Airflow-pressure loss characteristics of duct fittings for air-conditioning and ventilation systems are required when HVAC designers determine total pressure loss and select fans of appropriate capacities. More accurate characteristics contribute to reducing costs for initial installation and operation as well as to higher energy efficiency of the HVAC systems. This report verifies the accuracy of simplified test methods using a short duct attached to the tested air terminals, and compares results by the simplified method with the results by the precise method, which has already established.
