Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard replaces GB/T 22036-2008 Coast-by methods for measurement of tyre-to-road sound emission, and the following main technical changes have been made with respect to GB/T 22036-2008:
—— Sub-clause 3.1 in 2008 Edition is deleted;
—— Sub-clause 3.2 in 2008 Edition is deleted;
—— The requirement “Windscreens shall be used when the wind speed reaches 2 m/s or more” is added (see Sub-clause 6.1);
—— The test range that requires at least 20m is added (see Sub-clause 6.2);
—— "Sound Pressure Level A" is changed to "sound pressure level corresponding to the frequency of each one-third frequency band center" (see Sub-clause 7.2);
—— Test surface verification is added (see Clause 9);
—— The content “Deviation of left and right tyre loads shall be less than 10%” is added. [See Sub-clause A.1.4 c)];
—— The test report and examples of test records are deleted (see Sub-clauses A.3 and B.5 in 2008 Edition).
This standard has been redrafted and modified adoption of International Standard ISO 13325:2003 Tyres - Coast-by methods for measurement of tyre-to-road sound emission (English version).
Technical deviations between this standard and the International Standard ISO 13325:2003 and their justifications are as follows:
—— The adjustments of technical difference are made for the normative references in this standard so as to adapt to the technical conditions in China. The adjustment conditions are mainly reflected in Clause 2 "Normative references"; the specific adjustments are as follows:
GB/T 3785.1-2010 identical to the international standard is used to replace ISO 60651:2001 sound-level meter; see Sub-clause 6.1);
GB/T 6326 non-equivalent to the international standard is used to replace ISO 4223-1 (see Clause 3);
GB/T 15173-2010 identical to the international standard is used to replace IEC 60942:1997 (see Sub-clause 6.1);
Referenced document ISO 362.1:2015 is added (see Clause 5).
—— Sub-clause 3.1 is deleted and directly described by definition in the text;
—— Sub-clause 3.2 is deleted as the term is already in GB/T 6326.
—— The requirement “Windscreens shall be used when the wind speed reaches 2m/s or more” is added (see Sub-clause 6.1) to minimize the influence on the test results;
—— The test range that requires at least 20m (see Sub-clause 6.2) is added to avoid influence on test results;
—— "Sound Pressure Level A" is changed to "sound pressure level corresponding to the frequency of each one-third frequency band center" (see Sub-clause 7.2) as such expression is more accurate;
—— Test surface verification is added (see Clause 9) to ensure more accurate test conditions;
—— “Deviation of left and right tyre loads” shall be less than 10%” is added to ensure more accurate test results. [See A.1.4 c)];
—— The test report and examples of test records are deleted (see Sub-clauses A.3 and B.5 in 2008 Edition). It is quite feasible to design test report and test record table according to the contents of requirements.
The following editorial changes have been made in this standard:
—— the standard name is modified;
—— the bibliography is deleted.
This standard was proposed by China Petroleum and Chemical Industry Association.
This standard is under the jurisdiction of the National Technical Committee on Tyres and Rims of Standardization Administration of China (SAC/TC 19).
The previous edition replaced by this standard is as follows:
—— GB/T 22036-2008.
Coast-by methods for measurement of tyre-to-road sound emission
1 Scope
This standard specifies methods for measuring tyre-to-road sound emissions from tyres fitted on a motor vehicle or towed trailer under coast-by conditions, i.e. when the vehicle or trailer is in free-rolling, non-powered operation, with transmission in the neutral position and the engine as well as all auxiliary systems not necessary for safe driving switched off. Whereas the results of the vehicle method are closer to the tyres sound than those of hat the trailer method, the tyre sound is affected by suspension; the test results of trailer method can be even closer to sound emissions produced by the tyres alone.
