CHAPTER VIII. WATER SUPPLY. (Part 5)

We must now pass on to consider the question of water storage, which is a very important one, and deeply concerns the plumber. There can be no question in town water supply between the merits of constant supply and the demerits and dangers of intermittent supply; the great evil of the latter being that, when water is shut off, foul air, foul germs, and foul Fi(i. 368. — Cast-iron storage tank. sewage even, may be drawn into the mains through defec- tive pipes and open taps. The waste of water from leakages and defects has been proved to be greatly in excess of that occurring under a constant supply. Delay in getting water turned on if a fire occurs is a serious source of danger. The water cannot be used for motive power. The number of turncocks employed must be in excess. Cisterns must be provided to retain water, exposed often in unwholesome positions, and generally they are found on examination to contain filth. The very poor collect and keep the water 414 DOMESTIC SANITARY DRAINAGE AND PLUMBING. in unsuitable and dirty vessels in overcrowded rooms, where it becomes dangerous rapidly. In the constant system in towns, cisterns and tanks are generally forbidden, except for boiler supply; but it will serve our purpose to include all methods of supply in our consideration of the question of storage, for even under the constant system it is well to have a reserve of water, always provided that it can l^ perfectly arranged, to maintain the water so stored pure and wholesome. We must now assume that we have arranged an abundant and pure supply of water, and have brought it by the best means to the desired level in the main tank. The position and surroundings of the tank are of great importance, both for the reputation of the plumber and the health of the household. A small, well-lighted, well- ventilated room should be reserved as a tank-room. It should 1)0 secured from frost, fitted with a locked, air- tight door, to exclude the air of the house from the room ; and it should be kept for the exclusive safe custody of the tank. Too often it is used as a housemaid's lumber and dust room. The floor, walls, and ceiling should be made impervious to exclude doubtful air, and be glazed so €is not to hold dust. The floor should be lined with sheet lead, five or six pounds to the foot, turned up at sides, and with a 2-inch or 3-inch waste-pipe, ending in open air, with a copper flap- valve on to exclude air. The tank should be raised on iron girders, eighteen inches over the floor, to allow easy access to the under side for repair or inspection and cleaning. The tank should have an overflow-pipe large enough to take any water from accidental leaks^e of ball-cocks, if such WATER SUPPLY. 415 be used, or if supply-pipe be left open from a pumping engine; the overflow should be carried to a safe point to fill a flushing tank, or to serve as a warning-pipe. A proper arrangement for emptying tank easily for periodic cleaning should always be provided, taken from the lowest point in bottom of the tank to a safe point of discharge. It is very wrong for water companies to prevent this as some do. Large stand-pipe overflows and wastes, three inches or four inches in diameter, from high-level cisterns are not desirable, for the rush of water and consequent strain on fittings is generally too great, and may collapse the pipes. The choice of the material of this tank should be decided by the quality of the water. If the water be of that kind which does not attack lead, the store tank may best be made of seasoned timber, planed smooth and dovetailed at corners, and lined with 7-lb. or 8-lb. sheet lead, or the sheet lead alloyed with three per cent, of tin. If the water be liable to attack lead, then a cast-iron tank not galvanised will be the safest and best. Some authorities say that galvanised-iron tanks for storage should be avoided. The Bower-Barff process of preserving iron has not borne the test in trials made by the author with welded wrought- iron range boilers in contact with Dublin Vartry waters, but it might prove more successful if applied to cast-iron tanks, and, if so, would be very useful for store tanks. The process consists of heating the iron in a furnace to red heat, and admitting a jet of superheated high-pressure steam to play upon its surface, when a black magnetic oxide of iron is formed, which is said to be proof against further oxidation. The coating is very hard and brittle, and, if damaged, will of course have no efitect. It hardens gun-barrel so much that it 416 DOMESTIC SANITARY DRAINAGE AND PLUMBING. cannot have screw-thread tapped on it until annealed, and the annealing injures the Barffing process. Store tanks require monthly cleansing, whatever the material may be. The tanks are sometimes allowed to get into a disgusting and dangerous condition, because some waterworks authorities will not permit pipes to be taken from the bottom of tanks to empty them easily for cleansing purposes. Overflows and w«istes, when used, require great care in discharging their ends at a point where no foul or doubtful air can get back to contaminate the water in the store tank. The size of the store tank should be very carefully con- sidered and settled according to local circumstances ; no fixed rule can be given. In suburban and country mansions the storage must be greater than in towns, and it can generally be arranged more safely also. Tanks had better be omitted altogether unless they can be rendered safe. A downward distributing pipe is to be led from the tank direct to basement, and all branches to baths and auxiliary cisterns are to be taken from this pipe. Two or more