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How Many Fire Extinguishers Do You Need?

By Frank Jones··2 min read

Got a commercial building? You need fire extinguishers. But how many?

The answer isn't just about square footage. It's about travel distance, fire hazard types, and building use.

The Basic Rule

NFPA 10 doesn't set requirements by square feet. Instead, it uses travel distance - how far someone has to walk to reach an extinguisher.

For most buildings:

  • Class A fires (ordinary materials): 75 feet max travel distance
  • Class B fires (flammable liquids): 50 feet max travel distance
  • Class K fires (cooking oils): 30 feet max travel distance

What This Means for Your Building

Small Offices (Under 3,000 sq ft)

  • Usually need 2-4 extinguishers
  • One near each exit
  • Additional units for storage areas

Medium Buildings (3,000-10,000 sq ft)

  • Typically need 6-12 extinguishers
  • Strategic placement in hallways
  • Extra units in mechanical rooms

Large Buildings (Over 10,000 sq ft)

  • Plan for 1 extinguisher per 1,500-3,000 sq ft
  • Depends heavily on layout and hazards
  • Professional assessment recommended

Special Considerations

High-Hazard Areas

Some spaces need more protection:

  • Kitchens require Class K extinguishers every 30 feet
  • Server rooms may need special clean agent units
  • Warehouses storing flammable materials need closer spacing

Building Layout Matters

  • Long corridors need multiple units
  • Multi-story buildings need extinguishers on every floor
  • Dead-end hallways over 20 feet need dedicated units

Quick Calculation Method

For standard office buildings, use this rough estimate:

  1. Measure your building's longest dimension
  2. Divide by 150 feet (half the 75-foot travel distance)
  3. Round up to get minimum extinguishers needed per floor

Example: 300-foot building ÷ 150 = 2 extinguishers minimum per floor

Don't Guess - Get It Right

Fire marshals are picky about extinguisher placement. Too few units or wrong placement means citations and fines.

Consider hiring a fire protection professional for buildings over 5,000 square feet. They'll create a proper placement plan that meets all codes.

Your insurance company and employees will thank you for getting it right the first time.