This standard is applicable to new tyres of passenger cars and trucks. It is neither applicable to determine the sound contribution (sound field distribution) of tyres of vehicles running in normal condition nor to the determination of traffic sound and its damage degree at a given location.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 362.1 Measurement of noise emitted by accelerating road vehicles - Engineering method - Part 1: M and N categories
ISO 10844 Acoustics - Specification of test tracks for measuring noise emitted by road vehicles and their tyres
3 Terms and definitions
For the purposes of this document, the terms and definitions defined in GB/T 6326 apply.
4 General
This standard is applicable to measurement of sound emitted from the tyre of a test motor vehicle (see Annex A) or trailer (see Annex B) in coast-by conditions.
The test results are an objective measure of the sound emitted under the prescribed conditions of the test, i.e. A-weighted sound pressure level.
5 Test site
The test site shall be a semi-free acoustical field consisting of a substantially flat and level area. Conditions of the acoustical field are: a non-directional sound source is placed in the center of the site, and the sound pressure deviation in all directions on the hemisphere surface shall not exceed ±1dB. These conditions shall be deemed to be met if there is no large sound reflecting object, such as fences, rocks, bridges or buildings, within 50m of the center of the test area.
The test surface, including voids, shall be dry and clean for all measurements. The test area and surface shall meet the requirements of ISO 10844. The measurement zone and the microphone location are shown in Figure 1.
Keys:
● —— the microphone location (1.2 m high);
CC′ —— the centerline of travel;
ls —— the length of acceleration zone;
la ——the length of steady speed driving zone (test extension zone);
Light gray zone: extension zone;
Deep gray zone with dotted line: test track.
Figure 1 Plan dimensions of test site
In Figure 1, on the outer sides of A-A and B-B are stable speed driving tracks with the length of la and the width of at least 3 m. The selection of la value is shown in Table 1. It is recommended that the length of acceleration zone ls of the test be at least 60 m.
Table 1 Minimum extension length of driving tracks
Length Rear engines with a distance of more than 10 m between the reference point and the front axle
Extended vehicles (reference point is defined in ISO 362-1) Other vehicles
la 20 ma 10 m
a The distance between both ends of the two-way driving test site is 20 m; the approach section of one-way driving test site can also be 10 m, and the exit section is 20 m.
6 Instrumentation
6.1 Instrumentation for acoustical measurements
The sound pressure level meter or equivalent measuring system (including anti-wind ball) shall at least meet the requirements of Type 1 instrument in accordance with GB/T 15173-2010.
The measurements shall be made using the “A” frequency-weighted characteristic, and “F” time-weighted characteristic.
The calibration of the sound pressure level meter shall be checked and adjusted in accordance with the manufacturer’s instructions or with a standard sound source (e.g. pistonphone) at the beginning of the measurements and rechecked and recorded at the end of them. The calibration device shall meet the requirements of Class 1 in accordance with GB/T 15173-2010.
If the sound pressure level meter indications obtained from these calibrations differs by more than 0.5dB during a series of measurements, the test shall be considered invalid. Any deviation shall be recorded in the test report.
At intervals of not more than one year, the sound pressure level meter and the calibration device shall be verified with the requirements of GB/T 3785.1-2010 and GB/T 15173-2010.
Windscreens shall be used when the wind speed reaches 2 m/s or more.
The test area and surface shall be in accordance with ISO 10844, as shown in Figure 1. Additionally, there shall be no large acoustically reflective objects within the radius shown in Figure 1.
6.2 Microphones
Two microphones shall be used in the test, one on each side of the vehicle/trailer. In the vicinity of the microphones, there shall be no obstacle that could influence the acoustical field and no person shall remain between the microphones and the sound source. Any observer or observers shall be positioned at least 20 m away from the microphone so as not to influence the measurement result of the instrument.
The distance from the microphone positions to the centerline of travel on the test track shall be (7.5 ± 0.05) m. Each microphone shall be located (1.2 ± 0.02) m above the test area surface. The reference axis shall be horizontal and vertically directing to the centerline of travel.
