Dry Pipe Sprinkler Fitting Failure
Dry Pipe Sprinkler Fitting Failure
(OP)
I am looking into a the cause of failure for a cast iron fitting that is part of a 12 year old dry pipe sprinkler system. The tee-fitting was located at a high point and appears to have broken during freezing weather due to trapped water.
The company who does the annual testing and makes repairs says that the dry lines are very corroded and that debris could have trapped water in the pipe, which then froze and broke the fitting.
Has anyone had experience with water getting trapped in a dry pipe sprinkler system after the dry-valve testing?
Can corrosion trap water in the system?
What other mechanisms could trap water in the dry pipe system?
Is there anyway to prevent this from happening in the future?
Any insight or experience you could give me in this matter would be most appreciated. Thank you.
The company who does the annual testing and makes repairs says that the dry lines are very corroded and that debris could have trapped water in the pipe, which then froze and broke the fitting.
Has anyone had experience with water getting trapped in a dry pipe sprinkler system after the dry-valve testing?
Can corrosion trap water in the system?
What other mechanisms could trap water in the dry pipe system?
Is there anyway to prevent this from happening in the future?
Any insight or experience you could give me in this matter would be most appreciated. Thank you.





RE: Dry Pipe Sprinkler Fitting Failure
RE: Dry Pipe Sprinkler Fitting Failure
The fitting that broke is a 1 1/4 x 1 x 1 1/4 tee. The piping connected to it is unlined black steel threaded pipe called Dyna Thread 40.
The dry system is a closed sprinkler system kept under pressure (33 psig) by way of an air compressor and a regulator. When pressure drops in the system (such as when there is a fire and a sprikler head activates) the dry valve opens and fills the pipe system with water.
The dry valve is wet tested every third year so water is introduced into the piping system every third year. All pipes are sloped to drain out to a main drain and after the test the lines are drained (the dry valve can't be reset unless the system is drained).
Therefore, if there was still water in the system that froze and broke the fitting, it must have not been able to drain when the system was drained after the test.
Has anyone experienced or heard of corrosion causing blockages in a dry pipe system?
Thanks for your help.
RE: Dry Pipe Sprinkler Fitting Failure