NORMA - ANSI-AMCA Standard 250-05 Laboratory Methods of Testing Jet Tunnel Fans for Performance

ANSI/AMCA Standard 250-05 Laboratory Methods of Testing Jet Tunnel Fans for Performance

An American National Standard Approved by ANSI on August 31, 2005

AIR MOVEMENT AND CONTROL

ASSOCIATION INTERNATIONAL, INC. The International Authority on Air System Components

ANSI/AMCA STANDARD 250-05

Laboratory Methods of Testing Jet Tunnel Fans for Performance

Air Movement and Control Association International, Inc. 30 West University Drive Arlington Heights, IL 60004-1893

© 2007 by Air Movement and Control Association International, Inc. All rights reserved. Reproduction or translation of any part of this work beyond that permitted by Sections 107 and 108 of the United States Copyright Act without the permission of the copyright owner is unlawful. Requests for permission or further information should be addressed to the Chief Staff Executive, Air Movement and Control Association International, Inc. at 30 West University Drive, Arlington Heights, IL 60004-1893 U.S.A.

Authority ANSI/AMCA Standard 250-05 was adopted by the membership of the Air Movement and Control Association International, Inc. on 14 January 2001. It was approved by ANSI as an American National Standard on 31 August 2005.

AMCA 250 Review Committee Tony Quinn, Chair

Woods Division, American Fan Co.

Roger Lichtenwald

American Warming & Ventilating

Ralph Susey

New Philadelphia Fan Company

John Knapp

Ruskin Manufacturing

Mike Wiltfong

Ruskin Manufacturing

Robert Smith

TLT-Babcock, Inc.

Paul R. Saxon

AMCA Staff

Foreword This standard was developed in response to the need for a standard method of testing jet fans, sometimes called impulse fans, which have seen increasing use in the United States. The test procedures outlined in this standard are in harmony with those found in ISO 13350. It is believed that ANSI/AMCA 250 will be of great benefit to purchaser and manufacturer alike.

Introduction The need for adequate ventilation to maintain or improve the quality of air in vehicular tunnels is self-evident. One means of achieving such ventilation is through the use of fans located above the traffic pattern and spaced at intervals along the length of a tunnel. These fans produce a jet (or impulse) of air that induces airflow through the entire tunnel. Secondarily, this means of achieving airflow is also useful in smoke evacuation.

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. However, AMCA does not guarantee, certify or assure the safety or performance of any products, components or systems tested, designed, installed or operated in accordance with AMCA standards or that any tests conducted under its standards will be non-hazardous or free from risk.

Objections to AMCA Standards and Certifications Programs Air Movement and Control Association International, Inc. will consider and decide all written complaints regarding its standards, certification programs, or interpretations thereof. For information on procedures for submitting and handling complaints, write to: Air Movement and Control Association International 30 West University Drive Arlington Heights, IL 60004-1893 U.S.A. or AMCA International, Incorporated c/o Federation of Environmental Trade Associations 2 Waltham Court, Milley Lane, Hare Hatch Reading, Berkshire RG10 9TH United Kingdom

TABLE OF CONTENTS

1.

Scope

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

2.

Normative References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

3.

Definitions and Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 3.1 Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 3.2 Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

4.

Characteristics to be Measured . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 4.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 4.2 Volume airflow rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 4.3 Thrust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 4.4 Input power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 4.5 Sound power level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 4.6 Vibration velocity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

5.

Instrumentation and Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 5.1 Volume airflow rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 5.2 Thrust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 5.3 Input power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 5.4 Impeller rotational speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 5.5 Sound level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 5.6 Vibration velocity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

6.

Determination of Airflow Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 6.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 6.2 Direct connected airflow measuring device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 6.3 Upstream chamber method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 6.4 Upstream pitot traverse method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

7.

Determination of Thrust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 7.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

7.2 Suspended configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 7.3 Supported configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 7.4 Test procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 7.5 Test enclosure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 8.

Determination of Sound Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 8.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 8.2 Test arrangement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 8.3 Enclosure suitability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 8.4 Measurement procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

9.

Determination of Vibration Velocity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 9.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 9.2 Test arrangement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 9.3 Test procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 9.4 Acceptance vibration velocity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

10. Presentation of Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 10.1 Product description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 10.2 Product performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 11. Tolerances and Conversion Rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9 11.1 Tolerances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9 11.2 Conversion rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9 Annex A.

Illustration of Reference Sound Source (Normative) . . . . . . . . . . . . . . . . . . . . . . . . . . . .22

Annex B.

