Section 4 of Technical Guidance Document E describes a test method to be employed in order to establish whether a particular construction present in one development, will be suitable for use in another development. A table sets out guideline sound transmission values that should be achieved under test if the acoustical performance is to be deemed acceptable for these purposes. In the absence of any other form of objective guidance, these values are often employed as a basis for assessing sound insulation performance. The contents of the table relevant to the tests performed in this case are reproduced below.
| Type of Performance || Individual Values || Mean Values |
| || ||Tests in at least four |
pairs of rooms
|Tests in at least eight |
pairs of rooms
|Airborne sound*(Minimum Values) ||49dB (walls) ||53dB (walls) ||52dB (walls) |
|48dB (floors) ||52dB (floors) ||51dB (floors) |
|Impact Sound**(Maximum Values) ||65dB (floors) ||61dB (floors) ||62dB (floors) |
* Airborne Sound - Weighted Standardised Level Difference (DnT,w)
** Impact Sound – Weighted Standardised Sound Pressure Level (LnT,w).
When testing at least four examples of a wall/floor construction, it is suitable to assess the sound insulation of individual wall/floor constructions in relation to the "Individual Values" above, but subject to the mean value of the test achieving the relevant "Mean Values" above. To ensure compliance with the Buildings Regulations (1997) when there have been tests on at least four examples of a wall/floor construction, individual values should be no less than 49dB (DnT,w) for walls and 48dB (DnT,w) for floors with the mean of all the tests achieving a minimum measured airborne sound insulation of 53dB (DnT,w) airborne for walls and 52 (DnT,w) airborne for floors, impact 65 dB (LnT,w) individually and a mean of 61dB (LnT,w) for floors (only).
The methods as listed in TGD Section "E" 1997 for such testing of walls and floors, with the reporting of results to same, have been superseded by the following:-
- Airborne Testing of Walls & Floors to- BS EN ISO 140-4: 1998 "Field Measurements of Airborne Sound Insulation between Rooms"
- Impact Testing of Floors to- BS EN ISO 140-7: 1998 "Field Measurement of Impact Sound Insulation of Floors"
- Calculation of Airborne Results to- BS EN ISO 717-1: 1997 "Rating of Sound Insulation in Buildings and of Building Elements - Airborne"
- Calculation of Impact Results to- BS EN ISO 717-2: 1997 "Rating of Sound Insulation in Buildings and of Building Elements - Impact"