Curtain Walling: Flanking sound transmission
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Principles
Flanking sound transmission is the ability of a curtain wall to mitigate the spread through the façade of noise produced in an adjacent space. Where required the flanking transmission should be determined by test in accordance with EN 10848-1 and -2. The flanking sound transmission in the vertical and horizontal direction has to be distinguished. The test results shall be rated according with EN 717-1.
Flanking sound transmission is not covered by the existing Product Standard. It will be a requirement of the revised Product Standard.
Standards
| EN 717-1 | Acoustics – Rating of sound insulation in buildings and of building elements – Part 1: Airborne sound insulation |
| EN10848-1 | Acoustics – Laboratory measurement of the flanking transmission between adjacent rooms, the noise emitted by air and sound insulation – Part 1: Framework Document |
| EN10848-2 | Acoustics – Laboratory measurement of the flanking transmission between adjacent rooms, the noise emitted by air and sound insulation – Part 2: Test on elements come to light in the case of weak influence |
Method of test
Flanking transmission is assessed by installing a junction between two test rooms in a way that minimises the direct sound transmission, and measuring the sound level in the receiving room over a range of frequencies. The test is carried out with an airborne noise source and an impact noise source.
Classification
There is no classification for flanking transmission. Where required the values should be declared in units of dB.
CE Marking
Regulations apply to noise transmission between dwellings, and rooms for residential purpose, which includes student accommodation and hotel rooms. This is mainly dealt with by using a wall/floor with a suitable performance, however flanking transmission/interfaces are also included. The flanking transmission depends on internal wall and floor details (fit out, suspended ceilings, raised floors etc) and is therefore out of the curtain wall contractors control. The allowable use of No Performance Determined (npd) is as follows:
| Location | npd allowed |
| England and Wales | Probably |
| Scotland | Probably |
| Northern Ireland | Probably |