An electrical fire can happen virtually anywhere there is electricity and flammable materials. From lightning strikes to overloaded power strips, electrical fires are a real danger that can become deadly instantly if not appropriately addressed.
Many people wonder what fire extinguisher works on an electrical fire. The following is a rundown of the equipment needed and how to use it.
What You Need to Put Out Electrical Fire
The ideal approach to an electrical fire if it’s small is to smother it. The best tool for larger fires is a CO2 fire extinguisher.
You must be careful not to touch anything that might conduct electricity, but anything that deprives the fire of oxygen will work.
Find the Right Electrical Fire Extinguisher
Rule Out Water
The first rule of fighting an electrical fire is never to use water. Even if you think the fire might be electrical, you should avoid using water to be sure.
Water conducts electricity and can electrocute anyone or anything it touches. It also can spread the electrical charge to other flammable materials, enlarging the fire.
What is an Electrical Fire?
An electrical fire starts whenever electricity touches something flammable. For example, when lightning strikes a tree, the heat of the electricity in a lightning bolt can ignite the wood.
The same principle applies to a building or any other flammable substance that comes in contact with electricity, including frayed wires or overloaded power strips.
Electrical fires are a significant risk in most commercial buildings due to modern electronic equipment. This is why a CO2 (electrical) extinguisher is one of the most commonly required office fire extinguishers.
How Do Electrical Fires Start?
Electrical fires start when the electricity heats flammable substances to the point of ignition. The electricity itself does not ignite.
For instance, the frayed wires that a rodent chewed through can ignite wood used in a building’s walls. An overheated power strip ignites the plastic that encases the strip of outlets. Once started, the fire builds or dies on its own, depending on how much oxygen it can get.
CO2 Fire Extinguishers
CO2 is carbon dioxide. One of its uses is to deprive the fire of the oxygen the fire needs to burn. A CO2 fire extinguisher smothers a fire with a non-conductive gas. The gas is not sticky like foam and does not leave any powdery residue.
CO2 fire extinguishers are the only recommended method of putting out an electrical fire, and they can be used on Class B fires, which are flammable liquids.
What Colour is a CO2 Fire Extinguisher
The best way to recognise a CO2 fire extinguisher is by its markings. All CO2 fire extinguishers are painted bright red with a black panel directly overhead the operating instructions.
Additionally, the nozzle is horn-shaped at the side for smaller models. Models larger than 5kgs have a hose and a horn.
Extinguishers 9kgs or higher are usually mounted to a wheeled trolley as they are too heavy to carry and use safely. Even a 45kg twin cylinder extinguisher is used at airports and offshore. That extinguisher mounts on a moveable platform.
See Also: UK fire extinguisher colour guide – Identifying extinguishers via the colour coding system on their labels.
How CO2 Fire Extinguishers Work
The CO2 in a CO2 fire extinguisher is liquified under 825 pounds per square inch of pressure (55 bar.) Unless the pressure is released, the gas remains in the liquid state.
When the CO2 fire extinguisher is activated, the pressure is released. CO2 gets reduced by a diffuser (the horn) before converting back into gas. As it is released, it rapidly cools the surrounding air.
The CO2 fire extinguisher is designed to work at 3 to 8 feet. The conversion of the CO2 back to gas is so fast that it can cause ice to form on the diffuser. When using the fire extinguisher, be careful not to touch the diffuser when it is activating, or it could freeze your skin.
How CO2 Fights Fires
CO2 is inert in air and does not leave any residue that might harm electrical equipment. It applies dry and often gets stored in proximity to multiple types of electrical equipment.
In many electrical fire situations, a water additive or foam will accompany a CO2 extinguisher to ensure that the fire gets contained and has no chance of spreading.
How To Put Out an Electrical Fire
Because there are several ways a CO2 fire extinguisher can be set up, these instructions will work with the handheld, lighter version extinguisher.
The power source should be cut as soon as the fire is detected. Terminating the power prevents the diffusing of electricity.
When confronted with an electrical fire, pull the safety pin on the handle of the CO2 fire extinguisher. Aim the diffuser at the fire and activate the extinguisher (depress the lever to release the pressurised gas.) Spray in short bursts focused on containing the fire. Do not hold the lever down more than necessary to smother the fire.
Once the fire gets contained, expend the gas on any flare-ups and saturate the area around the fire. Be careful not to get any on the actual source of the electricity. When you have put the fire near the electricity source, use the water additive or foam around the area.
CO2 Extinguisher Facts
The following facts should help you manage the CO2 fire extinguisher as efficiently and effectively as possible.
Do not use CO2 fire extinguishers on Class D fires that involve flammable metals as the gas can blow burning metal over a wide area, enlarging the fire. Volatile metals also react to CO2, causing the fire to spread.
Do not use a CO2 fire extinguisher on paper, cloth, or wood-based fires. It will not work, and you will waste valuable time until you get an effective fire extinguisher. The best fire extinguisher for paper or wood fires is a water based device.
CO2 fire extinguishers do not have a pressure gauge because the gas in the cylinder is pressurised to the point of condensing. The only way to find out if a CO2 extinguisher is full is to weigh it and compare that number to the Gross Weight number stamped into the metal of the cylinder.
Final Thoughts
A CO2 fire extinguisher is the most effective way to fight an electrical fire. If you follow the directions detailed here, you can control most electrical fires.
As always, when confronted with an electrical fire, call the appropriate authorities so that you can ensure the fire is completely put out and safeguard yourself and the people around you.
