GB/T 39796-2021 English PDF

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GB/T 39796-2021: Test method for airborne sound insulating properties of glass used on multiple units
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Basic data

Standard ID: GB/T 39796-2021 (GB/T39796-2021)
Description (Translated English): Test method for airborne sound insulating properties of glass used on multiple units
Sector / Industry: National Standard (Recommended)
Classification of Chinese Standard: Q34
Word Count Estimation: 14,180
Issuing agency(ies): State Administration for Market Regulation, China National Standardization Administration

GB/T 39796-2021: Test method for airborne sound insulating properties of glass used on multiple units

---This is a DRAFT version for illustration, not a final translation. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.) will be manually/carefully translated upon your order.
Test method for airbone sound insulating properties of glass used on multipe units ICS 81.040.01 Q34 National Standards of People's Republic of China Test method for sound insulation performance of EMU glass Released on 2021-03-09 2021-10-01 implementation State Administration of Market Supervision and Administration Issued by the National Standardization Management Committee Test method for sound insulation performance of EMU glass

1 Scope

This standard specifies the test frequency, test device, test sample and installation, sound insulation measurement, test method for sound insulation performance of EMU glass Sound insulation calculation, test report and other requirements. This standard applies to the sound insulation performance test of EMU glass and doors and windows, as well as other rail transit glass, doors and windows.

2 Normative references

The following documents are indispensable for the application of this document. For dated reference documents, only the dated version applies to this article Pieces. For undated reference documents, the latest version (including all amendments) is applicable to this document. GB/T 3241 Electroacoustic Octave and Fractional Octave Filter GB/T 3785.1-2010 Electroacoustic Sound Level Meter Part 1.Specification GB/T 3947 Acoustic terminology GB/T 15173 Electroacoustic Sound Calibrator GB/T 19889.1 Acoustics Measurement of sound insulation of buildings and building elements Part 1.Laboratory test equipment with suppressed lateral sound transmission Impose requirements GB/T 19889.3-2005 Acoustics Measurement of sound insulation of buildings and building components Part 3.Experiments on airborne sound insulation of building components Room measurement GB/T 20247 Acoustic measurement of sound absorption in a reverberation room GB/T 31004.1-2014 Acoustics Measurement of sound insulation sound intensity of buildings and building components Part 1.Laboratory measurement

3 Terms and definitions

The terms and definitions defined in GB/T 3947, GB/T 19889.3-2005 and GB/T 31004.1-2014 and the following terms and definitions apply to this file. 3.1 Measurementquantity A set of airborne sound insulation data in 1/3 octave band or octave band measured by the instrument. Note. The unit is decibel (dB). 3.2 Referencevalues A set of values used to weigh the measured value when determining the single-value evaluation quantity. Note. The unit is decibel (dB). 3.3 Weighting A method of integrating a set of measured values with a set of benchmark values to obtain a single value. 3.4 Single-numberquantity The single value obtained by weighting the measured value according to the prescribed method. Note. It is expressed as the value at 500Hz, and the unit is decibel (dB). 3.5 Unfavourable deviation The measured value of a certain frequency band is lower than the sum of the reference value of the frequency band and the single-valued evaluation value. Note. The unit is decibel (dB). 3.6 Multipleunitsnoisespectrum The frequency distribution of noise generated during the operation of the EMU. Note. The unit is Hertz (Hz). 3.7 EMU noise A-weighted sound insulation weightedsoundAreductionindexofmultipleunits Rtr,W The single-valued evaluation value within the noise spectrum range of the EMU. Note. It is expressed as the value at 500Hz, and the unit is decibel (dB).

4 Test frequency

The noise spectrum of the EMU adopts 1/3 octave, which should include at least the following center frequencies. 50Hz, 63Hz, 80Hz, 100Hz, 125Hz, 160Hz,.200Hz, 250Hz, 315Hz, 400Hz, 500Hz, 630Hz, 800Hz, 1000Hz, 1250Hz, 1600Hz,.2000Hz, 2500Hz, 3150Hz, 4000Hz, 5000Hz, 6300Hz, 8000Hz, 10000Hz.

5 Test device

5.1 Laboratory The laboratory is shown in Figure 1.The laboratory consists of two adjacent reverberation rooms (sound source room and receiving room), between which is a test hole. The laboratory shall meet the technical requirements specified in GB/T 19889.1. The laboratory layout diagram of the sound pressure method testing device is shown in Figure 1a), and the laboratory layout diagram of the sound intensity method testing device is shown in Figure 1b). Before the equipment is used, a sound calibrator that meets the level 1 accuracy requirements specified in GB/T 15173 should be used to perform the entire measurement system. calibration. The 1/3 octave filter should meet the requirements of GB/T 3241. The reverberation time measurement equipment should meet the requirements of GB/T 20247. The sound source should meet the requirements of 6.1 and Appendix C of GB/T 19889.3-2005. 5.2.2 Sound intensity measurement equipment The sound intensity measurement equipment should comply with the provisions of Chapter 4 in GB/T 31004.1-2014.

