Hi, Brian, You were so careful to translate "petrol" into "gasoline" for our Americam brethren, yet totally overlooked your use of a word, which without translation, conjures up an altogether different picture, viz: "...incandescent end of a lit fag. " To us Brits, this means the glowing end of a lit cigarette, but across the puddle, it could be read as the extremely angry end of a burning homosexual. No offense, just a thought and my warped sense of humour. Peter Brian Ellis <[log in to unmask]> 21/10/2002 10:25 PM Sent by: TechNet <[log in to unmask]> Please respond to "TechNet E-Mail Forum."; Please respond to Brian Ellis To: [log in to unmask] cc: (bcc: DUNCAN Peter/Asst Prin Engr/ST Aero/ST Group) Subject: Re: [TN] Flammability Doug Your question is not odd, at all. There is a lot of incomprehension about flammability and flash points and you are quite right to raise the question. The flash point of both these hydrohalogenated solvents and most other hydrohalogenated ones is not measurable by any of the standard ISO methods (open cup, TAG closed cup, Pensky-Martens etc.) under normal conditions. This does not mean they will not burn. They both have lower and higher explosive limits in a fairly narrow range. If you spray them, for example, onto a printed circuit fairly energetically, the rebounding will cause a mist to form and this can explode, if ignited, if the proportions in air are right, at any temperature. To answer your direct question, if you have a bucket of the stuff and you throw a lit ciggy into it, the ciggy will certainly be extinguished and no fire can result, no matter the temperature of the solvent. That does not mean a thing. There is every chance that if you do the same with a bucket of alcohol or even petrol (gasoline for you), it will do the same, even if it is a dozen degrees or more over its flash point. Why? Because there is relatively little energy available in the incandescent end of a lit fag end to heat the vapour sufficiently while it is transiting through the zone where the vapour/air mix is right. Don't try it though, because there are many variables that can upset the equation! :-( The important point that you have missed out is that no one should be smoking anywhere near where any halogenated solvent is deployed, not because of the fire hazard, but simply because he/she can kill him/herself. Inhaling even a very small quantity of solvent vapour through a lit cigarette will fill the lungs with an extremely toxic mix of phosgene (for chlorinated solvents, carbonyl bromide for brominated and so on), hydrohalic acid and carbon monoxide. The first good puff will cause a good high, the second may be even better and the third could easily end in a coffin or, at the best, permanent lung lesions. Just to complete the picture, perhalogenated solvents (e.g., carbon tet and perchloroethylene) do not have explosive limits. In fact, carbon tet used to be used extensively as a sprayable fire extinguisher and it is possible that I may not be alive today if carbon tet had not been used to douse an engine fire in a passenger plane I was in in 1952. (Yeah! I can hear you! Why the hell was that plane equipped with an extinguishing system! :-) ) Perhalogenated solvents can still kill smokers faster than cancer. Please don't hesitate to ask if you need any more info on solvents. Best regards, Brian [log in to unmask] wrote: > Good morning all, > In my quest to ask the oddest question of the day: > > If you threw a lit cigarette into a beaker of either trichloroethylene or > 1,1,1-trichloroethane, would the liquids catch on fire? What would be the > critical parameter in determining this? Flash point? > > Doug Pauls > Advanced Operations Engineering > Rockwell Collins > > --------------------------------------------------- > Technet Mail List provided as a free service by IPC using LISTSERV 1.8e > To unsubscribe, send a message to [log in to unmask] with following text in > the BODY (NOT the subject field): SIGNOFF Technet > To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) > To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest > Search the archives of previous posts at: http://listserv.ipc.org/archives > Please visit IPC web site http://www.ipc.org/html/forum.htm for additional > information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 > ----------------------------------------------------- > > > --------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8e To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ----------------------------------------------------- [This e-mail is confidential and may also be privileged. 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