The Ontario Building Code | Branch Vents, Headers, Continuous Vents and Circuit Vents

7.5.8.3. Branch vents, Headers, Continuous vents and circuit Vents

(1) Branch vents, headers, circuit vents and continuous vents shall be sized in accordance with Table 7.5.8.3., unless they are individual vents or dual vents.

Table 7.5.8.3.
Sizing of Branch vents, Headers, Continuous vents and circuit Vents

Forming Part of Article 7.5.8.3.

Item	Column 1	Column 2	Column 3	Column 4	Column 5	Column 6	Column 7	Column 8	Column 9
	Total Hydraulic Load Served by vent, fixture units	Size of vent pipe, in.
		1 ¼	1 ½	2	3	4	5	6	8
		Maximum Length of vent pipe, m(1)(2)
1.	2	9	NL	NL	NL	NL	NL	NL	NL
2.	8	9	30	61	NL	NL	NL	NL	NL
3.	20	7.5	15	46	NL	NL	NL	NL	NL
4.	24	4.5	9	30	NL	NL	NL	NL	NL
5.	42	NP	9	30	NL	NL	NL	NL	NL
6.	60	NP	4.5	15	120	NL	NL	NL	NL
7.	100	NP	NP	11	79	305	NL	NL	NL
8.	200	NP	NP	9	76	275	NL	NL	NL
9.	500	NP	NP	6	55	215	NL	NL	NL
10.	1 100	NP	NP	NP	15	61	215	NL	NL
11.	1 900	NP	NP	NP	6	21	61	215	NL
12.	2 200	NP	NP	NP	NP	9	27	105	335
13.	3 600	NP	NP	NP	NP	7.5	18	76	245
14.	5 600	NP	NP	NP	NP	NP	7.5	18	76

Notes to Table 7.5.8.3.:

⁽¹⁾NL means not limited.

⁽²⁾NP means not permitted.

(2) For the purposes of Table 7.5.8.3., the length of a branch vent shall be its developed length from the most distant soil or waste pipe connection to a vent stack, stack vent, headeror open air.

(3) For the purposes of Table 7.5.8.3., the length of a header shall be its developed lengthfrom the most distant soil or waste pipe connection to open air.

(4) For the purposes of Table 7.5.8.3., the length of a circuit vent shall be its developed length from the horizontal soil or waste pipe connection to a vent stack, stack vent, headeror open air.

(5) For the purposes of Table 7.5.8.3., the length of a continuous vent shall be its developed length from the vertical soil or waste pipe connection to a vent stack, stack vent, headeror open air.