Sound Testing Rating Methods

Sound Testing Rating Methods

Sound tests are broken down into various sound testing rating methods. The sound insulation definition and terms are as follows:

Rating Method – RW

This single figure rating method is the rating used for laboratory airborne sound insulation tests. The figure indicates the amount of sound energy being stopped by a separating building element when tested in isolation in the absence of any flanking paths.

Acoustic_Design_Service

Rating Method – DnTw

The single figure rating method that gives the airborne sound insulation performance between two adjacent rooms within a building as measured within site conditions. The result achieved is affected not only by the separating element also by the surrounding structure and junction details.

Rating Method – Ctr

The Ctr adaptation term is a correction that can be added to either the RW (laboratory) or DnTw (site) airborne rating. The Ctr term is used because it targets the low frequency performance of a building element and in particular the performance achieved in the 100 – 315 Hz frequency range. This term was originally developed to describe how a building element would perform if subject to excessive low frequency sound sources, such as traffic and railway noise. This rating is expressed as RW + Ctr and allows the acoustic designer to critically compare performances. The rating method has not been universally welcomed. Some acoustician believe that the method is too crude as it only considers the low frequency performance, and because site measurements at low frequencies are prone to difficulties, which can lead to a lack of confidence in the results achieved.

Rating Method – Lnw

This single figure rating method is the rating used for laboratory impact sound insulation tests on separating floors. The figure indicates the amount of sound energy being transmitted through the floor tested in isolation, in the absence of any flanking paths. With impact sound insulation, the lower the figure the better the performance.

Rating Method – LnTw

The single figure rating method that is used for impact sound insulation tests for floors. The figure indicates the sound insulation performance between two adjacent rooms within a building as measured on site. The result achieved is affected not only by the separating floor but also by the surrounding structure, e.g. flanking walls and associated junction details.

Rating Method – Dncw

This is a single figure laboratory rating method, which is used for evaluating the airborne sound insulation performance of suspended ceilings. Laboratory tests simulate the room-to-room performance of the suspended ceiling when a partition is built up to the underside of the ceiling with sound transmitted via the plenum.

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

Sound Testing Definitions and Terms (1 of 2)

Sound Testing Definitions and Terms (1 of 2) 

Sound testing is usually undertaken near the end of a project to show that the party wall and floor partitions meet the standards shown in Building Regulations Approved Document E.  The method for 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. Sound tests are broken down into various rating methods. The sound insulation definition and terms are as follows:

What is Sound Insulation?

Sound is transmitted through most walls and floors by setting the entire structure into vibration. The higher the transmission loss of a wall, the better it functions as a barrier to the passage of unwanted noise. There are two types of sound insulation testing in buildings: airborne and impact.

Airborne Sound

This is sound caused by vibrations which transmit through a medium and reach the ear or some other form of detecting device. Sound is measured in loudness (decibels (dB)) and frequency (Hertz (Hz)). Airborne sound (or airborne noise) is sound that is transmitted through the air.

Noise_Problems_Failed_Sound_Testing

Impact sound

This is sound arising from the impact of an object on a building element – wall, floor, or ceiling. Typical sources are footsteps, jumping, and dropped objects. Impact sound transmission occurs because the impact causes both sides of the building element to vibrate, which generates sound waves.

Flanking Noise Transmission

Flanking is the transmission of sound from a source room to a receiving room by paths other than straight through the separating wall and/or floor partition. For example, impact sound may be transmitted from one room to another through a common timber floor. Other common mechanisms for flanking transmission include suspended ceilings, pipework, ducting, etc. Flanking sound is always present, except in the ‘ideal’ acoustics laboratory. In practice the sound insulation is often limited by the flanking transmission.

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

 

Sound Test Procedure

Sound Test Procedure 

The Sound Testing procedure is fairly simple and our engineer will be happy to explain this on site. Essentially, for party walls there is one type of sound insulation test which is airborne sound test and for compartment floors there are two types of sound insulation tests which are airborne and impact sound insulation tests. The airborne sound insulation test is carried out by means of a loudspeaker emitting a steady source of noise on one side of the partition (wall or floor) to be measured. The corresponding sound level is measured on the other side of the partition. Impact sound insulation tests are carried out by means of a tapping machine placed on the floor sample to be measured and the noise measured in the room or space below.

