Before ASME came into existance , somewhere in 1919, Taylor Forge had standardised on flanges it made and had calculated the rating to be 150 and 300 lbs per sq in. Later these flange dimensions were adopted as standard by ASME. However much research (and many Ph.Ds) went to material properties and failure of flanges and for the same dimensions the pressure capabilities were increased. Thus 150 lbs flanges could withstand 285 psi now . For interchangebility consideratins dimensions were never changed. Thus we have 150 lb etc but with pressure capabilities varying. In times to come with better material and research this may become more.
This is what I had learnt when I joined the industry and remember having read it in some historical article
Ponnu
GET Mithapur <getuser@tatachemicals.com> wrote:
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.
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[Non-text portions of this message have been removed] Received on Sat May 08 02:08:00 2004
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