Re: Why Class 150 ?

From: <jacques>
Date: Sat May 08 2004 - 14:22:00 EDT

Does anyone know where the term "head" used in the pump world originates from?

Jacques

• Original Message ----- From: DAVIS MCCONNICO To: PipingDesign@yahoogroups.com Sent: Friday, May 07, 2004 4:36 PM Subject: [PipingDesign] Why "Class 150" ?

   Ok, all you pipe nerds.

   Here's a dumb question.

   I'm not an engineer, just a gasket salesman. But I enjoy reading this forum    and have enhanced my knowledge thereof. I've asked this for the last few    weeks to all my engineer customers and no one knows.

   Usually when a pipefitter (in the USA) refers to a "150 lb. flange" he means    an ASME B16.5 Class 150 flange. It's amazing how many think the "pressure    rating" of that flange is 150 psig. Obviously, that's not the case. It's    material and temperature dependent. For example, per table 2 of B16.5, a 304    Stainless Class 150 flange has a pressure rating of 235 psig AT 200 deg. F.    But here's my question:

   Why DO they call it a "Class 150" flange?    From whence was the figure "150" derived?

   It's not the weight! It's not the pressure rating! I've even run some    numbers from table 2 and it doesn't even seem to be the AVERAGE! (I ran an    average on the table for the 4 material groups of carbon steel, which is the    highest pressure rated group: 130 psig)

   Here's hoping someone can clear up a long-standing and nagging question.

   -Davis

   Thermoseal Contact Information

       Area Representative:
           Davis McConnico
           South East District Manager
           Thermoseal Inc.
           Pensacola, FL.  32504
           voice: 850 / 477-0960
           fax: 850 / 477-0106
           email: dmcconnico@thermosealinc.com






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[Non-text portions of this message have been removed] Received on Sat May 08 14:22:00 2004