Safety equipment shouldn't sit in a closet; it should be handy when it is needed. Fire extinguishers save lives and property during kitchen and electrical fires in the home, but they also quash fires in garage workshops, in vehicles or other places outdoors. When purchasing extinguishers, consider not only the type of fire you need it for, but also where you intend to store it.
Extinguishers should be conveniently mounted about four feet off the floor, close to the entrance of the area where they might be needed, so they can be picked up on the way to the fire, rather than be blocked by it. Many of these hazard areas -- vehicle, fuel and machinery storage buildings and shops, and chemical storage sheds -- are outdoors. The Occupational Health and Safety Administration requires workplace extinguishers be located within 50 feet of the hazard area, a good general rule. If extinguishers are kept outside in areas where winter temperatures fall below freezing, their label should indicate that they can tolerate freezing temperatures.
Classes of Extinguishers
Types of fuel dictate the class of extinguisher needed to quench the fire. Class A fires burn paper, wood, insulation, leaves and other common household materials; they use water to rob the fire of heat and literally drown it. Class B extinguishers tackle burning liquids -- gasoline, motor oil, cooking oil and more. Class B extinguishers contain dry chemicals including bicarbonate of soda or carbon dioxide that suffocate the flames. Type C extinguishers use non-conductive dry chemicals and carbon dioxide, which have proven effective in smothering most common fires, including those involving electricity. Extinguishers that use dry chemicals tolerate freezing temperatures. Carbon dioxide, or dry ice, has a very low boiling point; it is packed under pressure at temperatures below freezing in extinguishers. Both dry-chemical and carbon-dioxide fire extinguishers will perform in below-freezing conditions.
Dry chemicals suffocate but do not cool fuel, and carbon dioxide's pressure can scatter fuel such as paper or leaves during use, making water a better alternative for extinguishing some fires. Ethylene glycol and propylene glycol depress water's freezing point, but also thicken at very low temperatures, eventually clogging extinguisher nozzles. Newer freeze-point depressor solutions use salts, which will not thicken as the extinguisher discharges. Type A extinguishers and other liquid-based extinguishers must contain these compounds if they are to be stored where temperatures fall below freezing.
In addition to purchasing extinguishers that are designed for outside storage in freezing temperatures, it is vitally important to take extinguishers in to a certified inspector for annual inspections and re-charging. Even an ABC dry chemical extinguisher, a type recommended for a wide range of household fires, will lose pressure over time. Consult National Association of Fire Equipment Distributors and National Fire Protection Association-certified professionals for your extinguisher's check-ups to confirm that you are storing it safely.