NFPA 13D Pex as a stand alone system????

[twd22285]

As a company we have installed CPVC (blazemaster) in houses, with a little bit of copper for aesthetics in exposed applications. However with an increase in the demand for freeze protection, general contractors have been on us about offering PEX piping. After quite a bit of research (not enough apparently) we decided to offer a Rehau RAUPEX system. One of the issues that is common in the area we are working in is lack of water supply. No fire flow data is provided so we run our hydraulic calculations back to the base of riser and prove system performance off of a flow (bucket) test from the most demanding heads. About 25% of the time a pump needs to be added after the 'bucket test' fails to meet the water delivery demand. So when we did our first house in PEX piping I designed it as a stand alone system because of the possibility of adding a pump later. If i did a multipurpose system it takes away the option of installing a pump at the base of riser. I know of another fire sprinkler company that did this, and i know the Fire Marshal approved the plans as a stand alone system, and he signed off on the one the other company did. I made sure the Rehau rep knew i was doing a stand alone system and she had no problems with it. I read Reahau technical manual for residential fire sprinkler systems and it said nothing to the affect of multipurpose only. HOWEVER, today our local Blazemaster rep stopped in and upon telling him we our in the process of installing our first PEX system he told us that PEX is not allowed as a standalone system. He had literature that Blazemaster had printed on pro's of CPVC and con's of PEX, one of them said "PEX cannot be installed as standalone system based on NFPA 13D" I have looked in NFPA 13D 2007 and 2010 and cannot find any such wording. Does anyone know of any such remarks stating i cannot install a PEX system as standalone? Thank you in advance for your help.

tony

 

[twd22285]

Found it. 5.2.1.2 and 5.2.1.3. Working pressure for stand alone not less than 175 PSI.

tony

 

[b1ueshift]

Thanks for letting us know - that information may come in handy one day now that residential systems are becomming more common.

 

[gouveia]

This is a very interesting idea. So can one put a single hose bib valve on the system and call it a "multipurpose" system? I will have to get a hold of my Reahau rep and do some more investigation.

 

[stookeyfpe]

We've been using PEX in Habitat for Humanity houses here in Austin for about 3 years. It works very well and it's easy to pull the tubing and assemble it. Just remember that it needs to be covered by gypsum wall board as it has a low melt point.

 

[twd22285]

I think the idea is too hook it up to something that gets used on a daily basis throughout the year (toilet,sink). The use of such fixtures acts as its own pressure relief valve if you will, introducing original system pressure every time they are used. If a hose bib is used, during winter months it would not get used. The people at Rehau have a printout that says you can use RAUPEX as stand alone as long as you have a pressure relief valve set at 130 psi, with AHJ approval of course. I found out yesterday there is a proposal for the 2013 NFPA 13D to allow pipe with working pressure of 130 psi to be used as stand alone as long as there is a pressure relief valve set at 80 PSI. @stookeyfpe- What kind PEX are you using? Here is an excerpt from Rehau's fire protection technical manual:
Protection shall be provided for RAUPEX
pipe and EVERLOC fittings. The minimum
protection shall consist of either
- one layer of 3/8" (9.5 mm) gypsum
wallboard,
- a suspended membrane ceiling with
lay-in panels or tiles having a weight
of not less than 0.35 lbs per square
foot (1.7 kg per square meter) when
installed with metallic support grids,
- 1/2" (13 mm) plywood soffits, or
- one layer of 1/2" (13 mm) plywood.


Thanks for the replies

tony