Sound Insulation & Noise Flanking

Sound Insulation & Noise Flanking

Sound insulation & noise flanking describes the reduction of sound that passes between two spaces separated by a dividing element, such as a wall or floor partition. The sound energy passes through the dividing element (direct transmission) and through the surrounding structure (indirect or flanking transmission). The  noise reduction attributed to the sound insulation is realised via sound insulation testing.

 When the building’s acoustic design is taken into consideration, it is important to consider both methods of transmission. The dividing walls or floors, which flank/abut the dividing element/s, usually constitute the main paths for flanking transmission, but this can also occur at ventilation ducts, doorways, windows etc. If windows are positioned very close to the dividing partition then noise flanking will usually occur around the main building envelope, thus rendering your ‘high spec’ acoustic solution useless.

sound testing equipment

It is extremely unlikely that figures quoted from ‘laboratory sample’ sound test conditions will be achieved on site, as the laboratory installation is described in detail and followed to the letter. However, due to time constraints etc. it is not always possible to replicate the same conditions on a construction site, which is the reason why a 5dB point difference is allowed between the laboratory and construction site sound insulation performance.

Noise Flanking Paths

Flanking sound is defined as sound from a source room that is not transmitted via the separating building element e.g. the wall or floor partition. The sound is transmitted indirectly via paths such as external walls, windows, doors and internal corridors.

NoiseFlankingWall

If you would like more information on sound insulation testing and/or acoustic design service, please contact us at info@aptsoundtesting.co.uk or call us on 07775623464

Excess Noise Between Dwellings

The Reasons for Excess Noise Between Dwellings

There are a variety of reasons why sound insulation may need to be improved. Some of the typical reasons given by occupants, property managers and developers are:

  • Poor workmanship at the time of construction has led to poor sound insulation and noise flanking due to bridging the acoustic elements via incorrect fixings etc. and its damaged the original components.
  • A change in material of wall or floor finishes (e.g. carpet to laminate flooring), has increased the level of noise transmitted to the dwelling below – this is one of the most common reasons and increase in noise.
  • Changes have been made to the existing construction which has had a negative impact on the sound insulation
  • The original existing construction was never suitable to meet the insulation standards required of a separating wall or floor structure – in-line with Part E of Building Regulations.
  • The existing wall or floor components have deteriorated over time and are in need of replacement this may be because the wrong fixings have been used on the existing floors.
  • The upgrading of the existing windows to double and/or triple glazing has reduced external or background noise through the building façade, thus making neighbour noise more noticeable through separating walls and floors.
  • New cut outs in the existing wall to hide new cable for the wall mounted LCD TV’s is another popular reason for noise bridging through walls.

Other factors may have an impact on the overall noise levels, such as when new neighbours move in. Occupants may be more aware of sound insulation issues due to different living patterns between neighbours.

Upgrades or changes to the buildings structure, i.e. previous service works for water pipes, drainage and heating systems may have removed acoustic materials or interfered with acoustic isolation. This can lead to a wide disparity in performance between damaged and undamaged floors or walls.

In our experience, one of the most common triggers for noise complaints is the change of a room surface e.g. from carpet to wooden laminate flooring or floor tiles.  This can typically lead to a 10-20dB reduction in insulation performance. This can lead to neighbours below the apartment changing their assessment of impact noise from “acceptable” to “intolerable”. This can often lead to protracted and expensive legal issues especially if your lease doesn’t allow for hard surface upgrades.

Noise_Problems_Failed_Sound_Testing

People who live in detached houses or well-insulated attached houses may never have experienced hearing noise from neighbours, so when they move into a flat or attached dwelling they may feel that the level of sound insulation is poor, when infact it complies with Building Regulations Part E.

If you suspect that your noise levels are too high and you would like us to undertake sample sound insulation testing, or you would like us to investigate your noise complaints, please contact us now at: info@aptsountesting.co.uk  or phone us on 07775623464

Sound Testing In House Conversions

Sound Testing Results in House Conversions.

