The National Fire Protection Association (NFPA) establishes requirements for the type, number, size, placement, performance and maintenance of portable fire extinguishers. These requirements are contained in NFPA 10, "Standard for Portable Fire Extinguishers".
Within this standard it is stated that the selection of fire extinguishers for a given situation is determined by the following:
- the character and size of the fires anticipated to be encountered.
- the construction and occupancy of the property to be protected.
- the ambient temperature of the area where the extinguisher will be located.
- other factors that may dictate the selection of a particular type of extinguisher.
Typically, proper fire extinguishers selection is based on the hazard(s) the extinguishers are intended to protect. The Following is a list Classifications that have been established to categorize these hazards as follows:
Fires involving ordinary combustible materials such as wood, cloth, paper, rubber, trash and many plastics.
- This type is common in typical home and commercial settings, but can occur anywhere if these materials are present.
- You can use water, but if not, then use a foam or multi-purpose (ABC-rated) dry chemical extinguisher. Examples below.
- DON’T USE carbon dioxide or ordinary (BC-rated) dry chemical extinguishers.
- Placement and accessibility of fire extinguishers for Class A fires:
- 75 feet maximum area that one extinguisher can protect and meet the 75 ft. rule = 11,250 sq. ft..
Fires involving flammable liquids, combustible liquids, petroleum grease, tars, oils, oil based paints, solvents, lacquers, and alcohols. Does not include fires involving grease and cooking oils..
- • This type often spreads rapidly and can get out of control easily. Furthermore, they have been known to reflash even after the flames are seemingly extinguished.
- Smother these types of fires, which will then deplete the oxygen supply and prevent the vapors from reaching the ignition source.
- Use foam, ordinary (BC-rated) dry chemical extinguishers, multi-purpose dry chemical, carbon dioxide, and halon extinguishers. Examples below.
- Placement and accessibility of fire extinguishers for Class B fires:
- 50 feet maximum area that one extinguisher can protect and meet the 50 ft. rule = 5,000 sq. ft..
Fires involving energized electrical equipment such as wiring, data processing panels, motors, appliances or controls.
- • This type can sometimes be caused by a spark, short circuit, or power surge and, detrimentally, usually occurs in locations that might be difficult to see and reach.
- It’s important to de-energize the circuit first and then use a non-conductive extinguishing agent such as carbon dioxide, ordinary (BC-rated) dry chemical extinguishers, multi-purpose dry chemical, and halon extinguishers.
- Placement and accessibility of fire extinguishers for Class C fires:
- In accordance with the Class A or B hazard it is protecting.
Fires involving combustible metals such as magnesium, sodium, potassium, and sodium potassium alloys.
- This type presents an industrial hazards and therefore requires special dry powder agents.
- Once again, do not use water in to extinguish it. Only use a Dry Powder extinguishing agent specially designated for the material involved. Dry powder agents work by smothering and heat absorption; cooling it below it’s ignition temperature.
- Placement and accessibility of fire extinguishers for Class D fires:
- 75 feet.
Fires involving combustible cooking media such as vegetable oils, animal oils, and fats.
- Particularly hot fires that commonly reflash
- Typically happens in commercial kitchens and so therefore there are regulations to use chemical extinguishing agents that use Purple K, the typical agent found in kitchen or galley extinguishers.
- Placement and accessibility of fire extinguishers for Class K fires:
- 30 feet maximum area that one extinguisher can protect and meet the 30 ft. rule = 1,800 sq. ft..