This standard briefly summarizes the basic standards for determining the emission sound pressure levels at the working position and other designated positions of various types of machines and equipment, and provides guidance on how to select the corresponding basic standards according to the type of machines and equipment. This guideline applies to the preparation of noise test procedures, and also applies to noise testing in the absence of noise test procedures, but only applies to airborne sound. GB/T 17248.1-2000 Acoustics Guidelines for the use of basic standards for determining the emission sound pressure levels at the working position and other designated positions of noise emitted by machines and equipment GB/T17248.1-2000 Standard download decompression password: www.bzxz.net
This standard briefly summarizes the basic standards for determining the emission sound pressure levels at the working position and other designated positions of various types of machines and equipment, and provides guidance on how to select the corresponding basic standards according to the type of machines and equipment. This guideline applies to the preparation of noise test procedures, and also applies to noise testing in the absence of noise test procedures, but only applies to airborne sound.

GB/T 17248. 1—2000
This standard is equivalent to the international standard ISO11200:1995 "Noise emitted by acoustic machines and equipment - Guidelines for the use of basic standards for the determination of emission sound pressure levels at working positions and other specified positions". This standard is the first standard in the GB/T17248.1~17248.5 series of standards, which include: Noise emitted by acoustic machines and equipment - Guidelines for the use of basic standards for the determination of emission sound pressure levels at working positions and other specified positions GB/T17248.1
Guidelines for the use of basic standards
Noise emitted by acoustic machines and equipment - Measurement of emission sound pressure levels at working positions and other specified positions - Engineering method for approximating free fields above a reflecting surface GB/T17248.3||t t||Noise emitted by acoustic machines and equipment. Field simplified method for measuring the emission sound pressure level at working position and other designated positions
GB/T17248.4 Noise emitted by acoustic machines and equipment. Determination of emission sound pressure level at working position and other designated positions by sound power level
'Measurement of emission sound pressure level at working position and other designated positions GB/T17248.5 Noise emitted by acoustic machines and equipment. Environmental correction method
This series of standards specifies various methods for measuring the working position and other designated positions of machines and equipment. Appendix A of this standard is the appendix of the standard.
Appendix B of this standard is a prompt appendix for reference only. This standard is proposed by the Chinese Academy of Sciences.
This standard is under the jurisdiction of the National Technical Committee for Acoustics Standardization. The drafting unit of this standard: Institute of Acoustics, Chinese Academy of Sciences. The main drafters of this standard: Lv Yadong, Zhang Ruwei, Xu Xin. 341
GB/T17248.1--2000
ISOForeword
The International Organization for Standardization (ISO) is a worldwide federation of national standardization committees (ISO member states). The formulation of international standards is usually completed by ISO technical committees. Each member state has the right to participate in a technical committee when it is interested in a standard determined by a technical committee. Governmental and non-governmental international organizations associated with ISO may also participate in the work. The International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC) maintain close cooperation in all aspects of electrotechnical standardization. The draft international standards adopted by each technical committee shall be distributed to each member state for voting. The draft international standard requires at least 75% of the member states to vote in favor before it can be published as an international standard. International Standard ISO11200:1995 was drafted by ISO/TC43 Acoustics Technical Committee SC1 Noise Subcommittee. Appendix A of this standard is the standard appendix. Appendix B of this standard is indicative and for reference only. 342
National Standard of the People's Republic of China
AcousticsNoise emitted by machinery and equipment-Guidelines for the use of basic standards for thedetermination of emission sound pressure levels at a workstation and at other specified positionsGB/T 17248.1-2000
eqv ISO 11200:1995
0.1Noise control of machinery and equipment requires effective communication of acoustic information between manufacturers, installers and users of machinery and equipment. The relevant acoustic data are obtained by measurement. These measurement results are meaningful only when the measurements are made under specified measurement conditions using specified instruments and the determined acoustic quantities are measured.
