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Fire extinguisher placement calculator for NFPA 10.

Pick the hazard classification and enter the floor area. The calculator gives the minimum number of Class A extinguishers by the NFPA 10 area rule, the travel distance to each, and the Class B, K and D rules where flammable liquids, cooking or combustible metals are present. Free from FireInspection360, the fire prevention platform built by fire inspectors.

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How many extinguishers, and how far apart

NFPA 10 Table 6.2.1.1 (Class A) and Table 6.3.1.1 (Class B), and the travel distances OSHA adopts in 29 CFR 1910.157(d). The count is a floor: the travel distance decides the placement on the floor plan.

Light (low) hazard: offices, classrooms, churches, assembly halls, hotel guest rooms. Ordinary (moderate) hazard: retail, light manufacturing, research, parking garages, warehouses of Class I or II commodities. Extra (high) hazard: woodworking, vehicle repair, aircraft servicing, cooking areas, warehouses of high-hazard commodities.

A common 5 lb ABC dry chemical extinguisher is rated 2-A or 3-A; a 10 lb unit 4-A; a 20 lb unit 10-A. Read it off the label.

Pick the hazard classification and enter the floor area. The minimum number of Class A extinguishers, the travel distance to each, and the Class B, K and D rules that apply appear here.
This is a calculation aid, not a determination. Verify it against the code your jurisdiction has adopted, including any local amendments, before it is relied on. NFPA 10 as adopted by your jurisdiction governs; the fire code official may require more where the hazard warrants it, and a listed extinguisher's rating comes from its label.
How it works

Two rules decide extinguisher placement, and the stricter one wins.

NFPA 10 sizes and places portable extinguishers for Class A fires (ordinary combustibles) with two rules that both have to be met. The area rule in Table 6.2.1.1 says how much floor each unit of Class A rating may cover: 3,000 square feet per unit of A in a light hazard occupancy, 1,500 in ordinary hazard and 1,000 in extra hazard, so a 2-A extinguisher covers 6,000 square feet of an office and 3,000 of a warehouse. Whatever its rating, one extinguisher never covers more than 11,250 square feet. The travel distance rule says no point on the floor may be more than 75 feet of actual walking distance from an extinguisher. A long, narrow floor or one cut up by walls needs more extinguishers than the area rule gives, because the area rule cannot see the walls.

Flammable liquids and gases are a Class B hazard with their own table. Table 6.3.1.1 pairs a minimum rating with a travel distance, and a smaller unit has to be closer: in an ordinary hazard occupancy a 10-B within 30 feet of the hazard or a 20-B within 50 feet. Electrical equipment (Class C) adds a C rating to the extinguishers already placed for the Class A or B hazard rather than a separate distance; commercial cooking appliances need a Class K extinguisher within 30 feet in addition to the hood suppression system; and a shop that generates combustible metal powders or shavings needs a Class D agent within 75 feet, listed for the specific metal.

OSHA adopts the same distances in 29 CFR 1910.157(d) for every workplace, which is why the extinguisher question comes up on a fire inspection and an OSHA visit alike. Mounting height, monthly quick checks, the annual maintenance tag and the six- or twelve-year internal examination are the rest of the standard, and an inspector reads the tag before the placement.

How FireInspection360 tracks the rest of the standard

The placement is a one-time design question. The annual maintenance is a recurring one, and it belongs on the property record: FireInspection360's inspection checklists carry the extinguisher items every inspector checks, violations come with photos, and the business fixes them and sends proof of correction from its own portal.

See how inspections work in FireInspection360

Related tools: the occupant load calculator and the egress requirements calculator.

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