This standard specifies the engineering method for determining the sound power level of noise under free sound field conditions on a reflecting plane. The engineering method for determining the sound power level of noise in a reverberation chamber is included as an appendix (supplement) (Appendix D). This standard applies to the determination of the sound power level of noise for reciprocating pump units and steam reciprocating pumps, including prime movers, for motor, metering, pressure testing, and marine use. GB/T 9069-1988 Engineering method for determining the sound power level of noise for reciprocating pumps GB/T9069-1988 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Reciprocating pump noise
Determination of sound power level for noise emitted by reciprocating pump-Englneerlng method
Subject content and scope of application
UDC 621.651
GB 9069—88
This standard specifies the engineering determination method for the sound power level of noise under free sound field conditions on a reflecting plane. The engineering determination method for the sound power level of noise in a reverberation chamber is included as an appendix (supplement) (see Appendix D). This standard applies to the determination of the sound power level of noise from reciprocating pump units including prime movers, such as motors, meters, pressure test, and marine reciprocating pumps (hereinafter referred to as pump units).
2 Referenced standards
GB3102.7 Acoustic quantities and units
GB3241 1/1 and 1/3 octave band filters for sound and vibration analysis GB3785 Electroacoustic properties and test methods of sound level meters Acoustic terminology
GB 3947
Trial verification procedure for sound pressure level calibrators
JJG176
Trial verification procedure for sound level meters
JJG188
JJG277
Verification procedure for standard sound sources
3 Acoustic terms, acoustic quantities and units
The names and symbols of the terms, quantities and units used in this standard shall conform to the provisions of GB 3947 and GB 3102.7. 4 Quantities to be measured and their measurement errors
4. 1 Quantities to be measured
A-weighted sound power level and seven octave band sound power levels with center frequencies between 125 and 8000 Hz. 4.2 Measurement error
When measured in accordance with this standard, the standard deviation of the A-weighted sound power level shall not exceed 2 dB and the standard deviation of the seven octave band sound power level shall not exceed the values ​​specified in Table 1.
Approved by Guohao Machinery Industry Committee on April 5, 1988, implemented on January 1, 1989
Octave center frequency, Hz
250~500
1 000--4 000
GB 9069.---88
Standard deviation, dB
Note: Measurement error refers to the standard deviation of the votes caused by various factors: but does not include the change in the sound power of the machine itself caused by changes in the installation and operating status of the machine in each measurement.
5 Measurement environment
5.1 Measurement environment requirements
The ideal measurement environment should be a free sound field on a reflecting plane. The reflecting plane should be made of concrete, asphalt or other equally solid materials, and its size should be larger than the projection of the measuring surface on it. The measurement environment suitable for this standard is:
a, a laboratory with a free sound field above a reflecting plane, such as a semi-anechoic chamber. b. For outdoor sites with the above-mentioned reflection plane, there is no sound reflector within 10 m from the measuring point. c. For sites with an environmental correction value K not greater than 2.2 dB, such as ordinary rooms and outdoor sites that do not meet the requirements of point b, these sites require a reflection plane with the above-mentioned properties, and the environmental correction value K is determined according to the method specified in Appendix A (Supplement) so that the measured value can be corrected to the result under semi-free field conditions.
Note: Sound reflectors refer to buildings and some larger equipment. If the width of an object close to the sound source (such as the diameter of a pile or supporting member) is greater than one-tenth of its distance from the sound source, the object is considered to be a sound reflector. 5.2 Background noise requirements
The measurement should be carried out in a quiet environment. During the entire measurement process, the difference between the sound pressure level measured at each measuring point when the pump unit is working and the background noise sound pressure level is not less than 6 dB.
5.3 Wind speed
During measurement, the wind speed near the measuring point should be less than 6m/s (equivalent to level 4 wind). When the wind speed is greater than 1m/s, a wind shield should be used. 6 Test instruments
6.1 Overview
The test instruments shall use sound level meters of type 1 or above specified in GB3785 and other test instruments with equivalent accuracy. Extension cables or extension rods shall be used between the sound level meter or other test instruments and the microphone. The octave filter shall comply with the relevant provisions of GB 3241.
