In workplaces across Canada, fire extinguishers are a critical first line of defense in fire safety. This month’s safety update will walk you through what they do, when they’re required, how to choose the right one, and how to use them safely.
How Fire Extinguishers Work
A fire extinguisher is a portable device designed to control or extinguish small fires in their early stages before they spread out of control. It works by releasing a substance such as water, foam, carbon dioxide (CO₂), dry chemical powder, or a wet chemical that removes one or more elements needed for a fire to burn:
- Heat
- Fuel
- Oxygen
- Chemical reaction
By removing one of these elements, the fire can’t continue to burn.
When Fire Extinguishers Are Required
Under the National Fire Code of Canada and provincial fire codes, portable fire extinguishers must be provided in all workplaces where there is a risk of fire. This includes, but is not limited to locations where:
- Combustible or flammable materials are stored or handled.
- Electrical equipment could overheat or spark.
- Work activities involve hot work, open flames, or cooking appliances.
- Workers may need to control a fire in its early stages before emergency responders arrive.
In Alberta, the OHS Code also requires employers to ensure workers are trained in the safe use of firefighting equipment, not just the requirement for extinguishers to be present.
Types of Portable Fire Extinguishers
Different fire extinguishers serve different purposes, so it is critical to choose the right fire extinguisher for the fire as selecting the wrong type can make a fire worse. Fire extinguisher type is based on the class of the fire itself and the materials that are burning.
| Fire Extinguisher Type | Suitable Classes | Notes |
| Water | A | Never use on electrical or flammable liquid fires. Removes heat from burning materials. |
| CO₂ | B, C | Displaces oxygen; avoid use in confined spaces without respiratory protection. |
| Dry Chemical (ABC, BC) | A, B, C | Most common type. Smothers flames. Leaves residue. |
| Chemical Foam | A, B | Works on solids and flammable liquids. Leaves residue. |
| Dry Powder | D | For combustible metals only; must be compatible with the metal present. |
| Wet Chemical | K | Designed for cooking oil/fat fires; prevents re-ignition. |
Installation and Placement Distance
Fire extinguishers must be readily accessible, clearly marked, and located within the maximum travel distances allowed by fire codes. Extinguishers must be installed at least 4 inches off the ground to a maximum of 5 feet. The exception to this rule is for extinguishers heavier than 40lbs, which can only be up to 3.5 feet off the ground.
The maximum distance is based on the fire class:
| Classes of Fires | Distance Requirements |
| Class A – Ordinary combustibles (paper, wood, cloth, rubber, plastics) Class B – Flammable liquids/gases (oil, paints, solvents) Class C – Energized electrical equipment (motors, appliances, wiring) Class D – Combustible metals (magnesium, titanium, sodium, potassium) Class K – Cooking oils/fats in appliances | Class A: 75 feet maximum travel distance Class B: 30 to 50 feet maximum travel distance, depending on anticipated hazard and B rating. Class C: Extinguishers are never solely class C. Distance determined by underlying Class A or B hazard. Class D: 75 feet maximum travel distance Class K: 30 feet maximum travel distance |
How to Use a Fire Extinguisher – P.A.S.S.
Before using, make sure:
- The fire is small and not spreading.
- You have a clear escape route.
- You can stay approx. 6 ft away from the fire.
- P – Pull the pin.
- A – Aim at the base of the fire.
- S – Squeeze the handle to discharge.
- S – Sweep from side to side until the fire is out.
Remember to always keep your back to the exit in case quick evacuation is necessary.
Inspection and Maintenance
Monthly inspections should confirm:
- The extinguisher is in its designated location.
- No obstructions to access.
- Pressure gauge is in the operable range.
- Pin and seal are intact.
- No physical damage or corrosion.
- Label and operating instructions are legible.
Annual maintenance must be performed by a certified technician in accordance with NFCC requirements, and detailed records must be kept. Extinguishers that are damaged, discharged, or exposed to fire must be removed from service immediately.
Key Takeaway
Fire extinguishers are a simple yet powerful tool in workplace fire safety when they are used safely. Using the right type, and making sure they are correctly located, properly maintained, and used by trained personnel can help to increase the effectiveness of fire extinguishers. Employers are responsible for ensuring both the equipment and the training are in place to protect workers from fire hazards.