1.1 This specification covers the manufacture and purchase requirements of products used for the assembly and construction of circular vertical precast reinforced concrete manholes and structures used in sewer, drainage, and water works. 1.2 Part I, Sections 1 – 11, of this specification presents general requirements and requirements which are common to each precast concrete product covered by this specification. 1.3 Part II of this specification presents specific requirements for each manhole product in the following sections:   Product Section     Grade Rings 12     Flat Slab Tops 13     Risers and Conical Tops 14     Base Sections 15     Steps and Ladders 16   Note 1: Future products will be included in Part II in a future revision of this specification. 1.4 This specification is the SI companion to C478. Note 2: This specification is a manufacturing and purchase specification only, and does not include requirements for backfill, or the relationship between field load conditions and the strength requirements of the manhole products and appurtenances. Experience has shown, however, that the successful performance of this product depends upon the proper selection of the product strength, type of foundation and backfill, and care in the field installation of the manhole products and connecting pipes. The owner of the project for which these products are specified herein is cautioned to require inspection at the construction site. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.6 This international standard was developed in accordance