What is the maximum velocity of square throat, sheet metal elbows without turning vanes?

The maximum velocity of air flowing through square throat sheet metal elbows without turning vanes is typically set at 1000 feet per minute (FPM). This is important because higher velocities can lead to increased pressure drop and noise levels within the ductwork. Without turning vanes, airflow can become turbulent, causing further inefficiencies and potential damage to the duct system over time.

Adhering to the 1000 FPM limit helps to maintain optimal performance and longevity of the HVAC system, thereby ensuring efficient operation and consistent delivery of conditioned air. Factors like duct size, air density, and system design also play a role, but the 1000 FPM standard is widely accepted in the industry for systems using elbows without turning vanes. This standard helps to balance airflow, noise, and the overall efficacy of HVAC systems.