466
28
Construction of house
sewers
vested in Sanitary Board.
Quality of pipes and materials.
The objec
use of
indifferent materials.
like a mill-chimney, was the subject of prolonged and heated correspondence, between the Admiral Superintendent, and the Sewerage Authority, the former reiterating complaints of the stenches which it emitted, and demanding that it should be raised. During the whole of this time, this ventilator was absolutely disconnected from the
sewer.
I
On account of the great differences in level, which obtain in Victoria, it may be well to divide the sundry districts into zones of equal level, by introducing properly-formed traps in the street-sewers. Each zone might be separately vented, thus preventing a great out-pouring at any one group of vents. do not recommend that this be done, until the necessity for so doing has been established by experience. Any attempt to produce a definite current, in some fixed direction up or down, is to be deprecated. It will not succeed, on account of the wind-eddies which prevail in Hongkong. It is moreover undesirable.
79. The construction, renewal, alteration and repair of House-sewers is now supervised by the Sanitary Board, who are provided with a Sanitary Surveyor, for this purpose. The construction is performed, only by certain contractors, licensed by the Board. No unauthorised person is allowed to do any work, in connection with house-sewers. The Architect designs the house-sewers and the plan is sub- mitted to the Sanitary Surveyor, for his approval. If the contractor for the con- struction of the house, is not one of the licensed contractors, he must arrange with one of them, to carry out this part of the work. The house-sewer contractor, finds the pipes and other appliances, obtaining them wherever he pleases. After com- pletion, but before the ground is filled in, the work is inspected and tested for water- tightness, by the Sanitary Surveyor.
80. The pipes and other materials are procured locally, and are, doubtless, the best that are at present available.
I am, however, of opinion that they are not of the pattern and quality that is now considered essential. I see pipes, apparently of Chinese make, that are not fit to be used, for any sanitary purpose, whatsoever. Speaking from memory, neither the Chinese pipes, nor those manufactured by the Aberdeen Company, are as good as they used to be.
81. The use of indifferent pipes and fittings is a serious evil. The Sanitary tions to the Surveyor, in order to get work done at all, has to pass house-sewers, constructed, not as he thinks they ought to be, but in the best way that he can get them done, under the circumstances, and with the available pipes. If crooked or deformed pipes are used, it is impossible to construct a true and accurate sewer. Then house- sewers are indeed tested, after construction, with water under pressure. If, on testing, one or more pipes prove to be leaky, then the only satisfactory plan is to take out the whole length and re-lay it. It is difficult, almost impossible to break out one pipe and replace it, with another so as to make a satisfactory job.
Pipes shoul
and tested
before use.
Tests to be applied to
sewer pipes.
82. It is therefore desirable, in the interest of all concerned, including Owners and Architects, that all sewer-pipes should be tested and inspected, before they are used. The Contractor would then know that he is using materials with which he can make good work, and that will pass the final inspection and test provided that he lays and joints properly. Under this arrangement, much less will be left to the individual judgment of the Inspector. He will not be called upon to decide whether the work is good enough, in his opinion, or as good as can be made with the inaterials available, but whether it is in accordance with the general Specification, a document which should be accessible, both to Architects and to Contractors.
83. Every Sewer-pipe should be tested with an Hydraulic Pressure, of one at- mosphere. Few pipes will actually burst under this pressure, this test is mainly of use for detecting cracks or porosity; of course, occasionally, a very bad pipe will burst. A test may indeed be effected by placing the pipes upright, with their spigots embedded