Acoustic Terminology F – L

Acoustic Terminology F – L 

Our previous blog explained the C-F of acoustic terminology, this blog further covers F – L.

Following on from our previous blogs which gave a brief description of

Flanking strip or edge strip

This is a resilient strip using foamed polyethylene normally 5 mm thick, which is located at the perimeter of a floor to isolate the floor boards from the walls and skirtings.

Flanking transmission

This is airborne or impact transmission between rooms that is transmitted via flanking elements and/or flanking elements in conjunction with the main separating elements. An example of a flanking element is the inner leaf of an external wall that connects to the separating ‘core’ of a wall or floor.

Flexible closer

This is a flexible cavity stop or cavity barrier which seals the air path in cavities linking adjoining dwellings.

Floating floor treatment (FFT)

This is a timber floating floor system which may use battens, cradles or platform base, all of which use a resilient layer to provide isolation from the base floor and adjacent wall elements.

Gypsum based plasterboard

This is a dry lining board applied to walls, ceilings and within floating floor treatments which has gypsum content. It may also have fibre reinforcement within the board.

Impact sound

This is sound which is propagated from a noise source through a direct

medium. An example of this is footfall on a floor.

Impact sound transmission

This is sound which is spread from an impact noise source in direct contact with a building element.

Isolation

This is a strategy to limit the number and type of rigid connections between elements of construction.

 L’nT,w

This is the weighted standardized impact sound pressure level. A single-number quantity (weighted) to characterise the impact sound insulation of floors, in accordance with BS EN ISO 717-2: 1997.

If you have a project that requires our acoustic design service and/or sound insulation testing please contact us at info@aptsoundtesting.co.uk or youhone Darren Direct on 07775623464. You can also visit our website at: www.aptsoundtesting.co.uk

 

Acoustic Terminology A-B

Acoustic Terminology A-B

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

 Absorption

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

Absorbent Material

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

Airborne sound

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

Airborne Sound Transmission

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

Air Path

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

 Bonded resilient cover

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

Acoustic_Site_Survey

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

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

Good Acoustic Design Considerations

Good Acoustic Design Considerations

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

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

sound testing equipment

Here are some simple acoustic design tips:

  • Ensure all penetrations are fully sealed where they terminate through floors and they are adequately boxed with acoustic quilt and two layers of plasterboard.
  • Use resilient acoustic hangers within the ceiling design to provide isolation between materials.
  • Avoid the use of lightweight blocks in the inner envelope construction as sound will travel both vertically and horizontally from dwelling to dwelling.
  • Ensure all support steels/timbers are carefully boxed out where they travel from flat to flat vertically and horizontally.
  • Use a high quality resilient acoustic membrane on top of the floor to improve the impact performance of a floor.

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

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

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

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

Acoustic Design Service for London Projects

Acoustic Design Service for London Projects

We have a vast amount of experience in dealing with acoustic partitions on large and small scale construction developments. using this experience we offer easy to follow acoustic design reports which helps provide our clients with a helpful easy to follow turnkey solution for their acoustic requirements. We can usually provide considerable cost and efficiency benefits for all our clients’ new build and conversion projects.

architect drafting a house blueprint

architect drafting a house blueprint

In our experience by simply constructing a robust separating wall or floor this may not in itself provide sufficient sound insulation to pass Building Regulations Part E, as the junctions of each separating wall and/or floor with other parts of the building are equally as important and require careful consideration to prevent noise flanking etc.  Flanking noise transmission can occur via construction components such as:

The most common noise flanking pathways are as follows:

  • Dividing Floor Partitions – Through Floor and Floor Joist Space (if insulation has not been installed or direct fixing to joists without a drop ceiling below the partition under test)
  • Dividing Ceiling Partitions – Above and Through the Ceiling Space (where an adequate acoustic break has not been carried on through the ceiling void)
  • Shared Structural Building Components – Floor Boards, Floor Joists, Continuous Drywall Partitions, Continuous Concrete Floors, and Cement Block Walls.
  • Through Structural Steel (structural steel beams are often a major cause of noise transmission as plasterboard is often fixed directly to the steel without sound breaks)
  • Plumbing Chases – Junctures Between the Walls & Floor Slab Above or at the Exterior Wall Juncture (this should be filed with mortar etc. to add mass to this weakened area)
  • Through Windows (if they are no double glazed or have secondary glazing as a minimum)
  • Fixtures & Outlets – Light Switches, Telephone Outlets, and Recessed Lighting Fixtures (if penetrations have been cut back to back with the opposite dwelling under test)
  • Structural Joints – Perimeter Joints at Wall & Floor, Through Wall & Ceiling Junctures (these should be filled with acoustic mastic)
  • Around the End of the Partition Through the Adjacent Wall (acoustic mastic should be used to seal this junction)

The overall acoustic design and construction should therefore be considered from the offset and not just the separating wall or floor partitions.  Flanking sound transmission through lightweight existing inner walls may be the dominant pathway between adjoining dwellings, when converting existing buildings in to residential dwellings such as offices conversions.

We are UKAS accredited to undertake sound insulation testing of which is done ‘in-house’ which allows us to offer a comprehensive, seamless service from initial design development, without using any outside contractors.

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

Good Acoustic Design Detailing

Good Acoustic Design Detailing.

Careful consideration to acoustic design detailing should be used from the offset of the project, whether it’s a new build or conversion project, 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.

architect drafting a house blueprint

To help our clients achieve a successful sound test at the first attempt, we offer a full acoustic package which consists of the following elements:

  • 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.
  • 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.
  • Acoustic Design Review – a full design review of the proposed developments party walls and floors.

There are many design considerations that need to be accounted for when allowing for your project/s, they are:

  • Avoid the use of lightweight blocks in the inner envelope construction as sound will travel both vertically and horizontally from dwelling to dwelling.
  • The use of resilient suspended ceilings will help improve the performance of the floor partition.
  • Ensure all support steels/timbers are carefully boxed out where they travel from flat to flat vertically and horizontally.
  • Use a high quality resilient acoustic membrane on top of the floor to improve the impact performance of a floor.
  • Ensure all penetrations are fully sealed where they terminate through floors and they are adequately boxed with acoustic quilt and two layers of plasterboard.

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

How Is Sound Insulation Testing Carried Out?

How Is Sound Insulation Testing Carried Out?

For airborne wall and floor sound tests, two individual speaker positions are used for each source room; with a total of ten individual 1/3 octave band measurements recorded for both the source and receiver rooms. Measurements are then made to monitor the levels in the receiving room of the tested partition in question. This gives a basic level difference between source and receiver rooms.

Sound_Insulation_Testing_Equipment

This basic level difference is then ‘corrected’ to allow for the reverberation time (the time taken, in seconds, for a noise source to decay by 60 dB) and the existing levels of background noise monitored whilst in the receiving room.

All our tests are carried out in full accordance with BS EN ISO 140-1998 parts 4 (airborne sound testing) and 7 (impact sound testing), and the calculation of all single figure results are done so in accordance with BS EN ISO 717:1.

How do I know when my site is ready for testing?

Sound testing is typically conducted when a development nears completion, and once all internal and external doors and windows have been fitted, it is worth noting that no carpets should be installed prior to the sound testing.

To be able to conduct sound insulation testing we a constant supply of 240V power; we cannot use generator power. We also require a quiet site (a noisy site can make conducting the tests extremely difficult), so no drilling, jack hammers etc. should be used whilst the testing is taking place. We also require full access to all rooms to either side of the dividing partition so if it is a requirement to access a neighbour’s property, this must be arranged prior to the test date.

If you require a sound insulation test than contact us know, we will explain what the test entails and send you our informative checklist to help you prepare for the test. It is our mission to ensure our clients pass their testing at the first attempt. We pride ourselves on providing a ‘one stop acoustic solution’ for all your acoustic requirements.

