Out-of-roundness of the pipe, calculated as follows: (Dmax – Dmin) / (Dmax + Dmin), where Dmax and Dmin are maximum and minimum pipe outside diameter, respectively.
Source: API RP 17B, Recommended Practice for Flexible Pipe, Fourth Edition, July 2008. Global Standards
Deviation of the circumference from a circle which has the form of an elliptic cross section.
Source: API Standard 2RD, Dynamic Risers for Floating Production Systems, Second Edition, September 2013. Global Standards
Source: API RP 17G, Recommended Practice for Completion/Workover Risers, Second Edition, July 2006 (Reaffirmed April 2011). Global Standards