NOISE FLANKING ON YOUR PROJECT

NOISE FLANKING ON YOUR PROJECT

If you fail your Sound Test, you first you need to understand how the sound is travelling into your home. It may be coming directly through the separating partition, i.e. wall or floor or it may be coming along another indirect route – called a flanking path. The most common such flanking path is the inner leaf of an external cavity wall.

http://www.youtube.com/watch?v=edhLno7LFzY

 Problems with airborne and structure borne sound are often associated with direct flanking transmissions through floors and supporting walls and other associated structures. It is essential to establish if your problem is due to direct transmission, flanking transmission or a combination of both so that the most effective remedial treatment can be chosen. If you are unsure where the sound is getting through, then contact us at info@aptsoundtesting.co.uk  as we should be able to identify the worst areas by undertaking sound testing on the problematic partitions.

NoiseFlankingWall

 Unwanted noise travelling along flanking paths makes the building structure vibrate and this causes the sound to radiate into your room. One solution is to build another wall or ceiling in front of the original, but not connected to it (often called an independent wall or ceiling). A basic description of this treatment is given below.

There are two distinct types of noise to consider through floors, they are:

  • Airborne Noise (for example speech and music) and
  • Impact Noise (for example footsteps directly on the floor above) and

Even if both types of sound are emitting through the ceiling/floor then there are some easy installations that should reduce the sound levels and improve your sound test results.

If you would like more information in regards to sound testing please follow our blog at: http://soundtestinguk.blogspot.co.uk/, or contact us at: info@aptsoundtesting.co.uk or visit our website at: www.aptsoundtesting.co.uk

SOUND TESTING – QUESTIONS AND ANSWERS

SOUND TESTING – QUESTIONS AND ANSWERS 

Please find our list of Sound Testing common questions and answers, to help you prepare for the sound testing:

Q. How do I know if my project is ready for a sound insulation test?

  1. A.    All plots should be at least at second fix stage – for further details please refer to our sound testing checklist

Q. Will the sound testing disrupt other site works?

  1. During the sound testing, high levels of noise are generated but in order to make accurate test measurements, relatively quiet conditions are needed. Anyone working in the testing area will have to leave temporarily and any noisy works in the vicinity of the test rooms will need to be halted. The time taken for sound testing varies with the site conditions, but generally a set of tests on houses and flats takes about one to two hours so it’s over fairly quickly.

Q. Do I need to inform my neighbours of the sound testing?

  1. If the building under test is attached in any way to occupied properties then you will need to inform the neighbours. To comply with Part E we need to gain access to the neighbouring properties to undertake the sound test. You will need to ensure that access is provided to the neighbouring properties throughout the sound testing.

Q. Will all internal and external doors and windows need to be fully installed?

A. Yes, all internal and external doors must be fitted and operable prior to the sound testing

Q. What if I only have 110 volt on site?

A. Unfortunately we cannot undertake the testing; we will need 240V to undertake the sound testing.

Q. Can you offer advice on how to pass the sound testing?

  1. Yes, we can offer an acoustic design advice service. If you send through the relevant drawings such as sections, plans etc. during the earlier stages of construction, we can look at your design to check if the design is robust enough to pass Part E and/or there are any junctions or details where ‘noise flanking’ may occur. You can then change your design to reduce the chance of a sound test failure.

Q. Do you have a check-list we can download to help us prepare for the sound test.

A. Yes we do, please click on our sound test checklist; this should help you prepare for the testing.

If you would like more information in regards to sound testing please follow our blog at: http://soundtestinguk.blogspot.co.uk/, or contact us at: info@aptsoundtesting.co.uk or visit our website at: www.aptsoundtesting.co.uk

WHAT SOUND LEVELS DO I NEED TO PASS MY SOUND TESTING?

WHAT SOUND LEVELS DO I NEED TO PASS MY SOUND TESTING?

To help you better understand the sound level requirements of Part E of Building Regulations to pass your Sound Testing, we have collated an easy to follow table – shown below.

Table 1a: Dwelling-houses and flats – performance standards for separating walls, separating floors, and stairs that have a separating function.

