Section 2 Fire Detection and Extinction

201. Fire detection and extinguishing systems

1. Areas of major and moderate fire hazard and other enclosed spaces not regularly occupied within public spaces and crew accommodation, such as toilets, stairway enclosures, corridors and escape routes are to be provided with an approved automatic smoke detection system and manually oper- ated call points to indicate at the control station the location of outbreak of a fire in all normal operating conditions of the installations. Detectors operated by heat instead of smoke may be in- stalled in galleys. Main propulsion machinery room(s) is to, in addition, have detectors sensing oth- er than smoke and be supervised by TV cameras monitored from the operating compartment. Manually operated call points are to be installed throughout the public spaces, crew accommodation, corridors and stairway enclosures, service spaces and where necessary control stations. One man- ually operated call point is to be located at each exit from these spaces and from areas of major fire hazard.

2. The fixed fire detection and fire alarm systems are to comply with the following.

(1) General requirements

(A) Any required fixed fire detection and fire alarm system with manually operated call points are to be capable of immediate operation at all times.

(B) Power supplies and electric circuits necessary for the operation of the system are to be monitored for loss of power or fault conditions as appropriate. Occurrence of a fault con-

dition is to initiate a visual and audible fault signal at the control panel which is to be dis-

tinct form a fire signal.

(C) Not less than two sources of power supply for the electrical equipment used in the oper- ation of the fixed fire detection and fire alarm systems, one of which is an emergency

source. The supply is to be provided by separate feeders reserved solely for that 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 crew accom- modation and service spaces, control stations and machinery spaces. There is to 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 operating compartment or in the main fire control station.

(F) Indicating units are, as a minimum, to 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 ac- cessible to responsible members of the crew at all times, when at sea or in port, except when the craft is out of service. One indicating unit is to be located in the operating com- partment if the control panel is located in the space other than the operating compartment.

(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) Where the fire-detection system does not include means of remotely identifying each de-

tector individually, no section covering more than one deck within public spaces, crew ac- commodation, corridors, service spaces and control stations is normally to be permitted ex-

cept a section which covers an enclosed stairway. In order to avoid delay in identifying

the

(I)

(J)

source of fire, the number of enclosed spaces included in each section is to be limited. In

no case is to more than 50 enclosed spaces be permitted in any section. If the detection system is fitted with remotely and individually identifiable fire detectors, the sections may cover several decks and serve any number of enclosed spaces.

In passenger craft, if there is no fire detection system capable of remotely and individually identifying each detector, a section of detectors is not to serve spaces on both sides of the craft nor on more than one deck and neither should it be situated in more than one zone according to Ch 1, 301. 1, if it is satisfied that the protection of the craft against fire will not thereby be reduced, may permit such a section of detectors to serve both sides of the craft and more than one deck. In passenger craft fitted with individually identifiable fire de- tectors, a section may serve spaces on both sides of the craft and on several decks.

A section of fire detectors which covers a control station, a service space, a public space, crew accommodation, corridor or stairway enclosure is not to include a machinery space of major fire hazard.

(K) 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 by the Society provided that they are no less sensitive than such detectors. Flame detectors are only to be used in addition to smoke or heat detectors.

(L) Suitable instructions and component spares for testing and maintenance are to be provided.

(M) The function of the detection system is to be tested periodically by means of equipment

producing hot air at appropriate range of

the appropriate temperature, or smoke or aerosol particles having the 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.

(N) 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.

(O) Fire detection systems with a zone address identification capability are to be so arranged

that.

(a)

A loop cannot be damaged at more than one point by a fire, 【See Guidance】

(b) Means are provided to ensure that any fault (e.g., power break; short circuit; earth) oc- curring in the loop is not to render the whole loop ineffective, 【See Guidance】

(c)

All arrangements are made to enable the initial configuration of the system to be re-

stored in the event of failure (electrical, electronic, informatic), and

(d) The first initiated fire alarm is not to prevent any other detector to initiate further fire alarms.

