1. A. Horizontal Branches. A horizontal waste branch meeting the following criteria shall effectively provide an exception to the need for a revent pipe(s).

   1. 1. Provided:

      1. a. the horizontal branch is full size throughout its length;
      2. b. each fixture drain enters the horizontal branch via a wye and 1/8th bend or a combination wye and 1/8th bend;
      3. c. the wastes are connected with a pitch of not more than 1/4 inch per foot (21 mm per meter);
      4. d. that a 2-inch "P" trap shall be the minimum for tubs and showers;
      5. e. the waste openings in the horizontal branch shall not be less than 1 1/4 inches for lavatories and 1 1/2 inches for a sink; and,

      6. f. that one drinking fountain shall be considered as one lavatory; then, without the use of reventing:

         1. i. one sink and one lavatory, or one tub, or one shower, or three lavatories within 8 feet (2438 mm) developed length of a main vented line may be installed on a 2-inch horizontal waste branch; or,

         2. ii. two lavatories within 5 feet (1524 mm) developed length of a main vented line may be installed on a 1 1/2-inch horizontal waste branch.

            Figure 923.A

2. B. Where Required. All fixtures discharging downstream from a water closet shall be individually vented.

   Figure 923.BRequired Individual Vents

3. C. Limits of Fixture Units Above Bathtubs and Water Closets. Up to a total of three fixture units may be placed on a soil or waste stack on floors above the highest water closet or bathtub connection without the use of a revent pipe(s) provided:

   1. 1. the soil or waste stack is not less than 3-inch diameter;
   2. 2. the total fixture unit load on the stack does not exceed the limitations of Table 725.A.2 of this code;
   3. 3. the largest fixture drain opening into the stack does not exceed the nominal diameter of the trap of the fixture to be connected except as permitted in §923.A of this code. Such opening for multiple fixture connections shall be limited to use on one floor only;
   4. 4. each fixture above the highest tub or water closet is no farther from the stack than permitted in Table 913.A of this code; and,
   5. 5. all fixtures on lower floors are vented as otherwise required by this Chapter.

Authority Note

AUTHORITY NOTE: Promulgated in accordance with R.S. 40:4(A)(7) and R.S. 40:5(2)(3)(7)(9)(16)(17)(20).

Historical Note

HISTORICAL NOTE: Promulgated by the Department of Health and Hospitals, Office of Public Health, LR 38:2864 (November 2012).