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. Part I@ Sections 1 through 11@ of this specification presents general requirements and requirements that are common to each precast concrete product covered by this specification. Part II of this specification presents specific requirements for each manhole product in the following sections: Note 1??Future products will be included in Part II in a future revision of this specification. This specification is applicable for orders in either SI units (M 199M) or in inch-pound units (M 199). SI units and inch-pound units are not necessarily equivalent. Inch-pound units are shown in brackets in the text for clarity@ but they are the applicable values when the material is ordered to M 199. 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.