To plan for further possible testing
Depending on the situation, the acoustic consultant might recommend testing specific solutions because:
- They have never been tested.
- They have been tested but some performance data or details are missing.
- They have been tested, but not under the right conditions.
This is more likely to happen for timber buildings, especially when the solutions are related to sound insulation design.
It is known that, in controlling the sound insulation within timber buildings, some materials have a different efficiency on timber structures than on masonry structures.
In other words, if a material has a certain performance on a masonry construction, it doesn’t mean it will achieve the same performance on a timber construction. So you could need to re-test the material on a timber construction. (resilient layers, that help control the impact sound insulation of floor constructions, are probably the best example).
Also, a material/product might have already been tested, but the data or the testing methods are limited.
It is usually the case for the frequency range considered that doesn’t go below 100 Hz, when acoustic designers need data down to at least 50 Hz (if not 20 Hz).
For impact sound insulation testing, it is good to use a calibrated impact ball (as well as the traditional tapping machine) which is not often used to test masonry floor constructions.
Finally, we know that the sound insulation performance of mass timber elements can dramatically vary with the mounting conditions (i.e. fixings, spans and also spacing between structural elements). If the proposed mounting conditions hugely differ from those already tested, it might be necessary to undertake more tests (in a lab or on-site).