Section 58(5) in Faridabad Complex Administration Building Rules, 1989
(5)Where the water-closet discharges into a soil pipe which also receives the discharge from another water-closet the trap of the water-closet shall be ventilated by a pipe, which shall :-(a)have an internal diameter of not less than 50 millimetre;(b)be connected with the arm of the soil pipe at a point not less than 7.5 centimetre and not more than 30 centimetres from the highest part of the trap, on that side of water seal which is nearer to the soil pipe and in the direction of the flow; and(c)either have an open and as high as the top of the soil pipe or be carried into a soil pipe at a point not less than 2.0 metre above the highest connection to the soil pipe.
