GPM = gallons per minute

CFS = cubic feet per second

Lb. = pounds

Hr. = hours

BBL = barrel (42 gallons)

Sp.Gr. = specific gravity

H = head in feet

psi = pounds per square inch

In. Hg. = inches of mercury

hv = velocity head in feet

V = velocity in feet per second

g = 32.16 ft/sec2 (acceleration of gravity)

A = area in square inches

I.D. = inside diameter in inches

BHP = brake horsepower

Eff. = pump efficiency expressed as a decimal

Ns = specific speed

N = speed in revolutions per minute

v = peripheral velocity of an impeller in feet per second

D = Impeller in inches

Nc = critical speed

f = shaft deflection in inches

P = total force in pounds

L = bearing span in inches

m = constant usually between 48 and 75 for pump shafts

E = modules of elasticity, psi - 27 to 30 million for steel