Figure 3.—Jointing sewer pipe. A, Using calking iron to force packing into joint. B, Making joint with 1:2 portland cement mortar. Use only enough water to dampen the mix. Recalk after half an hour, to close shrinkage cracks. C, The completed joint. Wrap finished joint with cloth and keep dampened, to aid curing. D, Joint made by pouring 1:1 Portland cement grout of creamy consistency into a form. This type of joint is not feasible unless the metal forms shown are available. E, Use of asbestos runner clamped around pipe, for pouring hot joint. F, Clay roll used in place of asbestos runner. G, A completed bituminous joint. H, Use of swab, to remove any joint material forced through to inside of pipe.
Soft pig lead or old scrap lead is suitable for lead joints on cast-iron pipe. About 3/4 pound per inch of pipe diameter is generally required for each joint. The lead is hot enough to pour when it begins to char the paddle used to skim off the impurities. When it cools it must be calked tightly to take up shrinkage. The calking should be uniform around the entire joint and should stop when the lead is tight. Heavy pounding or continued calking may crack the bell of the pipe.
It is easier to get good, joints when the pipe is in a vertical position. Therefore, two lengths of pipe are frequently joined and are then laid as a single unit in the trench. In using terra cotta pipe, this procedure may be followed only when the joint is made with a mastic compound. Cement-mortar joints cannot be used in such cases.
Before filling the trench, the sewer should be tested to detect possible leaks. Earth free from rubbish and large stones should then be tamped around and about 1 foot above the pipe.
Flow Through the Tank