Sound insulation indices: A proposal for revision of ISO 717

Juhani Parmanen, Pauli Sysiö

Research output: Book/ReportReport


The report offers a survey on the sound insulation indices that are most widely used in building acoustics. Analyzed are also the procedures of obtaining the indices, especially the ISO 717 reference curve system in comparison with the direct calculation of the sound reduction by the dB(A)-method. On the basis of references, the two methods are seen to be equivalent which means that a reference curve procedure is an algorithm for the respective dB(A)-method yielding an approximation for the acoustical reduction or giving the rating. The report includes a proposal for harmonizing between the methods and, therefore, the ISO 717 reference curve system is suggested to be developed to make it more accurate than before. This will be obtained by revising the sum rule and by taking into account the different characteristics of the incident noise specified in the dB(A)-methods. Proposals for formulating the airborne and impact sound insulation indices are given. The ISO 717 system is suggested to be improved by including a traffic noise index lacking from it before. The reference curve principle will be retained and is meant to be used especially in building codes.
Original languageEnglish
Place of PublicationEspoo
PublisherVTT Technical Research Centre of Finland
Number of pages30
ISBN (Print)951-38-3547-2
Publication statusPublished - 1989
MoE publication typeNot Eligible

Publication series

SeriesValtion teknillinen tutkimuskeskus. Tiedotteita


  • acoustic insulation
  • sound waves
  • noise (sound)
  • methods
  • buildings
  • building codes
  • standards
  • regulations
  • proposals
  • traffic
  • indexes


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