SANITARY SCIENCE. 



721 



versed, as when a large fixture is discharged at 

 the upper part of the soil-pipe, the air that 

 may be forced out at the ground-level through 

 the inlet is not of sufficient foulness to cause 

 annoyance; while, what is very important, 

 should a leak or break occur in the general 

 house system of plumbing, the escaping drain- 

 air would be so diluted by the outer atmosphere 

 as to be rendered comparatively harmless. 



The improvements thus far mentioned had 

 solely in view the exclusion of sewer-gas from 

 the house, and the free ventilation of drains 

 and waste-pipes. A new difficulty remained : 

 the siphonage of traps either by their own 

 discharge or by the pulling action of other 

 fixtures when emptied near by or above them. 

 For example, if a water-closet on an upper 

 floor is discharged, its contents, in passing 

 downward, fill the soil-pipe like the plunger 

 of a pump, at once pushing the air before, 

 and creating a vacuum behind. These two 

 influences are almost certain to unseal traps 

 on any fixture connecting with the soil-pipe 

 at points below, unless they are provided with 

 separate vent-pipes. This precaution is now 

 taken in good practice, and in addition to the 

 open soil pipe extended to the roof, a back 

 air-pipe is carried from the crown or bend of 

 each trap to the outer air. Objection is made 

 by some sanitarians that these back air-pipes 

 are expensive, and are liable to be choked with 

 condensed moisture or grease ; but the general 

 experience is decidedly in favor of their use. 

 Another important benefit is obtained from 

 the separate ventilation of each trap, and that 

 is a thorough circulation of air throughout the 

 drainage system. Without this, dead ends 

 would be formed, which would invite corro- 

 sion of the trap, and thus permit foul air to es- 

 cape into living-rooms. Where there are in- 

 terior water-closets or bath-rooms, it is not 

 expensive to run a small galvanized-iron flue 

 from the ceiling through to the roof of the 

 house, and supply a heated current within it 

 by means of a light kept constantly burning. 

 Such a device will not only ventilate the 

 closet itself, but contribute toward drawing 

 foul air from the adjoining rooms. 



These four provisions ventilating the soil- 

 pipe, trapping each fixture independently, trap- 

 ping the main drain from the sewer or cess- 

 pool, and supplying foot ventilation with back 

 air- pipes for each trap as a security against 

 siphonage may be called the essentials of 

 modern plumbing practice. But other and 

 later improvements have been effected, which 

 are set forth in the sanitary codes of New 

 York and Brooklyn. First among these is the 

 employment of extra heavy material, such as 

 cast-iron pipe of double weight, tarred inside 

 and out, or of lead waste-pipes of proportionate 

 thickness and weight, and the avoidance of 

 tile-pipe, unless it can be properly laid under 

 competent supervision. Second, the concen- 

 tration of house-plumbing in a limited area, 

 and as far as possible away from the living 

 VOL. xxiv. 46 A 



portion of the dwelling. Third, the placing of 

 pipes so as to be always open to view or easily 

 accessible, drains being supported along cellar- 

 walls instead of being buried underground, and 

 all casings to other pipes being fastened with 

 screws instead of nails, so as to be readily 

 removed for inspection. Fourth, the insuring 

 that every fixture and drain shall be kept clean 

 by thorough flushing. This necessitates a sep- 

 arate cistern for each water-closet and the 

 preference of small drain-pipes, which will be 

 cleansed by every discharge of the fixtures, 

 rather than large pipes, which are seldom 

 flushed, and hence remain constantly foul. 

 Fifth, the absolute disconnection of refrigera- 

 tor-wastes, tank - overflows, and safe- wastes 

 from the house-drain, so that there is no pos- 

 sibility of their proving sources of contamina- 

 tion. Sixth, the employment of better fixtures, 

 such as water-closets made all in one piece of 

 porcelain, with no joints or complicated valves 

 or other mechanism to get out of order, and 

 baths, sinks, and other fixtures made of similar 

 material. 



Besides the ordinary ventilation of traps and 

 soil-pipes, it is now becoming common to pro- 

 vide special vents to remove foul air from the 

 receivers of water-closets and also from below 

 the seats of such fixtures. It is claimed that 

 the serious drawbacks of pan water-closets are 

 neutralized by the former device; but unless 

 the vent-pipe is large and carried in the vicinity 

 of a heated flue, it will not prove of any prac- 

 tical service. As ordinarily put in, it is worse 

 than useless, as there will be no upward move- 

 ment of air in it, but very often a down draught. 

 This vent-pipe is usually three quarters of an 

 inch in size, and is far too small to serve any 

 purpose. There must be two openings for 

 ventilation, and a fresh-air inlet must be pro- 

 vided. In the Hellyer water-closet a two-inch 

 vent is taken from the receiver, and if carried 

 near a hot flue will prove useful. In the Zane 

 and Demarest closets a vent is taken from the 

 compartment that contains the plunger. The 

 mistake is constantly made of connecting such 

 vents from water-closets and urinals into the 

 air-pipe from the traps of fixtures, thus bring- 

 ing the sewer into direct connection with the 

 house side of the trap, and thus neutralizing 

 the latter safeguard. To ventilate below the 

 seat of a water-closet, an annular pipe of gal- 

 vanized iron is used, as shown by Mr. Phil- 

 brick. This should not connect into the chim- 

 ney, or a down draught may be created, as 

 happened in one case where the occupants of a 

 house sent word to a plumber that the water- 

 closet was smoking. Hoppers are now made 

 with a vent taken from between the bowl and 

 the trap. This is a good arrangement, provid- 

 ed the pipe is heated in any way, so as to 

 promote an upward current. 



In a New York hospital an attempt was 

 made to ventilate the plumbing fixtures into a 

 heated flue by creating a down draught through 

 the soil-pipe, and along the main drain in the 



