Definitions for "Ovality"
There are two options: a) the difference between the maximum and mean diameter divided by the mean diameter, and b) the difference of the mean and minimum divided by the mean, at any one cross section of a pipe, generally expressed as a percentage.
The difference between the largest and smallest outside diameter on a cross-section.
Deviation from a circular periphery, usually expressed as the total difference found at any one cross section between the individual maximum and minimum diameters, which usually occur at or about 90 degrees to each other. Since ovality is the difference between extreme diameters, it is not expressed as plus or minus.
A quantitative measurement of how "round" a tube is, which is derived by comparing width to height. Limits of ovality are specified on the appropriate ASTM specification of a product.