sprinkler piping in attic

[wickedspins]

Hi,
I have a small commercial building (~4000 sf) with wood framed construction, a sloped roof, and attic insulation is at the ceiling. A wet pipe sprinkler system is being installed for the building with some upright sprinkler heads in the attic. Depending on the locations of these upright heads, it could be anywhere from a few inches above the top of the insulation to 4 or 5 feet above the insulation.

My question is during the winter months where temperature drops to about 30 degrees F, how can I protect these exposed piping from freezing? Most of the pipes can be installed below the attic insulation, but the upright piping and sprinkler heads are exposed. Does NFPA 13 allow tube insulation on these upright piping AND using dry type sprinkler heads?

If not tube insulation, can heating cables be used where needed?

Thanks.

 

[stookeyfpe]

You can either provide an antifreeze loop or you can provide dry pipe sprinklers in those areas.

 

[TravisMack]

As Stookey said, you can run a separate system with anti-freeze in the attic, or a separate dry pipe system in the attic.

Otherwise, if possible, you have the option of dry uprights. However, remember that they are only listed up to 48" in length. Also, the uprights have to be installed with the deflector parallel to the roof if the slope is >2:12. This can be challenging when supplying from below.

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com

 

[wickedspins]

So insulation on the upright piping and/or heat trace is not allowed?

 

[TravisMack]

NFPA 13, 2010 edition allows heat tracing of branch lines if you use UL listed heat tracing - prior editions did not allow heat tracing of branch lines. Insulation alone is not adequate.

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com

 

[cdafd]

Since a fire sprinkler company has to be hired anyway, suggest it be done as soon as possible, and let them advise you on best approach

There may be other factors that cannot be known, that may affect the design

 

[chillylulu]

And heat tracing needs to be monitored.