There are several different types of fires, which means there are different types of fire extinguishers as well. A wood fire burns differently from an oil fire, for instance. You probably already know this from the old adage about never throwing water on a grease fire. Water puts out a wood fire, but only spreads a grease fire. A fully monitored fire alert system and sprinkler system are your best defenses against a widespread fire, but extinguishers can help keep employees safe and deal with small fires before they become larger.

Class A Fire Extinguisher: These put out paper, wood, and plastic fires. These are the kinds of fires which might start if someone throws a spent match or cigarette into a trash can before it’s cooled off. These are common in any building environment.

Class B Fire Extinguisher: These put out fires that are feeding off of flammable liquids like oil, gasoline, or grease. These fires are sparked by a number of causes. Grease fires are common in restaurant kitchens, while oil and gasoline fires are a risk in many industrial work environments.

Class C Fire Extinguisher: This is reserved for electrical fires. Electrical fires are some of the most dangerous listed here. You can put out the fire, but the source that sparked it can still be extremely dangerous. This can happen in any environment, particularly if wiring is old or not properly maintained.

Class D Fire Extinguisher: This has to do with fires caused by combustible metals. Sodium and magnesium are two examples. These kinds of fires may be a risk in laboratories, plants, and chemical storage facilities.

Almost every fire extinguisher works the same way. You pull the pin to break its tamper seal, aim the extinguisher’s nozzle at the base of the fire, squeeze the handle, and sweep the nozzle side-to-side.

You can remember this as PASS: Pull, Aim, Squeeze, Sweep. Repeat until the fire has been put out.

An extinguisher is meant to put out small fires, to contain them from spreading, or to secure a safe exit for people. It is not meant for workers to risk themselves trying to put out an overwhelming fire that has already spread. This is why you have a fully monitored fire alert system and a sprinkler system.