Measurement results are only comparable if they are determined with calibrated and therefore traceable measuring instruments. In addition, the related uncertainty of measurement of the measured value must be specified. The standard defines a procedure for the calibration of clamp-on probes. Described are the steps for the calibration, of the preparation, the implementation up to the documentation of the calibration results. The described procedures define the minimum requirements for the calibration. Required standards for the calibration and measurement procedures for determining the variations in measurements are designated. In addition, instructions for determining the associated uncertainty of measurement are given.