1.1 This specification covers coextruded poly(vinyl chloride) (PVC) plastic pipe with a cellular core and concentric inner and outer solid layers, and is produced using a multilayer coextrusion die for nonpressure use in three series: a This specification covers coextruded poly(vinyl chloride) plastic pipe with a cellular core and concentric inner and outer solid layers. The pipe is produced using a multilayer coextrusion die for nonpressure use in three series: an IPS Schedule 40 ser