6.3 Temperature measurement
6.3.1 General
For air as well as test surface temperature, the measuring instrument shall have an overall accuracy within ±1℃. Meters utilizing the infrared technique shall not be used for air temperature measurements.
The type of sensor shall be reported.
Continuous record of temperature via instruments may be employed. If such an option is not available, single values are to be measured and recorded.
Measurements of air as well as test surface temperatures are mandatory. The final results are the readings rounded to the nearest integer in degrees Celsius.
Temperature measurements shall correspond reasonably over time with sound measurements of tyres in both vehicle and trailer methods. Alternatively, the average of the temperature at the beginning and the end of the set of tests may be used in both methods.
6.3.2 Air temperature
Position the temperature sensor in an unobstructed and sheltered location close to the microphone, such that it is exposed to the airflow and protected from direct solar radiation. The latter may be achieved by any shading screen or similar device. The sensor shall be positioned 1.2 m±0.1m above the test surface level, to minimize the influence of low airflows caused by test surface thermal radiation.
6.3.3 Test surface temperature
Position the temperature sensor in a location where the temperature is representative of the temperature in the wheel tracks, without interfering with the sound measurement.
If an instrument with a contact temperature sensor is used, apply heat-conductive paste between the surface and the sensor to ensure adequate thermal contact.
If a radiation thermometer is used, the height shall be chosen to ensure that a measuring spot with a diameter of ≥0.1 m is covered.
The test surface shall not be artificially cooled during or prior to testing.
Foreword i 1 Scope 2 Normative references 3 Terms and definitions 4 General 5 Test site 6 Instrumentation 7 Meteorological conditions and background sound 8 Preparation and adjustments with respect to tyres 9 Test surface verification Annex A (Normative) Vehicle method Annex B (Normative) Trailer method
Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard replaces GB/T 22036-2008 Coast-by methods for measurement of tyre-to-road sound emission, and the following main technical changes have been made with respect to GB/T 22036-2008:
—— Sub-clause 3.1 in 2008 Edition is deleted;
—— Sub-clause 3.2 in 2008 Edition is deleted;
—— The requirement “Windscreens shall be used when the wind speed reaches 2 m/s or more” is added (see Sub-clause 6.1);
—— The test range that requires at least 20m is added (see Sub-clause 6.2);
—— "Sound Pressure Level A" is changed to "sound pressure level corresponding to the frequency of each one-third frequency band center" (see Sub-clause 7.2);
—— Test surface verification is added (see Clause 9);
—— The content “Deviation of left and right tyre loads shall be less than 10%” is added. [See Sub-clause A.1.4 c)];
—— The test report and examples of test records are deleted (see Sub-clauses A.3 and B.5 in 2008 Edition).
This standard has been redrafted and modified adoption of International Standard ISO 13325:2003 Tyres - Coast-by methods for measurement of tyre-to-road sound emission (English version).
Technical deviations between this standard and the International Standard ISO 13325:2003 and their justifications are as follows:
—— The adjustments of technical difference are made for the normative references in this standard so as to adapt to the technical conditions in China. The adjustment conditions are mainly reflected in Clause 2 "Normative references"; the specific adjustments are as follows:
GB/T 3785.1-2010 identical to the international standard is used to replace ISO 60651:2001 sound-level meter; see Sub-clause 6.1);
GB/T 6326 non-equivalent to the international standard is used to replace ISO 4223-1 (see Clause 3);
GB/T 15173-2010 identical to the international standard is used to replace IEC 60942:1997 (see Sub-clause 6.1);
Referenced document ISO 362.1:2015 is added (see Clause 5).
—— Sub-clause 3.1 is deleted and directly described by definition in the text;
—— Sub-clause 3.2 is deleted as the term is already in GB/T 6326.
