We have a building that is constructed. It has a very deep footing.
The contractor originally submitted an Ames In-Building Riser, but it's too deep for the in-building riser in the building's (essentially) existing condition.
They proposed using C900 to come under the footing, without a sleeve, going below the 12" footing and then stubbing up into the riser room without thrust blocks.
We have concerns about restraint and a change of direction underneath the foundation.
NFPA 13 applies and C900 is a permitted material, which is what the contractor has suggested makes it acceptable.
Is routing C900 under a building footing, changing direction, and then stubbing into the building acceptable?
2/16/2023 08:17:35 am
I don't think it's a good idea, but NFPA 13, 2022 ed A18.104.22.168.1 states: The individual piping standards should be followed for load and bury depth, accounting for the load and stresses imposed by the building foundation.
2/16/2023 08:18:14 am
I have concerns as well. Primarily the lack of restraint and thrust blocking at the change of direction. How are they expecting the pipe to not separate?
2/21/2023 01:10:36 pm
This, Nothing worse than having your underground blow out during testing especially under a footer that's supporting the building.
2/16/2023 08:18:25 am
Using C900 piping below a footing w/o a sleeve may or may not be permissible. First consult the applicable authorities if this is allowed in this jurisdiction.
2/16/2023 08:20:05 am
!. Adequate clearance between C900 and footing.
2/16/2023 08:21:39 am
You need to transition @ 5'-0" out from the building to Cement Lined Ductile Iron with mechanical Joint Fittings. This has been done for years and is still acceptable. I know the fashion is the new in building riser but go back to the old trusted way. It still works well.
2/16/2023 08:36:32 am
2/16/2023 10:16:34 am
I did not say it was "Preferable", I do love the in building riser, however it does not meet every need. I will say that cement lined ductile iron is preferable over C900 going under a footing and slab.
2/16/2023 09:04:20 am
I agree with James. The riser / stub-in / lead-in should be ductile. If you choose to use C-900, it should be sleeved. I have seen a few instances where a fork truck has hit and snapped the C-900 at its base.
2/16/2023 08:43:46 am
Have you considered using an In-Building Riser? All one piece stainless steel. AMES makes them from 4-inch up to 12-inch. and it will connect to the C900. You can order it in a length that will put the connection past the footing bearing zone.
2/16/2023 08:48:29 am
We have had Ames make custom lengths from the factory in the past. Check into that option as well.
2/16/2023 10:40:58 am
Every joint between pipe and fitting must be restrained against separation per NFPA 24 (2022) Section 10.6 which may include thrust blocking (10.6.1), or more likely; restrained joint systems (10.6.2), or other connection methods (10.6.3).
2/16/2023 12:35:26 pm
James covered this well. Transition from PVC to ductile iron five foot outside building and several have mentioned restraint which you also have to be concerned with the Ames stainless steel riser installs.
2/16/2023 03:00:20 pm
I agree with changing to DI pipe at 5'-0" out. This may not be code driven, but it's definitely a good idea. Also, I'm not sure how cost compares in other parts of the country, but where I am, there is very little cost difference now between C900 and DI pipe. It used to be 50% to 70% in savings to go C900.
2/17/2023 08:54:15 am
Have them use ductile iron from the interior flange installed at a minimum height of 1'-0" AFF down under the footing and then a minimum of 5'0" from the outside face of the footing. IIRC code says piping within 5' of the building exterior shall be of a type resistant to mechanical damage, or something to that effect. And But Ames does make the IBR with different lengths of legs if you do want to stick with Ames.
James Art. FPE
2/22/2023 11:56:06 am
J.James, and R Hinson:
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