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Friday, October 14, 2011

Fire Extinguisher FAQs

Q. What is the proper height to mount a fire extinguisher, as per NFPA 10 guidelines?

A. Extinguishers with a gross weight not exceeding 40 pounds should be installed so that the top of the extinguisher is not more than 5 feet above the floor.

Extinguishers with a gross weight greater than 40 pounds, except wheeled types, should be installed so that the top of the extinguisher is not more than 3 feet above the floor.

In no case can the clearance between the bottom of the extinguisher and the floor be less than 4 inches.

Q. How do you use a portable fire extinguisher and what is the well-known training acronym for proper extinguisher use?

A. Use a portable fire extinguisher by following the P.A.S.S. procedure:
Pull the handle pin on the top of the extinguisher.
Aim the nozzle at the base of the fire and stand approximately 8 to 10 feet from the fire.
Squeeze the extinguisher handle to discharge the extinguishing agent. (Release the handle and the discharge will stop.)
Sweep the nozzle/extinguisher side to side at the base of the fire. After the fire is out, watch/inspect the fire location carefully to ensure it does not re-ignite.
Q. What are the four classes of fires and their respective hazard materials?

Class A: Ordinary combustibles. These can include wood, paper, fabrics, rubber and many plastics.
Class B: Flammable liquids and gases. These can include gasoline, paint, oils, grease, tar, lacquer and other solvents.
Class C: Energized electrical equipment. This can include wiring, motors, generators, panels, switches and appliances.
Class D: Combustible metals and combustible metal alloys.

Q. What does the UL rating for a fire extinguisher indicate?

A. Class A and B fire extinguishers have a numerical rating based on tests conducted by UL (Underwriter’s Laboratories). The UL rating is broken down into Class A and Class B:C ratings. These numerical ratings allow you to compare the relative extinguishing effectiveness of various fire extinguishers.

For example, an extinguisher that is rated 4A:20B:C indicates the following:
The A rating is a water equivalency rating. Each A is equivalent to 1-1/4 gallons of water. 4A=5 gal. of water.
The B:C rating is equivalent to the area (square footage) that, related to the degree of training and experience of the operator, the extinguisher can cover. 20 B:C=20 square feet of coverage.
C indicates it is suitable for use on electrically energized equipment.
When analyzing these ratings, note that there is not a numerical rating for Class C or Class D fires. Class C fires are essentially either a Class A or Class B fire involving energized electrical equipment where the fire extinguishing material must be nonconductive. The fire extinguisher for a Class C fire should be based on the amount of the Class A or Class B component. For extinguisher use on a Class D fire, the relative effectiveness is detailed on the extinguisher nameplate.

Q. How do I determine what size fire extinguisher I need?

A. Portable extinguishers are rated for the size of fire they can handle. This rating appears on the label. An example of such a rating could be, 2A:10B:C. The larger the number(s), the larger the fire the extinguisher can put out. One thing to keep in mind is that higher rated extinguisher models are often heavier—that becomes an important issue when it comes down to properly holding and operating an extinguisher. An extinguisher must be large enough to put out the fire. Most portable extinguishers discharge completely in as few as 8 to 10 seconds. Fire extinguishers are tested by independent laboratories and labeled for the type and size of fire they can extinguish. The applied extinguisher reference/labels can be used as a guide to determining the correct extinguisher for a specific application.

Selection of an extinguisher for a given application depends on the following items:
The nature of the combustible or flammables that present.
The potential severity, including the size, intensity and speed of travel of potential fire.
Effectiveness of the fire extinguisher on a given fire source.
Ease of use of a specific model extinguisher.
Personnel trained in reacting and operating an extinguisher.
The suitability of the extinguisher for a given environment, which can include existing ambient temperature conditions and other surrounding potential atmospheric conditions such as wind, draft and/or presence of vapors or fumes.
Anticipating adverse chemical reactions between the extinguishing agent and the resulting burning material(s).
The health and operational safety issues of extinguisher operators with type of extinguishing agent(s).
The maintenance requirements for certain model extinguishers.
The information below provides additional rating information to assist in determining the appropriate extinguisher for specific applications.

Class A Extinguishers will put out fires in ordinary combustibles, such as wood and paper. The numerical rating for this class of fire extinguisher refers to the amount of water the fire extinguisher holds and the amount of fire it will extinguish.

Class B Extinguishers should be used on fires involving flammable liquids, such as grease, gasoline, oil, etc. The numerical rating for this class of fire extinguisher states the approximate number of square feet of a flammable liquid fire that an average person can expect to extinguish.

Class C Extinguishers are suitable for use on electrically energized fires. This class of fire extinguishers does not have a numerical rating. The presence of the letter “C” indicates that the extinguishing agent is nonconductive.

Class D Extinguishers are designed for use on flammable metals and are often specific for the type of metal in question. There is no picture designator for Class D extinguishers. These extinguishers generally have no rating and are not given a multi-purpose rating for use on other types of fires.

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  1. Fire Extinguishers are used to extinguish fires in emergency.

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  2. Really nice post.Thanks for the sharing.Please keep position about such articles the really spread useful information.I hope it stays updated ..
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