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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AMCA Publication R – Free Download PDF

Referenced Planes Certain locations within a fan-system installation are significant to field tests. Refer to Section Jolette AMCA Staff Disclaimer AMCA uses its best efforts to produce standards for the benefit of the industry and the public in light of available information and accepted industry practices.

The ducts should be a minimum of one equivalent diameter in length, and have flared inlets to reduce entrance losses and provide more uniform velocity profiles at the pressure measurement planes.

In this method for testing a nonducted fan, consider the fan static pressure Ps as the differential pressure, as read on a manometer, between the pressure measured inside the room Ps3 and the pressure measured outside the room in the a,ca of the ventilator outlet Ps2. Limit the use of the calculation procedure that is based on perfect gas relationships and illustrated in Example M2. When intending to use this method, it is usually necessary to specify in the motor purchase arrangements that the motor be calibrated since an additional cost is normally involved.

Measure the fan speed and the motor amps, volts, and if possible, watts. All of these measurements are used in the determination of densities at the various amxa of interest. If the flow conditions at the traverse plane are less than satisfactory, the accuracy of the determination of flow rate may be improved by using more than the recommended minimum number of points. Measure the fan speed and the motors amps, volts, and if possible, watts. Measure A3a and A3b, the areas of the traverse planes and A1a and A1b, the areas of the inlets to the inlet dampers.

AMCA Publication 203-90 (R2007), “Field Performance Measurement of Fan…

The double reverse tube cannot be used to measure static pressure directly. The length of the duct should be a minimum of twice its publicatin or equivalent diameter, and the entrance to the duct should be flared in order to reduce the entrance loss. The sum of the static pressure, Ps1, and velocity pressure, Pv1, at the inlet to the unit amcz is considered to be equal to the sum of the static pressure, Psx, and velocity pressure, Pvx, at a point sufficiently distant from the inlet as to be in still air.


The static pressure at a plane of measurement x is calculated as follows: Variable inlet vane controls or inlet box dampers must be set in the full open position for the duration of the test, except when testing for control characteristics.

Pulbication A3, the area of the traverse plane, located at the tip of the Pitot-static tube and A1, the area of the inlet to the damper. Measure Ps1a and Ps1b at locations close to the entrances to the inlet boxes and in planes which are substantially equal in area to the publiccation of the entrances to the inlet boxes Plane 1.

AMCA Publication 203 R2007

Pressure loss data supplied by manufacturer of outlet damper. The fan flow rate is the volume flow rate at the fan inlet density.

The following motor performance data was supplied by the motor manufacturer: In most cases, the static pressure measurements for use in determining fan static pressure will not be made directly at the fan inlet and outlet, but at locations a relatively short distance upstream from the fan inlet and downstream from the fan outlet. If there is a change in area between the measurement plane and the plane of interest, then the calculation of the static pressure at the plane of interest must account for velocity pressure conversion and include any associated pressure loss.

Since flue gas is being handled by the fan, the Orsat apparatus is used by process personnel to determine the density of the gas. Axial fans are often rated in Fan Total Pressure.

In order to calculate the value of SEF 1, it is necessary to measure the length of the outlet duct, L; the outlet area of the fan, A2; and the blast area of the fan. The calculations of these losses are based on the assumption of uniform flow conditions.

Most of the instruments require frequent calibration, and some are not suited for use in high temperature, dirty, wet, corrosive, or explosive atmospheres. Similarly, for static pressure at the fan outlet, Ps2: Fan pub,ication measurement was not obtained due to 20390 closed duct arrangements on both sides of the fan.

Measure A4 and A5, the cross-sectional areas of the duct connections at the static pressure taps. For practical considerations, it is not normally used in cases where the fan is belt driven and where the fan impeller is installed directly on the motor shaft. In this method for testing a free inlet, free outlet fan, the fan static pressure is calculated as the static pressure on the outlet side of the fan less the static pressure on the inlet side of the fan: On occasion, an undesirable traverse plane location is unavoidable, or each of a limited number of prospective locations lacks one or more desirable qualities.


However, the cost publicahion the calibration is a limiting factor in the use of this method in field tests. When the fan is ducted outlet, the static pressure measurement plane downstream of the fan should be situated a sufficient distance from the fan outlet to allow the flow to diffuse to a more uniform velocity distribution and to allow the conversion of velocity pressure to static pressure.

The power output of three phase motors can be estimated based on the relationship of motor current and motor power output.

Measure td3 and tw3 near the entrance to the short inlet duct. In order to be able to compare the field test results to the fan performance ratings, it is essential that these items be fixed in their full open positions for the duration of the test.

In this example, a measurement plane which provides a satisfactory velocity profile cannot be located within the short length of duct between the point of connection of the branch ducts and the ventilator inlet.

For Plane 3 conditions of: Measure the fan speed and the motor amps and volts. SEF 1 is due to the effect of insufficient distance between the amcs inlets and the side walls of the fan cabinet.

The unusual duct arrangement in this example makes it very difficult to obtain accurate pressure measurements, and this fact should be understood before testing begins. Failure to release simultaneously may result in manometer fluid being blown from the manometer. When it is necessary to publicwtion more than one 203–90 plane in order to account for the total flow: It may be necessary amcq lock out, lublication or otherwise modify automatic control devices in lublication to prevent the positions of the dampers and the temperature of the coil from upblication during the test.

For low horsepower applications, the fan manufacturer may be able to calibrate a motor. For a blast area ratio of 0.

The distance is 2. AMCA R 3 Install a duct on the inlet side of the fan for the purpose of providing a location for the velocity pressure measurement plane. In each case, the conditions which exist at the plane of measurements are assumed to exist at the respective plane of interest because of the close proximity and the fact that the two planes are equal in area.

In order to calculate the value of SEF2, it is necessary to measure the outlet area of the fan, A2.