located that air currents will not render the system ineffective whether the ship is at sea or in port.

4.1.29 Detector heads are to be located in the machinery spaces so that all potential fire outbreak points are guarded. A combination of detectors is to be provided to ensure that the system will react to all possible fire characteristics.

4.1.30 Fire detection indicating panels are to denote the section in which a detector or manually operated call point has operated. At least one indicating panel is to be located on the navigating bridge unless specified otherwise by the Naval Administration.

4.1.31 A fire detection control unit is to be located in the navigating bridge area, the fire-control station, or in some other position such that a fire in the machinery spaces will not render it inoperable.

4.1.32 Clear information is to be displayed on or adjacent to each indicating unit about the spaces covered and the location of the section and, for passenger ships, each detector and manually operated call point.

4.1.33 The fire detection system is not to be used for any other purpose, except that closing of fire doors and similar functions may be permitted at the control panel.

4.1.34 Sound signal equipment, fire and general alarm bells are to be supplemented by visual indication, areas having high levels of background noise, such as machinery spaces.


Copyright 2022 Clasifications Register Group Limited, International Maritime Organization, International Labour Organization or Maritime and Coastguard Agency. All rights reserved. Clasifications Register Group Limited, its affiliates and subsidiaries and their respective officers, employees or agents are, individually and collectively, referred to in this clause as 'Clasifications Register'. Clasifications Register assumes no responsibility and shall not be liable to any person for any loss, damage or expense caused by reliance on the information or advice in this document or howsoever provided, unless that person has signed a contract with the relevant Clasifications Register entity for the provision of this information or advice and in that case any responsibility or liability is exclusively on the terms and conditions set out in that contract.