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 (∆tm &lt; 0.020).
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 (∆tm &lt; 0.020).