How to Choose and Use a Home Fire Extinguisher
For most homes, the U.S. Fire Administration (USFA) points to a multipurpose extinguisher labeled "B-C" or "A-B-C", and Ready.gov says an ABC type is the minimum. The label's letters give the fire type and its numbers give the capacity. USFA also lists six questions to answer before you use one.
1. The fire classes on the label
USFA describes five primary types of extinguishers, each matched to a kind of fire:
| Class | Fire it is meant for | Where USFA says it is found |
|---|---|---|
| A | Ordinary materials such as cloth, wood, and paper | Homes and businesses |
| B | Combustible and flammable liquids such as grease, gasoline, oil, and oil-based paints | Homes and businesses |
| C | Electrical equipment plugged into an outlet; the agent does not conduct electricity | Homes and businesses |
| D | Flammable metals | Factories |
| K | Vegetable oils, animal oils, and fats in cooking appliances | Commercial kitchens |
For a house, the practical answer is a multipurpose unit. USFA notes that extinguishers labeled "B-C" or "A-B-C" can be used on most types of home fires, and that most home improvement stores carry multipurpose models covering Class A through Class C. Ready.gov says to have at least one up-to-date extinguisher, with an ABC type at minimum.
2. How to read the numbers
The letters tell you the fire type. The numbers in front of them tell you capacity. According to USFA:
- The number before A is a multiple of 1.25 gallons of water.
- The number before B is a multiple of the area, in square feet, of fire it can put out.
- C has no number. It only means the agent is safe on electrical fires.
USFA's own example is a 1A:10B:C unit. That provides the equivalent of 1.25 gallons of water on a Class A fire, can extinguish a Class B fire up to 10 square feet, and can be used on Class C fires.
Applying USFA's rule to two other labels (these are my arithmetic from USFA's rule, not USFA examples):
| Label | Class A equivalent | Class B coverage |
|---|---|---|
| 1-A:10-B:C | 1 x 1.25 = 1.25 gallons of water | Up to 10 sq ft |
| 2-A:10-B:C | 2 x 1.25 = 2.5 gallons of water | Up to 10 sq ft |
| 3-A:40-B:C | 3 x 1.25 = 3.75 gallons of water | Up to 40 sq ft |
Bigger numbers mean more fire-fighting capacity, but also a heavier cylinder. USFA recommends choosing the largest extinguisher you can safely and comfortably operate. Also look for a "UL Listed" or "ULC Listed" label, which USFA says shows the unit is certified by a nationally recognized testing laboratory.
3. Decide first: fight it or get out
An extinguisher is for a small fire, not a room on fire. USFA suggests asking these questions before you pull the pin:
- Have you alerted others in the building that there is a fire?
- Has someone called the fire department?
- Are you physically able to use an extinguisher? USFA says young children and older adults should not.
- Is the fire small and contained to a single object or surface, like a pan or a wastebasket?
- Are you safe from the fire's toxic smoke?
- Do you have a clear escape route?
Use the extinguisher only if every answer is yes. If you are unsure, USFA's direction is to alert others, leave the building, and call 911 from a mobile or neighbor's phone.
Settle the escape-route question before a project starts: store the extinguisher where you can reach it without crossing the work area.
4. How to use it: PASS
USFA teaches the word PASS:
- Pull the pin. Hold the extinguisher with the nozzle pointing away from you and release the locking mechanism.
- Aim low, at the base of the fire, not the flames.
- Squeeze the lever slowly and evenly.
- Sweep the nozzle from side to side.
USFA says fire departments can help with extinguisher training. Ready.gov says USFA advises using an extinguisher only if you have been trained in its proper use and maintenance, and suggests contacting your local fire department about training.
5. Where to keep it
Ready.gov says everyone in the household should know where the extinguisher is kept and how to use it. USFA's maintenance list starts with easy access: nothing should block or limit your ability to reach it.
6. Upkeep
USFA lists what to check:
- Access. Nothing in front of it.
- Pressure. Many extinguishers have a gauge showing when pressure is too high or too low.
- Working parts. The can, hose, and nozzle should not be damaged, dented, or rusted.
- Cleanliness. Wipe off dust, oil, or grease.
- Manufacturer guidelines. USFA notes some extinguishers need to be shaken monthly, others need pressure testing every few years, and some can be recharged while others must be replaced when pressure is low.
7. Key takeaways
- For most homes, buy a multipurpose A-B-C extinguisher; Ready.gov calls ABC the minimum.
- The number before A is a multiple of 1.25 gallons of water, and the number before B is square feet of fire, so a 2-A:10-B:C unit equals 2.5 gallons on ordinary combustibles.
- Pick the largest size you can safely and comfortably operate, with a UL or ULC listing.
- Fight a fire only if it is small, contained, someone has called 911, and you have a clear way out; otherwise leave.
- Use PASS: pull, aim low, squeeze, sweep. Check access, gauge, and condition.