1.1. Cross-sectional and Straightness Tolerances
Permissible variations for structural shapes and plates as received from the mill are established in ASTM A6/A6M-04b Section 12. These historically developed standard tolerances define the acceptable limits of variation from theoretical dimension for the cross-sectional area, flatness, straightness, camber, and sweep for rolled sections. It should be noted that cross-sectional tolerances are expressed as a percentage of weight or area, not as tolerances on dimensions such as the flange and web thicknesses.
Generally, standard fabrication practice accommodates these structurally acceptable variations. In special cases such as high-rise construction, the accumulation of mill tolerances may require consideration in design by the Structural Engineer of Record [SER]. If more restrictive tolerances are required they must be specified in the contract documents..
last modified 01 January 2006