On Sun, 23 Dec 2007 10:09:36 +0000, Andy Burns wrote:

Gas burns in air. Too much or too little air and it won't.

With between 5% and 15% gas the mixture explodes.

True but not without a source of ignition, it doesn't do it spontaneously.
Hence venting pipes with the windows open, you are not likely to get
anywhere near the lower concentration limit.

--
Cheers
Dave. pam is missing e-mail