656695-1890-Bye-Laws-Public-Health-Ordinance-1887 — Page 6

1042

THE HONGKONG GOVERNMENT GAZETTE, 18TH OCTOBER, 1890.

Fall to drains and flush.

Change of direction.

Drains under buildings, &c.

Inlets.

Size of openings in grat- ings.

Traps.

Traps.

Traps.

Form of Traps.

Ventilation.

16. Whenever the gradient of any portion of a drain is less than one in thirty, the Sanitary Board may in its discretion require an automatic flush tank or any other suitable contrivance for attaining an effective flush to be used.

17. All changes of direction in house-drains shall be made by means of properly curved pipes or by half channels in manholes and between the points at which any change of direction occurs all house-drains shall be laid in straight lines and regular grades from point to point.

NOTE. (Inasmuch as changes of direction are the points at which obstructions most frequently occur, and for the purpose of removing obstructions generally, house-holders will do well to provide, at each change of direc- tion, a manhole, giving access to the drain. For this purpose the manhole should be made 3′ 0′′ x 1′ 6′′ to the surface or to a depth of five feet above the drain. Beyond this depth the manhole may be narrowed to l′ 6′′ × 1′ 6′′). But such manhole should not be found in cook-houses or in places where they may be opened and used as receptacles for the disposal of solid rubbish.

18. 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, whenever possible, be laid in one straight line for the whole distance beneath such building, and shall be imbedded and incased throughout its entire length in four inches of good concrete.

Whenever 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.

The stones composing the matrix of the concrete in both cases shall be of a size to pass through a half-inch ring.

19. No new drain shall be constructed in such manner as to allow any inlet to such drain to be placed inside any building on such premises.

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 11⁄2 inches.

NOTE. The object of this is to secure an efficient flush.

21. Traps or gulleys for the removal of rain-water shall be provided with gratings having the nett 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.

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 trap 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 new 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 and 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 remove by flushing.

25. Every main house-train, wherever practicable, shall be ventilated at its upper end by an opening, in free communication with the outer air. This opening shall be placed in such a position, as to render any emanations from it as little obnoxious as possible.

NOTE. (This is, in most cases, to be done by carrying up a well-jointed pipe, not less than four inches in clear internal diameter, to some point, above the eaves of the building, which is not in close proximity to any window or chimney. In the case of rural or suburban tenements, the ventilating opening may be provided on any eminence, or open space at a distance from the dwelling; the ventilating pipe and opening, in this case, being not less than four inches in internal diameter.)