Acoustic Terminology A-B

Acoustic Terminology A-B

Often confusion can arise from the large amount of ‘terms’ used in conjunction with acoustic design and sound insulation testing. To help with this we have made a list of the following terms along with a quick explanation:

 Absorption

This is the conversion of sound energy into heat, often by the use of a porous material.

Absorbent Material

This is a material that absorbs sound energy, such as acoustic mineral wool.

Airborne sound

This is sound which is propagated from a noise source through the medium of air. Examples of these are speech and sound from a television

Airborne Sound Transmission

This is direct transmission of airborne sound through walls or floors. When sound energy is created in a room, for instance by conversation, some of the energy is reflected or absorbed by room surfaces but some may set up vibrations in the walls and floor. Depending on both the amount of energy and the type of construction, this can result in sound being transmitted to adjacent parts of the building.

Air Path

This is a void in construction elements, which adversely affects the performance of sound resisting construction. Examples of air paths include incomplete mortar joints, porous building materials, gaps around pipes and shrinkage cracks – this can also effect the air tightness results.

 Bonded resilient cover

This is a thin resilient floor covering normally of minimum 3-5mm thickness, which is bonded to the isolated screed surface to reduce impact sound transmission such as footfall noise, however it has a lesser effect when it comes to airborne noise.

Acoustic_Site_Survey

If you have a project that requires acoustic design and/or sound testing please let us know. APT Sound Testing will ensure you will have direct contact with the allocated acoustician from the start of the process, through to the successful completion of the sound insulation testing.

If you would like more information in regards to acoustic services, please contact us at info@aptsoundtesting.co.uk or visit our website at: www.aptsoundtesting.co.uk

Our Acoustic Services

Our Acoustic Services

APT Sound Testing offers a full turnkey solution for all your acoustic requirements to ensure compliance with Building Regulations Part E and achieve building control sign off for the acoustic elements of the project. This ensures your company receives professional advice every step of the way, with an on-going continual consideration of cost.

Our acoustic services consist of the following elements:

Sample Sound Insulation Testing

We visit site to undertake sample sound testing to the existing buildings walls and floors to check the sound insulation performance of the existing dividing partitions. Thereafter, once the sound levels have been established and targeted acoustic design can be undertaken to ensure compliance with Building Regulations Part E.

sound testing equipment

Acoustic Design Service

We can help develop the acoustic design of the project from the initial design scheme stage through to the precompletion sound testing. In particular we review the acoustic details to take into account the mass, isolation and absorption elements of the construction.

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.

Acoustic_Site_Survey

Sound Test Failures

If your building fails the sound testing, we can use our experience in building construction and acoustics to firstly diagnose the reasons for the sound test failure and thereafter recommend a cost-effective solution to allow you to achieve building regulation compliance.

If you have a project that’s needs acoustic design advice or sound testing in London, then please contact us at: info@aptsoundtesting.co.uk or phone us directly on 07775623464.

Good Acoustic Design Considerations

Good Acoustic Design Considerations

In our experience careful consideration to acoustic design should be undertaken from the start of the project, if this process is followed it usually results in successful precompletion sound testing in compliance with Building Regulations Part E.

In many cases sound test failure can be down to the poor workmanship rather than acoustic design, that is why we offer a full acoustic package which includes for site survey visits; that way we you can be safe in the knowledge that you have the acoustic design and onsite construction covered, reducing the chance of sound test failure.

sound testing equipment

Here are some simple acoustic design tips:

  • Ensure all penetrations are fully sealed where they terminate through floors and they are adequately boxed with acoustic quilt and two layers of plasterboard.
  • Use resilient acoustic hangers within the ceiling design to provide isolation between materials.
  • Avoid the use of lightweight blocks in the inner envelope construction as sound will travel both vertically and horizontally from dwelling to dwelling.
  • 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.

In our experience by simply designing and constructing a good separating wall or floor it may not provide sufficient sound insulation to comply with Building Regulations Part E as the junctions of each separating wall and/or floor with other parts of the building are as equally important. One of the main problems with partition failure is down to noise flanking, this can occur via construction components such as:

  • The internal partitions
  • The inner leaf of the external wall
  • The external wall cavities
  • The external façade or outer leaf
  • The roof structure
  • The foundations.

