Barlow's Formula Calculator

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

A Little History on Barlow's Formula:

BARLOW, PETER (1776-1862), English writer on pure and applied mathematics, was born at Norwich, England in 1776 and died on the 1st of March 1862 in Kent, England. In 1806 he was appointed mathematical master in the Woolwich Academy, and filled that post for fortyone years. In 1823 he was made a fellow of the Royal Society, and two years later received the Copley medal. He is remembered most for two important contributions:

in 1811, he published An Elementary Investigation of the Theory of Numbers In 1814, he produced a second book, New Mathematical Tables

These soon became known as "Barlow's Tables", and this work gives factors, squares, cubes, square roots, reciprocals and hyperbolic logarithms of all numbers from 1 to 10 000. These tables were considered so accurate and so useful that it has been regularly reprinted ever since. Today, however, they are only of historical interest since they were made completely obsolete by calculators and computers.

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