How to calc force from natural gas?

[doug12345]

Hi, I'm looking for some help in calculating the amount of force from natural gas exploding. Part of the problem is that it causes a wall from a house to fail first. Area of wall 875 SF. Wall depth .25 ft. I was going to assume the whole wall to be the boundry conditions for the volume that gas can fill. (V=219 CF)

The explosive limits of the gas can be 4%-15% of volume. (Vgas=8.76 to 32.85 CF)

Then from wikipedia I found 1 CF gas = 1030 BTU, 1 BTU = 780 ft*lbf (ft-lbs-force)
Next 8.76*(1030)*(780)= 7037784 ft*lbf to 26391690 ft*lbf

Is it then possible to divide the 7037784 ft*lbf by the length of the wall to obtain a distributed load in lb/ft? Am I even approaching this problem correctly?

Thanks

 

[Lojzek]

A better approach would be:

1. Calculate the energy of the gas.
2. Divide it by mass of the air inside the room*specific heat if the air
to get the increase of temperature.
3. Use ideal gas equation to calculate the change of pressure (p2/p1=T2/T1).