1.1 This specification covers concrete drain tile with internal diameters from 4 to 36 in. that are intended to be used for surface and subsurface drainage.1.2 A complete metric companion to Specification C 412 has been developed—C 412M; therefore, no metric equivalents are presented in this specification. Note 1—This specification is a manufacturing and purchase specification only and does not include requirements for bedding, backfill, or the relationship between field