Two complementary quantities are used to characterize the noise emission of machinery and equipment, one is the sound power level and the other is the emission sound pressure level at a specified position. GB/T3767, GB/T 3768, GB6881, GB6882, GB/T14367, GB/T16404, GB/T16404.2, ISO3743-1, ISO3743-2 specify the basic determination method of sound power level. This standard introduces four standards for different determination methods of emission sound pressure level of machinery and equipment. When the machinery and equipment are in the specified acoustic environment and perform the specified functions under the specified installation and operating conditions, the emission sound pressure level is the sound pressure level at one or more locations near the machinery and equipment. It only comes from the noise radiated by the machinery and equipment. Its operating and installation conditions are the same as the conditions for the determination of the sound power level. The positions referred to in this series of standards include: working positions (usually specified in the noise test procedures), positions occupied by one or more machine operators, and positions sometimes occupied by other personnel. These positions can be located in the operating room near the machine, or in some other enclosed spaces slightly away from the machine. The emission sound pressure level can be generated by a machine that works continuously in a steady state, or it can be an average value within a specified working cycle. When a machine performs different functions, operates under different control settings, or experiences changes in workload, the emission sound pressure level is not the average value for the entire working day. Emission sound pressure level and sound power level can be used to calibrate the noise emitted by machinery and equipment under specified conditions, verify calibration values, compare the noise emitted by machines of various models and specifications, compare with the limits specified in sales contracts or regulations, and can be used for engineering projects to reduce machine noise emissions and estimate noise exposure at specified locations. For many products, sound power level is the main indicator for comparing noise emissions. Noise test procedures and special instructions procedures should explain the main indicators used for comparison.
This series of standards includes three standards (GB/T17248.2, GB/T17248.3, GB/T17248.5) that directly measure emission sound pressure levels under different test environments and a fourth standard (GB/T17248.4) that determines emission sound pressure levels by sound power. When using these standards for specific machine noise measurements, the most appropriate standard for the specific type of machine equipment and test purpose must be selected. To this end, this standard provides the relevant selection guidelines for the series of standards. 0.2 This standard, as a guide, constitutes a series of standards together with GB/T17248.2~17248.5. In principle, the methods specified in GB/T17248.2~17248.5 cover all types of machinery and equipment. For noise measurement of a specific type and size of machinery and equipment, or when there are certain practical restrictions, only one of these standards can be applied. GB/T17248.2~~17248.5 constitute the basic standards for determining the emission sound pressure level. These standards specify the acoustic conditions and the instruments to be used, and explain the procedures to be followed, and give general requirements for the installation and operation of the measured machine. In general, because the environment affects the emission sound pressure level, these emission sound pressure levels are different from the noise generated by the operation of machinery and equipment in normal environment. For practical reasons, the choice of the standard for measuring the sound power level will affect the choice of the standard for measuring the emission sound pressure level. Here, priority should be given to those standards that can take into account both noise emission characterization quantities.
0.3 This standard is one of a series of standards, which specifies various methods for measuring the noise emission of machinery and equipment and the components of the machinery and equipment being measured. The series of standards are divided into the following three categories:
1) Methods for measuring the emission sound pressure level at working positions and other specified positions In addition to this standard, this category includes the following standards (see Table 1): -GB/T17248.2 gives an engineering method for measuring the emission sound pressure level of machinery and equipment in an approximately free field above a reflecting surface. This method does not make environmental corrections.
GB/T17248.3 gives a simple method for on-site measurement of the emission sound pressure level of machinery and equipment, using a simplified method for environmental correction. GB/T17248.4 gives two different methods for measuring the emission sound pressure level of machinery and equipment by sound power level. -GB/T17248.5 gives the method for measuring the emission sound pressure level of machinery and equipment, which can obtain engineering-level or simple-level measurement results. Table 1 Summary of standards for measuring emission sound pressure levels at working positions and other specified positions Classification Items
Test environment
