A Primer on Fire Extinguishers

It was at 4,500 feet on a dark night near Purcell, OK, when the rear seat passenger of a Piper Warrior noticed the seat getting warm and the smell of smoke. Very quickly, the passengers found themselves attempting to control an in-flight fire with...


As noted before, the FAA “approves” fire extinguishers based upon their acceptance by the USCG, UL, and FMRC. As the airworthiness certificate of an airplane is only valid if maintained in accordance with FAA-approved maintenance procedures, the UL certification is only valid if the fire extinguisher is maintained in accordance with a recognized inspection and maintenance program. For the USCG, UL, and FMRC that program is called “NFPA 10,” which stands for “National Fire Protection Association Standard No. 10.”

What SAE is to hardware, NFPA is to fire protection; it is a federally recognized standard that is reviewed and changed as fire protection evolves. NFPA 10 is the national authority on hand-held fire extinguisher installation and maintenance, which gets updated every few years as the NFPA deems necessary. Those familiar with NFPA standards will note another standard, NFPA 408, has been developed for aircraft hand-held fire extinguishers. If you look within NFPA 408, you’ll find fire extinguisher maintenance is to be accomplished IAW NFPA 10. For our maintenance discussion, then, we’ll stick with NFPA 10. For the 135 operator, it’s the required book for a 135 certification. According to NFPA, NFPA 10 is due to be revised this fall.

Halon extinguisher maintenance
Since we’re safety conscious, we’ve dispensed with the idea of having any other than a Halon extinguisher and only Halon requirements are discussed here. NFPA 10 covers a wide variety of fire extinguisher types. NFPA 10 is available at any fire safety equipment dealer or may be purchased on the Internet through the NFPA and other sources.

Halon and Halotron are known as “halogenated agents,” addressed within NFPA 10 as requiring inspections separate from other extinguishers. Briefly, NFPA recommends (and the USCG, UL, FMRC require) 30-day, annual, six-year, and 12-year inspections as described below (specific inspection requirements should be followed in NFPA 10):

1. 30-day inspection. The owner checks location, ensures no obstructions to use, and determines gauge pressure is in limits (Ref: NFPA 10, 2007 ed., para. 7.2.2).

2. Annual inspection. The owner does a general physical once-over of the extinguisher to determine if it’s lost pressure (via reading the gauge) or has any obvious damage, like a dent in the bottle (Ref: para. 7.3.2).

3. Six-year internal inspection. A certified facility empties, disassembles, internally inspects, re-assembles, and refills the extinguisher. Halogenated agents, it’s been learned, combine with moisture to create acids that can corrode cylinders internally (Ref: para. 7.3.1.1.2).

4. 12-year hydrostatic test. A certified facility does the six-year inspection, plus pressurizes the tank to proof test its integrity (Ref: para. 8.3.1).

The owner/operator, for a small fee ($5.00 locally), can have any extinguisher inspected for NFPA 10 compliance by dropping by a certified fire equipment business. A trained individual can perform a quick inspection to let you know if your extinguisher is safe to use, what inspections it is due (or will be due), and whether cylinder documentation is proper. Cheap insurance.

Tips on storage and use
Airplanes are generally short on space, so extinguishers sometimes get tucked into places where they become difficult to see and/or get to. The pilot should determine if, indeed, the fire extinguisher location is accessible and ensure it won’t get damaged by things bumping up against it.

A popular location for extinguishers is under the pilot/co-pilot seat; the owner needs to determine if the extinguisher can be quickly removed for use while flying the aircraft. It may look easy to get to standing in the doorway, but see what gyrations you have to go through to get it off the mount and aimed if sitting in the seat. It should also be checked to see that back seat passenger feet, purses, etc., can’t beat on the top of the extinguisher while stowed.

If you’ve familiarized yourself with the extinguisher label, you should have no trouble operating the extinguisher according to the manufacturer’s directions. If the instructions aren’t clear, consult a fire equipment dealer for more information. The wrong time to learn to use an extinguisher is the moment you need it.

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