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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A location for Plane 3 measurements may be obtained by installing ducts on each silencer inlet, as shown in the diagram.
The alternative is to determine the total flow rate and since the fans and their operating speeds are alike, assume that each fan delivers a flow rate proportional to its actual speed.
The performance ratings for a fan that includes inlet box dampers, variable inlet vanes or outlet dampers cover operation of the fan with these items in the publivation open positions. Also, the temperatures of the heating coils must be kept constant throughout the test period. Reading resolution uncertainties exceed normally acceptable values at velocity pressures less than 0.
In general, the qualifications for a plane well suited for the measurement of static pressure are the same as those for the measurement of velocity pressure, as indicated in Section 9. As shown in the diagram, these planes are located shortly downstream of the inlets and outlets of the fans, which are the planes of interest.
For Plane 3 conditions of: 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.
The graph serves as a reasonable guide in evaluating belt drive losses. Before performing any field test, it is strongly recommended that the following AMCA publications be carefully reviewed: In addition, when the loss through a damper must be calculated, it is essential that the damper blades be fixed in their full open positions during the test since this is the condition on which the damper pressure loss ratings are based.
For rectangular ducts with cross-sectional areas of 24 square feet and less, the recommended minimum number is 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: Static pressure at the fan inlet, Ps1, is derived as follows: These velocity pressure and static pressure measurements are susceptible to error due to the turbulence existing in the region of the fan outlet.
Hole depth shall not be less than the hole diameter. Performance ratings for fans with inlet vanes cover operation with the inlet vanes in their full open position.
AMCA Publication 203-90 (R2007), “Field Performance Measurement of Fan…
This fan, as supplied and rated by the manufacturer, includes the inlet box dampers and the inlet boxes, but does not include the outlet damper. Measure the area of traverse plane, A3, which is located at the tip of the Pitot-static tube. Each of the fans, as supplied and rated by the manufacturer, includes an outlet damper. This pressure value must then be corrected to the test site elevation.
Use a sling psychrometer to obtain dry and wet-bulb air temperature measurements at the fan inlet for free inlet fans. Procedures for the traverse are described in Section 9.
The fan performance ratings are based on operation with the fan outlet ducted. The area of the fan inlets: Ps3 is determined by averaging the static pressure measurements made in the same traverse. The fan flow rate is the volume flow 20390 at the fan inlet density. Hg Use the modified Apjohn equation for partial vapor pressure and the density equation based on perfect gas relationships, both of which are described in Annex M, and the data in Figure N. This fan, as supplied and rated by the manufacturer, does not include the backdraft damper.
Determine the test value of barometric pressure by averaging measurements made at the beginning and end of publicahion test period.
AMCA Publication R – Free Download PDF
Since the flow at a traverse plane is never strictly steady, the velocity pressure measurements indicated by the publicatoin will fluctuate. The velocity pressure at the traverse plane is the root mean square of the velocity pressure measurements made in a traverse of the plane. In instances in which a cooling coil is located between a velocity pressure traverse plane and the fan, as in this example, the flow of upblication 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 pub,ication the determination of fan air flow rate.
The variable inlet vanes are considered part of the fan. Determine pb for the general vicinity of the fan.