We advise recalibration of radiometers every two years. Over a two-year period in the field the sensitivity of an instrument changes slightly. For customers who have a large number of pyranometers and/or albedometers, or who maintain a network of instruments, regular re-calibration in Delft creates down-time and requires logistical effort. The Kipp & Zonen CFR Calibration facility offers the customer the means to perform factory-standard calibrations of pyranometers and albedometers themselves, saving time and money.

The CFR Calibration Facility for Radiometers is designed primarily for the calibration of field pyranometers and albedometers by comparison to a reference pyranometer of similar type under controlled laboratory conditions. The procedure that is described in the CFR manual complies with ISO 9847 "Calibration of Field Pyranometers by Comparison to a Reference Pyranometer", specifically Annex A.3 "Calibration devices using artificial sources - direct beam apparatus".

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 stabilization of the calibration lamp, takes about 30 minutes. The calibration transfer accuracy for higher quality pyranometers, 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, 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.