Fire Extinguisher Types & Uses Guide

Table of Contents

Fire extinguishers are the first line of defense you have against fires before emergency personnel can arrive. Extinguishers provide a way for people to prevent further damage and reduce safety risks in case of fire, and it is imperative that maintenance and training are in place so that they can be used effectively.

There are a few things you need to know about extinguishing agents, extinguisher sizes, safety procedures, and more, so you can determine how to equip your facilities effectively. Just as there are different substances that fuel fires, there are different and necessary types of extinguishers designed to put them out. Also note that each kind of extinguisher has different maintenance requirements to keep them operable in times of need. Read on to find out more about what your business and employees can prepare for fire emergencies.

A Brief Overview of Fire Extinguishers

History of Fire Extinguishers

Early fire extinguishers contained an explosive which would quickly distribute a solution. Later models would contain compressed air or water which could be sprayed onto a fire. The current version of the fire extinguisher commonly includes agents which have been engineered to be safe in confined spaces, and there is a variety of agents for handling fires involving grease, electricity, etc. Today’s certified technicians do maintenance on extinguishers according to guidelines put forth by the National Fire Protection Association (NPFA), which publishes standards and codes on building, fire, and electrical safety.

Fire Extinguisher Sizes

The most common portable fire extinguisher size is 5 lb., which is at the lower end of the range of sizes (1.25 lb. to 350 lb.). This size can generally handle fires in averagely sized rooms. Another common size is 10 lb., but keep in mind that some building occupants in an emergency would be more likely to handle a 5-lb extinguisher well. For a large room, consider having two 5-lb extinguishers or one 10-lb extinguisher available.

Classes of Fire Extinguishers

It’s important to be aware of which fire extinguishers your space needs. For some fires, such as those involving electronic transformers or cooking oils, a Class A extinguisher, which contains water-based agents, can actually exacerbate damage. Your facilities may be prone to one or more of these five common classes of fires: A, B, C, D, and K.

Pye-Barker uses four main brands of fire extinguishers: Amerex, Ansul, Badger, and Buckeye.

Class A: Ordinary Combustibles

For fires fueled by paper, wood, fabric, and/or plastics, the Class A extinguisher is the proper choice. An example of a fire emergency involving ordinary combustibles would be a trash fire, which can be caused by dry weather conditions or matches that aren’t put out fully. These extinguishers are commonly seen in hallways, conference rooms, and laundry rooms. Water and monoammonium phosphate are commonly found in this class’s extinguishers.

Class B: Flammable Liquids

Class B fires erupt from flammable liquids, such as gasoline, kerosene, alcohol, batteries containing lithium ions, or petroleum-based paint, or flammable gases like butane, propane, acetylene, and hydrogen. For example, high-pressure fuel pipes found in the generator rooms of marine vessels can experience leaks, making fires a considerable risk. To prevent fires from sucking in more oxygen, the extinguishing method involves smothering and the interruption of chemical reactions. While fighting a Class B fire, make sure to stand at least 6 feet away; flames can spread quickly due to the volatility of the fire’s fuel source.

Class C: Electrical Fires

If your facility involves heavy electronic equipment, servers, motors, or appliances, then Class C fire extinguishers should be on hand. The agents used to fight electrical fires are specifically non-conductive and work to disrupt the flow of fuel and oxygen. Even when wiring is proper and up-to-code, fires of this nature can break out, but do take care to avoid using faulty chargers or overloading your power sources.

Class D: Combustible Metals

Metals like lithium, aluminum, magnesium, sodium, and titanium can indeed be ignited, though at high temperatures. For example, in warehouses, labs, and factories where metal dust is scattered, explosions are possible. Some metals and alloys create high-risk situations when exposed to air or water. Class D fire extinguishers contain dry powder agents which serve to smother these kinds of fires and absorb their heat energy, which can spread rapidly.

Class K: Cooking Oils and Fats

Class K fire extinguishers fight against the kinds of fires that are common in restaurants and other facilities which involve food preparation. Agents like potassium carbonate and potassium acetate work to smother and cool down fuel sources like cooking oil, grease, and vegetable- or animal-based fats.

Types of Fire Extinguishers

The Parts of a Fire Extinguisher

Fire extinguishers, while needing regular inspections and maintenance, are simple to understand. When you pull the safety pin from the top, squeezing the handle releases the contents from the high-pressure canister inside the outer steel cylinder, through the discharge hose or horn, and out the spray nozzle. The pressure gauge indicates whether the internal pressure value is at an acceptable level. Inside water- and carbon dioxide-based extinguishers, activating the handle causes the siphon tube to convert the liquid contents into vapor, which is propelled into the hose. In foam and dry powder extinguishers, compressed gas causes contents to be released.

Chemicals Used in Fire Extinguishers

Common extinguishing agents include water, water mist, carbon dioxide, ABC Powder (primarily made of monoammonium phosphate), and potassium salts. These substances have different features including oxygen displacement and nonconductivity as different types of fires require different amounts of water, water mist, and fire-fighting chemicals.

Water and Foam Extinguishers

Water- and carbon-dioxide-based extinguishers, such as those used for Class A fires, are a reasonable choice for retail stores, offices, and public buildings, and they soak fires fueled by trash, paper, and other common materials. In contrast, water mist and foam extinguishers are used for fires fueled by flammable liquids and gases which require smothering agents.

