Start hereRules checked 20 October 2026
A portable extinguisher is the first thing a crew member reaches for, and the first minute decides whether a small fire stays small. The wrong agent can make things worse. Water on a fat fryer fire throws burning oil across the galley. CO2 released in a cabin can leave the person who fired it short of oxygen. Powder on a switchboard leaves a residue that can damage electrical contacts.
The rules on board are built around that problem. They specify which agents to carry, the minimum size of each extinguisher, and where each one must hang so that the right type is near every hazard. This lesson covers the types, the fire classes and the placement rules, starting with a sorting exercise.
Try it
Match the fire to its class
In plain words
A fire needs fuel, heat and oxygen. An extinguisher works by taking one of them away. Water cools. Foam smothers a liquid surface and cools solids. CO2 pushes the oxygen out of a small area. Powder breaks the chemical reaction of the flame. Wet chemical forms a soapy crust on hot cooking oil and cools it.
Fires are grouped into classes by what is burning, and every extinguisher label shows the classes it is approved for:
- A: solids such as wood, paper, cloth and many plastics.
- B: liquids, and solids that melt into liquids: fuel, lube oil, paint.
- C: gases under the ISO and European system. Under the American NFPA system, C means live electrical equipment. This matters on ships, because IMO documents use both.
- D: burning metals such as magnesium or lithium metal. These need special powders.
- F (ISO) or K (NFPA): cooking oils and fats.
The rules then make sure the right type is in the right place: never CO2 in cabins, a non-conductive agent near switchboards, a class F or K unit where there is a deep fat fryer, and an extinguisher near the entrance to every space.
In detail
The agents and what they are recommended for
Resolution A.951(23) section 3 classifies marine portable extinguishers by agent1:
| Agent | Recommended for | Watch out for |
|---|---|---|
| Water, or water with additives | Wood, paper, textiles | Not where there is an electrical hazard. Plain water charges can freeze. |
| Foam | Wood, paper, textiles and flammable liquids | The fire is only out when the whole burning surface is covered |
| Dry powder, standard (B, C) | Flammable liquids, electrical equipment, flammable gases | Blown off target in the open or in ventilated spaces. Impairs vision. Can damage electrical contacts. Some powders are affected by humidity. |
| Dry powder, multi-purpose (A, B, C) | All of the above plus solids | As above |
| Dry powder, metal (D) | Combustible metals | Use only the powder approved for that metal |
| Carbon dioxide | Flammable liquids and electrical equipment | Can suffocate in small spaces. Little effect in wind or in ventilated spaces. |
| Wet chemical (F or K) | Cooking grease, fats and oils | Galley use |
A.951(23) paragraph 7.2 adds two principles. Choose size and type for the actual hazard “while avoiding a multiplicity of types”, and make sure the amount of agent released in a small space does not endanger the people in it.1
Fire classes: ISO against NFPA
A.951(23) paragraph 5.1 sets the two systems side by side.1 ISO 3941 (which the European EN 2 follows closely) uses A solids, B liquids, C gases, D metals, F cooking oils. NFPA 10 uses A ordinary combustibles, B flammable liquids and gases, C energised electrical equipment, D metals, K cooking oils.
The table in MSC.1/Circ.1275 marks the space next to main switchboards as “C” and galleys with deep fat fryers as “F or K”. The circular says the classes in its table “are only for reference” and that the choice should follow A.951(23).4 In practice, read the class on the label together with the agent. A CO2 or suitable powder unit near a switchboard is right whichever system the label uses.
