Path: utzoo!telecom-request Date: Thu, 23 May 91 22:03:16 GMT From: Bob Hale Newsgroups: comp.dcom.telecom Subject: I Was Caught In a Big Halon Discharge Message-ID: Organization: Brooktree Corporation, San Diego Sender: Telecom@eecs.nwu.edu Approved: Telecom@eecs.nwu.edu X-Submissions-To: telecom@eecs.nwu.edu X-Administrivia-To: telecom-request@eecs.nwu.edu X-Telecom-Digest: Volume 11, Issue 398, Message 8 of 10 Lines: 58 In article leichter@lrw.com (Jerry Leichter) writes: [ good discussion about Halon deleted ] > I watched a test of a Halon fire supression system installed at Yale a > number of years ago. The testers remained inside the room as the > system was set off; they seemed quite unconcerned. A decent-sized > Halon system is pretty impressive to watch when fired: It has to get a > sufficient concentration of Halon throughout a room FAST. This > requires that the Halon be forced into the room at high pressure, > creating quite a wind -- all sorts of things go flying. Also, as the > Halon expands rapidly, it undergoes adiabadic cooling, rapidly > dropping the temperature in the room -- so the room instantly fills > with fog. In all, a startling experience if you aren't prepared for > it -- but not in and of itself dangerous. I suspect that the test you witnessed was performed with a dummy substance in the tank rather than Halon. The cost of a tank of Halon suitable for a typical computer room is several thousand dollars for the Halon alone. When my employer had the Halon system tested here they used a dummy material that fogged up the room for a few minutes. The mist is apparently used to decide where the gas flows and how well it covers the intended area. I was an unwitting participant in a real Halon discharge. Two schmucks from a private fire company had been fooling with the fire alarm system all morning and hadn't succeeded in what they were trying to do. I and several others were standing in a newly constructed area, soon to be equipped with a raised floor. Suddenly a noise comparable to a jet aircraft passing overhead at 50 feet altitude started and continued. My first thought was "that jet must be in serious trouble and will probably crash across the street." When the sound didn't change after a couple of seconds my next thought was "it's not a plane, it must be a break in one of the high-pressure gas lines we have here. What kinds of gases do we have in the building? Compressed air - no problem. Dry nitrogen - probably OK, we'll just have to get out of this room soon. Hydrogen - get the **** out of here instantly!!" But then I realized that if it were hydrogen it would explode before I could move more than a couple of paces so I just stayed put. Soon the sound stopped. There was no mist or other visual effect (aside from the trash on the floor being blown all over the room). We remained in the room for a few minutes and then went to the adjacent area which was also physically unaffected. About fifteen minutes later the fire company employees arrived to find out if the Halon had been discharged. The situation was very close to a lynching at that point. This was a fairly small area and the Halon tank only cost about $1800 to refill. None of us suffered any adverse physical effects from it. Bob Hale ...!ucsd!btree!hale 619-535-3234 ...!btree!hale@ucsd.edu