GB/T 3770-1983 Determination of sound power level of noise for woodworking machine tools
Some standard content:
National Standard of the People's Republic of China
Determination of sound power level for noise emitted by woodworking machinery
Determination of sound power level for noise emitted by woodworking machineryThis standard applies to the measurement of noise emitted by various types of woodworking machines. UDC 534.6:674
GB 3770-83
This standard specifies an engineering method for measuring the sound pressure level on an imaginary measuring surface that envelops a woodworking machine and obtaining its sound power level by calculation. The standard deviation of the measured A sound power level is not greater than 2 dB. This standard is formulated with reference to the national standard GB3767-83 "Determination of sound power level of noise source - upper range method and quasi-engineering method". 1 Measurement items
1.1 Measure the average A sound level LpA of the measuring surface of the woodworking machine and determine the A sound power level LWA. And as needed, measure the average frequency band sound pressure level L of the measuring surface of the woodworking machine and determine the frequency band sound power level LWi. 1.2 Draw a sound power spectrum of 1/1 octave (or 1/3 octave). The frequency range is 63~8000Hz (for 1/3 octave, the frequency range is 63~10000Hz). 1.8 Determine the direction of the strongest radiated noise of the woodworking machine at the specified height. 2 Measuring instruments
2.1 Use a type I sound level meter with an accuracy of ±0.7dB or other measuring instruments with comprehensive performance equivalent to this accuracy. 2.2 Sound level meters, 1/1 octave (or 1/3 octave) filters and other instruments should comply with the relevant provisions of national standards GB3785-83 "Electrical and acoustic properties and test methods of sound level meters" and GB3241-82 "1/1. and 1/.3 octave filters for sound and vibration analysis".
2.3 Measuring instruments should be calibrated regularly. The entire measurement system, including microphones and cables, shall be calibrated in accordance with relevant regulations before and after each measurement. If the difference between the two calibration values before and after the measurement exceeds 1 dB, the measurement is invalid. a Measurement environment and correction value
3.1 Measurement environment
The measurement shall be carried out outdoors (in an open, flat place with a reflective surface) or on a hard ground in a large room. The size of the reflective ground shall be greater than the projection range of the measurement surface on the ground/2 m (1 is the wavelength of the lowest frequency in the main measurement frequency range, m). The measurement site shall meet the following requirements:
Where: A——room sound absorption, m2
S measurement surface area, m2.
Note: If the measurement site cannot meet or equal to 6, but meets the requirement of greater than or equal to 4. The standard method specified in GB 3767-83 can be used for measurement. At this time, the standard deviation of the A sound power level shall not exceed 3 dH. This shall be noted in the measurement report. 3.2 Background noise correction: The measurement should be carried out in a quiet environment. During the whole measurement process, the background noise (A sound level or multiple frequency band sound pressure level) at each measuring point should be at least 10dB lower than the corresponding sound pressure level of the machine tool being measured. If the above requirements cannot be met, when the difference between the two is 6-10dB, the measured value should be corrected for the influence of background noise. The background noise correction value K is obtained according to Table 1.
The difference between the sound pressure level measured when the machine tool on the tested wood is running and the sound pressure level of the background noise
Background noise correction value K,
3.3 Environmental correction
Invalid measurement
When measuring mice outdoors or in a large room, the measured value should be corrected for the influence of environmental reflection. The environmental correction value K is obtained according to Appendix A. 3.4 When measuring outdoors, in order to avoid the influence of wind, the microphone should be added with wind pump. When the wind speed exceeds 6m/s (equivalent to level 4 wind), measurement should not be carried out.
3.5 Temperature and air pressure correction,
When the temperature and air pressure of the test environment deviate from the temperature! = 20℃, air pressure P, = 100kPa, the correction value caused is equal to or greater than 0.5dB, correction should be made. The calculation formula of the correction value K is as follows: Ks= 101g (v
Formula 1: t——Temperature of the test environment, ℃3Po——Air pressure of the test environment, kPa.
, Installation and operation of woodworking machine tools
4.1 Woodworking machine tools should be installed according to the normal use conditions specified in the product technical manual. Note: If the above requirements are not met, the installation conditions selected during the measurement should be recorded and reported. 4.2 Woodworking machine tools and their auxiliary equipment should be measured after 15 minutes of normal, continuous and stable operation. 4.3 Woodworking machine tools should be measured with the specified tools installed, no load, and maximum speed. (1)
4.4 For woodworking machines with multiple speeds, different strokes, and multiple tools installed, the speed, stroke, and tool that produce the maximum noise should be measured under no-load conditions.
4.5 For multi-purpose woodworking machines that can be operated simultaneously, the measurement should be carried out with the specified tools, loads, and maximum speeds.
4.6 The installation method of the fixture should comply with the requirements of the product technical manual. 4.7 If load measurement is required, the loading method, operating conditions, etc. should be specified in the corresponding technical conditions according to different products. Specific provisions shall be made.
5 Measurement method, measurement surface and measurement point location 5.1 Measurement method
5.1.1 Use the A-weighted network of the sound level meter to measure the A sound level. Use a 1/1 octave (or 1/3 octave) filter to measure the band sound pressure level. 5.1.2 When using a free-field microphone, the microphone should point to the sound source. 5.1.3 The dynamic characteristics of the sound level meter use the "slow" gear. The reading is the average of the pointer swing. 5.1.4 In order to avoid the reflection of the operator's body during measurement, an extension cable should be used as much as possible. The operator should be at least 1 meter away from the microphone. Less than 0.5m. 5.2 Measuring surface
5.2.1 The measuring surface adopts the enveloping surface of a rectangular hexahedron. GB3770—B3
5.2.2 The outer dimensions of the woodworking machine are simplified into a reference rectangular hexahedron (called the reference body), and individual protruding parts that have little effect on the noise radiation of the woodworking machine can be omitted. The enveloping surface of the rectangular hexahedron that is 1m away from each side of the reference body is the measuring disk surface (see Figures 1 and 2). Reference body
Reading surface
O-Basic measuring point auxiliary measuring point
Figure 1 The height of the reference body is less than 2 m when the measurement surface, the position and number of measuring points 11
a basic measuring point a auxiliary measuring point
tree canal surface response
Figure 2 The measurement surface when the height of the reference body is greater than or equal to 2m, the position and number of measuring points - (2)
GB 3T70—83
When it is less than 2m, select according to Figure 1, among which points 1 to 9 are basic measuring points, points 10 to 17 are auxiliary measuring points, and their measuring point coordinates are shown in S = 4 (ab+bc+co)
When 1, is greater than or equal to 2, select according to Figure 2, among which points 1 to 13 are basic measuring points, points 14 to 25 are auxiliary measuring points, and the measuring surface area (excluding the ground) of the measuring points is calculated by the following formula: - The distance between the reference body and the measurement surface, generally d = 1m. Measuring surface area, m
l1, 12, 1g—respectively the length, width and height of the reference body, m15. .1 The measuring point (microphone position) is arranged on the measuring surface. +d,m,
b=+d,m;
Where: S-
c=l,+d,mt
5. a The coordinates of the measuring point position
see Table 3.
Table 2.
Table 2 The coordinates of the measuring point in Figure 1
GB3770—83
The coordinates of the measuring point in Figure 2
5.3.2 The basic measuring point is the measuring point that must be selected, and the auxiliary measuring point is selected in any of the following cases. .When the difference between the maximum and minimum sound pressure levels measured at the basic measuring point exceeds the number of measuring points, b.When it is greater than 2m or greater than 2m;
c.When the noise radiated by the machine is highly directional. 5.3.3When drawing the sound power spectrum, only five measuring points, 1, 2, 3, 4 and 19 (Figure 1) or 13 (Figure 2) can be measured. 5.3.4Find the maximum A sound level point at the horizontal height of No. (Figure 1) or No. 1: (Figure 2) and mark its position to indicate the strongest direction of noise radiation from the woodworking machine.