 Due to the housing shortage many houses are being converted into flats, which has resulted in a massive spike in noise complains amongst neighbours in such developments. Much of this rise in complaints are due to insufficient acoustic design at the start of the project, this means the dividing partitions are not being designed or constructed to comply with Part E of Building Regulations for Conversions.

 In our experience many of the sound insulation tests we undertake on refurbishment projects achieve 30-35dB for airborne sound, which is well below the required 43dB as stipulated in Part E. For impact sound testing, the figures are usually around 70dB which is well above the required 64dB, which is also a massive failure.

 Taking the above into account is it essential that the acoustic design is addressed right from the start of the refurbishment project.  The usual existing construction is 175mm joists with floorboards attached to the top and a single layer of plasterboard – as per the below detail:

Failed_sound_Testing_Due_to_existing_floor_Construction_

Upgrades or changes to the buildings structure, i.e. previous service works for water pipes, drainage and heating systems may have removed acoustic materials or interfered with acoustic isolation. This can lead to a wide disparity in performance between damaged and undamaged floors or walls.

 To overcome many of these issues we can visit site and undertake sample sound insulation testing through your property to establish the current noise levels. Once the noise levels have been established we can advise on acoustic upgrades to help you improve the sound insulation levels. it may be as simple as the installation of an acoustic resilient layer on the floor, or a minor wall upgrade.

Precompletion Sound Testing Throughout London

Precompletion Sound Testing Throughout London 

To help enforce good acoustic design principles pre-completion sound testing was introduced July 2003, this resulted in all new build properties and conversions which were built after this date are require 10% of each party wall/floor construction type to be tested. APT Sound Testing undertake precompletion sound testing throughout London.

Precompletion Sound Insulation Testing is carried out between pairs of rooms separated by party walls or floors. The two ‘habitable’ areas that usually require sound testing are living rooms and bedrooms, although other rooms can be tested if this is not possible, i.e. kitchen to bedroom. Here is a quick description of the tests:

sound testing

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.

Impact Sound Tests

For vertically separated rooms, an Impact sound testing 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.

Required Sound Test Levels

The Building Regulation Part E set minimum performance requirements for sound insulation requirements between spaces. To help you better understand the sound level requirements of Part E, 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

Whatever the problem APT Sound Testing can usually find an acoustic solution that will satisfy Part E of Building Regulations. If you have a project that’s needs acoustic design advice or needs sound insulation testing then please contact us at: info@aptsoundtesting.co.uk or phone us directly on 0203 669 2650 and we should be able to offer you an expedient acoustic solution to help you achieve practical completion.

 

Pathway To Successful Sound Testing

Pathway to Successful Sound Testing 

We have undertaken hundreds of sound throughout London and the South East and have managed to streamline our pathway to successful sound testing. We also offer robust and cost effective acoustic design advice to ensure your compliance with Part E of Regulations. Our usual pathway for successful sound testing is:

1. Our Acoustic Design Service

2. Acoustic Site Audits

3. Precompletion Sound Testing

 

Acoustic Design Service

On our experience some of the most common mistakes during the construction are as follows:

  • Using lightweight blocks in the inner envelope construction as sound will travel along light block-work both vertically and horizontally from dwelling to dwelling.
  • The use of resilient suspended ceilings will help improve the performance of the floor partition.
  • Not incorporating a high quality resilient acoustic membrane on top of the floor to improve the impact performance of a floor.
  • Ensuring all penetration’s are fully sealed where they terminate through floors and they are adequately boxed with acoustic quilt and two layers of plasterboard.

sound testing equipment 

Acoustic Site Audits

We can undertake acoustic site audits, to let us view the existing site construction. This allows us to check for potential problematic areas such as the inclusion of lightweight blocks within the existing wall construction. It also lets us check that the installation teams are installing the acoustic materials as per manufacturer’s guidelines, thus avoiding crucial onsite mistakes. In our experience a sound test failure is often due to the poor workmanship rather than the actual design. The site survey visits negate the risk of sound test failure.

