7.5.1.1.Venting for Traps (1) Except as provided in Sentences (2) and (3) and Article 7.5.2.1., every trap shall be vented. (2) A trap that serves a floor drain or hub drain, directly connected to a sanitary building drain is not required to be vented where (a) the size of the trap is at least 3 in., (b) the length of the fixture drain is at least 900 mm, (c) the total fall on the fixture drain does not exceed its inside diameter, and (d) the minimum slope on a 3 in. fixture drain is 1 in 50 and on sizes larger than 3 in. is 1 in 100. (3) A trap is not required to be vented where (a) it serves a subsoil drainage pipe, (b) it serves a storm drainage system, or (c) it forms part of an indirect drainage system, less than three storeys high. Table 7.4.10.5.B. Maximum Load on Vertical Drainage Pipe in GPM and Maximum Length of Vent Stacks Forming Part of Sentences 7.4.10.5.(3), 7.5.3.2.(3) and 7.5.7.2.(1)  Stack
Size,
in. (Drain)

Water
Occupied
Area

Flow
Rate,
gal/min

Vent Stack Size, in. and Maximum Length, metres


1½

2

2½

3

4

5

6

8

10

12

14


3

0.15

18.4

12.8

44.2

108.0

317.0

 

 

 

 

 

 

 


 

.20

29.4

9.8

33.5

82.3

245.4

 

 

 

 

 

 

 


 

.25

43.0

8.2

28.7

70.1

207.3

 

 

 

 

 

 

 


 

.29

55.7

7.6

26.2

64.0

189.0

 

 

 

 

 

 

 


 

.30

58.4

7.3

25.9

62.5

185.9

 

 

 

 

 

 

 


 

.33

69.5

7.0

24.7

61.0

178.3

 

 

 

 

 

 

 


4

0.15

39.6

 

10.7

25.9

76.2

297.2

 

 

 

 

 

 


 

.20

64.0

 

8.2

19.8

59.4

228.6

 

 

 

 

 

 


 

.25

92.5

 

7.0

16.8

50.3

193.5

 

 

 

 

 

 


 

.29

120.0

 

6.4

15.2

45.7

176.8

 

 

 

 

 

 


 

.30

126.0

 

6.1

14.9

44.8

173.7

 

 

 

 

 

 


 

.33

150.0

 

5.8

14.3

42.7

166.1

 

 

 

 

 

 


5

0.15

72.0

 

 

8.5

25.0

97.5

300.2

 

 

 

 

 


 

.20

116.0

 

 

6.4

19.2

74.7

231.6

 

 

 

 

 


 

.25

168.0

 

 

5.5

16.2

63.1

195.1

 

 

 

 

 


 

.29

217.0

 

 

4.9

14.9

57.6

178.3

 

 

 

 

 


 

.30

228.0

 

 

4.9

14.6

56.7

175.3

 

 

 

 

 


 

.33

272.0

 

 

4.6

14.0

54.6

169.2

 

 

 

 

 


6

0.15

117.0

 

 

 

10.1

39.6

121.9

304.8

 

 

 

 


 

.20

189.0

 

 

 

7.9

30.5

94.5

236.2

 

 

 

 


 

.25

274.0

 

 

 

6.7

25.6

79.2

199.6

 

 

 

 


 

.29

354.0

 

 

 

6.1

23.5

73.2

181.4

 

 

 

 


 

.30

370.0

 

 

 

5.8

23.2

71.6

179.8

 

 

 

 


 

.33

441.0

 

 

 

5.8

22.3

68.6

172.2

 

 

 

 


8

0.15

251.0

 

 

 

 

9.4

29.0

73.2

286.5

 

 

 


 

.20

406.0

 

 

 

 

7.3

22.3

56.4

219.5

 

 

 


 

.25

589.0

 

 

 

 

6.1

18.9

47.2

185.9

 

 

 


 

.29

762.0

 

 

 

 

5.5

17.1

42.7

169.2

 

 

 


 

.30

798.0

 

 

 

 

5.5

17.1

42.7

167.6

 

 

 


 

.33

950.0

 

 

 

 

5.2

16.2

41.1

160.0

 

 

 


10

0.15

455.0

 

 

 

 

 

9.4

23.8

93.0

292.6

 

 


 

.20

736.0

 

 

 

 

 

7.3

18.3

71.6

224.0

 

 


 

.25

1070.0

 

 

 

 

 

6.1

15.5

61.0

190.5

 

 


 

.29

1380.0

 

 

 

 

 

5.5

14.0

54.9

173.7

 

 


 

.30

1440.0

 

 

 

 

 

5.5

14.0

54.9

170.7

 

 


 

.33

1730.0

 

 

 

 

 

5.2

13.4

51.8

163.1

 

 


12

0.15

740.0

 

 

 

 

 

 

9.4

36.6

115.8

286.5

 


 

.20

1200.0

 

 

 

 

 

 

7.3

28.7

89.9

219.5

 


 

.25

1730.0

 

 

 

 

 

 

6.1

24.1

76.2

185.9

 


 

.29

2240.0

 

 

 

 

 

 

5.5

21.9

68.6

169.2

 


 

.30

2350.0

 

 

 

 

 

 

5.5

21.6

68.6

167.6

 


 

.33

2800.0

 

 

 

 

 

 

5.2

20.7

65.5

160.0

 


15

0.15

1340.0

 

 

 

 

 

 

 

12.2

38.1

93.0

146.3


 

.20

2170.0

 

 

 

 

 

 

 

9.4

29.3

71.6

112.8


 

.25

3140.0

 

 

 

 

 

 

 

7.9

24.7

61.0

94.5


 

.29

4070.0

 

 

 

 

 

 

 

7.3

22.6

54.9

88.4


 

.30

4260.0

 

 

 

 

 

 

 

7.0

22.3

54.9

85.3


 

.33

5080.0

 

 

 

 

 

 

 

6.7

21.3

51.8

82.3


Col. 1

2

3

4

5

6

7

8

9

10

11

12

13

14 7.5.2.Stack Venting & Modified Stack Venting, Circuit Venting and Relief Venting