Dry Chemical Extinguishers (ABC Powder)

Dry chemical extinguishers, also called ABC Dry Chemical, ABC Powder, or monoammonium phosphate extinguishers, are suited for Class A, B, and C fires. They are good to have on hand in businesses, residential spaces, hallways, boats, and cars. Inside these extinguishers is an agent made of monoammonium phosphate powder, which fights the chemical reaction happening in many kinds of fires. However, as the powder is corrosive, it is not ideal for equipment like heavy machinery or aircraft. Additionally, although this kind of extinguisher can put out fires caused by flammable liquids and electronics, it is not suited for Class K fires which are fueled by cooking fats.

Wet Chemical Extinguishers (Class K)

Class K extinguishers contain potassium salts which coat grease- and oil-based fires in a mist, smothering the volatile substances in the air. As such, they are most useful in kitchens and other places where food is prepared. The contents of these extinguishers should be fully deployed to prevent fire from resuming its damage.

Proper Care and Maintenance

Inspection and Testing Intervals

Fire extinguishers must be checked to ensure they are ready to be used in emergencies. Inspection involves making sure they can be reached by anyone in the building: they should be in their proper place, marked with signage or visible, and easy to access. The pressure gauge should be within the acceptable range, and the tamper seal and pin should be in place.

Overall, a certified person must perform an external exam every year, and based on the type of extinguisher, they must internally examine them every 1–6 years. Their tags (or labels) should display the month and year when the maintenance occurred as well as the names of the person and agency conducting the maintenance. Pye-Barker can help you care for any of your rechargeable extinguishers, all of which require internal maintenance.

Recharging and Refilling

The contents of extinguishers must be refilled right after they are used, or if depressurization occurs due to damage. If not used, they are refilled in intervals anywhere from 6–12 years from their manufacture date. Recharging an extinguisher requires depressurizing it, temporarily removing or cleaning certain parts, looking for internal damage, repressurizing it, testing it for leakage, and ensuring its weight is up to code.

Storage Conditions and Locations

Extinguishers can last for years, but they should be checked monthly for signs of damage like denting, cracking, rusting, and improper pressure value. They can be stored outside only if they are secured properly in place (such as in an extinguisher cabinet) and protected from weather conditions that can cause rusting and other damage to occur.

Proper Use of Fire Extinguishers

P.A.S.S. technique (Pull, Aim, Squeeze, Sweep)

Using a fire extinguisher isn’t difficult, but it is essential to remember and review how to use it so that emergencies don’t cause panic. You can remember the steps with the acronym P.A.S.S. First, pull the ring or safety pin out from the top of the extinguisher. Locate the nozzle or hose and aim it at the fire’s base (where the fuel source is located). Then, squeeze the extinguisher handle steadily while maintaining an upright position. Finally, sweep the nozzle/hose left and right to contain the flames as best you can. Stay at least 10 feet away from the fire and never approach it from downwind. Watch for changes in the direction of the wind, and maintain distance from the fire so that you don’t activate it even more.

Safety Precautions

Your safety is the most important factor when it comes to fire emergencies, so your top priority is to be safe and leave the building as soon as possible. Note that because heat and smoke rise, it may be necessary for you to escape by crawling. While extinguishers can help stop or slow a fire, you must make sure that you are confident in your ability to stay safe if you decide to use one, and ultimately it is best to rely on emergency services for dangerous situations.

Before using an extinguisher, make sure that you do the following: notify other occupants of the fire, select someone to call emergency services immediately, ensure the fire is in the early stages and isn’t too widespread to handle, see that you are able to be safe from the smoke, and have a clear path of escape. Avoid using a fire extinguisher if you are incapable of properly operating it, if it doesn’t match the type of fire or is faulty, if you cannot get help or easily escape from the situation, or if the fire is large and unconfined to the place where it began. In these cases, it is best to let the fire be and close the door as you escape to safer conditions.

Code Compliance

If you are a building owner or manager, then you are responsible for communicating safety measures to occupants as well as keeping systems up-to-code. The Authorities Holding Jurisdiction (AHJ) are tasked with enforcing the standards that apply to the equipment you have in place. AHJ groups include zoning boards, local building departments, labor departments, and fire marshals. If you are found to be outside guidelines, then you may be given a citation. In the worst case, lawsuits may be put in place, and further, your business may be shut down. In the name of safety and of best practices, it is imperative that you are on top of code compliance.

Fire Safety Training and Education

Pye-Barker offers training on fire safety including using a fire extinguisher and evacuating. Fires, although unexpected, are distinct possibilities, so it is important to teach employees about the ways to navigate situations that empower them in emergencies and promote their safety.

Positioning of Fire Extinguishers

Fire extinguishers must be located inside or outside your building so that people who can operate them are able to access them in time. They are placed within walking distances (“maximum travel distance”) based on factors such as floor area and hazard level.

Evacuation Procedures

The urgency of a fire emergency makes it necessary for owners, managers, and other responsible parties to have a plan for evacuating all building occupants, paying special mind to those with disabilities who may have a more difficult time getting to safety. Procedures involve providing instruction regarding elevators and stairs, reporting emergencies, conducting fire drills, and of course educating employees and other occupants on plans.

Conclusion

This guide is a general overview of the importance, maintenance procedures, various types and use cases of fire extinguishers, as they are vital tools for reducing fire damage and promoting safety. Pye-Barker is dedicated to protecting people and property from fire emergencies, providing servicing, supplies, and training for emergency situations. We strongly encourage building owners and managers to evaluate their readiness because safety comes first, and it is important to employ systems and plans which prevent the worst from occurring. Fire extinguishers are just one component of keeping you safe, so contact us today to check that you are fully prepared.