Blog

What Are the 5 Classes of Fires?

February 9, 2024|fsstechnologies

While it can be hard to tell the difference at first glance, different types of fires occur based on the materials that fuel them. Just as you wouldn’t try to put out a grease fire with water, specific ways to extinguish each fire class exist and depend on what sustains it. Some atypical classes of fires are more common in commercial settings, and it’s critical to know each class to accurately identify fires and then use the appropriate fire extinguishers.

The National Fire Protection Association (NFPA) has guidelines for what each fire class includes and identifies what fire extinguishers can be used to put out each class. Here are the NFPA’s different fire classes and each type’s corresponding fire extinguisher.

What is a Class A fire?

A Class A fire occurs with ordinary combustible materials that you’d find in a typical business or residence. Of the five types of fires, these are the most common type and occur more frequently. Because these solids are usually abundant in any commercial or residential setting, they can create and sustain more intense fires that spread and worsen quickly.

Materials that fuel Class A fires include:

  • Wood
  • Cloth
  • Paper
  • Rubber
  • Plastics

Plastics

Because Class A fires often depend on more everyday solid materials, they are usually less complicated to extinguish. Water is a standard liquid used in Class A fire extinguishers, with the occasional additive of other chemicals. Foam, wet or dry chemicals, or clean agents are also used to extinguish Class A fires in environments that would suffer additional damage from water.

What is a Class B fire?

Class B fires rely on combustible and flammable liquids and gases. While they can occur in businesses and industrial settings that often work with these liquids, homes and other residential environments are also susceptible. A Class B fire can burn at most temperatures when exposed to a fire source because of its low flashpoint, and it often spreads quickly and produces thick black smoke.

Substances involved in Class B fires include:

  • Alcohol
  • Gasoline
  • Oil
  • Propane
  • Paint

While water is commonly used to fight fires, water-based extinguishers may be ineffective against Class B fires. Fire extinguishers rated for a Class B fire often contain foam, clean agents like carbon dioxide, or dry chemicals.

What is a Class C fire?

A Class C fire fuels itself on electricity, usually from live energized electrical equipment and other electrical components. They are highly dangerous, especially when someone attempts to extinguish the fire with water. Class C fires often occur in industrial or commercial settings with lots of electrically powered equipment. Still, they can also happen in residences due to faulty wiring or other electrical issues.

Elements that can sustain a Class C fire include:

  • Appliances
  • Machinery
  • Electric tools
  • Wiring Motors

Due to electricity’s dangerous and conductive nature, Class C fires cannot be suppressed with water. Instead, a fire extinguisher with a non-conductive extinguishing agent, like dry chemicals or clean agents, must be used to douse an electrical fire while protecting whoever fights it from being electrocuted.

What is a Class D fire?

Class D fires depend on combustible metals for fuel, so they often occur in laboratories, industrial businesses, and manufacturing facilities. When these materials are handled in processes that result in dust, shavings, or flakes, that can lead to a fire starting and spreading when ignited.

Metals that can fuel a Class D fire include:

  • Magnesium
  • Sodium
  • Lithium
  • Aluminum
  • Titanium

Water and other commonly used extinguishing agents are typically ineffective against Class D fires. Using water to extinguish the flames can make them more intense and dangerous. Instead, an extinguisher that contains dry powder chemicals must be used to subdue a Class D fire.

null

What is a Class K fire?

A Class K fire occurs when grease or cooking-related combustible materials ignite in a kitchen setting, so it’s common in restaurants or commercial-sized kitchens. While they’re more prevalent in commercial settings, Class K fires can happen in residences where grease or other combustible substances catch fire.

Cooking ingredients involved in a Class K fire include:

  • Grease
  • Oil
  • Cooking fat

Because water can worsen them, Class K fires must be treated with wet chemicals to suppress and cool them. Class K fire extinguishers commonly use wet chemical agents that contain potassium or other alkaline mixtures to create a foamy layer that extinguishes fire.

