Sanitary Engineering in Victorian Times written c1870

Thursday, 15 January 2004 08:09 PM GMT

Contributed by: jami brooks

Cisterns and Economy of Water - Ventilation of Pipes

We now proceed to give the detail of various inventions for storing and also for economising the supply of water. In the last century cisterns were almost invariably made of lead, in some cases cast solid of sufficient thickness to be fixed without external casing; the outside was often decorated with panelling in designs, and sometimes with coats of arms. The usual mode, however, was to provide a strong wooden cistern, which was subsequently lined with lead soldered together at the angles, either cast in sheets or rolled in a mill, described in the first case as "cast" and in the latter as "milled" lead; and this latter system is still extensively in use.

Within the present century, however, several other materials have been adopted for the purpose - e.g., cast iron in one piece for small cisterns, and in a number of plates jointed together with flanges and bolts for those of larger dimensions, the joints being rendered water-tight with cement. Examples of this class of construction may be seen in the water-tanks for the supply of engines at most railway stations.

The introduction of slate is,however, the most important feature of modern times in the construction of what may be termed household cisterns, and as it is much cheaper than lead, it has almost entirely superseded its use for all common purposes. The increased facility in obtaining what is called slab slate of late years, renders it possible for all except very large cisterns, to be constructed with the ends, sides, and bottom each consisting of one single piece of slate. These are rabbeted together at the angles, confined in their place if necessary by small iron bolts, and the joints rendered water-tight with red lead. As slate, from the desity of its texture, is scarcely affected by atmospheric changes, when the work is once properly executed, these cisterns are perfectly efficient. They are also free from an objection that applies to lead of all descriptions, and that is, that especially with soft water, when the water remains for any considerable time in contact with the lead, a chemical action takes place by which the water holds a certain quantity of lead in solution; and if this be allowed to proceed to any extent, the result when the water is used for drinking is verey deleterious producing the symptoms which are well recognised as those of lead poisoning.

Another material recently introduced for this purpose is sheet iron, which should always be galvanised to protect it from rust. The sheets are riveted together, and, where the size is so large as to require it, strengthened with iron cross-braces. This material is largely used for ships' tanks, as well as for household cisterns, and most of the large workhouse infirmaries erected recently, and also the large groups of buildings carried out for the Metropolitan Asylums' Board, have been provided with cisterns of this construction.

Where, however, as is often the case in country house, the general storage for the water is below the level of the ground, a brick tank is the usual receptacle. This can be made perfectly water-tight by a lining of cement within, and when the size is unusually large and the depth considerable, an outside coating of asphalte may be employed with advantage.

Having thus describred the materials for the construction of cisterns in ordinary use, we now give details of various contrivances for economising the water-supply.

In districts where the supply is limited, or in houses where the cistern accommodation is comparatively small, it becomes important that the requisite flushing should be done with the minimum quantity of water, and for trhis purpose various inventions have been introduced. The one shown in Fig. 10 is Hooker's pattern, divided into a smaller and larger compartment, with levers and valves, so arranged that the contents of the smaller cistern only are discharged for flushing purposes; the same action that releases the water closing for the time the connection between the two, which is restored when the operation is complete; the main store being thus retained intact, and the smaller portion refilling itself immediately.

Our second illustration (Fig. 11) shows a flushing cistern of somewhat similar construction, but so arranged as to be independent in itself, and to be attached to any ordinary larger cistern already fixed or otherwise, the same object being obtained.

Our third sketch (Fig. 12) shows another adaptation of the same principle, but with a horizontal instead of a vertical division, the whole construction in this case being of cast iron.

In a previous paper we have had occasion to call attention to the difference between "constant" and "intermittent" supply, and our next illustration (Fig. 13) shows a contrivance for the economical supply of water to a closet where there is a constant supply at a considerable pressure, for which purpose only it is adapted. The air-chamber, which is of cast iron, must be connected with the main, and perfectly air-tight. The weight of the head of water compresses the air within the chamber, and fills it with water up to a certain point, the quantity being sufficient for the thorough service of the closet. When the closet is used the connection with the air-chamber is opened, the compressed air regains its original volume, discharging the water forced in by the pressure, the same action severing the connection with the main, which by the return action is again opened, when the air-chamber again charges itself as before, about two minutes being the time required, or even less.

