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GB/T 21231.1-2018 English PDF

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GB/T 21231.1-2018: Acoustics -- Measurement of airborne noise emitted and structure-borne vibration induced by small air-moving devices -- Part 1: Airborne noise measurement
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GB/T 21231.1: Evolution and historical versions

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GB/T 21231.1-2018English724 Add to Cart 5 days [Need to translate] Acoustics -- Measurement of airborne noise emitted and structure-borne vibration induced by small air-moving devices -- Part 1: Airborne noise measurement Valid GB/T 21231.1-2018
GB/T 21231-2007English954 Add to Cart 4 days [Need to translate] Acoustics -- Method for the measurement of airborne noise emitted by small air-moving devices Obsolete GB/T 21231-2007

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Basic data

Standard ID GB/T 21231.1-2018 (GB/T21231.1-2018)
Description (Translated English) Acoustics -- Measurement of airborne noise emitted and structure-borne vibration induced by small air-moving devices -- Part 1: Airborne noise measurement
Sector / Industry National Standard (Recommended)
Classification of Chinese Standard A59
Classification of International Standard 17.140
Word Count Estimation 38,31
Date of Issue 2018-03-15
Date of Implementation 2018-10-01
Issuing agency(ies) State Administration for Market Regulation, China National Standardization Administration

GB/T 21231.1-2018: Acoustics -- Measurement of airborne noise emitted and structure-borne vibration induced by small air-moving devices -- Part 1: Airborne noise measurement


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Acoustics--Measurement of airborne noise emitted and structure-borne vibration induced by small air-moving devices--Part 1. Airborne noise measurement ICS 17.140 A59 National Standards of People's Republic of China Replace GB/T 21231-2007 Acoustic air noise radiated by small ventilation devices and Measurement of structural vibration caused Part 1. Air noise measurement Part 1. Airbornenoisemeasurement (ISO 10302-1.2011, IDT) 2018-03-15 released.2018-10-01 implementation General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China China National Standardization Administration issued

Content

Foreword III Introduction IV 1 Scope 1 2 Normative references 1 3 Terms and Definitions 2 4 Measurement scope 4 5 test box design and performance requirements 4 6 Installation 6 7 Ventilation operation 7 8 Measurement step 8 9 Measurement uncertainty 9 10 Record content 10 11 Report content 10 Appendix A (Normative) PQ curve measurement method for micro fans 20 Appendix B (informative) Impact of air density 21 Appendix C (informative) Data Expression Format 22 Appendix D (informative) Ventilation Equipment Noise Technical Note 26 Appendix E (informative) Guide to Measurement Uncertainty Information 27 Reference 32

Foreword

GB/T 21231 "Measurement of airborne noise and acoustic vibration caused by acoustic small ventilation devices" includes the following two parts. --- Part 1. Air noise measurement; --- Part 2. Structural vibration measurement. This part is the first part of GB/T 21231. This part is drafted in accordance with the rules given in GB/T 1.1-2009. This part replaces GB/T 21231-2007 "Measurement method for radiated air noise of acoustic small ventilation devices". Compared with GB/T 21231-2007, the main technical changes in this section are as follows. --- Added the terms and definitions (see 3.1.2, 3.2.3); --- In order to adapt to vibration measurement, the adapter plate has added a damper plate replacement scheme (see 5.2); --- Increased the pq curve measurement method for small fans (see Appendix A); --- Added guidelines for progress in measurement uncertainty information (see Appendix E). This section uses the translation method equivalent to the ISO 10302-1.2011 "acoustic small ventilation device radiated air noise and caused by the knot Measurement of vibrations - Part 1. Air noise measurement. The documents of our country that have a consistent correspondence with the international documents referenced in this part are as follows. ---GB/T 3767-2016 Acoustic sound pressure method for the determination of noise source sound power level and sound energy level reflection surface above the approximate free field Engineering method (ISO 3744.2010, IDT) ---GB/T 6881.1-2002 Acoustic sound pressure method for the determination of noise source sound power level and sound power level reverberation chamber precision method (ISO 3741.1999, IDT) ---GB/T 6882-2016 Acoustic sound pressure method for the determination of noise source sound power level and sound energy level anechoic chamber and semi-anechoic chamber precision Law (ISO 3745.2012, IDT) This part was proposed by the Chinese Academy of Sciences. This part is under the jurisdiction of the National Acoustic Standardization Technical Committee (SAC/TC17). This section was drafted by. Institute of Acoustics, Chinese Academy of Sciences, Shenzhen Zhongya Electromechanical Industry Co., Ltd., Anhui Weiwei Plastic Parts Group Co., Ltd. Division, Tongji University, Beijing Labor Protection Science Research Institute, Nanjing University, Dalian Mingri Environmental Engineering Co., Ltd., China Metrology Science Research Institute, Shanghai Jiaotong University, Changsha Aobang Environmental Protection Industry Co., Ltd., Shanghai Xinhuajing Environmental Protection Engineering Co., Ltd., Northwestern Polytechnical University, Shanghai Environmental Science Research Institute, Anhui Vocational and Technical College. The main drafters of this section. Cheng Mingkun, Fang Qingchuan, Zhang Bin, Lu Yadong, Li Xiaodong, Yin Yi, Li Zhiyuan, Li Jun, Li Bin, Yu Wuzhou, Mao Dongxing, Li Xiaokuan, Song Ruixiang, Qiu Xiaojun, He Longbiao, Jiang Weikang, Mo Jianyan, Chen Ke'an, Liu Yunfeng, Wu Daozhong, Wang Bing, Zhou Yude, Zhu Wenying, Xu Xin, Bao Junyao. The previous versions of the standards replaced by this section are. ---GB/T 21231-2007.

