Acoustics--Noise emitted by machinery and equipment--Determination of emission sound pressure level at a workstation and at other specified position from the sound power level
Some standard content:
GB/T17248.4—1998
This standard is equivalent to the international standard ISO11203:1995 "Acoustics - Noise emitted by machines and equipment - Determination of emission sound pressure levels at work positions and other designated positions from sound power levels", which is part of the ISO11200 series of standards. This standard is the fourth standard in the GB/T17248.1~17248.5 series of standards, which include: GB/T17248.1 Acoustics - Noise emitted by machines and equipment - Criteria for the use of basic standards for determining emission sound pressure levels at work positions and other designated positions
Acoustics - Noise emitted by machines and equipment - Measurement of emission sound pressure levels at work positions and other designated positions - GB/T 17248.2
Engineering method for approximate free field above a reflecting surface GB/T17248.3 Noise emitted by acoustic machines and equipment. On-site simplified method for measuring the emission sound pressure level at the working position and other designated positions
GB/T17248.4 Noise emitted by acoustic machines and equipment. The emission sound pressure level at the working position and other designated positions is determined by the sound power level
GB/T17248.5 Noise emitted by acoustic machines and equipment. Environmental correction method for measuring the emission sound pressure level at the working position and other designated positions
This series of standards specifies in detail various methods for measuring the emission noise of a machine or equipment or the parts of the equipment to be tested: This series of standards guides and lists a variety of options to determine the emission sound pressure level of the machine. At the same time, this standard also lists the national standards and international standards for the determination of sound power level. Appendix A of this standard is a suggestive appendix. This standard is proposed and managed by the National Technical Committee for Acoustic Standardization. Drafting unit of this standard: Shanghai Electric Science Research Institute, Ministry of Machinery. The main drafters of this standard are Chen Yeshao and Shi Qingyuan. This standard shall be implemented from October 1, 1998. 386
GB/T17248.4--1998
ISOForeword
The International Organization for Standardization (ISO) is a worldwide joint organization composed of national standardization committees (ISO member countries). The formulation of international standards is usually completed by ISO technical committees. Each member country has the right to participate in the 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. 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 circulated to each member country for voting. The draft international standard requires at least 75% of the member countries to vote in favor before it can be published as an international standard. ISO11203 was drafted by ISO/TC43 Acoustics Technical Committee, SC1 Noise Subcommittee. Appendix A of this international standard is indicative. 387
0 Introduction
National Standard of the People's Republic of China
Noise emitted by machinery and equipment
Determination of emission sound pressure levelat a workstation and at other specifiedposition from the sound power level
Acoustics--Noise emitted by machinery and equipment -Determination of emission sound pressure levelat a workstation and at other specifiedposition from the sound power levelGB/T17248.4—1998
eqyIS11203:1995
This standard specifies in detail how to determine the emission sound pressure level at the nearby workstation or other specified position from the sound power level of machinery and equipment. These sound pressure levels are different from those when the machinery and equipment are operating under normal environmental conditions, because the on-site operation is affected by the surrounding environment.
·1 Scope
1.1 Overview
This standard specifies two methods for calculating the sound pressure level emitted by machines and equipment at the working position or specified position near the machine and equipment based on the sound power level. Its main purpose is to compare the noise performance of machines and equipment of the same type but different specifications under given environmental conditions and specified installation and operating conditions. The results can be used to express and verify the emission sound pressure level specified in ISO4871. The determination of the emission sound pressure level should use the same frequency and time weighting, or the same frequency band as the sound power level test. Note
1 A summary of international standards related to the above content can be found in Table 1 of ISO11200:1995. 2 The emission sound pressure level determined by this standard for the machine, at any given location, under specified installation and operating conditions, is generally lower than the sound pressure level directly measured when the machine is actually running in the factory. This is because the site is affected by other machines and sound field conditions, while ISO11690-3 provides a method for calculating the emission sound pressure level of a single machine when it is running in a studio. Generally speaking, the difference should be between 1 and 5 dB, and the difference is greater in special cases.
1.2 Types of noise and noise sources
This standard applies to all kinds of machines, including fixed or non-fixed, indoor or outdoor, especially mass-produced machines. However, the method of this standard is not applicable to outdoor strongly directional sound sources. This standard is particularly applicable to machines with a length, width and height of less than or equal to 1m. In some cases, it is also applicable to larger machines (see 6.2.3).
