On Mon, 01 Oct 2001 09:51:37 -0700, Randall wrote:
>Ed Quinn wrote:
>> Halon is heavier than air and
>> displaces the oxygen to prevent fire, but you can't breathe if
>> the gas. I think it was outlawed in Europe as people died from
>> when the halon system in their building went off.
>I think you may have Halon confused with CO2 here. Halon is
>specifically designed to decompose when exposed to the direct
>the fire (900F), it only works right where the fire is burning. The
>that comes out of the extinguisher is (reasonably) safe to breathe,
>does not require a high enough concentration (the target is
>like 2% in enclosed areas) to displace any significant amount of
In the US Navy, at least, there were 2 different Halons used.
Halon 1301 was used for flooding in manned spaces. At the
required concentration it was safe to be in the space (at
least long enough for egress). It was speced for use in
machinery spaces. The other type was Halon 1205. It
was used in unmanned equipment spaces, particularly
electronics enclosures. We used it in the Tomahawk
launchers for fire supression. AFAIK, it is not good to
be in a place where this form of Halon is used.
But, it's all too late, since Halon is a major ODS and
we aren't allowed to use it anymore. I don't know
if it can be easily purchased -- I kind of doubt it.
I believe the chemistry by which halogens react with
high latitude ozone is fairly well understood, and has nothing
to do with low level ozone, which is a pollutant.
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