Septic pipe to Shop?

[JoeJee]

Hello,

We are about to run a sewer line from septic tank to our shop. Nothing fancy up there but a toilet and sink for now. Could be converted to living space in the future.

I have 3” going to my tank. Not sure if it goes to 4” or stays 3”. Will probably run 3” because I have a good drop on the line and it is what I already have. We have always ran regular sch 40 DWV under a house and change to sch 40 PVC Foam Core outside of it. Can I use this stuff if it runs under an area that will be driven on? Our supply house and plumber said it is done all the time. I know they are not the same but I have dug up a bunch of crushed SDR 35 over the years and just want some extra feedback.

 

[Reach4]

Solid dual-rated pvc is not that much more expensive, and not that much heavier, than foamcore IMO. Why not spend the extra?

I think 3 and 4 inch that is only rated DWV is usually foamcore.

Arkansas Plumbing Code 2006 https://www.healthy.arkansas.gov/images/uploads/rules/ArkansasPlumbingCode.pdf

Looks like both 3 and 4 inch can have 1/8 inch/ft minimum slope. Section 704.1 on page 51

 

[Sponsor]

 

[JoeJee]

Solid dual-rated pvc is not that much more expensive, and not that much heavier, than foamcore IMO. Why not spend the extra?

I think 3 and 4 inch that is only rated DWV is usually foamcore.

Arkansas Plumbing Code 2006 https://www.healthy.arkansas.gov/images/uploads/rules/ArkansasPlumbingCode.pdf

Looks like both 3 and 4 inch can have 1/8 inch/ft minimum slope. Section 704.1 on page 51

thank you for the response. Here we have solid sch 40 DWV pipe here but it is thinner than pressure rated.

Approximate prices/ft:
4” sch 40 pressure $5.85
4” foam core $3.48
4” sch 40 DWV (thin wall) 4.57
4” SDR 35 $1.29.

When going about 160+’ it can make a difference. I am leaning against foam core though. My installer said to go with SDR 35 if I don’t want to use foam core…

 

[Reach4]

Here we have solid sch 40 DWV pipe here but it is thinner than pressure rated.

Schedule 4o is a size spec, and for a given nominal size, such as 4 inch, the OD and the ID will be the same whether pressure rated, DWV rated, or dual rated. If there is a thickness difference, one of them is not schedule 40.

Do you have links for these products from where you are shopping.

 

[wwhitney]

Can I use this stuff if it runs under an area that will be driven on?

I think foam core is OK for that, but if you are concerned, just use the solid for the portion under the driveway. Of course, if it's running parallel to the driveway, that might be most of the length, so not an economization over using all solid.

Cheers, Wayne

 

[Reach4]

Approximate prices/ft:
4” sch 40 pressure $5.85

I show $2.8 per foot plus couplings for dual rated. https://www.homedepot.com/p/JM-EAGL...0-DWV-Plain-End-Pipe-531103/100156409#overlay

4” foam core $3.48

$1.15 /ft plus couplings for foamcore. https://www.homedepot.com/p/Charlot...0-DWV-Foam-Core-Pipe-PVC-04400-0200/202018044

3-inch would be cheaper for each. The difference between solid and foamcore was bigger than I expected, however.