Classes of Fires
There are four classes of fires. All fire extinguishers are labeled, using standard symbols, for the classes of fires on which they can be used.
A red slash through any of the symbols tells you the extinguisher cannot be used on that class of fire. A missing symbol tells you only that the extinguisher has not been tested for a given class of fire, but may be used if an extinguisher labeled for that class of fire is not available.
The Four Classes of Fire are: