Wet Vent


Definitions:

Wet vent means a waste pipe that also serves as a vent pipe.


There are two types of fixtures in a wet vent installation:

wet venting fixture and wet vented fixture.


wet vent


7.5.7.1.(1) :

there may be up to three fixtures installed in a wet vent group:


  1. one fixture is wet venting,
  2. one or two fixtures are wet venting.


7.5.7.1.(1)(b):


Only the wet vented fixture is a water closet
or other fixture using a siphonic trap


Installation Requirements:


  1. All the fixtures must be located at the same floor.
  2. Wet vent must connect to the horizontal waste pipe of P-trapped wet vented fixture


lavatory_showerstall.png


Wet vent cannot connect to the vertical waste pipe of a P-trapped fixture

  1. 7.5.7.1.(1) (c):

wet vent  must be installed 450 mm minimum or 1500 mm maximum downstream from weir
of a P-trapped wet vented fixture.


max_min


  1. 7.5.5.2.(3):

Wet vent is not required to be connected above the horizontal
center line of the soil or waste pipe


connection1

connection2


  1. wet vent may connect to either vertical or horizontal waste pipe of a wet vented siphonic trap.


S-trap connection1

S-trap connection


There are no limits placed on how close a
wet vent may connect to a siphonic fixture


  however



Wet vent must be located within 1500 mm of the elbow serving a water closet or any floor mounted siphonic fixture


1500mm
  1. 7.5.7.1.(1)(d):

At least one of the wet venting fixtures must be drained through a continuous waste and vent


gradient


  1.  
  1. If two wet venting fixtures connect to the wet vent at the same level, the wet venting fixtures must be dual vented.


dual


  1. If two wet venting fixtures connect to the wet vent not at the same level, they must be separately vented with one of the fixtures drained through a continuous waste and vent.


separate


  1.  
There are no limits placed on the developed length of a wet vent


Sizing Wet Vent:


7.5.7.1.(1)(d):

The minimum size of a wet vent is determined by the size of the wet venting fixture trap


Trap, in
min Wet Vent, in

1 1/4, 1 1/2

1 1/4

2

1 1/2

3, 4, 6

2


1connection

2connection

3connection


The vertical extensions of a wet vents above the wet venting fixture connection is sized as a branch vent according to Table 7.5.7.2.A..


sizing1

sizing2