How Many Extinguishers are Required?

There are four topics to review when installing portable fire extinguishers. You must first identify the hazards that are present, and recognize even trace amounts of each fire classification to determine the proper number of extinguishers required. Next, you must determine the size of the fire extinguisher, and establish the quantity of extinguishers needed by the coverage allowed per Local and National fire codes. Last, you must distribute the portable fire extinguishers per the allowable travel distance to each fire extinguisher.


Class A Locations



Light (Low) Hazard Occupancy

Ordinary (Moderate) Hazard Occupancy 

Extra (High) Hazard Occupancy

Minimum Rated single extinguisher  2-A 2-A 4-A
Maximum floor area per unit of A  3,000 ft2 1,500 ft2 1,000 ft2
Maximum floor area for extinguisher  11,250 ft2 11,250 ft2 11,250 ft2
Maximum travel distance to extinguisher 75 ft 75 ft 75 ft


 Source: NFPA 10, 2007 edition Table Fire Extinguisher Size and Placement for Class A Hazards

Class B Locations


Type of Hazard 

Basic Minimum Extinguisher Rating 

Maximum Travel Distance to Extinguisher 

  5-B 30 ft
Light (Low)  10-B 50 ft
  10-B 30 ft
Ordinary (Moderate)  20-B 50 ft
  40-B 30 ft
Extra (High)  80-B 50 ft



Source: NFPA 10, 2007 edition Table Fire Extinguisher Size and Placement for Class B Hazards

Class C Locations

Class C extinguishers are required where energized electrical equipment is directly involved in or surrounding electrical equipment.


Class D Locations

Class D extinguisher locations shall not be located more than 75 ft. from the hazard. Size determination for Class D locations is based on the specific combustible metal, particle size, area to be covered, and manufacturer recommendations.


Class K Locations

Class K hazards shall have a fire extinguisher located where there is a potential for a fire involving combustible cooking media (vegetable or animal oils and fats). The extinguisher shall be located no more than 30 ft. from the hazard.

NFPA 10 requires you to maintain your fire protection equipment in good working order and maintain inspection,
testing and maintenance records. Inspections will be performed on an Annual basis.


  • Check that unit is properly hung with the proper manufacturer’s hanger.
  • Check the gauge pressure.
  • Check the condition of the gauge and its compatibility with the extinguisher.
  • Check the weight of the extinguisher.
  • Check that the last hydrostatic test date is within code requirements.
  • Check the last 6−year maintenance inspection date if applicable.
  • Check the valve and shell for damage or corrosion.
  • Remove the hose and inspect it for cracks or splits.
  • Check the hose threads for signs of wear.
  • Check the condition of the discharge horn.
  • Check for obstructions that interfere with accessibility of the unit.
  • Break the extinguisher seal and remove the locking pin.
  • Replace the locking pin and reseal the extinguisher.
  • Check the valve opening for powder or any foreign matter.
  • For dry extinguishers, fluff the powder by turning the unit.
  • Check the condition of the hose/horn retention band at the side of the extinguisher.
  • Check that the unit’s classification is properly identified with the appropriate decal/signage.
  • Check that the operating instructions are clean and legible.
  • Check that the unit is properly located within the normal path of travel, at the required height.
  • Check that the unit is visible, unobstructed and in proper location.
  • Compile a complete location report, explaining any deficiencies.
  • Recommend corrective action to be taken in accordance with recognized codes for care and maintenance.
  • Upon completion of inspection and any necessary repairs, applicable inspection documents and noted deficiencies shall be left at location and available electronically.
  • Tag all portable fire extinguishers as required and perform required record keeping.

 Extinguisher Type

Test Interval (years) 

Stored-pressure water, water mist, loaded stream, and/or anti-freeze 
Pump tank water and pump tank calcium chloride base 
Dry chemical, cartridge and cylinder operated, with mild steel shells 
Dry powder, cartridge and cylinder operated, with mild steel shells 
Wetting agent 
Stored pressure water   5
Stored-pressure dry chemical, with stainless steel shells   
Carbon dioxide 
Wet chemical 
Dry chemical stored-pressure, with mild steel shells, brazed brass shells, and aluminum shells 
Halogenated agents 
Dry powder, stored pressure, with mild steel shells 
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