Test environment applicable criteria
Sound source size
Noise characteristics
Restriction on background noise
Emission sound pressure level measurement point
Instrument:
a) Sound level meter
b) Integrating sound level meter
c) Band filter
d) Calibrator
Measured quantity
At least meets
GB/T 17248. 2
Measurement method
Outdoor or indoor
K2A2 dB
GB/T 17248.3
Measurement method
Outdoor or indoor
K2A≤7dB
Unrestricted, limited only by test environment
Unrestricted, limited only by test environment
Environmental limitation
Any type (broadband, narrowband, discrete frequency, steady state, non-steady state, pulse)
AL\≥6dB (greater than 15dB if possible);
ALP≥3dB
Each specified location: K1AK1A3dB
≤1. 3 dB
Working position and other designated positions
a) Type 1 of GB3785
b) Type 1 of GB/T17181
lc) Type 1 of GB3241
d) Level 1 of GB/T15173
A-weighted sound level, C-weighted
Beep value sound level, preferred frequency band
Sound pressure level
a) Type 2
b) Type 2
e ) Level 1
d) Level 1
A-weighted sound level, C-weighted
Peak sound level
GB/T17248.4
Obtained from the sound power level
Level 2 or Level 3
Same as the sound power level measurement standard
Same as the sound power level measurement standard
Especially suitable for small batch production
Same as the sound power level measurement standard
Same as the sound power level measurement standard
GB/T 17248.5
Measurement method
Level 2 or 3
Outdoor or indoor
K2A≤7dB
Unlimited, limited only by the test environment
Any type
≥6B (greater than 15dB if possible);
Each designated position: K1A
Working position and other designated positions
Working position and other designated positions (but not in a workplace or similar environment
Same as the sound power level determination standard
Same as the sound power level determination standard
Designated position
[a) Type 1
b) 1 Type
e) Level 1
d) Level 1
A-weighted sound level, C-weighted
peak sound level, preferred frequency band
sound pressure level
approximately less than or equal to 2.5dB
Determine the accuracy of the LA method (expressed as approximately less than or equal to the sound power level measurement adopted" (accuracy level 2) or 5dB
reproducibility standard deviation)
Related sound power level standards
GB/T3767
GB/T3768
Accuracy obtained by the determination method
GB/T14367, GB/T3767
GB/T 3768.GB 6881.
GB 6882.GB/T 16538,
GB/T16404,
GB/T16404.2
1) △L is the difference between the sound pressure level measured when the sound source is in operation and the background noise level. 2) Considering that the equipment to which these standards apply differ greatly from each other, experimental recommended values ​​are given here 344
(Accuracy Grade 3)2)
GB/T3767 (Accuracy Grade 2)
GB/T 3768 (Accuracy Grade 3)
2) Methods for determining sound power levels
GB/T 17248. 1—2000
-GB/T14367 provides guidelines for selecting methods for determining the sound power radiated by machinery and equipment. GB/T3767, GB/T3768, GB6881, GB6882, and GB/T16538 provide various methods for determining the sound power level of machinery and equipment by sound pressure.
-GB/T16404 and ISO9614-2 describe methods for determining the sound power level of machinery and equipment by sound intensity. 3) Noise test procedures
For a specific series of machines and equipment, the noise test procedures should specify: - the method used to determine the sound power level; - the method used to determine the emission sound pressure level at the working position and other specified positions; - the orientation of the working position;
- the installation and operating conditions of the tested machine for determining the noise emission; the method used to verify the nominal amount of noise emission. 1 Scope
This standard briefly summarizes the various basic standards for determining the emission sound pressure level at the working position and other specified positions of various types of machines and equipment, and provides guidance on how to select the corresponding basic standards according to the type of machine and equipment. This guideline applies to the preparation of noise test procedures and also to noise testing in the absence of noise test procedures, but only applies to airborne sound. It is important to formulate and use noise test procedures for various types of machines and equipment that meet the requirements of these basic standards. These noise test procedures specify specific requirements for the installation and operating conditions of the tested machine products and the working position and other specified positions specified in the standard. The obtained data can be used for the nominal and verification of the emission sound pressure level specified in GB/T14574. Note 1: At any given location, installation and operating conditions related to a specific machine, the emission sound pressure level measured according to any method of GB/T17248.2 to 17248.5 is generally lower than the sound pressure level of the same machine measured directly in a typical workplace. This is due to the influence of reverberation and other machines. For the calculation method of the sound pressure level near a machine running alone in a workplace, refer to ISO/TR 11690-3. Generally, the difference between the two is 1 to 5 dB, and the difference is greater in some cases. 2 Reference standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard was published, the versions shown were valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T3102.7-1993 Acoustic quantities and units GB/T3241-1998 Octave-band and fractional-octave-band filter acoustics Determination of the sound power level of noise sources by the sound pressure method Engineering method for approximate free field above the reflecting surface GB/T3767-1996#
