One way to calculate flow is to use the equation Q=22.48 x Cv x sqrt{(P1-P2)*P2/T/G} where : Q = flow rate @ 1 atm, 68 deg F, & 36% rel humidity, in scfm Cv=dimensionless flow coefficient P1=upstream pressure in psia P2=downstream pressure in psia T=upstream temperature in deg rankine (usually 528) G=specific gravity of air at one atmosphere, 68 deg F, & 36% rel humidity (usually = 1) If I use P1-P2=1 psi, P2=14.7 psi, T=528, I get a flow of 120,182 SCFM. Times this by 0.01% or 0.0001 the leakage rate would be ~ 12 SCFM. I hope this helps.
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