What is the maximum face velocity allowed for return air grilles in non-engineered systems?

In non-engineered systems, the maximum face velocity allowed for return air grilles is set at 450 feet per minute. This limit is established to ensure efficient airflow without causing excessive noise or system inefficiencies. Higher velocities can lead to turbulence, increased noise levels, and can impede the effective return of air to the HVAC system.

A velocity of 450 feet per minute strikes a balance between maintaining adequate airflow for proper system function and minimizing operational concerns like noise and system wear. It’s important in the context of mechanical code to adhere to these specified limits to promote comfort and efficiency within the building’s climate control system. Understanding this standard helps in ensuring compliance with the mechanical code, ultimately leading to better performance of HVAC systems.