Sound Insulation Testing on House and Flats
Sound Insulation Testing is undertaken near the end of a project to show that the party wall and floors meet the Building Regulations Part E stipulated. The method for sound testing for airborne and impact sound insulation is in full accordance with the suggested methods presented in BS EN ISO 140-parts 4 & 7: 1998.
Detached houses don’t require sound insulation testing, however if the house has been built on to the end of an existing house and/or terrace it usually requires 2 airborne wall tests, one test on the lower floor which is usually the living room ad a second test on the 1st floor through the bedroom walls.
Apartment blocks usually require airborne and impact sound insulations tests. Airborne sound testing is normally required between horizontally and vertically separated pairs of rooms i.e. the wall and floor partitions. The sound tests are undertaken by using a sound source, amplifier and loudspeaker to generate a high noise level in one room (the source room). Noise measurements are then taken in both the source and receiver rooms using a prescribed number of source and microphone positions. The background levels in the receiver room are measured and the reverberation time in the receiver room is also measured. From the results, the airborne sound insulation (DnT,w + Ctr) is calculated and compared to the requirements of Approved Document E.
Sound Testing on Flats
When undertaking sound testing for floors, impact sound testing may also be required for vertically separated dwellings. Impact sound insulation testing is undertaken using a “tapping machine”, which drops a series of weights/small hammers onto the floor of the upper room. The noise level in the lower (receiver) room is measured for a prescribed number of source and microphone locations. The background levels in the receiver room are measured and the reverberation time in the receiver room is also measured. From the results, the impact sound insulation (L’nT,w) is calculated and compared to the requirements of Approved Document E.
When it comes to refurbishment projects i.e. office block converted into flats or large house subdivided into dwellings, we can undertake a sample sound test of the existing wall and floor construction. Once we have established the sound levels for the existing construction we can then look at extent of the acoustic upgrades to attain Part E Compliance. This is much more targeted way to formulate a more cost effective and accurate acoustic design as we know the sound insulation performance of the existing partitions.
The sound insulation levels required to pass Part E are usually 45dB for airborne wall and floors and 62dB for Impact Sound Testing on new build, however sometimes a higher target may be required in-line with the Code for Sustainable Homes; this is usually in defined in the following figures +3, 5 & 8dB, this means if its plus 5dB you will need to achieve 50dB for airborne and 57dB for impact sound testing. Obviously if you need to comply with the Code for Sustainable Homes then special attention must be shown to the acoustic design from the offset to reduce the chance of sound testing failure.
The amount of sound testing you require depends on the size of the development. All new build properties and conversions require 10% of each party wall/floor construction type to be tested, i.e. if you have built a pair of semi-detached houses you would be required to undertake 2 airborne wall tests. If you have up to 10 flats you would require 1 x 6 pack, consisting of 2 airborne wall, 2 airborne floor & 2 Impact sound tests – known as a 6 pack) However if you have 11 units this would rise to 12 Sound Tests or 2 x 6 pack. Also, if you have many different wall or floor types you will be required to undertake more tests to satisfy Building Regulations Part E.
Some ways you can improve the chances of passing your sound test at the first attempt, they are:
- Ensure all penetrations are fully sealed where they terminate through floors and they are adequately boxed with acoustic quilt and two layers of plasterboard.
- Avoid the use of lightweight blocks in the inner envelope construction as sound will travel both vertically and horizontally from dwelling to dwelling.
- The use of resilient suspended ceilings will help improve the performance of the floor partition.
- Ensure all support steels/timbers are carefully boxed out where they travel from flat to flat vertically and horizontally.
- Use a high quality resilient acoustic membrane on top of the floor to improve the impact performance of a floor.
Due to the overwhelming variety of material designs and combinations due to varying constructions, it is impossible to cover all problems in a short article such as this; however in our experience if the acoustic design is taken into consideration from the offset of the project, then it usually results in a successful sound testing and compliance with Building Regulations Part E.
If you have a project that requires sound testing in London then contact us now, we can propose a sound testing schedule that should comply with Part E. Please contact us at: email@example.com or call us at 07775623464