Is my venting adequate for what I have

[ngen33r]

I am preparing to redo my basement bathroom and I am not sure if the existing venting is proper for my installation. I have made a rough schematic of the system and will also try to verbally describe it.

I have a 3in vent stack at the far end of the system in a ranch. All fixtures come after this vent and flow through a ~30' 3in PVC trunk in the basement ceiling with a 1/4"-foot pitch. This pipe does a 90 to the floor and expands to 4in PVC and eventually to 5in clay

Fixures that feed the 3in PVC

Bathroom - 6 DFU
Toilet - 3in
Sink - 1.5in
Shower - 2in

Kitchen Sink - 2 DFU

This gives me 8 DFU going down the stack which I think can handle a max of 12 DFU for a wet vent 24 DFU if not venting.

Fixtures that feed the 4in PVC

10 DFU from the first floor

Bathroom - 6 DFU
Toilet - 3in
Sink - 1.5in
Shower - 2in

Bar Sink - 1 DFU

Is my existing configuration acceptable? If I was to add a 2nd bathroom (vented) and a dishwasher on the first floor will I be over the DFU limits for the existing configuration to stay vented? That bumps me up to 16 DFU in the 3in PVC but 6 of those would already be vented.

It does seem like I am violating the following:
908.3
909.1

 

[Stuff]

Nothing there is properly vented. Assume all fixtures have S-traps. You need to get some books on plumbing basics. You are going to have to open up walls to fix things properly.

 

[Sponsor]

 

[hj]

Proper piping installation is MUCH more important than the fixture units, and your drawing, if accurate, does NOT show ANY proper piping.

 

[Terry]

Wet venting is only for bathroom fixtures located on the same floor.
A toilet can't go past a shower or tub.

 

[ngen33r]

Thank You all for the advice so far. The house was built in the 50's so I am trying to fix all of the mistakes that have been done over the years. All of the fixtures do have P traps, I checked last night.

HJ can you expand on your statement. Is it really necessary to tear out all of the PVC and redo everything? Aside from adding proper vents, I do not understand why the main lines are bad. I did not add all the bends to the fixtures in the schematic, just the sizes and locations of the lines that go to the main 3in horizontal run.

Terry does that only apply to venting or does that always apply. The first floor bathroom the toilet drains to the stack right behind the 3in dry vent
and everything else comes after that.

Is the 3in vent right now only technically venting the toilet and the horizontal run?

Assuming my main lines are ok and the toilet can come first with additional venting, what I gather is I need to tear the bathroom wall out and add a vent to the lav drain and shower drain and tie those into the 3in stack going to the roof. Since a wet vent cannot serve a kitchen sink, I will have to cut the kitchen wall and add a line going to the roof there as well. The basement toilet can share the dry vent with the kitchen sink. I will get some actual pictures of the system. It is frustrating knowing that this wasn't done properly when the previous owner had the plumbing redone.

 

[ngen33r]

I have been googling like mad. This is where things get confusing. Looking that this image, it would appear that my bathroom group is acceptably vented (not the rest of the system).

 

[hj]

Whoever drew that system did NOT know the dynamics of wet venting. AS SOON AS the toilets were connected, ANY additional connections DID need individual vents. The "wet venting" ended AT THE TOILETS. Of course, that drawing is from the IPC, which is NOT much a code as far as proper procedures are concerned.

 

[ngen33r]

This is why I need you guys, the net although helpful it is full of bad information. I just want it to be up to code and make sure to prevent trap siphons, while allowing for future expansion. So it is confirmed my 3in vent pipe technically vents only the toilet, what a "waste".

 

[Stuff]

The 3" vent at the toilet is horizontal "dry" below flood level so it is not to code either. Assume everything needs redone as splicing/fixing individual pieces is harder.

 

[Stuff]

Also - a good reference: http://www.co.lincoln.or.us/sites/d..._-_helpful_hints_residential_construction.pdf

 

[ngen33r]

Thanks everyone! So I will start with the basement lines and work backwards through the whole system. I will draw up my schematic for the basement bathroom and have you guys give me the thumbs up or down.

 

[ngen33r]

Here is my first attempt.

 

[Stuff]

A guess from an amateur:

Since there is a wet vent you can not have anything upstream of the toilet. Not even a horizontal dry vent. Vertical dry vent OK.
IPC allows (???) but UPC doesn't allow toilet to drain past wet vented shower.
Lav drain needs to upsize to 2" as providing wet vent for other fixtures.
Lav vent needs upsized to 2" as providing vent for toilet/4" pipe.

 

[Stuff]

I don't see a laundry tub or washing machine standpipe on your lists. Even if you don't have curently it is good to have provisions for a future laundry area.

 

[clix]

Not a plumber, so feel free to ignore.

Is this the layout you have? Couldn't tell from your drawings. If so, it seems the shower is not vented.

 

[ngen33r]

This is my proposal for redoing the system. I always seem to forget about the floor drain. I guess it would not be a bad idea to rough in a drain for the washer while I am at it. The basement bathroom nightmare was tore out so I can start fresh. I assume that a vent for the washer can wet vent the floor drain. The shower will need a wye after the trap to vent since a toilet is up stream?

 

[ngen33r]

Experts chime in. I think this is much closer to what it needs to be. I am not sure about the shower in the basement floor as it will require a wye and a horizontal run to be vented.

EDIT**Reading tells me that a pumped line cannot be wet vented so the floor drain will need a vent after the trap.

I really want to get this figured out so I can have it inspected this weekend.

 

[hj]

If the "laundry" is a washing machine, it cannot 'wet vent' the floor drain.

 

[Cacher_Chick]

Your drawing show problems which may be actual or may just be a bad drawing. Every fixture vent take-off must be vertical until it is at least 6" above the fixture flood rim and no less than 42" above the floor of the highest fixture served by the vent.

It would be helpful for you and for us if you printed off some isometric graph paper and/or made legible isometric drawings. The pipe sizes, the types of fittings used, and their orientation are all important information.

 

[ngen33r]

If the "laundry" is a washing machine, it cannot 'wet vent' the floor drain.

I edited my post after I discovered that.

The stack also cannot vent that toilet since it has waste upstream.

Aside from that is my configuration good? I plan to join the vents up in the floor joists so I will meet the 6in above flood requirement and the 42in floor requirement.