Barlow's Formula

Barlow's Formula - An equation which calculates the relationship of internal pressure to allowable stress, nominal thickness and diameter of pipe.

The formula is: P = (2*S*t) / D, where:
P = internal pressure, psig
S = unit stress, psi
t = nominal wall thickness, in.
D = outside diameter of pipe, in.

Please enter your numerical values for 3 of the following 4 fields:
Do NOT use commas for numbers greater then 999
You MUST click on the Clear Form button to perform additional calculations

P (internal pressure):
psig
S (unit stress):
psi.
t (nominal wall thickness):
in.
D (outside diameter of pipe):
in.