This standard specifies the measurement method of platform noise and reverberation time of subway stations. This standard is applicable to the measurement of platform noise and reverberation time of subway stations of various forms and structures. GB/T 14228-1993 Measurement of platform noise of subway stations GB/T14228-93 GB/T14228-1993 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Measurement for noise on platform of subway station
1 Subject and scope of application
This standard specifies the measurement method for noise and reverberation time on subway station platforms. GB/T 14228--93
This standard is applicable to the measurement of noise and reverberation time when evaluating subway station platforms of various forms and structures. 2 Reference standards
GB3102.7 Acoustic quantities and units
GB3947 Acoustic terms
GB3241 1/1 and 1/3 octave filters for sound and vibration analysis 3 Quantities measured
3.1 When measuring platform noise, it is the equivalent A sound level of the EMU entering and leaving the station, LAeg, unit: dB. 3.2 When it is necessary to perform spectrum analysis on platform noise, measure the octave band or 1/3 octave band sound pressure level, Lp (Lt), unit: dB. 3.3 Measure the reverberation time T of 500Hz, unit: s. 4 Measuring instruments
4.1 When measuring the frequency band sound pressure level, the filter used should comply with the provisions of GB3241. 4.2 All integrating sound level meters or other measuring instruments and sound level calibrators should be regularly calibrated by the statutory metrology department in accordance with the relevant verification procedures. 4.3 The test system for measuring reverberation time should meet the following requirements: 4.3.1 Sound source system
The loudspeaker as the sound source should be non-directional, and the sound signal is generated by the noise signal generator through a 1/1 or 1/3 octave filter. The filter should comply with the provisions of GB3241. The sound pressure level generated by the sound source in the required frequency band should be at least 35dB higher than the background noise level at the measurement position.
4.3.2 Receiving system
The receiving system includes microphone, measuring amplifier, 1/1 or 1/3 octave filter and recorder. The microphone should be non-directional. The recorder should preferably be a sound level recorder. When recording, the pen speed of the selected recorder should not affect the decay characteristics. And the paper speed of the recorder should be adjusted so that the slope of the decay curve is close to 45°. The recording system can also use a digital recording instrument with the same performance as the sound level recorder that can directly read the reverberation time. 5 Measurement conditions
5.1 Acoustic environment
When measuring, there should be no sound reflectors and sound absorbers within 1.5m around the measuring point. Approved by the State Administration of Technical Supervision on March 6, 1993 174
Implemented on November 1, 1993
5.2 No measurement is performed when vehicles are passing.
5.3 Background noise
GB/T14228—93
When measuring platform noise, the background noise of the platform should be lower than the noise being measured by more than 10 dB. If the difference between the noise being measured and the background noise is within 10 dB, correction shall be made according to Table 1. Table 1 Correction value when the difference between the noise being measured and the background noise is within 10 dBDifference between platform noise level and background noise level
6 Measurement position
Correction value added to the platform noise level
Measurement invalid
6.1 When measuring platform noise, the microphone shall be placed 0.5 m inside the safety line on the vehicle side of the center of the platform and 1.2 m above the ground. The microphone shall point upward with its axis perpendicular to the ground. 6.2 When measuring reverberation time, the measuring point shall be selected at the center of the platform. The distance between the microphone and the ground is 1.5m. The sound source should be placed in the center of the track, 0.5m above the ground, with its axis at about 45° to the ground, and the line connecting the sound source and the measuring point at about 45° to the track direction. Figures 1 and 2 are schematic diagrams of the measuring points of the two platforms.
