We have undertaken many façade sound tests to ISO 140 Part 5. Unfortunately in our experience many of the new buildings are struggling to achieve a rating of 40dB, which makes a mockery of Part E as you need to achieve a minimum of 43dB and 45dB for sound testing on refurb and new build dwellings.
This image below shows how a Facade sound test is undertaken.
Often simple upgrades such as the replacement of double to triple glazing can reduce the level of external noise (termed background noise) entering the dwelling. As such, there may be less background noise breaking through the building facade thus lowering the chance of noise disturbance.