Part 10

Cast-iron drains are now very often used in place of earthenware pipes, and there is a great deal to be said in their favour, especially since the invention of several processes whereby the interior is prevented from rusting and scaling. Pipes of this material are useful underground in rows of houses, and wherever straight lines of delivery are obtainable, and compared with drain pipes of earthenware, with their necessary surrounding of concrete, they would prove not more expensive. Unfortunately, however, this system cannot always be adopted, unless the house has been planned with a view to this method of drainage; and in most houses it will be observed that the pipes would have to run in front of fireplaces and across doorways if above ground. When iron piping is used, great care should be taken with the jointing, to see that it is properly packed, and with material calculated to last as long as the pipe itself. Iron pipes with merely leaded joints are subject to galvanic action, whereby the iron, sooner or later, thins out by corrosion, the iron perishing by “abnormal local oxidation,” as has been very forcibly stated by B. H. Thwaite. When iron is contiguous with lead, a galvanic action is set up, and, the latter being electro-negative to the iron, the iron suffers. There ought, therefore, always to be an assistant packing in the pipe, and the majority of engineers make use of this. Eassie advises in addition, a luting of Portland cement with the other materials, which may include a previous stuffing of fibrous packing material together with the old-fashioned iron filings and acids.

Given the best kind of drain to lay down, there is still the question as to where to lay it, and here lamentable errors are frequently made. The chief fault perpetrated in this particular is the laying of drains inside a house, when they might just as easily have been laid outside. When a drain is laid down, care is exercised to get the pipes as much as possible in straight lines; and at each departure from a straight line a manhole is formed, enabling any one to inspect the drain at any time, by lifting the manhole cover. If a lighted candle is placed at the bottom of the drain in the manholes, the freedom of the drain from obstructions can be ascertained by looking from manhole to manhole. These inspection chambers should be placed at every departure from a straight line, and where several drains junction together; thus each drain delivery is open to sight, and rods can easily be introduced up the drain pipe should any obstruction occur. These inspection chambers are always best protected by an iron manhole cover, fitting down perfectly into their iron frames, which are sunk into the stone floor.

Most houses in connection with a large brick sewer have a “flap-trap,” just where the house drain enters into the sewer; this flap opens to allow the house sewage to enter the sewer, whereupon it should immediately close again to exclude foul air and rats from invading the house. They sometimes, however, do not shut closely, and in that case their action for good is almost at an end. A householder can have an occasional inspection made of the trap by the sewer men, by paying a small fee to the vestry.

_Precautions after Floods._--Dwellings which have been invaded by the waters should receive special care, so that those whom the flood has expelled should not occupy them before they have been made sufficiently healthy for habitation. They should first be cleaned out as quickly and thoroughly as possible, and freed from all dirt and debris deposited in different parts by the water. Continuous aëration and the most active ventilation are the best and most energetic agents. To increase these as much as possible, where it can be done, a large fire should be maintained on the hearth, and the doors and windows opened, so that the light and heat of the sun may contribute their part to purifying the air. At the same time care must be taken to dig a ditch 10-15 in. deep around each house, whose interior is in many cases below the level of the ground. It will also be well, after having torn down all plastering, which will be in a bad condition, to scrape to their bottom all joints in the walls, and to replaster them in the parts of the house most injured, and where bad deposits have principally accumulated. The floors, where such exist, should be carefully attended to, and the soil under them covered with a disinfecting substance, such as pounded charcoal, or sand, or else with an impermeable material, such as flagging, paving blocks, cement, &c. Where the house is several stories high, the top stories should be the first occupied.

Great precautions should also be followed in the treatment of certain articles of furniture, such as beds and mattresses, which must be renovated or replaced, and which should never on any account be used until thoroughly dried. Sanitary treatment, such as adopted for houses, should be applied with no less vigilance to stables and barns. One peculiar feature it is important to note, though it can only be accidentally produced: it is the possible alteration of the water of wells and springs of potable water, in whose neighbourhood matter in a state of decomposition may have been deposited, or piles of excrementitious and organic debris, or sources of water supply which may have been contaminated by the contents of privy vaults. Attention should be directed to this danger. To disinfect cellars into which, by agency of the inundations, the contents of privy vaults may have penetrated, commercial zinc sulphate may be used, either by sprinkling it in powder in the cellar, or by watering the ground when the water has gone down with a concentrated solution of this salt. Concentrated solution of iron sulphate does well, but the disinfection is not so complete as with salts of zinc; it is, however, cheaper.