Sound_Insulation_Testing_Equipment

All our engineers carry out the sound test measurements in full accordance with the measurement procedures of BS EN ISO 140-4:1998[3] for field measurements with a single figure DnTw and LnTw in accordance with BS EN ISO 717.

Ongoing problems with airborne and structure borne sound are often associated with direct noise flanking transmission through floors and supporting walls and other associated structures. One common cause of noise flanking is often associated with the inclusion of lightweight blocks within the construction of the building envelope and/or blocked cavities. It all cases it is essential to establish if your problem is due to direct transmission, flanking transmission or a combination of both so that the most cost effective remedial treatment can be chosen.

We offer both pre-construction acoustic design advice and  we can also help if your building has failed the Part E sound test. We also offer onsite inspection services to ensure that the sound insulation elements are being installed as per manufactures guild-lines.

If your require sound insulation testing and/or you would like acoustic design advice on your project, please contact us now at info@aptsoundtesting.co.uk.

Sound Insulation Testing in London

Sound Insulation Testing in London

London is a massive city containing over 9 million people density and high rise apartments. With many living in this overcrowded environment it is essential that noise transference between adjoining properties in kept to a minimum for the occupant’s well-being. One way of ascertaining that a building is in compliance with Building Regulations Part E for the prevention of noise transference, is to undertake Sound Insulation Testing in London.

Sound_Testing_Flats

We have undertaken thousands of sound insulation tests throughout London and the South East on all types of projects from simple flat conversions to large developments containing hundreds of flats. We also undertake Sound Insulation Testing where a lease holder dispute has arisen, i.e. where the buildings lease stipulates that wooden floors should not be used instead of carpets and as a result of the change of floor finish the noise levels have increased – especially the impact noise. We can also undertake sample sound testing to highlight the existing noise levels so a targeted acoustic design can be undertaken.

Plate A – Tapping Machine for Impact Sound Testing

Impact Sound Testing

Currently we are also experiencing a rise in the amount of sound testing required to existing blocks of flats, such as existing council stock. This is hardly surprising as the amounts of noise complaints have more than doubled within the last 10 years due to residents experiencing excess noise between the dividing wall and floor partitions.  By utilising our extensive knowledge of different materials and construction we can forward a simple, explanative cost effective solution for wall and/or floor upgrade. Where our clients have followed our advice they have achieved a 100% success sound test pass rate ensuring compliance with Part E of Building Regulations.

APT Sound Insulation Testing offer both preconstruction and post construction design solutions if a project has failed the sound testing. We also offer onsite inspection services to ensure that the sound insulation elements are being installed as per manufactures guild-lines.

If your require pre-completion sound testing and/or you would like acoustic design advice on your project, please contact us now at info@aptsoundtesting.co.uk.

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 do my Floors Squeak?

Why do my Floors Squeak?

We often receive complaints from clients in regards to their floors creaking. This is often because the Joists are often spaced too far apart, which can result in a reduction in floor stiffness. Over-notching of joists can also lead to a reduction in floor stiffness and also potential squeaking. Although the floors may pass the airborne and impact sound testing, however it won’t stop the squeaking of the floors under the extra load imposed by people walking above.

sound_transmission_through_floors

Other problems may be down to the contractor using 12mm floor boarding instead of 18mm to the top of the joists, again this may allow the boards to move and squeak. It may also be down to the chipboard not sitting level across the joists, this may down to the  joists being installed at slightly the wrong level or a joist hanger may have been hit or come loose during the build. If the joist has been built into the wall the bearing could be unsatisfactory. it may be as simple as a missing joist, or cut edge unsupported or an over span on the joists.

  • Incorrect bridging of resilient layer by over-long screws/nails
  • Fixings connecting ceiling boards to resilient bars should not bridge to joists
  • Extra wide joist spacing that reduces floor stiffness
  • Platform floor resilient layers damaged by inserting pipes and services within the layers
  • Reduction in stiffness due to use of joist hangers
  • Ceiling boards not staggered
  • Over-notching of joists for services reduces floor stiffness
  • Incorrect omission of flanking strips at floor edge perimeters.

