What additional length should be added for most 90° bend fittings in a clothes dryer duct?

In ductwork, especially in a clothes dryer duct system, the length added for fittings is necessary to account for the increased resistance to airflow that these bends create. A 90-degree bend significantly affects the airflow, and it's important to calculate this in the total duct length to ensure efficient operation and proper ventilation.

Adding 5 feet for most 90-degree bend fittings is a common standard. This figure represents a guideline to compensate for the equivalent length that the airflow experiences due to the bend. It's essential to consider these adjustments in duct length during installation and maintenance to maintain optimal efficiency and safety standards.

Failure to account for this additional length could result in airflow problems, increased drying times, or even the risk of dryer overheating or lint accumulation, leading to more serious hazards, such as fires. Therefore, the practice of adding 5 feet for each 90-degree bend in dryer duct systems is well-supported in duct design principles.