We've had several mishaps where systems tripped when the plant shut down their air compressors over holidays. There were some installation errors that also contributed to the false trips.
Also water pressure switches that were disabled so that no alarm sounded or trim valves closed to prevent drippage through WMG's, again resulting in no alarm and system filling and freezing. I've never heard the air thinning theory. 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 10:47 AM To: [email protected] Subject: Dry Pipe System Dilemmas Thought I'd tap the vast knowledge of the group here. Over the past couple days we've have numerous sprinkler breaks due to frozen pipes. The part that perplexes me is dry pipe systems. We have had at least a couple dry pipe system activations/breaks with no apparent reasoning as to why or how water would be in the system. One dry pipe activated/tripped, for no apparent reason. This charged the system and caused the fire pump to come on. Upon investigation, no water leaks of any sort were noted. A roving sprinkler contractor stopped in and said that when air cools it thins and this could create an imbalance in the pressure differential at the valve, thus allowing the vale to trip. I suppose this could happen if the pressure differential between the air/water was within a few psi but other than that, it doesn't make sense to me. Another dry system froze due to water in the system (unknown as to how much water was left in the system) but we can't figure out how the water was in the system. The only explanation we have at this time is water was left in there or never properly drained. Anyone else have any suggestions as to why dry pipe systems would activate and/or have water present in them enough to cause breakage from freezing? Thanks for all insight. Smitty Steven Smith, CFPS | Fire Protection Engineer II Colorado Springs Fire Department | Office of the Fire Marshal Technical Services | 719-385-7362 _______________________________________________ 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)
