How Do I Plumb a Food Concession Vehicle?

[HayZee518]

when you are ready for the electrical shoot me an email at srf12980@localnet.com and I'll put together a .jpg that you'll be able to view with msn "paint"

[Pig Daddy]

OK LazyPup,
I been making progress on the plumbing project. Finally decided to go with the Fernco fitting. But now I'm ready to run my vent and it's getting very crowded.

What I would like to do is to assemble the vent line (the grey pipe in pix) with threaded PVC connectors from the double sanitary tee, instead of gluing it all together. The reason being is that if I ever had to get the HW heater out of there, I would have to cut out the horizontal vent line. It doesn't look like it from my drawing, but that is indeed the case!

1 - Is it legal to assemble the grey vent line with threaded PVC connectors?

2 - Can I use the tighter VENT ELBOWS instead of SANITARY ELBOWS in the vent's transition from horizontal to vertical?
Thanks again!

[LazyPup]

All fittings on the vent line MUST BE made with DWV Sanitary fittings.

May not use threaded fittings.

may not have a drain and vent back to back.

The easy solution is to replace the sanitary cross with a sanitary Tee with a cleanout adapter on top of the Tee.

You could then screw a air inlet valve (studor vent) into the top of the Tee to make the vent. The AAV also serves as the cleanout cap.

Run the main vent off the second tap on the holding tank.

[Pig Daddy]

Thanks LazyPup.
I really do appreciate your patience with me.

OK, I see what you mean about the back-to-back vent/drain. I also understand no threads on the vent line. But the problem with using the other holding tank ABS fitting to run my vent line from is that it is a 1-1/2" MIPT. So that puts me back in the threaded vent fitting situation again.

What I propose to do now is cut out the offending back-to-back double sanitary tee and plumb it like so. Will this be acceptable?
Grey lines will be new work:

[Pig Daddy]

Can anybody tell me if the above plan is acceptable?
Thanks.

Pig Daddy

[LazyPup]

It really would depend upon the inspector. As I stated before the codes are very vague on campers, boats, motorhomes or mobile mounted systems such as you are building. Normally they require the main vent to come directly off the holding tank, but again, it is a judgement call by your inspector.

On the upside, normally if the system meets code compliance at the point of manufacture it is okay to go anywhere.

If your already set up that way i would try it. You could always add a vent line directly off the second tap on the tank later if need by.