Accelerated aging studies are primarily performed in accordance with ASTM G154. ASTM G154 testing uses fluorescent light sources that can simulate UVA or UVB. This technique is used to evaluate the impact of UV exposure on a product’s mechanical properties.
This method is used for evaluating accelerated weathering on plastics, adhesives and sealants, printing inks and coatings. It is also used for doing accelerated weathering on a lot of finished products including roofing materials and outdoor household products.
The test involves cycles of condensation and UV exposure. Default cycling is as follows: 4 hrs of UV with 313 nm lamps at 60 C and 4 hrs of condensation at 50 C.
Test specimens are loaded in the UV chamber as shown in the figure below and subjected to the selected UV and Condensation cycles (either at predefined standard cycles or specified by customer). UV lamp replacement procedure was followed after every 400 hours of UV exposure as required by the relevant standard. This ensures consistent exposure energy to the composite material.
These cycles are continued for extended periods of time – some up to thousands of hours.
Performance comparisons under controlled conditions of accelerated weathering can be compared to documented performance of the materials and coatings that have experienced extended periods of end use exposure.