Original Papers.

HOUSE DRAINAGE.

By JOHN SPEAR.

Medical Officer of Health for South Shields, Jarrow, and Hebburn.

II.

IN an article which appeared in the RECORD of Oct. 14, 1876, I expressed an opinion that, within certain limits, distinct rules might be laid down for the guidance of builders in the construction of housedrainage, and that such rules in respect to all drains communicating with the interior of dwellings, should be rigidly and universally enforced. Before any such desirable end can be attained, however, it is necessary, or at least most desirable, that those engaged in sanitary work, should be of one accord as to the principles on which such rules must be based; and it is in the hope that greater unanimity, than would appear from the correspondence columns of various public journals at present obtains, may be arrived at, that I venture to pen the following recommendations. I do this with all the more confidence, as I find from the report of the medical officer of the Local Government Board, for 1875, just issued, that Dr. Buchanan in the appendix to his report on the outbreak of typhoid fever at Croydon, recommends a plan of drainage, precisely similar in all important details to that which, after careful consideration of all systems that have hitherto found favour with sanitarians, and after considerable experience, I had determined to advocate as the most satisfactory.

In the construction of house-drainage two great desiderata should, I conceive, be kept in view :-(1) the verance of all air communication between the common sewer system and the house drains; and (2) the construction of the house drains in such a manner that no impurities generated within them, or introduced from without, may find their way into the house.

By the attainment of the first object, the air of the drain is charged with impurities derived from one house only, instead of impurities from, it may be, the hundreds of houses communicating with the main sewer, and containing, as these impurities may do, the fatal poison of a dozen different forms of disease. This is a very wide step towards safety, as will be obvious, but it is by no means all that is required. Impurities contained in the private drain itself must be guarded against also. And it must be remembered that it is not the water-closet pipe only that is liable to become impure. Decomposable matter, scarcely less harmful than that of the closet pipe, will be sure to find its way into all drains used for the removal of slop water. If such pipes be of iron, the interior will become roughened by oxidation, and matter will adhere to their sides and decompose; if of other metal, the interior will become greasy, with the same result. Supposing, too, for a moment, that infectious disease be present in the house. A slop-water drain, or a drain from a bath, may, and very probably will, receive the specific infective poison; and this, in the case of defective arrangements, may manifest itself in another part of the house, wherever a communication with the defective drain exists, or perhaps some time afterwards, in a second outbreak of the disease, after infinite pains

and trouble, and much money, have very likely been expended, in many ways, to obviate such a calamity.

The rules, then, that may be laid down are as follows. Their observance should, as I have said, in the case of new buildings, be insisted upon; and they might, I am convinced, with a little ingenuity, and, in some cases, slight alteration, be made to apply to any existing arrangement.

Soil Pipe.-1. The soil-pipe must be disconnected from all other house-drains, receiving only the discharge from the pan of the water-closet.

2. In addition to the usual trap at its commencement, this drain should have a trapping bend in the horizontal part of its course, as it runs towards the sewer; thus cutting off air-communication with the

common sewer system.

3. From the house side of this additional trap a ventilator should proceed directly to the surface, opening at the surface in a convenient spot in the yard or premises.

4. The soil-pipe should be carried up, full calibre, as a ventilating shaft, to the roof.

Discharge Pipes from Baths, Housemaids' Sinks, Scullery Sinks, Hand Basins, Urinals, etc.-I. These may be connected with one common drain, which should always discharge in the open air, above a trapped gully,

2. If the drain be a long one, leading from upper stories, it, too, should be carried for the purposes of ventilation to the roof, thus being open at both ends. The inlets from the house should be trapped.

Overflows, etc., from Cisterns.-These should be in no way connected with other drains. The overflows from the small water-closet cisterns, may conveniently be carried through the external wall, and there be allowed to terminate. From the large cistern, sometimes placed at the top of the house, the discharge pipe, used for running off the water when the cistern requires cleansing, might either be carried into a rain-water spout, when this has no connection with sewer or drain, and if there be no objection to the mixing of the hard and soft waters, or an entirely separate pipe, terminating like the slop-water pipe in the open air, should be pro

vided.

All other drains, more especially those having a variable amount of water passing through them, such as the discharge pipes from closet and bath pans or safes, should terminate in the open air.

The expediency of these rules as to slop drains and overflow pipes will, I think, be at once conceded. It is only in reference to the construction of the soil-pipe that there appears to be any serious difference of opinion. The following diagram will explain, more precisely than words can do, the construction here advocated. The design is taken from the report of Dr. Buchanan, before alluded to, and shows an improvement in detail, not thought of by the writer before seeing the report in question, viz., the somewhat abrupt dip in the pipe, immediately in front of the trapping bend. This, as Dr. Buchanan points out, is of importance, as obviating in great measure any danger of stoppage in the trap.