Combination of Sound Pressure Levels (Normative) . . . . . . . . . . . . . . . . . . . . . . . . . . . .23

Annex C.

Conversion Rules (Normative) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24

Annex D.

Informative References (Informative) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25

AMCA INTERNATIONAL, INC.

ANSI/AMCA 250-05

Laboratory Methods of Testing Jet Tunnel Fans for Performance

ANSI/AMCA 210-99 Laboratory Methods of Testing Fans for Aerodynamic Performance Rating, Air Movement and Control Association International, Arlington Heights, IL U.S.A., 2000

1. Scope

ANSI/NEMA MG 1-2003, Motors and Generators, National Electrical Manufacturers Association, Rosslyn, VA, USA.

This standard deals with the determination of those technical characteristics needed to describe all aspects of the performance of jet tunnel fans. It does not cover those fans designed for ducted applications nor those designed solely for air circulation, e.g., ceiling fans and table fans.

ISO 5801:1997(E), Industrial Fans - Performance Testing Using Standardized Airways, International Organization for Standardization, Geneva, Switzerland, 1996

3. Definitions and Symbols The test procedures described in this standard relate to laboratory conditions. The measurement of performance under in-situ conditions is not included. The parties to a test for guarantee purposes may agree on exceptions to this standard in writing prior to the test. However, only tests that do not violate any mandatory requirements of this standard shall be designated as tests conducted in accordance with this standard.

2. Normative References The following standards contain provisions that, through specific reference in this text, constitute provisions of this American National Standard. At the time of publication the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this American National Standard are encouraged to investigate the possibility of applying the most recent editions of the standards listed below. AMCA 300-96, Reverberant Room Method for Sound Testing of Fans, Air Movement and Control Association International, Inc., Arlington Heights, IL, USA. ANSI S2.19-1999 (R2004), Mechanical Vibrations Balance Quality Requirements of Rigid Motors - Part 1: Determination of Possible Unbalance, Including Marine Applications, American National Standards Institute, New York, NY, USA. ANSI/AMCA 204-96 Balance Quality and Vibration Levels for Fans, Air Movement and Control Association International, Arlington Heights, IL U.S.A., 1998

3.1 Definitions For the purposes of this standard, the following definitions apply: 3.1.1 Air. A mixture of various gases forming the earth’s atmosphere and commonly used to denote any gaseous medium measured, moved or controlled in a HVAC system. 3.1.2 Standard air. Air with a density of 1.2 kg/m3 (0.75 lbm/ft3), a specific heat ratio of 1.4, a viscosity of 1.819 × 10-5 Pa•s (1.222 × 10-5 lbm/ft-sec) and an absolute pressure of 101.325 kPa (408.0 in. wg). Air at 20°C (68°F), 50% relative humidity, and 101.325 kPa (29.92 in. Hg) has these properties, approximately. 3.1.3 Absolute pressure. Pressure above a perfect vacuum; the sum of gauge pressure and atmospheric pressure. The value is always positive. 3.1.4 Barometric pressure. The absolute pressure exerted by the atmosphere at a location of measurement. 3.1.5 Dry-bulb temperature. Air temperature measured by a temperature-sensing device without modifications to compensate for the effect of humidity. 3.1.6 Static pressure at a point. That portion of air pressure that exists by virtue of the degree of compression only. If expressed as gauge pressure, it may be negative or positive. 3.1.7 Volume airflow rate. The volume of air that passes through a given area in unit time. 1

ANSI/AMCA 250-05 Actual Cubic Meters per Second (actual m3/s), or Actual Cubic Feet per Minute (acfm): The actual volume airflow rate at any point in an air system, at the existing density at the plane passing through the point of measurement. 3.1.8 Average air velocity. The volume airflow at a plane divided by the cross-sectional area of that plane. 3.1.9 Fan dynamic pressure. The effective dynamic pressure at the fan outlet calculated from the effective fan outlet velocity and the inlet density. It is representative of the dynamic component of the fan output. The effective dynamic pressure varies from the average dynamic pressure as the former excludes the energy flux due to departures from the uniform axial velocity distribution.

4) Where the motor is on the upstream side, Figure 1C is applied to the impeller hub rather than the motor - as illustrated. 3.1.11 Effective fan outlet velocity. Calculated air velocity based on fan thrust, inlet air density and fan outlet area. 3.1.12 Fan outlet velocity. Average velocity of air emerging from an outlet measured in the plane of the outlet. 3.1.13 Air power. Power output which is the product of the inlet volume airflow and the fan dynamic pressure. 3.1.14 Impeller power. The mechanical power supplied to the fan impeller.

