Hong Kong Regulations

BUILDING (STANDARDS OF SANITARY FITMENTS, PLUMBING, DRAINAGE WORKS AND LATRINES) REGULATIONS - REGULATION 58

Gullies

(1) Open trapped gullies shall be covered with a suitable grating having
openings equal to an area not less than the cross sectional area of the outlet
of the trap.

(2) Where sealed trapped gullies are used, adequate provision shall be made
for the ventilation of the space above the water level of the trap.