When to Use a Water Fire Extinguisher

Water fire extinguishers are useful for putting out most types of fires, those fuelled by materials like paper, fabric, wood and other common flammable materials. They are not, however, to be used for fires involving liquids, kitchen fires and flammable gases. But for Class A fires, water is the one of the best ways to put them out. There are several different kinds of fire extinguisher, including those which work with a gas cartridge and others which use water pressure.

Pressurized water fire extinguishers have been with us since the late 1800's. One type, the soda/acid extinguisher was first developed in 1881 and uses the reaction of sulphuric acid and sodium bicarbonate to fire the water. A vial inside of the fire extinguisher was filled with concentrated sulphuric acid, which was broken into a sodium bicarbonate solution. This forces the water out of the canister and onto the fire through the hose.

However, modern fire extinguishers don't work like this. They use a cartridge which is attached to the cylinder, which is filled with pressurized gas - or the entire cylinder is pressurized. Their skill at quashing class A fires is the same regardless of design. If you are using a water fire extinguisher, be sure to hold firmly onto the hose and direct the water at the base of the fire. Do not use a water fire extinguisher on electrical fires or grease fires. This can spread the fire if it is a grease fire and of course, is an electrocution risk in the case of an electrical fire.

Some water fire extinguishers also contain an additive along with the water. This may be another chemical which helps to extinguish fires. Potassium acetate is a common fire - this forms a crust over the fire which prevents it from spreading further. Detergents and other wetting agents are also used to help the water do its job. To prevent further combustion, chemical or physical agents can be employed, depending on the type of fire. An oil/water emulsion with a polymer is useful for type A fires and type K (kitchen) fires. The oil and water combine with the polymer to form a heat absorbent gel. These water fire extinguishers work no matter where into the fire they are sprayed.

When using a water fire extinguisher, you must first pull the pin holding the trigger in place. Then aim the extinguisher and be sure that you have a good grip on the hose. Stand back eight to ten feet from the fire and pull the trigger to discharge the extinguisher. Sweep the stream of water at the base of the fire.

Once you have put out the fire, watch it to be sure it does not reignite. Even if an area appears to be out, don't walk on it. These areas are often still very hot and can reignite. Water extinguishers bear less danger than do other types, which just displace the oxygen. If the fire does not go out or you are not sure if you can put it out yourself, leave immediately!

Water fire extinguishers can be obtained in many different sizes - three, six and nine litre sizes are all common. A large extinguisher, obviously, is capable of putting out larger fires. Fire extinguishers in the UK which are water based are painted a flat signal red with no coloured band present. In other countries, the colour may vary. In the U.S. for example, water fire extinguishers are white or silver.

Your extinguisher should be serviced regularly to ensure that it still has adequate pressure. You should recharge an extinguisher which has been used as soon as possible. These extinguishers should not be kept in the kitchen, as they are not meant for grease fires or near electrical appliances. In areas where ordinary fires may occur though, such as near a fireplace, a water fire extinguisher is a good thing to have.