Page:The Building News and Engineering Journal, Volume 22, 1872.djvu/116

 100 THE BUILDING NEWS. ‘Fer. 2, 1872. pe LOUTH NEW HOSPITAL AND DISPENSARY COMPETITION. Srr,—I beg to send you a report (cut from last week’s Lincoln Gazette) of a meeting of subscribers to consider plans sent in competition for a new hos- pital and dispensary (under motto), in which it appears one of the competitors (a member of the council of the Royal Institute of British Architects) was present, criticising the designs, and pointing out the advantages of his own over the others. I think such conduct is quite unprecedented.—I am, &e., OccHIrEer. [The report will be found condensed in our notices of Competition.—Ip. | HOT WATER AND FIRES. Srr,—Many steam boilers are actually cased with wood, and not one of such casings has ever caught fire. Consequently the notion that hot-water pipes could set timber alight is absurd, and the sooner insurance offices come to their senses the better.—I am, &e. J. P. Seppon, 12, Park-street, Westminster, January 26th, 1872. PLUMBING. Srr,—At page 78 “ Clerk of Works” observes “it is evident from ‘ Plumber’s’ last sketches that he does not understand the metal valves mentioned by ‘G. H. G.’” Now as it appears to me there is no difficulty in understanding what is meant by the words used by ‘'G. H. G.” at page 478, Dec. 22nd, yiz., ““ Waste-pipes which should have metal valves at their inlets to soil-pipes ;” and although “ Clerk of Works” “cannot see the great objection ‘ Plumber’ raises to these valves,” yet that does not preclude the existence of the objection. I admit the ability dis- played in ‘ G. H. G.’s” article, but I object to these valves, because they are superfluous, and do not ad- vantage the working of the pipes so much as ventila- tion. Besides, the grease, &c., which so often comes down waste-pipes in the dirty water would soon render these valves both useless and a nuisance, and the upshot would be that after much needless ex- pense they would have to be taken out as an obstruc- tion. Wherever the system of allowing waste-pipes to ; enter soil-pipes is in vogue, the style of carrying out the work sketched at page 23, January 5th, renders such proposed valves unnecessary. I am not prepared to knock down the pan-closet altogether, because if it gets proper usage it answers the purpose very well, and in hundreds of houses for which we work it does well. So long as the copper pan which keeps the water up into basin has no holes in it it works well, but when said pan gets holed then it either works bad or else gets choked up unless repaired. This copper pan would last many years, if parties using water-closet would only lift handle and run the water each time.—I am, &c., PLUMBER. vi PLUMBING AND THE SEWAGE QUESTION. Sir,—In thinking over this matter the following are some of the ideas which suggested themselves to my mind :— At present the same drain serves as the common conduit for water-closets, baths, wash-basins, pantry and kitchen sinks, &e.; while soil-pipes have both waste and rain-water pipes branching into them. As a consequence, therefore, the soil from water- closets gets mixed up with an unlimited quantity of waste and rain-water, and the whole compound is carried down in the most promiscuous manner into our rivers, &ec., polluting them to a very high, and now in many cases, unbearable degree. In order to obyiate this and economise the soil instead of wasting it, it might bea step in the right direction if it were to become the practice to have a separate drain for both the soil and waste-pipes—not allowing any waste or rain-water to enter soil-pipe at all. The following sketch will help to show what I mean :— A and B are the syphon traps of two water- closets, branching into the same soil-pipe C, which is ventilayed by the pipe D. This soil-pipe runs into the drain-pipe E, which carries soil along and into the pit-cesspool F. This pit-cesspool, it is under- stood, must be well built of properly-squared and fitted stones, all jointed with cement, and may be also puddled at back with clay. The stones ought also to be polished smooth on the side presented to pit. Good bricks may also serve if well and closely built with cement. No use of lime for rats to bore holes through and so spoil the whole work, The depth of pit, below entrance of drain-pipe E 45 should be several feet, more or less according to circumstances and the work the pit has to do; all the better, however, to have it roomy. ‘This pit is entered at top, which has a close-fitting cast-iron door, on hinges say, by which the pit may be entered, cleaned out, and soil carted away at necessary intervals. This pit-cesspool may also be ventilated by the pipe G, which may be carried up to roof of house. These ventilating pipes should not be put into the fire-flue of a house nor too near their openings, in case when fire is off the flue should conduct foul air down chimney into house. When the pit I is cleaned out it is left’empty, only the parties clearing it out should throw ina quantity of some deodorising sub- stance before leaving. The drain-pipe E, which enters pit, isabout three or four inches higher than thesyphon- trap H, which leads out of it. The soil and water from water-closet comes down drain C and falls into pi F, gradually filling it up, when the soil is in- tended to be retained in pit and the surplus water to run off through syphon-irap, H, to common sewer. In order, however, that soil floating along on top of water may not get into syphon-trap H with the water, a guard must be placed before the mouth of H, as shown at I, so that while water gets over or through it, soil may not; and if this guard could be so constructed as to act as a filter, so much the better. The syphon-trap, H, is put where it is because, if put at side of drain-pipe, E, it would not work; and if the work be properly done, the trap, H, keeps back all smells and rats from common sewer. Should it be feared any rats are in drain, E, light a fire in pit, F, and smoke them out. UY In the above plan it is understood that only the water-closets are connected with this pit, all the baths, sinks, ‘wash-basins, &c., having a drain for themselves, which drain, if so judged, may have also a pit, or if not a syphon-trap must be put on at any rate. The waste-pipe drain may join soil-pipe drain at J. By the above or some other plan it appears to me that this sewage problem ought to be easily solved ; in fact, it is a disgrace to us all—architects, plumbers, and masons alike—if it is not fairly solved whenever the public and those in official situations really make up their minds and desire that it should be.