What is the maximum length of listed air duct material?

The maximum length of listed air duct material is not limited, meaning that there isn't a specific maximum length mandated by the code for these ducts. This allows for flexibility in installation, accommodating various building designs and requirements. While there may be specific installation guidelines and considerations regarding support, handling, and airflow efficiency, the absence of a maximum length ensures that professionals can design ductwork systems that effectively meet the needs of both residential and commercial environments.

For instance, when installing ductwork, factors such as pressure drop, air velocity, and system configuration might influence the length of duct runs. Although practical considerations may dictate shorter lengths in some scenarios, code provisions recognize the need for a system that can be tailored to diverse building layouts without imposing arbitrary restrictions on duct length. This approach supports efficient design practices while adhering to safety and performance standards.