What type

Fires and the types of extinguishers used to fight them are broken into four categories:

• Paper, wood, fabric and other easily ignited household materials
• Gases and liquids such as gasoline, solvents and grease
• Electrical fires
• Metals such as magnesium and sodium (generally only used in industrial environments)

Many fire extinguishers are designed for use against more than one type of fire. All extinguishers carry a label that states which fire types it is effective against and also numbers that indicate how big a fire it can take on. Thus, an extinguisher marked 5-B, C would be designed to put out a five square foot grease fire as well as an electrical fire, but not a paper fire. On the other hand, one rated 3-A, 10-B, C would be effective against a small paper fire, a larger chemical fire as well as an electrical fire. There is never a numeric rating for the Type C fires, because as soon as you cut power to an electric fire by shutting down a circuit breaker, removing a fuse, or unplugging the device, the fire ceases to be a Type C fire and reverts to either a Type A or a Type B.

You might be tempted to go out and buy large extinguishers rated for all three fire-types, but in most cases, that is not your best option. First, large extinguishers can be hard to handle, especially by younger children and the elderly. Second, many fire extinguishers, especially ones rated for Types A, B and C, contain highly corrosive chemicals. While it's nice to be able to put out a small fire in your home office, you might be less thrilled when you discover that that the chemicals in the extinguisher destroyed the very electronic equipment you were seeking to protect. Most home-use extinguishers contain either halon or various dry chemicals. Halon, a very effective Type B, C extinguisher, is being phased out because of concerns about its effect on the ozone layer. If you have any halon-based fire extinguishers in your home, deploy them near rooms containing computers, stereos and other electronic equipment because halon is effective without being corrosive. However, halon, when combined with fumes from a fire can form toxic fumes, so do not remain in a confined space when halon is used.

For most, a Type B, C extinguisher with non-corrosive chemicals is your best bet. After all, there is nearly always a nearby source of water, which is a very effective Type A extinguisher. However, even with non-corrosive extinguisher chemicals, it is important to clean up all the powder after a discharge because the powder can cause short circuits in electronic equipment.

Where to place

Fire extinguishers should be mounted or placed in a highly visible location 3 1/2 to 5 feet above the floor, out of the reach of small children. They should not be too close to potential fire locations such as stoves or trashcans or a fire may prevent you from getting to the extinguisher. In addition, fire extinguishers are under pressure and should not be located near any heat sources such as radiators or vents. In case of fire, you do not want to move away from avenues of escape in order to reach the extinguisher, so place the extinguisher near or en route to an exit.

Drills and maintenance

Fire extinguishers are only effective at the birth of a fire. Within seconds, or at most, minutes, most fires will outstrip even a large fire extinguisher's dousing capacity. There is no time to read long and often convoluted instructions. In addition, most fire extinguishers discharge for only 8 to 12 seconds. That is not much time if you are confused about how to hold it and where to spray. For this reason, it is important that you conduct drills that give older children and every adult an opportunity to become familiar with extinguishers and their use.

Often the best way to accomplish this is to incorporate the drill into an annual tradition such as Fourth of July, Halloween, or Thanksgiving. After reviewing the extinguisher instructions, start a small fire in a barbecue, fire pit or metal trash can and use an extinguisher to douse it. It can be an exciting and life saving addition to your tradition.

Use the same occasion to make sure that all your extinguishers are visible, clean and fully charged. Most extinguishers have a small gauge or a pressure-test pin. Larger units can be recharged by professional fire extinguisher companies found in the yellow pages. Smaller ones often aren't rechargeable and should be discarded and replaced.

How to use

Always follow the specific instructions on the label that typically include some variation of P.A.S.S.:

• P - Pull the pin.
• A - Aim at the base of the fire.
• S - Squeeze the trigger.
• S - Sweep the spray back and forth, as you approach the shrinking fire.

by David Hollies, reprinted courtesy of HomeAdvisor.com