01 — Extinguisher classes
The letter class tells you what type of fire the agent is designed to suppress. Using the wrong class can make a fire worse.
| Class | Fire type | Agent / notes |
|---|---|---|
| A | Ordinary combustibles — wood, paper, cloth, rubber, most plastics | Water or dry chemical; the most common household fire |
| B | Flammable liquids and gases — gasoline, oil, propane, paint, grease | CO2 or dry chemical; never use water on Class B fires — it spreads the burning liquid |
| C | Live electrical equipment — wiring, circuit breakers, appliances | Non-conductive agent (CO2 or dry chemical); the C rating means the agent will not conduct electricity. Once power is off, the material becomes a Class A or B fire. Never use water on electrical fires. |
| K | High-temperature cooking oils and fats — deep fryers, commercial cooking | Wet chemical agent creates a saponification blanket that seals hot oil fires; required by NFPA 10 for commercial kitchens. Standard ABC dry chemical is not effective on Class K fires at these temperatures. |
The ABC dry chemical extinguisher is the most common residential choice and is effective against Class A, B, and C fires. Most households benefit from at least one ABC extinguisher in the kitchen and one in the garage. For a home kitchen where cooking oil fires are a regular risk, a small Class K or Class B:C extinguisher is also worth considering.
02 — The PASS technique
Four steps, in order. Pull the pin before anything else — without it, the handle will not operate.
PASS is the universal operating technique for portable fire extinguishers. A portable extinguisher typically gives you 8 to 30 seconds of discharge. Knowing the technique before a fire means you do not spend those seconds reading instructions.
Maintain a safe distance from the fire — approximately 6 to 10 feet for most portable extinguishers, or per the manufacturer's instructions. Stay low if smoke is present. Keep your back to your escape route.
03 — Placement and inspection
An extinguisher in a cabinet under the sink, behind things, is not an extinguisher you can use in an emergency.
NFPA and fire safety professionals recommend the following for home extinguisher placement: mount near the exit of any room with significant fire risk, at a height of 3.5 to 5 feet, visible and unobstructed. In the kitchen, mount near the kitchen exit — not directly above or beside the stove, where you would have to reach over a fire to get it. In the garage, near the door to the house. In a workshop or laundry room, near the exit of that space.
NFPA 10 requires monthly visual inspections. The inspection takes about 30 seconds:
- Extinguisher is in its designated location and visible
- Pressure gauge needle is in the green zone
- Safety pin is intact and the tamper seal is unbroken
- No visible physical damage, corrosion, or leakage
- Nozzle is clear and unobstructed
- Operating instructions are readable and facing outward
Annual professional maintenance is also required. A certified technician verifies internal components, recharges if needed, and tags the unit with the inspection date. Non-rechargeable extinguishers — the common store-bought type sold as disposable — must be removed from service 12 years from the manufacture date stamped on the unit, regardless of gauge pressure reading.
A reading in the green zone does not mean the extinguisher works
A pressure gauge showing green confirms the unit is pressurized — it does not confirm the agent inside is still effective, the internal mechanisms are not corroded, or that the nozzle is not obstructed. An extinguisher that has never been professionally serviced and is 15 years old may still show green, and may fail when you pull the trigger. Annual maintenance and the 12-year service interval exist for this reason.
04 — When not to fight a fire
An extinguisher is for small, contained fires you can handle safely. When in doubt, get out.
NFPA fire safety guidance is clear on when to use an extinguisher and when to leave. Use an extinguisher only if all of these are true: the fire is small and has not spread beyond its immediate source; you have a clear escape route behind you; the room is not smoke-filled; you have been trained to use the extinguisher; and you have the right class of extinguisher for the fire.
Get out and call 911 if: the fire is large or growing rapidly; you are unsure what is burning; the room is filling with smoke; you do not have a clear exit route; or fighting the fire would require you to approach closely or reach over the fire. Once you leave, close doors behind you to slow the spread of fire and smoke, and do not go back inside for any reason until emergency personnel confirm it is safe.
A portable household extinguisher has 8 to 30 seconds of discharge. If those seconds do not suppress the fire, you should already be moving toward the exit.
Quick reference
- Class A = ordinary combustibles; Class B = flammable liquids; Class C = live electrical; Class K = high-temp cooking oils
- ABC dry chemical extinguisher covers A, B, and C fires; adequate for most home use
- PASS: Pull pin → Aim at base of fire → Squeeze handle → Sweep side to side
- Aim at the base, not the flames — you are suppressing the fuel, not the visible fire
- Placement: near room exit, 3.5–5 feet high, visible, unobstructed; kitchen near exit, not above the stove
- Monthly: check location, gauge (green), pin, seal, no damage
- Non-rechargeable units: remove from service 12 years from manufacture date
- Do not fight a fire if it is large, growing, smoke-filled, or your exit is blocked — get out and call 911
Primary sources
- NFPA 10 — Standard for Portable Fire Extinguishers (via InspectTrack): Classes A, B, C, D, K defined; PASS technique; monthly visual inspections required (Sec. 7.2); annual professional maintenance; non-rechargeable extinguishers removed from service 12 years from manufacture date.
- USFireDept — Fire Extinguisher Types: ABC dry chemical for residential use; Class K required for commercial kitchens with cooking oil fires; NFPA home placement: kitchen near exit (not above stove), garage, each level; 8–30 seconds discharge time; monthly inspection items.