How to Choose the Right Fire Extinguisher by Fire Class
The wrong extinguisher can make a small fire worse instead of putting it out. Here is how to read the fire class and match the right unit to each setting, from the kitchen line to the mechanic's bay.
The five fire classes in Canada
In Canada, fires are classed by what is burning, and that class decides which extinguishing agent is safe to use. A unit built for one class can be useless, or even dangerous, on another.
- Class A: solid materials such as wood, paper and textiles
- Class B: flammable liquids such as gasoline, oil and paint
- Class C: energized electrical equipment
- Class D: combustible metals such as magnesium and sodium
- Class K: cooking fires, meaning vegetable or animal oils and grease
Extinguisher types and what they handle
Each agent has a purpose. The pictogram on the label tells you which classes it covers. Before you buy, look at what could actually catch fire in the room.
- Pressurized water: Class A only. Keep it away from electrical and flammable-liquid fires, since water conducts current and spreads the liquid
- ABC dry chemical: Classes A, B and C. The most common and versatile choice, but the powder is corrosive and can damage electronics
- CO2: Classes B and C. Leaves no residue, ideal for server rooms and computer equipment
- Class K: cooking-oil and grease fires. Required in Quebec commercial kitchens
The right extinguisher by setting
The choice gets simple once you start from the room and what is in it. Here are the pairings we install most often in the field.
- Commercial kitchen: a Class K unit near the fryers and ranges, on top of the fixed system under the hood. A residential kitchen unit may combine ABC and K
- Garage and mechanic's shop: ABC powder to cover oil, gasoline (Class B) and electrical (Class C) in one spot
- Office: an ABC near the exits for furniture and paper, plus a CO2 near servers and sensitive electronics
- Welding shop or light-metal machining: add a Class D unit if magnesium, titanium or metal shavings are present
Placement and upkeep
The best extinguisher is worthless if it is hidden, blocked or expired. In Quebec, the National Fire Code and the NFPA-10 standard govern how portable extinguishers are mounted, kept visible and maintained.
An annual inspection by a professional is expected, and a monthly visual check by staff is good practice. Internal maintenance (6 years) and hydrostatic testing also apply depending on the unit type.
- Keep the extinguisher visible, clear and reachable at all times
- Keep maintenance records current
- Train staff on basic use and technique
- Recharge or replace any unit that has been used or discharged, without delay
Common mistakes to avoid
Most of what we flag on inspection comes from poor pairing or weak follow-up, not from a shortage of units.
- Throwing water on a fryer fire, which sprays burning oil
- Relying on one ABC for a commercial kitchen where Class K is required
- Blocking access with stock or boxes
- Losing track of the inspection date and letting a unit fall out of compliance
Your proof of compliance stays with you in the Canuck360 portal. Discover Canuck360 Frequently asked questions
Can a single ABC extinguisher cover my whole building?
For many ordinary-hazard spaces, an ABC covers Classes A, B and C, so it does most of the work. But it does not replace a Class K in a commercial kitchen or a Class D where combustible metals are present. The right answer depends on the setting and the materials on site, which an on-site assessment confirms.
Why is a Class K extinguisher required in a Quebec commercial kitchen?
Cooking oils and grease burn at very high temperatures and reignite easily. A Class K agent cools them and forms a layer that smothers the fire, which an ABC does not do well. Quebec regulations require it for commercial kitchens, alongside the fixed system under the hood.
How often should my extinguishers be inspected?
An annual inspection by a professional is the baseline, with a monthly visual check by your staff. Depending on the type, internal maintenance every 6 years and hydrostatic testing also apply. To keep nothing slipping, the Canuck360 portal stores all your dates and reports in one place.
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