CHAPTER VII THE BuILDING—ITs WATER SUPPLY (Part 2)

fixed flush with the face of the plastering. Wood plugs could be used but the wood fillet makes a better job. If a secure fixing can be obtained without the use of wooden plugs or fillets, the use of them should be avoided. Plugs often become loose by reason of shrinkage, unless they are made of very well-seasoned wood. The clips can also be of brass if preferred. Another method is to attach “tacks” of sheet-lead to the side of the pipe, by means of solder. Fig. 165 shows an elevation and Fig. 166 a sectional plan of such a method of fixing, the tacks being marked T. A wood ground is shown, fixed to plugs driven into the wall, and the tacks, or lugs as they are sometimes called, are screwed to them. The sketches show a double tack, but single tacks are often used for small pipes. Tacks or clips, whichever may be used, should be about a yard apart. ielid Pipes under Floors or in Lofts. As lead pipes have so little rigidity in themselves, they need some support when laid under floors or across the rafters in unboarded lofts or similar places. If they run parallel to the joists or rafters, they should rest on a batten or ledge, fixed to the timbers at a slight slope to permit the pipes to be drained if necessary. If they run across the joists, these should be cut away or drilled to make way for the pipe, with supports from joist to joist under the pipe to prevent sag. In the loft space, a length of floorboard or batten can be nailed across the joists to support the pipe. 208 THE BUILDING—ITS WATER SUPPLY i. Ms ‘gl KH K THE BUILDING—ITS WATER SUPPLY 209 Jointing Iron Water Pipes. The best method of jointing iron pipes is to have a screw thread on each end of each pipe and join the two pipes together by means of a loose iron collar having a thread internally; the threaded ends of pipes and inside of collar should be smeared with red lead, and a few strands of spun yarn, smeared with the same substance, should be wound round the threaded ends when the joint is made. In the case of joints under- ground, the exposed threads, after the joint is completed, should be painted with red lead for protection from rust. Joints for Lead Service Pipes. Lead and lead alloy pipes for water should always be jointed by means of the plumber’s wiped- solder joint. Fig. 167 shows a part section and an elevation of such a joint. The abutting ends are fitted together as shown, and a length of a few inches on each pipe is painted with a mixture of whiting, lampblack and thin glue, termed “soil”; the ends are then scraped lightly with a tool called a shaving hook. The remaining soil keeps the flux from flowing and gives a clean end to the joint. The solder is then poured on the joint and wiped with a special cloth to the shape shown, a part of the “soil” being left exposed to give a finish to the joint. Usually the opened end of the one pipe is rasped down for neatness of job. Amalgaline Jointing. A method of jointing lead pipes in an entirely different way is that known as amalgaline jointing. There is no bulbous projection as with the wiped joint, the pipe being, externally, continuous in appearance, as shown by the section in Fig. 168. The two adjacent ends are fitted together, as in the sketch, by means of special tools. The abutting surfaces are then cleaned, and a strip of amalgaline wound round the end of the pipe marked A. Amalgaline is tinfoil coated with a mixture of stearine and vaseline and is used in the form of a ribbon 0-002 inch in thickness. The abutting ends of the pipe are kept close together while heat is applied by a blow pipe, the ribbon melting and the two pipe ends being fused together. Special fittings are needed for T junctions, as shown in Fig. 169, and special sockets are obtainable, if desired, for a joint on a straight length as in Fig. 168. In the latter case, the abutting ends of the pipes would both be shaped as at A in the figure, to fit the opposite ends of the socket. The method is simple, strong, neat in appearance and economical; the fact of its being simply and quickly made has prevented it becoming a favourite with the plumber and the joint has not roved a commercial proposition. ib Another method of jointing lead pipes in an expeditious manner, such as for temporary work, is by means of special sockets, such 210 THE BUILDING—ITS WATER SUPPLY as shown in section and part elevation by Fig. 170. The adjacent ends are bossed out as shown and separated by a ring of triangular section, marked R; two other rings, one plain and one threaded, are placed outside, and the whole tightened up by a nut as shown. This joint, first introduced many years ago, did not have much sale. Since the introduction of compression joints for copper tubes, it has been put on the market again. Jointing Drawn Copper Tubes. If copper tubes are used, they may be jointed by capillary soldered joints or by welding, or by the compression joint, an example of which is shown in Fig. 171, which is similar in principle to the joint of Fig. 170. The ends of the tubes are bossed out and the ring, R, put in between. The collars, C, one of which has an external screw thread, are placed over the tubes and they are drawn together by turning the union nut, U. This presses the ends of the tube tightly against the internal ring, R. Service Tanks. The main pipe entering the building from the outside is termed the rising main. It passes up to the cistern, or cisterns, which may be either