5.3.5If necessary, additionally test the A sound level at the operator's ear position. The measuring point position is the position where the operator is usually located, the height is 1.5m, and the number of measuring points is equal to the number of operators of the woodworking machine. Record the measurement results and the location of the measuring points in the report. 5.3.6When calculating the average A sound level, the measured values of 5.3.4 and 5.3.5 are not included. 6Calculate
6.1 The average A sound level of the measuring surface is calculated by the following formula: Formula: L
GB3770—83
Lpa= 10lg[
100.1(pK）
Average A sound level of the measuring surface, dB (reference value: 20μPa), LpAi
—A sound level measured at the i-th measuring point, dB (reference value: 20μPa), Ki—positive value of background noise at the i-th measuring point, dB, number of measuring points.
6,2The average sound pressure level of each frequency band on the measuring surface is calculated by the following formula: Lpp=10ig[210.(-Kin)
Wherein: Lpj
-the average sound pressure level of each frequency band on the measuring surface, dB (reference value: 2uuPa)-the sound pressure level of each frequency band measured at the i-th measuring point, dB (reference value: 20μPa):-the background noise correction value of each frequency band at the i-th measuring point, B,-the number of measuring points.
6.3A sound power level is calculated by the following formula:
LwA= (LpA-Kz- K) + 101g
Wherein: LWA-
A sound power level, dB (reference value is, 1pW), average A sound level of the measuring surface, dB (reference value: 20μPa); - environmental correction value, dB,
Temperature and air pressure correction values, dB,
-measuring surface area, m2
-reference area, S= 1 m2.
6.4 The sound power level of the measured band is calculated by the following formula: bzxZ.net
Lwj=（Lpf- Kz-Kg） + 10lg
Formula: Lwr
Measurement report
Sound power level of the measured band, dB (reference value: 1pW); Average sound pressure level of each band of the measured virtual surface, dB (reference value: 20uPa), environmental correction value, αB,
Temperature and air pressure correction value, dB
Measurement surface area, m2,
Reference area, take S. =1 m2.
The name, model, specification and installation and operation of the woodworking machine tool to be measured, the measuring instrument used, the measurement environment and correction value, the measurement point layout, the measurement data and the calculation results should be listed in the woodworking machine tool noise measurement report form, see Appendix C Table C.1 to Table C.5. A.1 Absolute comparison method
GB 3770-—83
Appendix A
Determination of environmental correction value
(Supplement)
A.1.1 The standard sound source method can be divided into the substitution method, the mass placement method, the parallel method, the side placement method, etc. This standard recommends the standard sound source substitution method. That is, the woodworking machine tool under test is removed, and the standard noise source is placed at the geometric center of the original position of the woodworking machine tool under test for measurement. In unavoidable circumstances, the standard noise source can be placed at a location with a similar sound field to the woodworking machine tool under test for measurement. A.1.2 The environmental correction value can be calculated by the following formula: K, = Lw- Lwr
- environmental correction value, dB:
Formula 4 K2—
The A sound power level or frequency band sound power level measured by the standard noise source at the same measuring point as the tested woodworking machine tool, dB; - The calibrated A sound power level or frequency band sound power level Lyrr measured by the standard noise source according to JJG277-81 "Standard Sound Source Verification Procedure", dB.
