Field Testing:
Floor Slab F-Number Determinations performed using a FACE CO 2272 Digital Floor Profiler.

By Far The Best Accuracy
Testing labs, building owners, developers, contractors, universities, research institutions and government agenices on six continents choose the Dipstick because it producecs the most accurate and repeatable flatness/levelness data.

Questions About F-Numbers

What are F-Numbers?
The F-Number System is the American Concrete Institute (ACI117) and Canadian Standard Association (CSA A23.1) standard for the specification and measurement of concrete floor flatness and levelness. F-Number replaces the familiar “1/8 inch in ten feet” type specs that had proven unreliable, unmeasureable and unrealistic.

The new standards include two F-Numbers: FF for flatness and FL for levelness

Flatness relates to the bumpiness of the floor, while levelness describes the local tilt or pitch of the slab. The higher the F-Number, the bettr the characteristic of the floor. F-Numbers are linear, so an FF 20 is twice as flat as an FF 10, but only as half as flat as an FF 40.

The ACI/CSA F-Number System applies to 99% of all floor slabs – all floors that support random traffic be it vehicular or pedestrian traffic.

What F-Numbers equals 1/8″ in 10′?
There is no F-number equivalent to any straightedge spec. But, rough equivalents, in terms of horizontal envelopes, can be given.

An FF 25 is roughly equivalent to a single 1/4″ defect in 10′.

An FF 50 is roughly equivalent to a single 1/8′ defect in 10′.

An FF 100 is roughly equivalent to a single 1/16″ defect in 10′.