GB/T3768-1996
Acoustics Determination of the sound power level of noise sources by the sound pressure method A simplified method using an envelope measuring surface above the reflecting surface GB/T 3785-1983
Electrical and acoustic properties and test methods of sound level meters GB/T3947--1996 Terminology of acoustics
GB/T 6881-1986
GB/T 6882-1986
GB/T 14259-1993
GB/T 14367-1993
GB/T 14574--2000
GB/T 15173—1994
GB/T 16404-1996
Determination of sound power level of noise source Precision method and engineering method in reverberation chamber Determination of sound power level of noise source Precision method in anechoic chamber and semi-anechoic chamber Acoustics
Guide to standards for the measurement of airborne noise and the assessment of its impact on people Determination of sound power level of noise source Guidelines for the use of basic standards and the formulation of noise test specifications Acoustics Indication and verification of noise emission values ​​of machines and equipment Acoustic calibrator
Acoustics Determination of sound power level of noise source by sound intensity method Part 1: Measurement at discrete points GB/T16404.2—1999
Acoustics Determination of sound power level of noise source by sound intensity method Part 2: Scanning measurement method GB/T16538—1996 Acoustics Determination of sound power level of noise source by sound pressure method Using standard sound source Simple method 345
GB/T 17181-
—1997
GB/T 17248.1—2000
Integrating average sound level meter
GB/T 17248.2—1999
Noise emitted by machines and equipment Sound pressure level at work and other specified locations Acoustics
Engineering method for approximate free field above a reflecting surface GB/T17248.3—1999 Acoustics
Noise emitted by machines and equipment Sound pressure level at work and other specified locations Simple field method
GB/T 17248. 4--1998
Noise emitted by machines and equipment Determination of emission sound pressure levels at work and other specified locations by sound power level
9 Acoustics Noise emitted by machines and equipment Emission sound pressure levels at work and other specified locations GB/T17248.5-1999
Measurement environment correction method
ISO3743-1:1994 Acoustics - Determination of sound power levels of noise sources by sound pressure method - Engineering method for small, movable sound sources in a reverberant field - Part 1: Comparison method between hard-walled testers
ISO3743-2:1994 Acoustics - Determination of sound power levels of noise sources by sound pressure method - Small, movable sound sources in a reverberant field Engineering methods for portable sound sources - Part 2: Methods for special reverberation test rooms
ISO7779:1988 Acoustics - Measurement of airborne sound radiated by computers and business equipment ISO/TR11690-3:1997 Acoustics - Recommended practices for the design of low-noise workplaces containing machines - Part 3: Sound propagation and noise prediction in workplaces
ISO12001:1996 Acoustics - Noise emitted by machines and equipment - Drafting of noise test procedures and criteria for their presentation 3 Definitions
This standard adopts the following definitions. Other acoustic terms, quantities and units are in accordance with the provisions of GB/T3947 and GB/T3102.7. 3.1 Emission
Airborne sound is radiated by a certain sound source (the machine under test). Note 2: The noise emission characterization quantity can be included in the product label or product manual. The basic noise emission characterization quantity is the sound power level of the sound source and the emission sound pressure level at the working position and other specified positions (if any) near the sound source. 3.2 Emission sound pressure p emission sound pressure p sound pressure at a specified position near a sound source working under specified installation and operating conditions on a reflecting plane. It does not include the background noise and the influence of other sound reflections outside the reflecting surface allowed by this test method, Pa. 3.3 Emission sound pressure level L, emission sound pressure level L, the logarithm of the ratio of the square of the emission sound pressure p(t) to the square of the reference sound pressure p multiplied by 10. Measured using the time weighting and frequency weighting specified in GB/T3785, dB. The reference sound pressure po is 20μPa. Note 3: For example:
F time-weighted maximum A-weighted emission sound pressure level LpAFmax - C-weighted peak emission sound pressure level LpC.peak. Where: p\(t) represents the square of the effective value of the sound pressure changing with time. The emission sound pressure level should be measured at the specified position, and its position should comply with the noise test procedures for machinery and equipment; if there is no corresponding test procedure, the method used should comply with the provisions of the GB/T17248.1~17248.5 series of standards. 3.4 Sound power W sound power W
The sound energy passing through a certain area per unit time, in watts, W. 3.5 Sound power level Lwsound power level LuwThe logarithm of the ratio of sound power to reference sound power with base 10, in bels, B. However, αB is usually used as the unit. The reference sound power is 1pW.