This standard applies to all types involved in the noise sound power level test methods in GB/T14259 and ISO12001. 1.3 Test environment
The environment used is consistent with the environment used in all series of standards such as GB/T14367 or GB/T16404. 1.4 Designated position
This standard is used to determine the emission sound pressure level at the working position or designated position near the sound source under test, rather than the working position or designated position behind the barrier in the carriage or cabin.
GB/T 17248. 4-1998
For a standing or sitting worker at the designated position, the working position can be a point or a passage. Note 3: For detailed provisions on standing, sitting, stationary, walking operators or other persons present, please refer to the international standard ISO11201. 1.5 Provisions for the application of each method
For the application provisions of the two methods of this standard, please refer to 6.2.2 and 6.2.3. 2 Referenced standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. At the time of publication of the standard, the versions shown are valid. All standards are subject to revision, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T3767-1996 Acoustics Sound pressure method for determining the sound power level of noise sources Engineering method for approximate free field above the reflecting surface GB/T3768-1996 Acoustics Sound pressure method for determining the sound power level of noise sources Simple method using envelope measurement surface above the reflecting surface GB3785--83 Electrical and acoustic properties and test methods of sound level meters GB6881-86 Determination of sound power level of acoustic noise sources Precision method and engineering method in reverberation chamber GB6882-86 Determination of sound power level of acoustic noise sources Precision method in anechoic chamber and semi-anechoic chamber GB/T14259--93 Acoustics Guide to the measurement of airborne noise and the evaluation standard of its impact on humans GB/T14367--93 Determination of sound power level of acoustic noise sources Guidelines for the use of basic standards and the formulation of noise test specifications GB/T15173--94 Sound calibrator||tt ||GB/T16404-1996 Acoustics - Determination of sound power level of noise source by sound intensity method - Part 1: Measurement at discrete points ISO9614-2:1996 Acoustics - Determination of sound power level of noise source by sound intensity method - Part 2: Scanning measurement method ISO11200:1995 Acoustics - Noise emitted by machines and equipment - Criteria for the use of basic standards for determining emission sound pressure levels at working positions and other specified locations
ISO12001:1997 Acoustics - Noise emitted by machines and equipment IEC804:1985 Integrating average sound level meter
Drafting of noise test procedures and the criteria proposed IEC1260;1996 Electroacoustics -
Octave and fractional octave filters
3 Definitions
This standard adopts the following definitions:
3.1 Emission
The airborne sound radiated by a certain noise source (such as the machine under test). Note 4: The noise emission descriptor indicated on the product label or product sample may be different. It may refer to the sound power level of the sound source or the sound pressure level at the working position or other specified position.
3.2 Emission sound pressure (p) emission sound pressure refers to the sound pressure at a specified position near the sound source under the specified operating conditions and installation conditions on the reflecting surface. It does not include the background noise and the reflected sound outside one or more reflecting surfaces allowed by the test target. Its unit is Pascal (Pa). .3.3 Emission sound pressure level (L,) emission sound pressure level The logarithm to the base 10 of the ratio of the square of the emission sound pressure p(t) to the square of the reference sound pressure multiplied by 10 is measured using the time weighting and frequency weighting specified in GB3785. The reference sound pressure is 20 μPa. Note 5: For example:
--Maximum A-weighted emission sound pressure level with F time weighting: LpAFmax-C-weighted peak emission sound pressure level: Lpc,peak. The emission sound pressure level should be measured at the specified position, which should comply with the professional test procedures of the machine. If there is no corresponding procedure, it should comply with the provisions of the ISO11200 series of standards. 3.3.1 Time-averaged emission sound pressure level (Lpeqt) Time-averaged emission sound pressure level389
GB/T 17248. 4 ---1998
In a certain measurement time interval T, a noise mean square sound pressure level that varies with time is the same as the continuous steady-state emission sound pressure level in the same time, expressed in decibels (dB), and is expressed by formula (1): dt
LpegT = 10lg[ yuan
A-weighted time-averaged emission sound pressure level is expressed as LpAegT, abbreviated as LpA, and its test instrument should comply with the requirements of IEC804 standard. Note
6 Generally speaking, the subscripts eq and T can be omitted for the result of the time-averaged emission sound pressure level measured in a specified time interval. 7 Formula (1) is the same as the expression of "equivalent continuous sound pressure level" in the GB/T3222 environmental noise standard. However, the definition of this standard refers to the emission of the noise of the machine under test, with specified operating conditions and limited acoustic environment. 3.3.2 Peak emission sound pressure level (Lp, peak) peak emission sound pressure level The instantaneous highest emission sound level measured within an operating cycle. The unit is decibel (dB). 3.3.3 Single-event emission sound pressure level (Lp.1) single-event emission sound pressure level For a single acoustic event, the time-integrated emission sound pressure level within a specified duration T (or specified measurement time T) (usually T. 1s). The unit is decibel and is given by formula (2): 1 p)dt dB
Lpn=10lg.
