subject: Water Fire Extinguishers - Cheap and Versatile [print this page] Water Fire Extinguishers - Cheap and Versatile
The widely used and well known water fire extinguisher is a common sight nowadays and for good reason.
There are a couple of different types of water fire extinguisher but they both extinguish fires by removing the same element of the fire triangle, heat.
The high specific heat capacity of water makes it great for removing or transferring heat.
That's the reason it's used in many heating and cooling systems, in businesses, machinery, homes and vehicles.
This quality also makes it great for removing heat from a fire in order to extinguish it quickly.
Air Pressurized Water Fire Extinguishers
As the name suggests, air pressurized water (APW) extinguishers use pressurized air to propel the extinguishing agent (water in this case) towards the fire.
APW fire extinguishers are relatively cheap and after a fire has been extinguished the water is relatively easy to clean up.
In many cases most of it has probably dried already making the cleanup effort even easier.
Water fire extinguishers are usually painted solid red as this is the colour code for water.
Water Mist Fire Extinguishers
Another variation on the water fire extinguisher uses a fine mist rather than a jet of water.
They use a fine misting nozzle to break up the stream of water so that it's no longer capable of conducting electricity back to the user.
The deionized water is extremely safe and doesn't contaminate it's surroundings. This makes it ideal for use in hospitals.
this type of water fire extinguisher is also painted red in Europe but in the US they're often white.
Additives Used in Water Fire Extinguishers
Wetting agents are sometimes used in water extinguishers. These are detergent based and are used to break up the surface tension of the water.
This helps the water to penetrate the organic material (paper, wood or cloth for example) which is on fire.
Antifreeze is also sometimes added to the water. This is useful when using water based extinguishers in cold conditions.
Antifreeze will lower the freezing point of the water to enable it to be effective for longer in colder climates.
It doesn't have any noticeable adverse effects on the extinguishing capabilities either.
Water based extinguishers are most effective on Class A fires.
We should remember that water fire extinguishers of any variation should not be used on live electrical equipment.
