What is CLASS in CLASS 150.......

To all Piping Engg.
I would like to know what does Class denote in Class 150 Flange rating. On referring ANSI B16.5, Table 2, for Class 150, Mat. Grp. 1.1, Temp. 100F, the pressure rating is 285psi.
Then, does it mean that a class 150 flange for that particular group of materials can be utilized upto a pressure of 285 psi. I am a fresher who has just joined a Chemical Manufacturing company. Do clarify this doubt. And also how the term Class came into existence. Regards. Received on Sat May 08 01:44:00 2004