绿色建筑评价中楼板撞击声隔声指标探讨

Discussion on Evaluation Indexes of Floor Impacting on Sound Insulation in Green Buildings

绿色建筑评价中对楼板撞击声隔声的要求引用《民用建筑隔声设计规范》,单值评价量有实验室测量的计权规范化撞击声压级L_(n,w)和现场测量的计权标准化撞击声压级L'_(n T,w)。对撞击声隔声评价指标L_(n,w)、L'_(n,w)、L'_(n T,w)进行理论分析,并结合现场测量和实验室测量对分析结果进行验证。结果表明:当建筑楼板的撞击声隔声性能较差时,侧向传声对测量结果影响较小,现场测量指标L'_(n,w)与实验室测量指标L_(n,w)相差不大;L'_(n T)与L'_n在接收室体积V=31m^(3)时相等,当接收室体积V>31m^(3)时,L'_(n T)会小于L'_n,因此L'_(n T,w)会低于L'_(n,w)和实验室测量值L_(n,w),接收室体积越大偏差越大,按照当前住宅户型的发展趋势,客厅体积一般在60~130m^(3),采用L'_(n T,w)进行撞击声隔声评价会导致其数值低于实验室测量指标L_(n,w),约为3~6d B;采用现场测量指标L'_(n T,w)进行撞击声隔声评价会受到接收房间体积的影响,因此建议在现场绿色建筑楼板撞击声隔声性能评价时同时参考L'_(n,w)的测量结果。

The requirements for floor impact sound insulation in green building evaluations refer to Code for Design of Sound Insulation For Civil Buildings.The single-number quantities include weighted normalised impact sound pressure level Ln,w as laboratory measurements,and weighted standardised impacts on sound pressure level L'_(nT,w) for field measurements.According to the code,Ln,w can be used by designers for material selection in sound insulation design and L'_(nT,w) is the actual value to be achieved following completion of ground decoration.The correction term of normalised impact sound pressure level L'n for field measurement corresponding to L'_(n,w) is calculated by the same method of Ln for laboratory measurement corresponding to Ln,w.L'n and Ln are corrected according to the ratio of the measured equivalent absorption areas of the receiving room to the reference equivalent absorption area of 10m^(3).However,the correction term of standardised impact sound pressure level L'_(nT) corresponding to L'_(nT,w) is calculated differently from that of L'n and Ln.The correction is according to the ratio of the measured reverberation time in the receiving room to the reference reverberation time of 0.5s.Due to varying calculation methods,there will be a deviation between laboratory and field measurements of the same floor structure.The two single-number quantities are listed in the code simultaneously,which contributes to confusion for the green building evaluators.The impact sound insulation evaluation indexes Ln,w,L'_(n,w),L'_(nT,w),are theoretically analysed in the current study.Results are verified using field and laboratory measurements.The results show that the lateral sound transmission has little influence on the measurement results for poor impact sound insulation performances of the building floor.The field measurement index L'_(n,w) is not different from the laboratory measurement index Ln,w.Moreover,L'_(nT) is equal to L'n only when the volume of the receiving chamber is V=31m^(3).When the volume of receiving chamber V>31m^(3),L'_(nT) will be less than L'n,so L'_(nT,w) will be lower than L'_(n,w) accordingly.The larger the volume of the receiving chamber,the greater the deviation.According to the current developmental trends of residential buildings,the living room volume is generally 60~130m^(3).The impact sound insulation evaluation based on L'_(nT,w) is generally approximately 3~6dB lower than the Ln,w.The impact sound insulation evaluation based on L'_(nT,w) is sensitive to the volume of the receiving room.Therefore,it is recommended that the impact sound insulation of green buildings should be evaluated based on the field data of L'_(n,w).