CHAPTER XIV SANITARY SURVEYS AND REPORTS (Part 1)

CHAPTER XIV SANITARY SURVEYS AND REPORTS Vital Necessity for Good Drains. Amongst the general public there is usually too much of the feeling “out of sight, out of mind” in regard to sanitary matters. Householders make the great mistake of not looking on the drains as a part of the dwelling, and a delicate part at that. The drains stand in the same relation to the dwelling as the bowels to the human body. They carry off waste matters which it would be injurious to health to retain in the structure. A leakage of the bowels causes instant injury, whereas the injury due to a leakage of the drains is more gradually felt, but that is only because the proportions between the bowels and the body, and those between the drains and the house are different. In time, the ground adjacent or subjacent to the house becomes sewage sodden, giving off noxious emanations, to say nothing of its possibly injurious effect on any water supply there may be in the vicinity of the drain. Chief Items in a Complete Sanitary Survey. The conditions which should be fulfilled by a really sanitary building have already been given under various headings, and there would be no useful purpose served by repeating them here. They will have shown, however, that in making a sanitary survey of a house, there are many points which require consideration; such as the general arrangement of the building, and in particular the relation between the position of the sanitary fittings and that of living rooms and bedrooms; ventilation, dampness, water supply, sanitary fittings, drainage, etc. Let us consider in detail the procedure in making the inspection, the method of booking the notes, and that of writing the report on such information as is obtained. A fundamental principle in sanitary survey work is that of taking nothing for granted. The surveyor may find a plan of the drainage at the house; he should accept it as information, but must satisfy himself as to its accuracy. He often finds a gardener or odd man about the house, who is most anxious to give him informa- tion in reference to such matters as the courses of the drains, but again such evidence should be verified. If in inspecting, say, the water supply he finds a casing over some of the pipes, such easing should be removed and the pipes traced from end to end. 434 SANITARY SURVEYS AND REPORTS Testing the Drains. One of the most important things incidental to the survey will be the testing of the drainage system. There are four principal methods of testing. namely: 1. The Olfactory or Odour Test. 2. The Smoke Test. 3. The Water or Hydraulic Test; and 4. The Air or Pneumatic Test. The Odour Test. The odour test is a very poor one, but one must not overlook the fact that occasionally the circumstances are such that the other tests cannot be applied. It may then be useful. The test is only suitable for soil and waste pipes and the joints around fittings, and can be applied in either of two ways. One is that of using a chemical drain tester. There are many varieties of these, consisting of packages of phosphorous compounds or other eyil-smelling substances. They are put up in many forms, and consist of receptacles from which the smell-producing substance is ejected after passing through the trap. They are furnished with fairly long lengths of string, usually coiled round them, by means of which the receptacle can be withdrawn after use. An example of this kind of appliance is shown in Fig. 436 which illustrates what is known as a Kemp tester. It consists of a thin glass tube containing a chemical compound. The substance is kept in the tube by a cap and rubber washer, a spiral spring, 5, around the tube tending to force the cap off. This is prevented, before use, by a strip of paper, P, which passes over the cap and down the two sides, to which it is fastened. The whole appliance is only about 2 inches long. To apply a test, it is flushed through the trap by a bucketful of water, hot if available; the hot water rapidly softens the paper strip and releases the con- tents. This example is illustrated merely to show the nature of such apparatus; there are many others made for the same purpose. The other method of applying the olfactory test is by placing oil of peppermint in a bucketful of boiling water, about one and a half ounces of the oil to a quart of water. The liquid should be mixed and passed through the trap by an assistant, the surveyor himself keeping away during the process, as the smell is very pungent and readily clings to one’s clothes. He then goes from room to room searching for traces of the smell which would come from leaky joints in the pipes or fittings or from an insufficiently sealed or unsealed trap. The Smoke Test. The smoke test can be used for pipes below as well as those above ground, but it is not a satisfactory test for underground drains. In the case of defects above ground the SANITARY SURVEYS AND REPORTS 485 Tk , mn 436 =lelel=lels \ KEMP TESTER illalalilita I ccna FOR ODOUR S\N 7/7 COC ETT 7/777 438 DISC PLUG FOR WATER, C AIR OR SMOKE TESTS INTERIOR WORKING PARTS OF SMOKE MACH/NE FOR SMOKE OR A/R PRESSURE TESTS VASSAR EIALAIDDDIDUIIIEEAIDEOODOLEIILIRBBAEEEDD 440 2 441. TWO FORMS OF BAG PLUG FOR WATER, A/R OR 442 BEATTIE WATER TEST GAUGE TO Z, MEASURE DEPTH OF WATER SUR- FACE BELOW TOP OF MANHOLE. SMOKE TESTS 443 GLASS GAUGE (OR o% JONES INDICATOR) *¥) TO