6.2 Calibration
Before and after each measurement, a sound level calibrator with an accuracy higher than ±0.5dB shall be used to calibrate the entire test instrument system at one or more frequencies. If the difference between the two calibration values ​​before and after the measurement exceeds 1dB, the measurement is invalid. The sound level calibrator shall be calibrated regularly in accordance with JJG176, and the sound level meter and other test instruments shall be calibrated regularly in accordance with JJG188 to ensure the accuracy of the test instruments. 7 Installation and operation of the unit
7.1 Installation of the pump unit
7.1.1 The pump unit shall be installed in accordance with the relevant technical conditions, and all accessories shall be installed completely, but no additional sound insulation and sound absorption components shall be added.
The outlet flow control, container, etc. shall be installed far away from the pump unit or appropriate measures shall be taken to prevent the noise radiated by them from affecting the measurement of the sound power level.
GB9069--88
7.1.3 When the noise of the suction and discharge pipelines is too large, appropriate measures shall be taken to prevent the noise radiated by them from affecting the measurement of the sound power level.
7.1.4 The noise from other test equipment shall be reduced to ensure the measurement accuracy of the sound power level. 7.2 Operation of the pump unit
7.2.1 The pump unit should be operated continuously under rated working conditions, and the noise measurement should be carried out after stabilization. If the measurement is carried out under other working conditions, mutual agreement should be obtained and detailed records should be made in the test report. 7.2.2 The medium used in the test is clean water. If other media are used, it should be stated in the test report. 8 Measurement of sound pressure level
8.1 Reference body
To determine the position of the measurement surface and the microphone, a minimum rectangular hexahedron that just envelops the measured pump unit (see Figures B3 to B8 in Appendix B) and is located on the reflection plane should be taken as the reference body. When determining the reference body, small protruding parts of the pump unit such as handles, connecting pipes, etc., which are non-main radiators of sound power, are not considered. 8.2 Measurement surface
The measurement surface is divided into a hemispherical measurement surface (see Figure B1) and a rectangular entry surface measurement surface (see Figure B2). The hemispherical measurement surface is preferred. 8.2.1 The center of the hemispherical measuring surface is the projection of the geometric center of the reference body on the reflection plane. The radius of the hemispherical measuring surface should be greater than twice the characteristic distance.
Characteristic distance 4. Calculated by formula (1):
d=(0.51,)2+(0.51)2+12
Where: d. Characteristic distance, m:
1, L. Length, width and height of the reference body, m. The radius r of the hemispherical surface is preferably selected as 1 or 2m.
8.2.1.1 If the characteristic distance d. is greater than 1m, the rectangular hexahedral measuring surface described in 8.2.2 should be used. 8.2.1.2 The area of ​​the hemispherical measuring disk surface is calculated by formula (2): S, = 2 yuan
Where: S,—area of ​​the hemispherical measuring surface, m, radius of the hemispherical measuring surface, m.
8.2.2 Rectangular hexahedron measuring surface
+（1）
（2）
8.2.2.1 The rectangular hexahedron measuring surface is located on the reflecting plane, and each face is parallel to the corresponding face of the reference body. The distance between each corresponding face is 1m. 8.2.2.2 The area of ​​the rectangular hexahedron measuring surface is calculated by formula (3): S1 = 4(ab + bc + ac)
Where S1 is the area of ​​the rectangular hexahedron measuring surface, m is the half of the length and width of the rectangular hexahedron measuring surface, and m is the height of the short hexahedron measuring surface.
8.3 Measurement point location
All measurement points should be located on the measurement surface determined in 8.2. 8.3.1 Ten measurement points are arranged on the hemispherical measurement surface. The measurement point locations and coordinates are shown in Figure B1 and Table B1 in Appendix B. (3)
8. 3.2 The measuring points on the rectangular hexahedron measuring surface are divided into basic measuring points and additional measuring points. There are 9 basic measuring points and 8 additional measuring points. The positions and coordinates of the measuring points are shown in Figure B2 and Table B2 of Appendix B. Additional measuring points should be added in the following cases:
GB 9069—88
The difference between the maximum and minimum decibel values ​​of the sound pressure level measured at the basic measuring points exceeds the number of measuring points. b. The dimension of any side of the reference body is greater than 2m.