3.1.10 Fan outlet area. The gross inside area measured at the plane(s) of the outlet openings.

3.1.15 Motor input power. The electrical power supplied to the terminals of an electric motor drive.

1) If the silencer centerbody reaches the outlet plane of the fan then the "fan outlet area" is defined as the annulus area at the fan outlet plane as shown in Figure 1A.

3.1.16 Rotational speed. The rotational speed of an impeller. If a fan has more than one impeller, fan speeds are the rotative speeds of each impeller.

2) If the fan has a silencer without centerbody, Figure 1B, the outlet area will be close to the cross-sectional area inside the silencer in order to clear any exit bellmouth form. 3) For a fan without a silencer, Figure 1C, the outlet area will approach the annulus area between the casing and the motor but with some increase, as defined in the diagram, for the distance between the motor and the outlet.

3.1.17 Mean blade speed. The tangential velocity at 1/√2 (or 0.7071) times the blade height between impeller hub and tip. 3.1.18 Thrust. The force exerted by a fan in a specific direction. 3.1.19 Fan efficiency. Ratio of the air power to the impeller power, expressed as a percentage. 3.1.20 Overall efficiency. Ratio of the air power to the motor input power, expressed as a percentage.

Figure 1 - Effective Fan Outlet Area 2

ANSI/AMCA 250-05 3.1.21 Thrust/power ratio. Ratio of the thrust to impeller power. Note: An alternative definition of thrust efficiency is defined as thrust divided by the motor input power. This results in a lower figure as the motor losses are also included. 3.1.22 Fan. A device that utilizes a power driven rotating impeller for moving air or gases. The internal energy (enthalpy) increase imparted by a fan to a gas does not exceed 25 kJ/kg (10.75 BTU/lbm). 3.1.23 Jet tunnel fan. A fan used for producing a jet of air in a space and unconnected to any ducting. Typical function is to add momentum to the air within a duct or tunnel. 3.1.24 Fan guard. A screen or other device to prevent ingestion of objects at the inlet or outlet of a fan.

3.1.32 Shall and should. In AMCA standards, the word “shall” is understood to be normative; the word “should” as advisory.

3.2 Symbols See Table 1 for a list of symbols.

4. Characteristics to be Measured 4.1 General In order for a jet-type tunnel fan to be correctly applied and give satisfactory performance and reliability in service, it is necessary to determine a number of technical performance characteristics in addition to knowing the more obvious mechanical features such as weight and overall installation dimensions.

4.2 Volume airflow rate Note: Guards can have a marked effect on the thrust performance and sound level. Where they are specified, it shall be made quite clear between the supplier and his customer whether the performance includes the effect of the guards. 3.1.25 Chamber. An airway in which the air velocity is small compared to that at the fan inlet or outlet. 3.1.26 Test enclosure. A room, or other space used for the purposes of testing. 3.1.27 Sound power level, Lw. Acoustic power rating from a sound source measured in decibels and equal to 10 times the logarithm (base 10) of the acoustic power in watts with reference to 10 ×10-12 watts. 3.1.28 Sound pressure level, Lp. The acoustic pressure at a point in space where the microphone or listener’s ear is situated. It is defined as 20 times the logarithm (base 10) of the sound pressure fluctuation with reference to 20 μPa. 3.1.29 Frequency range of interest. The frequency range including the octave bands with center frequencies between 63 Hz and 8 kHz, and the onethird octave bands with center frequencies between 50 Hz and 10 kHz. 3.1.30 Impeller balance grade. The impeller balance specification in accordance with the method detailed in ANSI S2.19 and to the grade specified in ANSI/AMCA 204.

Volume airflow rate need only be measured if required for contractual reasons. The effective outlet velocity, not the volumetric airflow rate, is used to evaluate the optimum number, size and spacing of jet fans in a tunnel. Higher velocities reduce thrust efficiency but the effect of tunnel air velocity on thrust is reduced.

4.3 Thrust Friction on the tunnel walls, inlet and outlet losses and, sometimes, traffic drag combined with gradients and wind effects at tunnel portals, result in a pressure drop through the tunnel. The pressure drop is matched by the sum of the pressure increases by the jet fans due to the momentum transfer between the fan discharge airflow and the airflow in the tunnel. As it is impossible to measure the momentum of the fan discharge airflow, and the rate of change of momentum is equal and opposite to the thrust, thrust is measured instead. The process of providing additional momentum to the tunnel air helps to maintain air quality.

