BUILDING (STANDARDS OF SANITARY FITMENTS, PLUMBING, DRAINAGE WORKS AND LATRINES) REGULATIONS
Traps for soil fitments
(1) Every soil fitment shall be provided with a suitable trap with a water seal of not less than 50 mm.
(2) The internal diameter of every such trap shall be not less than-
(a) 80 mm, in the case of a watercloset fitment, slop sink, or urinal with more than 3 basins or stalls or with a channel longer than 2 m;
(b) 50 mm, in the case of a urinal with more than one and not more than 3 basins or stalls or with a channel not longer than 2 m;
(c) 40 mm, in the case of a bidet or urinal with a single basin or stall; and
(d) 100 mm, in the case of a trough watercloset.