Minimum size and approval
The FSS Code chapter 4 requires every extinguisher to be of an approved type (paragraph 2). Paragraph 3.1.1.1 requires at least 5 kg for each powder or CO2 extinguisher and at least 9 l for each foam extinguisher. No portable extinguisher may weigh more than 23 kg, and each must be at least as effective as a 9 l fluid extinguisher.2 A.951(23) paragraph 7.1 explains that equivalence as a 9 l water or foam extinguisher with a 2A rating on class A fire.1 Only refills approved for that extinguisher may be used (FSS Code chapter 4, paragraph 3.1.2).2
Markings to check
A.951(23) paragraph 8.1 lists what every extinguisher should show: manufacturer; fire types and rating; type and quantity of agent; approval details; instructions for use and recharge, preferably with pictures; year of manufacture; operating temperature range; and test pressure.1 Extinguishers must also show whether they have been used, through a seal, pin or other indicator (SOLAS regulation II-2/10.3.2.4).3
Where they go: the SOLAS rules
SOLAS regulation II-2/10.3.2 sets the principles3:
- Accommodation spaces, service spaces and control stations get extinguishers of suitable types and numbers. Ships of 1,000 gross tonnage and upwards carry at least five.
- One extinguisher for each space is stowed near the entrance to that space.
- CO2 extinguishers are not placed in accommodation spaces. In control stations and spaces with electrical or electronic equipment needed for the ship’s safety, the agent must be neither electrically conductive nor harmful to the equipment.
- They must be in easily visible places, reachable quickly, and protected from weather and vibration.
Machinery spaces have their own rules in regulation II-2/10.5.3 In machinery spaces of category A with internal combustion machinery, the ship carries foam-type extinguishers of at least 45 l (or equivalent) that can reach the fuel and lubricating oil pressure systems. It also needs enough portable foam extinguisher or equivalent so that no point is more than 10 m walking distance from one, with at least two in each such space. Boiler rooms need at least one 135 l foam-type extinguisher with hoses on reels. Domestic boilers under 175 kW have been exempt since the 2000 text; since resolution MSC.409(97) (in force 1 January 2020, and applied to existing ships too) boilers protected by fixed water-based local application systems are also exempt (regulation II-2/10.5.1.2.2).35
The unified interpretation: MSC.1/Circ.1275
“Of appropriate types and in sufficient number to the satisfaction of the Administration” leaves a lot open. MSC.1/Circ.1275 gives the numbers for ships built on or after 1 January 2009, and encourages owners of older ships to use it.4 Extracts from its table:
| Space | Minimum | Class |
|---|---|---|
| Public spaces | 1 per 250 m² of deck area or part of it | A |
| Corridors | Travel distance to an extinguisher not more than 25 m on each deck and in each main vertical zone | A |
| Hospital | 1 | A |
| Galleys | 1 class B, plus 1 class F or K where there are deep fat fryers | B, F or K |
| Wheelhouse | 2 (1 if the wheelhouse is under 50 m²) | A or C |
| Near main switchboards | 2 | C |
| Machinery space workshops | 1 | A or B |
| Periodically unattended machinery spaces of category A | 1 at each entrance | B |
| Cargo pump-room | 2 | B |
| Ro-ro and vehicle spaces | Not more than 20 m apart on both sides of the space at each deck level (as corrected by Corr.1, 2017) | B |
Notes to the table add that a small space’s extinguisher may be placed outside near its entrance. Two dry powder extinguishers of at least 6 kg each (or equivalent) should be carried when dangerous goods are on the weather deck or in open ro-ro and vehicle spaces.4
PFOS and foam charges
Since 1 January 2026, SOLAS regulation II-2/10.11.2.2 has banned the use or storage of extinguishing media containing PFOS. Existing ships must comply by their first survey on or after that date (regulation II-2/1.2.10). PFOS media removed from a ship go to shore reception facilities (10.11.2.1).6 Check the safety data sheet or supplier declaration of every foam charge, including those in spare charge stock.
