Equations Commonly Used for Calculating Gas Pipeline

Pandhandle A

Pandhandle B

Weymouth :

Qb, Flow rate, SCFD
Pb, Base pressure, psia (Psia=Psi+14.73)
Tb, Base temperature, deg R (deg R = deg F+460)
T, G temperature, deg R
Tavg, Average gas termperature, deg R
P1, Inlet pressure, psia
P2, Outlet pressure, psia
G, Gas specific gravity (Gas = 0.6-0.7)
L, Line length, miles
Z, Average gas compressibility (Commonly = 0.835)
D, Pipe inside diameter, in.
h2, Elevation at terminus of line, ft
h1, Elevation at origin of line, ft
Pavg, Average line pressure, psia [Pavg=2/3(P1+P2-((P1xP2)/(P1+P2))]
E, Efficiency factor ( E = 1 for new pipe with no bends, fittings, or pipe diameter changes. E = 0.95 for very good operating conditions, typically through first 12–28 months E = 0.92 for average operating conditions E = 0.85 for unfavorable operating conditions)

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