= Lpear + 10lg .
Note 8: The above formula is the same as the 'exposure level' in environmental noise science, but its emission depends on the characteristics of the sound source and is controlled by the test environment. 3.4 Sound power (W) sound power
The sound energy emitted by the noise source per unit time, in watts (W). 3.5 Sound power level (Lw) sound power level The logarithm of the ratio of the sound power emitted by the noise source under test to the reference sound power multiplied by 10, in decibels (dB). The frequency weighting or bandwidth used should be indicated, and the reference sound power is 1pW (1pW=10=12W). Note 9: The A-weighted sound power level is LwA, and so on. 3.6 Free field over a reflecting plane The noise source is on an infinite and hard plane, and the space above the plane is a homogeneous and isotropic medium. 3.7 Reference body box
The smallest hypothetical rectangular volume along the sound source emission surface that just includes the sound source and ends at the reflecting surface. 3.8 Workstation, operator's position The position designated for the operator near the machine. 3.9 Operator
A person who performs work tasks related to the machine near the machine. 3.10 Specified position (2)
A position designated for a certain machine, but not limited to an operator's position, it can also be other single points, intersection points, or points on a line or a surface at a certain distance from the machine. It can be the test position specified in the machine professional noise test regulations.
Note 10: The position near the workstation or near the unattended machine can be called the "present person position". 3.11 Operational period The time for the tested machine to complete a specified operation (such as the time period from cleaning, rinsing to drying of a dishwasher). 3.12 Operational cycle The time during which the machine under test performs a complex working cycle in a specified sequence; in the entire operation cycle, there may be a period of specified operation time, or it may be repeated multiple times (such as a dishwasher repeatedly washing, rinsing, and drying). 390
4 Measurement uncertainty
GB/T17248.4-1998
The sound pressure level at the working position or specified position obtained by calculating the sound power level is only an approximate value directly measured in an approximately free field above the reflecting surface.
The uncertainty of the two methods for determining the emission sound pressure level in this standard refers to the standard deviation of the repeatability of the emission sound pressure level, which is numerically the same as the uncertainty of the sound power level test method. The uncertainty of determining the sound power level can be found in GB6881, GB6882. GB/T3767, GB/T3768 and GB/T16404 series of standards. 5 Determined quantities
This standard gives methods for calculating the A-weighted sound pressure level LpA and the band sound pressure level from the corresponding sound power level. If you want to know the quantities with time characteristics of the workstation and noise emission (such as the peak C-weighted sound pressure level, LpC,pek, or the single event sound pressure level Lp,1.), you can refer to the international standard ISO 11200. Note 11: Noise emission quantities with time characteristics (such as Lxc.pe;Lp.1) can be determined separately in the actual test environment on site. 6 Methods for determining the emission sound pressure level
6.1 Overview
The two methods described below do not require any special measurements, only that the sound power level of the machine under test has been determined according to the relevant standard methods. The so-called relevant standards refer to the series of standards such as GB/T3767, GB/T3768, GB6881, GB6882 or GB/T16404 or professional standards for machine noise test methods that meet the above standards. 6.2 Methods
6.2.1 General calculation procedure
According to the sound power level Lw of the machine equipment, the sound pressure level LpL, at the specified position can be calculated according to formula (3) = Lw-Q
wherein the value Q can be determined by experiment (Q-Q1, see 6.2.2) or by calculating the test envelope of the machine (Q=Q2, see 6.2.3).
