Under the HSDPT Alliance, calibration is standardized internationally, and the following criteria must be met:

1. All gauges are calibrated in accordance with the requirements of ASTM D4945 or ISO 9000.
2. Calibration of all gauges is available to Alliance members, that includes full details of the calibration, including the name of the calibration facility.
3. Calibration by the manufacturer or an independent and registered calibration laboratory is preferred to in-house calibration. Link to calibration database