We have a lot line sprinkler installation with sprinkler piping being recessed in a furred out wall. We are concerned about pipe freeze ups.
Since we are connected to the existing system that serves the entire floor it would not be feasible to do a dry pipe system or add anti freeze. Does anyone have a good calculation to determine if the piping will freeze in the wall cavity? Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe
5 Comments
Jonathan Sullivan
12/10/2020 09:28:41 am
You could try this to get started: https://www.wbdg.org/guides-specifications/mechanical-insulation-design-guide/design-objectives/time-freezing-fluid-insulated-pipe-calculator
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BK
12/10/2020 10:31:17 am
By code the cavity must be maintained at 40 degrees for wet system piping. Can you monitor ambient and account for all fluctuations accurately? If there are too many variables or lack of a controlled environment, then dry or antifreeze may be the option to meet code as an auxiliary system valve within the existing wet system per NFPA 13, 7.1.3
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Glenn Berger
12/10/2020 10:41:36 am
If there is a chance of freezing, recommend a heat tape system be installed on the concealed pipe sections.
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Brian Gerdwagen FPE
12/10/2020 11:24:36 am
We have done this calculation before as a means to show why a dry system or listed heat-trace was required. The simple answer was stated before: NFPA 13 requires wet systems to be installed in areas that are maintained at 40F. Listed heat-trace would be the only acceptable option from what I understand of the situation.
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Jonathan Joseph
12/10/2020 12:52:23 pm
What type of material is the exterior wall made of? Are they putting up foam panels before the finish on the exterior? That will help tremendously. How cold does it get in the area?
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