Hanger Supported by CPVC Pipe Acceptable?

12/6/2022

I am an AHJ and trying to determine if this CPVC/BlazeMaster pipe has the correct hanger arrangement.

I was unable to find anything in the BlazeMaster installation manual. You can see from the photo that the sprinkler branch line hanger is attached to the building steel structural beam.

However the sprinkler drop is supported by a hanger, attached to the branch line, and not to a building structural element.

Is this a correct method of supporting a sprinkler drop?

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12 Comments

Dan Wilder

12/6/2022 06:43:04 am

I've done it with steel using the trapeze tables within NFPA 13 however I cannot find anything as to section modulus or spans for CPVC. This would be a call to the MFG or a request to the installing contractor to provide the engineering backup for this installation.

Due to the flexible nature of CPVC and the much lower spans available for just hanging, this picture/installation would push me to an alternate solution.

Personally, I would have placed an additional hanger within 6" of the upper attachment point of this trapeze hanger, while keeping the standard hanger spacing on the upper line (unless I went down the road of MFG's data for modulus values and such) or just swung the lower arm-over out a couple inches for a clear shot to the deck with a hanger.

Ryan

9/6/2024 07:30:59 am

You can not hang sprinkler pipe from itself. Only a trapeze and that is not a trapeze.

Alex

12/6/2022 07:16:37 am

Hi, as Dan mentioned above, its common with steel but I have never seen it with CPVC. I would simply ask the installing contractor to have the manufacture provide a letter stating the installation is acceptable.

Anthony

12/6/2022 08:07:40 am

Not ok without 'showing your work' if the math works out it would be acceptable. I however doubt that would be the case. That doesn't pass the eyeball test, looks like it would break with that 250lb (me) hanging from it that is required for NFPA-13 hangers.

martin m. link

12/6/2022 08:11:58 am

When in doubt "default" to AHJ
Merry Christmas to all, Happy Holidays and New Year!

James Phifer

12/6/2022 08:19:17 am

The appendix 2016 ed. NFPA 13: A.9.1.1.8.1 - provides the option to support sprinkler piping from other sprinkler piping where the requirements of 9.1.1.2 are met. meaning it must support the weight of the water filled pipe plus 250 lbs, Like Anthony mentioned, I doubt that would support 250 lbs.

Craig Vesely link

12/6/2022 08:21:17 am

Referencing the 2022 edition of NFPA 13, Section A.17.1.3.1 states, "NFPA 13 provides the option to support sprinkler piping from other sprinkler piping where the requirements of 17.1.2 are met." I would use this verbiage to explain the intent of the Technical Committee to the installing contractor.

Glenn Berger

12/6/2022 08:33:51 am

It looks wrong and probably not originally designed this way. I would hoped to have see a pipe hanger for the branch pipe above.

Todd E Wyatt

12/6/2022 08:37:59 am

SHORT ANSWER
Request the listing information for this CPVC installation.

EXPLANATION
2022 NFPA 13 states the following :

17.4.3.4 * Unsupported Lengths.
A.17.4.3.4
Sprinkler piping should be adequately secured to restrict the movement of piping upon sprinkler operation. The reaction forces caused by the flow of water through the sprinkler could result in displacement of the sprinkler, thereby adversely affecting sprinkler discharge. Listed CPVC pipe has specific requirements for piping support to include additional pipe bracing of sprinklers. (See Figure A.17.4.3.4.)

ENHANCED CONTENT
As Figure A.17.4.3.4 illustrates, extending the branch line to the next structural member prevents an excessive cantilever of the piping.

I apoligize that I cannot attach "Figure A.17.4.3.4" to this message.

2022 NFPA 13 also states the following regarding "nonmetalic pipe and tubing" :

7.3.2* Nonmetallic Pipe and Tubing.
7.3.2.1.1
Other types of nonmetallic pipe or tube investigated for suitability in automatic sprinkler installations and listed for this service, including but not limited to CPVC, and differing from that provided in Table 7.3.1.1 shall be permitted where installed in accordance with their listing limitations.
7.3.2.1.2
Manufacturer’s installation instructions shall include its listing limitations.

