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Technical Articles

UV Stabilized Body Materials

UV Stabilized Valves

PVC and polypropylene valves are highly weather resistant, but will become oxidized after extended exposure to ultra-violet light. UV rays affect valves by degrading the molecular structure of the polymer. The degree of oxidation is dependent on the level and intensity of exposure: In sunlight, oxidation can take a number of years and will result in discoloration and embrittlement. This does not affect performance or pressure capacity – so you may not have a problem – but it does make the valve vulnerable to impact damage. When a PVC or polypropylene valve is connected to a UV sterilizer, the level of exposure is much greater and the thermoplastic is eventually prone to stress cracking. For UV sterilizers, PVDF is generally the valve material of choice and is not subject to the same type of degradation. In outdoor applications, heavily pigmented common latex paint will inhibit the damage from sunlight. In some situations, however, painting may not be practical. In polypropylene applications, paint does not properly adhere to the thermoplastic. PVDF may not be cost-effective or desired in certain applications either. Plast-o-Matic now offers UV-Resistant thermoplastics as an optional valve material for applications exposed to UV where paint or PVDF is not practical. Manufactured from Grade 1, Type 1 PVC or polypropylene with added carbon black, these valves generally withstand UV exposure with less oxidation and molecular degradation. The added carbon black effectively blocks the UV component, and allows the valve to maintain its properties, even in installations with high UV exposure. UV-resistant PVC or polypropylene eliminates the need for paint and other costly maintenance techniques, yet costs only slightly more than standard resins. The UV-Resistant feature is available on most popular Plast-O-Matic valves up to 2″ pipe sizes. Minimum quantities apply and these materials may not be practical in every situation with UV exposure. To determine the best solution for your specific application, contact our Technical Sales Team in Cedar Grove at 973-256-3000.