Fire Extinguisher Safety

It is important to know how fire extinguishers work, how to use them, how to identify which type to use, and how to maintain them before a fire takes place.

When they are used correctly, fire extinguishers can save both lives and property, but many adults do not know how to properly use one. It is important to know how fire extinguishers work, how to use them, how to identify which type to use, and how to maintain them before a fire takes place.

Before Using an Extinguisher

While it is necessary to act quickly in the event of a fire, education also goes a long way in fighting hostile fires. Knowing what to do in an emergency before it happens will help make firefighting quicker and safer:

Pull the alarm – If you see a fire, always activate the fire alarm to alert both the occupants of the building as well as the fire department (call 9-1-1 if your alarm system doesn’t do this automatically).
Plan an escape route – if you plan on fighting the fire, know how to leave the area quickly in case the fire gets out of control. Only fight the fire if you have a clear escape route.
Know how to use the extinguisher – take time to learn how to properly aim, sweep, and extinguish a fire; many offices and companies have annual employee safety trainings which include fire extinguisher exercises.
Assess the size of the fire – fire extinguishers are only meant to put out small, single-location fires; never attempt to put out a large conflagration with a handheld extinguisher.
Determine the fuel source – it is important to know what kind of fire is burning before you use an extinguisher – using the incorrect extinguisher can be extremely dangerous – by spreading the fire or causing flare ups. For example, using a water-based extinguisher can spread an oil fire or electrocute a user fighting an electrical fire, and Carbon Dioxide extinguishers can actually fuel certain types of fires.

Types of Extinguishers

A fire’s fuel source will determine what type of fire extinguisher needs to be used to extinguish it. In the United States, there are five classes of fires as defined by the National Fire Protection Association:

Class A – Common combustibles such as wood, paper, most plastics, rubber, and fabric. Symbols: Triangle with letter A and picture of burning wood/trash can.
Class B – Flammable liquid such as gasoline, oil, paint, and kerosene. Symbols: Square with letter B and picture of burning gasoline jerry can.
Class C – Electrical fires and electrical equipment. Symbols: Circle with letter C and picture of burning electrical plug and socket.
Class D – Combustible metals such as lithium batteries, sodium, magnesium, and potassium. Symbol: Five-Pointed Star with letter D and picture of burning machine gears.
Class K – Cooking oils and fats such as vegetable oils, margarine, butter, animal fats, and grease. Symbol: Hexagon with letter K and picture of pan/pot on fire.

Each class is marked on an extinguisher by both a letter (class letter), and a symbol. Most homes and offices contain multi-purpose “ABC” extinguishers which can be used for those three classes of fire. The contents of fire extinguishers vary depending on the class of fire being put out. Some materials can put out multiple classes of fire, while others are used for only a specific class. These include dry chemicals, foams, Carbon Dioxide, halon gases, compressed water, and pressurized metal based powders. It is important to know what is in your building’s extinguishers so they do not cause more damage than necessary (especially when used around electronic equipment). It is also important you never use the incorrect class of extinguisher as it may exacerbate the fire.

Using an Extinguisher

When using an extinguisher, remember the acronym “PASS”, which stands for, Pull, Aim, Squeeze, and Sweep. Stand between 6 to 8 feet away from the fire and:

Pull the safety pin to release the trigger.
Aim at the base of the fire (where the fuel source is).
Squeeze the trigger continuously until the spraying stops.
Sweep from side to side until the fire extinguisher is empty.

An average size fire extinguisher dispenses its contents within 8 to 10 seconds – if the fire does not disappear, leave the area immediately.

Proper Maintenance

Fire extinguishers need to be routinely checked for adequate pressure and cleanliness.

Make sure there is no visible rust or dents on the extinguisher and the handle/trigger are clean and free of dust and debris.
Fire extinguishers should always be kept in easy to reach, clearly visible (and marked with signage), unobstructed places, evenly distributed among floor plans and throughout multiple floors of a building. Keep in mind the typical hazards located around the building – keep Class K extinguishers near the kitchen, Class C extinguishers near the computer room/server room, and class A extinguishers near the dumpster.
Depending on the type of chemical/gas used, the fire extinguisher will need to undergo hydrostatic pressure testing by a professional on a varying schedule: between 5 years for wet contents, CO2, & foams, and up to 12 for halon gases, dry powders, and dry chemicals.
Extinguishers exposed to elements such as vibrations, extreme heat or cold, or ones stored on vehicles should be inspected/tested more frequently.
Regular maintenance such as visual inspections, cleanings, and pressure checks should be done every month.
In areas with many kids and teenagers, fire extinguishers should be kept in protected cabinets (where glass must be broken or an alarm sounds if opened) to deter vandalism.

While fire extinguishers can be the first line of defense against a fire, they have their limitations. Never use a fire extinguisher without training and only use it to combat small fires. Handheld extinguishers are ineffective against conflagrations, so the best course of action when confronted with a large fire is to leave the area immediately and wait for the fire department from a safe distance. Most importantly, always activate the fire alarm and if for any reason you cannot fight the fire, leave the area at once; you can replace property, but you can’t replace lives.

“Choosing and using fire extinguishers.” U.S. Fire Administration, FEMA, 29 Dec. 2016, www.usfa.fema.gov/prevention/outreach/extinguishers.html . Accessed 10 Mar. 2017.