Document ID: chunk:federal_register_of_legislation:F2023C00142:reg:21:p13
Version: federal_register_of_legislation:F2023C00142
Segment Type: reg
Provision Reference: reg 21 (pt 13/15)
Character Range: 66440–69234

with that of the test mixture prescribed.
         During the period of application, it is permissible to compensate the pressure applied to the sample in order to prevent it from causing cracks.
         2.2.2.3. Cleaning
         At the end of the application of the test mixture, the samples shall be dried in the open air and then washed with the solution described in paragraph 2.3. (Resistance to detergents) at 23 degrees C +/- 5 degrees C.
         Afterwards the samples shall be carefully rinsed with distilled water containing not more than 0.2 % impurities at 23 degrees C +/- 5 degrees C and then wiped off with a soft cloth.
         2.2.3. Results
         2.2.3.1. After the test of resistance to atmospheric agents, the outer face of the samples shall be free from cracks, scratches, chipping and deformation, and the mean variation in transmission
         deltat = (T2 - T3)/T2, measured on the three samples according to the procedure described in appendix 2 to this annex shall not exceed 0.020 (deltatm < 0. 020)
         2.2.3.2. After the test of resistance to chemical agents, the samples shall not bear any traces of chemical staining likely to cause a variation of flux diffusion, whose mean variation deltad = (T5 - T4)/T2, measured on the three samples according to the procedure described in appendix 2 to this annex shall not exceed 0.020 (delta dm < 0.020).
         2.2.4. Resistance to light source radiations
         The following test shall be done:
         Flat samples of each light transmitting plastic component of the headlamp are exposed to the light of the gas-discharge light source.  The parameters such as angles and distances of these samples shall be the same as in the headlamp.  These samples shall have the same colour and surface treatment, if any, as the parts of the headlamp. After 1,500 hours of continuous exposure, the calorimetric specifications of the transmitted light must be met with a new standard gas-discharge light source, and the surfaces of the samples shall be free of cracks, scratches, scalings or deformation.

         2.3. Resistance to detergents and hydrocarbons
         2.3.1. Resistance to detergents
         The outer face of three samples (lenses or samples of material) shall be heated to 50 degrees C +/- 5 degrees C and then immersed for five minutes in a mixture maintained at 23 degrees C +/- 5 degrees C and composed of 99 parts distilled water containing not more than 0.02 % impurities and one part alkylaryl sulphonate.
         At the end of the test, the samples shall be dried at 50 degrees C +/- 5 degrees C.  The surface of the samples shall be cleaned with a moist cloth.
         2.3.2. Resistance to hydrocarbons
         The outer face of these three samples shall then be lightly rubbed for