CAN/CSA-A257.4-M92

1.1 Pertains to precast reinforced circular concrete manhole sections including base sections, riser sections, catch basins, and appurtenances such as grade rings, tops, and special sections for use in sewer and water works. Note: This Standard is applicable to manufacture and purchase only, not installation. 1.2 The requirements of this Standard are applicable to precast concentric cone, eccentric cone, and flat slab type tops. 1.3 The requirements of this Standard are applicable to precast base riser sections with separate base slab, precast base sections with integral floor, and precast base sections with precast benched inverts. Note: Experience has shown that the successful performance of these products depends upon the proper selection of the design of the sections, the type of bedding and backfill, and care taken in the field construction work. The purchaser is cautioned that the field requirements must be properly correlated with the design requirements specified and adequate inspection at the construction site must be provided. 1.4 This Standard does not pertain to cast-in-place work.