1.1 General
This part of ISO15186 specifies a sound intensity method to determine the in-situ sound insulation of walls, floors, doors, windows and small building elements. It is intended for measurements that have to be made in the presence of flanking transmission. It can be used to provide sound power data for diagnostic analysis of flanking transmission or to measure flanking sound insulation parameters.
This part of ISO15186 can be used by laboratories that could not satisfy the requirements of ISO15186-1, which deals with laboratory measurements with no or little flanking transmission. ISO15186-3 deals with measurements under laboratory conditions, at low frequencies.
This part of ISO15186 also describes the effect of flanking transmission on measurements made using the specified method, and how intensity measurements can be used
to compare the in-situ sound insulation of a building element with laboratory measurements where flanking has been suppressed (i.e. ISO140-3),
to rank the partial contributions for building elements, and
to measure the flanking sound reduction index for one or more transmission paths (for validation of prediction models such as those given in EN12354-1).
This method gives values for airborne sound insulation, which are frequency dependent. They can be converted into a single number, characterizing the acoustic performance, by application of ISO717-1.
1.2 Precision
The reproducibility of this intensity method is estimated to be equal to or better than that of the methods of ISO140-10 and ISO140-4, when measuring a single small and large building element, respectively.
NOTE1 If sound reduction measures made using this method are to be compared with those made using the conventional reverberation room method in various parts of ISO140, then it will be necessary to introduce an adaptation term that reflects the bias between the test methods. This term is given in Annex A.
NOTE2 Some information about the accuracy for this part of ISO15186 and its relationship to the sound reduction index measured according to ISO140-3 and ISO140-4 is given in Annex B.
NOTE3 Flanking transmission is discussed in Annex C.