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
| Criteria | 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 6.2.1.1 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 6.3.1.1 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 the fire or the fire surrounds electrical equipment..
Class D Locations
Class D extinguishers 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 mandates the maintenance of fire protection equipment in good working order along with inspection, testing and maintenance records. Inspections are performed on an annual basis.
Examples of work performed during an inspection include:
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- 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 previous 6−year maintenance inspection dates 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 and tear.
- Check the condition of the discharge horn.
- Check for obstructions that interfere with the 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 the unit and ensure that it is properly located at the required height and within the normal travel path.
- Check that the unit is visible, unobstructed and in the 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 the inspection and any necessary repairs, the appropriate inspection documents and deficiencies noted are left at the location and made available electronically.
- Tag all portable fire extinguishers as required and perform required record keeping.
Extinguisher Type
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- 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
- 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