—I am, &c., January 29, 1872. PLUMBER. HOUSE DRAINAGE. Srr,—Herewith I enclose sketch of an iron box or junction, which I proposed fixing to syphon bend at A, provision being made for receiving pipe at b, and also for receiving ventilating shaft, as suggested in your able article of Dee. 15, at C. At dis a small VENTILATING SHAFT self-acting door, which, I believe, in conjunction with the ventilating shaft, will entirely prevent any foul air passing through the syphon bend into the house. As to making the connection with the glazed pipes, I leave that to the more experienced.—lI am, &e., J. Cross. CONCRETE AND MORTAR.—III. Srm,—A_ small thing I neglected to notice in speaking of small-grained sands for mortar—that is, that when too little lime is used, which is generally the case, the mortar, if mortar it can be called, is left porous; rain water, containing carbonic acid, filters through it, dissolves the little lime there is in it, and carries it outside shortly, hardening the out- side coat of mortar, but leaving the inside in time nothing but sand. The outside crust drops off soon, and of course nothing but sand remains. This is especially the case if a little earthy matter be in the sand, and this is the way the lime ots, More lime would have prevented it, though very small-grained sand ought to be avoided unless necessity compels. The same may be said of any sand containing dirty absorbent materials, ORs The reason why ground lime is to be preferred is that for rich limes little more water is required to mix it than is absolutely necessary for the slaking and crystallisation. whose chemical equivalent is 28, to slake requires an equivalent of water 9; for water lost in slaking by steaming, say 2; the second hydration, or water for crystallisation, will require at least another equiva- lent of water, 9; so that 28 by weight of lime absolutely requires for setting 20 of water. water, well managed, will lay in the concrete, or nearly so. water always join ultimately in chemical equivalents, that is, if 28 (one equivalent) be joined chemically with water, the water must be in the proportion of 9 (one equivalent of water) or some multiple of 9, and it is to be specially understood the difference Speaking of rich limes This It is to be recollected that lime and between absorption and chemical combination. The chemical combination of a second particle of water is what gives the mortar its firmness; for carbonic acid may be left’out of the question altogether, as scarcely any is taken up. This may soon be proved by getting mortar from the inside of very old walls, powdering it, pouring dilute acid over it, and stirring a little, when scarcely a bubble of carbonic acid will rise. Try the same with a small quantity of chalk and see the difference. I have seen tried and have tried several old mortars, among others from 8. Radegund’s Abbey, near Dover, and such was always the result, scarcely a sign of carbonic acid. Hydrochloric acid is best for the experiment. Plaster of Paris, which is a nearly anhydrous sulphate of lime, will illustrate the difference between chemical combination of water and its absorption. The plaster, mixed with water, soon sets by combining with water, returning to the original state—chemi- cally—of gypsum, in fact chemically combines one equivalent of sulphate to two of water, forming hydrated sulphate. On the other hand, if a piece of dry-set plaster be put in water, the water fills the pores of plaster, that is, is absorbed. Such is the action on lime, but of course slowly; the water not wanted for hydration must be dried somehow. This absorption of water ruins many buildings. I write this last for the sake of the young, te whom my advice is, learn chemistry. Another advantage in using ground lime is that in the slaking a considerable heat is produced, which is a long time in cooling down. ‘This heat assists, or I may say almost forces on the second, or crys- talline hydration, thus consolidating the lime speedily. Such is the conclusion I came to from my, perhaps, blundering experiments. Having now arrived at the mixing stage, I shalk give my ideas how it ought to be done, and wilk show, especially for the benefit of some sceptical young friends, how the interstices may be filled as full as the Kirkby Stephen conglomerate. Mixing boxes, of which there ought to be two to each set of men, one for mixing while the other is being emptied, ought to be so large as to allow three men to work at the mixing, &c., and pretty nearly water-tight, having ledges fixed on three sides, but movable on the fourth, for convenience of removing the concrete. I shall suppose that we use the Thames gravel and sand, the proportions of which I have some idea of. Larger gravel, 4; very small, 2, or thereabouts ; 1 of sand, 1 of ground lime are the proportions nearly I found best; though I am one of those who do not think gravel and shingle are the best materials for concrete, for one reason, among others, that the water-worn surfaces are too smooth for the lime or cement adhering. All the larger pieces should be picked out, and if thought well of, packed in as the concrete is being placed in situ. The materials being placed on a board should be turned over and over till thoroughly mixed, and be left for watering, not in a heap, but flat, so as to receive and retain water, which ought not to be thrown on in bucketfuls, but added gently while they are being mixed. The water can thus be regu- lated just to whatis wanted. The consistency of thick cream (not London cream, if you please) is about what I have found best. To mix, rakes would be found useful, the spade being kept turning over, and keeping all right for rake’s working. After a thorough work with rakes I would have all chaffed* or wrought over with spade, like chopped-up mortar, as the concrete is put into what it is to be taken away with. I should prefer its being carried away in buckets, but if wheeled on the level barrows may do. On no account should it be thrown into its place, or tipped from a height so as to render useless ae ea working with sloped spade, back and edge ; chopping is by edge alone.
 * Chaffing is, I believe, a provincial term, but I mean