an Entity references as follows:
Barlow's formula (called "Kesselformel" in German) relates the internal pressure that a pipe can withstand to its dimensions and the strength of its material.This approximate formula is named after Peter Barlow, an English mathematician. , where : internal pressure, : allowable stress, : wall thickness, : outside diameter. This formula (DIN 2413) figures prominently in the design of autoclaves and other pressure vessels.