I just did a little research on PVC pipes and found out that they don't give PVC fittings any pressure ratings however, the corresponding pressure rating for pipe is often used as a reference.
PVC is assigned a pressure rating (psi) based on use with water at 73 deg F. As the temperatue rises, the psi drops. The psi drops by 50% at 100 deg F and by 78% at 140 deg F.
While those temps are extreme and since i'm starting from scratch I think I'll play it safe and buy SCH 80. I'm here for the long haul, hopefully, at this house so the extra mony spent is worth it.