Product Manual

8
In the case of Impact Control, there are no hard and fast rules because the results are dependent on soil type, organic matter,
moisture content, and the influence of the turf grass and its root zone. It is recommended to run a few experiments to
determine the protocol that works best for your application or use your experience which may well be the best predictor of
what range of impact values provide the desired results. Moisture Sensing is also critical on natural grass fields to pair with
the Clegg readings for more meaningful results.
To determine a custom protocol, the initial step would be to collect or use historical data (Clegg impact values) on surfaces
you want to monitor. Take experimental data when the surface is in a desired condition and an unacceptable condition.
With this data you can:
• Select an acceptable range of impact values for the surface
• Track the change in impact values as maintenance or modifications are made to the surface
NOTE: Field test data has shown a correlation between gMax F355 test and Clegg impact values. If testing is performed
with the App Settings in “Gmax” and “Peak” as described on page # 12 of this instruction manual, you do not need to use
the regression equation as shown on page 17.
TESTING PROCEDURE
Once the desired protocol has been chosen and set up in the Clegg Control app, follow this procedure to complete the
testing process.
1. For standard sports turf testing of natural grass fields synthetic turf fields, be sure that Display: PEAK is selected in the
Clegg Control app settings.
2. Enter or select the appropriate drop site in the Clegg Control app. For more information about setting a drop site, read
the Drop site on page 13.
3. Ensure that the cable between the control unit and hammer is properly connected. For more information, read Control:
Hammer Connection on page 5.
4. Ensure that the striking face of the hammer is free of foreign material and the inside of the guide tube is reasonably
clean so that the hammer is able to fall freely.
5. Locate then select the appropriate drop location in the Clegg Control app and clear any loose surface material or foreign
objects from the test spot that could produce a result not indicative of the material being tested.
6. Place device vertically in position and hold down guide tube with a foot on the base flange. Brace guide tube with leg
and/or knee (if necessary) to hold tube steady and as close to vertical as possible using the level provided by Turf-Tec
International.
7. For Impact Control
Raise the hammer to white line and drop. This single drop represents the standard impact test protocol. Depending on
the surfaces/materials being tested, a custom protocol may be used.
8. Move to next drop location and repeat steps 3 through 7.
NOTE: When using the Clegg, the Plunger Release can be used to provide consistent drop distance. Read Hammer Drop
Procedures on page 6 for more details on using the Hammer Release Spring Plunger.
STANDARD DROP HEIGHT
Raise the hammer until the white line on hammer is even with the top of the guide tube. Drops should be made with the
line within + 1.25 cm (1/2 inch) from the top of the guide tube.