Piping Max Design Temperature Based on Ambient Conditions

Solar heat gain can push the actual pipe wall temperature well above the measured ambient air temperature.

For outdoor piping under direct sun, many oil‑field piping projects add 10‑15 °C margin above the maximum historical ambient temperature to cover solar radiation effect, when complying with ASME B31.3.

It is not only for rigid steel piping, we also pay close attention to this temperature margin for high‑pressure flexible hoses and manifold assemblies working under open‑air hot climate.

It would be risky to only use air temperature without solar correction.

Thank you for your comment. +10 to15C seems to be a generally used number for solar radiation effect. When applied to plastic piping systems this can have a significant effect although all systems need consideration to determine whether any issues need attention.

A good piping equipment supplier will already have a de-rating protocol for each type of pipe on offer. Bear in mind also that the temperature of the wetting agent inside the pipe will also have an effect, as will its insulation and its support method.

This is probably better dealt with by telephone and not CR4.