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

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: <a href="/group/PipingDesign/post?postID=EW3HKHtKirQDG5_FeOvg-V5cN8AHoYBZBk7s3IOMS6nbs-XQorNDQsGs7JRGeOfSCJF47zjcH7yjozKNu3uZaFlEag">dmcconnico@thermosealinc.com</a>



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

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