Date: 12 Oct 2001 08:11:12 -0700 From: swear@blarg.net (Gary W. Swearingen) To: freebsd-chat@FreeBSD.ORG Subject: Re: Use of the UNIX Trademark Message-ID: <s8r8s8sxkf.8s8@localhost.localdomain> In-Reply-To: <20011011210426.D293@blossom.cjclark.org> References: <007701c15216$867d47c0$1401a8c0@tedm.placo.com> <a05101003b7eb12fedac9@[194.78.144.28]> <6xzo6xssir.o6x@localhost.localdomain> <20011011210426.D293@blossom.cjclark.org>
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"Crist J. Clark" <cristjc@earthlink.net> writes: > On Thu, Oct 11, 2001 at 03:47:56PM -0700, Gary W. Swearingen wrote: > > > > Also, I'll bet a tank of compressed air is a lot cheaper than one of > > either Oxygen or Nitrogen. > > I've never seen a commerial cylinder of air. I don't know if you can > buy one. I would think that for the vast majority of applications it > is cheaper to buy an air compressor than to buy cylinders of air. I'm sure that you can buy nearly any gas you want, but maybe its uncommon need outside the SCUBA field would make it no cheaper than O & N. I do remember seeing hugh tanks of liquified air that someone preferred to an air compressor. > > Anyone know if highly compressed air is > > a dangerous fire hazard along the lines of Oxygen (but less so, of > > course)? > > Air is about 80% nitrogen, 20% oxygen. When you compress it, it is > about 80% nitrogen, 20% oxygen, the concentrations don't > change. Making some approximations, the reactivity of the gas is > driven by the partial pressure of oxygen. The partial pressure of > oxygen in air is about 1/5 of that in pure oxygen. Compressed air is > about "five times" less reactive than pure oxygen, whatever that > means. I guess it means that compressed air is a dangerous fire hazard, but less so, at the same pressure. If delivered at 5 times the pressure of pure oxygen it delivers the same amount of oxygen, but will still be less dangerous because of the extinguishing/smothering effect of the other gases (mostly nitrogen). This dangerousness of this will be very rapidly decreased with increasing separation of the combustion and the delivery nozzle. I suppose that this latter effect results in compressed air not having a reputation as a fire hazard. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-chat" in the body of the message
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