4.4 Input power In order to calculate the cost of operating the jet tunnel fans (there may be a substantial number) in a tunnel, it is necessary to know the input power to the fan motor.

4.5 Sound power level 3.1.31 Fan vibration velocity. The filtered vibration velocity in the frequency range 10 Hz through 10 kHz measured in accordance with this standard.

Sound levels, usually at inlet and outlet, are established in order to ensure that the jet fan and 3

ANSI/AMCA 250-05

Table 1 - Symbols SYMBOL

DESCRIPTION

SI Units

Aeff D d3 ΔP G Lpb Lp(m)

Area of fan inlet or outlet Fan diameter Length of upstream chamber side Differential pressure across a flow measuring device Impeller balance grade ANSI/AMCA 204 Background sound pressure level Recorded sound power level of fan and room background as measured over the normal mic. path Recorded sound pressure level of RSS and room background as measured over the normal mic. path Sound power level, re 1 pW Sound power level of the RSS Sound power level (forward) Sound power level (reverse) Sound pressure level Impeller rotational speed Atmospheric pressure in test enclosure Fan dynamic pressure Motor input power Fan air power Impeller power Mass airflow Volume airflow Thrust/power ratio Atmospheric temperature in test enclosure (dry-bulb) Calculated thrust Measured thrust Mean blade speed (see definition 3.1.17) Mean through airflow velocity in a tunnel at a specified section Effective fan outlet air velocity Fan vibration velocity at upstream measuring position - rms value Fan vibration velocity at downstream measuring position - rms value Fan efficiency Overall efficiency Inlet air density taken as equal to the air density in the test enclosure

m2 ft2 mm in. m ft Pa in. wg dimensionless dB dB dB dB

Lp(r) Lw Lw(r) Lw1 Lw2 Lp N Pa pd PE PF PR qm qv rT ta Tc Tm um vt veff V1 V2

ηr ηe ρa

4

I-P Units

dB

dB

dB dB dB dB dB rpm Pa Pa W W W kg/s m3/s N/kW °C N N m/s m/s

dB dB dB dB dB rpm in. Hg in. wg hp hp hp lbm/s cfm lbf/Hp °F lbf lbf ft/min ft/min

m/s mm/s

ft/min in./s

mm/s

in./s

% % kg/m3

% % lbm/ft3

ANSI/AMCA 250-05 silencer combination is optimized to match the tunnel sound level requirements.

4.6 Vibration velocity For reasons of safety, reliability and maintainability, it is essential that a realistic vibration velocity is specified and recorded on tunnel fans. These shall be measured at the support points in accordance with ANSI/AMCA 204.

5. Instrumentation and Measurements

requirements given in ANSI/AMCA 300.

5.6 Vibration velocity Instruments to measure rms vibration velocity shall be used to record fan vibration velocities. These shall be in accordance with ANSI/AMCA 204.

6. Determination of Airflow Rate 6.1 General

5.1.1 Instruments for the measurement of pressure. Manometers for the measurement of differential pressure, and barometers for the measurement of atmospheric pressure in the test enclosure, shall comply with the requirements of ANSI/AMCA 210 or ISO 5801.

There are three methods available for the determination of airflow rate. The most convenient uses a venturi nozzle or conical inlet, connected upstream of the jet tunnel fan, as the airflow measuring device. The second makes use of an upstream chamber test configuration. In this case a booster fan forms part of the test setup enabling the fan's operating point to be simulated correctly. The third method uses a Pitot traverse at the jet fan inlet.

5.1.2 Instruments for the measurement of temperature. Thermometer(s) shall comply with the requirements of ANSI/AMCA 210 (ISO 5801).

It should be noted that the airflow through a jet fan has no direct relationship with the airflow through a tunnel.

5.2 Thrust

6.2 Direct connected airflow measuring device

5.2.1 Force balance systems. By the use of calibrated weights, force balance systems shall permit the determination of force or thrust with an allowable uncertainty of no greater than ±1%.

The airflow measuring device shall be connected by suitable means to the fan inlet as illustrated on Figure 2. Details of the venturi nozzle shall comply with ANSI/AMCA 210, Figure 4. Details of the conical inlet shall comply with ISO 5801, Figure 21. For the purpose of airflow rate determination in accordance with this standard, an anti-swirl device is not required.

5.1 Volume airflow rate

5.2.2 Force transducers. By the use of calibrated weights, force transducers shall permit the determination of thrust with an allowable uncertainty no greater than ±1%. 5.2.3 Dimensions and areas. The measurement of dimensions and the determination of areas shall be in accordance with ANSI/AMCA 210 or ISO 5801.