A.2 Reverberation time method
The reverberation time method is mainly applicable to relatively regular rooms. The environmental correction value is calculated by the following formula: K=10lg (1 +
Where: Kz——environmental correction value, dB; S—measurement surface area, m2;
room sound absorption, m2,
room sound absorption A is measured by measuring the reverberation time of 1/1 octave band or 1/3 octave band and is obtained by the following formula: y
A=0.16 yuan
Where: A4—room sound absorption, m2
room volume, m,
T measured room frequency band reverberation time, s. K, the value can also be found from the following figure:
Kr= llg [1+-Ats]
304050
200300
GB3770—83
Method for synthesizing sound power level A in 1/1 octave band or 1/3 octave band sound power level (supplement)
Sound power level A synthesized from sound power level in 1/1 octave band or 1/3 octave band can be calculated by the following formula Lwa=1olgiou.i(whi+C,)
Where: L wA——A sound power level, dB (reference value: 1pW); Lwi-
-band power level of different center frequencies, dB (reference value: 1pW)-correction value of different center frequencies (given by meter B1), dB, representing the center frequency of each band. For 1/1 octave band jmax=7; for 1/3 octave band /max=21. Table B1
Center frequency
Center frequency
10 000
GB 3770-83
Appendix C
Noise measurement report for woodworking machine tools
(reference)
Table C.1 Noise measurement report for woodworking machine tools
Name of woodworking machine tools
Reference body size (m)
Distance between measuring plates
Installation and operation conditions of woodworking machine tools
Maximum speed (rpm)
Speed when maximum noise is generated (rpm)
Sound level meter
Measurement environment and woodworking machine tools Schematic diagram of location Filter
Model and specification
Measurement surface size (m)
Measurement surface area
Tool size
Motor power (kw)
Manufacture date
Microphone
Motor speed [rpm]
Schematic diagram of measurement surface and measurement point location
GB3770—83
Continued Table c.1
Description of the reflecting surface (ground, wall and other settings): Maximum city Schematic diagram of the level point and its location
Center frequency
Measurement unit
GB3770—83
Continued Table C.1
Signature of the measurer
Measurement date
Year, month, day
Condensation point
(P）m
GB3770—83
Sound power spectrum of woodworking machine noise
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++++++++++4 The sound power level of the measured band is calculated by the following formula:
Lwj=（Lpf- Kz-Kg） + 10lg
Formula: Lwr
Measurement report
frequency band sound power level, dB (reference value: 1pW); average sound pressure level of each frequency band of the measured virtual surface, dB (reference value: 20uPa), environmental correction value, αB,
temperature, air pressure correction value, dB
measurement surface area, m2,
reference area, take S. =1 m2.
The name, model, specification and installation and operation of the woodworking machine tool to be measured, the measuring instrument used, the measurement environment and correction value, the measurement point layout, the measurement data and the calculation results should be listed in the woodworking machine tool noise measurement report form, see Appendix C Table C.1 to Table C.5. A.1 Absolute comparison method
GB 3770-—83
Appendix A
Determination of environmental correction value
(Supplement)
A.1.1 The standard sound source method can be divided into the substitution method, the mass placement method, the parallel method, the side placement method, etc. This standard recommends the standard sound source substitution method. That is, the woodworking machine tool under test is removed, and the standard noise source is placed at the geometric center of the original position of the woodworking machine tool under test for measurement. In unavoidable circumstances, the standard noise source can be placed at a location with a similar sound field to the woodworking machine tool under test for measurement. A.1.2 The environmental correction value can be calculated by the following formula: K, = Lw- Lwr
- environmental correction value, dB:
Formula 4 K2—
The A sound power level or frequency band sound power level measured by the standard noise source at the same measuring point as the tested woodworking machine tool, dB; - The calibrated A sound power level or frequency band sound power level Lyrr measured by the standard noise source according to JJG277-81 "Standard Sound Source Verification Procedure", dB.