8.4 Measurement
During measurement, the microphone should be facing the direction of the pump unit under test. The sound level meter should use the "slow" time weighting characteristic for measurement. When reading, if the sound level meter pointer swings, read the average value of the pointer swing. The center frequency is 125Hz multiple of the rated frequency; the observation time is at least 30s: A weighting and other multiples, the observation time is at least 10s. 8.5 Correction of background noise
8. 5. 1 One of the following situations is that the background noise is measured at only one measuring point: the background noise sound pressure level is more than 10dB lower than the unit noise sound pressure level. a.
b. The maximum size of the reference body is less than 1 m.
Otherwise, the background noise should be measured at each measuring point. 8.5.2 The background noise shall be corrected according to Table 2. Table 2
The integral of the measured pump unit noise and the background noise sound pressure level A6
8.6 Correction of measurement environment
The correction disk subtracted from the measured sound pressure level is invalid.
When there are unnecessary reflectors in the measurement environment, the measurement results must be corrected. The method for determining the environmental correction value K is shown in Appendix A (Supplement).
9 Calculation of the average sound pressure level and sound power level on the night surface 9.1 Calculation of the average sound pressure level on the measuring surface
The average sound pressure level Lw on the measuring surface is calculated according to formula (4): Z, = 10 lg
21001m
Wherein: Z, — the average A-weighted or octave-band sound pressure level on the measuring surface, dB (the reference value is 20 μPa)-(4)
L — the A-weighted or octave-band sound pressure level at the ith point after correction for background noise according to Article 8.5, dB (the reference value is 20 μPa)
Total number of measuring points
9.2 Calculation of the sound power level
The sound power level Lw is calculated according to formula (5):
Lw=(Lp-K) +10 ig(S/S.)
Where: Lu-
—A-weighted or multiple-range sound power level, dB (reference value is 1 pW) K
Environmental correction value, dB,
Measurement surface area, m,
reference area is taken as 1 rn.
（5）
10 Records
GB 9069-—88
The test record should include the following contents, and the record table is shown in Appendix C (reference). 10.1 Tested pump unit
B. Pump model, name, manufacturer, factory number and rated operating conditions and other related parameters b. Prime mover type, model, rated speed and power, C. Test operating conditions of the pump unit.
10.2 Acoustic environment
Reflecting surface conditions and draw a sketch of the sound source location a
Indoor, including the volume of the test room, total surface area and acoustic treatment of the room; h.
c. Outdoor, description of the surrounding environment and wind speed. 10.3 Test instruments
Model, name, factory number and manufacturer of the instrument; calibration method of the instrument system:
c. Date and department of calibration of the sound level calibrator. 10.4 Acoustic data
Dimensions of the base body, dimensions and surface area of ​​the measurement surface; Location of measurement points and draw a sketch:
A sound level and octave band sound pressure level at all measurement points; c
Background noise sound pressure level at the measurement point and the corresponding correction value, according to the environmental correction value KI determined in Appendix A (Supplement).
Measure the average sound pressure level of the surface, calculate the A-weighted sound power level and the octave band sound power level, and express them in a spectrum diagram. e.
10.5 Meteorological conditions
Temperature, relative humidity and atmospheric pressure.
10.6 Other contents
Measurement personnel and measurement time, location and other conditions that should be explained. 11 Measurement report
The noise measurement report of the pump unit should include the following contents, and its form is shown in Appendix C (reference). Model, name, factory number and manufacturer of the pump: a.
