HVAC Journeyman Practice Exam 2026 - Free HVAC Practice Questions and Study Guide

The maximum length allowed for commercial clothes dryer exhaust ducts, which includes consideration for two 90-degree elbows, is indeed 16 feet. This measurement is critical to ensure the efficient removal of lint and moisture from the dryer, which helps prevent excessive buildup that can lead to fire hazards or dryer inefficiency.

In commercial settings, the longer the duct run, the greater the resistance to airflow, which can impede the dryer’s performance. The figure of 16 feet takes into account the added resistance caused by elbows. Each 90-degree elbow effectively adds extra length to the duct system, which impacts the overall airflow.

For optimal performance and safety, adhering to these specifications is essential, and various safety codes and standards, including those from the International Mechanical Code (IMC) and National Fire Protection Association (NFPA), support this guideline. By following this maximum length, you ensure that the system can vent properly, reducing any risks associated with poor ventilation in commercial settings.