Document ID: chunk:federal_register_of_legislation:F2023C00153:front:0:p19
Version: federal_register_of_legislation:F2023C00153
Segment Type: other
Provision Reference: 
Character Range: 52681–55547

surface of 14 x 14 mm.
During this 10-minute period, the cloth pad shall be soaked again with the mixture so that the composition of the liquid applied is continuously identical 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
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
on the three samples according to the according to the procedure described in appendix 2 to this annex shall not exceed 0.020 (deltadm < 0.020).
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 one minute with a cotton cloth soaked in a mixture composed of 70 % n-heptane and 30 % toluene (volume %), and shall then be dried in the open air.
2.3.3.                              Results
After the above two tests have been performed successively, the mean value of the variation in transmission
measured on the three samples according to the according to the procedure described in appendix 2 to this annex shall not exceed 0.020 (deltadm < 0.020).
2.3. Resistance to detergents and hydrocarbons
2.3.1.                              Resistance to detergents
The