4. Wet venting.

Question 0

3. Size of combination of drain and vent pipe.
Diameter of pipe - FU of horizontal branch or stack - FU of building drain.
2" - ? - ?
2-1/2" - ? - ?
3" - ? - ?
4" - ? - ?
5" - ? - ?
6" - ? - ?

Answer 0

2" - 3 - 4
2-1/2" - 6 - 26.
3" - 12 - 31.
4" - 20 - 50.
5" - 160 - 250.
6" - 360 - 575.

Question 1

4. What can be wet vented?

Answer 1

Any combination of fixtures within one bathroom group located in the same room. Only the fixtures within the bathroom group shall connect to the wet-vented horizontal branch drain.

Question 2

5. Slope of combination waste and vent system.

Answer 2

The horizontal combination drain and vent pipe shall have a maximum slope of one-half unit vertical in 12 units horizontal ( 4-percent slope, 1/2” per foot). The minimum slope shall be in accordance with Table 704.1.

Question 3

6. Connection of combination drain and vent system.

Answer 3

It shall be provided with a dry vent connected at any point within the system or the system shall connect to a horizontal drain that is vented in accordance with one of the venting methods specified in this chapter. Combination drain and vent systems connecting to building drains receiving only the discharge from a stack or stacks shall be provided with a dry vent. The vent connection to the combination drain and vent pipe shall extend vertically a minimum of 6 inches above the flood level rim of the highest fixture being vented before offsetting horizontally.