Identifying which fire classes pose the greatest threat to your business is more challenging than it seems, and ensuring you’re equipped with the proper fire extinguishers for each class is another layer of difficulty that puts your employees and customers at risk. With FSS Technologies, you can rest assured knowing your business is prepared for the worst. Our FSS service technicians can assess your building’s fire ratings, develop a comprehensive plan for a fire alarm system, and implement the proper prevention, protection, and suppression elements. Contact us today to get started.

Explore Our Other Blogs

Hero-afterbreaki-min

What to Do After a Break In

No one ever wants to be victimized by a burglar, but the fact is that many will encounter a theft or break-in at some point in their lifetime. A recent study by Bankrate shows that there are over 1 million burglaries in the United States each year, with a new burglary happening approximately every 26…

Continue reading
NFPA-Standards-Hero

What are the NFPA Standards for Commercial Fire Protection?

What is NFPA?  The National Fire Protection Association is a non-profit organization founded in 1896. Working with more than 9,000 volunteer members, the NFPA works to create fair, balanced standards for the health and safety of the general public. The NFPA’s goal is to eliminate death, injury, and property loss caused by fire; therefore, they have developed more than 300 codes and standards for fire…

Continue reading
2019-04_FSSTechnologies_blogs_who-owns-adt_facebook

Who Owns ADT Alarm Systems After Install?

You’ve paid to have an alarm system installed in your home. Do you own the equipment? Most likely, but not yet if you contracted with a big-box home security company like ADT. Payment Plans for Equipment Most people sign up on special offers in which they will pay an installation fee for the equipment, but…

Continue reading
outdoor-security-cameras-Hero-min

What are the Best Outdoor Security Cameras?

When it comes to protecting your home, you need to think about both the indoor and outdoor components of your security system. Security cameras can allow you to see and monitor what is going on, even if you aren’t there in person. Placing cameras outside to protect your home or business requires a bit more…

Continue reading
Hero-hydrant-min

Why Are Fire Hydrants Different Colors?

The eye-catching colors of a fire hydrant are hard to miss, whether you’re walking through a city or driving around a neighborhood. What many don’t realize, however, is that these colors are integral in helping emergency responders identify and assess their available resources when preparing to fight a fire. Fire hydrant colors are distinct to…

Continue reading
8-home-security-tips-Hero-min

8 Home Security Tips

With more than 45 years of experience in the home and business security industry, here are our top eight tips for discouraging intruders and burglars from targeting your home. 1. Create the illusion that someone is at your house. If you are going to be gone for an extended time, leave a light or TV…

Continue reading
Hero-RingDoorbell-min

Ring Doorbell Cons

Video doorbells are a great addition to home security, and Ring is the popular choice for many who prefer wireless security. Although there are some pros to the Ring Doorbell, it has some cons you should be aware of before purchasing from Ring.   Monthly Fee for Storage The cheapest Ring doorbell is $59.99, with…

Continue reading
home-security-system-Hero-min

Cost of Home Security Systems

Getting a security system for your home is a wise investment. While the obvious benefit is protection for your family, home, and belongings, it’s hard to put a price on the peace of mind that comes from knowing that you and your family will have professional help in case of an emergency. Still, you must…

Continue reading
cctv-vs-ip-Hero-min

What is the Difference Between Analog and IP Cameras in a CCTV System?

When you are considering different security systems and potentially implementing surveillance cameras into your home or business, a big question is whether you want IP or analog cameras. Global Market Insights estimates that the IP camera market will be worth more than 20 billion by 2025. With today’s technology both IP and analog systems can be viewed…

Continue reading
HeroWhereSmokeDe-min

Where Should Smoke Detectors Be Placed?

Smoke Detector Placement Fire can spread extremely fast. In just minutes, a building can be fully engulfed in flames. Smoke detectors are critical to give people inside homes and commercial buildings early warnings so they have time to get out. Proper smoke detector placement is also key when it comes to keeping your home or business safe.  Residential Smoke Detector Placements At a minimum, The National Fire Protection…

Continue reading
24h emergency
Secure My Space
chat with us