Operational Characteristics of Portable Fire Extinguishers

There are five classes of fires and there are fire extinguishers that are best-suited to extinguish each class. Each type of extinguisher has some sort of hazard.

Classes of Fires

• Class A: Signified by a green triangle, it involves common materials such as wood, paper and most other combustibles.

  Class B: Signified by a red square, it involves flammable liquids such as gasoline, paint stripper and grease.

  Class C: Signified by a blue circle, it involves electrical fires.

  Class D: Signified by a yellow five-point star, it involves combustible metals most commonly found in industries.

  Class K: There is no signification for a Class K fire, which involves vegetable oils or animal oils or fats in cooking appliances.

Extinguisher Types

• Water extinguishers have an effective range of 23 feet and should be used for Class A fires.

  Foam extinguisher have an effective range of 16 feet and should be used on Class B fires.

  Carbon dioxide (CO2) extinguisher have an effective range of 3 to 7 feet and should be used on both Class A and B fires.

  Dry chemical extinguishers have an effective range of 13 to 16 feet and should be used Class A, B and C fires.

  Halon extinguishers have an effective range of 4 to 6 feet and should be used on Class B and C fires.

  Wet chemical extinguishers have an effective range from 10 to 12 feet and should be used on Class A, C and K fires.

  Class D Type 1 extinguishers have an effective range from 6 to 8 feet and should be used on magnesium, sodium, potassium, sodium potassium alloys and powdered aluminum fires.

  Class D Type 2 extinguishers have an effective range from 6 to 8 feet and contain dry powder mixed with copper to smother a fire.

Extinguisher Dangers

• Water extinguishers should not be used on oils, fats or liquid fires or electrical fires.

  Foam extinguishers should not be used on electrical fires, flammable liquids or pressurized gas fires.

  Carbon dioxide (CO2) extinguishers can cause asphyxiation in enclosed areas. The discharge may freeze tissue and cause severe chemical burns if handled incorrectly.

  Dry chemical extinguishers can cause lung irritation if the dry chemical is inhaled.

  Halon extinguishers may result in asphyxiation with extended exposure.

  Wet chemical extinguishers should not be used on Class B fires.

  Class D Type 1 extinguishers contain sodium chloride and sand, so avoid contact with your eyes.

  Class D Type 2 extinguishers contains copper, so avoid inhalation.

Operation

• In order to use an extinguisher properly, use the P.A.S.S. method--Pull pin, Aim at base of fire, Squeeze handle, Sweep from side to side.

Maintenance

• Keep your extinguisher accessible. Maintain proper pressure levels. Keep pin intact until use. Recharge as soon as possible after use. Replace immediately if damaged in any way.