The method can be used as an alternative to JIS A 1416 and JIS A 1428, respectively.

One important use is when the traditional JIS A 1416 method fails because of high flanking transmission.

The reproducibility of this intensity method is estimated to be equal to or better than that of JIS A 1416.

NOTES 1 Some information about the accuracy with which this part of JIS A 1441can reproduce the sound reduction index measured according to JIS A 1416 is given in Annex A.

2 The International Standard corresponding to this part of JIS A 1441 is as follows.

In addition, symbols which denote the degree of correspondence in the contents between the relevant International Standard and JIS are IDT (identical), MOD (modified), and NEQ (not equivalent) according to ISO/IEC Guide 21.

ISO 15189-1:2000 Acoustics – Measurement of sound insulation in buildings and of building elements using sound intensity – Part 1: Laboratory measurements (MOD)

The element method aims to obtain the apparent sound reduction index of a facade element, for example a window.

The global method aims to obtain the generallevel difference which responds to the incident condition of each noise source integrated into the whole room.

The measuring method having high reproducibility in the element method is that using a loudspeaker as the sound source, and the measuring method having high realistic sound insulation in the global method is that using the actual traffic as the sound source.

The overview of measuring methods is shown in table 1.

In the element loudspeaker method, the apparent sound reduction index comparable with the result measured in accordance with JIS A 1416 can be obtained.

The element road traffic noise method is useful when the element loudspeaker method cannot be used for some practical reasons, but it tends to result in lower values of the apparent sound reduction index than the loudspeaker method.

When the loudspeaker cannot be set outside, the method in which the loudspeaker is set in a room (inside sound source method) to obtain the level difference is available for the same purpose as the element loudspeaker method as shown in Annex JB; however, the correspondence of both methods has yet to be verified.

The global road traffic noise method yields the sound pressure level difference between a certain indoor place and a position 2 m or 1 m in front of the facade, and is used to obtain the real sound insulation between inside and outside of the room.

This method is used when the sound insulation including the effect of other sound source to the room of interest or the effect of all flanking paths relative to nearby roads is measured.

The element road traffic noise method and the global road traffic noise method are given in Annex JA.

The measuring methods using the aircraft traffic noise and the railway traffic noise are given in Annex D.

The global loudspeaker method yields the sound pressure level difference between the position 2 m or 1 m in front of the facade and the indoor position, and this method is useful when the real noise source is not available.

The results of these global methods cannot be compared with those obtained in accordance with JIS A 1416.

NOTE 1 The method for laboratory measurement of airborne sound insulation of building elements is specified in JIS A 1416.

NOTE 2 The method for field measurement of airborne sound insulation of wall between two rooms, floor, door, etc. in building is specified in JIS A 1417.

NOTE 3 The International Standard corresponding to this Standard is as follows.

ISO 140-5: 1998 Acoustics-Measurement of sound insulation in buildings and of building elements-Part 5: Field measurements of airborne sound insulation of faqade elements and faqades (MOD)

In addition, symbols which denote the degree of correspondence in the contents between the relevant International Standard and JIS are IDT (identical), MOD (modified), and NEQ (not equivalent) according to ISO/lEC Guide 21.

The evaluation method of the impact sound pressure level measured in accordance with this Standard is specified in JIS A 1419-2, using single number quantities.