open or closed, and of various materials, The usual form is open. The commonest form is that built up of riveted or welded steel sheets, the whole being galvanised after construction. The tops have turnover flanges to stiffen them, with stiffening plates at the corners. The inlet and outlet holes should be drilled before galvanising. These are relatively light, cheap and durable, unless the water is very acid, when corrosion soon takes place. Gal- vanised steel cisterns have been standardised in B.S.S. 417. Galvanised cisterns should not be used if the pipes are of copper, as electrolytic action is likely to occur between the copper and the zine coating of the cistern if the water contains free carbon dioxide. Generally it is better that pipes, cylinder and tank should be in like metal. Very large cisterns are sometimes built up of wrought-iron plates or of cast-iron sections, protected against corrosion. The “Angus Smith’? Process. In the case of cisterns built of cast-iron sections, the sections are usually flanged and bolted together, a tight joint being made by planing the abutting flanges and placing a packing of oakum between. The best protection against corrosion is given by what is known as the Angus Smith process. Immediately after casting, the parts are heated to about 600° F’, and dipped into a heated solution (about 800° F.) consisting approximately of four parts of bitumen, three parts of prepared oil and one part of paranaphthaline. THE BUILDING—ITS WATER SUPPLY 211 Bower-Barffing. Another process is “ Barfling”’, which consists of forming a coating of black magnetic oxide over the whole surface. Wooden cisterns lined with lead, zine, or copper were once largely used, but they have been almost completely superseded by the self-supporting type of galvanised iron or copper. They can be readily made of any shape to suit awkward positions, but have practically no other advantages. Lead and zine are both quite unsuitable for the storage of soft water. Slate Cisterns.. Slate cisterns have no injurious effect on water, but are very heavy. They are constructed of slabs fitted together with grooved joints and strengthened by means of rods or bolts passing from side to side. The joints are made watertight by a paste made of red and white lead, but care should be taken that the water cannot come in contact with the jointing material. This can be prevented by brushing over the joints with bitumen. Glazed stoneware cisterns are very heavy, but, like slate, do not prejudicially affect the water. They are easily cleaned, owing to the glazed surface, but cannot be obtained of large size. Protection of Drinking Water Tanks. All cisterns of the fore- going type should be covered with a tightly fitting wooden cover. All cisterns should be placed in well-lighted, ventilated, and easily accessible positions, so that they may be readily inspected, re- paired or cleansed. Tanks in Lofts. An unprotected loft is not an ideal place for a service water tank, but if it must be used to conserve space, the pipes should be kept away from the eaves and should be lagged with felt strip or other insulating material to safeguard them in frosty weather. The best way to “lag” the tank is to construct a casing of wood or asbestos cement sheets round it, leaving a 2-inch space which can be filled in with asbestos fibre, granulated cork or some other insulating material, taking care to see that the rising main where it rises from the ceiling joists to enter the tank at the ball valve gets equally satisfactory protection. A useful way to protect the top of the tank is to use a metal drip tray such as is sometimes used in a garage under a car engine, This is generally about 2 inches deep and can be filled with the same type of insulation as that used round the tank and the size can allow a 2 inch margin so that it reaches the tank casing. The wood cover can then be omitted. Other precautions which should be taken against risk of damage by frost are: (a) The service pipe leading to the house should be kept at a safe depth. The requirement varies with different water under- 212 THE BUILDING—ITS WATER SUPPLY takings’ regulations, but to be safe, 2 feet 6 inches should be the minimum until well under the building. (b) The rising main should be carried up in a pipe-duct inside the building or at least against an inside wall. If fixed against an outside wall, the pipe should be well lagged—behind the pipe as well as front and sides. (c) Careful lagging or other protection of all pipes in roof space or other exposed places. (d) Casing of cisterns as just described. Ball Valves. The various inlets and outlets of cisterns next call for notice. The inlet to the ordinary open cistern takes the form of a ball valve, or automatic “tap”. There are a great many varieties, a few of which will be described and illustrated. Ball valves are made for low, medium and high pressures. These are usually defined as follows: Approximate Type Water Head | Ib. per sq. inch LOW oss as Under 90 | Medium. 