Backed by our unmatched breadth and depth of expertise, UL has helped develop the industry standards for air ducts, air connectors and closure systems. In fact, the UL Mark is one of the most recognized and accepted certification marks in the industry.

We provide a full range of services, including physical examinations such as corrosion resistance, mold growth and humidity, high and low temperature, puncture, impact, erosion, positive and negative pressure, and leakage. We also offer flammability examinations, including surface burning characteristics, flame penetration and burning tests.

Air ducts and air connectors are listed as class 0 or class 1 and installed in accordance with the requirements in the standards of the National Fire Protection Association (NFPA) for the Installation of Air-Conditioning and Ventilating Systems (NFPA 90A), and the Installation of Warm-Air Heating and Air Conditioning Systems (NFPA 90B). Air ducts and air connectors are also evaluated to UL 181, the Standard for Factory-Made Air Ducts and Air Connectors. Closure systems consisting of either tapes or mastics or polymeric mechanical fasteners are evaluated according to UL 181A and/or UL 181B. Clothes dryer transition ducts are evaluated according to UL 2158A and air dispersion system materials are evaluated to Outline of Investigation UL 2518.

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