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It's clear that gridded dry systems are no longer allowed by NFPA 13 (for the last 30-40 years or so), but what about a looped dry system?
If I understand it correctly, gridded dry systems are not allowed because water delivery time is typically hindered, and gridded systems may not be set up to drain particularly well. Is that true of looped dry systems? If the total volume of a looped dry system is small (200-500 gallons), and water delivery time is not an issue, I could see major advantages to looping a dry system for areas like parking garages or attics. Thanks in advance. Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe
9 Comments
Taylor Schumacher
12/18/2020 09:25:10 am
Yes, looped systems are allowed. NFPA 13 7.2.3.10 excludes gridded dry systems alone and the commentary suggests looped systems are allowed.
sean
12/18/2020 09:41:05 am
Looped large dry systems can work as well they may just require specialized water delivery calculations
Glenn Berger
12/18/2020 09:45:42 am
It needs to be noted that Mr. Schumacher is quoting from the 2016 version of NFPA 13. In the 2019 version, it is Section 8.2.3.10.
Franck
12/18/2020 09:54:33 am
The only possible limitation is that you add volume (more large pipes for the loop) and then may exceed the system size limitations (either based on the volume or on the water delivery time to the most remote sprinkler).
Andrew Paul Valente
12/30/2024 09:59:06 am
When you loop you should be reducing the diameter of the pipe, since the flow splits. As a result, probably more smaller pipe. This will ultimately result in a small volume since the cross-sectional area is based on the square of the radius.
J. Lutz
12/18/2020 10:32:15 am
Definitely not disallowed.
Taylor D. Jenkins
5/21/2024 09:07:45 am
What about a "double-looped" system? For instance, if you have a loop running around a typical hip-roof attic and you've got a center riser, can you tie into the loop in two locations? 13 doesn't really discuss when a looped system turns into a grid. None of the branchlines would be connected so in my opinion this would be acceptable as long as you meet the discharge time through the RTC...thoughts?
Jason Andrews
3/9/2025 12:51:25 pm
I would love to know the answer to this one as well
sean
3/9/2025 09:09:59 pm
i think the key is loop two paths, gridded more than 2 paths Leave a Reply. |
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