If you would like more information in regards to our acoustic services, including acoustic design reviews, sound testing and noise surveys please contact us at: info@aptsoundtesting.co.uk or call Darren on 07775623464 or visit our website at: www.aptsoundtesting.co.uk

 

 

 

Approved Document E: Frequently Asked Questions

Approved Document E: Frequently Asked Questions

Why am I required to undertake sound insulation testing?  

Sound insulation and speech privacy are critical for a variety of reasons. Inadequate sound insulation can be extremely distressing to those affected by it and may lead no major noise disputes and legal actions. For example, in an apartment block, your upstairs neighbour may like playing loud music. However, the downstairs occupant may be working nights and sleeping throughout the day, thus any inadequate sound insulation between these two flats would cause great disturbance and distress to the downstairs occupants.

Noise_Problems_Failed_Sound_Testing

 What is precompletion sound insulation testing?

Precompletion sound testing is a building regulation requirement for all new build and dwellings formed by ‘material change of use”, i.e. conversion projects. It has been a requirement that you undertake sound testing on dwellings since 2003. Sound testing should be undertaken to 10% of properties in each development to ensure that the separating walls & floors between habitable rooms of neighbouring properties meet the minimum requirements as defined by Approved Document E, commonly referred to as Approved Document E; for instance:

  • For a pair of semi-detached Houses – a set of tests would usually comprise two airborne sound insulation tests of a separating wall.
  • For Flats (up to 10 units) – a six pack would normally be required, this comprises of: two airborne wall tests, two airborne floor tests and two impact floor sound tests. The easiest way to work out the number of tests required is to multiply 1 x 6 packs for every 10 flats, i.e. if you have 22 flats you will require 3 x 6 packs which equals 18 sound tests in total.
  • For Rooms for Residential Purposes (up to 10 rooms) (student accommodation, hotel rooms, care homes etc.) – a set of tests would usually comprise: one airborne sound insulation tests of a separating wall; one airborne sound insulation test of a separating floor; one impact sound transmission test of a separating floor.

Sound_Testing_Flats

If you would like more information on our full range of our acoustic services, including sound testing, acoustic design and noise surveys, please contact us now at info@aptsoundtesting.co.uk or call Darren direct on 07775 623464.

Noise Flanking Paths

Noise Flanking Paths

To reduce the chance of sound testing failure, it is imperative that flanking transmission is considered at the design stage to reduce potential noise flanking paths. Good detailing at the design stage will minimise this effect and optimise the overall levels of acoustic privacy achieved. If designing for residential units, design advice on flanking details must be followed to maximise the possibility of achieving the specified acoustic performance. It is imperative that the design advice is followed, otherwise the site sound insulation values may not meet the performance criteria required and subsequent expensive remedial treatment may be required.

sound_transmission_through_floors

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. One of the easiest ways of dealing with sound flanking issues is to use isolation strips around the perimeter of the partitions at the edges of floors and walls, this should be finished with acoustic sealant

One of the main reasons for flanking sound test failures is when the inner leaf of the perimeter wall is built with light weight blocks. This acts like a large snare drum and the sound simple travels straight up the wall from one flat to the flat above and/or below. Even if you have used a acoustically robust wall and/or floor partition the sound insulation testing may still fail. If you have used lightweight blocks in your onsite construction and the building fails the sound test you may need to construction independent internal plasterboard lining throughout the inner perimeter wall, this should isolate the lightweight blocks and ensure the flanking path is minimized.

If the onsite construction has gaps, cracks or holes it will conduct airborne sounds and can significantly reduce the sound insulation of a construction. For optimum sound insulation a construction must be airtight. Most small gaps can be sealed at the finishing stage using Gyproc jointing compounds. Small gaps or air paths around perimeter Gypframe framework can be sealed with sealant. At the base of the partition, gaps will occur which can be filled with acoustic mastic.

If you would like more information in regards to sound insulation testing and or acoustic design advice, then please call us now at info@airpressuretesting.net or call me (Darren) direct on 07775623464.

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 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.