Dimensional Tolerances in Construction and for Surface Accessibility

1.1.6 Flatness of walk cross slope. For walks and other pedestrian paths, measure flatness of the cross slope by placing a 24 - in. (600 mm) digital inclinometer perpendicular to the line of travel at 10 ft (3 m) intervals with not less than two measurements. Measure along two paths, each with the end of the digital inclinometer 1 ft (300 mm) from the edge of the path and placed toward the middle of the path. See Fig. 2. If the path is less than 6 ft (1.8 m) wide the ends of the measurement will overlap at each interval.

This method of measurement is based on the assumption that most accessible exterior walks will be at least 60 in. (1525 mm) wide due to passing requirements and that users will tend to stay toward one side or the other when traveling, approximately 1 ft (300 mm) from the edge. This method will reveal problematic variations in cross slope even though the overall cross slope may meet the 1:48 (2%) limitation.