B31.8 and wphy65

[popi01]

i must calculate a fittings under B31.8
the material is req. as MSS SP WPHY65
THIS FITTING WORK AT 105°C IT MEANS THAT THE CUSTOMER DON'T TAKE IN TO ACCOUNT THE TEMP. DERATING, AND USE A YIELD STRESS OF 448 N/mm (ROOT)
I SUPPOSE THAT IS NOT CORRECT, BUT WHERE I CAN FOUND THIS VALUE ??

 

[grampi1]

B31.4 has a temperature derating table

 

[SJones]

Chapter III states that fittings are to have the same properties as the pipe. Table 841.116A shows that there is no derating for steel pipe up to, and including, 250 deg F. Am I being too simplistic?

Steve Jones
Materials & Corrosion Engineer

http://www.pdo.co.om/pdo/