Charles O'Grady, Marlboro, Mass., writes: "I send sketch of a plumbing job of two water-closets in a basement, and one sink on the first floor. 1 have back- vented the water-closets into the foot vents. Is there any objection to doing so?"

[Figure 1 shows our correspondent's sketch. The practice of venting fixture traps into the fresh-air inlet (foot vent) is not to be recommended. The fresh-air inlet if open in the sidewalk is liable to become choked, in which case the traps are not protected. Circulation of air through the vent pipes is more liable to take place if the vent pipes are connected with a long upcast pipe to the roof. Discharge from fixtures, as shown in Fig. 1, would tend to cause an out-draft in the foot vent, while the traps would need an in-draft to prevent syphonage and the vent currents would be working against each other. Other faults in your design are: 1 The fresh-air inlet (foot vent) opens too close to the house. 2. The basement closets appear to be in the center of the house. They should have direct light and ventilation through outside windows. 3. The main trap cleanout should be on the house side of the trap If the cleanout cover is not tight and leaks, air from the house drain is preferable to air from the sewer. Figure 2 shows an improvement on your design, with some slight economy in piping. The bottom of the 2-inch pipe A opens directly into the crown of the trap, so that rust, scale, etc. will be washed out by the water-closet discharge. The pipe B should be given a sharp angle so that dirt and rust will run down the pipe. The upcast pipe C should at its upper end be well removed from bedroom windows. Brass cleanouts should be used at the points D D]

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