Modern Gasworks Practice

792 APPENDIX DISCHARGE OF GAS THROUGH PIPES Pole’s formula :— V = 1350<Z2 vi V s.l. O 5^ II o > i2 ' co r— where V = gas discharged in cubic feet per hour. d = diameter of pipe in inches. p — pressure in inches of water. s = specific gravity of gas (air = 1). I = length of pipe in yards. Pole’s formula gives sufficiently accurate results in cases where gas is supplied under normal low pressure (i.e. up to 6 inches water gauge). For high pressure distribution Unwin’s formula should be used. Unwin’s formula :— 0 = 1,323,250 /p2_p2 p« D5 V Pj X P? X C.S.L. where O = gas discharged in cubic feet per hour. px = initial pressure in Ib. per sq. in. (absolute1). P2 = final „ ,, >: » D = diameter of pipe in feet. S = specific gravity of gas (air = 1). L = length of pipe in feet. C = coefficient of friction = 0-0044