The pressure ratings given are for water, non-shock, @ 73°F. The following temperature de-rating factors are to be applied to the working pressure ratings (W.P.) listed when operating at elevated temperatures.
Multiply the working pressure rating of the selected pipe at 73°F, by the appropriate de-rating factor to determine the maximum working pressure rating of the pipe at the elevated temperature chosen.
EX: 6" Clear PVC SCH 80 @ 120°F = ?
140 psi x 0.40 = 56 psi max. @ 120°F
THE MAXIMUM SERVICE TEMPERATURE FOR CLEAR PVC IS 140°F.
Solvent cemented joints should be utilized when working at or near maximum temperatures. GF Harvel does not recommend the use of Clear PVC for threaded connections at temperatures above 110°F; use flanged joints, unions, or roll grooved couplings where disassembly is necessary at elevated temperatures.
Threading of Sch 40 Clear PVC pipe is not a recommended practice due to insufficient wall thickness. Thread only Sch 80 or heavier walls. Threading requires a 50% reduction in pressure rating stated for plain end pipe @73°F.
Chemical resistance data should be referenced for proper material selection and possible de-rating when working with fluids other than water.