What the rules say
- FSS Code chapter 4, paragraph 3.1.1.1, requires at least 5 kg for each powder or CO2 extinguisher and at least 9 l for each foam extinguisher, and a maximum mass of 23 kg for any portable extinguisher.2
- FSS Code chapter 4, paragraph 3.1.2, says “only refills approved for the fire extinguisher in question shall be used for recharging”.2
- SOLAS regulation II-2/10.3.2.1 requires ships of 1,000 gross tonnage and upwards to carry at least five portable fire extinguishers in accommodation, service spaces and control stations.3
- SOLAS regulation II-2/10.3.2.2 requires one of the extinguishers intended for any space to be stowed near the entrance to that space.3
- SOLAS regulation II-2/10.3.2.3 forbids CO2 extinguishers in accommodation spaces, and requires non-conductive, equipment-safe agents in control stations and safety-critical electrical spaces.3
- SOLAS regulation II-2/10.5.2.2 requires portable foam extinguishers or equivalent so that no point in a category A machinery space with internal combustion machinery is more than 10 m walking distance from one, with at least two in each space.3
- MSC.1/Circ.1275 section 2 gives the minimum number and distribution of portable extinguishers by type of space, for ships built on or after 1 January 2009.4
- Resolution A.951(23) paragraph 7.2 says size and type should match the hazards “while avoiding a multiplicity of types”, without endangering people in small spaces.1
Flag and class notes
- The Marshall Islands requires ships built on or after 1 January 2009 to use the MSC.1/Circ.1275 table, as corrected by Corr.1, as the reference for number and arrangement, and allows it for older ships. Liberia says such ships should follow MSC.1/Circ.1275 and encourages it for older ships.78
- Class and flag surveyors check the extinguishers against the ship’s fire control plan, which shows the fire-extinguishing appliances (SOLAS regulation II-2/15.2.4).3 When you change a type or location, update the plan and tell your class society.
- How to check: some flags set their own equivalents for “to the satisfaction of the Administration” (FSS Code chapter 4, paragraph 3.1.1.2, leaves the equivalents of extinguishers to the Administration).2 Ask the flag or your recognised organisation whether it accepts, for example, a 6 kg powder unit in place of a 9 l foam unit.
Key numbers
| What | Value |
|---|---|
| Minimum charge, powder or CO2 | 5 kg2 |
| Minimum charge, foam | 9 l2 |
| Maximum mass of a portable extinguisher | 23 kg2 |
| Minimum number, ships of 1,000 GT and upwards | 5 (accommodation, service spaces, control stations)3 |
| Walking distance in category A machinery spaces | Not more than 10 m, at least 2 per space3 |
| Foam extinguishers for machinery fire hazards | At least 45 l each, or equivalent3 |
| Boiler room foam extinguisher | At least 135 l, on a hose reel3 |
| Public spaces (MSC.1/Circ.1275) | 1 per 250 m² of deck area4 |
| Corridors (MSC.1/Circ.1275) | Not more than 25 m travel to an extinguisher4 |
| Dangerous goods on deck (MSC.1/Circ.1275) | 2 dry powder extinguishers of at least 6 kg each4 |
What inspectors find
- Fire-fighting equipment deficiencies are common. Tokyo MOU inspectors recorded 392 deficiencies under “fire fighting equipment and appliances” in three months of the 2023 fire safety campaign.9
- CO2 in the wrong place. A CO2 extinguisher in a mess room, cabin corridor or office breaches SOLAS regulation II-2/10.3.2.3. This is easy to spot and easy to avoid.3
- No extinguisher at the entrance. Units kept deep inside a store or workshop, or none near the door, breach regulation II-2/10.3.2.2.3
- Galleys without a class F or K unit where there is a deep fat fryer, against the MSC.1/Circ.1275 table.4
- Extinguishers that do not match the fire control plan in number, type or position. Surveyors compare the plan with what is on the bulkhead.3
FAQ
Can we replace all our foam extinguishers with powder to simplify spare charges?
Possibly in some spaces, but check the space rules first. Category A machinery spaces call for foam or equivalent (SOLAS regulation II-2/10.5). The FSS Code leaves equivalents to the Administration, so ask your flag or recognised organisation. A.951(23) supports fewer types, but every hazard must still be covered.
Is a 2 kg CO2 extinguisher acceptable in the wheelhouse?
