Appendix A: Verification And Calibration - Triax ASTM F1292 User Manual

APPENDIX A
TRIAX TOUCH VERIFICATION PROCEDURE AND CALIBRATION
A.1 Why use a reference pad?
The measurements made by the Triax Touch are not easy to duplicate using other test equipment.
As such there must be a means for a user to ensure that the instrument is working properly between
factory calibrations. When a Triax Touch is manufactured and tested at the factory and is in a
known good condition, a series of drop tests are performed on a 8 inch (203 mm) square reference
pad. The pad is then supplied with the respective Triax system and whenever the pad is retested
by the user the results should agree, within an established tolerance, with results originally
obtained at the factory.
A.2 Establishing Initial Reference Pad Values
Subsurface conditions (i.e. the hardness and thickness of concrete) will affect the reference pad
values and yield different values than the factory values. To fully utilize the reference pad, initial
reference pad values for a particular subsurface must be obtained.
There are no user accessible means of performing calibration adjustments.
NOTE: The reference pad must be stored at normal room temperature and humidity conditions in
order to provide reliable results. After transport or storage involved extended temperature or
humidity allow the pad to acclimate to normal room condition for at least 12 hours.
A.2.1 Place reference pad on a bare concrete surface (no carpet or tile, painted is fine)
A.2.2 For a Triax Touch E missile erect the tripod and position the missile that the bottom of the
missile is 36" +/- ¼" (915mm +/- 5mm) above the surface of the reference mat.
For a Triax Touch "A" missile system the drop height is 24" +/- ¼", and is measured from the
surface to the center of the release knob.
A.2.3 Perform three drop tests, waiting 1.5 minutes ±30 seconds between drops, averaging the
Peak G and HIC results of the second and third drops. This average Peak G and HIC are the Initial
Reference Pad Averages and should be recorded on the Reference Pad Data Record for future use.
The measured Peak G should agree within +/-10% of the average of the Peak G of drops 8 and 9
on the factory calibration report, ensuring that the system was not damaged during shipment or
storage. The +/-10% window compensates for differences in the concrete floor between the factory
and the user's locations.
If the Initial Reference Pad Averages are not within the specified range contact technical support
before proceeding.
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