Fire Prevention, Detection and Fixed Fire-Fighting Systems

Fire prevention: housekeeping and good habits

In short: Read first: the fire triangle and portable extinguishers and the ship’s emergency organisation. Fire safety at sea works in layers: prevent the fire, detect it fast, contain and extinguish it, and give people a safe way out (IMO, SOLAS chapter II-2). Prevention is the cheapest layer: most fires start from poor housekeeping.

• Good housekeeping: keep every space clean and tidy. Rubbish, rags and packaging are fuel waiting for heat.
• Laundries: tumble dryers collect lint, which burns easily. Clean the filters, and do not leave dryers running unattended.
• Wastepaper baskets: use non-combustible (metal) baskets and never empty ashtrays into them.
• Rubbish: control it. Collect it in closed containers and land it ashore regularly; never let it pile up in passageways or stores.
• Galley exhaust: grease builds up in hoods, filters and ducts and can carry a fire right through the ship. Clean them often. On SOLAS ships the galley duct has a grease trap, a fire damper and fans that can be stopped from the galley (SOLAS II-2/9.7.5).
• Combustibles near heat: keep them away from heaters, lamps, exhausts and hot pipes.
• No clothes hung to dry over cookers or heaters.
• Oily waste: oily rags can heat up by themselves (spontaneous combustion). Put them in steel bins with lids and empty the bins often. Keep the machinery space clean and clear of oily waste (Workboat Code Ed. 2, 14.4.5), and contain oil leaks with drip trays (14.4.1–14.4.3).
• Highly flammable materials (paint, thinners, solvents): at the end of the working day put them back in their designated store, such as the paint locker.
• Power points: do not overload them. Chains of adaptors overheat and start fires.

Galley and cookers on small vessels

• Materials near an open-flame cooker or heater are non-combustible, or faced with a finish rated Class 1 for surface spread of flame (MGN 280 (M), 14.5.3; Workboat Code Ed. 2, 14.5.3).
• Unprotected combustible surfaces are kept at least 400 mm above the cooker (horizontal surfaces) and 125 mm to the side (vertical surfaces) (MGN 280 (M), 14.5.4; Workboat Code Ed. 2, 14.5.4).
• Curtains and other hanging fabrics: not within 600 mm of any open-flame appliance (14.5.5 in both codes). A common short version groups curtains with the 400 mm / 125 mm rule; the codes give curtains their own, larger 600 mm distance.
• Where open-flame cooking or heating is in or next to the accommodation, fit carbon monoxide (CO) detectors (Workboat Code Ed. 2, 14.5.7).
• A fire blanket is kept in the galley or cooking area (Workboat Code Ed. 2, 15.4.4 and 15.5.3).

Containing a fire: boundaries, shutters and shut-offs

In short: If a fire starts, keep it in one space. The engine room must be a closed space that holds the extinguishing medium in, with ventilation and fuel that can be shut off from outside.

• Closed engine space: its boundary, with special care for the fire flaps, must be able to close down so the extinguishing medium cannot escape (Workboat Code Ed. 2, 14.1.1). With no proper machinery space, the engine sits in a box that does the same job (14.1.2).
• Ventilation can be stopped: fans in or feeding the machinery space, and fuel and oil transfer pumps and centrifuges, can be stopped from outside the space. Automatic fan stops need a manual override (14.1.1).
• Fire shutters (flaps, dampers) close the vents so the fire is starved of air and the gas stays in.
• Fuel remote shut-offs: quick-closing valves on the fuel tanks, closed from outside the space, cut the fuel to the fire (SOLAS II-2/4.2.2.3.4). Their remote linkages must not fail in a fire (Workboat Code Ed. 2, 14.1.5).
• Engine space rules: no combustible stores inside (14.1.3); no windows in its boundary except an observation port of at most 150 mm with A-0 fire-rated glass (14.1.4).
• FRP boundaries must stop smoke and flame for 15 minutes on vessels in area categories 0 and 1, over 750 kW per machinery space, or carrying 16 or more persons (Workboat Code Ed. 2, 14.2 and 14.2.3.1).
• Fireproof furniture: combustion-modified high-resilience (CMHR) foam in upholstery and mattresses, and covering fabrics that pass the cigarette and butane flame tests (MGN 280 (M), 14.6).
• Large ships: steel A-class divisions stop smoke and flame for 60 minutes in the standard fire test; the insulation rating (A-60, A-30, A-15, A-0) is the number of minutes the unexposed side stays below the temperature limit. B-class divisions work for 30 minutes (SOLAS II-2/3). Fire doors and dampers keep the fire inside its zone.

