A.D. 1901.]
PUBLIC HEALTH.
[No. 10.
925
foot 6 inches by 1 foot 6 inches. But such manholes should not be found in cook-houses in places where they may be opened and used as receptacles for the disposal of solid rubbish.
18.-(1.) No drain shall be so constructed as to pass under any building, except when any other mode of construction is impracticable. Any drain passing under a building shall (unless the written permission of the Board etc.
soft ground, has first been obtained to lay it otherwise) be laid in one straight line for the whole distance beneath such building, and shall be imbedded, and encased throughout its entire length in four inches of good concrete.
(2.) Where a drain traverses soft or yielding ground, or where water may make its appearance in the trench, the drain shall be surrounded throughout its entire length with four inches of good concrete.
(3.) The stones composing the matrix of the concrete in both cases shall be a size to pass through a half-inch ring.
19. No drain shall be constructed in such manner as to allow any inlet to such drain to be placed inside any building.
20. The aggregate area of the openings in any grating fixed on inlets to waste-pipes from baths or sinks shall not be less than four square inches, and the waste-pipe shall not have a less internal diameter than 1½ inches.
NOTE. The object of this is to secure an efficient flush.
21. Traps or gullies for the removal of rain-water shall be provided with gratings having the net area of the openings not less than twice the area of the trap or pipe. Such gratings shall be sunk to a depth of at least one inch below the surrounding pavement, with a slope round them equal to half the width of the grating.
NOTE.-It is not sufficient to provide pipes of ample diameter; there must be openings of sufficient size to admit the rain to them.
Prohibition of inlet to drain being inside building.
Area of openings in grating on inlet to waste pipe, etc.
Grating to trap or gully for removal of rain water.
Position of trap at inlet to drain.
22. Traps at the inlets to drains shall be placed so that the water-level in them is not less than one foot below the ground, and such traps shall be placed as low down as the level of the house-drain or branch will permit of; provided that the depth be not more than two feet.
23. Traps shall have not less than two inches of water seal and shall be securely fixed to the drain. All stoneware traps shall be surrounded with a thickness of four inches of lime concrete.
24. No person shall construct or fix in connexion with any drain or waste-pipe the form of trap of the kind known as the Bell-trap or any trap of the kind known as the D trap.
All traps connected with any private drains shall be properly set in cement mortar, to the satisfaction of the Board.
NOTE.-Bell-traps and D traps from their form give rise to deposit of filth difficult to move by flushing.
25. Every main house-drain, wherever practicable, shall be ventilated at upper end by an opening in free communication with the outer air. This main house-