dry heads on a dry system
dry heads on a dry system
(OP)
I have a question form a customer, a nursing home, on system design. In my experience, all heads which are on drops in a dry system need to be dry heads to prevent water from freezing in the drop because the drops will not drain through the main. The customer recently had a dry syst. installed (in Ohio) and said that the pendants covering exterior areas are not dry heads. It is a cpvc system with an oilless compressor. Can you cite a code for me to check out that covers this issue? Am a member, and have checked NFPA website, but can find nothing specific. Thanks for any help.





RE: dry heads on a dry system
(1) Upright Sprinklers
(2) Listed dry sprinklers
(3) Pendant sprinklers and sidewall sprinklers installed on return bends, where the sprinklers, return bend, and branch line piping are in an area maintained at or above 40F
(4) Horizontal sidewall sprinklers installed so that water is not trapped
(5) Pendant sprinklers and sidewall sprinklers, where the sprinklers and branch line piping are in an area maintained at or above 40F, the water supply is potable, and the piping for the dry pipe system is copper or CPVC specifically listed for dry pipe applications
I imagine you would run into an issue with the 40F requirement just about anywhere in Ohio.
RE: dry heads on a dry system
RE: dry heads on a dry system
Maybe it not impossible but I have problem seeing how a mess you describe could get by everyone.
RE: dry heads on a dry system
RE: dry heads on a dry system
I thank you for your replies and information, it is very much appreciated. I have the Sprinkler Systems Handbook, and have been checking 13 on the nfpa website, but things are a little vague on system design requirements for dry heads. Thanks again, Chris.
RE: dry heads on a dry system
Could that be what your client has?
RE: dry heads on a dry system
5.3.1.1.1.6* Dry sprinklers that have been in service for 10 years shall be replaced or representative samples shall be tested and then retested at 10-year intervals.
They have a very high failure rate, so if they have not been test they should be.
RE: dry heads on a dry system
You did not ask, but here is info on UL sprinkler testing
RE: dry heads on a dry system