926
No. 10.] THE ORDINANCES OF HONGKONG: [A.D. 1901,
drain at upper opening shall be placed in such a position as to render any emanations from it as little obnoxious as possible.
end.
Ventilation of main house-drain at lower end.
Exception as to ventilation of drain leading from single trap and not more than 60 ft. long.
Fixing of ventilating and fall pipes.
Construction and fixing of down-pipe for rain water.
Construction of waste-pipe
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.
26.-(1.) Every main house-drain shall have a ventilating-opening near to its lower end, and no trap or other obstruction to the free circulation of air shall exist between this opening and the one described in the last preceding By-Law.
(2.) If there is a trap between the house-drain and the public sewer, then an opening shall be made on the house-side of the trap, and the said opening shall be so arranged as to give access to the trap for inspection, cleansing, or repair.
(3.) If there is no trap between the public sewer and the house drain, no special opening need be provided at the lower end.
27. Drains leading from a single trap, and not being more than sixty feet long, need not be provided with an elevated ventilating-opening at their upper end; but, if this is omitted, they shall be provided with a trap, disconnecting them from the public sewer, and shall have a ventilating-opening at the lower end on the house-side of the trap.
28. Ventilating and fall pipes of stoneware shall be securely fixed to the exterior surfaces of walls with wrought-iron bands fitted round the pipe and made fast to the wall with two wrought-iron spikes not less than four inches long. Metal pipes shall also be fixed as above or shall have two ears fixed to them and secured to the wall with two wrought iron spikes not less than four inches long.
29. Down-pipes, conveying rain-water from roofs, shall be constructed of cast or welded wrought iron, and when the down-pipe discharges into the house-drain it shall be completely disconnected therefrom, as described in By-Law 31, and fitted with a bend, shoe, or pedestal pipe. Wherever practicable, the rain-water down-pipes on the street side of buildings shall be carried under the footpath and discharge into the side-channel.
NOTE. - It is most important that such pipes should be completely disconnected from the sewers, so that they cannot by any possibility serve as conduits for conducting sewer air up and into the dwelling.
30. Waste-pipes from baths, sinks, and other similar appliances on the upper floors of buildings shall be of cast-iron socketed pipes or wrought-iron welded pipes, with screwed joints coated with bituminous composition, or in the case of wrought-iron, galvanized, or of well-glazed stoneware socketed pipes, or other approved materials, securely fixed outside the wall, and provided, at each point of connexion, with a suitable head, and at their lower