SHOW WATER LEVEL /N DRAIN AT LOWER . WHEN LOWER THAN /NVERT OF TOP MAN- 486 SANITARY SURVEYS AND REPORTS smoke is readily visible, apart from the smell, and in the case of a defective drain having only a shallow covering of porous soil the smoke will readily issue at ground level. With a considerable depth of earth over the pipes, or earth of a dense, damp nature, such as clay, however, the smoke will not find its way through. To facilitate its doing so, a probing iron is sometimes used, consisting of a pointed iron rod a few feet long, with a handle. It is used by walking over the course of the drain and forcing the rod down into the soil at frequent intervals so as to leave holes for the smoke to rise. The probing iron is also used for another purpose, that of probing the ground to locate the course of drains whose position is unknown or uncertain. The smoke can be produced in two ways: (1) by a smoke rocket or smoke case, and (2) by a smoke machine. The former is shown in Fig. 487, and consists of a cardboard tube about 8 inches long and 1} to 2 inches in diameter, the end being closed with paper. It has two wooden strips or fillets fixed to it, as shown at S, with a small nail through the middle. These should be turned round so that they are at right angles to the case, in order to keep the rocket off the invert of the drain, clear of the sewage. On lighting the paper and fuse at the end, a dense volume of smoke issues. The case should be removed from the drain after use. The drawback to the use of smoke rockets is that the smoke cannot be produced under pressure, and to overcome this difficulty many forms of smoke machines have been introduced, differing largely in detail. The broad principle underlying them all is, however, the same; that of producing smoke under pressure by burning oily cotton waste, thick brown paper steeped in creosote oil, and other substances. Fig. 4839 shows, diagrammatically, the essential parts of such a machine. S.C. is the smoke chamber, having a water jacket round it, a dome, D, fitting well down into the water space to provide a seal against the escape of smoke. Near the bottom of this chamber is a grating on which the smoke- producing substance is placed. The pipe for the conveyance of the smoke (S.P.) passes down the centre of the chamber, the inlet being near the top as shown. Alongside the smoke chamber is a double bellows, B, actuated by a lever, L. By this means air can be pumped through the air pipe, A.P., to the under side of the grating. The lever must not be worked too rapidly or it may cause the material to blaze instead of smoulder, with a conse- quently diminished amount of smoke. A pressure gauge is some- times added at G in order to register the pressure applied. SANITARY SURVEYS AND REPORTS 437 Drain Plugs. In testing a soil or waste pipe, the drain should be plugged at the nearest manhole. This is sometimes only roughly done by means of wet cloths placed around the flexible pipe which is attached to the outlet of the machine, but it is far better to use a proper drain plug. There are two principal types of plug, (1) that consisting of a rubber ring capable of being expanded, and (2) that consisting of a rubber bladder which can be inflated by means of a small hand pump, and encased in coarse canvas to strengthen it and give it a great gripping power. There are many varieties of each type, and it is not proposed to deal with them all; in fact it would serve no useful purpose to do so. Fig. 488 shows a section through one variety of rubber ring plug, consisting of two circular dises of iron which can be forced together by means of a wing nut, W.N., thus causing the expansion of the rubber ring, R.R. A screw cap, C, is provided at the outer end, which can be readily removed by means of the projecting lugs shown, either for the purpose of attaching a smoke pipe or for releasing the water when used for the water test. The original form of rubber ring was of circular section, but this did not give a good grip to the pipe, and later developments of this type have all tended towards giving greater gripping surface. The best examples of this type, however, do not give such an effective closure to the drain as a good type of bag plug. The earlier forms of bag plug were of spherical shape, but these are not now so extensively used as those of cylindrical shape. Fig. 440 shows a simple form of bag plug in position. It is inflated by means of a hand pump similar to a bicycle pump, but of stronger make, and after inflation the small tap shown can be turned off. It will be obvious that such a plug will not only accommodate itself to any irregularities in the pipe better than a rubber ring, but will also give a much larger gripping surface and therefore a firmer hold. A better form of bag plug is shown in Fig. 441. It has two brass ends, with means of attaching a string or wire, W, in order to per- mit of its being pulled either way, up or down the drain, before inflating it. A brass tube passes right through the bag, with a connection at C which can be used for attaching either the nozzle of the smoke machine, or a small tap to let the water out after a water test. The bag is inflated through a small pipe, A.P., and is closed after inflation by leaving on the tap of the pump. Applying the Smoke Test. In applying the smoke test to a drain, the latter should be plugged at either end so as to form a closed chamber