An example of work exempt from permit requirements is which of the following?

An example of work exempt from permit requirements is which of the following?

• A. A humidifier added to a plenum
• B. Moisture exhaust duct venting on a residential clothes dryer
• C. Replacement of a minor part that does not alter the equipment
• D. A branch duct added to trunk line

Answer: (C)

Work that is exempt from permit requirements usually covers minor repairs or replacements that do not change the equipment’s capacity, performance, or safety. Replacing a minor part that does not alter the equipment fits this rule because it leaves the system’s size, function, and airflow unchanged, so no permit review is needed. In contrast, installing a humidifier on a plenum adds a new component and can affect airflow and humidity control, which is a modification that typically requires permitting. Installing or venting dryer exhaust involves new ductwork and safety considerations, also requiring permit review. Adding a branch duct to the trunk line changes the system’s layout and performance, so it would normally need a permit as well.

Work that is exempt from permit requirements usually covers minor repairs or replacements that do not change the equipment’s capacity, performance, or safety. Replacing a minor part that does not alter the equipment fits this rule because it leaves the system’s size, function, and airflow unchanged, so no permit review is needed.

In contrast, installing a humidifier on a plenum adds a new component and can affect airflow and humidity control, which is a modification that typically requires permitting. Installing or venting dryer exhaust involves new ductwork and safety considerations, also requiring permit review. Adding a branch duct to the trunk line changes the system’s layout and performance, so it would normally need a permit as well.