=Ventilation.=--The objects of ventilation are twofold--first to get rid of the poisonous gas (carbonic acid) exhaled from our lungs, and second to furnish a supply of life-supporting gas (oxygen, as it exists in fresh air) to our lungs. For healthy living, every adult individual requires at least 1000 cub. ft. of space, or a room 10 ft. square and 10 ft. high; into this room should pass 3000 cub. ft. of air every hour.

In dwelling-rooms, and especially in bedrooms, the fireplace should always be left unclosed, and the flue or damper open for ventilation. The windows should pull down from the top, and a piece of wire gauze should be fixed along the open space at the top; or a pane of glass should be perforated with holes capable of being closed in stormy weather. All rooms, and especially sleeping apartments, should be well aired during the day.

A good and simple test for impure air is to take a clear glass bottle with a glass stopper, holding about 10 oz., and wipe it carefully inside and out. On entering a room, the air of which you wish to test, stuff a linen cloth into the bottle and rapidly withdraw it, so as to allow the air of the room to enter the bottle. Then carefully place a tablespoonful of clear lime water in the bottle, and replace the stopper. Shake it for a few minutes; then, if the air is pure, the lime water will remain clear. If bad, and loaded with carbonic acid, the lime water will become turbid, or even milky. This is because lime and carbonic acid together form chalk, which gives the milky appearance. It must be remembered that this test has no reference to the ammonia which often exists abnormally in the bad air of towns, nor does it indicate the presence of disease germs or poisons due to paint, wall-paper, &c.

A fire in an open fireplace is a good ventilator in a way. We may ventilate a room easily by raising the lower window sash, and by placing inside the frame a piece of wood 3-4 in. high, and 1 in. in thickness, and reaching from one side of the frame to the other. When the inside sash is brought down to rest on this piece of wood, it is thus raised 3-4 in. A current of fresh air moves inwards and upwards to the ceiling between the sashes, and if a piece of wood or glass, sloping upwards, be attached to the top of the lower sash, the current of air will be sent upwards to the ceiling, whence it will diffuse itself through the room.

Draughts must be avoided; and it is wonderful how easily they may be prevented. Pettenkofer has shown that if air at ordinary temperatures does not move at a greater rapidity than 1½ ft. per second, its movement is not felt. What is needed, therefore, is some kind of screen that will not prevent the entrance of air, but that will break its force, divide its currents, and make it flow unfelt into the room.

Perhaps the simplest plan of effecting this is the following: Open your window at the top to whatever degree is necessary to prevent closeness in the room, but if there is a draught open it wider still; place a little loosely-packed cotton-wool between the upper and lower sash, and in the open space above the upper sash place a strip of perforated zinc, with its lower edge turned upwards, so as to direct the draught towards the ceiling. If there is still too much draught, open it still wider, but fasten in front of the perforated zinc a screen of gauze containing loosely-packed cotton-wool. It is noteworthy that there must be a sufficient current to carry the air upwards along the slanting piece of zinc, and towards the ceiling, otherwise, as Corbett has pointed out, the cold air will trickle over the edge and cool the feet of the inmates of the room.

In the hot months it is worth while to bear in mind the plan adopted by Martin in order to keep the rooms of the sick in a state of freshness. This consists in opening the windows wide, and then hanging wet cloths before them. The water, as it vaporises, absorbs the heat, and lowers the temperature of the apartment by several degrees, while the humidity which is diffused renders the heat much more supportable. By adopting this plan, the inmates find themselves, even in the height of summer, in a freshened atmosphere, analogous to that which prevails after a storm. This fact is well known to and utilised by the natives of India. Another plan is to close all windows facing the sun and cover them with blinds or curtains, to exclude the sun’s rays and the heated external air. Carpets may be replaced by matting, and the latter may be sprinkled with plain or perfumed water.

In very cold weather it is equally desirable to close all cracks and chinks against the influx of draughts. Cracks in floors, around the skirting board, or other parts of a room, may be neatly and permanently filled by thoroughly soaking newspapers in paste made of 1 lb. flour, 3 quarts of water, and a tablespoonful of alum, thoroughly boiled and mixed. The mixture will be about as thick as putty, and may be forced into the cracks with a case knife. It will harden like papier-maché. Old windows that do not close tightly may be remedied by smearing the edge on which they close with putty, and that of the sash with chalk, and then closing them as firmly as possible. The putty will fill up the crevices, and the excess pressed out at the sides may be removed with a knife, whilst the chalk prevents adhesion to the sash.

