A horizontal wet vent could have as few as two fixtures or as many as ten fixtures but not more than two fixtures of any type can be connected to the system. Each wet vented fixture drain shall connect independently to the horizontal wet vent.
Under the Uniform Plumbing Code, a 2" vent can handle 24 fixture units(F.U). In a residence, a lavatory sink= 1.0 F.U., bathtub/shower= 2.0 F.U. and a toilet 1.6 gallon or less= 3.0 F.U, greater than 1.6 gallon= 4.0 F.U. So, 3-lav sinks, 3-1.6 toilets and 3-tubs/showers could be on one 2" vent.
Wet venting is limited to vertical drainage piping receiving the discharge from the trap arm of one and two fixture unit fixtures that also serves as a vent not exceeding four fixtures.
IPC allows any combination of fixtures from two bathroom groups to be wet vented, ie two each of WCs, lavs, bathing fixtures, bidets, and floor drains.
Circuit venting involves up to eight fixtures and a single vent. A dry vent connects between the two most upstream fixture drains (trap arms) on the horizontal branch.
An individual vent is permitted to vent two traps or trapped fixtures as a common vent. The traps or trapped fixtures being common vented shall be located on the same floor level.
The circuit vent shall be not less than 2 inches (50mm) in diameter, and the connection shall be located between the two most upstream fixture drains. The vent shall connect to the horizontal branch on the vertical. The circuit vent pipe shall not receive the discharge of soil or waste.
If there are two bathrooms that are adjacent to one another or a bathroom that has a separate water closet (WC), wet venting is acceptable so long as both are at the same elevation. However, when bathrooms are on two different floors of the home, even if one is directly above the other, using a wet vent is not allowed.
Well, you can't! You'd often blow air from one bathroom into the other, and local building inspectors wouldn't approve it. But while you can't have two fans with one vent, you can make one fan and one vent serve two bathrooms. This setup requires an in-line exhaust fan.
Any combination of fixtures within two bathroom groups located on the same floor level is permitted to be vented by a vertical wet vent. The vertical wet vent shall be considered the vent for the fixtures and shall extend from the connection of the dry vent down to the lowest fixture drain connection.
The wet vent shall be sized based on the fixture unit discharge into the wet vent. The wet vent shall be not less than 2 inches (50 mm) in diameter for 4 drainage fixture units (dfu) or less, and not less than 3 inches (80 mm) in diameter for 5 dfu or more.
“Be mindful of venting too often.”
“Prolonged or repeated venting can become unproductive,” says Firdaus S. Dhabhar, Ph. D., a professor at the University of Miami Miller School of Medicine's Department of Psychiatry, Department of Microbiology and Immunology, and Sylvester Comprehensive Cancer Center.
Disadvantages: the heat consumption of the wet process is too high, usually between 5234-6490 J/kg and the consumption of ball mill vulnerable parts is also large.
The maximum allowable fixture unit rating through a 2-in. wet vent is three. The most downstream fixture is the water closet. A water closet is four fixture units as per Table 7.4.
A BATHROOM GROUP LOCATED ON THE SAME FLOOR LEVEL MAY BE VENTED BY A HORIZONTAL WET VENT - THE LENGTH OF THE TRAP ARM MUST NOT EXCEED THE LIMITS OF TABLE 1002.2. - THE WATER CLOSET FIXTURE DRAIN CONNECTION MUST BE DOWNSTREAM OF ALL FIXTURE DRAIN CONNECTIONS TO THE HORIZONTAL WET VENT.
Can my toilet and sink share the same vent? Yes, the toilet and sink can share the same vent, as can the shower.
A horizontal wet vent could have as few as two fixtures or as many as ten fixtures but not more than two fixtures of any type can be connected to the system. Each wet vented fixture drain shall connect independently to the horizontal wet vent.
Yes you can run two vents off of it however you will naturally get less volume through each one, if balanced evenly you will get about 50 CFM through each for a total of 100 CFM.
To fulfill the local exhaust airflow requirements of ASHRAE 62.2 (2010) and the International Residential Code (IRC 2021, Section M1507), bathroom fans should have a mechanical exhaust capacity of ≥ 50 cfm for intermittent operation or ≥ 20 cfm of ventilation when operated continuously.
Trap Arm / Fixture Drain (shower): Distance is limited by the diameter of the pipe as the fall cannot exceed the pipe diameter. If 2" the distance would be 8' measured from the connection to the wet vent (where blue meets green).
A dry vent is a pipe design that uses a separate pipe for air to escape. Water never flows through your pipes with this type of vent. However, wet vents manage air and water, and they do so for different fixtures. They're typically used in bathrooms with limited space and high-capacity plumbing needs.
Plumbing vent pipes are meant to be straight and vertical. Under no circumstances should a plumbing vent pipe be installed with a 90 degree angle PVC joint. Any angles should be limited to one 45-degree angle from horizontal pipe if the pipe needs assistance running through the attic and up through the roof.
A combination of fixtures located on the same floor level shall be permitted to be vented by a vertical wet vent. The vertical wet vent shall be considered to be the vent for the fixtures and shall extend from the connection of the dry vent down to the lowest fixture drain connection.
A maximum of eight fixtures connected to a horizontal branch drain shall be permitted to be circuit vented. Each fixture drain shall connect horizontally to the horizontal branch being circuit vented.