main distributing pipes will be desirable in large mansions. It is a good plan, where permitted, to affix a hose-screwed cock on this pipe at basement, and to provide hose and hand- pipe for cleaning windows and washing out corners in the basement passages and yards. Stop-cocks may with advantage be placed on all draw-oflF pipes close to the store tank, to be shut off when repairs are needed on pipes or valves. CHAPTEE IX. HOT-WATER SUPPLY. The hot-water supply, storage, and distribution require careful attention. An imperfectly arranged or constructed system is an endless source of trouble and expense. Large quantities of very hot water are supplied in hotels and large mansions by means of a steam-boiler and closed iron or copper tanks, with coils of steam-pipes placed inside, the steam-coils being connected with the steam-boiler. The water heats rapidly, and can be drawn direct from the tank, or caused to circulate round the building to any positions where hot water is reqiiired. This plan is sound and economical where the steam-boiler is required for other purposes, as heating, cooking, or pump- ing water, and as a proper attendant should be appointed for the care of steam-boiler and engine, the amount of work to be done by it should be sufficient to warrant the expense. Otherwise the hot water can be more economically supplied from an ordinary independent boiler on a metal base, or set in brickwork, the size and form being arranged after due con- sideration of the fuel to be used, the character of the water, and the quantity of hot water required. Modem dwellings of moderate size will usually have a boot-shaped, welded, or riveted wrought-iron or copper boiler behind the kitchen range. These boilers should be fitted with two manholes for 2 s; 417 418 DOMESTIC SANITARY DRAINAGE AND PLUMBING. cleaning, one on the front above the skirting of the hot-plate of the range, well in view, and easily unscrewed, and the other on the top of the toe of the boot under the hot-plate, the hot-plate immediately over the boot being made to lie loose, without screws, and lift off, for easy access to the man- hole underneath, as the greatest amount of deposit takes place in the toe, which is actually in the blaze of the fire. It is usually in the toe that boilers give way and leak. The general cause of failure is that a coating forms inside, and is not properly removed. lime waters sometimes are so strong that boilers need thorough clearing once in three months. Every range boiler needs cleaning at least once a year. When boilers make a sharp, cracking noise, like a mallet struck quickly on iron, the cause will generally be traced to choking up of the flow or return pipes with deposit, and the noise gives wholesome warning of impending danger. When they make a thump, thump, thumping noise at odd times, which ceases when hot water is drawn off and replaced by cold, the cause is probably air in the boiler, from some defect in construction, or air in the pipes, from some defect in laying them. Every high-pressure circulating boiler should be made so that no bubble of air can remain in it. The boot-boiler instep or top of toe should always slope well up towards the leg, and have the toe which lies in the fire well rounded. All parts should be rounded and comers avoided in boilers, especially where the fire plays on them. If the instep be flat, some inequality of inner surface or some change of level may afford a resting-place for air, which not only keeps water from contact with hot-plate of boiler, so that it bums out soon, but causes annoyance by noise and bubbling. The upper top of the boiler, though not actually in the fire, should also be flat and smooth, and care should be taken in setting to level it, so that every bubble of air shall flow easily HOT-WATER SUPPLY. 419 away up the flow-pipe, asnd to this end the flow-pipe must not project in the slightest degree below the inner surface of the top. To ensure no mistake on this point, it is a safe plan to screw down a flange socket on the top of boiler, screwed inside, to take the outflow pipe, and the hole in boiler to be drilled slightly smaller than this socket, so that the pipe cannot be screwed down through the boiler even by a careless workman. For the same reason the outflow should be taken ofif the Fio. 359. — Common defects in boiler arrangement top of the boiler, not off the side or back, as it is almost impossible otherwise to avoid leaving a space for air. The diagram will explain this. The return pipe is generally more conveniently placed if led in through top of boiler at opposite end, and an inner prolonging pipe screwed on inside to carry return column of water down within six inches of bottom of boiler. The outlet and inlet pipes should be screwed in as wide apart as possible, to allow room for damper of flue between them. For rain and soft waters boilers should have copper 420 DOMESTIC SANITARY DRAINAGE AND PLUMBING. pipes from boilers carried beyond reach of the flue beat, and here brass couplings hard-soldered to the copper at one side, and soft-soldered to lead pipes on upper side, may connect the circulating pipes, which are usually of lead, with the boiler. In some districts iron or tinned copper pipes are used for hot supply. Every boiler should have a cleaning or emptying pipe taken from its lowest points, but arranged with stop-cock, having a screwed cap on its end, so as to prevent water being drawn off by servants, unless for cleaning the boiler when fire is out and boiler cold. No water for house use should be drawn direct from boiler. An intermediate hot- water cistern, the cylinder being the best form for resisting pressure, and of a