Introduction

This part of GB/T 21231 specifies small ventilation devices mainly used for cooling electronic equipment such as computers and communication equipment. Radiation air noise measurement method and report preparation content. In order to maintain consistency with the measurement of radiated noise of such equipment, this section uses the description of the radiated noise in ISO 7779 and the sound power level. Measurement methods. The described amount of total noise radiation of the tested ventilation device is the A-weighted sound power level. 1/3 octave sound power level is noise radiating Describe the amount in detail. In addition to the 1/3 octave sound power level, the octave sound power level can also be used. Acoustic air noise radiated by small ventilation devices and Measurement of structural vibration caused Part 1. Air noise measurement

1 Scope

This part of GB/T 21231 specifies the noise of airborne noise radiated by small ventilation units used to cool electrical, electronic and mechanical equipment. Power level measurement method. Such small ventilation devices include axial fans, tubular axial fans, vane axial fans, centrifugal fans, electric impellers, and The form of change. This section describes test equipment and methods for measuring airborne noise radiated by small ventilation units. The air noise is the body of the ventilation device The product flow and its function as the static pressure of the fan formed on the test device. The purpose of this section is to provide ventilation equipment manufacturers with ventilation Manufacturers of cooling electronics and similar applications, as well as test labs. This part is a manufacturer of ventilation equipment, equipment manufacturers and testing Try the laboratory to provide a way to get comparable results. The results of this section can be used for engineering information and performance identification, and this method can also It is cited in the procurement technical specification and the contract signed between the buyer and the seller. The ultimate goal of noise radiation measurement is to provide designers with Data to assist in the design of electrical, electrical or mechanical equipment containing one or more ventilation devices. Based on empirical data, the method of calculating the maximum (volume) flow rate specified in this section by the test of the scaling box is OK.

2 Normative references

The following documents are indispensable for the application of this document. For dated references, only dated versions apply to this article. Pieces. For undated references, the latest edition (including all amendments) applies to this document. ISO 3741 acoustic sound pressure method for the determination of noise source sound power level and sound energy level reverberation chamber precision method (Acoustics-Determi- Nationofsoundpowerlevelsandsoundenergylevelsofnoisesourcesusingsoundpressure-Precision Methodsforreverberationtestrooms) ISO 3744 Acoustic Sound Pressure Method for the Determination of Sound Sources of Noise Sources and Approximate Free Fields Above the Acoustic Energy Level Reflective Surface (A- coustics-Determinationofsoundpowerlevelsandsoundenergylevelsofnoisesourcesusingsound pressure-Engineeringmethodsforanessentialyfreefieldoverareflectingplane) ISO 3745 acoustic sound pressure method for the determination of noise source sound power level and sound energy level anechoic chamber and semi-anechoic chamber precision method (Acoustics-Determinationofsoundpowerlevelsandsoundenergylevelsofnoisesourcesusing soundpressure-Precisionmethodsforanechoictestroomsandhemi-anechoictestrooms1) ISO 5801.2007 Industrial fans with standardized air ducts for performance testing (Industrialfans-Performancetesting Usingstandardizedairways) ISO 7779.2010 Acoustics - Information technology equipment and communication equipment - Air noise measurement (Acoustics-Measurementof Airbornenoiseemittedbyinformationtechnologyandtelecommunicationsequipment) ISO /IEC Guide 98-3 Measurement uncertainty - Part 3. Guidance for the expression of measurement uncertainty [Uncertaintyofmeas- urement-Part 3. Guidetotheexpressionofuncertaintyinmeasurement(GUM.1995) ANSI/ASAS2.32 Experimental methods for the determination of mechanical admittance - Part 2. Single-point translational method perimentaldeterminationofmechanicalmobility-Part 2.Measurementsusingsingle-pointtranslationalexci- Ttation JBMS72.2003 Airborne noise measurement method for acoustic microfans (Acoustics-Methodforthemeasure- Mendevairbornenoiseemittedbymicro-fans)

