I was wondering if anybody knows where I can download 700mm Flanges for waste water piping. I looked on seek and other sites but I can't find any of that diameter
If you cannot find the diameter you are looking for, I would find a family that is close and modify it to be the size you need.
If you have not already, I would review the Families Guide for Revit MEP, which has instructions for creating content.
Revit MEP Families Guide
