Interior Communications and Alarms

Previous Page | Next Page

21.1 Interior communication circuits used for audible and visual signals and communication of information from one place to another, within or on the vessel shall comply with the following:

1. switches, resistors, connection boxes, accessories, instruments and other apparatus shall be of robust design and so installed as to ensure an ample margin of safety, having regard to the voltage employed;
2. where the voltage of supply exceeds 55 volts, switches, resistors, connection boxes, accessories, instruments and other apparatus shall be designed and installed throughout in all respects in accordance with the requirements applicable to power and lighting circuits;
3. cables shall be constructed and installed in accordance with the requirements of Sections 12 and 13; and
4. all circuits, other than those supplied from primary batteries shall be protected on each insulated pole by fuses of a current rating suited to the current rating of the circuit to be protected.

21.2 Wiring systems for interior communications essential for safety and for emergency alarm systems shall be arranged to avoid galleys, machinery spaces and other spaces having a high risk of fire except in so far as it is necessary to provide communication or to give alarm within those spaces.

21.3 On ships 500 gross tons or over, not equipped with bridge propulsion control and thus, where the engine order telegraph is the primary means of controlling speed and direction ahead or astern from the bridge, an audible and visual wrong direction alarm shall be provided in the engine room; similarly, on ships 500 gross tons or over, equipped with bridge propulsion control but also having an engine order telegraph for use when the ship is in engine room propulsion control, an audible and visual wrong direction alarm shall be provided in the engine room; the alarm shall operate whenever a control is operated in such a manner as to produce propulsive thrust in a direction opposite to that required by its engine order reply transmitter.

21.4 General Alarm System

21.4.1 General

A general alarm system shall be provided as required by the Hull Construction Regulations; consisting of either vibrating bells or electronic bell-like devices; the distribution system shall be arranged as follows, or as a function of the public address system in accordance with Subsection 21.5 but in no case shall be a combination of both systems.

21.4.2 Requirements

1. each general alarm device shall produce a signal or tone distinct from any other audible signal on the vessel; the signal or tone shall be of sufficient sound intensity provide adequate sound coverage in a compartment or space;
2. in certain areas where the ambient noise level is so high that audible devices alone would not be heard, they shall be augmented by flashing red lights or beacons which shall be of sufficient intensity and number and so located as to alert occupants of the space of an emergency; the flashing red lights or beacons shall be energized whenever the general alarm system with which they are associated is energized;
3. the audible devices shall be automatically silenced when a voice communication is transmitted over the public address system and shall also be arranged to automatically continue operation upon completion of the voice transmission;
4. the general alarm switch or contact maker shall be capable of remaining in the “on” position without supervision; the switch shall be located on the bridge at the main fire control panel adjacent to the public address system.
5. the wiring system shall be so arranged to avoid galleys, machinery spaces and other enclosed spaces having a high fire risk except in so far as it is necessary to provide sound coverage in such spaces or to reach the appropriate switchboard or distribution panel; and

21.4.3 Power Supply

1. the general alarm system shall be capable of operating continuously for a period of time in accordance with the duration requirements of the ship’s emergency power system as set forth in Schedule 1;
2. there shall be not less than two (2) independent sources of power supply reserved solely for the electrical equipment used in the operation of the general alarm system, one of which shall be an emergency source; such feeders shall run to an automatic change-over switch; or,
3. the system shall be arranged to operate on a floating battery in which the charging device shall be supplied from the final emergency power source; for those vessels because of design, operate the emergency services from individual batteries the charging device shall be supplied from the main switchboard essential services bus.
4. the general alarm feeder circuits shall be connected to the power source through fuses or circuit breakers which are fitted with one of the following:
   1. handles capable of being locked in the closed position; or
   2. an indicator light or alarm, at the main control station, which will indicate loss of power;

21.4.4 Distribution

1. The general alarm system shall have a feeder distribution panel provided to divide the system into the required number of zone feeders.
2. The feeder distribution panel shall be located in a space adjacent to the battery room if the power supply is a battery or in the emergency generator room if the power supply is the emergency generator.
3. There shall be at least one feeder circuit required for each vertical fire zone in which general alarm audible devices or flashing red lights or beacons are located;
4. There shall be provided for each vertical fire zone feeder a branch circuit distribution panel in which a minimum of one fused branch circuit provided for each deck level within the fire zone; the panel shall be located above the upper most continuous deck, or alternatively each deck branch circuit may terminate in the feeder distribution panel.
5. A deck branch circuit within a vertical fire zone shall not supply the audible devices and/ or lights or beacons on more than one deck level except where the levels of a space are common between decks;
6. Vessels which are not divided into vertical fire zones by main vertical bulkheads shall be divided into vertical fire zones not exceeding 40 metres and have a branch circuit provided for each deck level where general alarm audible device sand flashing red lights or beacons are required.

