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.
Different fixtures have different load ratings. For example, in the Uniform Plumbing Code in a private (non-public) building on a 1.5" vent line you can have 4 bathtubs or 2 clothes washers or 16 drinking fountains...
Not greater than 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.
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.
Can my toilet and sink share the same vent? Yes, the toilet and sink can share the same vent, as can the shower.
Every plumbing fixture needs to have a vent to work properly. Bath tubs, toilets, washing machines and kitchen sinks need the biggest plumbing vents.
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.
Tips for Installing Vent Pipes
When installing a revent pipe, the horizontal portion must be at least 6 inches above the fixture's flood level or to the highest point water can rise. For example, the flood level for a sink is its rim or overflow hole.
The dry-vent connection to the vertical wet vent shall be an individual or common vent serving one or two fixtures.
A single 2" line can vent 24 fixture units. A private toilet is 3 fixture units so you have plenty of available space. But it is not legal as drawn. Vents cannot combine until 6" above flood level.
Vent pipes shall be not less than 11/4 inches (32 mm) in diameter. Vents exceeding 40 feet (12 192 mm) in developed length shall be increased by one nominal pipe size for the entire developed length of the vent pipe.
Simply follow the AAV's guidelines. For example, Studor's Mini-Vent can vent three DFUs on a 11/2-inch line (that's the maximum DFUs you are allowed on that horizontal branch by code) and six DFUs on a 2-inch line (again, the maximum amount of DFUs allowed by code on that horizontal branch).
It depends on the distance between each plumbing. If they are too close to each other, they can share. If they are away from each other, vents are separated.
All municipalities have different requirements, but some do not draw a hard line on requiring exhaust fans. Bathroom ventilation is needed in those areas, but it can be from a window or fan—you choose. Building code is a model code that each community can adopt and adapt according to its needs.
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.
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.
Some types of broken ventilation can even actively suck up sewer gas and release it through your sink drain or toilet bowl. When this happens, stinky sewer gas will enter your home.
Venting is necessary for bathroom plumbing systems to prevent blockage. All pipes in your home, particularly for toilets, sinks, and showers, require proper venting. It protects the trap on the drain pipe. In addition, it helps you secure your wallet, fittings, time, and even the pipe itself.
In general, the vent should be as close as possible to the fixtures it serves. This proximity helps ensure the vent can effectively equalize air pressure and prevent sewer gas entry. However, there are some common guidelines to consider: The vent should be within 5 to 6 feet of the fixture drain it serves.
No problem--a 2" horizontal drain line is good for up to 8 fixture units (not 8 individual fixtures--8 fixture units). A shower is counted as 2 FU, each sink is 1 FU.
Toilet Vent Pipe Size? It's typically recommended that you go with a 2" PVC pipe for the vent. This is according to the uniform plumbing code (UPC).