"Ben Jackson" wrote in message
news:Ttcjc.25047$YP5.1970503@attbi_s02...
In article ,
O. Sami Saydjari wrote:
As I recall, there has been some issue that inhaling Halon can be pretty
bad for people's health. Why is a Halon fire extinguisher a great idea.

Halon is a great alternative to water in indoor environments because
it's non-directional. You can't 'flood' a room with a conventional dry
fire extinguisher, but you CAN flood a room with halon.

Sort of true, but sprinklers are quite capable of flooding a room with
water. The problem is water can cause as much or more damage than the fire
to a lot of expensive things. Then again, for people, being wet is
preferable to being burned.

It's heavier
than air so it fills up the room and smothers the fire. That's the
reason I've been told it's dangerous to inhale -- it will sit in your
lungs.

Yes and no. It is heavier than air, but it does disperse rapidly providing
a relatively constant concentration of Halon in a closed space. At "normal"
concentration levels, it's not hazardous. A properly sized Halon system
will provide a concentration of 6% to 7%. Three to 5% is all that's needed
for it to work. At those levels, there is more than enough oxygen to
breathe without any ill effects (ref: Boyle's Law). The only time there is
a potential problem is when the fire gets really hot before the Halon is
introduced. The high temps can break down the Halon creating some toxic
byproducts. I'd say it's much less of a danger than the smoke from the
fire.

Halon doesn't "smother" a fire. It breaks the chemical reaction. Think of
it as an anti-catalyst. Since it doesn't displace all the oxygen, people
can still breathe. I've been in a computer room that had a Halon system
when it was triggered. When it does, you're supposed to keep the doors
closed so that it can do its magic. The primary risks are 1) Noise - high
pressure gas venting thru little nozzles makes a horribly loud screeching
sound, 2) Limited short-term visibility - that rapidly expanding gas causes
a condensation cloud to form for a few seconds and people trying to move
quickly run into things, and 3) Debris flying everywhere - dirt and other
lightweight items pose a definite eye hazard.

I only deployed a dry extinguisher inside once (small grease fire) and
it was a god awful mess for only a few short bursts.

Done that too. A good whiff that stuff will leave you gagging for hours.
I'll take Halon any day.

Gerry