Thanks for the replies. It looks like we have conflicting opinions, and there seems to be confusion with what's actually available on the market :) To be honest I think it doesn't matter in real life, but I was just trying to understand the different fitting and pipe standards.
I was able to find 3'' SDR-35 ASTM D-2729 pipe, as well as 3'' SDR-35 ASTM D-3034 pipe; but I was not able to find 3'' ASTM D-3034 fittings. The S&D fittings seem to typicalle come with a disclaimer "3'' meets ASTM D2949 or exceeds ASTM D2729; 4'' and 6'' meet ASTM D3034". I understand that ASTM...