5.3 Input power Determination of the power input to the electric motor or to the impeller shall be carried out in accordance with ANSI/AMCA 210 or ISO 5801.

Airflow rate for the venturi nozzle is calculated in accordance with ANSI/AMCA 210, Section 8. Airflow rate for a conical inlet is calculated in accordance with ISO 5801 clause 24.

6.3 Upstream chamber method Installation of the fan in the chamber is illustrated in Figure 3. This arrangement simulates a free inlet, free outlet installation. Upstream sections of the test assembly shall be in accordance with ANSI/AMCA 210 or ISO 5801.

5.4 Impeller rotational speed

5.5 Sound level

A venturi nozzle, quadrant inlet nozzle, or conical inlet can be used to determine airflow rate in accordance with ISO 5801, clauses 22, 24, and 25. Multiple nozzles may be used in accordance with ANSI/AMCA 210, Figure 14 or 15.

The sound level measuring system including microphones, windshields, cables, amplifiers and frequency analyzer shall be in accordance with the

In order to establish the correct operating point, with no adverse pressure across the fan, a test system booster fan shall be controlled such that:

Impeller rotational speed shall be determined in accordance with ANSI/AMCA 210 or ISO 5801.

5

ANSI/AMCA 250-05 Ps3 = Ps2 = 0 Where Ps3 is the static pressure in the fan chamber and Ps2 is the static pressure at the fan outlet. If it is not possible to control the booster accurately, it may be necessary to measure the airflow at more than one operating point.

6.4 Upstream pitot traverse method For this method, the airflow rate should be determined in accordance with ANSI/AMCA 210 (ISO 5801).

7. Determination of Thrust 7.1 General There are two basic configurations available for the determination of fan thrust; suspended configuration and supported configuration. In addition to the need to measure force accurately, the first method requires that the suspension elements be kept precisely vertical and parallel with a vertical plane(s) passing through the fan axis, while the second method requires accurate construction and leveling of the support assembly. In either case, thrust shall be determined by the use of calibrated weights, spring balance or force transducer.

7.2 Suspended configuration Figure 4 shows a typical arrangement of a suspended configuration. The fan is suspended from a framework or gantry with the suspension elements at least one fan diameter long. The frame should allow free airflow, particularly at the fan inlet. Below or surrounding the fan, is a rigid framework which serves a threefold function: a) provides the reference point for the fan test assembly under static conditions b) provides support for a pulley system to take calibrated weights or a spring balance c) provides a reaction point for a force transducer Under operating conditions, the measuring system loads are adjusted to return the fan to the static position, to within ±2 mm (0.08 inches), and thus ensure that the suspension elements are precisely vertical. The thrust can then be measured directly. Note: It should be noted that with the thrust/weight ratios typical of a jet tunnel fan, it is doubtful whether 6

the desired accuracy of thrust measurement can be attained by other means such as measuring the angle of the suspension elements from the vertical or the change in height between the fan switched off and operational, and calculating the thrust.

7.3 Supported configuration Arrangements of the supported configuration are shown on Figures 5A, 5B and 5C. The fan is supported, via low friction linear bearings or leaf springs, on a rigid framework. The fan, to an extent limited by stops, is free to move in either direction. Before commencing any tests, the assembly shall be carefully leveled in each direction, such that the same effort is required to move the assembly along the axis of the fan, in either direction. Under operating conditions, the measuring system loads are adjusted to ensure the movement is not restrained by the stops. Thrust can then be measured directly. In the case of the use of a force transducer, the fan can be allowed to abut the sensor directly.

7.4 Test procedures To ensure that thrust is measured to the required accuracy, steps shall be taken to minimize errors due to setting up/rigging the test arrangement. Though calibrated weights or spring balances are specified, if a spring balance is employed to register thrust and it is supported via a pulley, its weight must be accurately known and added to the measured thrust. If a force transducer is being used to measure thrust, it shall be calibrated. For example, by using a pulley and weight system, before each series of tests. Where the supported method is being used, precautions shall be taken to ensure that the force required to move the fan in either direction is the same and that the assembly is therefore level. Thrust readings shall be recorded when both the thrust and power input readings have stabilized, or at least 10 minutes after start up.

