What Are Class C Fire Extinguishers and How Do They Work?
Fires can happen anytime, especially where electricity is used. When an electrical fire starts, using the wrong type of extinguisher can make things worse. This is where Class C fire extinguishers play an important role. They are specially designed to fight fires involving electrical equipment and wiring.
What Is a Class C Fire?
To understand Class C fire extinguishers, we must first understand what a Class C fire is.
A Class C fire is one that involves energized electrical equipment. This includes items like:
- Computers and servers
- Circuit breakers and fuse boxes
- Electric panels
- Appliances and motors
- Electrical wiring and outlets
What makes Class C fires dangerous is the presence of live electricity. If the power is still on, using water or foam-based extinguishers can cause electric shock. That’s why you need a fire extinguisher specifically designed for electrical fires.
What Are Class C Fire Extinguishers?
Class C fire extinguishers are made to safely put out fires that start in electrical equipment. They use non-conductive agents that do not carry electricity. This allows the user to fight the fire without the risk of being shocked.
These extinguishers are usually multi-purpose dry chemical types. Most of them are labeled as ABC extinguishers, meaning they can fight Class A (ordinary combustibles), Class B (flammable liquids), and Class C (electrical) fires.
What’s Inside a Class C Fire Extinguisher?
There are a few types of extinguishing agents used in Class C fire extinguishers:
1. Dry Chemical (Monoammonium Phosphate)
This is the most common type. It smothers the fire by interrupting the chemical reaction. It is safe for electrical fires because it does not conduct electricity.
2. Carbon Dioxide (CO₂)
CO₂ extinguishers work by displacing oxygen around the fire. Since CO₂ is a gas and does not leave any residue, it’s great for sensitive equipment like computers. It also does not conduct electricity.
3. Clean Agents (Halotron, FE-36)
Clean agent extinguishers are ideal for places with electronics, such as data centers. They leave no residue and are safe for use on energized equipment.
How Do Class C Fire Extinguishers Work?
Class C extinguishers work in one or more of the following ways:
– Cooling the Fire
Some extinguishers reduce the temperature of the fire, making it easier to control. However, most cooling-based methods are not used for electrical fires due to the risk of shock.
– Removing Oxygen
CO₂ and some clean agents remove oxygen from the area around the fire. Without oxygen, the fire can’t burn.
– Interrupting the Chemical Reaction
Dry chemical extinguishers stop the fire by interrupting the chain reaction in the flame.
Where Are Class C Fire Extinguishers Needed?
Class C extinguishers are commonly found in areas with a high use of electrical equipment. Some examples include:
- Offices
With computers, printers, and power strips, electrical fires are a real risk. - Data Centers
Sensitive equipment makes clean agent or CO₂ extinguishers a good choice. - Manufacturing Plants
Machinery and control panels can catch fire due to short circuits. - Schools and Colleges
Labs and computer rooms should have Class C extinguishers. - Hospitals
Medical devices and electrical beds require special fire safety measures.
Important Safety Tips When Using Class C Fire Extinguishers
Fighting an electrical fire requires caution. Here are some key safety tips:
1. Do Not Use Water-Based Extinguishers
Water can cause electrical shock or spread the fire. Never use a water-based extinguisher on electrical fires.
2. Disconnect Power If Safe
If possible, turn off the power source before using the extinguisher. Once the power is off, the fire is no longer Class C. It may become a Class A or B fire.
3. Stand at a Safe Distance
Start using the extinguisher from a safe distance. Most extinguishers have a range of 6 to 10 feet.
4. Use the PASS Technique
- P – Pull the pin
- A – Aim the nozzle
- S – Squeeze the handle
- S – Sweep side to side at the base of the fire
Class C Fire Extinguisher Labels and Color Codes
Most fire extinguishers have clear labeling to show the classes of fire they can fight. Look for the Class C symbol, which usually shows an electric plug and socket.
Color codes may vary by region, but typically:
- Dry Chemical Extinguishers – Red with a white label
- CO₂ Extinguishers – Red with a black label
- Clean Agent Extinguishers – Green or white with appropriate labeling
Always read the label to confirm the fire class it covers.
Maintenance and Inspection of Class C Fire Extinguishers
Like any safety device, regular inspection and maintenance are important. Follow these guidelines:
– Monthly Checks
Make sure the extinguisher is in place, the pressure gauge is in the green zone, and there are no damages.
– Annual Servicing
A certified technician should inspect and service the extinguisher every year.
– Hydrostatic Testing
This checks the cylinder’s integrity and is usually done every 5 to 12 years depending on the type.
– Replace After Use
Even if the extinguisher is only partially used, it must be refilled or replaced immediately.
What to Do After an Electrical Fire
Once the fire is under control, take these steps:
- Ventilate the Area – Open windows or use exhaust fans if safe to do so.
- Report the Incident – Inform your safety officer or local fire department.
- Inspect Equipment – Damaged electrical equipment should not be reused.
- Get Professional Help – Have an electrician check the system before restoring power.
- Replace the Fire Extinguisher – Make sure your fire protection is ready for next time.
Final Thoughts
Class C fire extinguishers are a crucial part of fire safety in any location that uses electricity. Understanding how they work and where to use them can help you respond quickly and safely in an emergency.
By choosing the right type of Class C extinguisher—whether dry chemical, CO₂, or clean agent—you can protect your people, property, and equipment from dangerous electrical fires. Regular maintenance and proper training are also key to effective fire safety..
