Class
A
rating fire extinguishers are often water-based, and are
highly effective in extinguishing burning materials found or
stored in an office or warehouse for example. Water-based
Class A extinguishers may also have additives to make them
more effective.
Class
B
rating fire extinguishers are usually foam fire extinguishers or
powder. These extinguishers work by not only
extinguishing flames but also sealing in any potentially
dangerous vapours.
Class
C
rating fire extinguishers will be dry powder fire
extinguishers that are capable of separating the
elements of thee fire triangle.
Class
D
rating fire extinguishers are highly specialized
extinguishers, designed to be used on specific metal fires
with such exotic names as M28, L2 and Purple-K. They will have a
long lance with a low velocity application on the
end.
Class
E rating
fire extinguishers are specially designed for use on
live electrical
equipment. While a powder fire extinguisher is
non-conductive and safe to use, the most popular fire
extinguisher for use on electrical equipment fires is carbon
dioxide, which extinguishes flames without causing further
damage.
Class
F
rating fire extinguishers, also known as wet chemicalfire
extinguishers, are specifically for fires involving
cooking oils and
fats.