Type, model, speed, power, rated working condition and measurement working condition of the prime mover;
dA sound power level and multiple rated range sound power level: e
Indicate that the sound power level is measured according to the method of this standard. A1 Overview
GB 9069-88
Appendix A
Determination of environmental correction value K
(Supplement)
This appendix specifies the determination of environmental correction value K by absolute comparison test method (standard sound source method) or reverberation time method. A1.1 Requirements for environmental correction value K
Group. In a given test room, the ratio of room sound absorption A to the area of ​​the measurement surface A/S should be greater than 6, and the environmental correction value K determined by the method in this appendix should not be greater than 2.2 dB. b. When the environmental correction value K is greater than 2.2 dB, sound absorption measures should be adopted or the test environment should be changed to reduce the K value. c. When the environmental correction value K is greater than 2.2 dB and less than 7 dB, the A-weighted sound power level shall be determined according to the test procedure given in this standard; if used for comparison of sound power levels of similar units in the same test environment, the standard deviation shall not be greater than 3 dB. A2 Absolute comparison method
'A2.1 Method
The standard sound source that has passed the verification according to JJG 277 is placed in the test environment at the same position as the pump unit under test, and the sound power level of the standard sound source is measured and calculated according to the methods in Chapters 8 and 9 (no environmental correction item is required). When the standard sound source is placed at multiple locations, the sound power level of the on-site standard sound source should be measured at each placement point, and the average value of the surface average sound pressure level of the standard sound source placed on all positions is calculated. Then the sound power level is calculated. The environmental correction value K is obtained by formula (A1): K = Lw - Lw
Where: L——the sound power level of the standard sound source measured on site, dB (the reference value is 1pW) Lw——the sound power level calibrated by the standard sound source, dB (the reference value is 1pW). A2.2 Placement of standard sound source
The placement of standard sound source is divided into two methods: substitution method and side placement method. .(Al)
A2.2.1 When the measured sound source can be removed from the test site, the substitution method is used. Place the standard sound source on the reflection plane at the same position as the measured sound source. Generally, it only needs to be placed at one position at the geometric center. For pump units with a length-to-width ratio greater than 2, the standard sound source should be placed at four positions, which are the midpoints of the four rectangular sides of the reference body projected on the reflection plane. A2.2.2 When the measured sound source cannot be removed from the test site, the side placement method is used. The standard sound source is placed at the same four positions as in A2.2.1. If the surface of the pump unit is attached with sound-absorbing materials, the side placement method is not applicable, and the A3 method is used. A3 Reverberation Time Method
This method is applicable to rooms with a shape similar to a cube. The environmental correction value K is calculated according to formula (A2): K = 10 Ig
Where: S—the area of ​​the measurement surface, m
A——the sound absorption of the room, m.
The sound absorption A of the room is determined by measuring the frequency band reverberation time. The sound absorption A is given by formula (A3): A = 0. 16(V/T)
-「A3)
Wherein, V→
Room volume, m\
Octave reverberation time, s.
The K value can also be found from Figure A1:
GB 9069—88
The measurement of reverberation time shall be in accordance with relevant standards. When this method is used, the A-weighted sound power level is synthesized by the method of Chapter A4. The calculation of the A-weighted sound power level synthesized from the octave band sound power level A4
is calculated according to formula (A4):
Lwa = 10 lg >
Where: LWA
A-weighted sound power level, dB (reference value is 1pW); i-th octave sound power level, dB (reference value is 1pW): C, octave A-weighted attenuation (see Table A1). Table AI
Octave center frequency, Hz
A-weighted attenuation value C, dB
GB 906988
Appendix B
Diagrams of reference bodies, measuring surfaces, measuring point positions of pump units and reference bodies of several typical pump units (supplements)
Hemispherical measuring surface, measuring point positions and coordinates are shown in Figure B1 and Table B1B1
Reference body
Sub-surface
○Measurement point position measurement
Reference body, hemispherical measuring surface, measuring point position diagram B1
Measuring point number
Rectangular hexahedron measuring surface, upper measuring point position and coordinates are shown in Figure B2 and Table B2. z/r
Reference body
Point number
Measurement surface
GB 9069—88
Reference body, rectangular hexahedron measuring surface and measuring point position table B2wwW.bzxz.Net
Note, z should not be less than 0.15m.
B3 Typical reference bodies of pump units: Y
0 Reference measuring point
X Additional measuring point
GE9069-88
Figure B3 Reference body of horizontal motor-driven reciprocating pump unitFigure B4 Basic thrust body of vertical motor-driven reciprocating pump unitGB9069—88
Figure B5 Basic thrust body of metering pump unit
Figure B6 Reference body of marine pump unit
GB 9069—88
Figure B? Reference body of pressure test pump unit
Figure BB Reference body of steam pump unit
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