Standard and ANSI/ASHRAE Standard 51, except as modified by Units shall be tested in accordance with ANSI/AMCA Standard /ANSI/ASHRAE. Standard — Laboratory Methods of Testing Fans for Aerodynamic Performance Rating (ANSI/AMCA Standard ) (ANSI/ASHRAE Approved). and Air-Conditioning Engineers (ASHRAE) approved ANSI/AMCA Standard ANSI/ASHRAE Standard , Laboratory Methods of Testing Fans for.
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Therefore, it is the difference between static pressure at the fan outlet and total pressure at the fan inlet.
Blow through verification test. Traverse duct shall be round within 0. Repeat steps 3 and 4 until Qc, Ptc and Hc do not change or are of ashrea accuracy. A motor shall be calibrated throughout its range of use against an absorption dynamometer except as provided in Section 4.
The absorption dynamometer shall be calibrated by suspending weights from a torque arm. The static calibration shall be accomplished by suspending weights from a torque arm.
The test chamber is pressurized and the valve is closed. Since air is compressible, thermodynamic effects influence output 51-70 a compressibility coefficient Kp must be applied to make power output proportional to QPt . This standard applies to a fan or other air moving device when air is used as the test gas with the following exceptions: The airflow rate Q4 at the entrance to a ducted ashraf shall be calculated from: The unit of time is either the minute min or the second s in both systems.
The larger size is helpful in preventing blockage due to dust, water, ice, etc.
See Annex B for two recommended leakage test methods. In order to simplify this analysis, test results will be considered to be the curves of fan static pressure versus fan airflow rate and fan static efficiency versus fan airflow rate.
Groups approve laboratory methods for testing fans.
The instruments and apparatus used in the test shall be listed. Using ideal gas law: Normative References The following standards contain provisions that, through specific reference in this text, constitute provisions of this American National Standard. Hollow flexible tubing used to connect measurement devices to measurement locations should be of relatively large inside diameter.
Assuming the uncertainties are small, the characteristic curves and parabola can be replaced by their tangents, and the effects of uncertainty in each measurement, Xon the characteristic uncertainty can be determined.
The nozzle discharge coefficient C shall be calculated from: A derivation of the fan total efficiency equation based on compressible flow values follows .
The unit of pressure is the Pascal Pa ; the I-P unit is either the inch water gauge in. The recommended approximation which meets these requirements is shown in Figure 4B by Cermak, J. Since the air velocity in an inlet chamber is considered uniform due to the settling means employed, a single measurement is representative of the average chamber pressure.
When a cell straightener is used: When a reaction dynamometer is used to measure torque, the fan power input H shall be calculated from the beam load Fusing the moment arm l and the fan rotational speed N using: Since only one set of observations is specified in the standard, this analysis must deal with the uncertainties in the results obtained from a single set of observations.
The gas constant R, for air, may be taken as Variable exhaust system may be an auxiliary fan or a throttling device. This is the fundamental relationship of the fan laws. Each result is based on one or more measurements.
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An examination of x and z will reveal that x is the ratio of the totalpressure rise to the absolute total pressure at the inlet, and that z is the ratio of the total-temperature rise to the absolute total temperature at the inlet. Test Setups and Equipment. An outlet duct with a Piezometer ring shall be at asgrae 10 diameters long with the Piezometer plane located between 8.