The Difference Between Laboratory and Site Sound Testing

The Difference Between Laboratory and Site Sound Testing

Many suppliers of acoustic insulation products quote laboratory sound test results  to demonstrate the performance of their systems. This often causes considerable confusion regarding how well products will perform as there are usually large differences between the laboratory and site conditions. For instance laboratory sound tests do not take account of flanking sound and therefore produce sound insulation figures that would be very difficult to achieve on site.

sound testing

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 also a contributing factor 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 due to time constraints etc. and so a design which can be easily in excess of the requirements of approved document E, can often lose approx. 8-10dB compared to the laboratory results. Unfortunately there may be many reasons for poor sound test results such as poor quality site installation as well as other on-site issues where cost, time and programming constraints may come into play.

architect drafting a house blueprint

architect drafting a house blueprint

One important thing to consider is that most building structures will be subject to varying amount of flanking sound, so field sound test data should show the real performance of a system in a building. Laboratory sound insulation tests simply measure sound and do not account for flanking sound transmission.

If you are worried about your projects acoustic design and/or have questions about the precompletion sound testing, please don’t hesitate to contact us now at: info@aptsoundtesting.co.uk or Darren direct on 07775623464. 

How to Improve your Sound Test Results

How to improve your Sound Test Results

If you have started a new or conversion development, it is important that from the offset you realise that you will need to comply with stringent sound insulation requirements of Approved Document E. Both new and converted residential dwellings use must meet the standards stipulated in Approved Document E. Part E states that the separating floor partition (floor between two separate dwellings) must achieve sound insulation figures of 45dB for airborne sound and 62dB for impact sound on all new builds and 43dB for airborne sound and 64dB for impact sound on converted dwellings; if you don’t achieve the aforementioned results then you will pass the sound testing. 

Building Control will expect you to demonstrate compliance with Approved Document E 2003 by undertaking an independent sound insulation test to prove that you have met the standards for sound insulation between dwellings.

Sound_Insulation_Testing_Equipment

The sound testing must only be carried out by either UKAS or ANC approved companies. If the sound tests are not carried out by approved compaines then Building Control may not accept the sound test report and subsequently it may need to be undertaken again by an approved company costing more time and money.

We are UKAS accredited to undertake sound insulation testing as well as air tightness testing. We offer design advice to help our client achieve Part E sign off. In some cases clients instruct us to proceed with the sound testing, without having carried our any acoustic upgrades or remedial works often resulting in their partitions failing the sound test.

Sound_Testing_Semi_Detached_House

If you are worried about passing your sound testing in London at the first attempt please don’t hesitate to contact us now at: info@aptsoundtesting.co.uk or visit our website at: www.aptsoundtesting.co.uk or call Darren Direct on 07775623464.

Reducing the Chance of Sound Testing failures

Reducing the Chance of Sound Testing failures

The simplest way to reduce the chance of sound testing failures is through careful consideration to the acoustic design at the start of the project.  Unfortunately, by simply specifying high performance wall and floor partitions, it is no guarantee to adequate sound isolation and successful sound testing at the end of the project.

We offer preconstruction design advice to help you achieve successful sound testing in-line with Building Regulations Part E. We also offer onsite inspection services to ensure that the sound insulation elements are being installed as per manufactures guild-lines, as it’s no use having good acoustic design if it not being installed properly on site.

architect drafting a house blueprint

Acoustic Design of Wall and Floor Partitions

The first stage of the acoustic design is to send through the design drawings – to include sections etc. We then review the design to check that the construction details proposed are capable of passing the sound tests. This usually takes place straight after planning has been approved as increased cost savings can be realised at the earliest stage, we will evaluate the construction methods and materials specified to ensure that they are capable of meeting the acoustic requirements of Approved document E. The typical areas we check are:

  1. There are no flanking points, where isolated partitions are wrongly mechanically fixed together to caused noise bridging.
  2. The walls and floors design are acoustically robust, to comply withBuilding Regulations Part E.
  3. The acoustic treatments for Soil Pipes, Stair Cases Steel Beams etc. to ensure they are acoustically fit for purpose, as these are some of the areas that get usually missed.
  4. Acoustic floor treatments are compatible with the proposed floor finishes i.e. Carpets, Laminates, Floor Tiles and under floor heating systems.

APT Sound Testing also provide on-going design support service, so you will have direct contact with the allocated acoustician from the start of the process through to the successful completion of the project. One of the most important services is the going site survey visits which allow our clients 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.

