From 2001 ASME Section I, PG-27 :
There are two formulae provided :
1.) To determine minimum wall thickness (t) given a certain material,
system operating pressure
& temperature, nominal pipe diameter and type of connections.
2.) To determine maximum allowable working pressure ( P ) given a certain
material, system operating
temperature, nominal pipe diameter & thickness and type of connections.
You seem to be a nice guy and you think you want to learn design..........my
suggestion to you is
not to start from here. Sizing wall thickness and determination of maximum
allowable working pressures
are responsibilities of the most Senior Engineers and my advice to young
Engineers is to learn it, but
make sure a Senior Engineer re-check your work. So much responsibilities
comes with making recommendations
based on these formulae. This could make or break an Engineer's future.
Pardon the intensity........my advice to you is to start in a regular
Engineering Class on this specific
subject where you could be under the direct supervision of a knowledgeable
Engineer.
-----Original Message-----
From: tnmngilman [mailto:tnmngilman@yahoo.com]
Sent: Tuesday, March 18, 2003 7:38 AM
To: <a href="/group/PipingDesign/post?postID=9JBBBjJDpawj9tSTtyx7pu3-Y4-bAZ6XH_Sv2ciwkz5y0ahf120RK66br4XvO7PdliH0X6j-ajPAd7TFquIVzlWVn_ZCIUc">PipingDesign@yahoogroups.com</a>
Subject: [PipingDesign] DESIGN
I don't design for a living, so my apologies if this seems like a basic question. I'm trying to determine the first step in design, and it seems to me that the desired operating pressure has to be known before anything else. In looking at the ASME section 1 formula for wall thickness, the two key unknowns are the material and the pressure. If you use 200 psi in the formula with a certain material, then this is the MAWP.
The other question is: Is there an acceptable means to work backward to determine the MAWP? In other words, if MAWP is not known, is it acceptable to rate a pipe at say 200 psi if it has a successful hydrostatic test at 300 psi? By the book it doesn't seem proper to me to work backward, but if there is no documentation or marking on the pipe how is the safe operating pressure determined?
Thank you.
Your use of Yahoo! Groups is subject to <a href="http://docs.yahoo.com/info/terms/">http://docs.yahoo.com/info/terms/</a> Received on Tue Mar 18 10:19:00 2003
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