(2) Installation requirements

(A) 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 (1),

(K) 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 are to be avoided. In general, detectors which are located on the overhead are to be a minimum distance of 0.5 m away from

bulkheads.

(D) The maximum spacing of detectors is to be in accordance with the table below.

The Society may require or permit other spacings 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 machinery

spaces of major fire hazard, and other enclosed spaces of major fire hazard except, where it is necessary, to provide for fire detection of fire alarm in such spaces or to connect to the appropriate power supply.

(3) Design requirements

(A) The system and equipment is to be suitably designed to withstand supply voltage variation and transients, ambient temperature changes, vibration, humidity, shock, impact and corrosion normally encountered in crafts.

(B) Smoke detectors required by (2), (B) above 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. Smoke detectors to be installed in other spaces are to operate within sensitivity limits to the satisfaction of the Society having regard to the avoidance of detector insensitivity or oversensitivity.

(C) Heat detectors are to be certified to operate before the temperature exceeds 78℃ but not

until the temperature exceeds 54℃, when the temperature is raised to those limits at a rate

less than 1℃ per minute. At higher rates of temperature rise, the heat detector is to operate

within temperature limits, having regard for the avoidance of detector insensitivity or

over-sensitivity.

(D) The permissible temperature for the operation of heat detectors may be increased to 30℃

above the maximum deckhead temperature in drying rooms and similar spaces of a normal

high ambient temperature.

(E) Flame detectors referred to in (1), (K) are to have a sensitivity sufficient to determine flame

against an illuminated space background and a false signal identification system.

3. A fixed fire detection and fire alarm system for periodically unattended machinery spaces (including machinery spaces in which watchkeeping personnel is not in place continuously or in which person- nel location is impossible due to narrow structures under the Society's consideration, hereinafter the same applies) is to comply with the following.

(1) The fire detection system is to be so designed, and the detectors so positioned as to detect rap- idly 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 to be 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 operating compartment is un- manned, the alarm is to sound in a place where a responsible member of the crew is on duty.

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

4. Areas of major fire hazard are to be protected by an approved fixed fire-extinguishing system oper- able from the control position which is adequate for the fire hazard that may exist. The system is to comply with 201. 6 and be capable of local manual control and remote control from the con- tinuously manned control stations. 【See Guidance】

5. In all craft where gas is used as the extinguishing medium, the quantity of gas is to be sufficient to provide two independent discharges. The second discharge into the space is only to be activated manually from a position outside the space being protected. Where the space has a local fire-sup-

pression system installed to protect fuel oil, lubricating oil and hydraulic oil located near exhaust manifolds, turbo chargers or similar heated surfaces on main and auxiliary internal combustion en- gines, a second discharge need not be required. 【See Guidance】

6. Requirements for fixed fire-extinguishing systems

(1) General

(A) The use of a fire-extinguishing medium which, either by itself or under expected conditions of use, will adversely affect the earth's ozone layer, and/or gives off toxic gases in such quantities as to endanger people, is not to be permitted.

(B) The necessary pipes for conveying fire-extinguishing medium into protected spaces are to be provided with control valves so marked as to indicate clearly the spaces to which the pipes are led. Non-return valves are to be installed in discharge lines between cylinders and manifolds. Suitable provision is to be made to prevent inadvertent admission of the medium into any space.

(C) The piping for the distribution of fire-extinguishing medium is to be arranged, and discharge nozzles so positioned, that a uniform distribution of medium is obtained.

(D) Means are to be provided to close all openings which may admit air to, or allow gas to es-

cape from, a protected space.

(E) Where the volume of free air contained in air receivers in any space is such that, if re- leased in such space in the event of fire, such release of air within that space would seri- ously affect the efficiency of the fixed fire-extinguishing system, the provision of an addi- tional quantity of fire-extinguishing medium is to be required.

