Thread: Approved horizontal PVC pipe supports

Code Check Complete reports no metals straps directly contacting ABS or PVC, IRC 2605.1. Checked the IRC 2605.1 and it says only "approved" pipe support materials can be used but does not reference a table of approved materials.

In Figure 8, Plastic Pipe Support & Spacing of Code Check Complete, there is a description that states "Wires and plumber's tape not allowed. They fail to resist upward thrust and can cut the piping." Of course there is no IRC or UPC reference in Figure 8.

Anybody got a pointer to a list of "approved pipe support materials for plastic pipe"?

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Bruce,

I'm not sure, so I sent off an e-mail asking the question. I will post the answer here.

Bruce,

Here is the e-mail answer to that question: All metal straps are not prohibited provided to be used on plastic piping - only some are.

~~~~~~~~~~~~~

From: Mike Cudahy [mailto:mikec@cmservnet.com]
Sent: Tuesday, September 15, 2009 7:59 PM
To: codeman@AskCodeMan.com
Subject: RE: metal straps for plastic piping

Sure Jerry,

This is from the PPFA Plumbing Apprentice Training Manual for Plastic Piping Systems.

“Hangers shall be wide enough to avoid deforming the pipe at the point of support. Hangers and straps with sharp or abrasive edges shall not be used. Plastic coated versions of copper hangers are acceptable provided that they allow for movement due to thermal expansion and contraction. However, avoid the use of hangers and supports that contain chemicals which are known plasticizers.”

Also:

“Many hangers designed for metal pipe are suitable for use with PVC. However, the hangers and supports used must provide an adequate load-bearing surface that is smooth and free of rough or sharp edges that could damage the pipe. Typical clevis hangers ranging in width from about ¾-inch in the smallest sizes to more than 1 inch in the larger sizes are usually suitable. Movement caused by the effects of expansion and contraction, as well as movements from pressure fluctuations must be considered to assure proper hanger selection and placement. Hangers and supports used must not compress the pipe, which could prevent movement and cause damage. Also, avoid the use of hangers and supports that contain chemicals which are known plasticizers.”

http://www.ppfahome.org/pdf/Apprentice%20Manual_03.pdf

Basically, in my opinion, you can use some metallic type straps to support plastic pipe – but not ones that will have sharp or abrasive edges. Since thermal expansion will shrink and grow the pipes, you want to “support” and not “rigidly clamp” piping systems. Hangers and supports that have a plastic coating may or may not be suitable – it will depend on what the coating is. Supports made for plastic pipe allow for some movement of the pipe.

Michael Cudahy

PPFA Plastic Pip and Fittings Association
Michael Cudahy
Code and Training Specialist
800 Roosevelt Road, Bldg C, Ste. 312
Glen Ellyn, Illinois 60137
phone (630)858-6540
fax (630) 790-3095
www.ppfa.org
mikec@cmservices.com

www.PPFAhome.org

Thanks Jerry. Nice reference.

Looked at Code Check Complete again. Figure 8 is referenced by the statement on the previous page which references IRC 2605.1 AND UPC 301.1.1 The answer may be in UPC 301.1.1.

I fired off an email to Doug Hansen. Maybe he can provide more details.

Originally Posted by Bruce Ramsey

The answer may be in UPC 301.1.1.

Not unless the UPC is the code which is adopted by your AHJ.

I believe that NC is under the IRC, with amendments.

Originally Posted by Bruce Ramsey

Thanks Jerry. Nice reference.

Looked at Code Check Complete again. Figure 8 is referenced by the statement on the previous page which references IRC 2605.1 AND UPC 301.1.1 The answer may be in UPC 301.1.1.

I fired off an email to Doug Hansen. Maybe he can provide more details.

Douglas is a good source, you might also try Mike Casey he is a co-author of Code Check and is a Master Plumber.
I for one, see nothing wrong with metal plumbing strap.

The contact link at Code Check website goes to Douglas so the email went to him. I am presuming that he will confer with his buddies to figure out why they put in their book that metal plumbers tape cannot be used.

NC is operating under the IRC. I was thinking maybe Code Check is stating no metal straps based on something specific in the UPC.

I am still wondering where I would find a list of "approved materials" in the IRC. Would that be a question for ICC?

Ha, looking back over this post I think I need to use more acronyms and less words.

Below is Douglas Hansens reply regarding the comment in Code Check Complete in the Plumbing section under drainage regarding use of metal straps and reference for "approved materials"

The IRC reference for that item tells us to use approved materials installed to referenced standards, etc. Unfortunately, the IRC does not specifically include the best referenced standard for that item, which is the IAPMO installation standard. They prohibit wire and plumbers tape, and want something that will resist upward thrust. The standard for PVC states, in section 2.5.1: “Hangers and straps shall not compress, distort, cut, or abrade the piping and shall allow free movement of the pipe. Pipe exposed to sharp surfaces shall be protected.” Their concern is that when the pipe moves from thermal expansion or thrust of the contents, the hanger will dig into the pipe rather than allowing it to move relative to the hanger. Out here, we allow plumbers tape supports provided the plumbers tape is first wrapped with duct tape. The IAPMO standards have a similar rule for ABS.

A lot of folks question this particular line in Code Check. It seems to be an unheard of notion in the South and the Midwest, whereas folks in the East and the Western states have always had this rule. Now that IAPMO has an alliance with the World Plumbing Council, I expect to see this spread.

Next, if you contact the manufacturers, they will tell you to use manufactured hangers, not wire or plumbers tape. Using manufactured hangers also makes it easier to get the slope of the pipe correct.

Thanks

Douglas Hansen