21.5 Public Address System

21.5.1 General A Public Address system shall be provided as required by the Hull Construction Regulations. The system shall provide effective means of communication throughout the accommodation, service spaces, machinery spaces control rooms muster and embarkation stations or both and in cargo ships of the self unloading type, the sound coverage shall include the tunnel areas and conveyor drive areas. This system may also provide the requirements for the general alarm system.

21.5.2 Requirements

1. the pubic address system controls shall be located adjacent to the general alarm controls at the main fire control station which shall be accessible to responsible members of the crew at all times whether in port or at sea.
2. the wiring system shall be so arranged to avoid galleys, machinery spaces and other enclosed spaces having a high fire risk except in so far as it is necessary to provide sound coverage in such spaces or to reach the appropriate switchboard or distribution panel.
3. a means shall be provided to silence all other audio distribution systems at the public address system station.
4. the overall performance of the system must not be effected by the failure of a single call station

21.5.3 Additional Requirements when Public Address System is employed as a General Alarm System

1. where the public address system amplifier is used to produce the signal or tone for the general alarm the contact maker shall activate all speakers in the system;
2. flashing red lights or beacons shall be supplied as required in accordance with Section 21 4.2(b);
3. the speakers shall not have external volume controls or local cut-out switches;
4. the amplifier and devices used to produce the signal or tone shall be duplicated.

21.5.4 Power Supply

1. there shall be not less than two (2) independent sources of power supply reserved solely for the electrical equipment used in the operation of the public address system; one of which shall be an emergency source; such feeders shall be run to an automatic change-over switch; or
2. the system shall be arranged to operate on a floating battery with the charging device supplied from the final emergency power source; for those vessels, because of design , operate the emergency services from individual batteries the charging device shall be supplied from the main switchboard essential services bus;
3. the public address system shall be capable of operating continuously for a period of time in accordance with the duration requirements of the ship’s emergency power system as set forth in Schedule 1;

21.5.5 Distribution (when employed as a combination Public Address and General System)

1. where the public address system is used to produce the emergency general alarm it shall be divided into the required number of vertical fire zones and deck circuits;
2. the distribution of the circuits shall be from the public address system amplifier cabinet and shall be located above the uppermost continuous deck, or from a branch distribution panel located in each vertical fire zone;
3. there shall be at least one circuit required for each vertical fire zone in which the loud speakers or flashing red lights or beacons are located;
4. each branch circuit shall be protected against short circuit and shall not supply speakers or beacons on more than one deck level except where the levels of a space are common between decks;
5. on vessels not divided into fire zones by main vertical fire bulkheads, the vessel shall be divided into vertical zones not exceeding 40 metres in length and a branch alarm circuit provided for each such zone and on each deck where general alarm speakers or red flashing beacons are required.

21.6 Automatic Fire Detection and Fire Alarm Systems

21.6.1 General An automatic and manual fire detection and fire alarm system shall be provided as required by the Hull Construction Regulations and shall be arranged as follows:

21.6.2 General Requirements:

1. any automatic fire detection and fire alarm system with manually operated call points shall be capable of immediate operation at all times;
2. power supplies and electric circuits necessary for the operation of the system shall be monitored for loss of power or fault conditions as appropriate; occurrence loss of power of a fault condition shall initiate a visual and audible fault signal at the control panel and remote indicating units which shall be distinct from a fire signal;
3. there shall be not less than two sources of power supply for the electrical equipment used in the operation of the fire detection and fire alarm system, one of which shall be an emergency source; a visual and audible alarm signal at the control panel and remote indicating units shall indicate when the normal supply has failed and the system is operating on the emergency or battery supply;
4. the power supply shall be provided by separate feeders reserved solely for that purpose and such feeders shall run to an automatic changeover switch situated in or adjacent to the control panel for the fire detection system, or the system shall be arranged to operate on a dedicated floating battery with the charging device supplied from the final emergency power source and, shall be capable of operating continuously for a period of time in accordance with Schedule 1;
5. detectors and manual call points shall be grouped into sections and the activation of any detector or manual call point shall initiate a visual and audible fire signal at the main control panel and remote indicating units;
6. if the signals have not received attention within two minutes, an audible alarm shall be automatically sounded throughout the crew accommodation and service spaces, control stations and machinery spaces of Category ‘A’;
7. the alarm sounder system need not be an integral part of the detection system and may be part of the general alarm system; in passenger ships the audible devices shall be capable of being sounded independently of the alarm to the passenger spaces;
8. the alarm devices shall be automatically silenced when a voice communication is transmitted over the public address system and shall also be arranged to automatically continue operation upon completion of the voice transmission;
9. the control panel shall be located on the navigating bridge or in the main fire control station;
10. indicating units shall denote the section in which a detector or manual call point or circuit fault has operated or in the case of the addressable fire detection system the device that has been operated or location in which a fault has occurred; at least one unit shall be so located that it is easily accessible to responsible members of the crew at all times, when at sea or in port except when the ship is out of service;
11. one indicating unit shall be located on the navigating bridge if the control panel is located in the main fire control station;
12. clear information shall be displayed on or adjacent to each indicating unit about the spaces covered and the location of the sections;
13. no section of detectors installed on a zone circuit covering more than one deck within accommodation, service and control stations shall normally be permitted except a section which covers an enclosed stairway;
14. each loop circuit shall be divided into sections; each section shall be separated by a device which will ensure that if a short circuit or fault occurs anywhere within the loop only the affected section will be isolated from the rest of the circuit; no section between these devices shall include more than fifty (50) devices; a section of detectors which is installed in a loop circuit shall not be situated in more than one vertical fire zone; where more than one loop circuit is provided within a vertical fire zone they shall be so arranged that each deck level is not served by more than one circuit;
15. in order to avoid delay in identifying the source of fire, the number of enclosed spaces included on each zone circuit shall be limited shall be limited and in no case shall more than fifty enclosed spaces be permitted in any section;
16. in passenger ships, a section of detectors on a zone circuit shall not serve spaces on both sides of the ship nor on more than one deck and neither shall it be situated in more than one main vertical zone except that, if the protection of the ship against fire will not thereby be reduced, such a section of detectors may be permitted to serve both sides of the ship and more than one deck;
17. a section of fire detectors on a zone or loop circuit which covers a control station, a service space or an accommodation space shall not include a machinery space of Category ‘A’;
18. detectors shall be operated by heat, smoke or other products of combustion, flame, or any combination of these factors; detectors operated by other factors indicative of incipient fires may be considered provided that they are no less sensitive than such detectors; flame detectors shall only be used in addition to smoke or heat detectors;
19. suitable instructions and components spares for testing and maintenance shall be provided; spare detector heads shall be carried in the proportion of not less than one for each 50 heads fitted in the installation with a minimum of six heads;
20. the function of the detection system shall be periodically tested by means of equipment producing hot air at the appropriate temperature, or smoke or aerosol particles having the appropriate range of density or particle size, or other phenomena associated with incipient fires to which the detector is designed to respond; all detectors shall be of a type such that they can be tested for correct operation and restored to normal surveillance without the renewal of any component; and
21. the fire detection system shall not be used for any other purpose, except that closing of fire doors and similar functions at the fire control panel in accordance with the Fire Protection, Detection and Extinguishing Equipment Regulations;
22. where an addressable fire detection system has been provided with a feature to temporarily isolate a section from the monitoring system, due to repairs to the system or the vessel in the vicinity of the section, a visual flashing signal and an audible signal on a timed cycle of once every thirty (30) minutes shall be provided to alert the crew the system is isolated and to reactivate the section to a normal surveillance state upon the completion of the repairs;
23. an addressable fire detection system shall be so designed that the first alarm will not prevent the initiating of any subsequent alarms;
24. all arrangements are to be made to enable the initial configuration of the system to be restored in the event of failure.(electrical, electronic, informatic);

21.6.3 Installation Requirements:

1. manual call points shall be installed throughout the accommodation and public spaces, service spaces and control stations; one manual call point shall be located at each exit; manual call points shall be readily accessible in the corridors of each deck such that no part of the corridor is more than 20 m from a manual call point;
2. subject to paragraph 21.6.2 smoke detectors shall be installed in cabins, corridors, escape routes, stairways and service spaces; consideration shall be given to the installation of special purpose smoke detectors within ventilation ducting;
3. heat detectors shall be installed in public rooms, galleys and pantries containing cooking appliances;
4. where a fire detection and fire alarm system is required for the protection of spaces other than those specified in paragraph 21.6 (2) , at least one detector complying with sub-paragraph 21.6 (2) (xviii) shall be installed in each such space;
5. detectors shall be located for optimum performance; positions near beams and ventilation ducts or other positions where patterns of air flow could adversely affect performance and positions where impact or physical damage is likely shall be avoided; in general, detectors which are located on the overhead shall be a minimum distance of 0.5 m away from bulkheads;
6. the standard maximum spacing of detectors is noted in the following table; where detectors are installed which exceed these spacings they shall be certificated by a certifying authority which confirms the detector safely covers the space specified and details of the detector’s certification shall be submitted for inspection.
   1. Heat Detector
      Maximum floor area per detector: 37 m²
      Maximum distance apart between centres: 9 m
      Maximum distance away from bulkheads: 4.5 m
   2. Smoke Detector
      Maximum floor area per detector: 74 m²
      Maximum distance apart between centres: 11 m
      Maximum distance away from bulkheads: 5.5 m
7. electrical wiring which forms part of the system shall be so arranged as to avoid galleys, machinery spaces of Category ‘A’, and other enclosed spaces of high fire risk except where it is necessary to provide for fire detection or alarm in such spaces or to connect to the appropriate power supply; and

21.6.4 System Design Requirements:

1. the system and equipment shall be suitably designed to withstand supply voltage variation and transients, ambient temperature changes, vibration, humidity, shock, impact and corrosion normally encountered in ships;
2. smoke detectors required by sub-paragraph 21.6 (3) (ii) shall be certified to operate before the smoke density exceeds 12.5 per cent obscuration per metre, but not until the smoke density exceeds 2 per cent obscuration per metre; smoke detectors to be installed in other spaces shall operate with sensitivity limits having regard to the avoidance of detector insensitivity or oversensitivity;
3. heat detectors shall be certified to operate before the temperature exceeds 78° C but not until the temperature exceeds 54° C , when the temperature is raised to these limits at a rate less than 1° C per minute; at higher rates of temperature rise, the heat detector shall operate within temperature limits having regard to the avoidance of detector insensitivity or oversensitivity; and
4. in drying rooms and similar spaces of a normal high ambient temperature, the permissible temperature of operation of heat detectors may be increased to 30° C above the maximum deckhead temperature;
5. when detectors are provided with means to adjust their sensitivity, the arrangements are to be such that the set points can be fixed and readily identified.

21.7 Where arrangements are provided for fire doors to be held in the open position by means of energized electro-magnets, they shall be controlled from a central control point as required by the Hull Construction Regulations; they shall also be capable of release at each door; such devices shall be arranged to “fail-safe”, for example , they shall cause the door to close in the event of their failure;

1. when the arrangements incorporate direct acting solenoids, they shall be capable of exerting a pull which equates to at least half the weight of the door, plus that force required to overcome any self-closing mechanism, thus being capable of holding the door open under a possible rolling condition of up to at least 15° either way; other retaining devices, e.g. solenoid controlled latches, shall be capable of exerting a restraint equivalent to the above; when de-energized, the residual magnetism shall not be so great as to impede the door from closing at inclinations of 3½° either way;
2. the solenoid coils shall be rated for continuous operation;
3. solenoids, when de-energized, shall release the doors from both the remote or local position and the solenoids must remain de-energized so that should the door thereafter be opened, it would not be retained in the open position;
4. grouping of release circuits shall be so arranged that doors bounding, or lying in a main fire zone should normally be grouped together, and follow the same group nomenclature as the fire alarm indicators;
5. local switches, and the group release switches at the main fire control station, shall be of the “on-off” type so that the solenoids remain de-energized when the switches are operated, until deliberately re-set after an emergency;
6. a switch on each side of the door is to be preferred, but if only one switch is provided at each local door switching position, it shall be easily accessible and conspicuous to anyone passing through the door opening;
7. an indication system which shows the “door open” and “door closed” condition shall be provided at the main control panel; and
8. the device giving “door closed” indication shall only operate on the final movement of closing.

Previous Page | Next Page