6 Test samples and installation

6.1 Test sample For doors and windows, the test sample should be made of products; for glass, the test sample should be made of special products with the same material, structure and process as the product. 6.2 Interstitial Wall When the size of the test sample is smaller than the size of the laboratory test hole, a caulking wall should be constructed in the test hole to suit the installation of the test sample And detection. The interstitial wall should meet the following requirements. a) Heavy materials such as bricks and concrete should be used for construction. It is recommended to use two layers of heavy walls and fill the cavity between the two walls with rock wool (Or glass wool), the joint between the cavity and the test sample hole is sealed with an acoustic reflective elastic material; b) Indirect sound insulation should be inspected and modified according to the method specified in Appendix B of GB/T 19889.3-2005; c) The thickness at the opening of the test sample should not be greater than 500mm. 6.3 Test sample hole The test sample hole should meet the following requirements. a) The width of the hole should be 20mm~30mm larger than the width of the test sample; the height of the hole should be 20mm~ larger than the height of the test sample. 30mm; the bottom of the hole should be about 900mm higher than the ground. When the test sample is a door, the lower threshold should be as close as possible to the test room The floor surface is close to actual usage. b) The sound absorption coefficient of the surface material of the inner wall (top, side and bottom) of the opening should be less than 0.1 in the test frequency range. When the test sample hole When the opening is constructed by bricks or concrete blocks, the inner wall of the opening can be leveled with mortar. 6.4 Test sample installation The installation of test samples shall meet the following requirements. a) The test sample should be embedded in the hole, and the ratio of the depth of the niche on the two side walls should be close to 2.1. b) The gap between the outer frame of the test sample and the opening is uniform. The sample should not be deformed after installation. c) The gap between the outer frame of the test sample and the opening can be sealed according to one of the following methods. 1) Fill the plug with sound-absorbing material (such as rock wool), and seal both sides with putty (covering the sample frame about 10mm). 2) Perform corresponding sealing treatment according to actual requirements. d) If the sealant is used for treatment, the test should be started after the sealant is cured. e) If the test sample is an openable window, before starting the test, all movable fans on the test sample should be normally opened and closed 10 times. Over here During the process, if the seal is damaged or falls off, no remedial measures shall be taken. When testing, the opening and closing on the test sample should be used The device turns off the movable fan. f) When the test sample is glass, it should be fixed with two pieces of wooden bead (25mm×25mm) (see Figure 2). Glass and fixed pressure Use about 5mm thick sealing putty (or the actual required sealing method) to fill in between the strips. The wood bead should cover the glass by no less than Use other methods to make these speakers achieve the uniform non-directional radiation effect specified in C.1.3 of GB/T 19889.3-2005. If multiple sound sources are allowed to be used at the same time, these sound sources should be of the same type, driven at the same level, and emit irrelevant signals. even Sound sources that continue to move can also be used. When a single sound source is used, it must have at least two positions. These speaker locations can be in the same room In the room, or interchange the sound source room and the receiving room in the opposite direction to repeat the measurement, then each room must have one or more sound source locations for measurement measuring. If the sound absorption of one side of the test sample is significantly greater than the other side, the side with higher sound absorption should face the sound source room. The loudspeaker should be placed as far as possible to provide a diffuse sound field, and a certain distance from the test sample to make the direct sound as small as possible. room The internal sound field is greatly affected by the type and location of the sound source. The technical requirements of the loudspeaker and the placement of the points shall be in accordance with the appendix of GB/T 19889.3-2005 C's requirements are implemented. Refer to C.2.5 of GB/T 19889.3-2005 for instructions on using mobile speakers. 7.2.2 Measurement of average sound pressure level 7.2.2.1 General The average sound pressure level can be obtained by the following methods. using a continuous moving single microphone or using a rotating microphone; using a single transmitter The microphones are measured at different positions or a fixed array of microphones is used. For all sound source positions, the sound pressure levels measured at different measuring points should be Average according to energy algorithm. If a continuously moving microphone is used for measurement, the indoor average sound pressure level L is calculated according to formula (1). L=10lg Tm∫ Tm p2(t)dt p20 (1) Where. p ---sound pressure, the unit is Pa (Pa); p0 ---reference sound pressure, the value is 20μPa; Tm ---Integration time, in seconds (s). If several fixed-position microphones are used for measurement, the indoor average sound pressure level L is calculated according to formula (2). L=10lg p21 p22 p2n n×p20 (2) Where. p1,p2,..,pn---the root mean square value of the sound pressure measured at n different positions in the room. In actual work, several sound pressure levels Li are usually measured. At this time, the average indoor sound pressure level L is calculated according to formula (3). L=10lg n∑ i=1 10Li/10 (3) Where. Li---The sound pressure level of n different measuring points in the room, from L1 to Ln. 7.2.2.2 Microphone position The position of the microphone shall comply with the provisions of 6.2.2 of GB/T 19889.3-2005. 