(1)
Except as provided in Sentence (3), the upper end of every vent pipe that is not terminated in open air shall be connected to a venting system that terminates through a roof to open air.
(2)
The upper end of every vent pipe that is terminated in open air, other than a vent pipe that serves an oil interceptor or a fresh air inlet, shall be extended above the roof.
(3)
A vent pipe is permitted to be erected outside a building, provided that
(a)
no single change of direction of the vent pipe exceeds 45°,
(b)
all parts of the vent pipe are nominally vertical,
(c)
in areas where the vent pipe may be subject to frost closure, it is increased to not less than NPS 3 before penetrating a wall or roof, and
(d)
where the building is 4 storeys or less in height, the vent pipe terminates above the roof of the building.
(4)
Except for a fresh air inlet, where a vent pipe is terminated in open air, the terminal shall be located
(a)
not less than 1 m above and not less than 3.5 m in any other direction from every air inlet, openable window or door,
(b)
not less than 2 m above and not less than 3.5 m in any other direction from a roof that supports an occupancy,
(c)
not less than 2 m above ground, and
(d)
not less than 1.8 m from every property line.
(5)
Where a vent pipe passes through a roof, it shall
(a)
be terminated high enough to prevent the entry of roof drainage but not less than 150 mm above the roof or above the surface of storm water, which could pond on the roof, and
(b)
be provided with flashing to prevent the entry of water between the vent pipe and the roof. (See Article 7.2.10.14.)
(6)
Where a vent pipe passes through a roof and may be subject to frost closure, it shall be protected from frost closure by
(a)
increasing its diameter at least one NPS, but not less than NPS 3, immediately before it penetrates the roof,
(b)
insulating the pipe, or
(c)
protecting it in some other manner. (See Article 7.3.4.7.)
(7)
Where a vent pipe is located 2 m or more above a roof, it shall be so constructed as to be stable and secure.
(8)
Flashing shall be of material specified in Article 7.2.10.14. and on a shingled roof shall have a minimum dimension of 500 mm by 500 mm.
(9)
Where a sleeve flashing is installed on a flat roof, it shall extend at least 150 mm above the flood level and on a sloped roof shall be at least 150 mm high on the short side.
(10)
No bore of a vent stack or stack vent shall be reduced or obstructed by the installation of a flashing.