Document ID: chunk:federal_register_of_legislation:F2023C00155:body:0:p10
Version: federal_register_of_legislation:F2023C00155
Segment Type: other
Provision Reference: 
Character Range: 25919–28647

(E4) under the number 00243.  The first two digits of the approval number indicate that the approval was granted in accordance with the requirements of Regulation No. 50 in its original form.

For a direction indicator, the arrow indicates that the luminous distribution is asymmetrical in a horizontal plane and that the photometric values required are satisfied up to an angle of 80 degrees to the right, the device seen in the opposite sense of the light emitted.

Note

   1. The approval number must be placed close to the circle and either above or below the letter "E" or to the left or right of that letter.  The digits of the approval number must be on the same side of the "E" and face in the same direction.  The use of Roman numerals as approval numbers should be avoided so as to prevent any confusion with other symbols.

   2. In the case of the filament lamps mentioned in foot-note 4 of paragraph 7.1 of this Regulation, the filament lamp shall be marked with the letter "M".

       Annex 4

       PHOTOMETRIC MEASUREMENTS

       1. MEASUREMENT METHODS

       1.1. During photometric measurements, stray reflections shall be prevented by appropriate masking.

       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 measurements 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 degrees;

       1.2.3. the intensity requirement for a particular direction of observation shall be deemed to be satisfied if that requirement is met in a direction deviating by not more than 15' from the direction of observation.

       2. STANDARD LUMINOUS INTENSITY DISTRIBUTION TABLE

       2.1. The direction H = O degrees and V = O degrees corresponds to the reference axis. (On t' vehicle it is horizontal, parallel to the median longitudinal plane of the vehicle and oriented in the required direction of visibility). It passes through the centre of reference. The values shown in the table give, for the various directions of measurements, the minimum intensities as a percentage of the minimum required in the axis for each lamp (in the direction H = O degrees and V = O degrees).

       2.2. Within the field of light distribution of paragraph 2, schematically shown as a grid, the light pattern should be substantially uniform so that the light intensity in each direction of a part of the field formed by the grid lines meets at least the lowest minimum percentage value being shown on the