Use of PVC or melt-able sprinkler pipe in attics

[Charles McLendon]

I'm finding in some applications PVC as sprinkler delivery is allowable in some sprinklered attics. I find this counter intuitive. Any thoughts would be appreciated.

Thanks,

Charles McLendon, PE, CIH

 

[TravisMack]

You may want to do some research. CPVC has been used in fire sprinkler systems for quite some time (The first CPVC system I designed was in 1990). It is UL Listed and I believe FM approved for use in fire sprinkler systems. It can even be installed exposed in some cases.

So, yes. It is used and it is allowed. There are very specific requirements and compatibility concerns you must adhere to for the installation.

Travis Mack, SET, CWBSP, RME-G, CFPS
MFP Design, LLC

http://www.mfpdesign.com

 

[cdafd]

Cvpc pipe

You have to get the listing for the brand to be used.
Check where it can be installed.

Check the conditions it that are required.

Normally the attic will have fire sprinkler protection, using steel pipe. And, the cvpc pipe will be supplying sprinklers below the attic ceiling.

 

[cdafd]

The space above: CPVC in attics and air plenums

CPVC fire sprinkler products can be installed in attics where the temperature is greater than 150°F (65°C) if ventilation is provided or the product is insulated. However, special, listed sprinklers must be used which guarantee that the pipe will be protected from fire in the event it reaches the attic.

https://www.qrfs.com/blog/179-cpvc-pipe-and-fittings-in-fire-sprinkler-systems-use-and-care/

 

[stookeyfpe]

Charles:

PVC is not an approved or listed material of construction for fire sprinkler piping. Chlorinated PVC (CPVC) polymers that are listed for the fabrication of pipe and fittings meeting ASTM F 442, ASTM F 437, ASTM F 438 and ASTM F 439 are approved materials when using NFPA 13, 13R and NFPA 13D.

Three things to consider because it does seem counterintuitive to allow a particular polymer as fire sprinkler piping. Please consider the following:

1) As others have stated, the use of CPVC pipe and fittings (not PVC) is limited by the UL or FM listing. In the fire protection scheme, attics are a Light hazard occupancy, which means the fire protection hazard is the structure itself since almost all apartment buildings that are not a high-rise building are constructed using wood. Interestingly, I have at least 40 high rise buildings in my jurisdiction where either apartments or hotel rooms are protected with listed CPVC pipe & fittings.

2) The fire sprinkler pipe must be protected from freezing, which is accomplished by insulation or the insulation is negated by virtue that the building in question is in a climate that the attic or other combustible concealed space temperatures don't exceed < 40F.

3) The sprinkler piping is filled with water, which has a high latent heat of vaporization. The water filled pipe, in a sprinklered attic, is adequately protected from melting by enthalpy.

I'm an approving authority for a very large metropolitan fire department for almost 30 years and have extensive experience with NFPA 13, 13R and 13D automatic sprinkler systems. CPVC can fail but the problems we're continuing to see is the chemical compatibility of CPVC with other building materials (internet search CPVD sprinkler pipe + incompatible materials for guidance). Examples of failures are CPVC vs. insulation, fire-stop assemblies, and lubricants used to cut steel fire sprinkler piping.