The design air temperature for air conveyed in flexible duct must be less than what temperature?

The design air temperature for air conveyed in flexible duct must be less than 250°F. This is due to the material properties of the flexible duct itself, which can limit the maximum temperature it can safely handle. Most flexible ducts are made from materials that can deteriorate or become damaged at elevated temperatures. Exceeding the 250°F threshold can compromise the integrity of the duct, leading to potential failures or safety hazards. Therefore, maintaining air temperatures below this limit ensures that the flexible duct system remains efficient and safe for operation.

Understanding the proper temperature limits helps ensure compliance with the North Carolina Mechanical Code, which is designed to promote safe and effective HVAC system installations.