Most folks have seen fire extinguishers and know what they do, but fewer people have actually handled them and know how to use them. Knowing a thing or two about these handy devices and ensuring they are visible in your workplace can save an entire shop from going up in flames and in some cases, they can save lives.

It is recommended that a fire extinguisher be kept in the kitchen, the garage, and the workshop. That’s a minimum of three extinguishers per household, and in larger shops with more than one entrance, consider placing extinguishers in all four corners.

But, it’s not enough to have them just lying around. Extinguishers need to be routinely inspected – quickly checked on a monthly basis to make sure they are fully charged and unobstructed, and maintained – and receive a more thorough examination annually, ensuring the extinguisher is not leaking or in need of replacement.

Extinguishers come in different sizes, numerical ratings, and classifications. The numerical rating refers to the size of fire an extinguisher can put out, while the classification letter states which type of fire the extinguisher is suited for, and what exactly the extinguisher uses to put the fire out.

A class A fire extinguisher is used to put out a class A fire: one caused from combustible materials like paper, wood, cardboard, and plastics. The extinguishers are made of water pressurized by oxygen and must not be used for any other class of fire. Fighting a grease fire with water will only fuel the flames, and using water to fight an electrical fire poses a serious electrical shock risk.

Shop owners should concern themselves more with class B and C types of fire extinguishers. Class B fires are caused by flammable or combustible liquids such as gasoline, kerosene, grease, and oil, while class C fires are electrical fires. The less common, class D fire extinguishers, are commonly found in a chemical laboratory. They are for fires that involve combustible metals such as magnesium, titanium, potassium, and sodium.

Fortunately, combination extinguishers made of dry chemicals are available. Dry chemical extinguishers can be used for any combination of class A, B, and C fires. They are pressurized with nitrogen and filled with foam or powder. The regular type of dry chemical extinguisher, known as a class BC, is filled with sodium bicarbonate or potassium bicarbonate that leaves a mildly corrosive residue – a welcome mess considering the alternative, a pile of ashes. Another type of dry chemical extinguisher, the ABC, is filled with a yellow powdered mono-ammonium phosphate, which can also leave a sticky mess and permanently damage appliances.

So how can you tell if your fire extinguisher is acceptable? Extinguishers need to be free from rust and dents or visible leaks. A pressure gauge should be in the green. It’s recommended that all people in your shop are familiar with the location of your extinguisher(s) and feel comfortable holding and using them. A key to remembering how to use these devices (since, let’s face it, the mind can go blank in the face of emergency) is to recall the PASS technique: Pull the pin from the handle. Aim the nozzle at the base of the fire. Squeeze the handle (you’ll only get about 30 seconds from an average extinguisher), and Sweep the hose as you spray the base of the fire. In that order. Remember: only attempt to fight fires if your instincts are telling you its safe to do so, and if the fire is small and contained. Check to make sure there is an escape route if flames can’t be put out before they escalate, and alert anyone else in the building by pulling an alarm, or doing so vocally if your shop is small.

To cover your shop’s fire protection needs, opt for a BC fire extinguisher in your workplace at minimum. Most come with a ten-year warranty, can be refilled by professionals, and cost less than thirty dollars – a wise investment for peace of mind in the workplace. JM