A.2 Reverberation time method
The reverberation time method is mainly applicable to relatively regular rooms. The environmental correction value is calculated by the following formula: K=10lg (1 +
Wherein: Kz——environmental correction value, dB; S—measurement surface area, m2;
room sound absorption, m2,
room sound absorption A is measured by measuring the reverberation time of 1/1 octave band or 1/3 octave band and is obtained by the following formula: y
A=0.16 yuan
Wherein: A4—room sound absorption, m2
room volume, m,
T measured room frequency band reverberation time, s. K, the value can also be found from the following figure:
Kr= llg [1+-Ats]
304050
200300
GB3770—83
Method for synthesizing sound power level A in 1/1 octave band or 1/3 octave band sound power level (supplement)
Sound power level A synthesized from sound power level in 1/1 octave band or 1/3 octave band can be calculated by the following formula Lwa=1olgiou.i(whi+C,)
Where: L wA——A sound power level, dB (reference value: 1pW); Lwi-
-band power level of different center frequencies, dB (reference value: 1pW)-correction value of different center frequencies (given by meter B1), dB, representing the center frequency of each band. For 1/1 octave band jmax=7; for 1/3 octave band /max=21. Table B1
Center frequency
Center frequency
10 000
GB 3770-83
Appendix C
Noise measurement report for woodworking machine tools
(reference)
Table C.1 Noise measurement report for woodworking machine tools
Name of woodworking machine tools
Reference body size (m)
Distance between measuring plates
Installation and operation conditions of woodworking machine tools
Maximum speed (rpm)
Speed when maximum noise is generated (rpm)
Sound level meter
Measurement environment and woodworking machine tools Schematic diagram of location Filter
Model and specification
Measurement surface size (m)
Measurement surface area
Tool size
Motor power (kw)
Manufacture date
Microphone
Motor speed [rpm]
Schematic diagram of measurement surface and measurement point location
GB3770—83
Continued Table c.1
Description of the reflecting surface (ground, wall and other settings): Maximum city Schematic diagram of the level point and its location
Center frequency
Measurement unit
GB3770—83
Continued Table C.1
Signature of the measurer
Measurement date
Year, month, day
Condensation point
(P）m
GB3770—83
Sound power spectrum of woodworking machine noise
++++++++++++++*+++++++
++ +++++++++++++++++++++++++++++++
++++++++++
++++++
+++++++
++++++++++ +++++++
++++++++
++++++++
++++++++
++++++
+++++++++
++++++++++4 The sound power level of the measured band is calculated by the following formula:
Lwj=（Lpf- Kz-Kg） + 10lg
Formula: Lwr
Measurement report
frequency band sound power level, dB (reference value: 1pW); average sound pressure level of each frequency band of the measured virtual surface, dB (reference value: 20uPa), environmental correction value, αB,
temperature, air pressure correction value, dB
measurement surface area, m2,
reference area, take S. =1 m2.
The name, model, specification and installation and operation of the woodworking machine tool to be measured, the measuring instrument used, the measurement environment and correction value, the measurement point layout, the measurement data and the calculation results should be listed in the woodworking machine tool noise measurement report form, see Appendix C Table C.1 to Table C.5. A.1 Absolute comparison method
GB 3770-—83
Appendix A
Determination of environmental correction value
(Supplement)
A.1.1 The standard sound source method can be divided into the substitution method, the mass placement method, the parallel method, the side placement method, etc. This standard recommends the standard sound source substitution method. That is, the woodworking machine tool under test is removed, and the standard noise source is placed at the geometric center of the original position of the woodworking machine tool under test for measurement. In unavoidable circumstances, the standard noise source can be placed at a location with a similar sound field to the woodworking machine tool under test for measurement. A.1.2 The environmental correction value can be calculated by the following formula: K, = Lw- Lwr
- environmental correction value, dB:
Formula 4 K2—
The A sound power level or frequency band sound power level measured by the standard noise source at the same measuring point as the tested woodworking machine tool, dB; - The calibrated A sound power level or frequency band sound power level Lyrr measured by the standard noise source according to JJG277-81 "Standard Sound Source Verification Procedure", dB.