In most cases, due to the complexity of acoustical and noise problems along with an overwhelming variety of material designs and combinations due to varying constructions, it is impossible to cover all problems in a short article such as this; however in our experience if the acoustic design is taken into consideration from the offset of the project, then it usually results in compliance with Building Regulations Part E.

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

A Successful Sound Insulation Test

A Successful Sound Insulation Test

There are many considerations to achieving a successful sound test on your development. The main areas that need to be addressed are the dividing wall and floor construction.

When dealing with walls you normally just need to worry about airborne sound; however with walls it’s both airborne and impact sound which can be far more difficult to deal with.

sound_transmission_through_floors

The usual noise problems associated with airborne sound transmission is TV noise, music and speech. This can be dealt with by applying ceiling treatments as well as mass and isolation to the building components. Impact sound (footfall) performance is increased by the used of resilience layers and isolation of components to prevent noise flanking through the partition.

Airborne Sound Testing

For airborne sound insulation testing Building Regulation Part E requires you achieve at least 45dB for new build properties and 43dB for conversion developments, this applies both to party walls and floors between properties. This level is the difference between the source level and the receiver level during sound testing. Impact Sound TestingThe measurement is corrected for several factors such as background noise, room characteristics and frequency weighting, giving the final sound insulation performance value of the tested partition. In this case the higher the number the better the sound insulation performance. The measurement is done by using a Class 1 Analyser and the associated equipment.

Impact Sound Insulation Testing

For impact sound insulation testing Building Regulation Part E requires you achieve at least 62dB for new build properties and 64dB for conversion developments. Impact insulation performance only applies to party floors and related to the effectiveness of the floor construction in absorbing shock such as footfall noise.Sound_Insulation_Testing_Equipment

Good Acoustic Design

To try and ensure you meet the standards stipulated within Building Regulations Part E, careful consideration should be shown to the acoustic design detailing from the start of the project. Tackling the acoustic design for both new build and conversion project requires two different construction techniques and acoustic design detailing. With new build properties you have a blank canvas in terms of the overall design whereas with conversions you usually need to work with the existing’ onsite’ construction which can be quite difficult.

We offer an acoustic design package, which contains the following elements:

  1. 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.
  2. Acoustic Design Review – a full design review of the proposed developments party walls and floors.
  3. 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.
  4. Final Precompletion Sound Testing in compliance with Building Regulations Part E.

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

We have also started our new facebook page at: https://www.facebook.com/APT-Sound-Testing-1705040043131199/

Sound Testing to Comply with Lease Conditions

Sound Testing to Comply with Lease Conditions

Many people unknowingly fail to abide by the lease agreement as they may not know that there is usually a condition that states that they need to employ an acoustic company prior to making any changes to the floor of their apartment. The lease conditions often states that you need to undertake sound insulation testing prior to the commencement of works and upon completion of works.

In many cases their neighbour/s may complain that they can hear extra noise, this is often due to the fact that they may have changed the floor finish from carpet to wood. Unless extra acoustic design considerations are taken into account it usually results in an increase of extra airborne and impact noise being heard in unit below.

Sound_Testing_for_Lease_Agreements

Even if the floor assembly has been designed and constructed to provide adequate airborne isolation, impact noise can still be a major problem. If the finished floor surface had previously been carpet, the carpeting and underlay will normally provide a good degree of impact sound isolation. On the other hand, when the finished floor is floor is constructed in hardwood, stone or ceramic tile. Achieving good impact sound isolation requires much more attention.

If you think you may have a problem with sound in your dwelling and or you have encountered complaints from a neighbour due to modifications you have made to the floor partition then please contact us now. In all cases try be sure to describe the problem in as much detail as possible. Describe the nature of the sounds, when and where you or your neighbour can hear it. Is it impact noise or airborne noise or a combination of both? The more information you can provide us, the quicker we can try to determine the nature of the problem and subsequently find a solution.

In many cases, due to the complexity of acoustical and noise problems due to varying constructions, it is impossible to cover all problems in a short article such as this; however in our experience if we are employed from the beginning of a project, it usually results in compliance with Building Regulations Part E and /or compliance with your leasehold agreement, which may avert costly legal battles at the end of the project.

If you are about to make changes to your apartment, and you think you require acoustic design advice, then please contact us now at: info@aptsoundtesting.co.uk  or phone me directly 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.