The Pipeline Rules of Thumb Handbook uses the equation Q = D^2*P to estimate the flow rate of escaping gas from a pressured line (see link below for excerpt) under standard conditions. Where Q is flow rate in Mcf/hr, D is diameter of the nipple or orifice in inches, and P is the absolute pressure in psi at a near point upstream from the opening. Looking at the equation with respect to units, I see that the right side has an area multiplied by a pressure, which results in a force. in^2 * lbs/in^2 = lbs ..... = Mcf/hr ???? But according to the book, we end up with Mcf/hr...not lbs. Obviously PiplineROT did some sort of approximation and cancellation here that they did not explain, but what is it? How does this make sense? http://books.google.com/books?id=2D...as blown off through a line puncture&f=false"