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From: jcmorris@MWUNIX.MITRE.ORG (Joe Morris)
Newsgroups: misc.security
Subject: Re: halon
Message-ID: <9103021947.AA19582@ucbarpa.Berkeley.EDU>
Date: 1 Mar 91 15:07:03 GMT
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Right.  The production of halon (and all flurocarbons) is being phased out
due to the environmental problems it causes.  As a result it is probably a
poor choice for a new installation, although existing halon systems probably
don't need to be converted yet.

There are some problems (long known) with halon; in particular, one of the
flavors (halon 1201, I think) has the disconcerting habit of decomposing
into phosgene gas when exposed to extremely high temperatures.  Other
than this, however, I don't know of any reason to call it 'injurious'.

I just installed a fire protection system in my computer area; we considered
halon but instead went for a water system:

  - sprinkler heads overhead only (considered and rejected underfloor heads)

  - Dry-pipe system is charged only after two zones report smoke and/or
    ionization detection

  - Overhead pipe is supervised with compressed air to detect any leaks or
    broken sprinkler heads

  - Alarm system trips out main power feed and UPS power output 60 seconds
    after overhead system is charged unless abort switch activated.   The
    air handlers are tripped out immediately.

  - And, of course, panic switches to trip out the power and charge the
    overheads immediately.

I'm not exactly ecstatic about having water in an electrical environment but
what we installed seems to be a reasonable compromise.

Joe Morris

(PS: you're looking at protecting UKCC, say hello to Selwyn Zerof for me.)