Common use of Measurement methods Clause in Contracts

Measurement methods. 5.6.2.1. When photometric measurements are taken, stray reflections shall be avoided by appropriate masking. 5.6.2.2. In the event that the results of measurements are challenged, measurements shall be taken in such a way as to meet the following requirements: 5.6.2.2.1. The distance of measurement shall be such that the law of the inverse of the square of the distance is applicable; 5.6.2.2.2. The measuring equipment shall be such that the angle subtended by the receiver from the reference centre of the light is between 10′ and 1°; 5.6.2.2.3. The intensity requirement for a particular direction of observation shall be satisfied if the required intensity is obtained in a direction deviating by not more than one quarter of a degree from the direction of observation. 5.6.2.3. Measuring points expressed in degrees of angle with the axis of reference are shown in Annex 4, Figure A4-XII. The values shown in the table give, for the various directions of measurement, the minimum intensities in cd. 5.6.2.4. Horizontal and vertical angles for the field of geometric visibility are shown in Annex 4, Figures A4-XIII. The directions H = 0° and V = 0° correspond to the axis of reference. On the vehicle they are horizontal, parallel to the median longitudinal plane of the vehicle and oriented in the required direction of visibility. They pass through the centre of reference.