Not as one of the required extinguishers. The FSS Code requires at least 5 kg for CO2 and powder, and at least the capability of a 9 l fluid extinguisher. Smaller units can be extra, but they do not count towards the required number.
Why is "class C" confusing on ships?
Under ISO 3941 and EN 2, class C is gas fires. Under NFPA 10, class C is live electrical equipment. A.951(23) shows both systems, and MSC.1/Circ.1275 uses C for spaces with switchboards. Read the agent and the pictograms on the label, not just the letter.
Quiz7 questions
Sources
- 1
IMO Resolution A.951(23), Improved guidelines for marine portable fire extinguishers, adopted 5 December 2003, annex sections 2, 3, 5, 7 and 8 and the appendix table. https://wwwcdn.imo.org/localresources/en/KnowledgeCentre/IndexofIMOResolutions/AssemblyDocuments/A.951(23).pdf
- 2
IMO Resolution MSC.98(73), International Code for Fire Safety Systems (FSS Code), adopted 5 December 2000, chapter 4, paragraphs 2, 3.1.1 and 3.1.2. https://wwwcdn.imo.org/localresources/en/KnowledgeCentre/IndexofIMOResolutions/MSCResolutions/MSC.98(73).pdf
- 3
IMO Resolution MSC.99(73), revised SOLAS chapter II-2, adopted 5 December 2000, regulations II-2/10.3, 10.5 (including 10.5.1.2.2) and 15.2.4. https://wwwcdn.imo.org/localresources/en/KnowledgeCentre/IndexofIMOResolutions/MSCResolutions/MSC.99(73).pdf
- 4
IMO MSC.1/Circ.1275, Unified interpretation of SOLAS chapter II-2 on the number and arrangement of portable fire extinguishers on board ships, 3 June 2008, annex sections 1 to 3 and table (copy published by Traficom, Finland); and MSC.1/Circ.1275/Corr.1, 31 March 2017 (copy published by the German flag administration, https://deutsche-flagge.de/de/redaktion/dokumente/interpretationen/solas/ii-2/msc-1-circ-1275-corr-1-unified-interpretation-of-solas-chapter-ii-2-on-the-number-and-arrangement-of-portable-fire-extinguishers-on-board-ships.pdf). https://www.traficom.fi/files/media/regulation/22668-MSC_1-Circ_1275_-_Tulkinta_SOLAS_II-2.pdf
- 5
IMO Resolution MSC.409(97), Amendments to SOLAS 1974, adopted 25 November 2016, annex item 3 (regulation II-2/10.5.1.2.2). https://wwwcdn.imo.org/localresources/en/KnowledgeCentre/IndexofIMOResolutions/MSCResolutions/MSC.409(97).pdf
- 6
IMO Resolution MSC.532(107), 2023 amendments to SOLAS 1974, adopted 8 June 2023, in force 1 January 2026, regulations II-2/1.2.10 and 10.11. https://wwwcdn.imo.org/localresources/en/KnowledgeCentre/IndexofIMOResolutions/MSCResolutions/MSC.532(107).pdf
- 7
Liberia Maritime Authority, Marine Notice FIR-001 Rev. 02/26, Fire-protection systems and appliances, section 6.4. https://www.liscr.com/sites/default/files/online_library/FIR-001.pdf
- 8
Republic of the Marshall Islands Maritime Administrator, Marine Notice 2-011-14 Rev. Aug/2025, section 8.3. https://www.register-iri.com/wp-content/uploads/MN-2-011-14.pdf
- 9
Tokyo MOU, Report of the 2023 Concentrated Inspection Campaign (CIC) on Fire Safety, table 3. https://www.tokyo-mou.org/wp/wp-content/uploads/CIC-ON-FIRE-SAFETY-2023-Report-public.pdf
Rules checked 20 October 2026. VSL Safety is not an approved training provider and doesn't issue certificates. These lessons don't replace STCW training, or the manufacturer's training and certification that service technicians need.
