Labouratory and Onsite Sound Testing

We at APT often get asked why an acoustic design that has passed easily in the laboratory has struggled – and sometimes failed to pass the sound testing for Part E.

Unfortunately, despite site contractor’s best endeavours, it is extremely difficult to build to the stringent exacting standards of the test laboratory. When the construction assembly is undertaken in the lab, it has gone through an exacting installation technique prior to the sound test, which is the reason why better sound testing levels are achieved.

Throughout the acoustic installation the manufacturer’s guidance is followed to the letter by the lab technicians. Although, this should be replicated on site, it seldom is and so a design which can be robust and well in excess of Part E requirements can lose 10dB or more compared to the results achieved in the laboratory.

Unfortunately there are many reasons why this occurs and it’s usually down poor quality operatives and other on-site other issues such as cost, time and programming constraints come into play.

We have undertaken many sound tests where the acoustic design details showed the partitions should achieve in excess of 50dB, only for it to fail with sound test results below the required 45dB. This is why a 7-9dB tolerance should be allowed between the dB rating of the acoustic solution and the onsite construction.

Unfortunately, if cost constraints come into play and subsequent allowances aren’t made for the onsite acoustic performance there is a high probability it will fail the sound testing, which may lead to expensive remedial works as well as delayed handover which will be far more expensive in the long run.

There are many reasons why the onsite construction results are worse than the laboratory, issues such as such as using the wrong fixings and not installing the insulation to name but two. Either of these can easily lead to a sound test failure.

It is very important that acoustic installation details are closely followed to ensure that the onsite results are as close as possible to the laboratory target. We offer an acoustic design service, to help you achieve Part E compliance at the first attempt.

The following list explains what should be done to achieve a successful sound tests and Part E compliance:

1.Ensure that the construction team is fully briefed of the acoustic details.
2. Ensure that the manufactures installation booklet is on site at all times.
3. Ensure that the Acoustic floor is fitted with staggered joints.
4. If you are installing floating screed ensure all isolation layer joints are overlapped and taped.
5. Ensure all the Acoustic floor is sealed watertight even around heating pipes.
6. Do not nail or screw through an Acoustic Floor.
7. Do not screws plaster board into joists, when using a Resilient Bar system.
8. Ensure the insulation fills the whole width of void.
9. Pack around pipe work and double board with staggered joints.
10. Ensure that the plasterboard on any walls is complete right down to within 5-10mm of the subfloor and seal all gaps.
11. Ensure you use the isolation tape around the wall of each room.
12. Ensure plasterboard is fitted with staggered layers and all joints sealed.
13. If using Resilient Bars ensure that they are fitted as per manufacturer’s recommendations.
14. Ensure all Fireplaces are blocked up with brick or a twin lined plasterboard system and filled with acoustic insulation.
15. Ensure that any RSJ’s or supporting steel work is insulated and isolated from plasterboard.
16. Ensure all waste pipe service runs are boxed in with insulation and plasterboard.
17. Ensure all doors and windows are installed before the test is carried out, to stop noise transference.

APT Sound Testing offers an acoustic design service to make sure the acoustic elements are being installed as per the manufacturer’s guidelines, if you are worried about passing your sound testing at the first attempt please don’t hesitate to contact us now by emailing us at