Fire detection and alarms

In short: A fire found in the first minutes is a small fire. Ships use smoke, heat and flame detectors plus manual call points, wired to a fire alarm panel on the bridge or in the control station (SOLAS II-2/7; FSS Code ch. 9).

• Smoke detectors: the first choice in cabins, corridors, stairways and escape routes, where a fire usually smoulders first.
• Heat detectors: galleys, laundries and other places where steam or fumes would set off a smoke detector. They react to a fixed temperature or to a fast rise.
• Flame detectors (UV or IR): machinery spaces, near boilers, purifiers and fuel pumps, where an oil fire flares up fast.
• Manual call points: anyone who sees a fire can raise the alarm at once.
• Periodically unattended machinery spaces must have a fixed fire detection and alarm system (SOLAS II-2/7).
• Small vessels (MGN 280 (M), 14.7): over 750 kW installed power → detectors in the engine space; 16 or more persons, or area category 0 or 1 → detectors in the engine space and in spaces with open-flame devices; any other fire-risk area (e.g. galley, sleeping cabins) → detectors where the Certifying Authority asks. Detectors must be heard in the space and at the control position.
• Alarm: on a small vessel the general or fire alarm can be a bell, klaxon, whistle or siren, if it is heard in all parts of the vessel (MGN 280 (M), 13.9).

Means of escape

In short: Every space where people sleep or a fire is likely needs two ways out, placed so that one fire cannot block both (MGN 280 (M), 14.8; SOLAS II-2/13).

• Two means of escape from: sleeping and rest spaces; other accommodation with a fire risk; machinery spaces with a fire risk (MGN 280 (M), 14.8.1).
• Machinery space exceptions: spaces visited only now and then, where the single access gives ready escape; or spaces where nobody is ever more than 5 m from the single entrance (14.8.1.3).
• Where a single escape from accommodation is accepted as an exception, fit fire detectors to give early warning (14.8.2).
• Escape routes are marked on both sides and tested in practice for the Certifying Authority (14.8.3).
• Sailing multihulls over 12 m: an escape hatch in each main inhabited compartment, above both the upright and the inverted waterline (14.8.4).
• Keep escape routes clear: a locked or cluttered escape is a fire-safety failure.

Fire pumps and the fire main

In short: The fire main is the ship’s water pipe for fire-fighting. Fire pumps keep it at pressure so that hoses at the hydrants can reach any part of the ship. A separate emergency fire pump takes over if a fire knocks out the main pumps.

• Power: fire pumps must not depend on the main engines. Sanitary, ballast, bilge or general service pumps may serve as fire pumps if they are not normally used for oil (MSN 1665 (M) Amdt 1, Schedule 7, 7.1).
• Number: passenger ships of 4,000 GT and over have at least three power-driven pumps; other passenger ships and cargo ships of 1,000 GT and over at least two (SOLAS II-2/10.2.2).
• Minimum pressure at the hydrants, cargo ships (MSN 1665 (M) Amdt 1, 7.9.3; SOLAS II-2/10.2.1.6):

• Passenger ships: 0.4 N/mm² at 4,000 GT and over, 0.3 N/mm² below that (SOLAS II-2/10.2.1.6; MSN 1665 (M) Amdt 1, 7.9.2).
• Relief valves stop the pumps over-pressurising the hoses; every centrifugal fire pump has a non-return valve (MSN 1665 (M) Amdt 1, 7.5–7.6).
• Isolating valve: outside the machinery space, so the rest of the fire main can still be fed by a pump outside that space if the engine room is on fire (7.10.9).
• Emergency fire pump: needed where a fire in one compartment could put all the main pumps out of action (SOLAS II-2/10.2.2). On UK ships it gives at least 40% of the main pumps’ capacity and never less than 25 m³/h; its diesel must start by hand from cold down to 0 °C; its fuel tank holds 3 hours at full load, with fuel for another 15 hours outside the main machinery space (MSN 1665 (M) Amdt 1, 7.8.1–7.8.4).
• Small vessels: see the 15 m checklist below — one power-driven self-priming pump, or alternatives.

Hydrants, hoses and nozzles

In short: Hydrants are placed so that at least two jets of water, not from the same hydrant, can reach any part of the ship, one of them from a single length of hose (SOLAS II-2/10.2.1.5.1). Nozzles are dual-purpose (jet and spray) with a shut-off.

