1.0.1 This code is formulated with a view to reducing noise influence to civil buildings and ensuring favorable sound environment in civil buildings.
1.0.2 This code is applicable to the sound insulation, sound absorption and noise reduction design for main houses in 6 categories of constructed, renovated and extended buildings such as dwelling, school, hospital, hotel, office-building and commercial building in towns and cities all over the country. As for rooms in other categories of buildings, corresponding provisions of this code can be adopted according to their functions.
1.0.3 A-weighted sound pressure level shall be adopted as the rating quantity of limits for indoor noise levels in this code. The limits for indoor noise levels in this code shall be the standard values under the closed window condition at daytime and nighttime. As for the rooms with open windows in hospital, the standard values of limits for indoor noise levels under the open window condition should be the same as those under the closed window condition. Corresponding time of daytime and nighttime respectively is: daytime, 6:00~22:00; nighttime, 22:00~6:00; or as the requirements of local People's Government. The measurement of indoor noise level shall be carried out according to those specified in Appendix A of this code.
1.0.4 As for the design of sound insulation and noise reduction of civil buildings, not only the requirements stipulated in this code, but also those in the current relevant standards of the nation shall be complied with.
2 Terminologies and Symbols
2.1 Terminologies
2.1.1 A-weighted sound pressure level
Sound pressure level measured by A-weighted network.
2.1.2 Equivalent [continuous A-weighted] sound pressure level
Within the stipulated time limit, A [-weighted] sound pressure of a certain continuous steady-state sound has the same mean square A [-weighted] sound pressure as the time-varying noise, so the sound level of this continuous steady-state sound is the equivalent sound level of this time-varying noise, and the unit is decibel (dB).
2.1.3 Air-borne sound
The sound featured by sound source spreading toward surrounding areas through air.
2.1.4 Impact sound
Noise caused by impacting on building structures.
2.1.5 Single-number quantity
Single sound insulation parameter determined in comprehensive consideration of the sound insulation performance of objects at 1/3 octave within the range of 100Hz~3,150Hz center frequency (or 1/1 octave within the range of 135Hz~2,000Hz center frequency), according to the methods specified in the national standard "Rating Standard of Sound Insulation in Buildings" (GB/T 50121-2005).
2.1.6 Weighted sound reduction index
Single-number quantity representing the air-borne sound insulation performance of building members. Weighted sound reduction index should be measured in the laboratory.
2.1.7 Weighted standardized level difference
Single-number quantity of air-borne sound insulation performance between two rooms obtained by using the reverberation time of reception room as the correction parameter.
2.1.8 Weighted normalized impact sound pressure level
Single-number quantity of impact sound insulation performance of floorslabs or floorslab structures obtained by using the sound absorption index of reception room as the correction parameter.
2.11.9 Weighted standardized impact sound pressure level
Single-number quantity of impact sound insulation performance of floorslabs or floorslab structures obtained by using the reverberation time of reception room as the correction parameter.
2.1.10 Spectrum adaptation term
Spectrum adaptation term is the corrected value added to the single-number quantity of air-borne sound insulation due to different sound insulation spectrums and different noise spectrums in sound source space. When the noise in sound source space is in the pink noise frequency characteristics or traffic noise frequency characteristics, the calculated spectrum adaptation term is pink noise spectrum adaptation term or traffic noise spectrum adaptation term respectively.
2.1.11 Noise reduction coefficient
Single value of material sound absorption characteristics obtained by calculating the measured values of random incident absorption coefficient at 1/3 octave within the range of 200Hz~2,500Hz center frequency.
2.2 Symbols
C - pink noise spectrum adaptation term;
Ctr - traffic noise spectrum adaptation term;
DnT,w - weighted standardized level difference;
LAeq,T - equivalent [continuous A-weighted] sound pressure level;
Ln,w - weighted normalized impact sound pressure level;
L′nT,w - weighted standardized impact sound pressure level;
NRC - noise reduction coefficient;
Rw - weighted sound reduction index.