Fire extinguishers are tested and labeled using an Underwriters Laboratories standard, UL 711. At first glance, the labeling might be confusing, but once you know the code, it is easy to tell at a glance what types of fires the extinguisher is best for and determine its relative power.
Fire extinguishers are characterized by the type of fires they are designed to put out. Class A fire extinguishers work best on ordinary combustible materials such as wood or paper. Class B extinguishers are intended for flammable liquids, such as gasoline or cooking oil. Class C fire extinguishers are for electrical fires. You'll also find Class D fire extinguishers for combustible metals (in factories or laboratories) and Class K fire extinguishers, which are intended for commercial kitchens (to put out cooking grease and fat fires).
Class A and Class B fire extinguisher labels will also have a numerical code before the letter. That number refers to the fire extinguishing potential and, needless to say, the bigger the better. In the case of Class A fire extinguishers, the number refers to the number of gallons of water that the extinguisher holds, or its equivalent in dry fire retardant. For Class B fire extinguishers, the number refers to the how many square feet of flammable liquid the extinguisher can handle.
Although you can find single-purpose fire extinguishers, most homeowners will want a combination fire extinguisher -- one that can fight Class A, B and C fires for the most comprehensive fire protection. For kitchen use, a Class B and C extinguisher (to fight cooking and electrical fires) is a reasonable choice.
The National Fire Protection Association (NFPA) recommends a minimum of one 2-A:10-B:C fire extinguisher on each floor of your house. In a blog post, ConsumerReports.org notes that bigger fire extinguishers can give you more fire protection, but that some larger fire extinguishers can be too large and bulky to handle in an emergency. Experts say that the best plan is to centrally locate a whole-floor fire extinguisher where it can be easily and quickly reached (no more than 40 to 50 feet from any spot), and to supplement that with smaller fire extinguishers where needed and in higher risk areas (such as kitchens).
Even the most powerful portable fire extinguisher will be overmatched by a fire that has begun to spread. In such cases, the most important thing to do is to look first to your safety and the safety of others by conducting an orderly retreat until you are out of harm's way.
However, a portable fire extinguisher can be a life and property saver if used to attack a smaller, still contained blaze. Here are some things that experts say to look for and consider.
Having a fire extinguisher won't help you much when you need it most if you don't also understand how it works and how to use it. PASS is a simple acronym used to describe the four basic steps in using a fire extinguisher:
PULL the pin. All fire extinguishers have a pin at the top that has to be removed before the extinguisher can be used.
AIM at the base of the fire. That's the spot that will do the most good. Never aim at the flame itself.
SQUEEZE the handle. That releases the fire retardant in the extinguisher.
SWEEP from side to side. Again, keep aiming at the base of the fire until it is out. Even then, keep the extinguisher at the ready and your eye on the area in case the fire re-ignites.
In addition, some fire departments offer fire extinguisher training. Check to see if yours is among those.
In 2009, Kidde voluntarily recalled some of its XL-series fire extinguishers because of an improper lubricant that caused them to lose pressure sooner than expected. Full information can be found at the Kidde website. Current Kidde fire extinguishers are unaffected, but older ones should be checked.