(F) Means are to be provided for automatically giving audible warning of the release of fire-ex- tinguishing medium into any space in which personnel normally work or to which they have access. The alarm is to operate for a suitable period before the medium is released, but not

less than 20s. Visible alarm is to be arranged in addition to the audible alarm.

(G) The means of control of any fixed gas fire-extinguishing system are to be readily accessible and simple to operate, and are to be grouped together in as few locations as possible at po- sitions not likely to be cut off by a fire in a protected space. At each location there are to be clear instructions relating to the operation of the system having regard to the safety of personnel.

(H) Automatic release of fire-extinguishing medium is not permitted. 【See Guidance】

(I) Where the quantity of extinguishing medium is required to protect more than one space, the quantity of medium available need not be more than the largest quantity required for any one space so protected.

(J) Pressure containers required for the storage of fire-extinguishing medium are to be outside protected spaces in accordance with (M) below. Pressure containers may be inside the space to be protected if in the event of accidental release persons will endangered.

(K) Means are be provided for the crew to safely check the quantity of medium containers.

located located not be

in the

(L) Containers for the storage of fire-extinguishing medium and associated pressure components

are to be designed in accordance with Pt 5, Ch 5 of Rules for the Classification of Steel Ships with regard to their locations and maximum ambient temperatures expected in service.

(M) When the fire-extinguishing medium is stored outside a protected space, it is to be stored in a room which is to be situated in a safe and readily accessible position and is to be effec-

tively ventilated. Any entrance to such a storage room is preferably to be from the open

deck, and in any case should be independent of the protected space. Access doors are to open outwards, and bulkheads and decks including doors and other means of closing any opening therein, which form the boundaries between such rooms and adjoining enclosed spaces, are to be gas tight. Such storage rooms are to be treated as control stations.

(N) Spare parts for the system are to be stored on board or at a base port.

(O) If the release of a fire extinguishing medium produces significant over or under pressuriza- tion in the protected space, means are to be provided to limit the induced pressures to ac-

ceptable limits to avoid structural damage.

(2) Carbon dioxide systems

(A) For cargo spaces, the quantity of carbon dioxide available is, unless otherwise provided, to be

the largest cargo space so protected in the craft.

(B) For machinery spaces, the quantity of carbon dioxide carried is to be sufficient to give a minimum volume of free gas equal to the larger of the volumes of (a) or (b) below.

(a) 40 % of the gross volume of the largest machinery space so protected, the volume to exclude that part of the casing above the level at which the horizontal area of the cas-

ing is 40 % or less of the horizontal area of the space concerned taken midway be- tween the tank top and the lowest part of the casing.

(b) 35 % of the gross volume of the largest machinery space protected, including the casing.

(c)

For the purpose of this requirement, the volume of free carbon dioxide is to be calcu-

lated at 0.56

(d) m kg.

For machinery spaces, the fixed piping system is to be such that 85 % of the gas can

(e)

(f)

be discharged into the space within 2 minutes.

Two separate controls are to be provided for releasing carbon dioxide into a protected space and to ensure the activation of the alarm. One control is to be used to discharge the gas from its storage containers. A second control is to be used for opening the valve of the piping which conveys the gas into the protected spaces.

The two controls are to be located into a release box clearly identified for the particular space. If the box containing the controls is to be locked, a key to the box is to be in

a break-glass type enclosure conspicuously located adjacent to the box. The percentages

in (a) and (b) above may be reduced to 35 % and 30 % respectively for cargo craft of less than 2,000 tons gross tonnage; provided also that if two or more machinery spaces

7. Control stations, public spaces, crew accommodation, corridors and service spaces are to be pro- vided with portable fire extinguishers of approved type and design. At least five portable ex- tinguishers are to be provided, and so positioned, as to be readily available for immediate use. In addition, at least one extinguisher suitable for machinery space fires is to be positioned outside each machinery space entrance.

8. Fire pumps, and appropriate associated equipment, or alternative effective fire extinguishing systems are be fitted as follows.

