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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Ps4 may be determined by averaging the pressure measurements at each of four static pressure taps or by averaging the static pressure measurements made in a Pitot-static tube traverse of Plane 4.

When the inlet side of the fan is not ducted but is designed to accept a duct, consider installing a short length of inlet duct to provide a suitable traverse plane location. Since the performance ratings for publiction fan section are based on operation without the fan outlet ducted, an SEF does not apply for the unducted position.

Annex K estimating the power output of three phase motors and Annex L estimating belt drive losses were rewritten and adjusted based on new information received from motor and drive manufacturers.

For Plane 2 conditions of: This is done for the purpose of allowing direct comparison of the test results to the design static pressure publicaton.

Failure to release simultaneously may result in manometer fluid being blown from the manometer. This example is no exception. Measure td3 and tw3 near the entrance to the short inlet duct.

The effect of this duct on the system is negligible, but in changing the pattern of the flow of air into the fan inlet, it may affect the performance of the fan slightly.

AMCA Publication R – Free Download PDF

Information as to whether the fan power input ratings include power transmission losses is included in the published performance ratings or is otherwise available from the fan manufacturer. In judging SEF 2, publicxtion rapidly diverging transition fitting downstream of the fan is considered equivalent to no duct at the fan outlet. 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.


This static pressure value is used to determine the density at the traverse plane. Work required to measurements drilling installation of static thermometer wells, etc.

In order to determine the air flow rate, it is necessary to measure the area of the traverse plane. The temperature determination should be representative of the average temperature of the gas stream throughout the plane of interest. Normally, the higher levels of accuracy requirements can be met by using this type of instrument, providing the measurements are oublication up on the scales. The data supplied by the motor manufacturer indicate motor efficiency of Therefore, Ps2 will be calculated based on Ps5 and the assumption that there is no change in total pressure from Plane 2 to Plane 5.

Each of the procedures requires knowledge of the pressure, dry-bulb temperature and wet-bulb temperature of the air. Measure td1 and td2.

Items affecting the system include: 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 publicatjon is normally involved. Where a single traverse plane is used, the calculation of the fan flow rate is: When this possibility exists, it is essential that the static pressure in the region of the discharging air be measured, referred to the same atmospheric pressure as used in all other pressure measurements.

However, due to the turbulence existing in the regions of the outlets of the fans, it is recommended that publicahion pressure taps be used at Planes 1b-2a and 2b. This is due mainly to is high cost and the cost of its installation.

The chart is only intended to indicate the accuracy and suitability of using the above equations for estimating motor power output. In order to account for water vapor which may have been added to the air as a result of evaporation of moisture previously condensed on the coil, the wet-bulb temperature at Plane 3 was measured.

AMCA Publication 203 R2007

The static pressure at this location is difficult to measure accurately with a Pitot-static tube due to the existence of turbulence and localized high velocities. In many cases, accuracy level requirements will permit the use of a clip-on type ammeter-voltmeter. 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 pubpication velocity pressure conversion and include any associated pressure loss.


The static pressure measurements involved must be referred to the same atmospheric pressure and made at locations sufficiently distant from the fan inlet and outlet so as to be unaffected by the velocity of the air entering and leaving the fan.

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

Hg at Plane 1, calculated as follows: Normally, velocities encountered in the field test situations are well in excess of fpm. 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.

Determine Ps1 by averaging the pressure measurements at each of four static pressure taps in the collar connection at the fan inlet. At this point, the static pressure is zero, and 203-900 R the velocity pressure in still air is zero. Each velocity pressure measurement should be mentally averaged on a time-weighted basis.

Determine fan power input by using the motor power output and, where applicable, the power transmission loss. Two equations can be used in estimating the motor power output.

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. These conversion equations do not account for the effect of the compressibility of the gas stream. The effect created by this fitting is considered to be equivalent to the effect created by having no duct amc the fan outlet. In this example, Ps2 is considered to be equal to Ps5. The fan power input is the motor power output minus the power transmission loss, where applicable.

This blade angle should be agreed upon by all interested parties.