A system in very general use is Moore’s patent glass louvre ventilator, consisting of a number of louvres (or slips of glass), which can be opened to any angle up to about 45°, thus always directing the incoming current of air upwards. They are easily regulated and secured by a cord, which when released allows the louvres to close practically air-tight. Moore’s circular glass ventilator, which consists of (usually five) pear-shaped openings, neatly cut in the window square, and fitted with a circular glass cover with corresponding holes working on a centre pivot, are also very effective for admission or extraction of air. Moore’s sliding ventilator consists of oblong vertical holes, with the cover sliding between guides horizontally, the principle being the same as in the circular ventilator, but it is more suited for the top of shop fronts or shallow fanlights. These are all made by J. Moore and Sons, Sekforde Works, St. James’s Walk, Clerkenwell Green, E.C.

Another simple method of admitting fresh air to a room consists in leaving an aperture in the external wall, at a level between the ceiling of one apartment and the floor of the room immediately above, then to convey the fresh air through a channel from the external wall to the centre of the ceiling of the apartment below, where the air can be admitted by an opening, and dispersed by having a flat board or disc to impinge against, suspended 4 in. or 6 in. below the opening of the ceiling, and so scattered over the room. The cold air, however, thus admitted, plunges on the heads of the occupants of the room and mixes with the hot air which has risen near the ceiling. A top window-sash lowered a little to admit fresh air has the same disagreeable effect, the cold air being drawn towards the floor by the chimney draught, and leaving the hot air to stagnate near the ceiling. In any siphon system placed vertically the current of air will enter by the short arm, and take its exit by the long arm, and thus the chimney flue acts as the long arm of a siphon, drawing the fresh air from the nearest opening. Fresh air may be introduced through perforations made in the woodwork of the bottom rail of the door to the room, or through apertures in the outer wall, admitting the fresh air to spaces behind the skirting board, and making the latter perforated. The only objection to this plan is the liability for vermin to lodge between the skirting board and the wall. This may be prevented by covering the outside apertures with perforated zinc, but such covering also helps to keep out the full supply of fresh air.

Butler recommends, while admitting the cold air through side walls near the floor level, and allowing the foul air to escape at the ceiling, that the fire draught should be maintained quite independent of the air inlet to the room, the requisite amount of air for combustion being supplied by a separate pipe led through the hearthstone with its face towards the fire, the latter acting as a pump, which is sure to procure its own allowance from the nearest source; thus the draught which would otherwise be felt by the fire drawing its supply from the inlet across the room is considerably reduced. The foul air may enter the ceiling in the centre, and be conducted by an air-flue either to the outside or to the chimney. The chimney is the best extractor, as its heated condition greatly favours the ventilating power.

Dr. Arnott was one of the first to draw attention to the value of a chimney as a means of drawing off the foul air from the interior of an apartment. He invented a ventilator consisting of a well-balanced metallic valve, intended by its instantaneous action to close against down draught and so prevent the escape of smoke into a room during the use of fires. If the fire is not alight, what is known as the register of the stove should be closed, or a tight-fitting board placed in front of the fireplace, with the adoption of all chimney-ventilators fixed near the ceiling.

Harding’s ventilators are better known in the north of England than the south. They are recommended by Pridgin Teale, surgeon to the General Infirmary at Leeds, as a means of securing freshness of atmosphere without draught, and free from all mixture of dust, soot, or fog. The outside air is conducted through a grate and aperture in the wall about 7 ft. 6 in. above the floor level, where it is made to pass through a series of small tubes fixed at an angle of about 30° with the wall. The currents of air are said to be compressed while passing through the tubes, but to expand and diffuse in all directions as soon as they are liberated into the apartment. In all filtering arrangements it must be remembered that if air is to pass through a screen or filter without retarding the current entering the room through a tube, the area of the screen must be greater than the area of section of the tube. This can be effected by placing the screen diagonally within the tube which admits the air. In some buildings the filter is dispensed with, and the apparatus is used simply to diffuse the air as it enters the room. An outlet for the vitiated air is provided by the chimney flue, either through the fireplace or by a mica valve placed in the flue near the ceiling. In rooms where flues do not exist an air extractor is provided, consisting of two perforated cones and a central tube. The external air impinging upon the perforated cones is deflected, creating an induced current up the vertical tube, drawing the foul air from the interior of the room, and expelling it through the perforations. In fixing the extractor, a wooden base or frame is placed on the ridge and covered with lead to make it watertight; the extractor is then placed over this and fixed in the ordinary manner. A small inner cone is provided simply to prevent rain from getting into the tube. Harding’s extractors are so designed that they may be easily fixed inside an ornamental turret without in any way affecting their action. They can be obtained in London from Strode & Co., at prices varying from 15_s._ to 6_l._ and upwards. Their action is illustrated in Fig. 27: _a_, wall; _b_, grating outside; _c_, filter.