It is said, I know, that the ventilator at the yard level may be objectionable; but this I have not found to be the case in practice. If effluvium escape it is probably because the pipe has become choked at the bend, in which case the ventilator affords a ready means by which cleansing may be effected. With Dr. Buchanan's contrivance, how

escape rather than it should reach the soil-pipe, where the latter is in close contact with the building, for when this occurs, owing to the superior temperature of the atmosphere of the house, and in spite of the ventilation of the soil-pipe, it is only necessary for there to be a flaw in the pipe, or a defective or weak trap, to determine the invasion of the house by the most deleterious gases. Of this fact I have seen recently several instances. There is a sewer in this neighbourhood which, owing to the admission of chemical refuse (the drainage from old deposits) is occasionally charged to an abnormal extent with sulphuretted hydrogen; and it is found almost impossible to keep the gas from the interior of the houses, where it shows itself unmistakably both to the senses of the occupants, and occasionally in the appearance of their furniture; and this notwithstanding free ventilation, both of the sewer and house-drains. This escape, I believe, is owing chiefly to the easy solubility of sulphuretted hydrogen in water, and the consequent impaired utility of traps; and the reasoning may on this account apply with diminished force in respect of other gases. Still, taken with other instances that frequently come under notice, it shows that there is danger so long as sewer-gas is in the house-drains.

To return to the diagram. It is found that instead of the ventilator in the yard becoming a nuisance, under ordinary circumstances, and when the drains are in proper order, its effect is this: By the natural laws of movement of gases, a constant current of air-pure air, and not air of the sewerswill be passing through the soil-pipe, the inlet being at the yard level, the outlet at the ventilator at the roof; and this is precisely what is required.

The arrangements I have described will, of course, prevent the ventilators of the house-drains acting as ventilators also of the sewers. And this is rather an advantage, for reasons besides those to which I have already referred. Such ventilation is,

I am convinced, although often relied upon by sanitary authorities, almost wholly illusory. The comparatively small calibre of the ventilating shafts, and the consequent large amount of friction which they entail; the lower temperature to which they are exposed in comparison with that of the sewer, and the consequent condensation of watery vapour, and impeded passage of air; together with their necessarily more or less circuitous course, render them, when least needed, and for that single purpose of ventilation-the relief of air tension-of comparatively little avail; when most required, for reasons which I explained in my previous article-the sealing of their ends by the sewage-they are altogether inoperative. The ventilation of the sewers, therefore, must be carried out by a wholly distinct system; in which the ventilators should communicate with the crown of the sewer. The house-drain ventilators, I repeat, can never serve the double purpose: the theory is, as I have shown, opposed to scientific principles; and the sooner certain writers on this subject cease to advocate it the better, both for the cause they wish to serve, and their own reputations.

It may be necessary, as I have said, to modify in some slight degree the above rules under certain conditions. Sinks in sculleries, for instance, are sometimes wholly beneath the level of the ground outside. In houses hereafter built such rooms in the basement should always have an area connected with them, for reasons besides those of drainage. With this area, the drain may be disconnected as advised. In existing buildings, where this arrangement cannot be carried out, the drain should be ventilated on the sewer side of the trap, the ventilating pipe being carried from the top of the trapping bend to the surface; or, better still, an open trapped gully might be sunk to a sufficient depth, outside the house, and the drain connected with it above the trap.

In my own individual experience, I have found perhaps the most difficulty with drains constructed for the purpose of carrying off surface and subsoil water; and although this is not, strictly speaking, house-drainage, the evils that arise through defective construction are the same, and it may not be considered out of place to briefly refer to them. Such drains I have frequently found running from the front of the house, immediately beneath the floor of the basement rooms, to the sewer at the back. They are often most imperfectly jointed; householders and ignorant workmen frequently supposing that, because they are for the purpose of conveying water only, they are powerless for harm. I have seen these drains, although, as I have said, immediately beneath loosely boarded floors, and communicating directly with the main sewer, constructed of common landtiles with open joints, and even, at other times, formed only of an open channel. As might be expected, I have had, on three or four occasions, to attribute outbreaks of disease to this particular defect. Again, it is found sometimes that a 'sumphole' exists beneath the basement floors, for the purpose of collecting the drainage of the foundations; and from which an over-flow pipe usually runs to the sewer. This is a defect even more serious. Even if the overflow-pipe be trapped, as only a variable quantity of water runs through it, the trap is a delusion and a snare. The sewer, consequently, is ventilated directly into the sump-hole,' and from this point there is probably nothing to prevent the gas gaining access to the rooms above. These and similar

defects are often connected with the best of houses; their very presence shows, indeed, that some attempt at sanitary improvement has been made; for, certainly, it is of extreme importance that dryness and ventilation of the soil beneath dwellings should be secured.

