View Full Version : Below Slab Drain Material

02-28-2016, 07:59 PM
I see a lot of threads about trench material, but not much about pipe material. As I understand it, PVC should not be used for high temperature environments. I'd like to think we can avoid dumping >140* liquids down the drain; however, I know better than to assume. Stainless is out of the budget unfortunately. I've seen a lot of breweries use cast iron and ABS. Does anyone have practical experience? At first blush, ABS seems to fit the bill. Thanks -John

02-29-2016, 12:31 PM
ABS is fine. Just remember that you'll (hopefully) never see these pipes again, so do them right the first time. Lots of clean-outs will make life much easier when something clogs the line.

03-02-2016, 06:34 AM
Thanks for the response Timm. Should I concern myself with finding solid wall ABS or is the cellular/foam core acceptable? It looks like both are good up to 180* F. Thanks again. -John

03-02-2016, 09:00 AM
We've had no problems with the cellular ABS. It's cheap, light, easy to find and work with.

Just don't cut any corners here--your drain system will be, literally, set in stone. Over-size the lines, and if possible, over-slope them. Brewery sludge doesn't flow like regular domestic waste.

Oh, yeah--keep your brewery system completely separate from any domestic waste--including brewery toilet, if you have one--until after your sedimentation tank!

03-08-2016, 10:59 AM
Timm can you elaborate on a sedimentation tank? Where it's placed, how it's accessed? Our city recommended just this, but I'm completely unfamiliar with them. (Going to Google it right now).

03-09-2016, 07:02 AM
We actually have sch80 in the slab and have not had an issue. Yes, be sure to have several clean outs with easy access and by that I mean not tight in a corner that you cant get a drain snake into. Not sure if you are going to have any food but keep the food and brewery separate that way if one side or the other clogs up it wont stop production on the other side. We even used sch 80 on our boiler drain but, there is a valve that senses our hot water and opens up the cold water to cool it down 5 years into it and no problems yet. One last bit of advise its great to have blue prints but many times contractors "adjust" thing to make life easier. Take many many pics of the in slab wiring and plumbing work before the concrete is poured that way when it comes time to say where exactly is this pipe you will have actual evidence of where it really is.

03-09-2016, 01:15 PM
I would avoid sch 80 PVC for under-slab use due its high Coefficient Of Expansion. IIRC, cellular ABS has a much smaller COE, and is less prone to stress-fracturing. The ends of the pipes will be trapped in concrete, dirt, and gravel, making it difficult or impossible to allow for expansion/contraction.

The absolute only thing that should go beneath the slab is the drain system. Mount everything else--plumbing, wiring, etc. on Uni-strut on the walls. You'll be thanking yourself every time you need to mod/repair/add on to existing systems.

The sedimentation tank is basically a septic vault. It allows much of the sediments in your waste stream to settle out, and allows acids and bases to react and neutralize each other before entering the sewer system. Sanitizers also tend to be neutralized in the sed. tank. All these things will make your local sewage treatment plant managers much happier with you, even if a sedimentation tank isn't required by local laws/regs.

A concrete, steel or plastic septic vault is fine for this--sizing depends on the size of your brewery, but 1,000 gals would be about the minimum. If the tank will be installed below a driveway/parking area, make it stout.

You want to keep this separate from domestic sewage for obvious reasons--you'll have to pump this vault regularly and may have to enter it occasionally. Which is better--brewery waste, or... well, you get the point. Keeping the two systems separate also keeps nasty smells from the vault down.

The vault needs to be located where drain grades (go steeper for brewery waste, it doesn't flow like sewage) and accessibility dictate. You'll need to pump it out, so be sure it's easy to get to. It will smell, so keep it away from public areas and the kitchen (if any). For obvious reasons, it should be outside. A tall vent stack will help to minimize the perceived smell.

Good luck and good brewing--