Document ID: chunk:federal_register_of_legislation:F2023C00140:body:0:p14
Version: federal_register_of_legislation:F2023C00140
Segment Type: other
Provision Reference: 
Character Range: 38674–41491

be such that the angle subtended by the receiver from the reference centre of the light is between 10' and 1°:

       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.

       3. In the case where the daytime running lamp may be installed on the vehicle in more than one or in a field of different positions the photometric measurements shall be repeated for each position or for the extreme positions in the field of the reference axis specified by the manufacturer.

       4. Photometric measurement of daytime running lamps

The photometric performance shall be checked:

       4.1. For non-replaceable light sources (filament lamps or other):

With the light sources present in the daytime running lamp, in accordance with paragraph 10. of this Regulation.

       4.2. For replaceable filament lamps:

When equipped with filament lamps at 6.75 V, 13.5 V or 28.0 V the luminous intensity values produced shall be corrected. The correction factor is the ratio between the reference luminous flux and the mean value of the luminous flux found at the voltage applied (6.75 V, 13.5 V or 28.0 V). The actual luminous fluxes of each filament lamp used shall not deviate more than ±5 per cent from the mean value. Alternatively standard filament lamp(s) may be used in turn, in each of the individual positions, operated at its reference flux, the individual measurements in each position being added together.

       4.3. For any daytime running lamp except those equipped with filament lamp(s), the luminous intensities, measured after one minute and after 30 minutes of operation, shall comply with the minimum and maximum requirements.  The luminous intensity distribution after one minute of operation can be calculated from the luminous intensity distribution after 30 minutes of operation by applying at each test point the ratio of luminous intensities measured at HV after one minute and after 30 minutes of operation.

       5. Table of standard light distribution

       3.1. The direction H = 0° and V = 0° corresponds to the reference axis.  (On the 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 measurement, the minimum intensities as a percentage of the minimum required in the axis for each daytime running lamp (in the direction H = 0° and V = 0°).

       3.2. Within the field of light distribution of paragraph 3 above schematically shown as a grid, the light pattern should be substantially uniform, i.e. in