For RHS subject to biaxial bending the class is taken as the worst class that results from independent bending about each axis. For biaxial loading all sides will be considered as both web and flange to determine worst class. Limits will be from Table 12. Built-up RHS are assumed to be symmetric when calculating the section classification per Table 12. Unsymmetrical RHS will result in incorrect section classification.

According to 4.8.1 Circular Hollow Sections (CHS) should be classified separately for bending and axial load. RAM Frame and RAM Steel Column only calculate one classification for the section that is the most conservative of the classifications for bending (when it exists) and that for axial load (when it exists) calculated independently.