AMCA Publication (R) Field Performance Measurement of Fan Systems AIR MOVEMENT AND CONTROL ASSOCIATION. use of probes capable of indicating both flow direction and velocity pressure. The AMCA Publication ‘Field Performance. Measurements’ and the AMCA. AMCA International has reaffirmed AMCA Publication. , Field Performance Measurement of Fan Systems. Recommendations in this publication may be.

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The conditions which exist at Plane 5, including the static pressure, are assumed to exist at Plane 2, based on their close proximity and the fact that there is no change in area between the two planes. Also referred to as impact reverse tube, combined reverse tube, and type S tube.

AMCA Publication R – Free Download PDF

The equation for fan static pressure is: Determine fan power input by using the motor power output and, where applicable, the power transmission loss. It is recommended that the Pitot-static tube be publicaton so that its nose amcw aligned with the anticipated flow streams, particularly near the walls of the diffuser.

For rectangular ducts with cross-sectional areas of 24 square feet and less, the recommended minimum number is If the motor power output is to be estimated by using the phase current method described in Annex K, it is not necessary to measure motor watts; however, it may publicxtion necessary to disconnect the drive and measure the no load amps NLA 230-90 the motor is not operating at or near its full load point refer to Annex K.

The minimum Pitot tube stem diameter recognized under this standard shall be 0. On occasion, an undesirable traverse plane location is unavoidable, or each of a limited number of prospective locations lacks one or more desirable qualities. Motor performance data, supplied by the motor manufacturer, are used in the determination of motor power output in this example. This annex contains examples illlustrating the procedures for determining densities. H20 Must be leveled carefully 3.

If a 58 Pitot-static tube 203–90 used, it should be positioned well within the inlet collar in which Plane 1 is located.

AMCA Publication 203 R2007

Measure the fan speed and motor amps, volts, and if possible, watts. However, the amount of conversion will be very small relative to the static pressure measured at Plane 3 and ignoring any change in static pressure from Plane 3 to Plane 2 will have no appreciable effect on the test results. This publication offers guidelines to making performance measurements in the field which are practical and flexible enough to be applied to a wide range of fan and system combinations.


Measure td3 and tw3 in the traverse plane; td1 is assumed to be equal to td3. The basis for these calculations is described in Section maca In order to determine the proper field test procedure and to provide a valid basis for comparing field test results to the fan performance ratings, it is important to establish which of these items are considered a part of the fan and which are considered a part of the system.

This alternative course of action is recommended when swirl exists at the fan inlet see PublicationFigure 9. Hg Use the modified Apjohn pkblication for partial vapor pressure and the density equation based on perfect phblication relationships, both of which are described in Annex M, and the data in Figure N.

The duct, temporarily installed for purposes of the test, is square in cross-section. The publcation, as indicated in the diagram, is to make a velocity pressure measurement traverse in each branch.

Amcca to Field Tests In some cases, considerations such as cost and problems of making accurate measurements may make the following alternative methods of testing worth investigation: Ps2, the static pressure at the outlet of the ventilator, is zero gauge pressure, referred to the atmospheric pressure in the region of the ventilator outlet. Distribution of Traverse Points In order to obtain a representative average velocity in a duct, it is necessary to locate each traverse point accurately.

The effect created by this fitting is considered to be equivalent to the effect created by having no duct at the fan outlet. The adjustable range type is convenient in that it may be adjusted at the test site upblication the range appropriate to the velocity pressures which are to be measured.


The static pressure at a plane of measurement x is calculated as follows: The basis for calculations is described in Section Measure td3 in Plane 3. Determine pb for the general vicinity of the air conditioning unit.

The air performance ratings for this type of unit are based on the operation of the fan section assembly only, but include the effects of the air flow conditions 19 AMCA R entering and leaving the fan section which are created by accessory equipment such as plenums, coils, filters, mixing boxes, publlication.

However, this uncertainty can be controlled by selecting a manometer with a slope suited to the velocity pressures to be measured and by avoiding regions of very low velocity in the selection of the traverse plane location. The points are to be located in the centers of equal areas with the areas as nearly square as practical see Figure H. In order to be able to compare the test results to the fan performance ratings, it is essential that publucation damper be fixed in the full open position for the duration of the test.


The double reverse tube is connected to the inclined manometer as shown in Annex C.

The static pressures at the fan inlet and outlet may be obtained directly by making pressure measurements at these locations; or they may be AMCA R determined by making pressure measurements at other locations, upstream and downstream of the fan. Pressure transducersstrain gauge, capacity, potentiometer, crystal, magnet Remote reading, responds to rapid changes of pressure 0.

These curves indicate that if you average the results of Equation A and Equation B for a specific measured amcca draw, that your results approach the typical calibration curve. The equations for the conversion are as follows. The subject of publiation test in this example is the roof ventilator assembly.

publicatoon The following motor performance data was supplied by the motor manufacturer: The subject of the test is the fan section, which is rated by the manufacturer as an assembly of the fan and the cabinet in which the fan has been installed. Mark the double reverse tube to indicate the direction of the gas flow used in its calibration. Refer to Annex K. This includes pressure losses in ducts, duct fittings, and other system components. It is essential that the blade pitch angle be fixed for the duration of the test.

Since the inlets to the inlet dampers Planes 1a and 1b are located shortly downstream of the traverse planes Planes 3a and 3b in an airway of uniform cross-section, the conditions which exist at the traverse planes are publidation to exist at the inlets to the inlet dampers.

Avoid situations requiring these determinations, thereby eliminating them as sources for uncertainties. Improve the accuracy of the flow rate determination by avoiding these conditions in the selection of the traverse plane location, or improve the conditions by modifying the system.

Diameter of the fan inlet: The information regarding the basis of the rated fan power input accompanies the rating data or is otherwise available from the fan manufacturer. Both types require calibration.

Measure the fan speed and the motor amps, volts, and if possible, watts for each fan.

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