The Different Types of Fire Extinguishers

Humankind has been using fire for millennia. It is one of our most useful discoveries, one which we use to our advantage for our own survival and protection. However, fire also presents a serious danger to our lives and properties.

One of our most common household defenses against domestic fires is the fire extinguisher. Although not recommended for use on out-of-control conflagrations, fire extinguishers are useful against small fires.

A fire extinguisher typically consists of a cylindrical pressure vessel which holds the fire-fighting chemical. There are several basic types of fire extinguishers according to the Fire Equipment Manufacturer’s Association. Each one of them uses a different fire-fighting agent designed to deal with one or more elements of the fire triangle, the three things that have to be present for a fire to take place:

Heat
Oxygen (from the air)
Fuel (the thing that can burn, e.g wood, cotton, coal, etc.)

Each of the fire extinguishers is formulated to deal with specific types of fires only. Fires are classified according to the following criteria:

Class A – Includes ordinary combustibles like paper, cloth, wood, plastics, and garbage
Class B– Includes inflammable liquids like gasoline, inflammable paint, and petroleum oil. Inflammable gases like butane and propane are also included in this category.
Class C – Includes energized electrical elements like household appliances, motors, and transformers.
Class D – Includes fires in combustible metals like aluminum, magnesium, sodium, and potassium.
Class K – Includes fires in cooking oils or greases like animal fats and vegetable oils.

Take note of the different types of fire extinguishers and the types of fires they can extinguish:

Water and Foam –For Class A fires.
Carbon Dioxide –For Class B and C fires.
Dry Chemical –Multipurpose dry chemical fire extinguishers are for Class A, B, and C fires. Ordinary dry chemical can be used on Class B and C fires only.
Wet Chemical –For Class K fires and some Class A fires, depending on manufacturer specifications.
Halogenated or Clean Agent –For Class B and C fires. Some clean agent fire extinguishers can also be used on Class A fires, depending on manufacturer specifications.
Dry Power – For Class D fires
Water Mist – Primarily for Class A fires, although it is also safe for use on Class C fires.
Cartridge-Operated Dry Chemical – Multipurpose dry chemical can be used on Class A, B, and C Fires. Ordinary dry chemical is for class B and C fires only.

The correct type of fire extinguisher must be used on the right type of fire. Otherwise, there is a chance for a fire to reignite after apparently being put out successfully.

For more articles on fire safety, please visit the Fire Alarm Houston blog.