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Fire detection systems

In document Indian Coast Guard Ships (Page 179-182)

Fire Detection and Extinguishing Systems

5.1 Fire detection systems

tight division, a smoke damper is to be fitted at the penetration unless the duct which passes through the space does not serve that space.

The fire and smoke dampers are to be easily accessible. Where they are placed behind ceilings or linings, they are to be provided with an inspection door on which a plate is fitted providing the identification number of the damper. Such plates with identification numbers are also to be placed on any required remote controls.

4.5 Where ventilation systems penetrate decks, the arrangements are to be such that the effectiveness of the deck in resisting fire is not thereby impaired and precautions are to be taken to reduce the likelihood of smoke and hot gases passing from one between deck space to another through the system.

4.6 All dampers fitted on fire-resisting or smoke-tight divisions are also to be capable of being manually closed from each side of the division in which they are fitted, except for those dampers fitted on ducts serving spaces not normally manned such as stores and toilets that may be manually operated only from outside the served spaces. All dampers are also to be capable of being remotely closed from the continuously manned control station.

Manual closing may be achieved by mechanical means of release or by remote operation of the fire or smoke damper by a fail-safe electrical switch or pneumatic release (i.e. spring-loaded, etc.) 4.7 Ducts are to be made of non-combustible material.

4.8 Where additional class notation ‘Fire zones’ is to be assigned, the requirements of independent ventilation systems and smoke extraction systems of Part 6, Chapter 8 of the Rules and Regulations for the Construction and Classification of Steel Ships are to be complied with.

Section 5

source. The supply is to be provided by separate feeders reserved solely for this purpose.

Such feeders are to run to an automatic change over switch situated in or adjacent to the control panel for the fire detection system;

d) 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 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 accommodation and service spaces, control stations and machinery spaces. There shall be no time delay for the audible alarms in crew accommodation areas when all the control stations are unattended. The alarm sounder system need not be an integral part of the detection system;

e) The control panel is to be located in the navigation bridge or in the main fire control station or in the machinery control station;

f) Indicating units are to, as a minimum, denote the section in which a detector or manually operated call point has operated. At least one unit is to be so located that it is easily accessible to responsible members of the crew at all times.. One indicating unit is to be located in the navigation bridge if the control panel is located in the space other than the navigation bridge;

g) Clear information is to be displayed on or adjacent to each indicating unit about the spaces covered and the location of the sections;

h) A section of fire detectors which covers a control station, a service space, accommodation space, corridor or stairway enclosure are not to include a machinery space of major fire hazard. For fire detection systems with remotely and individually identifiable fire detectors, the requirement set out in this paragraph is considered met when a loop covering accommodation spaces, service spaces and control stations, does not include spaces of a major fire hazard;

i) Detectors are to 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 are only to be used in addition to smoke or heat detectors;

j) Suitable instructions and component spares for testing and maintenance are to be provided;

k) The function of the detection system is to 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 are to be of a type such that they can be tested for correct operation and restored to normal surveillance without the renewal of any component;

l) The fire detection system is not be used for any other purpose, except that following functions may be permitted at the control panel:

- To activate a paging system;

- To activate the fan stops;

- To activate the closure of fire doors;

- To activate the closure of fire and smoke dampers;

- To activate the sprinkler system.

m) Fire detection systems with a zone address identification capability are to be so arranged that;

Indian Register of Shipping

- a loop cannot be damaged at more than one point by a fire. For this purpose loop is not to pass through a space twice. Where this is not practical the part of the loop which by necessity passes through the space for a second time is to be installed at the maximum possible distance from the other parts of the loop;

- means are provided to ensure that any fault (e.g. power break; short circuit; earth) occurring in the loop will not render the whole loop ineffective;

- all arrangements are made to enable the initial configuration of the system to be restored in the event of failure (electrical, electronic, informatic); and

- the first initiated fire alarm is not to prevent any other detector to initiate further fire alarms.

5.1.2 Installation Requirements of Fire Detection Systems

a) In addition to 5.1, manually operated call points are to be readily accessible in the corridors of each deck such that no part of the corridor is more than 20 [m] from a manually operated call point;

b) Where a fixed fire detection and fire alarm system is required for the protection of spaces other than stairways, corridors and escape routes, at least one detector complying with 5.1.1 i) is to be installed in each such space;

c) Detectors are to 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 should be avoided. In general, detectors, which are located on the deckhead, are to be a minimum distance of 0.5 [m]

away from bulkheads. Distances smaller than 0.5 [m] from bulkheads may be accepted in corridors, lockers and stairways.

d) The maximum spacing of detectors are to be in accordance with the table below:

Type of detector Max. floor area per detector [m2]

Max. distance apart between centres [m]

Max. distance away from bulkheads [m]

Heat 37 9 4.5

Smoke 74 11 5.5

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

e) Electrical wiring which forms part of the system is to be so arranged as to avoid spaces of major fire hazard, except, where it is necessary, to provide for fire detection or fire alarm in such spaces or to connect to the appropriate power supply.

5.1.3 Design Requirements of Fire Detection Systems

a) The system and equipment are to be suitably designed to withstand supply voltage variation and transients, ambient temperature changes, vibration, humidity, shock, impact and corrosion normally encountered in ships;

b) Smoke detectors are to be certified to operate before the smoke density exceeds 12.5%

obscuration per metre, but not until the smoke density exceeds 2% obscuration per metre.

c) Heat detectors are to be certified to operate before the temperature exceeds 78oC but not until the temperature exceeds 54oC, when the temperature is raised to those limits at a rate less than 1oC per minute. At higher rates of temperature rise, the heat detector is to operate

Indian Register of Shipping

within temperature limits having regard to the avoidance of detector insensitivity or over- sensitivity;

d) The permissible temperature of operation of heat detectors may be increased to 30oC above the maximum deckhead temperature in drying rooms and similar space of a normal high ambient temperature;

e) Flame detectors referred in 5.1.1 i) are to have sensitivity sufficient to determine flame against an illuminated space background and a false signal identification system.

5.1.4 Additional Requirements for Fixed Fire Detection and Fire Alarm System for periodically unattended machinery spaces:

a) The fire detection system is to be so designed and the detectors so positioned as to detect rapidly the onset of fire in any part of those spaces and under any normal conditions of operation of the machinery and variations of ventilation as required by the possible range of ambient temperatures. Except in spaces of restricted height and where their use is especially appropriate, detection system using only thermal detectors is not permitted. The detection system is to initiate audible and visual alarms distinct in both respects from the alarms of any other system not indicating fire, in sufficient places to ensure that the alarms are heard and observed on the navigating bridge and by a responsible engineer officer.

When the navigation bridge is unmanned the alarm is to sound in a place where a responsible member of the crew is on duty; The alarm is also to sound in the a place where a responsible member of the crew is on duty even in harbour condition when the navigation bridge may be unmanned.

b) After installation, the system is to be tested under varying conditions of engine operation and ventilation.

In document Indian Coast Guard Ships (Page 179-182)