Note 4: For example: A-weighted sound power level is LwA. 3.6 Time-averaged emission sound pressure level Lpeq7time-averaged emission sound pressure level Lpeg7In the measurement time T, the mean square sound pressure of a noise signal that varies with time is equal to the square of the sound pressure of the continuous steady-state sound in the same time, then the sound pressure level of the continuous steady-state sound is the time-averaged emission sound pressure level, dB. Expressed by formula (1)346
GB/T 17248. 1—2000
pdt dB
Lmar = 10 g ). p
A-weighted time-averaged emission sound pressure level is expressed as LpAegT, which can be abbreviated as LpA. Its measuring instrument should comply with the key points of GB/T17181 standardbzxZ.net
5In general, since the time-averaged emission sound pressure level must be measured within a certain measurement time, the subscripts eq and T can be omitted. 6 Formula (1) is the same as the expression of the environmental noise characterization quantity "equivalent continuous sound pressure level" defined in GB/T3222 standard. However, the emission quantity defined in this standard is used to characterize the noise emission of the machine under test, and it is assumed that the measurement is carried out under standard measurement and operating conditions and a limited acoustic environment. 3.7 Workstation, operators position workstation, operatorsposition The position designated for the operator near the machine under test. 3.8 Operator operator
Personnel engaged in machine-related work tasks near the machine under test. 3.9 Specified position specified position The position related to the machine, including but not limited to the operator position. The position can be a single fixed point, or several points on a path, or several points on a surface at a specified distance from the machine. Note 7: A specified position near the workstation or near an unattended machine can be used as a "bystander position". 3.10 Background noise background noise The noise of all sound sources other than the machine under test. Note 8: Background noise should include air noise, structure-borne noise, and instrument electrical noise. 3.11 Background noise level background noise level The sound pressure level measured when the machine under test is not working, dB. 3.12 Background noise correction K, background noise correction K, this correction term is used to indicate the influence of background noise on the emission sound pressure level at the specified position of the machine under test, K, is related to frequency, dB. The correction term K1A in the A-weighted case is obtained from the A-weighted measurement value. 3.13 Environmental indicator K2 This correction term is used to indicate the influence of reflected or absorbed sound on the surface sound pressure level, K, is related to frequency, dB. In the A-weighted case, it is represented by K2A (see GB/T3767.GB/T3768). 3.14 Local environmental correction K, local environmental correction K: This correction term is used to indicate the influence of reflected sound on the emission sound pressure level at the specified position of the machine under test (such as the working position), dB. K: is related to frequency and position. In the A-weighted case, it is represented by K3A. 4 Selection of standards for determining emission sound pressure levels
4.1 General requirements
The same installation and operating conditions should be used to determine emission sound pressure levels and sound power levels. The noise test procedures for machinery and equipment should provide detailed information on installation, layout and operating conditions.
Note 9: For desktop equipment, the noise test procedures may not require the same installation, layout and operating conditions. Such equipment can be placed on the floor to measure sound power.
4.2 Measured quantities and quantities to be determined
GB/T17248.2~17248.5 give methods for determining emission sound pressure levels. Sound levels can be specified as time average, peak frequency weighting, frequency band or time weighting. In addition to the peak sound level, C weighting is preferred, and frequency weighting generally uses A weighting. 4.3 Factors affecting the selection of methods
When selecting a standard from this series of standards, the following factors should be considered: a) the size and transportability of the machine or equipment, which will affect the feasibility of its installation in the acoustic test laboratory; b) whether the working position related to the machine is specified; c) the test environment suitable for measurement;
d) the accuracy level required.
GB/T 17248. 1—2000
Note 10: For noise calibration measurement methods, the engineering method (accuracy level is Class 2) is preferred. 4.4 Summary
For the summary of GB/T.17248.2~17248.5, see Appendix A. Table 1 gives an overview of the various standards for determining the emission sound pressure level at the working position and other specified positions.
4.5 Selection steps
In principle, GB/T17248.2~17248.Each of the methods described in 5 for determining the emission sound pressure level is suitable for all types of machinery and equipment. The choice of method is determined by technical and practical constraints. General guidelines for the selection of methods are given below. The guidelines make the selection of different methods easy and quick. See the flow chart (see Figure 1). The scope of application of several methods is shown in Figure 2. Is the machine operator involved? Is the working position determinable? Can on-site measurements be carried out? Describe as a path or surface. Can it be measured in a semi-anechoic room? Or use a correction between sound power level and sound pressure level. Is a high level of accuracy required?