7.5 Test enclosure Figure 6 shows the clearances required in the test enclosure.

8. Determination of Sound Level 8.1 General Sound levels are measured by the semi-reverberant method. The method is essentially practical, and

ANSI/AMCA 250-05 apart from the sound measuring instrumentation, only a suitable enclosure and a calibrated Reference Sound Source are required. Since the fan has only one operating point (at zero resistance), there are no complications that could arise from the noise generated by the "loading means." Similarly, since only open inlet or open outlet sound levels are required, anechoic terminators are unnecessary.

8.4 Measurement procedure Before conducting actual measurements, and with both the test fan and the RSS inoperative, the average sound pressure level, in each octave band shall be determined along the primary microphone path. This shall be at least 6 dB in each octave band lower than the average sound pressure level measured from either the fan sound source or the RSS. Corrections for background sound pressure level should be made as recommended in Annex B.

8.2 Test arrangement Positioning of the fan, the calibrated Reference Sound Source and the microphone paths are shown in Figure 7.

8.3 Enclosure suitability A primary microphone path shall be located on an arc or straight line of length between 1.5 and 3 m (5 and 10 ft) at a distance of not less than 2 m (79 in.) from any major reflecting surface. No point on this path shall be within 45° of the centerline of the fan sound source, and the path itself shall not be within 10° of being parallel to any room surface and shall be located towards a corner of the room. The path shall be located so that the microphone is not subjected to an air velocity in excess of 2 m/s (6.5 ft/sec); refer to Figure 7. A Reference Sound Source (RSS) shall be located such that its acoustic center is the same distance from the mid point of the microphone path as the center of the fan sound source but not nearer to the latter, or any major reflecting surface, than 1 m (3.25 ft). The RSS shall meet the requirements of ANSI/AMCA 300 (also see Annex A). The RSS shall be run at a speed within 2% of the speed at which it was calibrated. With the RSS operating, but with the test fan impeller stationary, readings of sound pressure level shall be made in each octave band along the primary microphone path and the average value along the path estimated. A secondary microphone path similar to the primary microphone and of the same length shall be established at a position half way between the RSS and the mid point of the original microphone path, and at right angles to the line joining them. The average sound pressure level along this path in each octave band shall not be more than 3 dB above the average for the primary microphone path, both values being corrected for background sound pressure level in accordance with Annex B.

With the RSS in operation, but with the test fan impeller stationary, readings of sound pressure shall be made in each octave band along the primary microphone path, and the average sound pressure level, Lp(r), shall be determined. With the RSS removed and the test fan running, readings of sound pressure level shall be made and the average sound pressure level Lp(m), in each octave band, determined. The values of Lp(r) and Lp(m), are corrected, where necessary, as recommended in Annex B, and the open inlet or open outlet sound power level of the fan, LW calculated, in each octave band, from: LW = Lp(m) - Lp(r) + LW(r) Where LW and LW(r) are in dB, and LW(r) is the sound power level of the RSS. For fans designed to provide thrust in one direction only, the inlet sound power level, LW1, shall be quoted. Where the fan is designed to operate in either direction, LW1 shall be quoted for the forward direction together with a correction to arrive at the value of LW2 for reverse operation.

9. Determination of Vibration Velocity 9.1 General Because the jet tunnel fan, for practical purposes, has only one operating point as far as standard laboratory tests are concerned, the arrangements for testing vibration velocity can be simplified.

9.2 Test arrangement Figure 8 illustrates the arrangement that shall be used for measuring vibration velocity. Tests shall be taken with the same jet tunnel fan configuration as will be supplied to the customer. In other words, upstream and/or downstream silencers should be fitted as appropriate. Where vibration isolators are specified and vibration levels are required to be measured, the minimum static deflections given in Table 9.1 shall be used for the purpose of the measurement. 7

ANSI/AMCA 250-05 Table 9.1 - Minimum Static Deflections

Impeller speed, rpm

Minimum Static Deflection

850 - 1000

15 mm (0.6 in.)

1100 - 1800

8 mm (0.3 in.)

2800 & above

2.5 mm (0.1 in.)

Unless agreed otherwise between client and supplier, the impeller of the fan unit shall be balanced to grade G2.5 of ANSI S2.19 (ISO 1940) as recommended in ANSI/AMCA 204 for jet tunnel fans. The electric motor shall be supplied to the vibration level for the motor frame size in accordance with NEMA MG-1, Part 7 (IEC 34).

d) Motor output rating and frame size e) Electrical supply data f) High temperature operating capability g) Overall dimensions h) Mounting dimensions i) Fan assembly weight j) Accessories, e.g., guards, vibration isolators k) Condition monitoring equipment.

