Product Manual

17
Formula converting Gmax from Clegg to F355 units
***Note*** The reading should be the first drop of the hammer, not the highest
reading after 4 drops as described in the ASTM F355 instructions.
Also if App Settings are in “Gmax” and “Peak”as described on page # 12 of this
instruction manual, you do not need to use the below regression equation. Only use
this equasion if your App Settings are in “G” and “Peak”.
Clegg Impact Soil Tester using the regression equation
(F355 × 0.81) - 27.1 = Clegg Impact Soil Tester Value
"The regression coefficient for this equation was 0.95 and indicates that the Clegg
Impact Soil Tester would be a suitable device to measure the surface hardness of
artificial and natural grass playing fields."
The inverse equation is as follows:
(Clegg Impact Soil Tester Value + 27.1) / 0.81 = F355
*Required reading:
"Surface Hardness (Gmax)"
By: Andrew S. McNitt, Thomas Serensits and Dianne M. Petrukak
The Pennsylvania State University
http://cropsoil.psu.edu/ssrc/research/infill/surface-hardness-gmax
Also:
http://cropsoil.psu.edu/ssrc/sportsturf-scoop/gmax
Video Showing uses of Clegg:
http://www.youtube.com/watch?v=4cCq1O8TNmI