The size, slope, alignment, materials of construction of a building sewer and the methods to be used in excavating, placing the pipe, jointing, testing and backfilling the trench shall conform to the requirements of the building and plumbing codes or other applicable rules and regulations of the city. In the absence of code provisions or in amplification thereof, the materials and procedures set forth in appropriate specifications of the American Society for Testing and Materials (ASTM) and Water Environment Federation (WEF) Manual of Practice No. 9 shall apply.