Flanking sound transmission may in some cases be the dominant pathway between adjoining dwellings, especially in existing buildings where you are planning to convert offices/large houses into flats and lightweight materials have been used in the wall construction. If the acoustic consultant has not been made aware of the existing construction it may increase the chance of sound testing failures.

If you have a project that’s needs acoustic design advice or sound testing in London, then please contact us at: info@aptsoundtesting.co.uk or phone us directly on 07775623464.

The Two Types of Sound Insulation Test

The Two Types of Sound Insulation Test

There are two types of sound insulation testing, Airborne and Impact.

Airborne sound testing is undertaken to walls & floors. Firstly a controlled noise is generated by an amplifier and loudspeaker across a broad range of frequencies. The generated noise is very loud and is often in excess of 100dB. Initial measurements are taken using a class 1 sound level meter within the ‘source room’ followed by further measurements in the ‘receiver room’ on the other side of the wall or floor under investigation. The source room speaker position is then changed and the measurements repeated either side of the partition under test.

Sound_Insulation_Testing_Equipment

Thereafter background noise measurements are made using a class 1 sound level meter in the receiving room and are used to apply appropriate corrections for external sound such as traffic noise. Similarly the reverberation time (the time taken for sound to decay by 60dB) is measured within the receiving room using the sound source and a sound level meter to determine the corrections that must be applied to account for the absorptive characteristics of the room.

The difference in the two airborne noise levels (for walls and floors), corrected for background and reverberation characteristics determines the airborne sound insulation performance of the wall, or floor. A greater airborne noise difference between the source room and the receiver room determines a higher airborne sound insulation performance.

The time taken to undertake sound testing varies from project to project as no site is exactly the same. Taking into account standard site conditions a set of tests on houses -two airborne walls will take one to two hours. A six pack of tests on flats – 2 airborne wall tests will usually take between one and two hours, although this is dependent on our engineers having full free uninterrupted access between all the units/rooms under investigation.

If you require sound insulation testing, or acoustic design advice then please contact us now at info@aptsoundtesting.co.uk  or phone me (Darren) directly on 07775623464.

Why Have I Failed my Sound Insulation Test?

Why Have I Failed my Sound Insulation Test?

This is one of the most common questions clients ask when their property has just failed the sound testing. One of the main reasons for acoustic partitions failing the Part E sound test is often down to poor isolation of material/s, which can lead to excessive noise flanking. Noise Flanking is a term used by acoustic engineers to describe where sound passes through an acoustic partition due to the abutment of materials. The noise simply hits the one side of the wall and then travels through the construction via a noise bridge. This can be areas such as the incorrect use of masonry wall ties i.e. solid fishtail ties, used in place of specified acoustic wall ties; if your building suffers from noise flanking it may result in a sound test failure.

Sound_Insulation_Testing_Equipment

Unwanted noise travelling along flanking paths can make the building structure vibrate, which can cause sound to radiate into your room – as shown in the plate below . One simple cost effective solution is to build another wall or ceiling in front of the original, to offer extra isolation. For this upgrade to work you need to make sure that the independent wall or ceiling is not directly connected to the existing failed partition; so it provides isolation between materials.

Coupled_wall_construction

Noise flanking can also be down to the use of down to the use of lightweight blocks in the construction of the building envelope. Due to the lightweight mas of the inner wall it allows sound to transmit from dwelling to another, both vertically and horizontally. If a building has failed its sound testing, it is essential to establish if the problem is due to direct transmission, flanking transmission or a combination of both so that the most cost and time effective remedial treatment can be designed and applied to the failed partitions.

If you require more information about acoustic design and/or sound testing on your project, please contact us now at info@aptsoundtesting.co.uk or call me direct on 07775623464.

Sound Insulation Testing

Sound Insulation Testing

At APT we offer Airborne and Impact Sound Insulation Testing in accordance with Part E of the Building Regulations and, where required sound testing on Schools BB93 & BREEAM. Under Part E of Building Regulations, this is a requirement for new and converted dwellings where there is a separating partition wall or floor. The sound insulation testing of existing buildings is carried out to assess current levels of sound insulation and to allow for the design of remedial measures, where the performance needs to be increased.

