Hi John, Just curious what your source is? The same wiki article I got the Hydrogen info from says 1.4% by volume for Gasoline lower explosive limit in air. I can't seem to find a reliable source for the value by mass or for the density of gasoline vapor in order to convert from volume percent to mass percent. Closest I came was Gasoline vapor is about 4 times the density of air so that would put the mass percent for LEL at 5.6%. Sean On Sat, Dec 31, 2011 at 1:34 PM, John Gardner wrote: > By mass ~ 10-15 / 1. > > Stoichiometric is approx 13:1 . > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .