RE: [PipingDesign] How is Tensile Strength Established by Tube Spec?

From: <Ken>
Date: Tue Jan 15 2008 - 07:45:00 EST

I usually use listed material, but in this case the client has specified 316L tube to ASTM A 270 (larger sizes) or A 269 (smaller sizes), which is a common ASTM spec for biopharm piping. A 269 is listed, but A 270 is not. So, as Khaled Mahmoud noted, I was trying to follow the requirements of Para. 323.1.2 to qualify the material. But I couldn't trace back how the mechanical properties were being imposed in the manufacture of the tubing.

Since the A 270 standard meets the rest of the requirements of Para. 323.1.2, what I understand from Para. 323.1.2 and the input from Chris and Khaled is that the purchase specification for the tubing must, additionally, include the mechanical properties.

So, I think either the purchase spec must state minimum Tensile Strength and minimum Yield Strength in accordance with specific test methods (e.g. ASTM A 370), or the Supplementary Requirements to A 270, which does state Tensile and Yield Strength requirements, must be specified. Then the allowable stresses in accordance with Para. 302.3 can be determined.

However, all of this still leaves me a bit uneasy, because just specifying the tensile and yield properties does not seem enough to define the material. Would not such properties such as elongation and hardness also have to be specified?

I am grateful for the input, but it seems best that I discuss all of this with a tubing manufacturer and see if I can banish my uneasiness.

Ken A. Nisly-Nagele, P.E.
Project Engineer, Mechanical
Applied Engineering Services, Inc.
9100 Keystone Crossing, STE 200
Indianapolis, IN 46240


From: PipingDesign@yahoogroups.com [mailto:PipingDesign@yahoogroups.com] On Behalf Of Christopher Wright
Sent: Monday, January 14, 2008 6:40 PM
To: PipingDesign@yahoogroups.com
Subject: Re: [PipingDesign] How is Tensile Strength Established by Tube Spec?

On Jan 14, 2008, at 2:52 PM, M. Engineer wrote:

> Per Para. 323.1.2 of ASME B31.3, unlisted materials
> may be used if "they confirm to a published
> specification covering chemistry, physical and
> mechanical properties,

That's the language. No mechanical properties, no compliance

Christopher Wright P.E. |"They couldn't hit an elephant at chrisw@skypoint.com <mailto:chrisw%40skypoint.com> | this distance" (last words of Gen.

.......................................| John Sedgwick, Spotsylvania
1864)
http://www.skypoint.com/~chrisw/ <http://www.skypoint.com/~chrisw/>

[Non-text portions of this message have been removed] Received on Tue Jan 15 07:45:00 2008

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