Fire class · UK/EU and US
Class A: solids such as wood, paper and cloth
First: raise the alarm, get out, call the fire service
UK: However, if in doubt, employees should not put themselves or anyone else at risk, but simply raise the alarm, leave the premises, and call the fire and rescue service.
HM Government (GOV.UK), A guide to making your small non-domestic premises safe from fire (accessible version), section ‘Fire extinguishers’
US: If you're unsure about whether it is safe to use a fire extinguisher, and for all other situations, alert others, leave the building, and call 911 from a mobile or neighbor's phone.
US Fire Administration (FEMA), Choosing and Using Fire Extinguishers, ‘Help people decide when to use a fire extinguisher’
Solids: wood, paper, textiles.
UK and Europe (BS EN 2 classes)
Fires involving solid materials such as wood, paper or textiles.
HM Government (GOV.UK), Fire safety risk assessment: offices and shops (accessible version), Part 2, 3.1, Table 1: Class of fireCLASS A: Fires involving solid materials usually of an organic nature in which combustion normally takes place with the formation of glowing embers, e.g. wood, paper or textiles.
London Fire Brigade (London Fire Commissioner), Fire Safety Guidance Note GN08: Hand Held Portable Firefighting Equipment, Rev 20, §3.2 (after BS EN 2)
United States (NFPA 10 classes)
Fires in ordinary combustible materials, such as wood, cloth, paper, rubber, and many plastics.
National Fire Protection Association (NFPA), Fire Extinguisher Ratings (NFPA Today blog, Brian O’Connor), table of classes
Extinguishers the guidance names for Class A
UK/EU
Extinguishers the guidance says not to use on it
- Carbon dioxide (CO2):
CO2 is not recommended for Class A fires because they may continue to smolder and re-ignite after the CO2 dissipates.
US Occupational Safety and Health Administration (OSHA), eTool: Evacuation Plans and Procedures, Portable Fire Extinguishers, Extinguisher Basics, Carbon dioxide extinguishers - Wet chemical:
Also keep in mind that if a Class K fire extinguisher is installed, there still needs to be extinguisher(s) available for any other combustible materials in the area since oftentimes a Class K extinguisher can’t be used on an ordinary combustibles fire, flammable liquids fire, electrical fire, or combustible metals fire.
National Fire Protection Association (NFPA), What Is a Class K Fire Extinguisher? (NFPA Today blog, Brian O’Connor), ‘Where should I install Class K fire extinguishers?’
Reading the letter
CLASS A: … Types include Water extinguisher, Foam Extinguisher, Dry Powder extinguisher (size according to risk).
London Fire Brigade (London Fire Commissioner), Fire Safety Guidance Note GN08: Hand Held Portable Firefighting Equipment, Rev 20, §3.2- The number in front of the letter is the fire test rating, not a size. In the UK it comes from the BS EN 3-7 fire tests; in the US from UL 711.
On successful completion of the tests, a fire test rating is awarded to the extinguisher, and this is indicated on the instruction label (e.g. 13A, 34B, 15F).
London Fire Brigade (London Fire Commissioner), Fire Safety Guidance Note GN08: Hand Held Portable Firefighting Equipment, Rev 20, §5.1The number before the “A” represents a multiple of 1.25 gallons of water whereas the number before the “B” represents a multiple of the area or size in square feet of fire to be extinguished.
US Fire Administration (FEMA), Choosing and Using Fire Extinguishers, ‘How to read the classification label’
Other fire classes
Sources
Official guidance only: UK government, UK fire and rescue services, the Fire Industry Association, NFPA, OSHA and the US Fire Administration. Words in quotation marks are theirs.
- HM Government (GOV.UK): Fire safety risk assessment: offices and shops (accessible version) (updated 12 September 2023). Quoted here: Part 2, 3.1, Table 1: Class of fire. www.gov.uk Checked 2026-09-29.
- London Fire Brigade (London Fire Commissioner): Fire Safety Guidance Note GN08: Hand Held Portable Firefighting Equipment, Rev 20 (January 2025). Quoted here: §3.2 (after BS EN 2); §3.2; §5.1. www.london-fire.gov.uk Checked 2026-09-29.
- National Fire Protection Association (NFPA): Fire Extinguisher Ratings (NFPA Today blog, Brian O’Connor) (26 August 2022). Quoted here: table of classes. www.nfpa.org Checked 2026-09-29.
- HM Government (GOV.UK): A guide to making your small non-domestic premises safe from fire (accessible version) (updated 20 January 2025). Quoted here: section ‘Fire extinguishers’. www.gov.uk Checked 2026-09-29.
- US Fire Administration (FEMA): Choosing and Using Fire Extinguishers (page last reviewed 1 April 2023). Quoted here: ‘Help people decide when to use a fire extinguisher’; ‘How to read the classification label’. www.usfa.fema.gov Checked 2026-09-29.
- US Occupational Safety and Health Administration (OSHA): eTool: Evacuation Plans and Procedures, Portable Fire Extinguishers, Extinguisher Basics (no date shown). Quoted here: Carbon dioxide extinguishers. www.osha.gov Checked 2026-09-29.
- National Fire Protection Association (NFPA): What Is a Class K Fire Extinguisher? (NFPA Today blog, Brian O’Connor) (12 August 2024). Quoted here: ‘Where should I install Class K fire extinguishers?’. www.nfpa.org Checked 2026-09-29.