7.5.7.5 — Yoke Vents

(1) Except as provided in Sentence (4), where a soil or waste stack receives the discharge from fixtures located on more than 11 storeys, a yoke vent shall be, (a) installed for each section of 5 storeys or part of them counted from the top down, (b) installed at or immediately above each offset or double offset, and (c) sized in accordance with Sentence 7.5.7.5. (1). (2) The yoke vent shall be connected to the soil or waste stack by means of a drainage fitting at or immediately below the lowest soil or waste pipe from the lowest storey of the sections described in Sentence (1). (3) The yoke vent shall connect to the vent stack at least 1 000 mm above the floor level of the lowest storey in the section described in Sentence (1). (4) A yoke vent need not be installed provided the soil or waste stack is interconnected with the vent stack in each storey of the section in which fixtures are located by means of a vent pipe equal in size to the branch or fixture drain or 2 in. in size, whichever is smaller.