Selecting a Fire Extinguisher

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Many of you read the post about extinguishing a grease fire. That was the night I learned that not all fire extinguishers are created equal. Fire extinguishers vary in size and type, so make sure you’ve got the right one.

Which Extinguisher to Buy

Most extinguishers have a number associated with how much fire they can put out. I highly recommend an extinguisher larger than 1-A / 10B,C for your home (I explain the naming system below). Also, multi-class extinguishers are better because they can be used for more types of fire. Amazon sells a great 3A / 40B,C dry chemical extinguisher for only $34.99. I do think the smaller extinguishers are good to have in you car, or by your grill. Count it as the backup as they don’t last very long.

Fire Extinguisher Classes

In the Unites States, there are 5 fire extinguisher classes. Each class is based on the fire fuel type. Many extinguishers can be used on more than one type of fire. Double check what types your fire extinguisher is rated for.

Class A

Class A is used to extinguish fires fueled by ordinary, solid combustibles. This includes things like paper, wood, and most plastics. These extinguishers are labeled with a green triangle. Class A extinguishers contain water and the number (i.e. 4-A) indicates the amount of fire it can put out.

Class B

Class B extinguishers are used on flammable liquids and gases like gasoline, kerosene, grease, and oil. These extinguishers have a red square identifier and the numerical rating indicates the approximate number of square feet of fire it can extinguish.

Class C

Class C fires involve electricity or energized electrical equipment such as wiring, appliances, or outlets. These extinguishers are marked with a blue circle. Never attempt to use regular, pressurized water to put out an electric fire. You could be seriously injured by an electrical shock.

Class D

Class D extinguishers are used to extinguish combustible metals like magnesium and sodium. These extinguishers have a yellow star but won’t have an area / amount rating.

Class K

Class K extinguishers are used to put out burning cooking oils and fats. They are commonly found in restaurant kitchens (think K for kitchen). They are identified with a black hexagon and were developed for use with cooking appliances.

Types of Fire Extinguishers

This may sound a little redundant but each extinguisher dispenses some kind of agent to put out the fire. That agent determines which classes it falls into.

Water Extinguisher: Water extinguishers can be used with Class A fires (solid combustibles). These extinguishers are inexpensive, and typically easy to clean up. Pressurized water extinguishers are usually chrome. Never attempt to use a water extinguisher on a grease fire as that will splash and spread the fire. Also, water can provide a path for electricity. So never use water extinguishers for electric fires.

Water Mist Extinguisher: These have similar properties to pressurized water extinguishers except that they can be used on Class C fires (electrical). This is because the misting nozzle doesn’t create a path for the electricity.

Dry Chemical: Dry chemical extinguishers are usually multi-purpose. They contain a compressed extinguishing agent like potassium bicarbonate that prevents a necessary chemical reaction for fire. Dry chemical extinguishers emit this non-flammable agent, covering the fire which can reduce the likelihood of re-ignition. However, take care to clean up after this extinguisher as the agent is mildly corrosive.

Halon: This type of extinguisher contains a gas that also disrupts chemical reactions for fire to take place. Halon extinguishers can put out fires without damaging electrical equipment (great for Class C). Be careful as they have a limited range.

Carbon Dioxide: CO2 extinguishers are best for Class B and Class C fires. They contain highly pressurized, liquid CO2. When the CO2 is released it becomes a gas which cools the surrounding air and smothers the fire.

Extinguisher Maintenance

Extinguishers should be checked regularly. Verify the extinguisher weight (volume) and pressure. Look for signs of corrosion. Use a rubber mallet to hit the bottom of dry-chemical extinguishers. This will “fluff” the powder making sure it is free flowing.

What do you think? What kind of extinguisher do you have?

Image courtesy of The Jamoker