Measurement methods ...
1.2. Should the results of measurements be challenged, measurements shall be carried out in such a way as to meet the following requirements: 1.2.1. the distance of measurement shall be such that the law of the inverse of the square of the distance is applicable;
1.2.2. the measuring equipment shall be such that the angular aperture of the receiver viewed from the reference centre of the lamp is between 10' and 1 C.
