1. Fire Extinguisher Use
WRDSB Specialist High Skills Major
SHSM Transportation Certificate
Part 1: How Fire Extinguishers Work

2. A fire requires three elements in
order to burn:
1.A fuel source
2.Oxygen
3.Heat
Fire extinguishers
eliminate one of these
three elements

3. How Do Fire Extinguishers Work ?
Compressed gas is released pushing the
extinguishing material out of the nozzle at a
high pressure

4. Fire Classification
There are 4 classifications of fires
Class A: fires involving ordinary combustible materials
such as paper, wood, cardboard and plastic
Class B: fires involving combustible liquids such as
gasoline, grease and oil
Class C: fires involving electrical equipment such as
circuit breakers, wiring and appliances
Class D: fires involving minerals and chemicals such as
sodium, magnesium and potassium

5. Different Types of Fire Extinguishers
Water Extinguishers : Used for Class A fires only
Filled with tap water
Pressurized with air
Dry Chemical Extinguishers: Used for Class A, B and C fires
Filled with baking soda or potassium bicarbonate
Pressurized with nitrogen
Carbon Dioxide (CO2)Extinguishers: Used for Class B and C fires
Filled with CO2, a non-flammable, very
cold gas
Highly pressurized

6. Different Types of Fire Extinguishers
Class D fire extinguishers:
These extinguishers are specifically
designed for Class D fires only

7. Fire Extinguishing Agents
When selecting the appropriate fire extinguisher, it is important to consider
the extinguishing agent contained in the extinguisher
Multi-purpose Dry Chemical: used in homes, schools, offices
Regular Dry Chemical: used in commercial kitchens, laboratories,
garages
Carbon Dioxide: used in computer rooms, processing plants, food
storage areas
Halotron: (requires no clean-up) used in telecommunications areas,
theatres
Purple Dry K Chemical: used in military facilities, vehicles, oil companies
Water: used for stockrooms, office supply rooms