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How to calc force from natural gas?

  1. Mar 27, 2008 #1
    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?

  2. jcsd
  3. Mar 30, 2008 #2
    A better aproach 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).
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