We can also undertake 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 which takes into account the performance of the existing construction.

 

Defect Diagnosis & Remedial Advice

With many 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 the cost for acoustic design advice will be minimal. Sometimes, there are more technical issues which require more detailed diagnosis and invasive investigation, such as large amounts of noise flanking due to serious design faults, e.g. poor material isolation.

 

Precompletion Sound Testing

To help enforce good acoustic design principles pre-completion sound testing was introduced July 2003, this resulted in all new build properties and conversions which were built after this date are require 10% of each party wall/floor construction type to be tested.

Whatever the problem we can usually find an acoustic solution that will satisfy Part E of Building Regulations. If you have a project that’s needs acoustic design advice or needs sound insulation testing then please contact us at: info@aptsoundtesting.co.uk or phone us directly on 0203 669 2650 and we should be able to offer you an expedient acoustic solution to help you achieve practical completion.

 

Failed a Sound Test?

Failed a Sound Test?

If a client has failed a sound test, they often ask us for the reason why. It is almost certainly the result of a combination, of the following items:

  • Poor acoustic advice
  • Poor onsite installation
  • Flanking noise which comprises the sound insulating element.

Unfortunately, if you fail the sound testing its not easily rectified, as it usually means a major upgrade to the failed partition and thereafter another sound insulation test, which is both costly and time consuming.

If you do find yourself in this unfortunate situation, the first thing to do is contact APT Sound Testing your ‘friendly acoustic consultant’. We will be able to advise you on how to undertake minor acoustic upgrades, once we have obtained a copy of the failed sound test report. We can then ascertain the potential weak acoustic elements from the graphical results, and advise on a robust acoustic solution to building regulations Part E.

We will also be happy to liaise with your architect to ensure that all areas have been covered in the initial/remedial acoustic design. For a small fee we can visit site and undertake an ‘onsite design review’; or, do a an office based design review which cuts costs even further – to do this we would need all plans and sections relating to the project.

NoiseFlankingWall

Problems with airborne and structure borne sound are often associated with direct flanking transmissions through floors, supporting walls and other associated structures. You need 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 to suit.

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 noise flanking path. The most common such flanking path is the inner leaf of an external cavity wall.

If you have suffered a sound test failure and/or you require acoustic design advice then please email us in info@aptsoundtesting.co.ukor phone our design manager Darren on 07775623464. We have the experience, professionalism and acoustic know how to ensure that your project can achieve Part E of Building Regulations.

SOUND TESTING ON LONDON DEVELOPMENTS

 SOUND TESTING ON LONDON DEVELOPMENTS

London is a massive city containing over 8 million people. In this overcrowded environment it is essential that noise transference between adjoining properties in kept to a minimum for the occupant’s well being.

When there are problems with noise transference between dwellings, and the building’s design is called into question, we can offer advice on how to upgrade the wall and/or wall partition to improve the sound insulation values.

We have extensive knowledge regarding the way different materials and construction methods can influence the results of a sound test and subsequent noise transference, this helps to ensure your company achieves compliance with the Sound Testing for Part E of Building Regulations at pre completion stage.

Pre completion sound testing in London has been a mandatory requirement since July 2003. All new build properties and conversions which were built after this date require 10% of each party wall/floor construction type to be tested. Sound insulation testing is to be carried out between pairs of rooms separated by party walls and/or floors. In is usual to test between living rooms and bedrooms as these are classed as the two main habitable rooms; however, other rooms can be used if this is not possible such as study’s, kitchens and dining rooms.

Also, we are also experiencing a rise in the amount of sound testing that’s required to existing London buildings which isn’t surprising as the amounts of noise complaints to councils has doubled in the last 10 years, as a result we have carried out a large amount of sound tests in council/housing association blocks, where the residents are experiencing excess noise between the dividing wall and floor partitions.

