Vektor-CD Performance Catalog - Greenheck

AMCA 260 Air Test Procedure
The following illustrations describe the procedure for determining the total laboratory exhaust fan discharge flow.
The total discharge flow is the sum of fan flow and entrained dilution airflow. The key requirement to AMCA 260
is the AMCA Accredited variable resistance box. This box allows the fan to be discharged into the air chamber
(Ps = 0 in. wg to simulate discharging the fan to atmosphere) at all points along its fan curve.
Without the variable resistance box, the entrained dilution airflow can only be measured at the free air point of its
fan curve. The entrained dilution airflow obtained can be used to calculate an effective plume height. Therefore,
AMCA 260 certification is necessary to ensure the laboratory exhaust fan specified is providing the plume rise
and entrainment submitted.
ANSI/AMCA 210 Figure 15 Test
Total Flow
Total Airflow
AMCA Accredited Air Test Chamber
Airflow
Flow Direction
Entrained
Air
Variable
Supply
System
Total Airflow Measurement
Determines inlet airflow (cfm).
Airflow
AMCA 260 Figure 1 Test
Variable Resistance Box
Flow Direction
AMCA Accredited Air Test Chamber
Total Flow
Flow Direction
Total Flow Airflow
6
Entrained
Air
Ps = 0 in. wg*
Total Airflow Measurement
*To simulate atmospheric conditions
Determines outlet airflow (cfm) at the same inlet
conditions measured in the Figure 15 test.
Variable
Exhaust
System