Floor Slab Flatness and Levelness

Hassan,

Thank you for the comment. F-numbers were conceived because of the in measuring floor flatness with a straightedge gave inconsistent, and sometimes meaningless, results. No standard existed for taking straightedge measurements. Without a standard, test results could not be duplicated with reasonable certainty.

F-numbers measurements rely on a calibrated machine that measures the difference in elevation between points 12 inches apart as it is pulled across the floor slab in a prescribed pattern. The measurements and pattern were devised so that test results could be repeated within an acceptable standard deviation.

ASTM E1115 and ASTM E1115M describe the method for conducting the tests and the calculations that must be made to determine the F-numbers. The machines developed by Allen Face take the measurements and report the results electronically. The results are analyzed in a Microsoft Excel spreadsheet to determine the final overall and minimum FF and FL numbers.

F-numbers are a proven, reliable method to evaluate the concrete contractor's ability to control the cast-in-place concrete floor surface tolerances. Visit http://allenface.com/ for additional information and some instructional videos about how to perform F-number measurements.