3 Terms and definitions

The following terms and definitions apply to this document. 3.1 General definition 3.1.1 Ventilation unit air-movingdevice (AMD) Fan fan A device that drives the impeller to rotate by electronically or mechanically controlling the motor to flow air. Note 1. A ventilator has at least one air inlet and one air outlet. The air inlet and outlet may have connections to the piping system or other airflow paths. Note 2. Testing may be performed in a specific frame, motor, rotor, and different accessories (eg, guard) configurations. For this part, each such configuration is called A ventilation device. Note 3. The term “fan” in this section is used to mean “ventilation device” and can be in various forms such as axial flow, centrifugal or mixed flow. Need to distinguish type At the time, an attribute (such as axial flow, centrifugal or mixed flow, etc.) is added. 3.1.2 Micro fan fan The ventilation device with a maximum volume flow rate less than or equal to 0.015 m3/s. Note 1. The micro-fan is a refinement of the fan when tested in this section. Note 2. Table 4 of 22.4.2 of ISO 5801.2007 is only applicable to the range of Reynolds number not less than 12000. The lower limit of this Reynolds number and volume flow 0.01m3/s approximates. Since many cooling applications pursue lower displacement fans, the method in Appendix A of JBMS-72.2003 is used. Measure the pq curve of the microfan. 3.2 Acoustic definition 3.2.1 Sound power level soundpowerlevel LW The base 10 logarithm of the ratio of the sound power P to the reference sound power P0 is expressed by the equation (1) and the unit is decibel (dB). LW = 10lg P0 (1) In the formula. P0---reference sound power, in watts (W), P0 = 1pW. Note. If the frequency band weighted and/or specified in IEC 61672-1 [6] is used, it is recommended to indicate it with the corresponding subscript. For example, LW A indicates A weighting Sound power level. 3.2.2 Test frequency range frequencyrangeofinterest From 1/3 octave frequency range from 100Hz to 10kHz. Note 1. ISO 266 [1] gives the center frequency of 1/3 octave. Note 2. For the measurement of small, low-noise fans (ie micro-fans), the radius of the test hemisphere may be less than 1 m depending on the size of the test box used, but should not Less than 0.5m. However, a radius of less than 1 m limits the frequency range of the test. For details, please refer to B.1 in ISO 7779.2010. 3.2.3 Test box insertion loss insertionlossoftestplenum ΔL The sound power level difference measured when the sound source is installed inside and outside the test box is defined as equation (2). ΔL=LW, out-LW,in (2) In the formula. LW, out---the sound power level when the sound source is installed outside the test box; LW,in --- The sound power level when the sound source is installed in the test box. Note. The insertion loss of the test box is expressed in dB. 3.3 Aerodynamic definition 3.3.1 Test box testplenum A structural member on which the ventilating device to be tested is mounted for measuring noise radiation. Note. The test box creates ventilation resistance to the ventilation unit, but allows the noise of the ventilation unit to enter the test chamber with little additional attenuation. Can be tested The sound power radiated by the ventilation device outside the box is measured. 3.3.2 Ventilation performance curve air-movingdeviceaerodynamicperformancecurve "pq curve" A plot of the static pressure of a fan as a function of volumetric flow under standard air conditions and a constant operating voltage and frequency. Note 1. For the purposes of this section, the modifier “pneumatic” is inserted before the “performance curve” to distinguish the noise radiation characteristics from the volumetric flow. Note 2. The representation of this curve is taken from ISO 5801 or Appendix A, which are complementary to each other. The method specified in Appendix A applies to volume flow not Small air mobile devices over 0.015m3/s. Note 3. For convenience, this section uses the term “pq curve”. 3.3.3 Point of operation The point on the aerodynamic performance curve of the ventilation device that corresponds to a specific volume flow. Note. When testing, the operating point is controlled by adjusting the slider of the test box outlet part. 3.3.4 Full static efficiency of ventilation unit overalstaticefficiencyofair-movingdevice Ηo,s The product of the fan static pressure and volume flow divided by the input electrical power. Note 1. The full static efficiency of the ventilation device is expressed as a percentage, as in equation (3). Ηo, s= Ps, fqV Pinput ×100 (3) In the formula. Ps, f---fan static pressure, the unit is Pascal (Pa); qV --- volume flow in cubic meters per second (m 3/s); Pinput---The motor input power provided at the motor terminals in watts (W), (effective power, reactive power without resistance component). Note 2. The definition of the ventilation device includes the motor, the impeller and the frame. Therefore, full static efficiency includes both motor efficiency and aerodynamic efficiency of the impeller and frame. 3.3.5 Standard atmospheric density standardairdensity Air density at standard atmospheric conditions. Note. The air density under standard atmospheric conditions is 1.20kg/m3. 3.3.6 Standard atmospheric conditions (for aerodynamic performance measurements) standardairconditions(foraerodynamicperformancemeasurement) Specific atmospheric conditions. Note. The standard atmospheric conditions are. temperature 20 ° C, relative humidity 50%, atmospheric pressure 1.013 × 105 Pa.

