IPC Vent Question

[JCsPlumbing]

I get myself confused venting DWV sometimes. Can you wet vent a whirlpool tub and separate shower with a single lavatory? Do you need to upsize the lav drains horizontal up to 3"? If so does it have to be 3" vertically through the roof or does only the horizontal branch need be 3"?

Thanks for all input.

J.C.

[Masterplumb]

I get myself confused venting DWV sometimes. Can you wet vent a whirlpool tub and separate shower with a single lavatory? Do you need to upsize the lav drains horizontal up to 3"? If so does it have to be 3" vertically through the roof or does only the horizontal branch need be 3"?

Thanks for all input.

J.C.

NYS code allows to wet vent an entire bathroom group through the lavatory. We must upsize the wet vent to 2", and the V.T.R. always must be 3".

[JCsPlumbing]

But a traditional "bathroom group" is a t/s, lav, w/c. In that group a t/s=shower.

So basically I have a bathroom group with the additon of a whirlpool tub connecting at the lavs horizontal arm just after the shower then picking up the w/c for venting.

Does this overload the wet vent if it's 2"? I was thinking that you can upsize the wet vent to 3" to allow for this but wasn't sure if it must be carried full in size through the roof or was allowed to be 2"?

We are not required to VTR 3".

Thanks.

J.C.

[Masterplumb]

But a traditional "bathroom group" is a t/s, lav, w/c. In that group a t/s=shower.

So basically I have a bathroom group with the additon of a whirlpool tub connecting at the lavs horizontal arm just after the shower then picking up the w/c for venting.

Does this overload the wet vent if it's 2"? I was thinking that you can upsize the wet vent to 3" to allow for this but wasn't sure if it must be carried full in size through the roof or was allowed to be 2"?

We are not required to VTR 3".

Thanks.

J.C.

Your code (whatever it is) should have a venting chart (fixture units).

If you need to be 3" for the wet vent (which I think is not necessary) you would most likely need to stay 3" for entire run.

[biscuit]

From the 2003 IPC

909.1Wet vent permitted. Any combination of fixtures within
two bathroom groups located on the same floor level are permitted
to be vented by a wet vent. The wet vent shall be considered
the vent for the fixtures and shall extend from the
connection of the dry vent along the direction of the flow in the
drain pipe to the most downstream fixture drain connection
the horizontal branch drain. Only the fixtures within the bathroom
groups shall connect to the wet-vented horizontal branch
drain. Any additional fixtures shall discharge downstream of
the wet vent.
909.1.1Verticalwet vent.Any combination of fixtureswithin
two bathroomgroups located on the same floor level is permitted
to be vented by a vertical wet vent. The vertical wet
vent shall extend fromthe connection to the dry vent down to
the lowest fixture drain connection. Each fixture shall connect
independently to the vertical wet vent. Water closet
drains shall connect at the same elevation. Other fixture
drains shall connect above or at the same elevation as the water
closet fixture drains. The dry vent connection to the vertical
wet vent shall be an individual or common vent serving
one or two fixtures.
909.2 Vent connection. The dry vent connection to the wet
vent shall be an individual vent or common vent to the lavatory,
bidet, shower or bathtub. The dry vent shall be sized based on
the largest required diameter of pipe within the wet vent system
served by the dry vent.
909.3 Size. The wet vent shall be of a minimum size as specified
in Table 909.3, based on the fixture unit discharge to the
wet vent.

[DuckButter]

NYS code allows to wet vent an entire bathroom group through the lavatory. We must upsize the wet vent to 2", and the V.T.R. always must be 3".

Exactly the same for MA code.
Any soil stack requires the same size VTR...any residence will have a min 3" stack for toilets.
Wet vents is a minimum 2".
Min size VTR is 2" for loop vents or individual branch vents.

Although we haven't resolved a thing for JC...I don't think either codes are ipc.