Level 2 method
Measurement at a designated location + background noise
Using GB/T 17248.2
"Correction KIA+Environmental correction K2A
Level 2 or Level 3 method
Measurement at a designated location + background noise correction
Using GB/T 17248.5
Correction K,A+Environmental correction KA+Local
Environmental correction K3A
Level 3 method
Using GB/T 17248.3,
Using GB/T17248.4
Using Q1
Using GB/T 17248.4
Use Q2
Measurement at a specified location + background noise correction. K,A+environmental correction KA+local
environmental correction K3A
Level 1, 2 or 3 force method
Depending on the sound power measurement standard used
Figure 1 Flowchart for guiding the selection of the standard for measuring the emission sound pressure level of machine equipment K2A-dB
Cannot be measured according to this series of standards
GB/T 17248.3 (Level 3)
GB/T 17248. 2
（Level 2）
GB/ T 17248. 3
（Level 3）
GB/T 17248. 5
(Level 2 or Level 3
Depends on K3A)
GB/T 17248. 3
(Level 3)
GB/T 17248.5
(Level 2 or Level 3
Depends on K3A)
Figure 2 Application scope of GB/T17248.2, GB/T17248.3 and GB/T17248.5 (In the figure: △L is the difference between the measured sound pressure level and the background noise level, K2A is the environmental correction) 318
4.5.1GB/T 17248.2
GB/T17248.1—2000
This standard specifies an engineering measurement method and is suitable for machines that meet the following requirements [a), b) and c). a) The machine usually works in a nearly free field near one or more reflecting surfaces, so on-site noise testing can be carried out; or the machine is movable and can be installed in the above-mentioned nearly free field conditions allowed for noise testing; b) The machine is installed under conditions where the background noise and test environment can meet the specified requirements without environmental correction; c) The machine has one or more working positions or other designated positions. 4.5.2GB/T 17248.3
This standard specifies a simple measurement method and is suitable for machines that meet the following requirements [a), b) and c). a) The machine cannot be installed in a nearly free field above a reflecting surface allowed for measurement purposes; b) The machine is installed under conditions where the background noise and test environment can meet the specified requirements and simple environmental correction can be carried out; c) The machine has one or more working positions or other designated positions. 4.5.3GB/T17248.4
This standard specifies methods for determining the emission sound pressure level from the sound power level. The accuracy obtained by these methods is the same as that obtained by the sound power level determination method and is suitable for machines that meet the following requirements [a) to d). a) Machines for which the sound power level can be obtained under appropriate installation and operating conditions; b) Machines that do not have a certain working position;
c) Machines that have one of the following conditions:
1) The corresponding relationship between the sound power level and the emission sound pressure level at certain specified positions has been established through experiments; 2) The working position can be represented as a point or path on a certain machine envelope surface (the measurement surface used to determine the sound power level); d) The machine radiation is non-directional, or the machine is usually close to a wall. 4.5.4GB/T17248.5
This standard specifies a measurement method, the accuracy obtained by this method (engineering grade or simple grade) depends on the measurement environment, and is suitable for machines that meet the following requirements [a), b) and c]. a) The machine cannot be installed in a nearly free field above a reflecting surface allowed for the measurement purpose; b) The machine is installed under conditions where the background noise and test environment meet the specified requirements and a more accurate environmental correction than GB/T17248.3 can be performed;
c) The machine has one or more specific working positions or other specified positions. 5 Selection of specified positions
5.1 Specified positions
This standard applies to working positions and other specified positions where the emission sound pressure level is to be measured. Some examples of positions where measurements can be made are as follows: a) Working position near the machine being measured, which is the case for many industrial machines and household appliances; b) Working position in the operating room, which is an integral part of the machine being measured. This is the case for many trucks and earth-moving machinery.
c) a working position in a partially or fully enclosed space (or behind a barrier) which is an integral part of the machine equipment provided by the manufacturer.
d) a working position in a partially or fully enclosed space for the machine being tested, which is the case for some large industrial machines.
e) a bystander position not responsible for operating the machine.
f) other specified positions, not necessarily working positions or bystander positions.5.2 Microphone positions for bystanders and unattended machinesIf no operator position is specified, a "customary" working position (i.e. for maintenance, service or repair) or one or more bystander positions may be defined and described in the noise test procedure. 319
GB/T 17248. 1--2000
If no noise test procedure is available, measurements may be made at four or more microphone positions at a height of 1.550 m ± 0.075 m above the ground and 1 m outside the reference body defined in GB/T3767 or GB/T3768. Record the maximum emission sound pressure level as the emission sound pressure level of the machine under test, and record its measurement position.