4 Measurement scope

The test data shows that the method is applicable when the maximum volume flow rate qV, max and the static pressure of the fan do not exceed 750 Pa. qV,max is the test The function of the nominal air volume V of the test box, as in equation (4). qV,max= qV,0 V0 V (4) In the formula. qV,max---The maximum volume flow of the scale test box, in cubic meters per second (m3/s); qV, 0 --- The maximum volume flow of the full-scale test box, in cubic meters per second (m3/s), qV, 0 = 1m3/s; V0 --- The full scale test box nominal air volume as defined in Chapter 6. The unit is cubic meter (m3), V0=1.3m3; V --- scale test box nominal air volume in cubic meters (m3). Note 1. The air volume of 1.3m3 in the full-scale test box is calculated by 1.2 (width) × 1.2 (deep) × 0.9 (height) = 1.296m3. Note 2. The nominal air volume refers to the approximate air volume calculated from the outer dimensions of the test box. Such as a 1/4 scale test box, excluding the height of the support legs, Its nominal air volume is V = blh = 0.3 m x 0.3 m x 0.225 m = 002025 m3, where b is the width, l is the depth, and h is the height. In combination with the purpose of this section, if the maximum volume flow of the fan is within the range of equation (4), it is recommended to use a test box as small as possible. The measurements specified in this section refer to the method of determining the sound power level in a qualified environment as given in ISO 7779. The ISO 3741 reverberation chamber comparison method can also be applied to the direct method of approximating the free field above the reflection surface of ISO 3744 or ISO 3745. This section The prescribed method can be used for ventilation devices that radiate noise as follows. a) broadband noise; b) narrowband noise; c) Noise with discrete frequency components. The methods specified in this section can be used to test the noise level of a single product. If the noise value is from multiples of the same series The results obtained from the product test can be used to determine the statistical value of the product line. Tip. In practical applications, vibration, airflow disturbances, insertion loss and other phenomena may change the acoustic power of the radiation; therefore, when ventilating When the device is installed in the device, the measurement results obtained according to the methods in this section may vary. Note 3. This section does not describe the measurement of structural sound caused by ventilation.