(1) At least two independently driven pumps are to be arranged. Each pump is to have at least two thirds the capacity of a bilge pump as determined by Pt 5 but not less than 25 m h . Each fire pump is to be able to deliver sufficient quantity and pressure of water to simultaneously operate the hydrants as required by (4) below. 【See Guidance】

(2) The arrangement of the pumps is to be such that in the event of a fire in any one compart- ment all the fire pumps will not be put out of action. 【See Guidance】

(3) Isolating valves to separate the section of the fire main within the machinery space containing

the main fire pump or pumps from the rest of the fire main are to be fitted in an easily acces- sible and tenable position outside the machinery spaces. The fire main is to be so arranged that when the isolating valves are shut all the hydrants on the craft, except those in the machinery space referred to above, can be supplied with water by a fire pump not located in this machi- nery space through pipes which do not enter this space. The spindles of manually operated

valves are to be easily accessible and all valves are to be clearly marked. 【See Guidance】

(4) Hydrants shall be so arranged so that any location on the craft can be reached by the water jets from two fire hoses from two different hydrants, one of the jets being from a single length of hose. Ro-ro spaces hydrants are to be located so that any location within the space can be reached by two water jets from two different hydrants, each jet being supplied from a single length of hose.

(5) Each fire hose is to be of non-perishable material and have a maximum length approved by the Administration, Fire hoses, together with any necessary fittings and tools, are to be kept ready for use in conspicuous positions near the hydrants. All fire hoses in interior locations are to be connected to the hydrants at all times. One fire hose is to be provided for each hydrant as re- quired by (4) above.

(6) Each fire hose is to be provided with a nozzle of an approved dual purpose type (i.e. spray/jet type) incorporating a shutoff.

(7) Where deep-fat cooking equipment is installed, all such installations are to be fitted with:

(A) an automatic or manual fixed extinguishing system tested to able to the Society.

(B) a primary and back up thermostat with an alarm to alert the

an appropriate standard accept- operator in the event of failure

of either thermostat.

(C) arrangements for automatically shutting off the electrical power to the deep-fat cooking equipment upon activation of the extinguishing system.

(D) an alarm for indicating operation of the extinguishing system in the galley where the equip- ment is installed.

(E) controls for manual operation of the extinguishing system which are clearly labelled for

ready use by the crew.

202. Protection of special category and ro-ro spaces

1. Fixed fire-extinguishing system

Each special category space and ro-ro spaces are to be fitted with an approved fixed pressure wa- terspraying system for manual operation which is to protect all parts of any deck and vehicle plat- form in such space, provided that the Society may permit the use of any other fixed fire-ex- tinguishing system that has been shown by full-scale test in conditions simulating a flowing petrol fire in the space to be not less effective in controlling fires likely to occur in such a space.

2. Patrols and detection

(1) A continuous fire patrol is to be maintained in special category spaces and ro-ro spaces unless a fixed fire detection and fire alarm system, complying with the requirements of 201. 2, and a television surveillance system are provided. The fixed fire detection system is to be capable of rapidly detecting the onset of fire. The spacing and location of detectors are to be tested taking

into account the effects of ventilation and other relevant factors. 【See Guidance】

(2) Manually operated call points are to be provided as necessary throughout the special category spaces and ro-ro spaces and one is to be placed close to each exit from such spaces. Manually

operated call points are to be spaced so that no part of the space is to be more than 20 m

from a manually operated call point.

3. Fire-extinguishing equipment

There is to be provided in each special category space and ro-ro space.