Another system for admitting fresh air into a room, free from fog and other impurities, is that recommended by the Sanitary Engineering and Ventilating Co., 115, Victoria Street, Westminster. They provide for the introduction of fresh air in vertical currents by means of a suitable number and disposition of vertical tubes, varying in size, section, and weight according to each special case. The current can be regulated in amount by throttle valves, and the heated or vitiated air is removed by means of exhaust ventilators, placed directly over the roof or in connection with air flues and shafts. The exhaust ventilator is thus described by the makers: There are no working parts to get out of order, and no attention is required to ensure its constant action. In this respect, a great improvement is claimed over the numerous forms of revolving cowls, which require occasional lubrication, otherwise the working parts become corroded and the cowl ceases to act. They are made of circular or rectangular section, or other shapes to suit special circumstances. One great merit of the system is the element of length which is introduced by means of the tube arrangement, and thus a current is continually passing which diffuses itself over the room. The system admits of a patent air-cleansing box being built into the wall at the foot of the tube, fitted with special deflector plates and a tray to hold water or, when necessary, disinfectants. When the arrangements of furniture or fittings in a room preclude the use of vertical tubes fixed near the ground, they recommend the substitution of a ventilating bracket fixed at 6-7 ft. above the floor. This bracket may contain an air purifying or cleansing box; if required, a valve is provided for regulating the admission of fresh air, and a 9 in. by 6 in. hinged air grating to cover the opening outside. The air-cleansing box is illustrated in Fig. 28: _a_, inside of room; _b_, floor; _c_, trough or tray for holding water or disinfectant fluid; _d_, tube.

Boyle’s patent self-acting air-pump ventilators are well known, and are found to answer well in their continuous action under all varieties of wind pressure; they are often adopted without any inquiry being made as to the scientific principles on which they are constructed. They consist of 4 sections, each acting independently of the other. The exterior curve baffle-plate prevents the wind blowing through the slits formed in the immediate interior plates, and tends to concentrate the current. These interior plates are curved outwards, so as to take the pressure off the vertical slits, which form a communication with the internal chambers, through which the air impinges on inner deflecting plates, and is further directed by the radial plates. The external air impinging on the radial plates is deflected on to the side plates, and creates an induced current. In its passage it draws the air from the central vertical chambers, expelling it at the opposite opening. The vitiated air immediately rushes up the shaft connecting the ventilator with the apartment to be ventilated, extracting the air and producing a continuous upward current without the possibility of down draught. The partitions separating the chambers prevent the external air being drawn through the slits upon which the wind is not directly acting. The whole arrangement being a fixture, with no mechanical movement, it is never liable to get out of order, and the apparatus can be easily fixed over a wood base or frame covered with zinc or lead to secure a good water-tight connection. Where Boyle’s ventilators are used the air is renewed imperceptibly, the vitiated air being extracted as rapidly as it is generated.

A somewhat similar arrangement to Boyle’s ventilator is patented by Arnold W. Kershaw, of Lancaster, and consists of 3 rims of deflectors or plates with openings in each, so arranged that the openings in one rim are opposite the deflectors in the next inner or outer rim, the effect being that whatever the direction of the wind, it passes through the ventilator without being able to enter the central shaft, and in passing creates a partial vacuum, which induces an upward current in the upcast shaft without the possibility of down draughts. Both Boyle’s and Kershaw’s roof ventilators are suitable for fixing in ventilating towers or turrets. While Kershaw’s is somewhat simpler in construction, Boyle’s is said to possess the additional advantage of preventing the entrance of snow by the curve in which the inner plates are fixed. In the case of chimney flues where there is any obstruction that breaks the wind and produces a swirl, such as would be caused by close proximity to higher buildings or raised gables, a down draught may be prevented by the use of a properly-constructed chimney cowl. Kershaw’s chimney cowl is a modification of his pneumatic ventilator, and consists of deflecting plates so arranged that there is no possibility of a down draught. Boyle’s chimney cowl is better known than Kershaw’s, and is very effective. It consists of deflecting plates so fixed that if a body of air is forced in at the false top, instead of passing down the vent, it is split up by an inner diaphragm, deflected over the real top, and passed over at the side openings, thus checking the blow down and assisting the up draught. Kershaw’s patent inlet and air diffuser consists of a tube connection between the outside and inside of an apartment rising vertically on the inside, the upper extremity having radiating plates, which diffuse the incoming current. Generally speaking, a sufficient amount of fresh air enters under the door to a room or between the window sashes or frames; but in apartments where doors and windows fit tightly, some arrangement for the admission of fresh air becomes indispensable. In this climate, during 7 months of the year, the external air is usually too cold to be admitted directly into the room.