Summary
Highlights
Trenches must be backfilled with thin layers of clean earth above the pipes, free from stones, boulders, cinders, or other materials that could damage pipes or cause corrosion.
Vitrified clay pipes are typically used, but galvanized rod iron or galvanized steel pipe should not be used underground and must be kept at least 152 mm above ground. Copper tubing (Type M) can be used above ground inside or on top of buildings, or underground with a protective coating.
All wet vented fixtures must be on the same floor level. Private sewage disposal systems for establishments like slaughterhouses must connect to and drain into an approved grease interceptor for proper effluent disposal, discharging through a screening device.
Drains should have a total net inlet area not less than twice the area of the outlet pipe to which they are connected. Vertical piping can be round, square, or rectangular. Lead pipes should be supported at intervals not exceeding 1.2 meters at centers with rigid vertical backup. Plastic pipes, when installed vertically, require support every 4 feet.
The bottom of pipe trenches deeper than the footing of an adjacent building and parallel to it must be at least 45 degrees away from the footing. The maximum trap loading for a 2-inch pipe is four fixture units. For a trap with six fixture units, the maximum loading corresponds to a 76 mm pipe.