Sch 40 vs. Sch 80 PVC Fittings
Schedule 80 PVC pipe and fittings have a thicker wall size than schedule 40 PVC. For example, the wall thickness of SCH 80 1" pipe is 0.179" while SCH 40 has 0.133". The outer diameter measures the same for both SCH 40 and SCH 80 pipe-- fittings have the same inner diameter.
SCH 80 pipe and fittings are designed to handle higher water pressure than SCH 40.
Most residential sprinkler systems will only require SCH 40 PVC. SCH 80 is used for more commercial and agricultural applications.
Usually SCH 40 is white and SCH 80 is gray... Usually