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: an IPS Schedule 40 series, a PS series with an iron pipe size outside diameter with varying wall thickness as required for pipe stiffness of 25, 50, and 100, and a sewer and drain series.