into which the smoke may be pumped. In the case of a 438 SANITARY SURVEYS AND REPORTS soil, ventilating, or waste pipe it is a good plan to test first with the top of the pipe open, and then, if possible, with it closed by means of wet cloths. The first test makes it possible to see if there is any blockage in the pipe, and the second puts a certain amount of pressure on the joints. The smoke test may be re- garded as satisfactory for an uncovered drain, but it is not suffici- ently severe for a covered one, whether new or old. Care is necessary in the use of smoke rockets, as fumes of a suffocating nature are liable to accumulate at the bottom of the manhole. The Water Test. We come next to the water or hydraulic test. It has often been argued that this test is an unfair one, as it puts a greater strain on the lowermost end of the drain than it does on the uppermost. This argument has some justification, but any drain may become blocked and is most likely to do so at the intercepting trap, in which case the water test will be at once applied naturally, the only difference being that the water in this case will be foul, with consequent danger in case of leakage. It has been argued that the water test is not a fair one for other than new drains. The by-laws of local authorities all require new drains to be watertight, the inference being that unless they are so there is injury or danger to health. If it is necessary for a new drain to be watertight in the interests of health, it is equally so for a drain which is no longer new. The argument that the water test is not a fair one for old drains raises the proposition that while it is necessary for a drain, when new, to be watertight, there comes a time in the existence of that drain when that state of things is no longer necessary, but exactly how long after construction that time occurs is a point which I believe no one has yet had the courage to state. One is well aware that perfect drains become imperfect, and that there are many substantial reasons why this is so, such as, in the case of our large towns, the vibration due to heavy traffic, but that does not alter the fact that a surveyor who allows a client, on the strength of his report, to enter into occupation of a house, the drains of which are not watertight, incurs a grave responsibility. Broadly speaking, the water test is applied by plugging the lowest point on the drainage system and filling the drains with water until it stands at a depth of say not less than two feet in the upper manhole, a subsidence of the water indicating a leakage. The “head” of 2 feet mentioned should be looked upon as a mini- mum and the local by-laws may require a greater head. The B.S. SANITARY SURVEYS AND REPORTS 439 Code of Practice on Building Drainage (which is advisory only) advise a head of 5 feet at the upper end of the glazed ware drain under test, maintained for at least 10 minutes. If there is con- siderable fall on the drainage system it is wise to test it in sections, and wherever the system has several manholes it is advisable to test the length from one manhole to another, working downwards from the upper end, the object of this being to utilise the water from the upper lengths for the testing of the lower. In any case in which there are gullies at a lower level than the water in the manhole, they should be plugged in order to prevent the water issuing from them. Relationship between ‘Head of Water’ and ‘Water Pressure”’, ‘Head of pressure” is simply the height of a column of water, in lineal feet, above the point at which the internal strain or pressure is to be recorded. Provided the water is not flowing, the pressure in the supply pipe, at the point just behind the bathroom tap, is dependent on the number of feet, measured vertically, from the tap to the water surface in the service tank in the cistern room or loft. If this height is 10 feet, then the pressure at the tap, when shut, may be said to be 10 feet head. This may be translated to pressure per square inch by multiplying the “head” by 0-484, so “10 feet head” may be described as 4-34 lb. per square inch, and owing to the laws of hydraulics, this pressure operates upwards, downwards, left and right and indeed in every direction. The 5 feet head mentioned above thus indicates a pressure of 2:17 lb. per square inch. Means of Measuring Subsidence. Great care is necessary in observing the water level and noting whether it subsides. If the sides of the manhole are of absorbent material, there is bound to be a drop in the water level owing to the absorption. In such a case the production of exact results is a matter of difficulty, con- siderable experience being needed in reference to the allowance for absorption. If the manhole sides are of non-absorbent material, the depth of the water surface below the top of the man- hole can be accurately measured and noted. Anything like a chalk mark, or piece of stamp paper, as an indication of the original level of the water, is of little value, as it can be easily tampered with. The depth should be accurately measured down from the top and the figure booked. A neat contrivance for this purpose is that known as the Beattie water test gauge. It is shown in Fig. 442, and consists of a horizontal bar carrying an upright sup- port for a small spindle, which passes through horizontally and has a milled-headed wheel, S, at one end, and a small drum, on 440