Support for piping under structural slab. 2

[Sirpa]

I am looking for the best way to support sanitary piping below a structural slab in a building that is to be constructed close to a river.

I have seen details for clevis hangers with stainless steel rods supported under the slab, but am not convinced that this is the best method to use.

I also would like to know what the recommended pipe spacing would be. The sanitary lines vary from 2" diameter to 4" diameter.

Please help!

Thank you.

Sirpa
Thunder Bay, ON, Canada

 

[PEDARRIN2]

I don't know you need to have stainless steel. How about standard hangers/rods and then paint them after you get the pipe hung?

I would think about using PVC pipe so you don't have to worry about the pipe corroding - and I would trust a PVC joint over a cast iron joint if it was submerged.

For cast iron pipe, I would support it at each fitting and/or joint and have a 10' maximum spacing.

For PVC pipe, it depends on the expected temperatures. Between 60-100 degrees F, you are looking at 5-7 feet maximum spacing.

 

[kmcd]

If settlement is an issue, and it usually is under a structural slab, we've used the clevis hangers to support the piping and placed some expanded polystyrene voiding on edge on top of the pipe prior to backfilling.
This helps prevent the weight of the soil from dragging down the suspended pipe as it settles below the slab.