Fire safety
Fire Extinguisher Calculator
UK sizing is a simple product: floor area times 0.065 gives the Class A rating you must provide, split across at least two extinguishers per storey.
Calculator
Fill in the fields above to see results.
How it works
Enter the floor area and your extinguisher rating (a standard 9 L water or 6 L foam is 13A). The tool divides the required rating, rounds up, and enforces the two-per-storey minimum and 30 m travel distance rule.
Frequently asked questions
How many fire extinguishers per floor?
BS 5306-8: enough Class A rating to cover 0.065 x floor area, and never fewer than two per storey. A 400 m2 floor needs 26A - two 13A extinguishers.
Is the US rule the same?
No - NFPA 10 works from hazard class and a 75 ft travel distance rather than the 0.065 formula. This calculator implements the UK BS 5306-8 method.