There are many different types of extinguishers, but today I plan to discuss only the ABC extinguisher. They are by far the most versatile and my personal choice.
ABC – This is the multipurpose dry chemical extinguisher. The ABC type is filled with monoammonium phosphate, a yellow powder. The chemical is non-conductive and can be mildly corrosive if moisture is present. In order to avoid corrosion, it is necessary to scrub and thoroughly cleanup the contacted area once the fire is out.
An ABC extinguisher will work on the three most common types of fires (see below)
- Class A extinguishers are for ordinary combustible materials such as paper, wood, cardboard, and most plastics. The numerical rating on these types of extinguishers indicates the amount of fire it can extinguish.
- Class B fires involve flammable or combustible liquids such as gasoline, kerosene, grease and oil. The numerical rating for class B extinguishers indicates the approximate number of square feet of fire it can extinguish.
- Class C fires involve electrical equipment, such as appliances, wiring, circuit breakers and outlets. Never use water to extinguish class C fires – the risk of electrical shock is far too great! Class C extinguishers do not have a numerical rating. The C classification means the extinguishing agent is non-conductive.
When you purchase an extinguisher check to be sure that it is UL listed (Underwriters Laboratory). The extinguisher will also be marked with a rating for example a standard 5lb extinguisher will normally be rated 3-A-40-BC. This tells you how much fire the extinguisher should handle. If these are not shown on the label do not purchase the fire extinguisher, it is probably cheaply made overseas and may not be reliable.
How much fire will your extinguisher handle?
Below you will find tables that show how much wood or flammable liquid the unit should extinguish to obtain their ratings.
To achieve a Class “A” rating, the extinguisher must be capable of putting out the wood crib, wood panel and excelsior (shredded paper) tests. Ratings are based on the size of the material that can be repeatedly extinguished.To achieve a class “B” rating, the extinguisher must repeatedly put out a flaming liquid fire. Ratings are based on the size of the fire.To achieve the Class “C” rating the extinguisher and contents must pass certain electrical conductivity measurements in accordance with UL711 and UL299.
Where to place an extinguisher and how to use it.
Always place your extinguisher near an exit. If it fails to function or is insufficient to extinguish the fire you want an escape route. Be familiar with your extinguisher prior to ever having to use it. Know how to pull the pin to activate the extinguisher.
If you need to extinguish a fire, point the extinguisher at the base of the flames, squeeze the lever sweeping the extinguisher from side to side. If the fire is not put out, get out don’t be a dead hero. If the fire is out, check carefully for hot embers. If you can wet everything down.
By law in most if not all states an extinguisher in a commercial establishment needs to be serviced annually. I don’t know about your home. The reason an extinguisher needs to be serviced is because the powder compacts and settles to the bottom. If this happens you will not get a proper flow of powder.
Fire extinguishers have become so inexpensive, that instead of servicing them every couple of years I buy a new one. I usually don’t throw the old ones away too quickly, but I shake them to try and keep the powder from compacting or forming lumps. But I can’t guaranty that this will work, do it at your own risk. Beware of extinguishers that have been in vehicles. The motion causes the powder to compact quickly.
More on different types of extinguisher in near future.