(A) At least three water fog applicators,

(B)

(C)

One portable foam applicator unit consisting of an air-foam nozzle of an inductor type capable of being connected to the fire main by a fire hose, together with a portable tank containing 20

of foam-making liquid and one spare tank. The nozzle is to be capable of producing

effec-

tive foam suitable for extinguishing an oil fire of at least 1.5 m mi n . At least two portable foam applicator units are to be available in the craft for use in such space, and Portable fire extinguishers of approved type and design are to be located so that no point in the space is more than approximately 15 m walking distance from an extinguisher, provided

4. Ventilation system

(1) There is to be provided an effective power ventilation system for the special category spaces and ro-ro spaces sufficient to give at least 10 air changes per hour while navigating and 20 air changes per hour at the quayside during vehicle loading and unloading operations. The system for such spaces is to be entirely separated from other ventilation systems and is to be operating at all times when vehicles are in such spaces. Ventilation ducts serving special category spaces and ro-ro spaces capable of being effectively sealed are to be separated for each such space. The system is to be capable of being controlled from a position outside such spaces.

(2) The ventilation is to be such as to prevent air stratification and the formation of air pockets.

(3) Means are to be provided to indicate in the operating compartment any loss or reduction of the required ventilating capacity.

(4) Arrangements are to be provided to permit a rapid shutdown and effective closure of the ven-

tilation system in case of fire, taking into account the weather and sea conditions.

(5) Ventilation ducts, including dampers, are to be made of steel or other equivalent material. Ducts lying inside the served space may be made of non-combustible or fire-restricting material.

5. Scuppers, bilge pumping and drainage

In view of the serious loss of stability which could arise due to large quantities of water accumu- lating on the deck or decks consequent to the operation of the fixed pressure water-spraying sys-

tem, scuppers are to be fitted so as to ensure that such water is rapidly discharged directly overboard. Alternatively, pumping and drainage facilities are to be provided additional to the re- quirements of Pt 5. When it is required to maintain watertight or weathertight integrity, as appro- priate, the scuppers are to be arranged so that they can be operated from outside the space protected.

6. Precautions against ignition of flammable vapours

(1) On any deck or platform, if fitted, on which vehicles are carried and on which explosive va- pours might be expected to accumulate, except platforms with openings of sufficient size permit- ting penetration of petrol gases downwards, equipment which may constitute a source of ignition of flammable vapours and, in particular, electrical equipment and wiring, are to be installed at least 450 mm above the deck or platform. Electrical equipment installed at more than 450 mm above the deck or platform is to be of a type so enclosed and protected as to prevent the es- cape of sparks. However, if the installation of electrical equipment and wiring at less than 450 mm above the deck or platform is necessary for the safe operation of the craft, such electrical equipment and wiring may be installed provided that it is of a type approved for use in an ex- plosive petrol and air mixture.

(2) Electrical equipment and wiring, if installed in an exhaust ventilation duct, are to be of a type approved for use in explosive petrol and air mixtures and the outlet from any exhaust duct is

to be sited in a safe position, having regard to other possible sources of ignition.

203. Fire control plans

1. There are to be permanently exhibited, for the guidance of the master and officers of the craft, fire control plans showing clearly for each deck the following positions.

The control stations, the sections of the craft which are enclosed by fire-resisting divisions together with particulars of the fire alarms, fire detection systems, the sprinkler installations, the fixed and portable fire-extinguishing appliances, the means of access to the various compartments and decks in the craft, the ventilating system including particulars of the master fan controls, the positions of dampers and identification numbers of the ventilating fans serving each section of the craft, the lo- cation of the international shore connection, if fitted, and the position of all means of control re- ferred to in Ch 1, 206. 3 and 207. 2. and Ch 2, 201. 1 and 4.

The text of such plans is to be in the official language of the flag State. However, if the language is neither English nor French, a translation into one of those languages is to be included.

【See Guidance】

2. A duplicate set of fire control plans or a booklet containing such plans is to be permanently stored in a prominently marked weathertight enclosure outside the deckhouse for the assistance of shore side fire-fighting personnel.

