FYI, temperature extremes shouldn't affect the function of a standard dry
chemical type fire extinguisher that many people keep in thier cars. Dry
chem extinguishers contain the chemical in the form of an ultra-fine powder
and are pressurized with dry air or nitrogen. The only things that can go
wrong are not temperature dependent but include compacting of the powder if
stored in one position for too long, a leaky seal that allows the stored
pressure to bleed off, or a malfunctioning valve. It is recommended that
you have extinguishers inspected annually, but if you don't (honestly, who
does?) then simply invert your extinguisher at least once a year and give it
a few whacks with a rubber mallet to break up and shift the powder inside it
before storing it again in it's holder or bracket.
For a typical car type fire involving the engine compartment, it is my
preference to use a CO2 extinguisher. The fine powder in a dry chem
extinguisher does an admirable job of putting out the fire, but the powder
literally gets everywhere in every nook and cranny and can be corrosive.
CO2 may take a little more effort to put out the fire (it works best in
enclosed spaces) but if you are planning on ever rebuilding the motor after
the fire it won't leave any residue or cause any damage.
Cheers - Jonathan
The temperature won't affect the extinguisher operation, it MAY affect
the valve if it is one of the cheap plastic ones, it may get brittle and
break when you try to use it. If it is a good unit (Kidde, Sentry, Ansul
etc.) it won't have a problem. One thing that should be done is to
inspect and shake the unit at least once a year to keep the powder from
caking in the bottom and to check for leaks.
I asked an Estinguisher Technician awhile back, and I was told the
plastic valved cheapos can be trouble in severe cold. He recommended
a metal valve estinguisher for in car use. Save the plastic valve one
for the shop.
Has anyone ever heard of cases where extinguishers in vehicles have
exploded due to the heat buildup when the vehicle is parked in the
sun? Man that would make one heck of a mess if a dry chem unit went
off inside a closed vehicle. While some of us have trunk space, those
of us that drive open bed pickups or SUVs don't really have a separate
On a similar note, I have seen pictures of aerosol cans that have
literally launced themselves through seat cushions. I wouldn't want
to be in the way of one of those
Having spent 33 years in the fire protection field I have
never heard of such an event occurring. There is a big
difference in the quality of construction of the shell of
the extinguisher as compared to an aerosol container.
Extinguishers are designed and tested to withstand internal
pressures well above their normal operating pressure.
When carried in a vehicle, on a boat, or whatever, they
should be mounted in a proper bracket to prevent them from
becoming a missile in event of an accident and also to
ensure the extinguisher is where its supposed to be when
needed for an emergency. Vehicle brackets are not the same
as the standard plastic/nylon bracket that usually comes
with your average household extinguisher. You may have to
check with a fire equipment supply company to obtain a
proper bracket. Further, I'd suggest you buy your vehicle
extinguisher from such a company as they will answer any of
your questions about how to use the extinguisher and how to
properly locate and mount it in your vehicle.
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