Airborne sound insulation
DnT,w+Ctr dB
(Minimum Values)

Impact sound insulation
L’nT,w dB
(Maximum Values)

Purpose built
Walls
Floors and Stairs

45
45

N/A
62

Material change of use
Walls
Floors and Stairs


43
43


N/A
64

 

Table 1b: Rooms for residential purposes – performance standards for separating walls, separating floors, and stairs that have a separating function.

Airborne sound insulation
DnT,w+Ctr dB
(Minimum Values)

Impact sound insulation
L’nT,w dB
(Maximum Values)

Purpose built
Walls
Floors and Stairs

43
45


N/A
62

Material change of use
Walls
Floors and Stairs

43
43


N/A
64

Basically, for new build properties you need to achieve 45dB or higher for airborne wall and floor sound tests and 62dB for Impact sound tests. For Converted properties the levels are slightly easier to achieve with 43dB for airborne wall and floor sound testing and 64dB for impact sound testing.

A brief description of the types of sound testing are:

AIRBORNE SOUND TESTS

Airborne sound tests may be required between horizontally and vertically separated pairs of rooms. 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.

IMPACT SOUND TESTS

For vertically separated rooms, an Impact sound test may also be required. This sound test is undertaken using a “tapping machine”, (as above) which drops a series of weights 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.

Impact Sound Testing

If you would like more information in regards to sound testing please follow our blog at: http://soundtestinguk.blogspot.co.uk/, or contact us at: info@aptsoundtesting.co.uk or visit our website at: www.aptsoundtesting.co.uk

ACOUSTIC DESIGN CONSULTANCY

Acoustic Design Consultancy 

On all new construction projects its extremely  important that checks are undertaken on the acoustic design from the initial design stage through to completion.

Acoustic Design Advice

We at APT Sound Testing offer a no nonsense professional proactive approach to all aspects of the acoustic design with initial onsite surveys to check the acoustic detailing  is being  installed correctly along with the final sound testing. This ensures your company receives professional advice every step of the way, with an on-going continual consideration of cost.

Acoustic Design & Detailing

We have considerable experience in all matters related to architectural acoustic design and detailing. We can help develop the initial acoustic design of the project from the initial design scheme stage, in particular acoustic isolation, and interior acoustics. We also use the latest Norsonic equipment analysers and sound sources for conventional and binaural acoustic measurements.

Site Survey Visits

We offer site survey visits which allow you (the client) and your contractor to feel confident about the outcome of testing at the end of the build. The site visits let us check that the installation teams are installing the acoustic materials as per manufacturers avoiding crucial onsite mistakes. You can often have a compliant design which still fails due to poor workmanship; the site survey visits negate the risk of sound test failure.

http://www.youtube.com/watch?v=kjTzgxS8HvI

Simple Design Considerations

  • The use of suspended ceilings will help improve the performance of the floor partition.
  • Including a resilient acoustic layer or adopting an “acoustic” flooring system will improve the impact and airborne performance of a floor
  • Avoid using lightweight blocks in the inner envelope construction as sound will travel along these both vertically and horizontally from dwelling to dwelling.

Defect Diagnosis & Remedial Advice

Occasionally we get involved in construction projects that have failed the sound testing, even though we weren’t involved from the beginning. Often it is due to the inclusion of inadequate materials or the exclusion of the necessary materials.

ACOUSTIC_DESIGN

With over 30 years’ experience in building acoustics, we are able to diagnose the reasons for the sound test failure and recommend a cost-effective solution. Often, the reasons for the partition failure are obvious to the test engineer in which case the advice will be minimal and subsequently costs will be minimal. Sometimes, there are more technical issues which require detailed diagnosis and invasive investigation, such as a serious design fault, e.g. the use of lightweight blocks throughout the inner envelope wall on a block of flats.

Whatever the problem we can usually find an acoustic solution that will provide a sufficient acoustic design to satisfy Part E of Building Regulations. If you have a sound test failure then get in touch with us as soon as possible as we should be able to offer you an expedient solution helping you to achieve practical completion in the quickest time possible.

This why we at APT Sound Testing place such emphasis on the process of ‘expert intervention’.

If you would like more information in regards to sound testing or acoustic design, please follow our blog at: http://soundtestinguk.blogspot.co.uk/, or contact us at: info@aptsoundtesting.co.uk or visit our website at: www.aptsoundtesting.co.uk