ASME B31.3: How does fluid temp affect hydrotest pressure?

[Albanach]

I have a 10"/12"/14" Sch 80 900Lb ASTM A-106 Gr. B SMLS process line which as per our company pipe spec has a hydrotest pressure of 18,735 kPa @ 38 deg.c - now the ambient temperature is more likely to be 18-20 deg.c therefore the fluid temp will drop accordingly - how will the drop from 38 deg.c to 20deg.c affect the hydrotest pressure? I know it will drop but is their a relationship for this?

 

[OSIRIS7]

This will not affect the hydrotest itself. There is only one thing you will have to be sure of: the watertemperature must NOT be affecting the pipe material. Too cold water temperature can damage the system while testing by brittle cracking. It is recommended to use fluid temperature above 18ºC to avoid embrittlement.