For a project that has seismic expansions and the fire sprinkler piping is predominately CPVC, are seismic loops or assemblies still required?
If so, is there are preferred installation method? Would we need to transition to steel, then back to CPVC, in order to install a Metraflex or similar product? Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe
7 Comments
Anthony
12/13/2023 08:06:21 am
Yes its required, you can transition right at the loop joint.
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Aaron
12/13/2023 08:21:31 am
Keep in mind that the activation force for a pre-fab/manufactured expansion joint is dependant on the piping material...ie most are for steel pipe and have a higher activation force (axially) than a loop designed specifically for plastic pipe. The need for a lower activation force with plastic is based on the critical buckling (think when pipe would want to snake if unrestrained)...some loops designed for steel pipe would never activate/deflect until after the critical buckling load of comparable plastic pipe has been exceeded.
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Glenn Berger
12/13/2023 08:13:28 am
I do not know of an exception to seismic requirement when utilizing CPVC piping. As far as the ability to use metraflex, you will need to contact the mfg for guidance.
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Shahpoor
12/13/2023 08:27:28 am
When passing through a sesimic expansion gap, the piping system should be designed to have enough flexibility to accommodate the difference in movement of the two parts of the building, regardless of the material used. Usually the two buildings (depending on elevation above first floor) move 2 to 4 inches with respect to eachother.
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Ken Thackery
12/13/2023 09:34:04 am
Confirm it is an expansion joint or a seismic joint? Expansion joints do not require a Metraflex- CPVC has an offset detail to allow for expansion every few hundred feet if you have long runs. If you are crossing an actual seismic joint, meaning it's called out on the structural plans and has a movement value assigned, use steel pipe for this as 4way bracing is required within 6-0 of each side of the Metraflex. Typically ground level is +/- 4" Metraflex and may increase with building height but confirm with an RFI answered by the structural engineer. * *They(Arch\Eng) may want a Metraflex at an expansion joint but if it's not called out they will have to pay for it. In my experience KPFF has been the most helpful resource -on my last large project using over 40 Metraflexes at Seatac airport, obviously there was no cpvc used.
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James Art FPE
12/13/2023 02:11:32 pm
Mr. Thackery, or anyone:
Reply
sean
12/31/2023 06:14:30 pm
CPVC is not exempt from seismic. but it has some caveats as it has more flex it helps but requires more frequent hangers as well.
Reply
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