The AMCA 250 Standard Updated standards for parking garage engineers and designers outlining the details within the newest revision of AMCA/ANSI Standard 250-22
Jet Fan Key Performance Metrics There are four key performance metrics regarding the overall performance of a jet fan. They are: Thrust, Airflow, Throw, Induction Factor Thrust Commonly expressed as Newtons (N) or pound-force (lbf) Thrust, a primary measurement of a jet fan, is the force exerted by the fan. Thrust is dependent on the outlet air velocity, shape, and direction. Thrust is obtained from laboratory testing in accordance with AMCA Standard 250. ANSI/AMCA Standard 250, Fig. 4B, p.
Throw Commonly expressed as feet (ft) or meters (m) Throw length describes the farthest distance a jet fan can push air, specified by a terminal velocity of 1 m/s (196 fpm) at the end of the throw length. The longer the throw length, the more effective jet fans are in optimizing garage ventilation systems. Throw length is dependent on thrust, airflow, fan outlet shape, and airflow direction, and is generated from productspecific CFD analysis using AMCA 250 data.
Certified Performance Data of Jet Fans: Accuracy Leads to Safety Before October 2018, AMCA allowed manufacturers to certify jet fan data with measured airflow methods.
ANSI/AMCA Standard 210/ASHRAE Standard 51 and ISO 5801 provide methods to measure airflow, but not thrust. While measuring airflow is accurate for ducted products, this method does not consider the unducted application of jet fans. Jet fans produce an impulse of air that increases the momentum of air moving within a tunnel or parking garage space. This impulse of air, known as thrust, is difficult to predict with measured airflow.
What Are the Key Metrics of a Jet Fan? The key metrics of a jet fan include thrust, airflow, throw, and induction. Thrust measurements and airflow calculations, obtained from AMCA 250 testing, are the foundation of other key metrics designers seek when implementing a jet fan system. These other key metrics, such as throw and induction, are the result of Computational Fluid Dynamics (CFD) simulation.
References 1 Air Movement and Control Association International, INC. Thrust Measuring Layout: Supported Method with linear Bearings and Transducer Measuring System. “ANSI/AMCA Standard 250-22 - Laboratory Methods of Testing Jet Fans for Performance.” AMCA. Figure 4B, 2022, P. 25. 2 Air Movement and Control Association International, INC. “AMCA Testing Jet Fans per ANSI/AMCA Standard 250 Thrust Method.” AMCA. Press Release, 12 Feb. 2020. https://www.amca.
sales@systemair.net www.systemair.net Systemair Inc.