7.2.2.3 Average time At each microphone measuring point, the frequency band whose center frequency is lower than 400Hz, the average time is at least 6s. For higher center frequencies For some frequency bands, the average time can be slightly shorter, but it should not be less than 4s. If a mobile microphone is used, the average time should be It is the sum of all scanning points and should not be less than 30s. 7.2.3 Frequency range of measurement When the sound pressure level is measured with a 1/3 octave filter, it should include at least the frequencies in Chapter 4. 7.2.4 Reverberation time measurement and sound absorption estimation The measurement of reverberation time is carried out in accordance with the method specified in GB/T 20247. The sound absorption is calculated according to formula (4). A= 0.16V (4) Where. A ---Sound absorption, in square meters (m2); V --- the volume of the receiving room, in cubic meters (m3); T --- Reverberation time in the receiving room, in seconds (s). 7.2.5 Correction of background noise The background noise level of any frequency band in the receiving room should be at least 6dB lower than the total sound pressure level of the signal sound pressure level and the background noise superimposed, and it should be low. Above 15dB. If the difference is between 6dB and 15dB, the signal sound pressure level of the receiving room should be corrected according to formula (5). L=10lg(10Lab/10-10Lb/10) (5) Where. L ---corrected signal sound pressure level, in decibels (dB); Lab --- the total sound pressure level after the signal and background noise are superimposed, in decibels (dB); Lb --- background noise sound pressure level, in decibels (dB). If the difference in sound pressure level in any frequency band is less than or equal to 6dB, the correction value 1.3dB when the difference is 6dB is used for correction. In this case, the sound insulation (R) given in the measurement report must clearly indicate that the R value is the limit of the measurement. 7.2.6 Expression of sound insulation results by sound pressure method The sound insulation R of the test sample in each 1/3 octave band is calculated according to formula (6). R=L1-L2 10lg (6) Where. R ---Sound insulation, in decibels (dB); L1 --- The average sound pressure level in the sound source room, in decibels (dB); L2 --- The average sound pressure level in the receiving room, in decibels (dB); S ---The area of the sample hole, in square meters (m2); A ---The amount of sound absorption in the receiving room, in square meters (m2). In order to illustrate the air sound insulation performance of the test sample, the sound insulation capacity of all frequencies (with one decimal place) should be given in the form of tables and curves. Out. The ordinate in the graph is the sound insulation R, in dB; the abscissa is the frequency in logarithmic coordinates, in Hz, and the following scale is used. ---5mm represents a 1/3 octave band; ---20mm means 10dB. If the test procedure is repeated in the same or opposite measurement directions, the arithmetic average of all measurement results for each frequency band can be taken. 7.3 Sound insulation measurement by sound intensity method 7.3.1 Sound insulation measurement The sound intensity and sound insulation RI are measured according to the method specified in 6.4 of GB/T 31004.1-2014, and the measurement frequency range should at least include Contains the center frequency in Chapter 4. 8.2 EMU noise A weighting curve comparison method The curve comparison method is carried out as follows. a) Draw a set of measurement values of air sound insulation in the 1/3 octave band with an accuracy of 0.1dB as a spectrum of measured values on graph paper curve; b) Cover the transparent paper with the same coordinate ratio and drawn the reference curve of 1/3 octave air sound insulation on the seat with the above-mentioned curve. On the mark paper, make the abscissas overlap each other, and align the reference curve 0dB in the ordinate with an integer coordinate of the spectrum curve; c) Move the reference curve to the spectrum curve of the measured value, 1dB per step, until the sum of the unfavorable deviations is as large as possible, but not more than 32.0dB; d) At this time, the integer decibel of the vertical coordinate of the graph paper with the measured value spectrum curve corresponding to the abscissa 500Hz on the reference curve is The weighted sound insulation corresponding to the set of measured values.

9 Test report

The test report should include at least the following. a) The name and address of the entrusting unit; b) The name of the sample manufacturer, variety, model, specification and related icons; c) The sample installation situation, the sealing treatment around the sample and the description of the sample hole; d) Standard number and equipment; e) The temperature and relative humidity of the receiving room, the volume of the sound source room and the receiving room; f) Use a table to give the relationship between the sound insulation, correction and frequency of the sample; g) The A-weighted sound insulation Rtr, W of the sample's EMU noise, indicating which test method is used; h) The name and address of the inspection unit, the number of the inspection report, the date of the inspection, the signature of the chief inspector and the reviewer, and the seal of the inspection unit. ......

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