This apparatus, which is called Common's patent high-pressure closet, has been used extensively and successfully in Brighton and other large towns where a constant supply is in operation. In a subsequent paper of this seies we propose going in fuller detail into the various descriptions of closet apparatus, and therefore omit at this point any description of the remaining portion of this sketch, which is only introduced as an illustration of a certain class of methods for economising water-supply.

Regulators, of which Howard's patent is perhaps the best of its class, are another means of attaining the same object. they are attached to the water-service at its junction with the apparatus, and not to the cistern, and consist of a brass valve so arranged that the delivery of the water can be regulated by a screw at pleasure, in accordance with the head or body of water to be dealt with. The rush consequent upon the working of the ordinary closet is thus avoided, sufficient water only being delivered to do the work thoroughly without waste. When the water, however, is charged with any foreign matter, the small aperture in the valve is apt to clog, and thus its efficiency is interfered with. In these cases Underhay's system may be adopted with advantage. Here the supply of water is received into a valve constructed with leather, like a bellows, the same result as before - a gradual discharge - being obtained; the leather, however, is perishable, especially if it be exposed to damp externally.

Having thus briefly described some of the methods in ordinary use, for economy in the use of water-supply in connection with drainage, before going further into the details of valves and closets, which will form the subject of our next paper, we wish to call especial attention to a matter we venture to think not generally understood, and that is the ventilation of pipes.

Lead is still the material generally in use, and will probably continue so to be; but whether of lead or of iron, or of any other material, our remarks will equally apply. One of the most important sanitary requisites in buildings of any kind is good plumbers' work; and there are tqo all-important requirements. The first is, that the styrength of the material shall be sufficient, and the work well executed, as in no trade is perfection of workmanship more absolutely necessary, the least defect revealing its presence by its unpleasant and unhealthy consequences. But the second is equally important, and that is ventilation, as we shall proceed to explain, for the work may be perfectly well executed, and yet if this second requirement be either neglected or misunderstood, unsatisfactory results ensue, the cause of which is often obscure and difficult to trace. The great secret is to provide for the escape of all foul vapours to the outside air by means of the pipes themselves. Ordinary building specifications, as drawn even by the best professional men, are often wanting in explicit detail in this respect. The common wording is, "provide all necessary air pipes," the details being too often left to the discretion of the working man. Every soil-pipe should have a ventilating-pipe from its topmost point, communicating with the external air, of not less than two inches in diameter, and then the pipe itself becomes as it were the flue by which the remainder of the system with which it is connected is ventilated; and in some cases this is so completely carried out where unusual care is required, that a 2inch lead air-pipe is taken from the outgo of the trap and branched into the main air or ventilating pipe of the soil-pipe. We may mention Sandringham House as an instance of the adoption of this precaution. The next point is to prevent any foul air from becoming what is technically called water-bound, i.e., that when flushing takes place, a free escape should be provided for the air displaced, which, unless this is done, bubbles up through the water by which it is supposed to be hermetically confined, with the usual unpleasant results; and sometimes even when the plumbers' work is perfect in itself, a want of attention to this same point of water bound air in the drains will produce the same result. Objections are frequently made to erecting closets in confined situations from fear of the want of general ventilation; but if the above precautions are carefully attended to by an expert, they ought to be absolutely and perfectly free from smell in whatever position they are placed.

The question of ventilation is all important in matters connected with drainage. Miss Nightingale says, "I have met just as strong a stream of sewer air coming up the staircase of a London house asd I ever met with at Scutari, and this sewer air is retained in the bedrooms. No house with an imperfectly trapped pipe communicating with the sewer from the sink, can ever be healthy, and may at any time spread a fever among the inmates of a palace." The memorable illness of the Prince of Wales gave onle too striking confirmation to this well founded observation. In our present paper we have given, as far as our limits have allowed, some guidance as to the general principles to be adopted for the complete avoidance of all danger as far as internal construction is concerned; and as we proceed with the subject, we hope in some subsequent paper to show how by the proper trapping of drains external to the house, with ventilation always kept in view, the evils which we fear are only too common may be effectually guarded against, the noxious gases evolved from sewerage harmlessly discharged into the external air, and typhoid fever, with its cognate disorders effectually kept at bay.



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