9.3 Test procedure

10.2 Product performance

Unless agreed otherwise between client and supplier, vibration velocities shall be measured in accordance with ANSI/AMCA 204. Owing to the axial symmetry of the jet fan and the simple two bearing assembly, it is only necessary to record the vibration in the vertical direction.

The performance of the product described in Section 10.1, shall include the information described in the following points a through e as a minimum. By agreement with the client, the data may be provided for "forward" and "reverse" operation.

Two readings of vibration shall be recorded, one on the upstream side and one on the downstream side mounting bracket. The measured levels shall be: vertical vibration velocity in mm/s, r.m.s (in./s, r.m.s.) filtered to impeller rotational speed.

It shall always be made clear which accessories were fitted when the performance tests were undertaken. a) Thrust b) Effective outlet air velocity; see Note 1 c) Motor input power

9.4 Acceptance vibration velocity Table 9.2 - Acceptance Vibration Velocity

d) Maximum open inlet or open outlet sound power level; see Note 2

Mounting Method

e) Maximum upstream and downstream vibration velocity.

Max. mm/s, Max. in./s,

Vibration isolators per Table 1

4.5

Hard Mounted

1.0

0.177 0.039

10. Presentation of Results

Note 1: the effective outlet air velocity veff is used to calculate the correction factor, k, on the thrust due to the mainstream tunnel air velocity, vt, in the tunnel. Where:

10.1 Product description

k = (veff – vt) / veff

The test report shall include a product description which, as a minimum, shall include the following information:

veff can best be defined as:

a) Model reference b) Size of fan

8

c) Impeller rotational speed

v eff =

Tm Aeff × ρa

For the definition of Aeff, fan outlet area, see Section 3.1.10.

ANSI/AMCA 250-05 Note 2: It may be preferred, by prior agreement with the client, to present sound level data in an alternative form. For example, an A-weighted spherical sound pressure level at 10 or 3 m (33 or 10 ft), 45° in free field. Also by agreement with the client it shall be decided whether the sound level is given as a single total figure or in each octave band.

Silencer pod geometry

Note 3: If required for contractual reasons, the airflow rate may be determined by one of the methods given in ANSI/AMCA 210 or ISO 5801.

Blade shape and solidity (number of blades)

11. Tolerances and Conversion Rules

Motor support design

11.1 Tolerances

Motor frame size

The performance quoted is the most probable performance, not the minimum value. The tolerance values apply to jet tunnel fans operating without external resistance and as tested in accordance with this standard.

Blade tip clearance (smoke venting designs)

As shown in Table 11.1, the tolerances are intended to take account of measurement uncertainty and manufacturing variations. When direct test results are not available, refer to Annex C.

11.2 Conversion rules The conversion rules recommended in Annex C apply to fan assemblies with geometric similarity. In the case of jet tunnel fans this means similarity of the following features: Silencer lengths

Silencer bellmouth shape Impeller hub to diameter ratio Impeller spinner profile

Blade setting angle

It is accepted that for practical reasons it is not reasonable for every configuration of fan to be subjected to a direct test. Also, perfect geometric similarity is not always readily achievable. Nonetheless, it is incumbent on the manufacturer to authenticate any conversion rules used. Application of conversion rules shall be limited as follows: when calculating the performance of another fan from a direct test and allowing for some departure from geometric similarity: Fan size: ± one R20 step (per AMCA 99-0098-00) Impeller speed = (test speed) × 1.3 Or (test speed) / 1.3

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Table 11.1 - Tolerances Measured parameter

Measurement uncertainty

Manufacturing variation

Notes

Thrust

±5%

±1%

1

Effective outlet velocity

±10%

±2%

1, 2

Input power

±1.5%

±2.5%

-

Sound level

-

±2%

3

Note 1: It should be noted that while thrust is measured, the effective outlet air velocity is calculated from the thrust, using air density and a conventionalized outlet area. Note 2: The relatively large uncertainty of the effective outlet air velocity will, in most cases, have little practical importance in relation to the thrust to be installed in the tunnel as it only concerns a secondary correction factor. Note 3: Uncertainty of measurement of broad band sound levels can be taken as 3 dB for the 125 Hz, 250 Hz and 8000 Hz bands; 2 dB for 500 Hz band; and 1.5 dB for the 1 kHz and 4000 Hz bands. While uncertainty will be greater than 3 dB for the 63 Hz band no information is available. To allow for manufacturing deviations a further 2 dB should be added.

