PVC Venting

Hey Guys,

Typically we see Type B double-wall vent pipe on gas furnaces. Today I ran into one that is using PVC for vent pipe. Is this something that I should call out? Everything else on this systems looks top notch.

Thanks !

High efficiency furnace, by the time the exhaust gases leave the furnace, they are cooled down considerably and do not require a type B vent.

Thanks !