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#11
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On Sun, 02 May 2004 16:01:47 GMT, "Jürgen Exner"
wrote: O. Sami Saydjari wrote: I just got my first issue of "Light Plane Maintenance" magazine. I am really enjoying it. In their free book "40 Top Maintenance Tips" (p27), they say "get the Halon extinguisher while they are still legal." Halon has been banned years ago because it is one of the worst chemicals wrt. destroying the ozone layer. It was widely used in the 70s and possibly into the 80s, particularly in computer rooms that might contain lots of personnel. At several installations we had large process control computer rooms That used Halon from large tanks located on a lower floor. It's been a while but I'd guess these tanks might have been as large as 150 gallons. They were connected to the computer rooms through either a 3" or 4" header pipe that had a number of outlets. These outlets did not have fuseable links, or diffusers on them as with water. They were wide open pipes and an extinguisher dump was something you did not want to experience more than once. Although these rooms were large, there weren't *that* large. They were solid and tight, separated from the processes by a "blast wall". I saw a 1 1/2 steel door that had been bent from an extinguisher dump. The door was open about 1/3 of the way when the dump occurred. Had the frame not been set in reinforced concrete it would have blown the door in a spectacular fashion. As I recall, there has been some issue that inhaling Halon can be pretty bad for people's health. There are several "gotchas" with Halon, but "in general you can inhale Halon with no ill effects. It is my understanding that it works differently than other extinguishers by inhibiting the combustion process while still leaving enough Oxygen in the air for survival. Not really. Halon is non-toxic. OTOH although Halon is non-toxic, at high temperatures it can generate some very toxic gases. Really nasty stuff when it is broken down into it's basic constituents. Why is a Halon fire extinguisher a great idea. Because is it is non-toxic, very effective, non-corrosive, non-damaging, doesn't leave a residue, and half a dozen other reasons. To my way of thinking there are about the only safe thing to use in an aircraft. Many have dry chemical extinguishers and using one of those in a confined area is ... quite an experience. It'll leave a taste in your mouth for quite a while, but you shouldn't suffer from acid indigestion for a while be it a standard or Purple K (TM) charge. Also, this might sound dumb, but don't C02 extringuisher work by depriving fires of 0xygen? Plus cooling the fire below the ingnition temperature. It seems to me that in a small aircraft cabin, one might also end up depriving the pilot and crew of oxygen as well. With the airflow through most small aircraft I'm not sure the CO2 extinguisher would be all that effective. Roger Halstead (K8RI & ARRL life member) (N833R, S# CD-2 Worlds oldest Debonair) www.rogerhalstead.com Only a concern for prolonged exposure. Perhaps, one can survive long enough to put out the fire and then open the air vents?! Normal ventilation would probably even be enough. jue |
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G.R. Patterson III wrote:
"Jürgen Exner" wrote: Halon has been banned years ago because it is one of the worst chemicals wrt. destroying the ozone layer. In the Americas, only the manufacture is banned. There's a small industry recycling the stuff from old systems, and extinguishers are still available and legal to own. How come this doesn't surprise me? From what I've read, possession is banned in the EU. AFAIK production and sales are illegal. But you don't have to turn in your old extinguisher. jue |
#13
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Roger Halstead wrote:
snip : With the airflow through most small aircraft I'm not sure the CO2 : extinguisher would be all that effective. I was in the engine room of a cargo ship that had a CO2 extinguisher - technically called a "smothering system" activate. Let's just say that you *DO NOT* want to be anywhere near a CO2 system that's been activated. As I recall, two men who couldn't get out were killed. The ship's engines stopped within a minute due to lack of oxygen. I would *NEVER* shoot off a CO2 extinguisher in any kind of confined space. -- Aaron Coolidge |
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On Mon, 03 May 2004 14:19:12 GMT, "Jürgen Exner"
wrote: G.R. Patterson III wrote: "Jürgen Exner" wrote: Halon has been banned years ago because it is one of the worst chemicals wrt. destroying the ozone layer. In the Americas, only the manufacture is banned. There's a small industry recycling the stuff from old systems, and extinguishers are still available and legal to own. How come this doesn't surprise me? So what's to become of your existing stocks? No idea? How come this doesn't surprise me? Don |
#15
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On Mon, 3 May 2004 14:50:56 +0000 (UTC), Aaron Coolidge
wrote: Roger Halstead wrote: snip : With the airflow through most small aircraft I'm not sure the CO2 : extinguisher would be all that effective. I was in the engine room of a cargo ship that had a CO2 extinguisher - I would think the cargo hold would be a lot tighter than the typical small plane where the draft would blow out a match. technically called a "smothering system" activate. Let's just say that you *DO NOT* want to be anywhere near a CO2 system that's been activated. About the only one safe for a confined space is Halon. You'll choke on a dry chemical. The stuff is terrible even in an office, let alone an airplane. As I recall, two men who couldn't get out were killed. The ship's engines stopped within a minute due to lack of oxygen. I would *NEVER* shoot off a CO2 extinguisher in any kind of confined space. I once was able to put my yearly training to use when we had a fire in one of the construction trailers on site. It was Winter and very cold. They had one of the old style Kerosene stoves that were used in many homes. For safety it was set in a metal pan about an inch to inch and a half deep. Thing was probably 4 feet wide, two and a half across and maybe three feet tall. Of course it was located way back at the end of the trailer which made good sense. They had flooded it and when it started it got hot in a hurry, plus there was a good half inch (or more) of kerosene in the pan. The flames were boiling up and then following the ceiling about 20 feet to the door where they were rolling out. I had a 25# dry (Purple-K) extinguisher in each hand. I took a deep breath and went in on my knees. (standing up would not have been conducive to good health. It looked just like the training films with the flames billowing across the ceiling the full length of the trailer). I don't remember how many extinguishers the construction crew had used, but there were a bunch of them on the ground by the door. They had been trying to put out the flames instead of the fire. It took less than the one extinguisher to put out the fire, but that kerosene was boiling hot and was filling the room with fumes... fast. As soon as the flames were out, so was I. :-)) If that sucker relit it was going to be noisy. I was able to hold my breath long enough to go in, put out the fire, and get out. With the heat and fumes, breathing in there would not have been healthy. (It was Hot!) You never, ever use CO2 in any confined space. That would be pressure vessels, holes in the ground, and air tight rooms. They are fine in the normal open office spaces. CO2 does warn you though. It makes you feel like you need to breathe. It is what keys, or triggers the breathing reflex, not the lack of Oxygen. For instance with nitrogen in a confined space you have absolutely no warning. You just go to sleep. Hence the requirement for the complete harness and an outside safety man when entering pressure vessels or holes in the ground. We had a number of underground pumping stations. When I hired in, we'd just go out, open the hatch, go in and check the instruments. By the time I went back to college we couldn't even go in alone. Complete harness and outside backup were minimum. Roger Halstead (K8RI & ARRL life member) (N833R, S# CD-2 Worlds oldest Debonair) www.rogerhalstead.com |
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