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 Intrusion Though Windows

Sound Intrusion Though Windows

Sound intrusion though windows can also be a source of great annoyance if the sound is excessive, and in some cases developments have failed the sound insulation testing due to poorly specified and installed windows. Sound intrusion may be down to a variety of factors. If the windows are operable types, the first thing to check is to see if the widows close properly against their seals and any weather stripping is continuous and in good order. If the window leaks air, then more often than not it will usually leak sound. If the window closes to form a tight seal and the weather-stripping seems adequate the next thing to check is the window frame. Windows are frequently installed in to the wall opening with plastic shims to insure the unit is plumb and level. In high traffic areas you will normally require a double glazed unit as a minimum and in some cases a triple glazed unit will be required.

Sound_Intrusion_Through_Windows

The space between the frame and the wall should be insulated and sealed before the window casings are installed. If this was not done correctly you can probably detect the sound leakage by placing your ear close to the frame and listening. The sound may be able to run along the cavity and back into the adjacent property, It is case of letting your ears do the walking and listening. If you detect distinguishable differences in sound you may have found the problem; the solution will be to remove the casing and insulate and caulk all leaks. In some cases the thickness of the glass maybe the problem in which case it may be necessary to install another layer of glass on the inside of the existing frame making sure that the additional pane of glass is well sealed into the opening.

In some instances you may be able to lower excessive sound by installing a heavy curtain – especially if the house is in a conservation area and as a result the local authority will not let you change or upgrade the windows.

If you require more advice on your project and/or you require precompletion sound testing, please contact us at: info@aptsoundtesting.co.uk  or phone me directly on 07775623464.

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.

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.

Noise Problems in Refurbished Industrial Buildings

Noise Problems in Refurbished Industrial Buildings

We often get asked to undertake a series of sound test measurements to establish the acoustic performance of the wall of floors construction in existing buildings where the dwelling owners are concerned about excess noise.

In recent years the refurbishment of old industrial buildings into residential dwellings has become a very popular. Frequently the existing finishes of existing concrete, brick or wood Noise Problems in Refurbished Industrial Buildingsare left as the interior finish, supposedly to provide the “loft” type of décor. Such designs require even more acoustic design attention if sound privacy is to be achieved. Potential noise problems in refurbished industrial buildings can be quite challenging so buyers should insist that actual on-site sound insulation testing is undertaken to check the building has complied with the sound design performance criteria of Building Regulations Part E.

sound_transmission_through_floors

If you think you have a sound problem in your dwelling and are seeking help to resolve the problem, be sure to contact us and describe the problem in as much detail as possible. Describe the nature of the sounds, when and where you can hear it. Is it impact noise or airborne noise or a combination of both? If the unit is of recent construction you may need to procure a set of architectural drawings and mark-up which partitions noisiest. The more information you can provide us, the quicker we can try to determine the nature of the problem and subsequently find an acoustic solution for the partition/s.

We can also visit site and undertake sample testing on the dividing partitions. If the partitions fail the tests we can identify the main reasons for the sound test failures so targeted remedial treatments can be undertaken.

If you have a project that requires acoustic design advice or sound insulation testing, then please contact us at: info@aptsoundtesting.co.uk or phone me directly on 07775623464.

 

Sound Transmission Though Windows

Sound Transmission Though Windows

One source of great annoyance is often due to sound transmission though windows, this can be down to a variety of factors. If the windows are operable types, the first thing to check is to see if the widows close properly against their seals and any weather stripping is continuous and in good order. If the window leaks air, then more often than not it will usually leak sound. If the window closes to form a tight seal and the weather-stripping seems adequate the next thing to check is the window frame.

Noise_Problems_Failed_Sound_Testing

Windows are frequently installed in to the wall opening with plastic shims to insure the unit is plumb and level. The space between the frame and the wall should be insulated and sealed before the window casings are installed. If this was not done correctly you can probably detect the sound leakage by placing your ear close to the frame and listening.

Usually double pane windows have poor noise-stopping capabilities. This may be overcome by installing a layer of lamination. Many manufacturers offer this service but it can be quite costly. Although double pane windows do stop a bit more noise than single pane windows it is still not very effective. In a noisy environment, you would hardly notice the difference.

Part of the problem is down to the construction of double pane windows; this is because the two pieces of glass are coupled within the same frame and vibrate together, similar to a tuning fork. Sound insulation, however, is increased markedly by using a double pane system and replacing air by argon between the panes.

In some cases the thickness of the glass maybe the problem in which case it may be necessary to install another layer of glass on the inside of the existing frame making sure that the additional pane of glass is well sealed into the opening.

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