—— The requirement “Windscreens shall be used when the wind speed reaches 2m/s or more” is added (see Sub-clause 6.1) to minimize the influence on the test results;
—— The test range that requires at least 20m (see Sub-clause 6.2) is added to avoid influence on test results;
—— "Sound Pressure Level A" is changed to "sound pressure level corresponding to the frequency of each one-third frequency band center" (see Sub-clause 7.2) as such expression is more accurate;
—— Test surface verification is added (see Clause 9) to ensure more accurate test conditions;
—— “Deviation of left and right tyre loads” shall be less than 10%” is added to ensure more accurate test results. [See A.1.4 c)];
—— The test report and examples of test records are deleted (see Sub-clauses A.3 and B.5 in 2008 Edition). It is quite feasible to design test report and test record table according to the contents of requirements.
The following editorial changes have been made in this standard:
—— the standard name is modified;
—— the bibliography is deleted.
This standard was proposed by China Petroleum and Chemical Industry Association.
This standard is under the jurisdiction of the National Technical Committee on Tyres and Rims of Standardization Administration of China (SAC/TC 19).
The previous edition replaced by this standard is as follows:
—— GB/T 22036-2008.
Coast-by methods for measurement of tyre-to-road sound emission
1 Scope
This standard specifies methods for measuring tyre-to-road sound emissions from tyres fitted on a motor vehicle or towed trailer under coast-by conditions, i.e. when the vehicle or trailer is in free-rolling, non-powered operation, with transmission in the neutral position and the engine as well as all auxiliary systems not necessary for safe driving switched off. Whereas the results of the vehicle method are closer to the tyres sound than those of hat the trailer method, the tyre sound is affected by suspension; the test results of trailer method can be even closer to sound emissions produced by the tyres alone.
This standard is applicable to new tyres of passenger cars and trucks. It is neither applicable to determine the sound contribution (sound field distribution) of tyres of vehicles running in normal condition nor to the determination of traffic sound and its damage degree at a given location.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 3785.1-2010 Electroacoustics - Sound level meters - Part 1 Specification (IEC 61672-1:2002, IDT)
GB/T 6326 Tyre terms and definitions (GB/T 6326-2014, ISO 4223-1:2002, Definitions of some terms used in tyre industry - Part 1: Pneumatic tyres, NEQ)
GB/T 15173-2010 Electroacoustics - Sound calibrators (IEC 60942:2003, IDT)
ISO 362.1 Measurement of noise emitted by accelerating road vehicles - Engineering method - Part 1: M and N categories
ISO 10844 Acoustics - Specification of test tracks for measuring noise emitted by road vehicles and their tyres
3 Terms and definitions
For the purposes of this document, the terms and definitions defined in GB/T 6326 apply.
4 General
This standard is applicable to measurement of sound emitted from the tyre of a test motor vehicle (see Annex A) or trailer (see Annex B) in coast-by conditions.
The test results are an objective measure of the sound emitted under the prescribed conditions of the test, i.e. A-weighted sound pressure level.
5 Test site
The test site shall be a semi-free acoustical field consisting of a substantially flat and level area. Conditions of the acoustical field are: a non-directional sound source is placed in the center of the site, and the sound pressure deviation in all directions on the hemisphere surface shall not exceed ±1dB. These conditions shall be deemed to be met if there is no large sound reflecting object, such as fences, rocks, bridges or buildings, within 50m of the center of the test area.
The test surface, including voids, shall be dry and clean for all measurements. The test area and surface shall meet the requirements of ISO 10844. The measurement zone and the microphone location are shown in Figure 1.
Keys:
● —— the microphone location (1.2 m high);
CC′ —— the centerline of travel;
ls —— the length of acceleration zone;
la ——the length of steady speed driving zone (test extension zone);
Light gray zone: extension zone;
Deep gray zone with dotted line: test track.
Figure 1 Plan dimensions of test site
In Figure 1, on the outer sides of A-A and B-B are stable speed driving tracks with the length of la and the width of at least 3 m. The selection of la value is shown in Table 1. It is recommended that the length of acceleration zone ls of the test be at least 60 m.
