Approved Doc E - What do the numbers mean?

A sound insulation test of a separating partition will be considered as a pass if the airborne sound insulation is equal to or greater than the DnT,w + Ctr value required for the appropriate dwelling and if the impact sound insulation is equal to or less than the L’nT,w value for the appropriate dwelling. The performance criteria are different for new builds and conversions and also differences may occur due to the use of the dwelling type. 
   
DnT,w is an in-situ measured performance parameter which demonstrates the level of resistance to sound transmission between two adjacent spaces. The measurement will include both direct sound transmission and flanking sound transmission of the construction. Flanking transmission is the effect of sound travelling through the building and may be particularly evident where beams and joists bridge a common partition or along poorly isolated lightweight wall constructions. The DnT,w of a separating wall or floor will typically be of the order 5 to 7 dB lower than the manufacturers specified Rw (single figure quantity of sound insulation) for the single element, due principally to the contribution from flanking sound transmission around the element when it is built on site.

Ctr is the spectrum adaption term. It is a correction attributed to the sound insulation quantity to account for urban traffic noise.

L’nT,w is an in-situ measured performance parameter which demonstrates the level of resistance to impact sound transmission between floors. The impact measurement includes both direct sound transmission and flanking sound transmission.

Further information can be obtained by contacting Soundguard Acoustics or by downloading our FREE developers guide to Approved Doc E sound insulation testing

Approved Doc E Sound Testing - What's involved?

Airborne sound insulation test (walls & floors):  A controlled noise is generated by an amplifier and loudspeaker across a broad range of frequencies. The generated noise is very loud and can be in excess of 100dB. Initial measurements are taken using a 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.

Background noise measurements are made using a 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 characteristics and absorptiveness 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.

Impact sound transmission test (floors only):  This test is different, a calibrated ‘tapping machine’ which comprises of five 'hammers' driven up and down by a cam and electric motor is used to "tap" the floor surface by applying a known force on the floor structure. The machine is placed in several pre-determined positions. The resulting noise is measured in the dwelling below, using a sound level meter.

Background noise measurements are made using a 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 characteristics and absorptiveness of the room.

The measured noise levels in the receiving room (for impact floors tests), corrected for background and reverberation characteristics determines the impact sound insulation performance of the floor. For the impact noise the lower the measured level, the better the performance as less sound is being transmitted into the dwelling below.

Find out more about Sound Testing or contact Soundguard Acoustics

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Approved Doc E Sound Testing

Approved Document E – ‘Resistance to the passage of sound’ came into force on July 1st 2003 and provides minimum sound insulation Building Regulation requirement for newly built and converted residential dwellings as well as the Code for Sustainable Homes. Properties include houses, flats, student residences, care homes, hotels and schools.
Approved Document E of the Building Regulations is a government-issued document providing guidance for architects, developers, building control bodies, building services engineers, and others involved in the design and conversion of buildings for residential purpose. The document explains the sound testing requirement and provides advice and details about building procedures and materials that affect test results.
Devon based, Soundguard Acoustics Ltd is approved under the Association of Noise Consultants (ANC) registration scheme for carrying out sound insulation testing (Registration number: 194-01) and will carry out sound tests across the South West and the UK.
The ANC scheme is supported by Approved Document E and ensures that sound insulation tests are carried out by suitably qualified and experienced staff, in accordance with the appropriate standards.
The scheme ensures that sound tests are properly traceable, audited and that you receive a fully documented report and certificate which will be easily recognised for approval by your local Building Control department.
If you require further advice with your project or end of build sound testing then please contact us.

Is my build ready for a Sound Test?

Sound insulation tests are undertaken when the development is “pre-completed”. This means that the test rooms should be at a stage where just final finishing, such as painting and carpets are required. 

Soundguard Acoustics has provided a site checklist below to assist you with this. By ensuring that you meet the requirements of the checklist then the build can be deemed to be at a stage ready for soundinsulation testing. Where items are not in place this will negatively affect the sound insulation performance of the build.

  

• Windows should be fully installed, glazed & closable
• Trickle vents and other ventilation systems should be fitted
• Internal & external doors must be hung, glazed & closable 
• All wall, floors & ceiling constructions must be completed
• Skirting boards should all be fitted & cornice where fitted
• Electrical sockets, TV Aerial sockets & light switches should be fitted
• Rooms must be clear of building materials, tools & unfurnished
• No cosmetic floor coverings should be fitted (i.e. laminate, carpet, vinyl, ceramics)
• No trades should be working in the dwellings during the tests
• Access to rooms either side of the separating structure is essential
• Non-tester access to the rooms is prohibited during testing
• No noisy operations (drilling, cutting or groundwork) to occur nearby during testing
• Provision of 240v 50Hz mains power is required within the dwellings

How do I pass a Sound Test?

Performance in builds varies for many reasons. Assuming correct designs and material selection, the most common factor influencing performance is poor workmanship. Detailing is critical to maximising on site performance, especially in floor isolation and appropriate party wall construction.

Soundguard Acoustics recommend that you appoint our expert acoustic consultants at the start of your project to review the designs, and then also to carry out on site inspections during the build process to check specifically for any workmanship issues that could cause problems when it comes to sound testing. Soundguard Acoustics can provide routine review of basic plans to complex computer modelled partition designs to predict the completed performance.

 If you would like Soundguard Acoustics to review your designs and proposals or to comment on their suitability, then please speak to us about our acoustic design advice service. This is a relatively inexpensive option that can avoid sound testing failures which result in expensive remedial treatment and delay in your project.

What do I do if the test fails?

In line with the regulations you are required to carry out remedial works to ensure the development meets the relevant performance requirements and re-test. If you don't know what to do by way of remedial works then Soundguard Acoustics can advise you. You may also be asked by Building Control to test further examples of the construction elsewhere on the development in order to restore confidence and/or highlight the extent of the problem.

Soundguard is now Sound Testing the Southwest

Soundguard Acoustics Ltd is please to announce the we are now members of the Association of Noise Consultants (ANC) and registered with the pre-completion sound testing scheme. Soundguard Acoustics are now approved Document E ADE accredited sound testers and will be undertaking sound testing in the Southwest and south wales regions as well as bigger projects across the UK.