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Re: Exploding aerosol cans spreading fires
Posted by: Gerald Hurst (IP Logged)
Date: December 22, 2006 01:27PM

In answer to your question in the last paragraph: Supporting data in most cases would be a positive analysis for the original contents of the ruptured aerosol can at the remote fire location.

The Factory Mutual experiments concentrate on the wrong end of the skunk. Rocketing aerosol cans are inherently interesting but they tend to fly in the opposite direction from the expelled accelerant. When a can blows its bottom, it accelerates away from its liquid content and usually (but not always) becomes an empty vessel before it has moved a foot. Thus the can becomes a relatively poor fire starter compared with the combustible ejecta.

The liquid from a blown-bottom can moves in the opposite direction from the can at a somewhat lower velocity and behaves much like pellets from a shotgun accompanied by a finer mist. In the experiment by Dr. Fox, liquid from the wasp spray can first slams into a board, then bounces 180 degrees back across a 5-foot gap and deposits a large splash on the target blanket – all in the blink of an eye.

If a can is punctured or suffers a broken seam below the liquid level, the liquid will be ejected from the hole by the vapor pressure just as water is ejected from a garden hose or a kid’s squirt gun, without necessarily moving the can at all. The trajectory of the high-velocity stream can carry the liquid to a remote target without depositing any significant quantity in the intervening space. The behavior of liquids expelled under pressure from an orifice has been well understood since the time of Bernoulli.

By far the most important bottom line in this discussion is that ruptured class 2 or class 3 aerosol cans present at a fire scene cannot be eliminated as the source of apparent multiple origins in the absence of additional supporting evidence.



Subject Views Written By Posted
  Exploding aerosol cans spreading fires 2263 John J. Lentini, CFEI 12/16/2006 10:18AM
  Re: Exploding aerosol cans spreading fires 1261 cda 12/16/2006 11:22PM
  Re: Exploding aerosol cans spreading fires 1278 cda 12/16/2006 11:27PM
  Re: Exploding aerosol cans spreading fires 1266 cda 12/16/2006 11:29PM
  Re: Exploding aerosol cans spreading fires 1220 jgmcfps 12/18/2006 10:03AM
  Re: Exploding aerosol cans spreading fires 1200 dahebert 12/18/2006 04:20PM
  Re: Exploding aerosol cans spreading fires 1178 John J. Lentini, CFEI 01/07/2007 09:06AM
  Re: Exploding aerosol cans spreading fires 1003 MIKE 01/12/2007 10:48AM
  Re: Exploding aerosol cans spreading fires 1193 Jim Mazerat 12/19/2006 12:06PM
  Re: Exploding aerosol cans spreading fires 1103 cda 12/20/2006 08:47AM
  Re: Exploding aerosol cans spreading fires 1431 Gerald Hurst 12/20/2006 10:50AM
  Re: Exploding aerosol cans spreading fires 1132 Gerald Hurst 12/20/2006 01:39PM
  Re: Exploding aerosol cans spreading fires 1110 Jim Mazerat 12/20/2006 08:33PM
  Re: Exploding aerosol cans spreading fires 1077 Gerald Hurst 12/21/2006 09:18AM
  Re: Exploding aerosol cans spreading fires 1125 Jim Mazerat 12/21/2006 11:59AM
  Re: Exploding aerosol cans spreading fires 1178 dahebert 12/21/2006 10:10AM
  Re: Exploding aerosol cans spreading fires 1100 Gerald Hurst 12/21/2006 05:32PM
  Re: Exploding aerosol cans spreading fires 1122 Jim Mazerat 12/21/2006 07:02PM
  Re: Exploding aerosol cans spreading fires 1067 Gerald Hurst 12/22/2006 10:49AM
  Re: Exploding aerosol cans spreading fires 1101 Jim Mazerat 12/22/2006 12:04PM
  Re: Exploding aerosol cans spreading fires 1082 Gerald Hurst 12/22/2006 01:27PM
  Re: Exploding aerosol cans spreading fires 1053 Jim Mazerat 12/22/2006 03:45PM
  Re: Exploding aerosol cans spreading fires 982 Jim Mazerat 12/22/2006 12:58PM
  Re: Exploding aerosol cans spreading fires 1043 Gerald Hurst 12/22/2006 01:28PM
  Re: Exploding aerosol cans spreading fires 1148 Anthony Tester 12/19/2006 08:34PM
  Re: Exploding aerosol cans spreading fires 1051 Jim Mazerat 12/20/2006 10:05PM
  Re: Exploding aerosol cans spreading fires 1042 Jim Mazerat 12/21/2006 04:49PM
  Re: Exploding aerosol cans spreading fires 1097 Jim Mazerat 12/23/2006 12:25PM


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