The new performance requirements are considerably more stringent than those set out in the 1991 Edition. This is due to the addition of a low frequency correction factor (Ctr), which is applied to the airborne sound insulation values.
As a consequence, the new values will be more difficult to achieve for many conventional types of constructions. Section E2 to E8 of the approved document gives examples of types of construction likely to meet the performance requirements.
In all cases, good design and installation practice should be followed. It is important that measures to eliminate or minimise flanking sound transmission are employed at the design stage and the builder installs the specified products correctly. Failure to do so may lead to limitation of acoustic performance and the requirements of the Building Regulations not being met.
When attempting to make any sort of construction compliant to the Part E Regulations, it is important to note that sound does not always go straight through the building element. If the wall or floor concerned has good sound reducing capabilities then the sound will simply find the easiest way around it. In short, if the sound can’t go through the wall, it will go up and over or around the side. This is called Flanking Transmission and occurs when sound travels along elements shared by adjacent structures. If measures to tackle Flanking are not correctly specified or constructed, Flanking Transmission can exceed direct transmission and damage the overall capabilities of the construction. One way of dealing with this issue is to use isolation strips around the perimeter edges of floors and walls, as well as the use of an acoustic sealant wherever possible.