Kritech & Co PGmbH

CFR offers a solution for quality control of the stability of the pyranometers that are used in a network. The procedure used complies with Annex A.3 of international standard ISO 9847 "Calibration of Field Pyranometers by Comparison to a Reference Pyranometer". Annex A.3 refers to "Calibration Devices Using Artificial Sources".

The facility is manually operated and the time needed for each calibration is approximately 10 minutes. Preparation for a measurement session including warm-up and stabilisation of the calibration lamp will take about 30 minutes. The calibration transfer uncertaintyy between reference and test pyranometers of high quality, such as the CMP 11, is estimated to be ± 1%.

The turntable supplied with the CFR is suitable for calibration of CM 6, 11, 21, 22, 31 and CMP 3, 6, 10, 11, 21, 22 pyranometers. Adaptors and alternative turntables are available to suit other pyranometers and albedometers. CFR is supplied without reference pyranometers. These should be purchased separately and be of similar characteristics to the field radiometers under test.

To ensure that calibrations are carried out to Kipp & Zonen, WMO and ISO quality standards, special requirements apply for the calibration facility and technicians performing calibrations. Appropriate reference radiometers for the calibrations must be available or purchased, and the calibration of these reference instruments must be traceable to one of the world standards. The calibration room must be secure, temperature controlled, with non-reflecting walls and a stable AC power supply. Technicians responsible for calibrations must have in depth knowledge of all the aspects of calibrations.

For the above reasons Kipp & Zonen only supplies calibration facilities in combination with installation and technician training by a Kipp & Zonen specialist. Technicians will receive certificates from Kipp & Zonen stating that they have passed the training to carry out calibrations for specific instrument types to the required standards.  Usually, the supply of a calibration facility includes a return visit after 2 years by a Kipp & Zonen specialist; to ensure that the correct operations and procedures are being maintained and that the reference radiometers and measurement electronics have valid calibration certificates.