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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When locating the traverse plane close to the fan, as is often done in order to minimize the effect of leakage, flow conditions upstream of the fan are usually more suitable. This consideration, which is the same as that used in the methods for testing fans for performance rating purposes, charges to the fan losses incurred in accelerating the air into the fan inlets and eliminates the inaccuracies which arise in any attempt to measure the velocity pressure and static pressure at the fan inlets.
This can be accomplished by converting the results of the field test to the speed and density conditions of the fan performance ratings. Refer to Section Alternatives 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: However, care must be exercised in obtaining representative test measurements in order to prevent the uncertainties from exceeding this value.
In order to calculate the values of the SEFs, it is necessary to measure the inlet area and the outlet area of the fan, A1 and A2; and the lengths of the inlet and outlet duct connections, L1 and L2. Also, determine pb in the same vicinity. In this example, a measurement plane which provides a satisfactory velocity profile cannot be located upstream of the fans or between the point of connection of the branch ducts and the outlets of the fans.
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.
Determine Ps4 by averaging the pressure measurements at each of four static pressure taps located near the fan inlet. This fan, as supplied and rated by the manufacturer, includes the inlet box damper and the inlet box.
The examples are presented in detail and cover several types of fansystem combinations.
AMCA Publication 203 R2007
This method for estimating the power output of three phase publicarion is based on the relationship of motor current and motor power output. Although the pressure and temperature of the gas stream must be obtained for each plane at which a density value is required, it is usually necessary to obtain additional data, such as the wet-bulb temperature, for only one plane in order to establish the densities at all planes. When the test value of barometric pressure is to be based on data obtained from a nearby airport, it is important that the data include publicationn barometric pressure for the airport site and the elevation for which the pressure was determined often the barometric pressure is corrected to sea level.
Although the word air is used when reference is made in the general sense to the medium being handled by the fan, gases other than air are included in the scope of this publication. This is due mainly to is high cost and the cost of its installation.
In the general application, having determined publicatioj flow rate and density at the traverse plane, the flow rate at any location, xin the fan-system installation may be calculated, publicatikn the density at ppublication location is known and the assumption noted above is valid, i. Although an elbow is located a short distance upstream of the fan, it is considered to produce no system effect since it is equipped with turning vanes and the average velocity through the elbow will be relatively low due to its large cross-sectional area.
Determine the area of the traverse plane, A3, which pkblication located at the tip of the Pitot-static qmca, as shown in the diagram, not at the location of the Pitot-static tube access holes in the diffuser. Performance ratings for fans with outlet dampers cover operation with the outlet damper in the full open position. Also, the temperature of the heating coil must be kept constant throughout the test period.
Ps2, the static pressure at the outlet of the fan, is zero gauge pressure, referred to the atmospheric pressure in the region of the fan outlet.
A calibrated motor may be used to determine fan power input. The density at Plane 2: Measure A4 and A5, the cross-sectional areas of the duct connections at the static pressure taps.
The subject of the test in this example is the roof ventilator assembly. Determine Pv3a and 203-900 by using the root mean square of the 203–90 pressure measurements made in Planes 3a and 3b. Distribution of Traverse Points In order to obtain a representative average velocity in a duct, it is necessary to locate each traverse point accurately. In this example, there are no suitable locations for traverse piblication for use in determining directly the flow rate publicatoon each fan.
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 order to determine the value of SEF 1, it is necessary to measure the outlet area and the blast area of one of the fans and the length, L, of its qmca duct. In the case of heating, ventilating, and airconditioning equipment, the field test procedure will depend on whether the equipment is a factory assembled central station unit, a built-up unit, or a packaged unit see Section We need your help to maintenance this website.
The alternative, as indicated in the diagram, is to make a velocity pressure measurement traverse in the longest available duct run of each branch. This includes pressure losses in ducts, duct fittings, and other system components. This duct should be of a size and shape to fit the fan publicatuon, a minimum publucation 2 equivalent diameters long and equipped with a bell shaped or flared fitting at its inlet.
Before proceeding with the test, it is essential that all system dampers be fixed in the positions agreed upon by all interested parties as being applicable for the installation.
Portions of the procedures are typical for all fan-system wmca. On occasion, an undesirable traverse plane location is unavoidable, or each of a limited number of prospective locations lacks one or more desirable qualities. If, in addition to the losses being negligible there are no changes in the areas between the measurement planes and the respective planes of interest, then the equations are further reduced to: In situations such as this example, the air may be discharging from the ventilator into a region in which the atmospheric pressure is somewhat different from that to which all other pressure measurements are referred.
In instances in which a cooling coil is located between a velocity pressure traverse plane and the fan, as in pulbication example, the flow of the cooling medium should be stopped or its temperature raised to a level sufficient to prevent condensation on the cooling coil, otherwise the moisture condensed will not be properly taken into account in the determination of fan air flow rate.
AMCA Publication R – Free Download PDF
In order to calculate the value of SEF2, it is necessary to measure the outlet area of the fan, A2. Drive loss is defined as follows: Normally, velocities encountered in the field test situations are well in excess of fpm. Select a manometer that will provide an acceptable degree of accuracy; publiaction the range, slope, quality, scale graduations, indicating fluid of the instrument and publicatkon range of the velocity pressures to be measured.
The basis for calculations is described in Section This is an air conditioning unit which has been assembled amcaa the installation site. C Proof of Performance Test – A test in response to a complaint to demonstrate that the fan is meeting the specified performance requirement. Two equations can be used in estimating the motor power output.