We also undertake sound testing to existing flats where the lease stipulates that wooden floors should not be used instead of carpets and as a result of the change of floor finishes the noise levels have increased through the floors – especially the impact noise.  In all these instances we can undertake sound testing to highlight the existing noise levels so acoustic upgrades – if required) can be targeted and implemented, i.e. it may be as simple as installing an acoustic membrane on the floors below the timber floor.

sound testing equipment

The airborne sound testing is 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.

For vertically separated rooms, another type of sound test called Impact sound testing may also be required. This sound test is undertaken using a tapping machine 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 results (LnT,w) is calculated and compared to the requirements of Approved Document E of Building Regulations.

To help control noise issues APT Sound Testing can undertake UKAS accredited Part E sound testing in London and the South East. Our sound test engineers carry all the latest acoustic equipment. We provide full UKAS accredited sound insulation testing and air testing, so all or testing is completed to a strict quality controlled standard

If you would like advice on your acoustic design or sound testing in London, please contact us now at info@aptsoundtesting.co.uk or call us on 07775623464.

Sound Testing On Refurbishment Projects

Sound Testing On Refurbishment Projects

When it comes to refurbishment projects i.e. large houses that have been converted into flats and/or an office block into flats, we can undertake a sample sound test of the existing wall and floor construction to ascertain the existing sound insulation levels. Once we have established the sound levels for the existing construction, we can then look at extent of the acoustic upgrades to attain Part E Compliance. This is much more effective than just forwarding an acoustic design that may be to excessive and expensive, especially when the existing construction is already ‘acoustically’ robust and therefore only needs to improve by a a minimal amount such as 1-3dB. By having the existing sound levels of the partitions we can recommend targeted, acoustic upgrades to comply with Building Regulations Part E.

This Video show some of the sound leakage paths

The sound insulation levels required to pass Part E for refurbishment projects are less stringent than new build projects. Instead of 45dB for airborne its 43dB (2 dB less), and for instead of 62dB for Impact Sound Testing its 64dB on new build (2 dB more).

On refurbishment projects you cannot use Robust Details, therefore sound testing has to be undertaken. Obviously due to the complex nature of refurbishment projects its best if you consult with us at the beginning as we can offer advice on how to upgrade the partitions to pass the sound testing.   We can also help if your building fails the sound insulation testing by offering a targeted acoustic design solution saving time and potential costs.

If you have a project that requires sound insulation testing then contact us now, we can propose a sound testing schedule that should comply with Part E. Please contact us at: info@aptsoundtesting.co.uk or call us at 07775623464

Sound Insulation Testing In Compliance With Building Regulations Part E.

Sound Insulation Testing In Compliance With Building Regulations Part E.

Sound Testing is usually undertaken near the end of a project to show that the party wall and floors meet the Building Regulations. Approved Document E stipulated performance values.  The method for sound testing for airborne and impact sound insulation is in full accordance with: the suggested methods presented in BS EN ISO 140-parts 4 & 7: 1998.

Detached houses don’t require sound insulation testing, however if the house has been built on to the end of an existing house and/or terrace it usually requires 2 airborne wall tests – 1 through the lower kitchen/lounge and one through the bedroom walls on the upper floors.

Buildings such as apartment blocks often require airborne and impact sound insulations tests. Airborne sound insulation testing is normally required between horizontally and vertically separated pairs of rooms i.e. the wall and floor partitions. 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.

sound testing

Thereafter impact sound testing may also be required for vertically separated dwellings. Impact sound insulation testing is undertaken using a “tapping machine”, which drops a series of weights/small hammers 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

When it comes to refurbishment projects i.e. large houses converted into flats and/or an office block into flats we can undertake a sample sound test of the existing wall and floor construction. Once we have established the sound levels for the existing construction we can then look at extent of the acoustic upgrades to attain Part E Compliance. This is much more effective than just forwarding an acoustic design that may be to excessive and expensive, especially when the existing construction is already ‘acoustically’ robust and therefore only needs to improve by a 1-3dB.

