Louisiana Administrative Code › Title 51 - PUBLIC HEALTH-SANITARY CODE › Part XIV - Plumbing › Chapter 9 - Vents › Section XIV-919 - Wet Venting

Current through Register Vol. 50, No. 6, June 20, 2024
A.
				Single Bathroom Groups. A single bathroom group of fixtures may be installed
				with the drain from a back vented lavatory serving as a wet vent for a bathtub
				or shower stall and for the water closet, provided that the wet vent is one
				pipe size larger than the upper fixture drain but in no case smaller than the
				lower fixture drain, whichever is the larger, and that both fixture drains
				conform to Table 913.A of this code. No urinal exceeding 2.0 dfu or washing
				machine drain shall discharge into any wet vent. A minor fixture, such as a
				bathtub or shower, shall enter the wet vent/drain pipe upstream of a major
				fixture, such as a water closet [i.e., a minor (having less fixture units)
				over/upstream of a major (having more fixture units) rule]. The dry vent
				servicing the wet vent shall be sized based upon the developed length and the
				total fixture units connected thereto in accord with §937. B and Table 937.B of
				this code. (Note: Per the definition of "wet vent", the wet vent terminates at
				the connection with the water closet's fixture drain. If the water closet is
				being vented by a method other than the wet vent, the wet vent terminates where
				it connects to the stack, the lowest or most downstream fixture drain, or where
				it connects to a separate horizontal branch line or the building drain, as
				appropriate.)
B. Double Bath.
				Bathroom groups back-to-back on the top floor consisting of two bathtubs or
				shower stalls may be installed on the same horizontal branch with a common vent
				for the lavatories with no back vent for the water closets, bathtubs or shower
				stalls, provided that the wet vent is one pipe size larger than the upper
				fixture drain but in no case smaller than the lower fixture drain, whichever is
				the larger, and that both fixture drains conform to Table 913.A of this code.
				No urinal exceeding 2.0 dfu or washing machine drain shall discharge into any
				wet vent. A minor fixture, such as a bathtub or shower, shall enter the wet
				vent/drain pipe upstream of a major fixture, such as a water closet [i.e., a
				minor (having less fixture units) over/upstream of a major (having more fixture
				units) rule]. The dry vent servicing the wet vent shall be sized based upon the
				developed length and the total fixture units connected thereto in accord with
				§937. B and Table 937.B of this code.
NOTE: Per the definition of
wet vent
, the
				  wet vent terminates at the connection with the water closet's fixture drain. If
				  the water closet is being vented by a method other than the wet vent, the wet
				  vent terminates where it connects to the stack, the lowest or most downstream
				  fixture drain, or where it connects to a separate horizontal branch line or the
				  building drain, as appropriate.
C. Multistory Bathroom Groups. On the lower
				floors of a multistory building, the waste pipe from one or two lavatories may
				be used as a wet vent for one or two bathtubs or showers provided that:
1. the wet vent and its extension to the vent
				stack is not less than 2-inch (51 mm) diameter;
2. each water closet below the top floor is
				individually back vented;
3. the
				vent stack is sized in accordance with Table 919.C of this code; and,
4. the lowest wet vent shall be sized for the
				total bathtubs or showers connected to the stack but in no case shall the wet
				or dry portion of the lowest vent be less than required for the vent stack
				itself.
Table 919.C
Size of Vent Stack
Number of Wet Vented Fixtures
Diameter of Vent Stacks (In.)
1 or 2 bathtubs or showers
2
3 to 5 bathtubs or showers
2 1/2
6 to 9 bathtubs or showers
3
10 to 16 bathtubs or showers
4