Hong Kong Regulations

BUILDING (STANDARDS OF SANITARY FITMENTS, PLUMBING, DRAINAGE WORKS AND LATRINES) REGULATIONS - REGULATION 32

Rain water pipes

(1) (a) Every rain water pipe which discharges to a drain which is connected
to a public sewer provided for the carriage of surface  water shall-

        (i)    in the case of a rain water pipe situated outside a building,
               discharge either not more than 150 mm above the level of the
               ground over a suitably trapped gully or into a trapped gully
               below the level of the grating but above the level of the water
               in the trap; and

        (ii)   in the case of a rain water pipe situated inside a building

(other than a rain water pipe used solely for the conveyance of rain water
from a roof), be properly trapped with an efficient trap which shall be so
formed and fixed as to maintain a water seal of not less than 75 mm. (L.N. 62
of 1966; L.N. 361 of 1980)

   (b)  Every rain water pipe which discharges to a channel shall discharge at
        a height not more than 150 mm above the level of the top of the
        channel.

   (c)  Every rain water pipe which discharges, through a cast iron conductor,
        to the side channel in a street shall be provided, at the foot
        thereof, with a shoe so as to ensure that any surface water discharged
        from the pipe will discharge directly into the conductor.

(2) The number and size of rain water pipes provided for any building shall be
calculated at the rate of 700 square millimetres of pipe to every 10 square
metres of horizontal roofed-over surface.

(3) Save as provided in regulation 33, the diameter of every rain  water pipe
shall be not less than 65 mm.

(4) Rain water pipes shall not be connected with any soil pipe, waste pipe or
ventilating pipe.

(5) Where a rain water pipe discharges, across any footpath, to the side
channel of a street, it shall discharge through a cast iron conductor. (L.N.
294 of 1976)