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Figure 2 - Airflow Measuring Installation (Direct Connected)

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Notes:

Figure 2A - Piezometer Ring Manifolding

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Figure 3 - Airflow Measuring Installation (Upstream Chamber) - Suspended Method

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Figure 3 - Airflow Measuring Installation (Upstream Chamber) - Suspended Method

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Figure 4 - Thrust Measuring Layout - Suspended Method with Adjustable Position Transducer Measuring System

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Thrust Gauge (Measurement in N (lbf)) (Thrust = Gauge reading - weight of gauge in suspension) Note: The fan shall be accurately leveled prior to testing.

Figure 5A - Thrust Measuring Layout - Supported Method with Linear Bearings and Thrust Gauge in Suspension

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Figure 5B - Thrust Measuring Layout - Supported Method with Linear Bearings and Transducer Measuring System

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Figure 5C - Thrust Measuring Layout - Supported Method with Leaf Springs and Load Cell

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Figure 6 - Thrust Measuring Enclosure

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Figure 7 - Semi-Reverberant Enclosure

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Figure 8 - Vibration Measuring Positions for Jet Tunnel Fans

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Annex A. Illustration of Reference Sound Source (Normative) If a calibrated reference sound source is not available commercially, then an impeller manufactured in accordance with this illustration and correctly calibrated may be used.

Figure A.1 - Reference Sound Source Impeller

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Annex B. Combination of Sound Pressure Levels (Normative) When the sound pressure level with the fan running exceeds the background sound pressure level with the fan stopped by 10 dB or more, no correction need be applied. When the difference is less than 10 dB, corrections as given below should be applied.

⎛ Lpb ⎞ ⎛ ⎛⎜⎜ Lpm ⎞⎟⎟ ⎜⎜ ⎟⎞ 10 ⎟ ⎝ 10 ⎠ ⎜ Lpc = 10 log10 10 − 10⎝ ⎠ ⎟ ⎜ ⎟ ⎝ ⎠

Table B.1 - Background Correction dB increase in level produced by the fan

dB to be subtracted from the measured value

3

3

4-5

2

6-9

1

10 or more

0

When the increase is less than 3 dB, measurements in general cease to have any significance.

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Annex C. Conversion Rules (Normative) C.1 Performance coefficients The following conversion rules, subject to agreement between the supplier and client, shall be used when deriving the performance of a fan that has not been directly tested. Conversion is, in the main, based on the use of dimensionless coefficients. A different procedure is used for sound levels.

Flow Coefficient:

ϕ = qv / (Aa × u) Where: Aa = impeller annulus area. u = impeller tip speed = π × Dr × N

Thrust Coefficient:

Θ=

2Tc Aa × ρ × u 2

(see Note 2 below).

Power Coefficient:

Φ =

2PR Aa × ρ × u 3

Note 1: Tc shall not be calculated from ρqvv. Gross errors may arise from using this formula, principally due to the non-uniformity of air velocity at the fan outlet and a lack of certainty as to the effective outlet area of the fan. Note 2: The above performance coefficients differ from those in ISO 5801 but have been found to give good correlation of test data for axial flow jet fans. Sound Power Level: Total sound power levels shall be converted according to the following relationship. (See Note below). Lwc = Lwt + 50 log10 (Nc / Nt) + 70 log10 (dc / dt) Where: D = nominal fan diameter N = impeller rotational speed suffix c = calculated suffix t = test. Note: If the above relationship is used to calculate octave band sound levels, then suitable adjustments must be made if the blade passing frequency changes to a different octave band than that of the test fan.

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ANSI/AMCA 250-05

Annex D. Informative References NEMA MG-1, 1993 (R1997), Motors and Generators, National Electrical Manufacturers Association, Rosslyln, VA, U.S.A., 1997 ANSI S2.19 (1989) Balance Quality of Rotating Rigid Bodies, American National Standards Institute, New York, NY, U.S.A., 1989 ISO 1940-1:1986, Mechanical Vibration -- Balance Quality Requirements of Rigid Rotors -- Part 1: Determination of Permissible Residual Unbalance, International Organization for Standardization, Geneva, Switzerland, 1986

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AIR MOVEMENT AND CONTROL ASSOCIATION INTERNATIONAL, INC. 30 West University Drive Arlington Heights, IL 60004-1893 U.S.A.

Tel: (847) 394-0150 E-Mail : [email protected]

Fax: (847) 253-0088 Web: www.amca.org

The Air Movement and control Association International, Inc. is a not-for-profit international association of the world’s manufacturers of related air system equipment primarily, but limited to: fans, louvers, dampers, air curtains, airflow measurement stations, acoustic attenuators, and other air system components for the industrial, commercial and residential markets.