Dimensional Tolerances in Construction and for Surface Accessibility

1.1.9 Horizontal gaps and vertical alignment. Measure for local horizontal discontinuities and variations in vertical alignment such as at concrete joints, gaps, grade breaks, and at the interface of concrete with other materials or elements built into the surface. Measuring devices should be capable of measuring to a precision of 1/16 in. (1 mm).

Requiring a measuring precision of 1/16 in. (1 mm) allows measurements to be made to the nearest 1/8 in. (3 mm) without interpolation and allows the use of commonly available measuring tapes.