The averaging time, frequency weighting and bandwidth of L in formula (3) are the same as those when testing Lw. 6.2.2 Determine the Q value by experimental method (Q=Q,) This method is only applicable to the noise test method standards of similar machines and equipment that clearly stipulate this aspect and can give the value of Q1. Moreover, batch investigation and testing have been carried out. A Q, value only corresponds to a specified position, at which the emission sound pressure level can be effectively determined. A large number of experimental investigations have shown that the sound power level of the same type of tested machine has a strong correlation with the emission sound pressure level at the specified position. This specified position is actually the working position or other position referred to in Article 1.4. This method is also applicable to small machines with non-directional emission, such as most portable machines. Note 12: For handheld machines, the value of Q1 is generally 4 to 12 dB, depending on the size of the machine. 6.2.3. Determine the Q value by calculation (Q=Q2). The Q2 values of the following situations are calculated by formula (4), among which (a) and (b) are only applicable to the professional test method standards for noise of similar machines, and the standards have clear requirements and specific regulations for the testing of such machines. This method is applicable to:
a) At the working position or other position at a distance d from the reference body of such machine, the noise emission is non-directional; b) The reference body of such machine is placed close to the wall, and the noise energy is reflected by the wall to the working position or specified position at a distance d from the reference body;
c) The operation of such machine requires the operator to move continuously near the distance d from the reference body; d) There is no fixed requirement for the working position, but the average sound pressure level on the test surface at a certain distance (such as 1m) from the reference body is required to be characterized, that is:
GB/T17248.4--1998
Q= 10lg %
（4）
Where: S is the envelope surface area of the working position or other specified position at a given distance d from the noise source reference body, m2. This envelope encloses the sound source;
For detailed provisions on the reference body, please refer to GB3767 and other relevant standards. The value of the general measurement distance d is 0.3~1.0m; the values of Q2S and d are usually specified in the product noise test procedures. The value of S is determined by the specified position, because it mainly depends on the distance d between the specified position and the sound source. This method is mainly applicable to standard machines and equipment of the same type and different sizes. The emission sound pressure level obtained by this method is the average sound pressure level on the S measurement surface under the condition of an approximately free field environment above the reflecting surface.
7 Contents to be recorded
In actual application, the following information should be recorded: 7.1 Sound source
The description of the sound source should include:
a) Model;
b) Technical parameters;bzxz.net
c) Length, width and height;
d) Manufacturer;
e) Machine equipment number;
f) Production date.
7.2 Conditions for determining sound power level
a) National or international standards used or referred to, and indicate their accuracy; b) Operating conditions, exact data on operating time and operating cycle; c) Installation conditions;
d) If necessary, the auxiliary equipment and its installation in the test environment should be described. 7.3 Location of designated position
Precise quantitative description of the working position or designated position where the emission sound pressure level is calculated. 7.4 Method used
The method for determining Q, or Q, and the noise test procedures involved should be recorded. 7.5 Noise data
a) A-weighted emission sound pressure level at the working position or other designated position; b) When actually necessary, the emission sound pressure level of various frequencies or time weightings or frequency bands; c) The date of determination of the sound power level and the name of the person who calculated it. 8 Contents of the report
Only the content required for calculation needs to be recorded in the report (see Chapter 7). If there are professional standards for machine equipment noise testing, the contents of the report should be described in detail in these standards. The report should include:
a) the method used for the first determination of the sound power level and its accuracy; b) the data of the sound power level used in the calculation; 392
c) the original data of the sound power level;
GB/T17248.4—1998
d) which method of this standard is used to calculate the emission sound pressure level; e) the value of Q or Q2;
f) the relevant noise test procedures adopted (if any). Regardless of whether it is consistent with this standard, the emission sound pressure level should be listed in the report. If there is a difference, it should be clearly stated in the report and a reasonable reason should be given. The report should include the measurement date of the sound power level used in the calculation and the name of the person who calculated it. The emission sound pressure level values at the working position or/and other specified positions in the report are approximated to 0.5dB. 393
