Underslab Plumbing Questions

[Gundraw]

I am putting in the plumbing under the slab in my workshop. I am doing some floor drains in a few different places and wanted to confirm my plan before proceeding. I made a quick sketch of the layout but there seems to be a problem posting pictures on this site right now.

My questions are this:

1. I was told to put all schedule 40 under the slab. I later realized that my hardware store carries both schedule 40 couplers and DWV couplers. However, all the wyes, tees, specialty fittings etc are simply marked DWV. Are these appropriate for under slab?

2. I was going to dig the trenches for the PVC and then embed them in AB3. This is simply how I did all my drainage pipe, is this still appropriate for this application or do I need to switch to a different gravel type?

3. I have gotten a LOT of warnings about potential blockages in an under-concrete P-trap for a floor drain. There is one drain that could get some sediment, and I was planning on making a small "pit" with a grate for sediment collection. I figured that in this pit, I could put a drain stub up, along with a stub up (with cap) on the other side of the trap to give access to both sides. I am hoping this makes any clog in the trap clearable?

4. Are these drains ok for the lower usage areas that shouldn't get any sediment? I am also making sure these are suitable to embed in a 6" pour. Floor drain with integrated cleanout

5. Since I can't post a picture, this makes it a little more difficult to explain, but in short, I have a main 3" trunk that run about 50 feet (with a 45 here and there). One end terminates in the sewer, the other end sweeps up with a cleanout and vent to the roof. The trunk has 4 branches, one 3" for the big drain mentioned before, and three 2" branches for your typical drain/cleanout floor drains. I was under the impression that as long as a branch is less than 15' from the main trunk, it does NOT need any additional venting, is this correct?

 

[John Gayewski]

If your only putting in floor drains the venting should be fine as you have described. The main issue I see would be the traps drying out due to infrequent usage.

 

[Sponsor]

 

[Jeff H Young]

As John mentioned the p traps can dry out my code would require a trap primer yours if not UPC might not require one also you can pour a little water down drain once in a while to keep it from drying out.
I dont know what type of shop or why sediment would be going down drain it might be of interest to inspector whats going down sewer industrial waste of somekind

 

[Gundraw]

I am not anticipating heavy loads of anything other than water, but as I found in my last garage that had a floor drain (not under the cars even) they CAN clog, so I figured I would do everything I could to avoid this.

Yes, I already have a service routine in my old shop of keeping traps wetted and plan on continue at this location.

So you guys seem to be good with my layout (if I described properly), but I also very concerned about the other questions, particularly the fitting thickness and gravel type. Does all of this seem ok to use?

 

[Jeff H Young]

pipe sch 40 dwv and the fittings I think will only say dwv . we usually just use sand around here I think gravel up to 3/4 is good too

 

[John Gayewski]

Dwv fittings and couplings are "recessed" meaning when you insert a pipe there should be a smooth transition. Sched 40 fittings are longer and are not recessed. Use only sched 40 dwv fittings.

We use clean rock for pipe bedding, then clean rock to a foot over the pipe, then native soil.

 

[Jeff H Young]

I wasent sure the fittings were marked sch 40 but definately on same page with john. I dont know maybe its weather but on some places our trench might only be 6 inches into the soil like a kitchen or wash machine run We just throw native on top or a little sand