1.1 ,This specification covers coextruded poly(vinyl chloride) (PVC) plastic drain, waste and vent pipe made to Schedule 40 iron pipe sizes (IPS) and produced by the coextrusion process with concentric inner and outer solid PVC layers and the core consisting of closed-cell cellular PVC. Plastic which does not meet the material requirements specified in Section 5 is excluded from single layer and all coextruded layers.