I have my first Energy Star home that has sprinkler piping installed in the attic. The pipes run about 6 inches above the drywall. The sprinkler company says there must be an insulation void between the ceiling top and the piping to avoid freezing, so the insulator placed fiberglass batts over the piping to keep the blown fiberglass away from the pipes, which will leave (roughly) a 6-inch by 24-inch air gap directly above the drywall at each pipe run. This, of course, violates the Energy Star insulation-to-air barrier alignment guideline. I don't have a good solution to offer, but I'm wondering if removing the batts and blowing the insulation (R-38) directly around the piping, which would leave roughly R-18 over them, would suffice. Has anyone else dealt with this issue yet? This will be the norm for all new homes in PA.
I believe the Sprinkler Company has a problem not stated. NFPA does not allow any thing to rest on a sprinkler pipe. Blowing insulation around the pipe would not allow the required periodic visual inspections. Resting batts on the pipes also prohibits visual inspection and additionally cause the potential for the pipes to deflect. Deflection changes the water flow - think flex duct bends etc.
With a wet sprinkler system install in the attic, you are pretty much stuck with installing the insulation on the roof deck. The sprinkler has to be able to spray water on the roof deck as well as below. Prior to my certification as a HERS Rater, I was administrator of a medical facility that was sprinkled. The batt insulation was installed on the roof deck. It sags, looses contact with the deck, drops out, lands on sprinkler pipe and other places you don't want it.
How high is the attic space? I am slightly surprised there are not sprinkler heads along the roof deck also.
Since there is little choice except to include the entire attic within the thermal envelope - I believe the long term solution is to foam the roof deck
Your install is subject to local fire inspection. I would keep all of the above in mind, and visit with them. Start at the Fire Dept. They like tight houses. Explain how you do tight shell, and see what they say. Then approach the actual building inspector.
We run into this problem a lot in North Carolina. An alternative to foaming the roof deck & gable ends is creating a horizontal boxed chase for the sprinkler lines. Typically, our builders keep the top of boxed chase lower than the ceiling insulation so there isn't a need for a 6-sided wall assembly. The box (built with drywall, plywood, Thermax or equivalent) is air sealed with an appropriate material (mastic, caulk, foam). I also recently found this Literature Review from the NFPA to acknowledge that there is a conflict in sprinkler freeze protection and ENERGY STAR. The article also offers a variety of solutions. http://www.nfpa.org/assets/files//pdf/research/rfsprinklerinsulatio...
The real solution is to say to the sprinkler guy - "I will not force the insulator to take responsibility for your pipes freezing - install them in the walls so all pipes are inside the heated shell"
Tried it; I might as well have asked for sacrifice of his first born. The builder has the final say, and they were OK with it. I disclaimed any responsibliity for when the pipes freeze, and they signed the ceiling insulation item of the checklist. I don't care for the provision for them to be able to sign off on several items, but I am thankful for it in the case of sprinklers.
We air seled some condos a few years back and their sprinklers were in a cathedral ceiling with scissors trusses. One of techs was smart enough to take a picture and tell the job super there there was on pipe that was especially vulnerable - he didn't like the answer he got so he emailed the picture and a note. Wouldn't you know, it broke and soaked all three units in the stack. We were named in a lawsuit, but were immediately let out when the judge saw the e-mail.
Now we take lost of picture
We have 50/50 success in getting pipes out of the attic
We have been dealing with this for a while. Aside from the insulation freeze issued which if sever enough may warrant a glycol system (not the greatest option since it requires third party inspections for perpetuity. The other issue is air leakage control, the sprinklers are a disaster in this regard, they can easily add as much as a leaky recessed can light. To make it more challenging CPVC is a finicky material that requires approved sealants. We developed the following sprinkler air seal to over come the leakage issue and protect the head from harmful sealants.
The other thing to consider is having the last run in the sprinkler system feed a toilet to keep the water in the system cycling rather than stagnating. If the insulation strategy is to use air permeable insulation then air movement through the insulation must be mitigate for the insulation to do it's job retain heat (and protect the pipes that the insulation is covering).
Good luck with your projects
Thanks Gavin, interesting product. I'll run it by those doing sprinkled buildings and hope they pick up on the benefits.