Several contrivances, however, may be adopted to meet the necessities of the case, without having sewer-gas laid on to the houses. Areas are rarely of sufficient depth to allow the usual mode of disconnection of house drains to be applied. Deep yard gullies, however, open to the surface, might be provided, as suggested in the case of under ground sinks, the drain being connected at a point above the trapping water, and having, for additional security, a valve trap at its termination; such traps acting well enough when only water passes through them. It would be right to have connected with the gully a second drain, and one through which the flow of water would be more constant, so that the trap might be from time to time renewed. In one or two cases I have advised the necessary disconnection by the interposition, at some point between the house and the sewer, of a short trench in place of the pipe drain; the trench being rendered impervious at the floor or invert, for the proper guidance of the water, and then filled in with pervious materials through which the water may percolate. By this means any current of sewer air will be directed out of the line of plane in which it is travelling, it will be broken up, and its passage to the house impeded. A valve-trap should be inserted into the drain on the house side of the channel; and the proper ventilation of the sewer in the immediate neighbourhood attended to. Valve-traps it should be remarked, when applied to deep subsoil drains are specially useful, as they not only form a barrier to the passage of sewer gas, but they prevent the backwash of sewage in times of flood, an accident that must be carefully guarded against in the case of deep drains in low-lying situations.

The plan of covering the foundations of houses with concrete, and then providing for thorough

ventilation between the concrete and the boards

of the floor, always of great utility, is, obviously, specially advantageous when drains are situated beneath the house. It is too much, however, to expect that builders will carry out this work voluntarily in the case of ordinary houses, and it may be a question whether by-laws should not be made requiring it to be done under certain circumstances. Section 157, subsection 2, of the Public Health Act, gives the required power, and I have lately induced the authority of one of my districts to agree to a by-law, regulating the structure of the foundations of such houses as are built on refuse.

I fear, however, that this is a digression. To return to the subject of my paper, I would express a firm conviction that, although much of course must always depend upon the skill of the workman, it is ignorance or neglect of the principles I have advocated which leads to those lamentable results of defective drainage now so often recorded. If, on the other hand, these principles be adhered to, householders will, in very great measure, be independent of careless and unskilful workmanship.

AN order has been issued for the formation of a loca board at Abertillery, to consist of nine members.

DRY CLOSETS.

AT one time the term dry closets was only applied to earth-closets, now it has come to be the designation of almost every kind of closet in which the receptacle is movable, or in which an attempt is made at deodorisation, disinfection, absorption, or separation. The passing of the Rivers Pollution Bill has given dry closets a fresh impetus, and now we find sanitary authorities pretty generally considering whether they cannot escape their sewage difficulties by falling back upon some one or other of the numerous so-called dry systems of conservancy. This feeling is not confined, as might at first be expected, to small towns and rural populations, but towns of the size and importance of Manchester, Birmingham, Salford, Halifax, Rochdale, etc., are busily engaged in extending the use of dry closets and in opposing by all legal and moral means in their power the further introduction of water-closets. It seems, indeed, as though the old midden, at all events, was doomed, and that is a consummation devoutly wished for by all sanitarians, but how far the sewage problem or difficulty will be solved or assisted remains to be seen. The weak point in all the dry closet schemes appears to be that slop-water and liquid house refuse in general remains unprovided for. Side by side with the disposal of human excrement should run a system of slop disposal and collection, but none of the closet companies or advocates have as yet grappled this difficulty. The Liernur system alone, if we may except or include the satellite Roberts' plan, includes both slops, excrement, and other liquid wash, but this system has not yet been proved in England. English sanitarians cannot yet believe in its cleanliness. 'Water-closets without water' sounds paradoxical; and while it is conceivable that the slops, etc. would, in the lower stages, supply its place, it seems highly probable that the soil pipes leading from closets in the upper storeys, especially of warehouses, factories, etc., would become foul to an extent inadmissible in England. However, a Liernur system for slops and a dry system for closets might run side by side, and for large or small houses we are inclined to think that Liernur or Liernur and Co. (as a combination might be christened) will be the ultimate solution of all difficulties. It is rather strange that while, so far as we know, Liernur has not found favour here, modifications of the system have been actually tried or proposed. Mr. Roberts, though a young engineer, has made converts; and Mr. Fowler, the borough engineer of Salford, has patented a modification of Liernur, in which he follows his leader in discarding water, but strange to say he discards the collecting tanks also, and goes straight into and through the sewers with his discharges.

Truly rural places ought to be in no difficulty, and certainly there is no excuse for the pollution of rivers by rural populations. Rural sanitary authorities have only to carry out the powers they now possess and compel or undertake systematic scavenging, together with the construction of properly built cesspools, and their sewage difficulties vanish. Of course, at first, there would be a little trouble experienced in making people empty their receptacles at short and fixed periods, but a few months' determination would overcome every obstacle. Agriculture would be benefited, and there is no doubt but that the value of the manure hitherto wasted would reconcile people to the extra trouble incurred.