How does temperature affect the pressure rating of PVC pipe?
PVC pipe is pressure rated at 73° F (23° C). As the temperature drops below 73° F the pressure capacity increases and is usually considered an additional safety factor and not taken into account. However, as the temperature increases above 73° F, the pressure capacity of PVC pipe decreases and the pressure capacity must be de-rated. Following is a pressure de-rating chart for PVC pipe. To calculate the new pressure rating, multiply the working temperature by the de-rating factor. For example, pipe rated at 150 psi at 110° F would have a new pressure capacity of 75 psi (150 x 0.50 = 75).
