Sewer pipes in yards shall be of the best quality vitrified pipes or concrete sewer pipes with cemented joints composed of one part of portland cement and two parts of clean sharp sand, well worked into the bells and smoothed with a bevel away from the joints. The inside of the pipe shall be carefully swabbed to prevent projection into the pipe of loose materials or of mortar, provided that where, in the judgment of the inspector, gaskets are necessary to make a first-class job, the gaskets shall be inserted. Sewer pipes shall not be laid nearer to any exterior wall of a building than two feet, shall be at least one foot below the surface of the ground at the exterior of the building, and shall be laid with as little change in direction as possible. If a change in direction is necessary, the change shall be made with suitable fittings or by deflections in the pipe not exceeding two inches per two-foot lengths of pipe. Pipe sewers shall have a fall of not less than one-quarter inch per foot, except when local conditions prevent compliance, or when a lesser fall may be approved by the City Engineer. No vitrified pipes shall be laid in bad or made ground. Instead, in such cases, sewers beneath the ground shall be of cast iron pipes.
(Prior Code, § 4.430)