Month: January 2020

What is a Floor Plenum Test?

What is a Floor Plenum Test?

What is a Floor Plenum Test?
A floor plenum is a void between a building’s floor structure and a raised access floor. The floor plenum is used for distributing conditioned air to the spaces above.

It is important that conditioned air in a floor plenum flows into the occupied zone and does not leak into cavities, risers, stairwells, heating trenches or other adjacent zones. A properly sealed floor plenum will allow the floor grills and diffusers to fulfil their primary role of delivering air at the correct flow rate. As a result, the airtightness of floor plenums (or lack of) can be a serious energy efficiency issue and is essential for the whole air conditioning system to work.

What is a Floor Plenum Test?

Testing procedure BG65 / 2016, addresses these issues and places upper limits on the air leakage of floor plenums. Distinctions are made between air leakage to adjacent spaces – normally referred to as plenum leakage, and uncontrolled air leakage into conditioned zones – normally referred to as raised access floor leakage.

How is a floor plenum test carried out?

In brief, we remove a box a temporary a tile is removed from the plenum and our fan housing is installed directly above the opening. A fan is then installed into the box and this is all sealed against the floor. Any air handling ducts serving the test zone need to be turned off, isolated and temporarily sealed, stopping the passage of air to outside of the test zone via duct-work. Thereafter another tile is removed and a mock floor tile with a drill hole for the high pressure tube is installed in its place. After the equipment is set up a series of tests is undertake and the readings recorded and then checked against the floor plenum air tightness specification.

What is a Floor Plenum Test?

If the plenum test fails, you’re APT plenum test engineer will carry out a smoke test to look for air leakage paths. If you have floor or ceiling plenums in your building you need to be aware that a staggering 70-80% fail their first air tightness test. APT Sound Testing has years of experience of raised access floor plenum testing and can work with you to ensure you pass your floor plenum air test at the first attempt.

We can ensure that an onsite air test site audit is arranged as soon as the floor is in place; we can then undertake an initial floor plenum air test and smoke survey to check the air leakage result and check for air leakage paths within the plenum envelope. Once we have assessed the air leakage paths we can then supply a smoke survey report for your sealing contractors to use as reference to ensure your plenums are adequately sealed.

The most common air leakage paths within floor plenum construction

In order to create an effective airtight floor plenum and achieve a successful floor plenum air test, all mechanical and electrical penetrations and perimeter joints must be properly sealed. An evaluation of the following areas/components that can typically create Inefficiencies should be undertaken during the early design phases:

  1. All service penetrations through the access floor, walls and subfloor including:
  2. Cable bundles and cable trays
  3. Pipes
  4. Fire/plenum barriers
  5. Cable trunking – must be internally sealed within the void
  6. Masonry work – incomplete or poorly jointed masonry walls will result in greater air leakage. All masonry joints must be filled and masonry paint applied as a finish.
  7. Risers need to be properly sealed throughout all plenums/ducting need to be sealed.
  8. Plasterboard on studs at board edges and the ends below the raised floor level need to be sealed.
  9. Gaps between compartment barriers, top of raised access floor and sub floor respectively need to be sealed.
  10. Gaps between any curtain walling/glazing need to be sealed.

What happens if I fail my Floor Plenum Test?

A large number of floor plenums (70-80%) fail the initial air tightness test so don’t panic!

If we undertake the floor plenum test and it fails UKAS accredited test engineers will undertake a targeted smoke survey to highlight the main air leakage paths. We will then issue a detailed smoke survey report for your contactors to reference during the remedial sealing works. This will help us the remedial sealing works at they can quickly target the main air leakage paths within the floor plenum construction. We can also undertake thermal imaging surveys to pinpoint the main air leakage paths on the day of the plenum testing.

We also allow for the option of visiting site during the sealing works to ensure your contractors are adequately sealing the plenum prior to the second air tightness test. If you would like more information in regards to the most common air leakage paths visit our Plenum Testing page or call us on 01525 303905. Supporting document BG65 / 2016 also contains lots of information on how to design, constructing and test floor plenums.

Alternatively, for more information on all our services please visit our website at:  

Sound Insulation Testing in London

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 wellbeing. 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.

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.

Sound Insulation Testing in London

Plate A – Tapping Machine for 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.

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

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.

Unwanted noise travelling along flanking paths will make the building structure vibrate which causes the sound to radiate into your room. One simple cost effective solution is to build another wall or ceiling in front of the original, but not connected to it (often called an independent wall or ceiling) so it provides isolation between materials.

One way to reduce the chance of flanking transmission is through careful consideration to the 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.

Sound Insulation Testing in London
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 you require pre-completion sound testing and/or you would like acoustic design advice on your project, please contact us now at

Four Steps to Successful Sound Testing

Four Steps to Successful Sound Testing

Four Steps to Successful Sound Testing

New homes are built to high standards; however, acoustics and noise control are important factors requiring careful consideration during design and specification, as well as pre-completion commissioning testing. Why choose APT Sound Testing? We provide full turnkey solution to help our clients achieve Building Regulations Part E compliance. We provide a professional acoustic consultancy service to help developers tackle the key issues. We have carried out thousands of sound insulation tests since 2006 so we have a large amount of experience in regards to Building Regulations Part E compliance.

