the air, being warmest on the sunny side of house, will have expanded and become lighter, and so surely as the heavy side of the balance weighs down to earth and sends up the lighter scale, so surely, and on the same principle pre- cisely (the universal attraction of gravity), will the heavier column of air send up the lighter column. It will be well, therefore, to arrange your inlet pipe as low as possible and in the coldest position, shaded from sunshine, and your outlet extractor vent-shaft as high as possible, free from all blow- Fio. 106. — Single mica flap-valve for vertical air inlet. <Callout type="tip" title="Optimal Positioning">Place air inlets low and shaded to ensure effective ventilation.</Callout> Fig. 107. — Double mica flap-valve for vertical air inlet. Fio. 108. — Double mica flap- valve for horizontal air inlet. Fio. 109. — Ornamental quadruple' mica flap- valve, showing also back view and construction of the mica valves, hung on copper loops, and moving with the slightest breath of air to open or close. down action of wind, and in as warm a comer as you can find for it, avoiding all needless bends. The position of air outlet or inlet cannot be definitely settled here, but must be varied to suit the various con- struction of buildings. The plumber, by keeping in mind the cause of the movement of air, can hardly fail to place his vent-pipes and inlets so as to give the desired ventilation. The inlet fresh-air opening must in some cases be pro- vided in an enclosed yard or area, and occasionally these areas have windows or doors opening on them, through which any back puflf of odorous air happening to come from the inlet caused by a reversed current, might be drawn into the house. Endeavour, in the first instance, to find a better position for your inlet; but if you fail there, two courses are open to you. One of these is to place one of the mica flap-valves here illustrated on the inlet mouth. If you take care that the opening of the inlet is not reduced in area no injury is done to the inlet, and the same volume of air will enter as if no valve was employed ; and in case of back puff or draught the mica flaps instantly close by the action of the air upon them, and no inconvenience is caused. Some of the cowls employed in practice are very com- plicated. All revolving cowls require constant attention, and as they are usually fixed high out of reach on top of a roof, that necessary attention and lubricating involves the double risk of injury to slates and gutters and of breaking the workman's neck. If they are neglected they become fixed, and stop or reverse the draught, instead of helping it upward. Take any revolving or Archimedean cowl or extractor, and watch how slowly and feebly the inner Archimedean screw revolves in any ordinary breeze, and judge how little effect it can have upon the air in the tube. Do not allow yourselves to be deceived into the belief that any particular form of extractor is powerful from the 188 DOMESTIC SANITARY DRAINAGE AND PLUMBING. toy experiments with a little model fixed on a glass tube generally produced by toutere for orders, because the force of the breath as applied in these experiments is out of all proportion to the force of wind upon a cowl in action, and you can produce the effect of causing the morsel of light cotton wool generally provided to rise in these glass tubes if you remove the model extractor top altogether and blow across the end of the glass tube. In many instances the effect is more marked with the plain open tube. These illustrations (Figs. 110-112) show three forms of useful soil-pipe extractors formed on common-sense prin- ciples. The three shown without any top, having a light Fig. 110.— Covered extractor. Fio. 111.— Covered extractor. Fig. 112. — Open top extractors. SEWERAGE AND DRAINAGE. 189 series of thin wires across to exclude birds, illustrate the best form of extractor for soil-pipes, in the writer's opinion ; it was designed by him, as he could see no reason for obstructing the upward movement of the column of air by placing a cover across it — a plain open pipe will act better. In addition to the unobstructed tube, however, we have here a series of chambers which catch whatever breeze is passing, and send it in accelerated force through a narrow slit across the top of the tube, causing a vacuum, and con- sequently an upward current. One kind of extractor may draw stronger in a high wind; another may obstruct less in a calm ; but, as a rule, it will be found that an open pipe with a simple arrangement such as this for deflecting the passing wind upwards, without obstructing the ascent of the column of air in heavy weather and calm, will be all that a plumber need recommend, fixing the extractor well above surrounding objects, free from chance of a return blow-down. Cowls made trumpet-shape, turning with the wind, and depending on the vacuum which can only be produced in strong wind for the upcast extraction, are as irregular and uncertain in action as the wind itself, and they all even- tually become neglected, and then soon stick fast, and are worse than useless. In some houses the inlet and outlet pipes at back and front are carried up above the roof, and are fitted at top on same level with trumpet-shaped mouths pointing north and south or east and west respectively — depending on the direction of the wind, the outlet sometimes becomes the inlet, the upcast becomes the downcast. The fault in con- struction lies in three points : (1) a high wind may directly unsyphon the closet traps; (2) a frosty air blowing down 190 DOMESTIC SANITARY DRAINAGE AND PLUMBING. may freeze the pipe if water is passing ; (3) if the wind be blowing equally across both mouths, or if it be calm, stagnation results and danger arises. The Method of Testing House Pipes and Drains. Long experience is absolutely necessary to give the skill essential for the thorough inspection and testing of drains and sanitary arrangements. Although the author has in- spected more than 3,500 houses, he yet finds fresh difficulties to surmount, and new combinations of faults to detect and remedy. When called to examine the sanitary fittings of a house, first ascertain whether any illness has occurred which may be attributed to defective fittings. If typhoid, then look specially for water pollution and dairy or larder drain defects. If diphtheria or bad sore throat, look for the leakages in drains or pipes of foul air, or entrance of foul air near rooms where illness took place, but be always alert to note every- thing, as the origin of diphtheria infection is still obscure. Proceed to the roof and take note of the rain down pipes, and of any vent-pipes or the absence of them ; then go rapidly through the rooms, floor after floor, noting in your mind the kind of fittings and their position, remembering them as well as you can. Finish at the basement and front and back areas. Now make an accurate plan of the basement to, say, one-quarter or one-eighth inch scale in your book. This is the most important part of any sanitary inspection or test. Without a plan you cannot bear in mind the position or arrangement of drains or fittings for one week, especially if you have two or three houses to inspect daily. That done, proceed to test the drains. Make an opening at the rear of drain, and cut across the drain in front ; close it watertight with one of the indiarubber bags used by gas companies, as shown in Fig. 113, <Callout type="important" title="Proper Testing">Use indiarubber bags for a watertight seal when testing drains.</Callout> Fig. 113. or, better still, with an expanding drain stopper in which indiarubber ring is expanded by screw pressure. Fig. 114. — Drain plug or stopper for use in testing drains and pipes during hydraulic and smoke tests. Fig. 115. — Jones' Patent Expanding Screw Stopper. These stoppers are made in brass and iron to suit drains from 4 in. to 24 in. diameter; they are easily applied and are most effectual. Be careful to fix the drain stopper in such a position that you can easily see that it keeps staunch during the period of your test. You then proceed to the rear of the building and fill the drain with water. You must, of course, stop up any low-level openings, to prevent escape of water. Watch the water-level in rear, &tv9nM iJtrtAtsa Fig. 115. — Drain stopper. Fio. 116. — Drain stopper. ^KDRicAL AiE Bag StqppO Bag Inflated '^InQcANVAS COVER Flo. 118. — Drain stopper. 6''UK)iE CJUnOlB COVER Fio. 117. — Drain stopper. ^''looss canvas c:ver Fio. 119.— Drain stopper. Fig. 121.— Drain stopper air pump. EXElUfDlMS Fio. 120. — Drain stopper. BRASS AIR PUMP Fig. 122. SEWERAGE AND DRAINAGE. 193 and if it does not sink the drain is staunch ; if it does sink, endeavour to discover where it is escaping, and see whether any is running away along the outside of the drain and appearing where drain is open in front. Carefully distinguish between the water escaping from the drain, leaking round the bag, and the water escaping from joints of drain behind and escaping outside the drain. Having noted all this, and the time water stood in the drain, fill it up as full as possible and suddenly withdraw the bag, and watch the speed of the water flowing out, and note what amount of filth or deposit is carried away by the rush, to determine whether the drain held the soil in deposit or not. To enable you to tell approximately how many gallons of water should fill any drain, note that a 4-inch drain contains half a gallon, a 6-inch drain contains one and a quarter gallon, and a 9-inch drain contains two gallons and three-quarters per lineal foot. Therefore a 6-inch drain, fifty feet long, will take about sixty-two gallons to fill it, while a 9-inch drain, same length, will take one hundred and thirty-seven gallons to fill it. Note the velocity of flow through the drain, and thus ascertain the gradient. Proceed now to test the soil-pipes and connections by the smoke test. Take any apparatus that will blow smoke into the drain, and, using brown-paper or oiled tow fuel, or the specially prepared sinoke-rocket, force the smoke into the drain, shutting all doors and windows at front of house when you apply the test at the same place where you have already cut the drain. There is one smoke-producing and forcing arrangement with a revolving blower like Clark's bellows, another with a pumping bellows action, and yet another plan of testing by a squib or rocket, which bums for five to ten minutes in the drain. All the connections, traps, and joints should be care- fully watched through house, and smoke escapes noted down. 0 194 DOMESTIC SANITARY DRAINAGE AND PLUMBING. Fio. 123. — ^The aspliyxiator, for applying smoke test to drains. Fig. 124. — Smoke generator for testing drains. Fig. 125. — Smoke generator for testing drains. The peppermint test is applied by taking a small bottle of oil of peppermint and a can of boiling water out on the roof and pouring them down the vent-shaft of soil-pipe if you can get at it, closing the vent, and having someone in the house to note if any smell of peppermint becomes apparent, and where it comes from. The test requires delicate handling and is troublesome; the person applying it will have to remain some time on the roof, for if he comes into the house he brings the odour of peppermint with him, which spoils the test. The hydraulic and smoke tests will be sufficient as a rule. The sulphur test is powerful and searching. Take one pound of flour of sulphur, and pour half an ounce of methylated spirits over it; set it in an iron plate in the drain, set it on fire, and cover it up, and the fumes will show any defects in the house very plainly; but the house should be empty, as these fumes escaping are very irritating. Proceed to examine the surface traps, troughs, sinks, closets, cisterns, and their overflows ; specify in your notes the arrangements of each in detail for waste-pipes, over- flow, trapping, and state where water supply is drawn from. Fill each with water, and discharge again to see if waste is clear, if trap imseals, or if any other traps are affected in the other appliances by the discharge. Note the rain-pipe connections and air-vent pipes, and their terminals above and below. If necessary, pass drain -cleansing machine through drains and branches, and observe condition of interior thus revealed. Note the waste-pipes from safe-trays, and see if they discharge safely in open air. In fact, note everything up and down, that can possibly affect the sanitary condition of the house and the health of the residents, and remember, when you are asked to inspect and give your opinion as practical men on the sanitary condition of a dwelling-house, that a great and clear drains. Fig. 128. — Double spiral screw to Fio. 129. — Archimedean screw to extract cloths, etc. solemn trust and responsibility is laid upon you, and that the lives of the future residents may depend upon the care, skill, and thoroughness which you devote to the execution of your duty, and that one careful and thoroughly practical report will show that you know your business and are willing to do it well, and will do more to prove that you are practical men, and proper persons to make sanitary inspections of houses, than all the letters written to all the newspapers in the kingdom. A list of fifty-one specific insanitary and dangerous defects actually discovered during sanitary inspections in dwelling-houses may prove a serviceable indicator. SEWERAGE AND DRAINAGE. 197 1. Common brick or stone-built drains under basements. 2. Large, built drains under or near dwellings. 3. Pipe drains of lai^er diameter than actually necessary. 4. Pipe drains broken, or with leaking joints, saturating the subsoil with sewage. 5. Pipe drains with built or imperfect junctions. 6. Pipe drains under dwelling without sufficient fall. 7. Pipe drains with fall in the wrong direction. 8. Drains of any kind without proper intercepting traps. 9. Drains of any kind without constant free current of air throughout. 10. Drains without easy means of inspection. 11. Drains carried from public sewer direct under hall- door steps and under scullery floor instead of across open area. 12. Eat burrows from built drains undermining floors. 13. Rat burrows from public sewer worked along outside pipe drains into houses. 14 Defective connection between soil-pipes and drain. 15. Soil-pipes inside houses under almost any circum- stances. 16. Soil-pipes inside or outside without any or ample ventilation. 17. Soil-pipes through pantries, larders, or stores. 18. Defective, badly placed, or ill-constructed water-closet apparatus and housemaids' slop-sinks. 19. Water-closet cisterns with overflows joined to soil- pipes or drains. 20. Safe-trays under water-closet joined to soil-pipes or drains. 21. Two or more water-closets or sinks on one soil-pipe, untrapping each other when used. 22. Overflow-pipes connected to soil-pipes liable to become untrapped, all very dangerous. 198 DOMESTIC SANITARY DRAINAGE AND PLUMBING. 23. Water supplies over troughs taken from water-closet or other contaminated cisterns, and liable to be used by careless servants to fill bedroom carafes for drinking. 24 Taps for supplying bedroom water fixed over house- maids' slop-sinks, liable to be polluted by splash from slops emptying. 25. House cisterns, with overflows, joined to soil-pipes or drain. 26. Traps of every kind, without ample ventilation to guard them. 27. Scullery sinks connected direct to drains, admitting foul air, not only through traps, but through joints of brick- work and plaster all round. 28. Bell traps, with loose covers on scullery sinks. 29. Gullies or traps in floors of sculleries, laundries, larders, or basement, etc., connected to drain, and usually dry and untrapped, or full of foul deposit. 30. Ventilating foul-air shafts, discharging near chimneys, or windows, or ventilating openings. 31. Eain-pipes used as ventilators for drains, discharging foul air near bedroom windows, or under roof eaves. 32. Eain-pipes used as or connected to soil-pipes, likely to freeze soil-pipe solid in severe winter. 33. Eain-pipes passing down centre of houses connected in any way to drains. 34. Open rain courses from valley gutters, passing imder floors to outside down pipes connected to drain. 35. Eain-pipes of low roofs, bow windows, or porches connected direct into drain. 36. Ashpits located near larder, pantry, or dwelling. 37. Ashpits liable to let moisture soak into house. 38. Ashpits capable of retaining moisture, or un ventilated. 39. Eat burrows from defective drains in neighbouring premises. SEWERAGE AND DRAINAGE. 199 40. Defective drainage or fittings in neighbouring premises. 41. Any direct communication with drains of neigh- bouring premises. 42. Water tanks in areas, near ashpits or sculleries, or with any connection of overflow to drain. 43. Bath waste or overflow pipes connected to soil-pipes or drains. 44. Washhand-basin wastes or overflows connected to soil-pipes or drains. 45. Water-closet cisterns under bedroom or parlour floors. 46. Cesspools near houses, or unventilated anywhere. 47. Cesspools or drains near wells. 48. Drains crossing your house from neighbours' premises. 49. Field or surface-water drains, with open joints, under basement connected
Key Takeaways
- Position air inlets low and shaded to ensure effective ventilation.
- Use indiarubber bags for a watertight seal when testing drains.
- Avoid using complicated cowls that require constant attention.
- Inspect all drainage systems thoroughly, noting any defects or potential issues.
- Ensure proper ventilation of soil-pipes to prevent stagnation and danger.
Practical Tips
- Position air inlets low on the north side of your house to take advantage of cooler temperatures, which can help reduce odors and improve airflow.
- Use simple, unobstructed vent pipes for soil-drains as they are less likely to become blocked or obstructed by wind changes.
- Regularly inspect and test your drainage systems to ensure they remain effective and free from blockages.
Warnings & Risks
- Complicated cowls can be easily neglected and may stop working, leading to poor ventilation and potential health hazards.
- Using improperly sealed testing methods can lead to false readings and ineffective maintenance of your drainage system.
- Failing to properly ventilate soil-pipes can result in the buildup of harmful gases and create a risk for residents.
Modern Application
While many of the specific techniques described in this chapter are outdated, the principles of proper ventilation and thorough inspection remain crucial. Modern plumbers still use similar methods but with improved materials and technology. Understanding these basics can help ensure that your home's drainage systems function safely and effectively, even during emergencies.
Frequently Asked Questions
Q: What is the best way to position air inlets for effective ventilation?
Air inlets should be positioned low on the north side of the house, shaded from sunshine. This helps ensure that cooler, lighter air can enter while heavier, warmer air exits through higher vents.
Q: Why are complicated cowls less desirable than simple vent pipes?
Complicated cowls require constant attention and maintenance, which is impractical for most homeowners. Simple, unobstructed vent pipes are more reliable and less likely to become blocked by wind changes.
Q: How can I test my drainage system effectively without causing false readings?
Use indiarubber bags or expanding drain stoppers for a watertight seal when testing your drains. This ensures accurate results and helps identify any leaks or blockages in the system.