Why Everyone Should Look At Their Daily ASTM E11555 FF/FL Graphs
by Loral Concrete Slab Solutions
One of my clients has a finishing crew that consistently produces very high FF/FL numbers — often exceeding the specified Overall Values.
Then suddenly… the numbers collapsed.
Same crew.
Same process.
Same project.
The floor reportedly failed the OA FF specification.
So what happened?
Did the crew suddenly forget how to finish concrete for 3 days out of 12?
Probably not.
Before anyone starts grinding concrete, assigning blame, or questioning the placement crew…
LOOK AT THE GRAPHS.
The graph patterns can tell you almost immediately whether you’re dealing with:
- A screeding problem
- A finishing problem
- A mixture problem
- Or invalid testing data caused by a profiler zero issue
One of the most common problems I see with Dipstick® floor profilers is improper zeroing.
The result of a Zeroing Issue are jagged “Saw Tooth” graph patterns with unrealistic elevation swings across the runs.
In one example, WE1, a 150-foot test run, appeared to move up and down ½” every 10 feet while simultaneously reading nearly 1/2″ higher than adjacent floor areas.
That’s not a finishing issue.
That’s invalid data.
When zeroing errors occur:
- A screeding problem
- A finishing problem
- A mixture problem
- Or invalid testing data caused by a profiler zero issue
In this case, I forwarded the suspicious data collected from the DipStick to the manufacturer for review.
Their response:
“These runs show the up-and-down pattern typical of a Dipstick unit that was not properly zeroed or started with an unstable zero.”
Their recommendation:
Recollect the data after carefully zeroing the unit and confirming stability before testing.
Problem solved. No grinding required.
I once experienced similar issues with self-zeroing D-Meters®.
On one 800,000 SF warehouse evaluation, every graph I downloaded exhibited a severe slope across the run. The data was unusable.
Since then, I always review the FIRST graph collected before continuing testing.
The takeaway:
Before you grind floors, dispute responsibility,
LOOK AT THE GRAPHS.
Graph review can quickly reveal:
- Testing mistakes
- Elevation control issues
- Screed problems
- Invalid floor profiling data
Sometimes the Finisher isn’t the problem.
The data is.
— Albert Frankeny
Loral Concrete Slab Solutions
