Hong Kong Regulations

BUILDING (STANDARDS OF SANITARY FITMENTS, PLUMBING, DRAINAGE WORKS AND LATRINES) REGULATIONS - REGULATION 31

Ventilating pipes

(1) Every ventilating pipe for any drain or sewer shall be carried up to a
height not less than 1 m above the roof of the building to which it is fixed
or, where such building has a pitched roof, above the eaves of such building.
(L.N. 294 of 1976)

(2) No ventilating pipe shall be so fixed as to permit the escape of foul air
from any drain, sewer, soil pipe or waste pipe into any building.

(3) Soil pipes or waste pipes may be carried up to a suitable height above the
building to which they are fixed to act as ventilating pipes for any drain or
sewer.

(4) The internal diameter of every ventilating pipe and of every soil pipe or
waste pipe which, under paragraph (3), is acting as a ventilating pipe, shall
be not less than 80 mm. (L.N. 294 of 1976)

(5) The open end of every ventilating pipe shall be provided with a suitable
grating having apertures of an aggregate area not less than the sectional area
of the pipe.

(6) Ventilating pipes shall not be used for the carriage of surface  water.