Malleable Iron Fitting Rating

[butelja]

I am looking for more detailed information on the pressure-temperature rating of ANSI B16.3 class 150 malleable iron (A197) fittings. I have information stating that they are rated for 300 PSI from -20°F to 150 °F, and 150 PSI @ 366 °F (saturated steam). What is the maximum service temperature that these are permitted to be used at per B16.3?

 

[scrobe]

In Class 150, the pressure ranges from 300 psi for temp from -20 to 150 F, to 150 psi for temp of 366 F, the temp of 150 psi saturated steam.

In Class 300, it's size dependent, with the max temperature of 550 F resulting in max allowable pressure of 300 psi.

It's very clear in Table 1 of ASME B16.3, page 2.