204. Fire-fighter's outfits 【See Guidance】

1. All craft, other than category A passenger craft, are to carry at least two fire-fighter‘s outfits com- plying with the requirements of Par 3. 【See Guidance】

(1) In addition, there are to be provided in category B passenger craft for every 80 m , or part

thereof, of the aggregate of the length of all passenger spaces and service

spaces on the deck

which carries such spaces; or, if there is more than one such deck, on the deck which has the largest aggregate of such length, two fire-fighter's outfits and two sets of personal equipment, each set comprising the items stipulated in 3. (1), (A) to (C);

(2) In category B passenger craft, for each pair of breathing apparatus there is water fog applicator which is to be stored adjacent to such apparatus.

to be provided one

(3) Additional sets of personal equipment and breathing apparatus, having due regard to the size and type of the craft, may be required.

2. The fire-fighter's outfits, or sets of personal equipment, are to be so stored as to be easily acces- sible and ready for use and, where more than one fire-fighter's outfit or more than one set of per- sonal equipment is carried, they are to be stored in widely separated positions.

3. A fire-fighter's outfit is to consist of:

(1) Personal equipment comprising:

(A) Protective clothing of material to protect the skin from the heat radiating from the fire and from burns and scalding by steam or gases. The outer surface is to be water-resistant,

(B) Boots and gloves of rubber or other electrically non-conductive material,

(C) A rigid helmet providing effective protection against impact,

(D) An electric safety lamp (hand lantern) of an approved type with a minimum burning period of 3 hours, and

(E) An axe.

(2) A breathing apparatus of an approved type which may be either:

(A) A smoke helmet or smoke mask which is to be provided with a suitable air pump and a length of air hose sufficient to reach from the open deck, well clear of hatch or doorway, to any part of the holds or machinery spaces. If, in order to comply with this subparagraph, an air hose exceeding 36 m in length would be necessary, a self-contained breathing appara- tus is to be substituted or provided in addition, or

(B) A self-contained compressed-air-operated breathing apparatus, the volume of air contained in

the cylinders of which is to be at least 1,200 , or other self-contained breathing apparatus which is to be capable of functioning for at least 30 minutes. A number of spare charges,

suitable for use with the apparatus provided, are to be available on board.

(3) For each breathing apparatus, a fireproof lifeline of sufficient length and strength is to be pro- vided capable of being attached by means of a snap hook to the harness of the apparatus or to a separate belt in order to prevent the breathing apparatus becoming detached when the lifeline

205. Fuel and other flammable fluid tanks and systems

1. A fixed vapour detection system is to be installed in each space through which fuel lines pass, with alarms provided at the continuously manned control station.

2. Every fuel tank is, where necessary, to be provided with "savealls" or gutters which would catch any fuel which may leak from such tanks.

3. Safe and efficient means of ascertaining the amount of fuel contained in any tank are to be provided. Sounding pipes are not to terminate in any space where the risk of ignition of spillage from the sounding pipe might arise. In particular, they are not to terminate in passenger or crew

spaces. The use of cylindrical gauge glasses is prohibited, except for cargo

craft where the use of

oil-level gauges with flat glasses and

self-closing valves between the gauges

and fuel tanks may be

permitted. Other means of ascertaining the amount of fuel contained in any

tank may be permitted

if such means do not require penetration below the top of the tank, and providing their failure or overfilling of the tank will not permit the release of fuel.

4. During bunkering operations no passenger is to be on board the craft or in the vicinity of the bun- kering station. Adequate 'No Smoking' and 'No Naked Lights' signs are to be posted. Vessel-to- shore fuel connections are to be of closed type and suitably grounded during bunkering operations.

The provision of fire detection and extinguishing systems in spaces where non-integral fuel tanks

5. are located is to be in accordance with paragraphs 201. 1 to 4.

Refuelling of the craft is to be done at the approved refuelling facilities, detailed in the route op-

6. erational manual, at which the following fire appliances are provided:

(1) A suitable foam applicator system consisting of monitors and foam-making branch pipes capable of delivering foam solution at a rate of not less than 500 l mi n for not less than 10 min.

(2) Dry powder extinguishers of total capacity not less than 50 kg.

(3) Carbon dioxide extinguishers of total capacity not less than 16 kg.