The buildings that currently require sound testing are:

  1. Dwelling-houses, flats or rooms for residential purposes created by conversion of existing buildings or new build rooms for residential purposes will need to be tested if work starts after 1 July 2004.
  2. New build dwelling-houses and flats will need to be tested if work starts after 1 July 2004.

Sound insulation testing is carried out to ensure that minimum standards of sound resistance have been met to ensure the well-being of new tenants is not compromised by adverse sound transmission. The testing checks that the dividing partitions have not been compromised by poor workmanship and poor design. We use the latest sound testing equipment as shown below:

sound testing equipment

You are normally required to undertake sound testing to each type of construction, i.e. if you have a mixture of brick, block-work, timber and metal stud-work walls all four types would need to be tested, followed by a 10% sample of that type. it is worth noting that if any test failures occur, then the number of sound tests may need to increase on the development.

If you are unsure whether the Regulations apply to your development or if your site needs sound insulation testing, please call your local office or email us at info@aptsoundtesting.co.uk where our team will be happy to discuss all aspects of acoustics or sound insulation within buildings, and explain the testing procedure.

Simple Acoustic Upgrades

Simple Acoustic Upgrades

There are many simple acoustic upgrades you can undertake to improve the sound insulation values of your dwelling. Plate A below shows one cost effective ceiling upgrade that can be undertaken on conversion projects. Firstly retain the existing floor joists – check them for general wear and tare) then above the joists install 22mm chipboard. Above the floor board install an acoustic resilient membrane and above this install the 22mm engineered floor. Within the joist cavity install 100mm AW IsoWool. To the underside of the joists fix a resilient hanger system and below this install two layers of 12.5mm sound boards ensuring that boards have adequate laps. It is worth noting that although the above system should work, it is essential that you contact us before going ahead with any works as each project is different and may require extra acoustic design input.

Plate A – Acoustic Floor Upgrade

Good Conversion Diagram - 15-01-16Also, to try and help our clients achieve compliance with Approved Document E at the first attempt we offer the following 4 step acoustic design package:

  1. Site Survey Visits – to let us view the existing site construction. This allows us to check for potential problematic construction such as inclusion of lightweight blocks in the existing construction. It also lets us check that the installation teams are installing the acoustic materials as per manufacturer’s guidelines.
  2. Sample Sound Testing – of the existing construction. This offers an accurate overview of the acoustic performance of the existing partitions which enables us to offer a targeted acoustic design using the sound insulation performance of the existing construction.
  3. Acoustic Design Review – a full design review of the proposed developments party walls and floors.
  4. Pre-completion Sound Testing to satisfy Approved Document E.

APT Sound Testing can advise on all types of acoustic design, whether it’s accomplished during initial construction or during a refurbishment/renovation project. We also undertake UKAS accredited sound insulation testing providing a ‘one stop’ solution for all your acoustic requirements.

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 and 07775623464 or visit our website at: www.aptsoundtesting.co.uk

Sound Insulation Testing in London

Sound Insulation Testing in London

Unless plans were fully approved prior to 1 July 2003, sound insulation testing will be required on your London development between rooms or spaces that share a common area of separating wall and/or floor as stipulated in Building Regulations Part E for the passage of sound. Sound insulation Testing is not generally required for internal walls and floors within a dwelling-house, flat or room for residential purposes; however all internal partitions should be designed to achieve 40dB.

The buildings that require sound testing are:

  1. Dwelling-houses, flats or rooms for residential purposes created by conversion of existing buildings or new build rooms for residential purposes will need to be tested if work starts after 1 July 2004.
  2. New build dwelling-houses and flats will need to be tested if work starts after 1 July 2004.

The main aim of Sound testing in London is to ensure that minimum standards of sound resistance have not been compromised by poor workmanship and/or poor design. You are normally required to undertake sound testing to each type of construction, i.e. if you have a mixture of brick, blockwork, timber and metal studwork walls all four types would need to be tested, followed by a 10% sample of that type using the equipment shown in Plate A below.

