S.L. 10.11 Art. 20Openings.

(1) All drains shall be provided with two untrapped openings. One opening shall communicate with the drain by means of a suitable pipe through an inspection chamber and shall be situated as near as may be practicable to the trap fixed between the drain and the sewer or cesspit, but always on the side of the trap which is nearer to the building. The second opening shall be obtained by carrying up a pipe from the other end of the drain vertically to such a height and in such a manner as may be ordered by the Sanitary Authority.

(2) The opening, which is situated near the intercepting trap, shall be furnished with a grating or other suitable cover so constructed and fitted as to secure the free passage of air through such grating or cover by means of a sufficient number of apertures of which the aggregate extent shall not be less than the sectional area of the pipe or drain to which such grating or cover may be fitted.