5 test box design and performance requirements

5.1 Overview The design is intended to meet the limits of the specified maximum volume flow and maximum fan static pressure. This design provides adjustable ventilation Flow resistance, while ensuring sound. Note 1. Please refer to 5.5 for the requirements for confirming the sound transmission rate according to this section. The reference design of the test box is given in 5.2~5.6, as shown in Figure 1~8. These sub-clauses and other provisions of this section also indicate The design can be different from this design, mainly in reducing the linear size of the frame and the selection of certain dimensions of other components, while at the same time The geometric ratio remains the same within the 1/4 scale. Such reduction reduces the maximum allowable volume flow of the tested ventilation unit and the test chamber The decrease in the product is proportional to the cube, which is reduced by the cubic of the linear scale [see equation (4)]. Note 2. These changes may be more suitable for smaller or quieter fans, as well as for test chambers that are too narrow for a full-scale test chamber. The standard deviation of reproducibility resulting from the above allowable changes is within the scope of Table 1. Other changes to the reference design for the sound power of the ventilation unit The extent of the uncertainty in the measurement uncertainty is not clear. 5.2 Test Box. Main Components 5.2.1 General. As shown in Figure 1, the test box shall consist of a sealed cavity covered with a layer of sound-permeable but airtight polyester film on its frame. A mounting plate and an adjustable outlet end unit. The test box shall meet the requirements specified in 5.2.2~5.2.7. 5.2.2 Box size. Figure 1 shows the dimensions of the full-scale test box. 5.2.3 Cover layer. An isotropic polyester film with a nominal thickness of 25 μm to 50 μm. The overlay can be protected with a bead (see Figure 1 and figure 2). 5.2.4 Frame. A suitable material with a nominal size of 50 mm x 50 mm is used to ensure the structural integrity of the test box. The gusset is recommended Wooden structures sometimes require other materials (see Figure 3). The linear dimension of the frame including the thickness of the frame member should be larger than the test box Small proportion. 5.2.5 Frame material. Experience has shown that both hardwood (such as birch) and aluminum pipe have sufficient strength, rigidity and durability, and Acoustic performance requirements listed in 5.5. 5.2.6 Vibration isolation. For any size test box, the box legs or supports shall provide vibration isolation between the test box and the floor (platform). Purpose of vibration isolation It is to block the vibration transmission path between the test box and the floor. Regardless of the method chosen, the total height of the full test leg should be kept at 0.1m. (See Figures 1 and 3). The height of the 0.1m box leg should be proportional to the box size. 5.2.7 Fan static pressure hole measurement. The pressure ring should be directly fixed behind the mounting plate, and the size of the ring matches the circumference of the mounting plate (see Figure 4). The circumference of the pressure ring should match the size of the test box. The pressure ring diameter and the static pressure hole are not necessarily proportional, but need to remain unchanged. 5.3 Mounting plate components The mounting plate components shall consist of a type of adapter plate that is packaged onto a reinforced rubber plate that is then packaged for testing by aluminum beading. On the box frame (Figure 1, Figure 4 and Figure 5). Secure the fan to the rubber plate with the adapter plate. Can be adapted as shown in Figure 5. In the form of installation of the axial flow fan, other installation forms more suitable for the particular ventilation device to be tested may also be used. The adapter plate should not handle airflow Interference is generated and does not produce any additional acoustic radiation other than the noise of the ventilation device itself. The mounting plate components (including the adapter plate and the flexible plate) can be replaced by a single damper plate with an opening similar to the adapter plate (but without the adapter) Plate), damper material requirements have no significant effect on airborne sound measurements. The technical requirement for the damping plate is to freely suspend the plate with a size of 1 m2 without fan mounting holes through two corners and measure at its center. The mechanical admittance level in the frequency range of 25Hz~5000Hz does not exceed -45dB (reference value. 1m/Ns), and the mechanical admittance level measurement should be ANSI/ASAS2.32. The tolerance of the admittance stage is ±8dB from 2Hz to 100Hz, ±4dB from 100Hz to.200Hz, and ±2dB from.200Hz to 5000Hz. These tolerance limits ensure that the damper plate has sufficient damping to prevent frame excitation. These replacement plates are sometimes used in connection with fan vibration In measurement (see GB/T 21231.2). Using the same mounting plate for acoustic and vibration measurements will increase the efficiency of joint testing. If replaced For the design of the mounting plate, the mechanical admittance of the replacement version should be described in the test report according to the impedance test of the plate. The opening of the adapter plate shall be the same as recommended by the manufacturer of the ventilation device. The opening of the pressure plate frame and the rubber plate shall be larger than the opening of the adapter plate. Minimize disturbances to the airflow. The length, width, thickness of the aluminum bead and the length and width of the reinforced rubber mounting plate should be proportional to the size of the test box. Other sizes, including the thickness of the board, may be disproportionate. 5.4 Adjustable air outlet parts The adjustable air outlet part shall consist of a plate with fixed openings and a slider (slidable plate) for the exit of the full-scale test box The area is continuously adjustable from 0m2 to 0.2m2 (see Figure 6 to Figure 8). The maximum area of the outlet should be proportional to the square of the linear ratio of the test box. Note. The operating point of the ventilation unit is controlled during the test by adjusting the position of the outlet part slide. 5.5 Test box insertion loss For this part, the validity of the test box is evaluated by the insertion loss of the test box (3.2.3). According to the following steps a) ~ c), the 1/3 octave band insertion loss of the test box should not exceed -2dB~3dB, it is recommended not to exceed ±1.5dB. a) The sound source (such as the speaker) sound power level should be measured twice. once the sound source is in the test box, and the other time the sound source is outside the test box, but The measurement should be in the same location in the test chamber. Hemispherical sound transmission if the insertion loss is measured in a free field above the reflecting surface The array should be centered on the sound source. b) if the position of the speaker source is moved relative to the reflective surface (ground and mounting panel) in two sound power measurements, then Measurement uncertainty may occur. To do this, mount the sound source on the ground, remove the mounting panel and flip the test box 90° so that The face normally covered by the mounting panel is parallel to the ground and the exit is on the top surface. This allows the test box to be mo...

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