capacity propor- tioned to power of heating of the boiler and the wants of the household, may be fixed in a suitable position above the boiler. Copper cylinders are too often fixed of such light material that they collapse when cold water is turned on suddenly. Galvanised iron cylinders should be made with tops bolted on, otherwise the galvanising inside may be imperfect and the cylinder quickly fail from rust. There are many elaborate systems of hot-water circula- tion, some complicated with valves, some with hot-water cisterns on same level as cold-water cisterns; but the simplest and safest system is that here described (we shall omit reference to other plans). If a linen closet be at hand on the basement, or not higher than the first floor, that will be the most useful place for the hot cylinder; winter and summer it wiU yield warmth to keep the linen dry and aired ready for use. If the kitchen be lofty and airy, so that the heat from the cylinder in summer will not be too great, that position will suit well, because the scullery and kitchen hot-supply pipe must be always taken from the top of cylinder, and this HOT-WATER SUPPLY. 421 pipe will be thus shortened ; but the heating powers of the cylinder, you observe, are here wasted always, and may be troublesome in summer. If there be a passage or staircase near at hand, perhaps the hot cylinder may be placed so as to utilise the heat in winter, casing it in during summer and conveying the heat away. Hot cisterns are often hid away under roofs, where one has to scramble in darkness on hands and knees to examine and repair them, and where they are likely to remain with- out cleaning from year to year, till they wear out or leak. The repairs of cisterns and pipes in such positions occasionally result in the whole house being flooded or burned down. A case occurred where a plumber, from sheer laziness, when leaving off work, sent his lad to remove the tools from such a position, and the lad, following the example of his master's carelessness, set fire to the roof and to the house. The hot cylinder should be placed above the boiler, in a position admitting of an even gradient for the circulating pipes. The best range of distance will be found between ten and thirty feet from boiler, not giving too long a pipe for circulation and its consequent friction. Hot cisterns should be tested to bear double the pressure due to the head of water from the cold-supply cistern. If 20-feet head, the pressure due is nine pounds per square inch ; therefore the hot system should be tested to carry eighteen pounds per square inch at least, and for very strong work twenty-seven pounds per square inch. Every closed hot cistern should have a large cleaning door, or manhole, securely screwed down. The pipes should be attached into strong screwed bosses with flanges affixed to the cistern before it is galvanised, so as to galvanise the bosses also. There are generally five bosses required — one on top for steam escape, expansion, and draw-off; two at the lower end of the side for circulating 422 DOMESTIC SANITARY DRAINAGE AND PLUMBING. pipes ; one at the lower end of the opposite side for the cold supply ; emd one at the upper end of the side for basement draw-off pipe. Tinned copper cylinders are superior to galvanised-iron cylinders. For ordinary houses the sizes of pipes are best arranged — 1-inch circulating pipes, 1-inch draw-off and expansion pipe, f-inch draw-off pipe for basement, and IJ-inch cold- supply pipe. To suit various requirements these dimensions may be enlarged or reduced, but the proportions may safely be followed. Fia. 860. — Three circalatiou systems. There are many methods in use for bringing cold supply into the system — direct into the boiler, or branched into the return circulating pipe, or, as above indicated, into the inter- mediate hot cylinder. Cold water entering a hot boiler in contact with a blazing fire must injure the boiler by causing rapid contraction ; by entering the return pipe with a sol- dered joint the joint constantly fails, owing to expansion and contraction of the metal. But when the cold supply is brought into the bottom of hot cylinder, opposite to the return pipe, so that cold water may flow across, mixing slightly with the bottom layer of hot water, so as to raise HOT-WATER SUPPLY. 423 the temperature before it enters the hot boiler, the cold water does not thus mix with the upper water of the cylinder, which can be drawn oflf at its hottest, when required. The diagram shows three plans. All branch supplies of hot water may be taken from the expansion pipe, but some- times a special draw-off pipe for basement hot water is provided with advantage direct from top of cylinder. It is frequently desirable to induce a secondary system of hot-water circulation past the various hot-water draw-off taps over baths, etc., when such fittings are far from the cylinder, in order to secure an immediate supply of hot water at these distant points, and this is effected by carrying a ^-inch return pipe from the ends of these hot branches back into the cylinder, or into the return circulating pipe between cylinder and boiler. The same arrangement can be made to act as means of preventing the cold-water pipes freezing up in winter, by carrying the hot pipes near the cold ones, though not in contact. Care should always be observed, in laying pipes hot and cold together, to separate them so that they may not both become hot by contiguity, or cause condensation of water outside on the cold pipes. In fitting hot-water supply pipes and cisterns there is room for the exercise of thought and skill Very many badly devised and ill-constructed systems may