A.2 Reverberation time method
The reverberation time method is mainly applicable to relatively regular rooms. The environmental correction value is calculated by the following formula: K=10lg (1 +
Wherein: Kz——environmental correction value, dB; S—measurement surface area, m2;
room sound absorption, m2,
room sound absorption A is measured by measuring the reverberation time of 1/1 octave band or 1/3 octave band and is obtained by the following formula: y
A=0.16 yuan
Wherein: A4—room sound absorption, m2
room volume, m,
T measured room frequency band reverberation time, s. K, the value can also be found from the following figure:
Kr= llg [1+-Ats]
304050
200300
GB3770—83
Method for synthesizing sound power level A in 1/1 octave band or 1/3 octave band sound power level (supplement)
Sound power level A synthesized from sound power level in 1/1 octave band or 1/3 octave band can be calculated by the following formula Lwa=1olgiou.i(whi+C,)
Where: L wA——A sound power level, dB (reference value: 1pW); Lwi-
-band power level of different center frequencies, dB (reference value: 1pW)-correction value of different center frequencies (given by meter B1), dB, representing the center frequency of each band. For 1/1 octave band jmax=7; for 1/3 octave band /max=21. Table B1
Center frequency
Center frequency
10 000
GB 3770-83
Appendix C
Noise measurement report for woodworking machine tools
(reference)
Table C.1 Noise measurement report for woodworking machine tools
Name of woodworking machine tools
Reference body size (m)
Distance between measuring plates
Installation and operation conditions of woodworking machine tools
Maximum speed (rpm)
Speed when maximum noise is generated (rpm)
Sound level meter
Measurement environment and woodworking machine tools Schematic diagram of location Filter
Model and specification
Measurement surface size (m)
Measurement surface area
Tool size
Motor power (kw)
Manufacture date
Microphone
Motor speed [rpm]
Schematic diagram of measurement surface and measurement point location
GB3770—83
Continued Table c.1
Description of the reflecting surface (ground, wall and other settings): Maximum city Schematic diagram of the level point and its location
Center frequency
Measurement unit
GB3770—83
Continued Table C.1
Signature of the measurer
Measurement date
Year, month, day
Condensation point
(P）m
GB3770—83
Sound power spectrum of woodworking machine noise
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++ +++++++++++++++++++++++++++++++
++++++++++
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++++++++++ +++++++
++++++++
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++++++++++1 Woodworking machine noise measurement report
Woodworking machine name
Benchmark body size (m)
Measuring plate distance
Woodworking machine installation and operation status
Maximum speed (rpm)
Speed when the maximum noise is generated (rpm)
Sound level meter
Measurement environment and woodworking machine location diagramFilter
Model and specification
Measurement mouse surface size (m)
Measuring surface area
Tool size
Motor power (kW)
Date of manufacture
Microphone
Motor speed [rpm]
Schematic diagram of measuring surface and measuring point location
GB3770—83
Continued Table c.1
Description of reflecting surface (ground, wall and other settings): Schematic diagram of the largest city-level point and its location
Center frequency||tt| |Measurement unit
GB3770—83
Continued Table C.1
Signature of measurer
Measurement date
Year/month/day
Condensation point
(P）m
GB3770—83
Sound power spectrum of woodworking machine tool noise
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++++++++++++++++ +++++++++++++++++++
++++++++
++++++
++++++++
++++++++++++++++
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+++++++++1 Woodworking machine noise measurement report
Woodworking machine name
Benchmark body size (m)
Measuring plate distance
Woodworking machine installation and operation status
Maximum speed (rpm)
Speed when the maximum noise is generated (rpm)
Sound level meter
Measurement environment and woodworking machine location diagramFilter
Model and specification
Measurement mouse surface size (m)
Measuring surface area
Tool size
Motor power (kW)
Date of manufacture
Microphone
Motor speed [rpm]
Schematic diagram of measuring surface and measuring point location
GB3770—83
Continued Table c.1
Description of reflecting surface (ground, wall and other settings): Schematic diagram of the largest city-level point and its location
Center frequency||tt| |Measurement unit
GB3770—83
Continued Table C.1
Signature of measurer
Measurement date
Year/month/day
Condensation point
(P）m
GB3770—83
Sound power spectrum of woodworking machine tool noise
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++++++++++++++++ +++++++++++++++++++
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