Location of the sound source and the measuring point when measuring the reverberation time on the side platform
Figure 2 Location of the sound source and the measuring point when measuring the reverberation time on the island platform
7 Measurement method
7.1 Measuring platform noise
GB/T 14228—93
7.1.1 When measuring the equivalent A sound level of the station, the time characteristic of the integrating sound level meter should be set to the "fast" gear. 7.1.2 To measure the A sound level of the train entering and leaving the station, the time and A sound level are measured from the time the head of the EMU enters the station to the time it stops and from the time the EMU starts to the time the tail of the EMU leaves the station. Then the energy average value is calculated according to the following formula, which is the equivalent A sound level of the train entering and leaving the station. La = 10ig(X100 xAT × 100+
Wherein: LAea
-equivalent A-sound level of train entering and leaving the station, dB;
time for a train to enter the station, s;
A-sound level of a train entering the station, dB;
time for a train to leave the station, s,
A-sound level of a train leaving the station, dB.
7.1.3 Continuously measure the equivalent A-sound level of 10 trains entering and leaving the station, and then calculate the arithmetic mean of the 10 equivalent A-sound levels of entering and leaving the station, which represents the average equivalent A-sound level of trains entering and leaving the station at the platform. 7.1.4 The measurement data can be recorded in accordance with Appendix A (reference). 7.2 Measuring platform reverberation time
7.2.1 Measuring the reverberation time when the platform is empty7.2.2 The measurement frequency is 500Hz. For more information The platform reverberation frequency characteristics can measure the reverberation time of 125, 250, 500, 1000, 2000 and 4000Hz.
7.2.3 Number of records and selected values
There should be no less than three effective reverberation time decay curves for the measurement frequency. a.
b. The decay range of the decay curve should not be less than 35dB. The decay curve in this range should be a straight line from 5dB below the starting level to 25dB, and the reverberation time should be determined by the slope of this straight line. When the decay curve is in the shape of a broken line, the front fold should be taken, that is, the linear part from 5dB below the starting level to 15dB, and the reverberation time should be determined from this. According to this provision, the reverberation time taken should be stated in the report. The reverberation time obtained from the effective decay curves of the same frequency The arithmetic mean of the reverberation time is taken as the reverberation time of the frequency. c.
7.2.4 The measurement data can be recorded with reference to Appendix B (reference). 8 Measurement report
The measurement report should include the following contents:
Measurement location;
Measurement date;
Measuring instrument (sound level meter, microphone type, calibration record, sound source equipment, receiving equipment); Measurement location;
Background noise;
Equivalent A sound level of trains entering and leaving the station,
Reverberation time measurement value and average value.
GB/T14228—93
Appendix A
Subway station platform noise measurement record form (reference)
A1 Subway station Platform noise measurements should be recorded according to Table A1. Table A1 Record of noise measurements on subway station platforms Measurement date
Measurement location
Microphone height
Background noise
Tested train number
A sound level
Measurement time
Measurement location
Measurement instrument and microphone model
A sound level
Equivalent A sound level for entering and leaving the station
Presence of sudden sounds such as whistles
Measurement personnel
GB/T14228—93
Appendix B
Record of reverberation time measurements on subway station platforms (reference)
Reverberation time measurements on subway station platforms should be recorded according to Table B1. Table B1 Record of Reverberation Time Measurement of Subway Station Platforms Measurement date
Measurement locationwww.bzxz.net
Microphone height
Model and number of measuring instrument
Background noise
Measurement time
Microphone position
Sound source position
Measurement position and simplified diagram (drawn according to actual measurement). Number of measurements
Additional notes:
Platform form
Frequency, Hz
This standard is proposed by the Ministry of Construction of the People's Republic of China. From
Measurement personnel
This standard is under the jurisdiction of the Ministry of Construction's Urban Construction Standards and Technology Management Unit and the Ministry of Construction's Urban Construction Research Institute. This standard was drafted by the Beijing Institute of Subway Science and Technology, the Ministry of Railways' Institute of Labor Hygiene, and the Changchun Passenger Car Factory of the Ministry of Railways.
The main drafters of this standard are Wang Side, Liu Yang, Zhang Chunhua, Peng Zhanhui, Xu Jianliang, Liu Tujun, Wen Zhiwei, Wang Jinghong and Wang Yuelin. 178
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