Tests of the durability of a paint coating under severe weather conditions are essential. Test panels of wood and steel are prepared with the coating system under investigation and exposed to the weather. Racks to carry sets of panels are normally installed in the open, the panels being inclined at an angle of 45° and facing a specific direction. a southern aspect is often selected in

the United Kingdom and Florida.

In Arizona, USA, the tracks are so designed that they can move equatorially during hours of daylight and the intensity of the radiation is also increased by the use of strategically placed mirrors.

Panels can also be sprayed with water as required. The test panel usually has a covered portion, so any degradation of film properties or colour can be assessed.

The durability of paint in service will depend upon many factors; variable weather conditions, exposure position, light, wind. Humidity, etc. The Arizona exposures probably represent the harshest light exposure conditions available naturally, but the results may still show variations.