Portable Extinguisher Count + Placement Calculator

Too few extinguishers, the wrong class in the kitchen, or a unit hung too high are the most common write-ups on an annual fire inspection. Enter each floor's area, the hazard class, and the rating on the label — this tool applies NFPA 10-2022 Table 6.2.1.1 to compute the minimum Class A count per floor, checks Class B and Class K travel distance, and gives the mounting height for the unit weight.

Educational estimator. Not a sealed design and not a substitute for a walk-through by the fire marshal or a licensed extinguisher technician. Counts below are the code-minimum from area math per NFPA 10-2022 Table 6.2.1.1 and IFC 2021 §906; the 75-ft travel distance usually requires more units than the area math alone. Texas jurisdictions adopt different code editions and local amendments govern — confirm the adopted edition with your AHJ.

A — Class A: ordinary combustibles, by floor

Hazard classification (applies to every floor) NFPA 10 §5.4 examples. Light: offices, classrooms, churches, hotel guest rooms. Ordinary: mercantile, light manufacturing, parking garages, restaurant dining, auto showrooms, warehouses of non-combustible goods. Extra: woodworking, vehicle repair, aircraft servicing, flammable-liquid handling, high-piled combustible storage, upholstered furniture manufacturing. When in doubt, pick the higher hazard.

Class A rating of the extinguisher you plan to install Read the rating off the UL label on the cylinder. "3-A:40-B:C" means 3 units of A, 40 units of B, rated for Class C. Common units: 5 lb ABC = 2-A or 3-A; 10 lb ABC = 4-A; 20 lb ABC = 10-A; 2.5 gal water = 2-A.

One row per floor. NFPA 10 §6.2.1.2.1 computes the count floor by floor — floors are never pooled.

B — Class B: flammable liquids and gases (optional)

This building has Class B hazards Fuel storage, paint, solvents, generator rooms, vehicle service, lab chemicals. Most offices and classrooms do not need this section.

C — Class K: commercial cooking (optional)

This building has commercial cooking with combustible cooking media Deep-fat fryers, griddles, ranges, woks using vegetable or animal oils and fats (NFPA 10 §6.6.1). A break-room microwave does not count.

D — Mounting height

Gross weight of the extinguisher (lb) Gross (full, charged) weight from the label or spec sheet, not the agent weight. A "10 lb ABC" typically weighs 16–18 lb gross; a "20 lb" unit typically 30–35 lb gross. Wheeled units are excluded from this height rule.

Extinguisher count and placement

Class A — per floor (NFPA 10 Table 6.2.1.1)

Class A required (all floors) —

Travel distance check CHECKCount is the floor of the answer — walk the floor: no point may be more than 75 ft actual walking distance from an extinguisher (§6.2.1.1, Table 6.2.1.1; measured along the walking path, not straight line — NFPA 10 Annex A, definition of travel distance). Planning aid, not code: a 75-ft travel radius covers at most roughly 11,250 sf of open floor, which is why the table caps there. 75 ft max

Class C — energized electrical equipment (NFPA 10 §6.4)

No separate count. Where energized electrical equipment is present, the extinguishers must carry a Class C rating (the "C" on the label); size and placement follow the Class A or Class B hazard that is actually present. An ABC-rated unit satisfies this. C rating

Placement and upkeep

Extinguishers must be conspicuously located, readily accessible, and along normal paths of travel, including exits (§6.1.3.1, §6.1.3.2). Where visual obstructions cannot be avoided, provide signs or other means to indicate the extinguisher location (§6.1.3.3).

Once installed: monthly visual inspection §7.2, annual maintenance by a certified person §7.3, 6-year internal examination for stored-pressure dry chemical units (§7.3.3), hydrostatic testing per Chapter 8.

Show the math

Code cited: NFPA 10-2022 §6.2.1, Table 6.2.1.1 (Class A size and placement); §6.3.1, Table 6.3.1.1 (Class B); §6.3.2 (appreciable depth); §6.6.2 (Class K); §6.1.3.8 (mounting height); IFC 2021 §906 (where required; Table 906.3(1) reproduces the NFPA 10 Class A table and §906.3 points to NFPA 10 for placement).

Portable Extinguisher Count + Placement Calculator

Extinguisher count and placement

Class A — per floor (NFPA 10 Table 6.2.1.1)

Class B — flammable liquids (NFPA 10 Table 6.3.1.1)

Class K — commercial cooking (NFPA 10 §6.6)

Class C — energized electrical equipment (NFPA 10 §6.4)

Mounting height (NFPA 10 §6.1.3.8)

Placement and upkeep

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