The sound insulation levels required to pass Part E are usually 45dB for airborne wall and floors and 62dB for Impact Sound Testing on new build, however sometimes a higher target may be required in-line with the Code for Sustainable Homes; this is usually in defined in the following figures +3, 5 & 8dB, this means if its plus 5dB you will need to achieve 50dB for airborne and 57dB for impact sound testing.  Obviously if you need to comply with the Code for Sustainable Homes then special attention must be shown to the acoustic design from the offset to reduce the chance of sound testing failure.

APT Sound Testing can help you to achieve this more robust design criterion. We can also help if your building fails the sound insulation testing by offering a targeted acoustic design solution saving time and potential costs.

If you have a project that requires sound insulation testing then contact us now, we can propose a sound testing schedule that should comply with Part E. Please contact us at: info@aptsoundtesting.co.uk or call us at 07775623464

DESIGNING YOUR BUILDING TO PASS PART E SOUND INSULATION TESTING

Designing your Building to Pass Part E Sound  Insulation Testing

We at  APT Sound Testing often get asked what architectural features or plan arrangements can reduce the level of sound insulation or introduce additional sources that may cause us to fail our sound insulation testing.

Here is a quick list of the most common problems:

  • Internal stairs directly beside a separating wall – this can lead to footsteps being heard inside the adjacent dwelling, especially in bedrooms.
  • Using lightweight blocks on flats – lightweight blocks are often used in the construction of internal walls despite the block manufacturer’s warnings that they should not be used for the inner envelope or dividing wall construction. The walls are so lightweight they vibrate (almost like a snare drum) so sound can travel up or across the partition.
  • Chimney stacks, flues and fireplaces built within a separating wall – this can lead to sound traveling up the flue and being heard in flats above and/or below.
  • Recessed cupboards (presses) within a separating wall – this usually means that the width of the sound insulation is compromised which directly leads to a reduction in sound insulation levels.  
  • A flat spanning over several flats below, for instance a penthouse;
  • Communal stairs beside a separating wall – as this is a heavy trafficked area it can lead to footsteps being heard inside the adjacent dwelling, especially in bedrooms.
  • Communal vertical soil vent pipes and horizontal service pipes within a separating floor – if the services are not properly boxed out this can lead to general noise going straight through the floor as well as the noise of flushing water as it runs down the SVP pipes etc.
  • Lifts beside separating walls – this is often a bad scenario due to the higher start up current that’s needed to start a lift, this can cause a loud whine when the lift first starts and if there is insufficient sound insulation within the lift wall this will usually be heard by the adjacent resident/s
  • Water pumps used to raise water pressure – this can be problematic especially where a bedroom is located on the opposite side of the partition.
  • Chimney stacks, flues and fireplaces built within a separating wall – this is often a major cause of noise problems as they are often built quite close to each other thus reducing the mass of the separating wall/partition.  
  • Recessed cupboards (presses) within a separating wall – again this reduces the sound insulation levels as it reduces the mass of the wall partition.

It is worth noting that with careful consideration during the design phase most potential sound transference problems can be negated.

ACOUSTIC_DESIGN

Unfortunately, general exposure to excess amounts of noise from adjacent dwellings may act as a catalyst affecting the occupant’s health and well-being.  Noise that is unavoidable, unimportant or emotive is often the most annoying. Disrupted sleep and listening to television/radio are the most common noise-disrupted activities. Noise transmission between dwellings causes increased tension between neighbours and leads to disputes, which may result in physical assaults.

If you are unsure of your buildings acoustic design and/or you require sound testing contact APT Sound Testing at: info@aptsoundtesting.co.uk or call us on 07775623464