［1IGB/T14367---93 Acoustics
GB/T17248.4—1998
Appendix A
(Suggestive Appendix)
References
Determination of sound power level of noise source Basic standards for use and criteria for establishing noise test specifications[27 GB/T 16538-1996
［3]GB/T 3222—94
[4] ISO 4871:1996
[57 ISO 7779:1988
[6] ISO 11201:1995
[71 ISO 11202:1995
[8] ISO 11204:1995
Determination of sound power level of noise sources by sound pressure method - Simple method using standard sound source - Methods for measuring environmental noise
Verification and interpretation of noise radiation values of machines and equipment - Measurement of noise radiated by computers and business equipment - Measurement of sound pressure level emitted from workstations and other specified locations - Engineering method for approximation to free field above a reflecting surface - Acoustics - Noise emitted from machines and equipment - Measurement of sound pressure level emitted from workstations and other specified locations - Simple field method
Acoustics - Noise emitted from machines and equipment - Measurement of sound pressure level emitted from workstations and other specified locations - Environmental correction method
[9] ISO 11690-3:1997
7 Acoustics - Guide for design of low-noise workplaces - Part 3: Sound propagation and noise prediction in the workplace4—1998
d) Which method of this standard is used to calculate the emission sound pressure level; e) The value of Q or Q2;
f) The relevant noise test procedures adopted (if any). Regardless of whether it is consistent with this standard, the emission sound pressure level should be listed in the report. If there is a difference, it should be clearly stated in the report and a reasonable reason should be given. The report should include the measurement date of the sound power level used for calculation and the name of the person who calculated it. The emission sound pressure level values at the working position and/or other specified positions in the report are approximated to 0.5dB. 393
［1IGB/T14367---93 Acoustics
GB/T17248.4—1998
Appendix A
(Suggestive Appendix)
References
Determination of sound power level of noise source Basic standards for use and criteria for establishing noise test specifications[27 GB/T 16538-1996
［3]GB/T 3222—94
[4] ISO 4871:1996
[57 ISO 7779:1988
[6] ISO 11201:1995
[71 ISO 11202:1995
[8] ISO 11204:1995
Determination of sound power level of noise sources by sound pressure method - Simple method using standard sound source - Methods for measuring environmental noise
Verification and interpretation of noise radiation values of machines and equipment - Measurement of noise radiated by computers and business equipment - Measurement of sound pressure level emitted from workstations and other specified locations - Engineering method for approximation to free field above a reflecting surface - Acoustics - Noise emitted from machines and equipment - Measurement of sound pressure level emitted from workstations and other specified locations - Simple field method
Acoustics - Noise emitted from machines and equipment - Measurement of sound pressure level emitted from workstations and other specified locations - Environmental correction method
[9] ISO 11690-3:1997
7 Acoustics - Guide for design of low-noise workplaces - Part 3: Sound propagation and noise prediction in the workplace4—1998
d) Which method of this standard is used to calculate the emission sound pressure level; e) The value of Q or Q2;
f) The relevant noise test procedures adopted (if any). Regardless of whether it is consistent with this standard, the emission sound pressure level should be listed in the report. If there is a difference, it should be clearly stated in the report and a reasonable reason should be given. The report should include the measurement date of the sound power level used for calculation and the name of the person who calculated it. The emission sound pressure level values at the working position and/or other specified positions in the report are approximated to 0.5dB. 393
［1IGB/T14367---93 Acoustics
GB/T17248.4—1998
Appendix A
(Suggestive Appendix)
References
Determination of sound power level of noise source Basic standards for use and criteria for establishing noise test specifications[27 GB/T 16538-1996
［3]GB/T 3222—94
[4] ISO 4871:1996
[57 ISO 7779:1988
[6] ISO 11201:1995
[71 ISO 11202:1995
[8] ISO 11204:1995
Determination of sound power level of noise sources by sound pressure method - Simple method using standard sound source - Methods for measuring environmental noise
Verification and interpretation of noise radiation values of machines and equipment - Measurement of noise radiated by computers and business equipment - Measurement of sound pressure level emitted from workstations and other specified locations - Engineering method for approximation to free field above a reflecting surface - Acoustics - Noise emitted from machines and equipment - Measurement of sound pressure level emitted from workstations and other specified locations - Simple field method
Acoustics - Noise emitted from machines and equipment - Measurement of sound pressure level emitted from workstations and other specified locations - Environmental correction method
[9] ISO 11690-3:1997
7 Acoustics - Guide for design of low-noise workplaces - Part 3: Sound propagation and noise prediction in the workplace
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