Instead of using discrete positions, the method of calculating the surface sound pressure level from the sound power level is adopted in accordance with GB/T17248.4, and the result also meets requirement 11
Some noise test procedures require that the average value of four or more positions be recorded as the emission sound pressure level of the machine under test, as shown in ISO7779. 5.3 Working position in the operating room
If the working position or bystander position of the machine is located in the operating room or workshop, the "customary\working position or bystander position" added outside the operating room or workshop (for maintenance) near the machine under test should be specified in the noise test procedure. 350
GB/T 17248. 1—2000
Appendix A
(Appendix to the standard)
Summary of the standard for measuring emission sound pressure level
A1GB/T17248.2—1999 Acoustics Noise emitted by machines and equipment Measurement of emission sound pressure level at working position and other specified positions Engineering method of approximately free field above a reflecting surface A1.1 Applicability
a) Test environment: The type of test environment affects the measurement accuracy of the emission sound pressure level. This standard requires an approximately free field above a reflecting surface;
b) Noise source type: Any noise source used indoors or outdoors Any fixed or mobile sound source; c) Noise source size: unlimited;
d) Characteristics of noise radiation from the sound source: various types of noise defined in GB/T14259 and ISO12001. A1.2 Measurement uncertainty
Since it is impossible to give a widely applicable value for the standard deviation of the repeatability of the emission sound pressure level at the working position, please refer to Chapter 4 of GB/T17248.2 for specific guidance.
A1.3 Emission sound pressure level to be measured (A-weighted, and if necessary, C-weighted peak and band sound pressure levels). A2GB/T17248.3—1999 Acoustics Noise emitted by machines and equipment Measurement of emission sound pressure levels at work and other specified locations Field simplified method
Applicability
a) Test environment: indoor or outdoor environment with one or more reflecting surfaces that meet specific requirements; b) Type of noise source: fixed or mobile sound source used indoors or outdoors; c) Noise source size: no restrictions;
d) Characteristics of noise radiation from sound sources: various types of noise defined in GB/T14259 and ISO12001. A2.2 Measurement uncertainty
Since it is impossible to give a widely applicable value for the standard deviation of the reproducibility of emission sound pressure levels at work, specific guidance is provided in Chapter 4 of GB/T17248.3.
A2.3 Emission sound pressure level to be measured (A-weighted, and if necessary, C-weighted peak and band sound pressure levels). A3GB/T17248.4--1998 Acoustics Noise emitted by machines and equipment is measured by sound power level Emission sound pressure level at working position and other specified positions
A3.1 Applicability
a) Test environment: an environment that can measure the sound power level in accordance with GB/T14367 or GB/T16404 series standards; b) Noise source type: a fixed or mobile sound source used indoors or outdoors, especially for mass production; c) Noise source size: preferably a small size sound source; sound.
d) Characteristics of noise radiation from the sound source: various types of noise defined in GB/T14259 and ISO12001 that conform to the sound power level measurement method A3.2 Measurement uncertainty
The same as the value specified in the sound power level measurement method. 351
A3.3 To be measured
GB/T 17248. 1-2000
The emission sound pressure level measured with the same frequency weighting and time weighting as the sound power level, and the same bandwidth. A4GB/T17248.5-1999 Acoustics Noise emitted by machines and equipment Measurement of emission sound pressure level at working position and other specified positions Environmental correction method
A4.1 Applicability
a) Test environment: Indoors or outdoors with one or more reflective surfaces that meet specific requirements; b) Type of noise source: Fixed or mobile sound source used indoors or outdoors; c) Noise source size: Unlimited;
d) Characteristics of noise radiation from sound source: Meet all types of noise in GB/T14259 and ISO12001. A4.2 Measurement uncertainty
Since it is not possible to give a widely applicable value for the standard deviation of the repeatability of the emission sound pressure level at the working position, please refer to Chapter 4 of GB/T 17248.5 for specific guidance.
To be measured
Emission sound pressure level (A-weighted, and if necessary, C-weighted peak and band sound pressure levels). Appendix B
(Suggestive Appendix)
References
ISO 1996-l:1982 Acoustics—Description and measurement of environmental noise-Part l: Basic quantities and procedures
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