BOAF Interpretations

Interpretation #8848

Original Request

Requested By: Milan Slovak
Requester E-Mail: mslovak1@yahoo.com
Code Version: 2021
Code: MECHANIC
Code Description:
Chapter:
Section: 603.6
Topic: Flex Duct Length
Question: Is the length of flex duct limited by 603.6.2.1?

Answer:

Ducts and Connectors are different products. The limitation of flexible air connectors does not apply to ducts. Please see the attached commentary

On 11/21/2023 at 1:19 PM

Commentary:

Flexible air duct and flexible air connectors are similar in appearance causing confusion of their identification and sometimes resulting in improper use. The listing label on “flexible duct” is rectangular in shape and states “Listed Air Duct.” The listing label on a flexible air connector is circular in shape and states “Listed Air Connector.” Both are listed to UL 181 requirements. The length of a “flexible air connector” is limited to 14 feet maximum. The length of a “flexible air duct” is not limited in length. For a complete listing of the limitations of use of flexible air ducts and flexible air connectors, refer to the manufacturer’s installation instructions and refer to UL Product iQ website for listing information (https://iq.ulprospector.com/en)

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