Class C Fire

Last updated: November 8, 2021

What Does Class C Fire Mean?

A Class C fire is a fire that involves electrical equipment, electrical appliances, or electrical wiring. They are caused by energized electrical elements, such as damaged power cors or overloaded electrical outlets.

It is one of the five classes of fires, along with A, B, D, and K.

Safeopedia Explains Class C Fire

Fires are classified according to which material has caught fire. These classifications help firefighters and other individuals dealing with the situation to respond appropriately and choose the right method for extinguishing the fire.

Portable fire extinguishers are also classified by the type of fires they are designed to extinguish.

If the ignition source is disconnected, the fire is no longer classified as a Class C fire and it can be extinguished and it can be extinguished by more conventional means.

Extinguishing a Class C Fire

The Occupational Safety and Health Administration (OSHA) defines a Class C fire as “a fire involving energized electrical equipment where safety to the employee requires the use of electrically nonconductive extinguishing media.”

As long as the equipment that has caught fire remains connected to a live power source, that power will act as a continuous source of ignition. Until it is removed, the fire will continue to burn and pose an electrocution hazard.

Since water is a good conductor of electricity, water and water-based extinguishers cannot snuff out a Class C fire. In fact, water can spread the fire and even electrocute the person attempting to put it out.

To extinguish a Class C fire, a Class C fire extinguisher should be used. These extinguishers use agents that can separate the elements of the fire triangle (fuel, heat, and oxygen). This allows the fire to be brought under control, even if the source of ignition is still connected.

Using a Fire Extinguisher

Anyone who works in proximity to fire or ignition hazards should be familar with fire extinguishers and how to use them. Most extinguishers operate using the PASS method:

  • P – Pull the pin on the fire extinguisher in order to break the tamper seal
  • A – Aim the fire extinguisher low, with the nozzle pointed at the base of the fire
  • S – Squeeze the handle of the fire extinguisher to release the extinguishing agent
  • S – Sweep the nozzle from side to side while pointing at the base of the fire until it is extinguished

If the fire reignites, repeat the last three steps.

Class C Fire Extinguishers

Fire extinguishers rated as Class C include the following types:

  • Carbon Dioxide (CO2) – Works by suffocating the fire by removing the oxygen, and since CO2 is cold, it removes the heat
  • Dry Chemical – Works by interrupting the chemical reaction taking place in the fire triangle
  • Clean Agent – Uses halon/halocarbon agents and work similarly to dry chemical extinguishers, interrupting the fire triangle's chemical reaction or removing the heat from the fire
  • De-ionized Water Mist – De-ionized water does not conduct electricity and since it is sprayed rather than deployed as a stream, it enhances its cooling and soaking characteristics

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