Characteristics of Fires/Types of Extinguishers

CLASSIFICATIONS OF FIRES AND FIRE EXTINGUISHERS
 
Fires and fire extinguishers are classified as A, B, or C:
 
CLASS A:  Water possesses the greatest cooling effect of any
          ordinary and readily available known substance;
          therefore, since a cooling effect is required for
          Class 'A' fires, water is used as the principal
          content of all Class 'A' or cooling type 
          extinguishers.
 
CLASS B:  A wide variety of dense, heavier than air gases,
          powdered chemicals and foam producing substances
          are used in Class 'B' extinguishers.  All of them 
          smother Class 'B' fires by excluding air.
 
CLASS C:  Class 'C' extinguishers use a non-conductive
          extinguishing agent.
 
CHARACTERISTICS OF FIRES   
      
CLASS A:  Fires in ordinary combustibles such as paper, wood,
          cloth, etc., which are normally best extinguished
          by cooling.
 
CLASS B:  Fires involving flammable liquids, such as 
          gasoline, oil, alcohol, benzine, ether, etc., which
          are best extinguished by smothering. 
 
CLASS C:  Fires involving electrical equipment appliances and 
          wiring in which the use of a non-conductive 
          extinguishing agent prevents injury.


 
TYPES OF EXTINGUISHERS
 
CLASS A:  1. Soda Acid
          2. Water tank with gas cartridge 
          3. Water pump tank
          4. Hose lines
 
CLASS B:  1. Foam 
          2. Carbon Dioxide (CO2)
          3. Dry Chemical
 
CLASS C:  1. Carbon Dioxide (CO2)
          2. Dry Chemical
          3. FE 36
 
It is important to use the correct type of extinguisher on 
the fire.  Extinguishers should be of the type most suitable 
for the class of fire which may occur in their locality.  The 
wrong type may fail not only to extinguish fire, but may 
increase personal hazard from electric shock, poisonous 
fumes, spreading of fire, destruction of equipment, or 
explosion. 
 
The following acronym is recommended as a reminder of the 
best method for safe use of a fire extinguisher:
 
P   Pull safety pin
A   Aim nozzle
S   Squeeze 'trigger'
S   Sweep side-to-side at base of flame

Approved By Governing Board    
DP.7
Control #191.0
GUPTA GASTRO