A new test method employs a traditional walking-type profiler, which has made it possible for any local lab to test F-min quickly and competently, and at a lower cost.
Allen Face A new test method employs a traditional walking-type profiler, which has made it possible for any local lab to test F-min quickly and competently, and at a lower cost.

The first narrow-strip superflat concrete floor was installed in 1976 by Armando (Sil) Silvestri, of Duron Ontario Ltd., Mississauga, Ontario, Canada, in a new 60,000-square-foot high-bay warehouse being built at the Bruce Nuclear Generating Station on Lake Huron. As soon as each new strip was finished, Sam Face would erect level taut wires next to the future turret truck wheel tracks and measure their profiles using the original profileograph. The resulting paper “EKG” tapes were then couriered back to me in Norfolk to analyze on a light table.

Sil and Sam, destined to become lifelong friends, had decided strip pouring would be the best approach. Installing one strip per aisle and centering the lateral construction joints in the flue spaces (that is, where the racks back up to one another) created a symmetrical arrangement that would put the wheel tracks furthest from the joints and eliminate the future effects of curling.

Prior to placement, the two men gathered the crew to emphasize the goal of making the floor as flat as possible. After making their pleas, with Gino Lisi and Tony Coletti looking on, Nick Tomasone, Duron’s lead finisher, reassured: “Don ‘a you a’worry boss. Weer ‘a gonna make it a’ sooperflat!” And thus was the term superflat added to the flooring lexicon.

Using my feedback and informed trial and error, it took Sam, Sil, and the Italian crew less than a month to evolve the specially straightened and leveled forms, the repeated manual saw-offs, and the multiple cross-cutting and filling techniques that would henceforth epitomize optimal slab construction. Indeed, within a year, at Carlton Cards in Mississauga, this team would install a slab measuring 242 on the yet-to-be-invented F-min scale.

As the profileograph tapes were analyzed back home, a definite pattern revealed itself. Although the graphs would differ in scale from aisle to aisle, their shapes were proving to be remarkably consistent, suggesting that the new narrow strip construction techniques were producing a limited family of waveforms. Because the object of the whole exercise was to restrict the truck motions induced by the floor, I began to track both the maximum tilts and the maximum rates of change in tilt that would be experienced by vehicles having various wheel configurations. Once the data from a dozen or so projects were plotted, the underlying relationships became clear, and it only remained for me to select the equations that would best fit the curves. In January 1980, The Edward W. Face Co.’s Technical Sheet 801 first formalized the F-min System that—with only minor changes—is still in use today.

Rule No. 15b: The proprietary F-min System limits the side-to-side and front-to-back tilt, angular velocity, and angular acceleration to be experienced by a hard-axle vehicle of known wheel configuration traveling along the intended wheel tracks. The official F-min equations are those set forth at www.allenface.com.

For nearly three decades, the Face Companies (or one of its offshoots) monopolized the F-min testing business. To have the wheel tracks in a new narrow aisle warehouse certified as F-min compliant, an owner had to employ a profileograph-equipped specialty firm to collect data and write a report. In 2005, a new test method employing the traditional walking-type profiler finally was developed that made it possible for any lab to test F-min both quickly and competently. As a consequence, many defined-traffic warehouse projects around the world now are being monitored and certified using this much less expensive measurement technology.

Rule No. 15c:The F-min System may be tested using any apparatus capable of recording the requisite wheel track and wheel base elevation differentials at 12-inch intervals to an accuracy of ±0.005 inch (or better).