Virtually all plastic materials are susceptible to degradation under the influence of UV radiation, but the quality polycarbonates used in Fibox enclosures show high durability in this respect, too.
In European latitudes FIBOX enclosures can be used, without hesitation, in outdoor applications. Over the years a slight discoloration, especially of the transparent cover material, will occur. If this must be avoided, a sun roof is recommended.
In tropical latitudes the gray-colored material still performs with only some discoloration. This is due to the TiO used in the gray pigmentation in order to UV-stabilize the material. The transparent material, however, which absorbs the UV radiation throughout the material, will in due time (some years) not only turn yellowish, but the high impact resistance will decrease. But more than lowering the impact resistance, the transparent materials allow the UV radiation to detonate the components mounted inside the enclosure.
The polycarbonates used in FIBOX enclosures have been tested and approved by Underwriters Laboratories, Melville, N.Y. USA, in conformity with standard UL 508 par. 34; 16-22. This standard specifies testing 720 hours in ‘Weatherometer’ (intensified UV light combined with water spray). After testing the materials must retain 85% of the original values with respect to tensile and flexural strength, impact resistance, flammability, and glow wire ignition.