Plate A – Our Sound Test Equipment.

sound testing equipment

For instance, if you have a project with 25 flats you would be required to do 3 x 6 pack of tests; each 6 pack contains 2 airborne wall, 2 airborne floor and 2 impact sound tests; however if any test failures occur, then the number of sound tests may need to increase on the development. When sound test failures occur, then the design and construction of the failed partitions will need to be revisited to try and evaluate the reasons for the failure; thereafter, agreement can be reached on how to rectify problem.

APT Sound Testing can advise on all types of acoustic design, whether it’s accomplished during initial construction or during a refurbishment/renovation project. We also undertake UKAS accredited sound testing providing a ‘one stop’ solution for all your acoustic requirements.

If you would like more information in regards to sound insulation testing please follow our blog at: http://soundtestinguk.blogspot.co.uk or contact us at: info@aptsoundtesting.co.uk and 07775623464 or visit our website at: www.aptsoundtesting.co.uk

Adding Mass to Improve Sound Insulation

Adding Mass to Improve Sound Insulation

Adding mass to improve sound insulation can be one of the most important elements to improving precompletion sound testing results. In summary it basically means you add extra weight/mass to the construction of the acoustic wall and/or floor partition. Materials such as solid block-work masonry is best for wall construction; however it is very important that the block-work envelope is constructed out of solid concrete block work as the use of lightweight block work often ends in sound test failure.

Sound_Insulation_Test_London

 For floor construction, solid concrete floors – min 150mm) are usually the best construction for outright mass; however soundboard, plywood and OSB can be found fairly cheaply and will also do the job – if installed as per manufacturer’s guidelines. It is very important that adequate site supervision is on hand to check the construction of all acoustic partitions.

It is basic physics, so for sound to conduct through a wall, it has to actually move (vibrate) the wall ever so slightly. As a heavier wall is harder to move than a lighter wall then it should vibrate less and turn let through less noise. Soundboard is one of the lowest cost sources of mass available and also one of the most commonly used. Wherever possible its best to use two layers of 12.5mm board with the correct laps to the boards. Although the wall will still vibrate it will be less due to the extra mass.

It’s worth noting that although the added mass improved things and it will be more difficult for sound to move this heavier wall, in many instances you will still hear low frequencies (bass noise) quite easily.

Our next blog covers the last – but not least) element of acoustic design – Damping. If you would like more information in regards to acoustic design and sound insulation testing, please contact us now at info@aptsoundtesting.co.uk or call Darren direct on 07775623464.

Decoupling of Materials

Decoupling of Materials

There are many things to consider with your acoustic design and construction, one of the first – and most important) is the decoupling of materials or also know as isolation of materials. Sound travels easily along direct construction pathways, i.e. if the construction is made up of a wooden wall frame with a layer of plasterboard fixed to either side, with this type of construction the sound has a solid mass of materials to travel across. If we “decouple the materials” it reduces the pathway for vibration and the sound levels drop accordingly.

When we design for acoustic partition construction we obviously want less sound vibration to travel from one side of the wall to the other. It is therefore hugely beneficial if we can decouple the partition framing in our walls and ceilings. Decoupling is a simple, inexpensive and highly effective way to improve the sound insulation results for Building Regulations Part E.  .

There are many types of decoupled construction that in turn offer varying degrees of separation of the drywall on one side from the drywall on the other side. For instance the image below shows a twin wall construction which is far superior to a single stud wall. if you require good sound test results, this is one of the best types of construction.

decoupled_wall_construction

By decoupling the wall studs limits by providing a cavity or break between the two walls reduces the vibration trying to conduct through the wall. although this will improves the airborne results, other improvements will still be required.  So although our decoupled framing system reduces a good deal of vibration, we need to continue to the other 3 elements, absorption, mass, and to damping to reduce the noise more effectively.

Our next blog will consider absorption and how it can make a  large difference to sound test results. If you would like more information to acoustic design and/or sound insulation testing please contact us at: info@aptsoundtesting.co.uk or call Darren on 07775623464.