Malleable fittings can fail for a multitude of reasons. Lines installed out of square in such a way that the fitting is stressed, fitting was dropped, bad casting, etc.
Sloped lines over time have a tendency to get "unsloped", especially in venues where there may have been modifications to the sprinkler systems over the years. Low points are created, systems are not completely drained and the first long freeze and you've got the makings of a big ICEE machine. Also any lines that may come in contact with operating machinery that can setup vibrations or other harmonics in the sprinkler system. When connecting to big air compressors for instance vibrations from the air compressor can transfer to the sprinkler system piping and cause small fittings to fatigue. Or there's the other factor of another discipline doing work and hanging on a sprinkler line and twisting a fitting. A small leak becomes bigger until you finally get that very special call at 4am. The ice blockage doesn't always grow in a logical manner. It depends on where it starts, pitch of pipe, fittings, where the source of water is originating, blockage within the pipe from other matter, or other factor causing resistance to migration of the ice formation where it can't grow longitudinally. Craig L. Prahl, CET Fire Protection Specialist Mechanical Department CH2MHILL Lockwood Greene 1500 International Drive PO Box 491, Spartanburg, SC 29304-0491 Direct - 864.599.4102 Fax - 864.599.8439 [email protected] http://www.ch2m.com -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Smith, Steven D. (CSFD) Sent: Wednesday, December 17, 2008 12:56 PM To: [email protected] Subject: RE: Dry Pipe System Dilemmas One break occurred in the drum drip of an unheated warehouse (self explanatory as you mentioned). The other break appeared to occur at an elbow where the horizontal pipe turned vertical in an combustible concealed attic space. I didn't look at it personally so I'm not sure if the pipe was completely horizontal or if there was enough slope to it to collect water at the elbow. My guess is there was enough slope to it. Next question... How much condensation can form on the insides of DP systems? Let say for conversation, a gallon of H2O collects in a location that isn't drained out. I know water expands when it freezes, but wouldn't the expansion take place back in the "dry" portions of the system? I mean unless there was enough water there to hold things from expanding into the system and cause them to expand outward, the water "should" expand into the dry portions of the system.... Shouldn't it? Path of least resistance. Steve -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: Wednesday, December 17, 2008 9:01 AM To: [email protected] Subject: Re: Dry Pipe System Dilemmas Where did the breaks in the system occur? That may help in diagnosing the problem. In a previous life we had a dry system that froze and broke at the drum drip due to lack of maintenance (also the drum was in an unheated space). We had another where there was over 100 low point drains in an attic system and one may have been missed during maintenance / after testing (I think we ended up tagging 156 low point drains after that happened). There is always some water in the systems, if they are not maintained properly things can happen. Andrew Weisfield _______________________________________________ Sprinklerforum mailing list http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field) _______________________________________________ Sprinklerforum mailing list http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field)
