Question: are pvc and cpvc fittings interchangeable?
Answer: All major brand PVC pipe is made to NPS (Nominal Pipe Size) standards, or “schedules.” Schedule 40 and 80 are the most common NPS schedules. ... 80 PVC and sch. 80 CPVC will fit together because they have the same ID and OD. The same is true of schedule 40 PVC and CPVC, but that type of CPVC is rarely used.