Dimensional Tolerances in Construction and for Surface Accessibility

1.1.16 Alternate measurement tools. Ramps may be measured with instruments other than a digital inclinometer if they provide the data required for evaluation of tolerances as given in Sections 1.2.5, 1.2.6, and 1.2.7. If the F - number system is used ramps should have a minimum FF of 25. Measure running slope along the same lines of measurements as stated in Section 1.1.13

Although the F - number system can be used to measure surface flatness for smooth surfaces it requires expensive equipment and workers trained to do the measurement.

An FF of 25 provides for a flatness of approximately ¼ in. in 10 ft (6 mm in 3050 mm). Waviness index may be a more appropriate measure to include if floor profilers are used. The waviness index method is described in ASTM E 1486, Standard Test Method for Determining Floor Tolerances Using Waviness, Wheel Path and Levelness Criteria.