<p>ISO 15186-3:2002 specifies a sound intensity method to determine the sound reduction index and the element-normalized level difference of building elements at low frequencies. This method has significantly better reproducibility in a typical test facility than those of ISO 140-3, ISO 140-10 and ISO 15186-1. The results are more independent of the room dimensions of the laboratory and closer to values that would be measured between rooms of volume greater than 300 m<sup>3</sup>. ISO 15186-3 is applicable in the frequency range 50 Hz to 160 Hz but is mainly intended for the frequency range 50 Hz to 80 Hz.</p>
<p>NOTE For elements faced with thick, porous absorbers, the recommended frequency range is 50 Hz to 80 Hz.</p>
<p>The main differences between the methods of ISO 15186-1 and ISO 15186-3 are that in ISO 15186-3</p>
<ol><li>the sound pressure level of the source room is measured close to the surface of the test specimen, and</li><li>the surface opposite the test specimen in the receiving room is highly absorbing and converts the room acoustically into a duct with several propagating cross-modes above the lowest cut-on frequency.</li></ol>
<p>The results found by the method of ISO 15186-3 can be combined with those of ISO 140-3 and ISO 15186-1 to produce data in the frequency range 50 Hz to 5 000 Hz.</p>
<p>The reproducibility of this intensity method is, for all frequencies, estimated to be equal to or better than that found with the method of ISO 140-3 at 100 Hz.</p>
<p>Some comparisons of data obtained with this part of ISO 15186 and with ISO 140-3 are given for information.</p>
Registration number (WIID)
31395
Scope
<p>ISO 15186-3:2002 specifies a sound intensity method to determine the sound reduction index and the element-normalized level difference of building elements at low frequencies. This method has significantly better reproducibility in a typical test facility than those of ISO 140-3, ISO 140-10 and ISO 15186-1. The results are more independent of the room dimensions of the laboratory and closer to values that would be measured between rooms of volume greater than 300 m<sup>3</sup>. ISO 15186-3 is applicable in the frequency range 50 Hz to 160 Hz but is mainly intended for the frequency range 50 Hz to 80 Hz.</p>
<p>NOTE For elements faced with thick, porous absorbers, the recommended frequency range is 50 Hz to 80 Hz.</p>
<p>The main differences between the methods of ISO 15186-1 and ISO 15186-3 are that in ISO 15186-3</p>
<ol><li>the sound pressure level of the source room is measured close to the surface of the test specimen, and</li><li>the surface opposite the test specimen in the receiving room is highly absorbing and converts the room acoustically into a duct with several propagating cross-modes above the lowest cut-on frequency.</li></ol>
<p>The results found by the method of ISO 15186-3 can be combined with those of ISO 140-3 and ISO 15186-1 to produce data in the frequency range 50 Hz to 5 000 Hz.</p>
<p>The reproducibility of this intensity method is, for all frequencies, estimated to be equal to or better than that found with the method of ISO 140-3 at 100 Hz.</p>
<p>Some comparisons of data obtained with this part of ISO 15186 and with ISO 140-3 are given for information.</p>
