Standard and ANSI/ASHRAE Standard 51, except as modified by Units shall be tested in accordance with ANSI/AMCA Standard /ANSI/ASHRAE. Standard — Laboratory Methods of Testing Fans for Aerodynamic Performance Rating (ANSI/AMCA Standard ) (ANSI/ASHRAE Approved). and Air-Conditioning Engineers (ASHRAE) approved ANSI/AMCA Standard ANSI/ASHRAE Standard , Laboratory Methods of Testing Fans for.
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The power required to drive the fan and any elements in the drive train that are considered a part of the fan. An inlet duct used to provide a measurement station shall not be more than If a portion of the internal energy is converted into kinetic energy, the static temperature is decreased accordingly. This requires some backflow to supply the air to mix at the jet boundaries. The nozzle throat dimension L shall be either 0.
A properly performed laboratory traverse is assumed to have equal accuracy: Close the control valve. 5-07
Groups approve laboratory methods for testing fans.
Instruments shall be set up, calibrated, and read by qualified personnel trained to minimize errors. An acceptable alternative is the use of a nozzle 51-7 a throat tap in which case the throat tap located as shown in Figure 4 shall be used in place of the downstream pressure tap shown in the figure for the setup and the piezometer for each flow nozzle shall be connected to its own indicator.
On the inlet duct setup, ts1 is equal to td3 and Pt1 51-7 be considered equal to Pt3 for fan air density calculations. AmazonGlobal Ship Orders Internationally. The specification permitting an uncertainty based on the maximum observed test reading 5107 the test leads to combined relative uncertainties in both fan pressure and fan airflow rate that are higher at low values of the fan pressure or fan airflow rate than at high values of those test results.
Danos Rad Ganesh Paul R. The point of operation where the fan static pressure is zero.
Groups approve laboratory methods for testing fans.
K pc 5 3 Therefore: It may be desirable to convert all test points to a nominal density, a constant rotational speed, or both.
The adjacent arcs, as well as the last arc, shall smoothly meet and blend with the asnrae throat. This includes the ratios of the magnitudes of corresponding velocities of the air and corresponding peripheral velocities of the impeller. It emphasizes the fact that the fan laws can be applied only if the points of operation are similarly situated for the two fans being compared.
There is some average airflow rate which is proportional to peripheral speed and flow area. These formulae use absolute pressure ratios in inches of water.
When making fan law conversions, fan speed has a first power effect on airflow rate. A total pressure tube is considered a primary instrument and need not be calibrated provided if it is maintained in a condition conforming to this standard. An inlet chamber Figure 13, 14 or 15 shall have a cross-sectional area at least five times ashgae fan inlet ahsrae. For setups using nozzles, the nozzle diameters shall be recorded.
The Reynolds Number, Re, based on nozzle exit diameter D6 in meters ftshall be calculated from: The temperature that exists by virtue of the internal energy of the air. A standardized air path of a controlled geometry used ashgae provide consistent test results between different test configurations. Hg and readable to 34 Pa 0.
The uncertainty increases rapidly near shutoff. Since the air velocity in an inlet chamber is considered uniform due to the settling means employed, a single measurement is representative of the average chamber pressure. The degree of similarity of the performance characteristics will depend on the degree of similarity of the fans and of the airflow through the fans.
Complete dynamic similarity requires that the ratios of all corresponding forces in asbrae two fans be equal.
All joints in the chamber, ducts and other equipment between the fan and the flow measuring plane, including the nozzle ashfae, if applicable, should be designed and maintained to practically eliminate leakage.
Plane x is Plane 4 for duct approach or Plane 5 for chamber approach. These devices shall be free from slip and calibrated.
The specifications regarding accuracy correspond to two standard deviations based on an assumed normal distribution. An example is shown in Annex C. A pre-test uncertainties analysis is not required for each test covered by this standard because it is recognized that most laboratory tests for rating are conducted in facilities where similar tests are repeatedly run.
Additional determinations may be required to define the curve or a portion thereof for a fan that exhibits a dip or other discontinuity. Uncertainties Analysis [10] Informative F. English Choose a language for shopping.