We also offer an acoustic advice service for clients that have failed their precompletion sound testing. We offer simple solutions to reduce the noise levels and achieve compliance with Part E. We can supply simple easy to follow acoustic design reviews, utilising our extensive knowledge of different materials and construction methods

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 Darren direct 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.

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

Noise Damping to Improve Sound Testing

Noise Damping to Improve Sound Testing 

Noise damping is the most efficient and effective ways to control vibration and noise radiation at the source. Damping materials lessen this noise by turning the vibration into a low-grade heat. By using viscoelastic materials, it changes the resonant frequency of a substrate. By combining vibration damping materials and sound absorbers a composite acoustic construction can be achieved, that can control both airborne and structure borne noise – the final element for good soundproofing.

acoustic_wall_upgrade

It is worth noting that a  large number of manufacturers now produce a wide range of systems designed to improve sound insulation in homes and commercial buildings. In all instances, the effectiveness of these materials will vary depending on the situation in which they are installed. When choosing the acoustic product/s, detailed information on the likely sound insulation performance should be requested from the supplier. If you have an existing property you should check the existing construction of the dividing wall/floor partitions and work back from there. You are advised to give careful consideration to the data supplied by a manufacturer before using a proprietary product. it is also worth noting that the sound insulation value/s given for each product will be ‘best case’ as they have been tested in laboratory conditions and not on site – this is usually worse result by up to 3-5 dB) which may be the difference between a sound test pass or failure.

acoustic_floor_roll_

Also when undertaking remedial work to improve the sound insulation, the acoustic materials are often quite heavy which may result in considerable weight being added to the structure of a property. Thus it is essential to check that the ceiling or floor joists can carry the increased loads satisfactorily.

So in a nutshell if you allow for the following four main elements of sound insulation on your acoustic partition design; Decoupling, Absorption, Mass and Damping, your development should pass the sound insulation test at the first attempt.

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.

Noise Absorption

Noise Absorption

It is usual for air cavities to resonate, such as the cavity within a timber wall. For instance if you blow across the top of a bottle and heard the sound, it sounds much louder; this is the trapped air resonating. In a similar way a hollow wall will also trap air that will resonate. When the wall is vibrated by loud sound such as a neighbour’s loud music of TV, the air in the wall cavity will vibrate just like a drum. Unfortunately this air cavity is another means for sound vibration to travel from one side of the acoustic partition wall to the other. So even though the wall framing may be decoupled, the vibrating air cavity may still transmit some sound through the wall between the wall studs. Acoustic fiberglass insulation will absorb some of this (absorption).

installing_acoustic_wool

In all instances acoustic Insulation should help the overall sound insulation test result, and should always be installed if possible. Although the vibration reduction is smaller than the other 3 elements it is still very important.  The key is to keep the density low, so don’t try to compress or pack the insulation as the vibration may use this to bridge the construction.

So to summarise we have now managed to de-couple and insulated the acoustic wall framing, which has helped to stop much of the vibration, but unfortunately not all of it. So what else can we do? – add mass of course. A full explanation of how mass can help your sound test results can be found in the next blog.

If you require any information on our acoustic design and/or sound test services, please contact us at info@aptsoundtesting.co.uk or call Darren 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.

The Main Sound Proofing Elements

The main Sound Proofing Elements

Coupled Wall Construction

We often get asked ‘how can we improve our soundproofing on our development. The first thing to understand is the basic of soundproofing design and construction. If you understand the basics, you’ll have a more educated view point in regards to the way sound and vibration behaves within your new dwellings. Basically, we want to stop sound and vibration through the walls and floors of your development and one of the best ways of doing this is avoiding coupled wall construction. In general, we are trying to stop vibrations from getting to “your” side of the wall or ceiling.

The plate below shows a typical wall and noise problems associated with it. With this type of construction noise transference is a big problem. If there is even moderate levels of noise on one side of the wall the chances are you will hear it.

coupled_wall_construction

If you look at the red arrows in the above diagram it clearly shows how sound is conducted from one side of the wall to the other. As the wall elements are firmly fixed against each other, i.e. the plasterboard is rigidly connected to the timber, the vibration conducts straight through the whole wall construction.

If you look at the blue waves this indicates airborne transmission. The plasterboard is vibrating back and forth which produces a sound wave in the wall cavity. This, in turn, vibrates the plasterboard on the opposite side of the wall. the whole construction acts like a  huge diaphragm or like a large speaker with both sides of the wall vibrating in unison, which is not ideal.

Our next blog will explain how we can reduce noise transmission by decoupling the wall construction. if you would like more information on our sound testing or acoustic design services please contact us now at: info@aptsoundtesting.co.uk or call Darren direct on 07775623464.