Can Flexible Duct be exposed to ultraviolet light sources or sunlight?

No, flexible duct must be protected from the weather, including sunlight. In the late 1980’s, manufacturers of insulated flexible duct discovered that the products with gray polyethylene jackets could fail when exposed to direct or indirect sunlight. The ultraviolet rays in the sunlight would break the chemical bonds in the gray polyethylene jackets causing them to disintegrate over a period of several years. To alleviate the problem, manufactures began using black polyethylene jackets and metallized polyester jackets. The carbon black used to color the black polyethylene jackets has an inherent resistance to ultraviolet light as so is the metallized polyester. Since the change, the problem has been eliminated. However, most manufacturers still require that insulated flexible duct of any type not be installed in areas with direct or indirect sunlight. We are confident of the quality of our flexible duct products.

If you have a duct that will be exposed to Ultraviolet light from the use of a Bio-treatment lamp or UV lamp, we suggest you use our Ultra-Flex Duct Kit. It is specifically designed to be used where UV light from a Bio-treatment lamp is emitted onto the core of a non-metallic flexible duct.