• Hose length: at least 10 m; at most 15 m in machinery spaces, 20 m in other spaces and open decks, 25 m on open decks of ships wider than 30 m (SOLAS II-2/10.2.3.1.1).
• Number of hoses, ships of 1,000 GT and over: one for each 30 m of ship length plus one spare, never fewer than five (SOLAS II-2/10.2.3.2.1).
• Nozzle sizes: 12, 16 and 19 mm (or as near as possible) (SOLAS II-2/10.2.3.3). Small vessels: one hose with a 10 mm nozzle and a suitable spray nozzle (Workboat Code Ed. 2, 15.5.1.1).
• Jet reaches far and hits hard (class A fires); spray cools, protects the hose team like a shield and is safer near oil.
• Couplings: fully interchangeable on board unless each hydrant has its own hose and nozzle (MSN 1665 (M) Amdt 1, 7.10.5).
• Hydrant valves let you isolate and remove a hose while the pumps run (7.10.6). Pipes and hydrants are arranged so they cannot freeze (7.10.8).
• On board: keep each hose dry, rolled and stowed next to its hydrant with the nozzle attached, so one person can run it out fast.

The international shore connection (ISC)

In short: A standard flange that lets a shore fire brigade or another ship pump water into your fire main (or you into theirs), whatever hose couplings each side uses. Ships of 500 GT and over carry at least one, usable on either side of the ship (SOLAS II-2/10.2.1.7).

• One side is a flat-faced flange; the other has a coupling that fits your own hydrants and hoses (MSN 1665 (M) Amdt 1, 1.2).
• It is kept on board with its gasket, bolts and washers, ready to use, usually in a marked box near the gangway (1.2).
• When it is used: in port, when your fire pumps have failed or cannot cope, so the shore brigade can feed your fire main; or to help another ship.

Fixed fire-fighting systems: the types

In short: A fixed system puts out a fire in a whole space, usually the machinery space, without anyone going in (Workboat Code Ed. 2, 15.6.1.1), and is operated remotely from outside. The approved types are foam (medium or high expansion), CO2, pressure water spraying, vaporising fluids and aerosols (Workboat Code Ed. 2, 15.6.3.3), plus water mist (“high fog”).

Foam

• Medium and high expansion foam fill a whole machinery space with light foam; low expansion foam (a dense blanket) is also listed for small vessels (MGN 280 (M), 15.6.2) and is used on decks and oil pools.
• A portable foam applicator makes foam no more than 12 times the volume of the solution (MSN 1665 (M) Amdt 1, Schedule 6, 6.3).

CO2

• The classic engine-room system on cargo ships and many yachts. It is the last resort: use it when the fire cannot be fought any other way. Its safety rules are in the next section.

Water: sprinklers, water spray and water mist

• Automatic sprinklers protect accommodation: a bulb bursts in the heat and that head sprays the fire. The system is kept under pressure by its own pump, so you check pump and system pressure regularly.
• Pressure water spraying covers machinery spaces with fixed nozzles.
• Water mist (high fog) uses far less water than sprinklers and is now common in engine rooms and on yachts, often as local protection over hot spots such as generators and purifiers.

Vaporising fluids and the halon ban

• Today’s vaporising fluids are hydrofluorocarbons (HFCs) (Workboat Code Ed. 2, 15.6.3.3).
• Halons destroy the ozone layer: their sale and use are prohibited, even recycled, and no fire-fighting equipment containing halon may be placed on board (EC Regulation 1059/2009; Workboat Code Ed. 2, 15.7.5; MGN 191 (M+F)).

Aerosols

• Condensed aerosols are made by burning a solid charge in a generator. They are allowed only in machinery spaces that are not normally occupied (MGN 657 (M+F) Amdt 2).
• An isolation switch outside the space is used whenever someone goes in; automatic release has a pre-discharge alarm of at least 20 seconds; all openings are closed before discharge (MGN 657 (M+F) Amdt 2, based on IMO MSC.1/Circ.1270).
• Warning notices cover the hot discharge and possible dangerous carbon monoxide.

Fixed CO2: safe operation

In short: Total flooding of an engine room needs about 35% CO2 by volume within 2 minutes. That brings oxygen below 15%: the fire goes out, and no one can survive in the space (MGN 354 (M+F), 2.3). So: everyone out, head count, space sealed, then release.

