(1) Every individual anti-siphon pipe shall be connected to the soil-pipe or waste-pipe which it serves on the outlet side of the trap obliquely in the direction of flow of the last-mentioned pipe at a point not less than 75 millimetres or more than 750 millimetres from the crown of the trap.

(2) Such anti-siphon pipe shall be carried up independently to discharge into open air in accordance with the requirements of subsection (1) of section 40, or such anti-siphon pipe shall be connected to a common anti-siphon pipe at a point not less than 150 millimetres above the top of the fitting which such anti-siphon pipe serves.

(3) The common anti-siphon pipe either shall discharge into the open air in accordance with the requirements of subsection(1) of section 40, or it may be connected to the main vent in accordance with the requirements of section 42.