Table 1 Minimum extension length of driving tracks
Length Rear engines with a distance of more than 10 m between the reference point and the front axle
Extended vehicles (reference point is defined in ISO 362-1) Other vehicles
la 20 ma 10 m
a The distance between both ends of the two-way driving test site is 20 m; the approach section of one-way driving test site can also be 10 m, and the exit section is 20 m.
6 Instrumentation
6.1 Instrumentation for acoustical measurements
The sound pressure level meter or equivalent measuring system (including anti-wind ball) shall at least meet the requirements of Type 1 instrument in accordance with GB/T 15173-2010.
The measurements shall be made using the “A” frequency-weighted characteristic, and “F” time-weighted characteristic.
The calibration of the sound pressure level meter shall be checked and adjusted in accordance with the manufacturer’s instructions or with a standard sound source (e.g. pistonphone) at the beginning of the measurements and rechecked and recorded at the end of them. The calibration device shall meet the requirements of Class 1 in accordance with GB/T 15173-2010.
If the sound pressure level meter indications obtained from these calibrations differs by more than 0.5dB during a series of measurements, the test shall be considered invalid. Any deviation shall be recorded in the test report.
At intervals of not more than one year, the sound pressure level meter and the calibration device shall be verified with the requirements of GB/T 3785.1-2010 and GB/T 15173-2010.
Windscreens shall be used when the wind speed reaches 2 m/s or more.
The test area and surface shall be in accordance with ISO 10844, as shown in Figure 1. Additionally, there shall be no large acoustically reflective objects within the radius shown in Figure 1.
6.2 Microphones
Two microphones shall be used in the test, one on each side of the vehicle/trailer. In the vicinity of the microphones, there shall be no obstacle that could influence the acoustical field and no person shall remain between the microphones and the sound source. Any observer or observers shall be positioned at least 20 m away from the microphone so as not to influence the measurement result of the instrument.
The distance from the microphone positions to the centerline of travel on the test track shall be (7.5 ± 0.05) m. Each microphone shall be located (1.2 ± 0.02) m above the test area surface. The reference axis shall be horizontal and vertically directing to the centerline of travel.
6.3 Temperature measurement
6.3.1 General
For air as well as test surface temperature, the measuring instrument shall have an overall accuracy within ±1℃. Meters utilizing the infrared technique shall not be used for air temperature measurements.
The type of sensor shall be reported.
Continuous record of temperature via instruments may be employed. If such an option is not available, single values are to be measured and recorded.
Measurements of air as well as test surface temperatures are mandatory. The final results are the readings rounded to the nearest integer in degrees Celsius.
Temperature measurements shall correspond reasonably over time with sound measurements of tyres in both vehicle and trailer methods. Alternatively, the average of the temperature at the beginning and the end of the set of tests may be used in both methods.
6.3.2 Air temperature
Position the temperature sensor in an unobstructed and sheltered location close to the microphone, such that it is exposed to the airflow and protected from direct solar radiation. The latter may be achieved by any shading screen or similar device. The sensor shall be positioned 1.2 m±0.1m above the test surface level, to minimize the influence of low airflows caused by test surface thermal radiation.
6.3.3 Test surface temperature
Position the temperature sensor in a location where the temperature is representative of the temperature in the wheel tracks, without interfering with the sound measurement.
If an instrument with a contact temperature sensor is used, apply heat-conductive paste between the surface and the sensor to ensure adequate thermal contact.
If a radiation thermometer is used, the height shall be chosen to ensure that a measuring spot with a diameter of ≥0.1 m is covered.
The test surface shall not be artificially cooled during or prior to testing.
Contents of GB/T 22036-2017
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 General
5 Test site
6 Instrumentation
7 Meteorological conditions and background sound
8 Preparation and adjustments with respect to tyres
9 Test surface verification
Annex A (Normative) Vehicle method
Annex B (Normative) Trailer method
