Dry sprinkler heads in Wet-Pipe sprinkler system
Dry sprinkler heads in Wet-Pipe sprinkler system
(OP)
In areas that don't really freeze (2-3 days out of the year where temperature might drop to 25 deg F), is it possible to use some dry sprinkler heads in a wet-pipe sprinkler system, such as in attic (insulation at ceiling) or under overhangs?
Thanks.
Thanks.





RE: Dry sprinkler heads in Wet-Pipe sprinkler system
As for attics, it depends how high the dry barrel has to extend to put the sprinkler deflector within the appropriate distance from the roof deck. 8.4.9.1 states that the minimum length of the sprinkler barrel shall be in accordance with the manufacturers listing, to avoid freezing by conduction.
Depending on the length, you're probably looking at a made-to-order sprinkler. At $100++ per head, it better be a small attic to be profitable in any way. Also, if you're sprinkling the attic, I assume it's a full 13 building? Double check with the AHJ to make sure the attic doesn't require a separate zone.
To answer your question, it MIGHT be possible.
RE: Dry sprinkler heads in Wet-Pipe sprinkler system
For the attics, It looks like the dry barrel will have extend 5-6 feet above ceiling insulation. Do you have the title of that section 8.4.9.1? I'm not finding anything similar under 2002 edition.
How are these dry sprinkler heads installed in a wet-pipe system? Do they still need an air compressor to pressurized the barrels?
RE: Dry sprinkler heads in Wet-Pipe sprinkler system
A 6' dry sprinkler would not be my cup of tea. Like a vertical sprig, you'll have to restrain the barrel. Call some wholesalers for pricing...try not to fall out of your chair when you get the quote.
A dry sprinkler is essentially a pipe nipple with a sprinkler at the end. At the end opposite the sprinkler, there is a plug sealing the barrel, connected thru to the heat sensitive element of the sprinkler. When the sprinkler pops, plug drops and water flows...hence "dry sprinkler".
By virtue of this, the barrel has to extend from the sprinkler down into the warm area a sufficient length (victaulic has some nice literature on sprinkler barrel length). The fitter has to either have his branch line hung, or be pretty damn sure of his elevation before you order up the sprinks.
In your attic situation, your branchline would run in the warm space, with a pipe nipple made into the o'let, 1" tee made on to the nipple, with your dry sprinkler made into the opposite leg of the tee. A 1" plug is made into the tee's outlet. Sounds a bit strange, but if you look at the thread of a dry sprinkler, it's long enough that when fully made into the o'let, it will extend down into the water stream.
No air compressor, dry sprinkler is a sealed unit. Hope I was clear enough. 8.4.9.1 is new for 2010. States " Where dry sprinklers are connected to wet pipe sprinkler systems protecting areas subject to freezing temperatures, the minimum length between the sprinkler and the fitting shall be in accordance with the manufacturers instructions."
RE: Dry sprinkler heads in Wet-Pipe sprinkler system
RE: Dry sprinkler heads in Wet-Pipe sprinkler system
is this just a general question or for a specific building??
RE: Dry sprinkler heads in Wet-Pipe sprinkler system
RE: Dry sprinkler heads in Wet-Pipe sprinkler system
it is under specail which was 8.4.9 in the 2002
8.4.9 Dry Sprinklers.
8.4.9.1* Where dry sprinklers are connected to wet pipe sprinkler systems protecting areas subject to freezing temperatures, the minimum length between the sprinkler and fitting shall be in accordance with the manufacturers' instructions.
8.4.9.2* Where dry sprinklers are connected to wet pipe sprinkler systems protecting insulated freezer structures, the clearance space around the sprinkler barrel shall be sealed.
RE: Dry sprinkler heads in Wet-Pipe sprinkler system
NewtonFP: I'll look at the anti-freeze option as well. Going to get a quote from the contractor.
cdafd: I have 3 single story buildings (2 wood framed buildings with 2,000 sf and 3,000 sf, 1 metal framed building of about 2,000 sf). All have 5:12 roof slope with insulation at the ceiling. All buildings fall under NFPA 13 (2002 edition). I think it's around 100 heads in the attic spaces and overhangs for all 3 buildings.
RE: Dry sprinkler heads in Wet-Pipe sprinkler system
Check out figure 1 on page 2.
Once it goes...it's garbage. The tee is there to maintain clearance for the longer thread on the sprinkler. It isn't necessary for most o'lets, as they are deep enough that the sprinkler can be properly made in and not obstruct the waterway, but it's always good to check.
RE: Dry sprinkler heads in Wet-Pipe sprinkler system
RE: Dry sprinkler heads in Wet-Pipe sprinkler system