A.7.3.2
CPVC is a plastic material, and consideration is necessary when other materials or chemicals come in contact with CPVC that can cause degradation of performance of the pipe due to interaction of materials. Other construction materials include but are not limited to materials used in fabrication of the sprinkler system, additives to water supplies, cable, and wiring, and certain insecticides and fungicides. Compliance with 7.3.2 combined with following the manufacturer’s guidance on installation and compatible materials will help prevent premature performance degradation of non-metallic piping. Mechanical stress caused by hanging methods or bending on non-metallic piping beyond the manufacturers recommended limitations can cause stress failure over time and should be avoided.

Other types of pipe and tube that have been investigated and listed for sprinkler applications include thermoplastic pipe and fittings. While these products can offer advantages, such as ease of handling and installation, cost-effectiveness, reduction of friction losses, and improved corrosion resistance, it is important to recognize that they also have limitations that are to be considered by those contemplating their use or acceptance.

With respect to thermoplastic pipe and fittings, exposure of such piping to elevated temperatures in excess of that for which it has been listed can result in distortion or failure. Accordingly, care must be exercised when locating such systems to ensure that the ambient temperature, including seasonal variations, does not exceed the rated value.

The upper service temperature limit of currently listed CPVC sprinkler pipe is 150°F (65.5°C) at 175 psi (12.1 bar).

Not all pipe or tube made to ASTM F442, Standard Specification for Chlorinated Poly (Vinyl Chloride) (CPVC) Plastic Pipe (SDR-PR), is listed for fire sprinkler service. Listed pipe is identified by the logo of the listing agency.

Not all fittings made to ASTM F437, Standard Specification for Threaded Chlorinated Poly (Vinyl Chloride) (CPVC) Plastic Pipe Fittings, Schedule 80, ASTM F438, Standard Specification for Socket-Type Chlorinated Poly (Vinyl Chloride) (CPVC) Plastic Pipe Fittings, Schedule 40, and ASTM F439, Standard Specification for Socket-Type Chlorinated Poly (Vinyl Chloride) (CPVC) Plastic Pipe Fittings, Schedule 80, as described in 7.4.4, are listed for fire sprinkler service. Listed fittings are identified by the logo of the listing agency.

Consideration must also be given to the possibility of exposure of the piping to elevated temperatures during a fire. The survival of thermoplastic piping under fire conditions is primarily due to the cooling effect of the discharge from the sprinklers it serves. As this discharge might not occur simultaneously with the rise in ambient temperature and, under some circumstances, can be delayed for periods beyond the tolerance of the piping, protection in the form of a fire-resistant membrane is generally required. (Some listings do provide for the use of exposed piping in conjunction with residential or quick-response sprinklers, but only under specific, limited installation criteria.)

Where protection is required, it is described in the listing information for each individual product, and the requirements given must be followed. It is equally important that such protection must be maintained. Removal of, for example, one or more panels in a lay-in ceiling can expose piping in the concealed space to the possibility of failure in the event of a fire. Similarly, the relocation of openings through protective ceilings that expose the pipe to heat, inconsistent with

Jesse

12/6/2022 08:39:13 am

You can support sprinkler pipe from other sprinkler pipe presuming it supports the weight +250 lbs. Not sure that'll support it. I'd consult the manufacturer.

Randy Kimbro

12/6/2022 08:48:00 am

As usual, you guys are all awesome with the responses. I did note the 250# requirement in NFPA plus the weight of the water in the piping. And I contacted the manufacturer (BlazeMaster) as you recommended who said "absolutely not". They said their pipe must be hung from building steel/structure and never from other CPVC.

In addition, while researching this issue, we stumbled on a much bigger one. This BlazeMaster pipe was installed on a sloped, unprotected ceiling of a restaurant. The manufacturer requires that the CPVC pipe be protected or installed against a flat, smooth ceiling. The sprinkler contractor is now in the process of removing the CPVC and replacing it with steel on the exposed vaulted ceiling.

Thank you for the guidance and Merry Christmas!

martin m link

12/7/2022 10:56:56 am

Yes Sir the knowledge,wisdom and experience is amazing! I have learned so much from so many and for Meyer fire making this venue possible
Thank you
Martin M

Hanger Supported by CPVC Pipe Acceptable?

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