Our Four Stages Areas of expertise of tackling sound are:

  1. Acoustic Design

During early design and construction process, we visit site to conduct a comprehensive acoustic design survey and review, we also take this opportunity to meet; where possible, the site/project manager, architects etc. The first stage of the acoustic design is to send through the design drawings – to include sections etc. so APT Sound Testing can 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.

APT Sound Testing 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:

  • There are no flanking points, where isolated partitions are wrongly mechanically fixed together to caused noise bridging.
  • The walls and floors design are acoustically robust, to comply with Building Regulations Part E.
  • 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.
  • Acoustic floor treatments are compatible with the proposed floor finishes i.e. Carpets, Laminates, Floor Tiles and under floor heating systems.
  • Ongoing Site Construction

We provide the site team with 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.

Sound Testing for Part E of Building Regulations has been a mandatory requirement since July 2003. All new build dwellings and conversions which were built after this date require 10% of each party wall/floor construction type to be tested. Sound testing needs to be carried out between pairs of rooms separated by party walls and/or floors. In most cases the rooms to be sound tested will be the two main habitable rooms, i.e.  living rooms and bedrooms. The sound test procedure involves setting up a noise source in a room on one side of the party wall or floor and measuring the noise on both sides of the partition.

Different Types of Sound Testing

There are two types of sound insulation testing – airborne and impact. Airborne 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. The background levels in the receiver room are measured and the reverberation time in the receiver room is also measured.

For vertically separated rooms, an Impact sound test may also be required. Impact testing 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.

All APT’s test engineers carry the latest Norsonic equipment, which are class one rating all of our acoustic testing/sound testing is completed to a strict quality controlled standard. We provide full ISO & UKAS complaint sound testing.

  • Post Occupancy Sound Testing and Advice

We have carried out sound insulation testing and investigative/diagnostic work can help identify problems, especially if the specific properties of concern were not tested as part of a programme of precompletion testing. We also carry out sound testing and offer acoustic design advice where clients may have not followed the rules of their buildings lease agreements and installed timber floor etc. instead of the usually specified carpet finishes.

If you would like more information in regards to our acoustic design and/or sound insulation testing, please contact us at:  or visit our website at: Alternatively you can call Darren on 07775623464. 

Sound Testing Explained

Sound Testing Explained

Sound Testing Explained

Airborne and Impact Sound is transmitted through most walls and floors by setting the entire structure into vibration. This vibration generates new sound waves of reduced intensity on the other side. The passage of sound into one room of a building from a source located in another room or outside the building is termed ”sound transmission”. 

Sound transmission loss or Sound Reduction Index, R dB, is a measure of the effectiveness of a wall, floor, door or other barrier in restricting the passage of sound. The sound transmission loss varies with frequency and the loss is usually greater at higher frequencies. The unit of measure of sound transmission loss is the decibel (dB). The higher the transmission loss of a wall, the better it functions as a barrier to the passage of unwanted noise across the dividing (acoustic) partitions.

Approved Document E stipulates that there are two types of sound insulation in buildings: airborne and impact. Airborne sound insulation is used when sound produced directly into the air is insulated and it is determined by using the sound reduction index. Impact sound insulation is used for floating floors and it is determined by the sound pressure level in the adjacent room below.

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 shown for the appropriate dwelling in the table, for airborne testing in new builds properties a figure of 45dB or greater is required and for Impact testing 62dB and below. For conversion properties a figure of 43dB or greater is required and for Impact testing 64dB and below.

What is DnT,w

DnT,w is an in-situ measured performance parameter which demonstrates the level of resistance to sound transmission between two adjacent spaces, such as flats or houses. 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 – this should always be accounted for in the initial acoustic design.

What is Ctr

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

What is L’nT,w

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.

Weighted Sound Reduction Index Rw

When specifying the acoustic performance of an acoustic partition in a more general manner, it can be useful to describe the sound insulation by a single number. The weighted sound reduction index, Rw , is a rating method given in EN ISO 717-1. This standard fits a standard reference curve to the measured sound reduction index curve.

Within the EN ISO 717-1 standard, a rating method is also given where the Rw value is completed by two C-terms which are applied to two models of the noise spectra for various types of noise. These two terms, Rw + C and Rw + Ctr, also include the frequency range 100 – 3150 Hz but can be extended to 50 – 5000 Hz. As industrial and traffic noise often have high sound levels which are also below 100 Hz, it is recommended that the extended frequency area is used.

The summary value, Rw + C, gives the reduction value in dBA for a spectrum with a level which is equally high in all third-octave bands. This can be used for:

•             Highway road traffic travelling at speeds in excess of 80 km/h

•             Factories emitting mainly medium and high frequency noise

•             Living activities (talking, music, radio, TV)

•             Railway traffic at medium and high speed

•             Jet aircraft at a short distance

The summary value Rw + Ctr also gives the reduction value in dBA, spectrum with low-frequency dominance such as:

•             Disco music

•             Urban road traffic

•             Railway traffic at low speeds

•             Factories emitting mainly low and medium frequency noise

Both the impact and airborne insulation performance of floors and walls should be carefully considered from the start of the project to ensure that the minimum performance requirements for new and converted developments are met inline with Approved Document E

If you would like more information in regards to our sound testing and/or noise survey services, please contact us now by calling 01525 303905 or by visiting the APT Sound Testing Website today.