Determining Sight Glass Thickness

A recommended minimum thickness of a window required to withstand a pressure differential can be calculated by the following formula:

T = Glass thickness (inches)

U = Unsupported diameter (inches)

P = Operating pressure (psi)

σ = Allowable stress (psi)

Allowable stress (psi) of commonly used glass

L.J. Star Incorporated • (330) 405-3040 • www.ljstar.com