• The gas: colourless, slight sharp smell, makes you cough; acutely toxic at high concentration; about 50% heavier than air, so it blankets the fire (MGN 354 (M+F), 2.2).
• Alarm: opening the CO2 release cabinet door automatically sounds the audible and visual CO2 alarm in the machinery space (4.3). Everyone leaves as soon as it sounds.
• Never release until all people have left and a full head count is done (2.4).
• Before release: close and seal the ventilation flaps, use the fan emergency stops, and close all fuel and hydraulic oil quick-closing valves (2.5). Shut down the machinery in the space — main engines and generators — so nothing keeps feeding fuel or oil to the fire (2.6).
• Speed: the concentration becomes dangerous within about 15–20 seconds of release (2.10). Anyone caught inside: hold your breath and get out at once (2.11).
• Tell the Coastguard about any fire on board as soon as practicable, including one that needs the CO2 system (2.1).

After the release

• Check that the gas has really gone: the cylinders feel cold and their release valves are open (MGN 354 (M+F), 3.2).
• Keep well clear of the ventilation flaps — noxious gases (3.3).
• Do not ventilate until it is certain the fire is out — usually several hours. Monitor boundary temperatures; a little water on a boundary that turns to steam shows it is still hot (3.4).
• Get expert advice from ashore before ventilating or re-entering; the Coastguard can help find it (3.1).
• Re-entry only by trained people in breathing apparatus with lifelines and back-up ready (3.5). Smoke hoods and filter masks give no protection against CO2 or low oxygen (3.12–3.13).
• Instructions for the system are displayed by the remote controls, the valves and the cylinders; remote controls, valves and alarms are marked, tested and maintained (4.1–4.3).

Checklist: small vessels of 15 m and over

In short: UK small-vessel codes set out the fire kit by size. For vessels of 15 m or more, or carrying 16 or more persons, the main items are a power-driven fire pump, two multi-purpose extinguishers, a fire blanket and a way to flood the engine space without entering it (Workboat Code Ed. 2, 15.5–15.6). Smaller vessels: MGN 280 (M) and Workboat Code Ed. 2, chapters 14–15. Large yachts follow the REG Yacht Code.

• Fire pump: one power-driven self-priming fire pump able to send one jet of water to any part of the vessel, with sea and hose connections, one hose with a 10 mm nozzle and a spray nozzle. Fire main pressure must survive the loss of any one machinery space (Workboat Code Ed. 2, 15.5.1.1).
  • Or instead: one hand fire pump outside the machinery space (15.5.1.2).
  • Or, if the machinery space has under 120 kW and a diesel engine: at least two multi-purpose extinguishers (13A/113B each) outside each machinery space, on top of those below (15.5.1.3).
• Second pump: a common best-practice list adds an emergency (portable) fire pump that also reaches any part of the vessel. The Workboat Code asks for one pump; large ships need an emergency pump under SOLAS (see fire pumps above).
• Extinguishers: at least two multi-purpose extinguishers of 13A/113B (15.5.2), in a sufficient number for the vessel. Multi-purpose means they work on both class A solids and class B liquids (15.7.1).
• Engine space: fire extinguishing suitable for its volume; nobody should need to enter to fight the fire (15.6.1.1). This can be a portable extinguisher arranged to discharge into the space through a fire port (15.6.2.1), or, ideally, a fixed system operated remotely, of an MCA-approved type (15.6.3.1).
• Fire blanket in the galley (15.5.3) and two fire buckets with lanyards (MGN 280 (M), 15.5.3).
• Also on the list: smoke detectors, two escape routes, fireproof furniture, closed engine space with ventilation that can be shut, fire shutters and remote fuel shut-offs (see the sections above).

Testing and maintenance

In short: Fire equipment only works if it is tested. Ships follow a planned maintenance schedule built on IMO MSC.1/Circ.1432 (fire protection systems); fixed CO2 systems have their own guidelines, IMO MSC.1/Circ.1318/Rev.1. Fixed extinguishing systems are also exercised in fire drills.

• Portable extinguishers: a common rule of thumb is “serviced every year, pressure-tested every 5 years”. The official UK intervals are: basic service every year, extended service (test discharge) every 5 years, overhaul with hydraulic (pressure) test every 10 years (MGN 276 (M+F) Amdt 1, Table 1). All equipment is serviced at the maker’s intervals by an approved service station (MGN 280 (M), 15.1).
• Fire drills: run them as a real emergency, in a different part of the ship each time, and test the fixed extinguishing systems as part of them.