What does “DR” designate?
“DR” stand for “dimensional ratio.” The dimensional ratio is the nominal outside diameter of the pipe divided by the wall thickness of the pipe. It is used to determine the pressure rating of the pipe. Since the DR is an indicator of wall thickness, it can also be used to determine the proper interfacial force required to properly fuse a pipe. “SDR” stands for “standard dimensional ratio,” and refers to standardized dimensional ratios as referenced in certain ASTM standards.
