Common use of Measurement methods Clause in Contracts

Measurement methods. 4.8.2.1. The photometric performance shall be checked in accordance with the relevant sub-paragraph of paragraph 4.7. 4.8.2.2. For multiple replaceable light sources: When equipped with light source(s) at 6.75 V, 13.5 V or 28.0 V, the luminous intensity values produced shall be corrected. For these replaceable filament light sources 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). For LED light sources the correction factor is the ratio between the objective 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 light source used shall not deviate more than 5 per cent from the mean value. Alternatively, and in case of filament light sources only, a standard filament light source 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. 4.8.2.3. For lamps except those equipped with filament light source(s) 4.8.2.3.1. For reversing lamps and maneuvering lamps, the luminous intensities measured after one minute and after 10 minutes of operation, shall comply with the minimum and maximum requirements. The luminous intensity distribution after one and after 10 minutes of operation shall be calculated from the luminous intensity distribution measured after photometric stability has occurred by applying at each test point the ratio of luminous intensities measured at HV: (a) After one minute; (b) After 10 minutes; and (c) After photometric stability has occurred. 4.8.2.3.2. For all other lamps, the luminous intensities measured after 1min and after 30min of operation shall comply with the minimum and maximum requirements. Operation of direction indicator lamps shall be done in flashing mode (f = 1.5 Hz, duty factor 50 per cent). The luminous intensity distribution after 1min of operation can be calculated from the luminous intensity distribution after 30 min of operation by applying at each test point the ratio of luminous intensities measured at HV after 1 min and after 30 min of operation.