1. A. Length of Vent Stacks. The length of the vent stack or main vent shall be its developed length from the lowest connection of the vent system with the soil stack, waste stack, or building drain to the vent stack terminal, if it terminates separately, or to the connection of the vent stack with the stack vent, plus the developed length of the stack-vent from the connection to the terminal, if the two vents are connected together with a single extension.
2. B. Size of Stack-Vents, Vent Stacks, Relief Vents, Individual Vents or Branch Vents. The diameter of a stack-vent, vent stack, relief vent, individual vent or branch vent shall not be less than one-half of the diameter of the drain served, but in no case less than 1 1/4 inches, and shall be determined from its length and the total of fixture units connected thereto, as provided in Table 937.B of this code. All water closets vents shall be a minimum of 2 inches in diameter. This shall not be interpreted to allow the alteration or elimination of the need for at least one 3-inch vent stack or stack vent on the building drain as required under §905.C.1 of this code.

3. C. Size of Battery Vents. The diameter of a battery vent shall be not less than one-half the pipe size of the horizontal waste line it is venting, but in no case less than 1 1/2 inches, and shall be determined from its length and the total of fixture units connected thereto, as provided in Table 937.C of this code. The diameter and horizontal length of a battery vent shall in no case be less than permitted in Table 937.C of this code. (See §925 of this code).

   Table 937.B Maximum Length of Vents (ft) (Other than Battery Vents) (See Table 937.C of this Code for Battery Venting)
   Size of Soil or Waste Stack (in)	Fixture Units Connected	Diameter of Vent Required (in)
   		1 1/4	1 1/2	2	2 1/2	3	4	5	6	8
   1 ¼	2	30 ft	-	-	-	-	-	-	-	-
   1 ½	8	50 ft	150 ft	-	-	-	-	-	-	-
   1 ½	10	30 ft	100 ft	-	-	-	-	-	-	-
   2	12	30 ft	75 ft	200 ft	-	-	-	-	-	-
   2	20	26 ft	50 ft	150 ft	-	-	-	-	-	-
   2 ½	42	-	30 ft	100 ft	300 ft	-	-	-	-	-
   3	10	-	30 ft	100 ft	200 ft	600 ft	-	-	-	-
   3	30	-	-	60 ft	200 ft	500 ft	-	-	-	-
   3	60	-	-	50 ft	80 ft	400 ft	-	-	-	-
   4	100	-	-	35 ft	100 ft	260 ft	1000 ft	-	-	-
   4	200	-	-	30 ft	90 ft	250 ft	900 ft	-	-	-
   4	500	-	-	20 ft	70 ft	180 ft	700 ft	-	-	-
   5	200	-	-	-	35 ft	80 ft	350 ft	1000 ft	-	-
   5	500	-	-	-	30 ft	70 ft	300 ft	900 ft	-	-
   5	1100	-	-	-	20 ft	50 ft	200 ft	700 ft	-	-
   6	350	-	-	-	25 ft	50 ft	200 ft	400 ft	1300 ft	-
   6	620	-	-	-	15 ft	30 ft	125 ft	300 ft	1100 ft	-
   6	960	-	-	-	-	24 ft	100 ft	250 ft	1000 ft	-
   6	1900	-	-	-	-	20 ft	70 ft	200 ft	700 ft	-
   8	600	-	-	-	-	-	50 ft	150 ft	500 ft	1300 ft
   8	1400	-	-	-	-	-	40 ft	100 ft	400 ft	1200 ft
   8	2200	-	-	-	-	-	30 ft	80 ft	350 ft	1100 ft
   8	3600	-	-	-	-	-	25 ft	60 ft	250 ft	800 ft
   10	1000	-	-	-	-	-	-	75 ft	125 ft	1000 ft
   10	2500	-	-	-	-	-	-	50 ft	100 ft	500 ft
   10	3800	-	-	-	-	-	-	30 ft	80 ft	350 ft
   10	5600	-	-	-	-	-	-	25 ft	60 ft	250 ft

   Table 937.C Battery Vent Sizing Table Maximum Horizontal Length (ft)
   Soil or waste pipe diam. (in)	Maximum no. Fixture units	Diameter of circuit or loop vent (in)
   		1 1/2	2	2 1/2	3	4	5
   2	3	15 ft	40 ft	-	-	-	-
   2 1/2	6	10 ft	30 ft	-	-	-	-
   3	10	-	20 ft	40 ft	100 ft	-	-
   4	80	-	7 ft	20 ft	52 ft	200 ft	-
   5	180	-	-	-	16 ft	70 ft	200 ft

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 38:2866 (November 2012).