90-230 | High. . weo-400 | 100 to 200 Under 40 40 to 100 The appropriate B.S.S. are Nos. 1019 and 1212. The Croydon Valve. One of the oldest forms is that known as the “Croydon”. The low pressure form of this valve is shown in Fig. 172, the lever being broken off at A to permit of the more complicated part of the ball valve being shown to a larger scale. The course of the incoming water is shown by arrowheads. A plug B is connected to the lever at C, and when the cistern is full the plug is held up tightly to prevent the admission of more water. The upper part of the plug B is shown in the elevation by dotted lines and in cross-section by the small sketch at the side. The cross-section of the plug is such that, when the ball falls, as it will do when water is drawn from the cistern, water is able to pass in from the rising main. This type of ball valve is still in extensive use, but it is only suitable for low pressures, is noisy, and is primi- tive in principle. A “Croydon” high-pressure valve is shown in Figs. 174 and 175. In this case the outlet for the water, O, is smaller, a circular plug or piston being held up against it. The plug has a rubber washer, shown in black. From the section it would look as though there THE BUILDING—ITS WATER SUPPLY 213 *3 es: ei %. ‘ 44 f 7 7 214 THE BUILDING—ITS WATER SUPPLY was no way out for the water, but the section of the casing around the valve is in the form shown in Fig. 175. Like the low-pressure valve of this type, the high-pressure one is noisy, the water entering in two disjointed streams and, unlike other forms of ball valve, no method of silencing can be adopted. The Portsmouth Valve. Another well-known form is the “ Ports- mouth” ball valve. The high-pressure valve of this type is shown in Fig. 176, the plug being horizontal instead of vertical as in the previous example. It will be seen that the falling of the lever, as the copper ball at its end sinks, opens the waterway, O, and the water passes vertically downwards through a short tube, T. The screw cap at the end is for the purpose of obtaining access to the plug when it is necessary to fit a new washer. A recent development in ball valves is an interchangeable diaphragm, so that a corroded one can be renewed or “high” changed to “low”. This form of ball valve, or indeed any with a tube outlet, can be rendered silent in action by attaching a lead or composition pipe to the outlet tube, thus lowering the point of discharge to an inch or so above the bottom of the cistern. It will be seen that such a pipe could not be attached to a “Croydon” valve. The Equilibrium Valve. The best kind of ball valve is that known as the equilibrium variety. The simplest form of such a valve is that shown in Fig. 177. The waterway is closed by a vertical piston, P, which holds up a leather or rubber washer against the outlet. At the upper end of the piston is another washer, in the form of what is known as a “cup” leather, so called from its shape, as shown in black in the section. In the two varieties previously described, the water is always tending to force the valve open, but in this example the valve is kept in equilibrium by reason of the fact that the water pressure is acting equally on the lower and upper washers. At the same time, the fall of the lever readily opens it and on rising closes it. Another example of the same type is shown in Fig. 178. It will be seen that the principle is the same though the construction is different. There is not the vibration and consequent wear on the valve in the equilibrium form that there is in others. This type is suited to both high and low pressures. Another form of equilibrium valve has a small-bore waterway leading to a water chamber beyond the plug so that water pressure is maintained on both sides while the valve is closed. Another form of high-pressure ball valve is that involving the THE BUILDING—ITS WATER SUPPLY 215 use of compound levers, arranged so that a very slight upward pressure on the copper ball exerts a considerable thrust on the valve. Fig. 179 shows a well-known variety of this type. It will be seen that a small force acting upwards at the end of the lever, L, would cause a much greater force to be transmitted to the end of the short lever, L. Ball valves require occasional adjustment, due to the straining of the lever carrying the ball. This lever is of small section and is usually bent by the plumber in order to put matters right. To guard against the risk of breaking the lever by this practice, an ingenious arrangement, shown in Fig. 180, has been introduced. The lever is in two pieces, A and B, and the necessity of bending the lever is overcome by the provision of a small adjustable screw, S. Having considered the forms of inlet to cisterns, let us next con- sider the outlets and the methods of connecting them. The out- lets serving fittings should be connected to the side of the cistern, about a couple of inches above the bottom, so as to prevent any sediment that may accumulate from passing to the fittings. An overflow pipe should be provided in all cases, fixed just below the level of the inlet valve and discharging through an external wall in a fairly prominent position so as to act as a warning pipe, since this pipe will only come into use if there is anything wrong with the ball valve. In large cisterns a cleaning-out pipe should be provided, having its mouth flush with the floor of the cistern, controlled by a stop valve, and discharging through an outside wall and over a rainwater head. The mouth of this pipe can be closed by a plug attached to a chain fastened near the top of the cistern, or a closed vertical pipe ean be attached to the plug to enable it to be lifted out. Some- times the case is dealt with by putting a trumpet-mouthed vertical overflow pipe, the lower end of which fits into the mouth of the cleaning-out pipe and so forms a plug. This is not a good practice, as it does away with