This Part of EN 13523 specifies the procedure for evaluating the behaviour of an organic coating on a metallic substrate during and after outdoor exposure. Panel design, preparation and the procedure for outdoor exposure are to be performed in accordance with EN 13523-19. After washing of the panel some dirt can remain on the panel. This remaining dirt can influence the accuracy and precision of readings of gloss and colour, performed on exposed panels, although carried out in accordance with the standards. Unlike other precise measurements, the objective of this Part of EN 13523 is to report on trends in the corrosion and/or paint degradation behaviour of coil coated panels.