This paper summarizes the results of the research performed to evaluate the UVC (254 nm) photodegradation of different manufactured products such as sealants, filters, and other components used in HVAC systems. The photodegradation of the products was monitored using both surface elasticity and mass loss. The manufactured products evaluated in this paper contained fillers, plasticizers, fibers, etc., so that the long-term relationship between the rate of photodegradation and UVC irradiance was complicated by the accumulation of inorganic particles on the exposed surface and/or exposure of underlying fibers. For many of the products tested, the photodegradation versus exposure time plots at 1000, 4000, 7000, and 11,000 µW/cm2 had break points that coincided with morphological or compositional changes in the exposed surface. As opposed to the research to rank the UVC resistance of pure polymers (Kauffman and Wolf 2012), the majority of the results presented in this paper are better suited for identifying products that should not be used unprotected in HVAC areas receiving UVC radiation than for predicting functional lives.

Citation: ASHRAE Transactions, Volume 119, Part 1, Dallas, TX.