Flammability 1

[fikayo2004]

Hello all,

Can somebody help me with the origin of this formular

UFLp=UFL+20.6(logP + 1)

Also, is it applicable to all paraffinic hydrocarbon or natural gas only

 

[TD2K]

I'm assuming the UFL is the upper flammability limit, the UFLp is at pressure and P is a pressure term?

Flareman posts on this site and he might know this, you might want to ask him also at his website

http://www.geocities.com/flareman_xs/Home/Welcome_home.html

 

[Flareman]

fikayo2004
The formula you cite probably derives from work published by the Bureau of Mines (Bulletin 627) which included empirical results for Natural Gas.
Two formulae are given
L (vo%) = 4.9 - 0.71 logP (atm)
U (vol%) = 14.1 + 20.4 logP (atm)
(The work reports a standard error of 0.53% for L and 1.51% for U.
Note that these were test results so the formulae represent "best fit" trend. Other hydrocarbons will have different trends because the instability of the molecule is connected with its total energy content including heat of formation and temperature (enthalpy).
The results are reported at 28 degC. Limits get wider as pressure and/or temperature increase.
The original work dates back to 1949 and was connected with natural gas explosions in Coal Mines.

Hope that helps you
David