16. No brick, sheet-metal, earthenware, or chimney-flue shall be used as a sewer-ventilator, nor to ventilate any trap, drain, soil, or waste pipe.

17. Every vertical soil-pipe and waste-pipe must be of iron, and where it receives the discharge of fixtures on two or more floors it must be extended at least two feet above the highest part of the roof or coping, of undiminished size, with a return-bend or cowl. It must not open near a window, nor an air-shaft which ventilates living-rooms.

18. Soil, waste, and vent pipes in an extension must be extended above the roof of the main building, when otherwise they would open within twenty feet of the windows of the main house or the adjoining house.

19. Horizontal soil and waste pipes are prohibited.

20. The minimum diameter of soil-pipe permitted is four inches. A vertical waste-pipe, into which a line of kitchen-sinks discharge, must be at least two inches in diameter with one inch and a half branches.

21. Where lead-pipe is used to connect fixtures with vertical soil or waste pipes, or to connect traps with vertical vent-pipes, it must not be lighter than D pipe.

22. There shall be no traps on vertical soil-pipes or vertical waste-pipes.

23. All iron pipes must be sound, free from holes, and of a uniform thickness of not less than one-eighth of an inch for a diametor of two, three, or four inches, or five-thirty-seconds of an inch for a diameter of five or six inches, and in case the building is over sixty-five feet in height above the curb the use of what is known as extra heavy pipe and corresponding fittings are required, which weigh as follows:

24. Before they are connected they must be thoroughly coated inside and outside with coal-tar pitch, applied hot, or some other equivalent substance.

25. When required by the inspector from the Board of Health, the plumbing must be tested with the peppermint or the water test by the plumber, in the presence of the inspector, and all defective joints made tight, and other openings made impermeable to gases. Defective pipe discovered must be removed and replaced by sound pipe.

26. All joints in the iron drain-pipes, soil-pipes, and waste-pipes must be so calked with oakum and lead, or with cement made of iron filings and sal-ammoniac, as to make them impermeable to gas.

27. All connections of lead with iron pipes must be made with a brass sleeve or ferrule, of the same size as the lead pipe, put in the hub of the branch of the iron pipe and calked in with lead. The lead pipe must be attached to the ferrule by a wiped joint.

28. All connections of lead pipe should be by wiped joints.

29. Every water-closet, urinal, sink, basin, wash-tray, bath, and every tub or set of tubs, must be separately and effectively trapped, except where a sink and wash-tubs immediately adjoin each other, in which case the waste-pipe from the tubs may be connected with the inlet side of the sink-trap; in such a case the tub waste-pipe is not required to be separately trapped.

30. Traps must be placed as near the fixtures as practicable, and in no case shall a trap be more than two feet from the fixture.

31. All exit-pipes must be provided with strong metallic strainers.

32. In no case shall the waste from a bath-tub or other fixture be connected with a water-closet trap.

33. Traps must be protected from syphonage, and the waste-pipe leading from them ventilated, by a special air-pipe, in no case less than two inches in diameter for water-closet traps, and one inch and a half for other traps. Except in private dwellings, the vertical vent-pipes for traps of water-closets in buildings more than four stories in height must be at least three inches in diameter, with two-inch branches to each trap, and for traps of other fixtures not less than two inches in diameter, with branches one and a half inches in diameter, unless the trap is smaller, in which case the diameter of branch vent-pipe must be at least equal to the diameter of the trap. In all cases vertical vent-pipes must be of cast or wrought iron.

34. These pipes must either extend two feet above the highest part of the roof or coping, the extension to be not less than four inches in diameter to avoid obstruction from frost, or they may be branched into a soil-pipe above the inlet from the highest fixture. They may be combined by branching together those which serve several traps. These air-pipes must always have a continuous slope, to avoid collecting water by condensation.

35. Traps of fixtures near the fresh-air inlet may be ventilated by being connected with it.

36. No trap vent-pipe shall be used as a waste or soil pipe.

37. Overflow-pipes from fixtures must, in each case, be connected on the inlet side of the trap.

38. Every safe under a wash-basin, bath, urinal, water-closet or other fixture must be drained by a special pipe not directly connected with any soil-pipe, waste-pipe, drain, or sewer, but discharging into an open sink upon the cellar floor or outside of the house.

39. The waste-pipe from a refrigerator shall not be directly connected with the soil or waste pipe, or with the drain or sewer, or discharge into the soil; it should discharge into an open sink. Such waste-pipes should be so arranged as to admit of frequent flushing, and should be as short as possible, and disconnected from the refrigerator.

40. The sediment-pipe from kitchen-boilers must be connected on the inlet side of the sink-trap.

41. All water-closets within the house must be supplied with water from special tanks or cisterns, the water of which is not used for any other purpose. The closets must never be supplied directly from the Croton supply-pipes. A group of closets may be supplied from one tank. But water-closets on different floors are not permitted to be flushed from one tank.

42. The valves of cisterns must be so fitted and adjusted as to prevent wasting of water, especially where cisterns are supplied from a tank on the roof.