BS EN ISO 140-4: 1998 and BS EN ISO 140-7: 1998 describe the procedures for conducting airborne and impact sound insulation testing.
Table 2. Rooms for residential purposes – performance standard for separating walls, separating floors and stairs that have a separating function.
Airborne sound testing (BS EN ISO 140-4: 1998)
To test the airborne sound insulation performance of a wall or floor, a sound source is set up on one side of the wall or floor being tested. The sound source consists of an amplifier and a loud speaker which produces pink noise. Pink noise (similar to white noise) is used because it is made up of all sound frequencies, giving an indication of performance for a wide range of sounds that may be experienced within a dwelling, e.g. TV, conversation, washing machine, vacuuming, etc.
This pink noise is then measured on both sides of the wall or floor being tested. The difference between the two levels recorded is the amount of sound stopped by the wall or floor. The result is then corrected and adjusted depending on the reverberation time of the rooms (the time taken for sound to decay by 60dB), and any background noise, to give the airborne sound insulation result.
Impact sound testing (BS EN ISO 140-7:1998)
To test the impact sound transmission performance of a floor, a tapping machine which simulates footfall, is placed on the floor. The resultant noise in the room below is measured with a sound level meter and the amount of noise that passes through the floor is the impact sound transmission level. This result is then corrected and adjusted depending on the reverberation time of the rooms (the time taken for sound to decay by 60dB), and any background noise to give the impact sound transmission result.
The results of airborne sound insulation and impact sound transmission are compared to the performance criteria stipulated in Approved Document E (ADE) of the Building Regulations. It is the performance criteria within the Approved Document E that determines whether a building passes or fails.
These two tests are compared to the performance criteria of Approved Document E and a pass or fail certificate is produced, (see tables 1 and 2).
Table 1. Dwelling houses and flats – performance standard for separating walls, separating floors and stairs that have a separating function.