Powder fire extinguishers are among the most versatile of fire control solutions. These extinguishers work to put out class A and B fires (normal fires and flammable liquids), but also class C fires, which are those involving flammable gases. They are safe for use on electrical fires as well; the powder contained in the extinguisher is non conductive. These extinguishers put out fires by expelling powder on them, which works very well on flammable liquids and gases.
There are many different types of powder extinguishers, but all use powder with nitrogen as the pressurizing agent. The jet of powder has a range of four to seven meters and can discharge for anywhere between six and twenty seconds. The exact type of extinguisher will determine this capacity. Some have controlled discharge, which makes for easier maintenance. A few of the types of powder fire extinguisher available follow.
BC extinguishers work well on liquid and gas fires, but not other types. They are filled with sodium bicarbonate, which leaves sediment. This sediment is mildly corrosive and should be cleaned off as soon as possible. ABC powder fire extinguishers work on A, B and C class fires and use monoammonium phosphate. This yellow powder leaves a residue as well; one which can damage electronics. Try to avoid using these around electrical equipment.
Always read the instructions on your extinguisher and make sure you know how to use it. Don’t let this wait until there is a fire. A powder fire extinguisher is used by pulling the pin, aiming and then pulling the trigger. The powder should be aimed at the base of the flames or any burning liquid by sweeping it from side to side at the base of the fire. If the fire is in a container, aim the powder at the near side of the fire, then use the jet to propel the fire away from you until it is extinguished.
Liquid which is flowing and on fire is a different case. Aim the powder at the base of the flames and then move the jet upwards. If it is an electrical fire you are working on, turn off the current first, Make sure that the air is clear after the fire is extinguished and check the site to make sure it is out – it can reignite, so be ready to use the extinguisher again if this happens.
Powder fire extinguishers should be kept close at hand and easy to find. These extinguishers can be identified by the blue label on the outside of the red extinguisher. Older powder extinguishers might be blue all over. If you have an older model, then have it regularly serviced to make sure it is still in working condition. Be sure to pressure test it as well to make sure that it is still safe to use. Look for the kitemark of approval on new extinguishers, these tell you that the unit has been tested. All sizes of extinguisher, from 1kg to 100kg should be kitemarked.
You should keep powder fire extinguishers around your home or office, near any place where a fire may occur. These extinguishers are great for liquid and gas fires, so keep them near stoves and furnaces, garages and other non-electrical fire hazards. Be careful in using these extinguishers and always be aware of how to use it before you need to. You are under no obligation to fight a fire – if you don’t feel you can handle a fire, leave the area and call the authorities.