Improving Air Tightness in Buildings
Darren Helliwell of APT Sound Testing looks at how construction companies can improve the air tightness of their buildings to ensure they pass their airtightness test first time.

With the Building Regulations and planning requirements and energy assessments pushing buildings towards ever-lower energy use it has become more important than ever to ensure your building is constructed as air tight as possible.

One of the most important steps to improve energy efficiency and occupiers wellbeing in both dwellings and the workplace is by reducing air leakage.

Detail showing a blower fan test equipment

Although the worst allowable air permeability stated in Building Regulations guidance has remained unchanged for some years at 10m3/hr/m2, the actual designed air leakage figure is much lower usually between 3 – 5m3/hr/m2; however, many construction companies are struggling to attain this lower air leakage figure.

If sufficient attention isn’t paid during the design and construction stages of a project, then the lower air leakage rate may be difficult to achieve and there is a much higher risk that the building will fail its airtightness test. Carrying out remediation sealing work and retesting when when a building fails can be a major headache, often leading to delays and cost over-runs.

In our experience, designing and constructing for Airtightness is not rocket science. While many things contribute to a building achieving its airtightness target, one of the biggest factors is usually down to the quality of on-site workmanship.

The key principles of achieving airtightness are as followings:

1. Having a simple air tightness design and construction strategy defined at design stage.
2. Drawings/details clearly identifying the location of the air-line from an early stage (the air-line is basically the elements that serve to provide an airtight envelope around the building).
3. Using building envelope components that are specified as airtight, such as windows, doors, curtain walling, roof lights etc.
4. Using common, easily repeatable details so reduce the chance of buildability issues.
5. Ensuring the building is correctly prepared in line with the air tightness checklists
6. Assigning a single individual to be the air tightness champion with overall responsibility for airtightness during the build and site preparation prior to the test.
7. Communicating the importance or airtightness throughout the entire project team and involving also trades that interface with one another.
8. Making it clear who is responsible for sealing in each instance and produce a sealing closing off sheet, so this process can be accurately monitored

In our experience air leakage commonly occurs at interfaces between construction elements, such as service penetrations and wall-to-roof junctions. Also, air leakage paths may be circuitous, meaning air may travel some distance through the building fabric between the points of entry and exit such as wall cavities etc.

The main areas of Air Leakage:

1. Seal all ducts and penetrations where the main services enter the building – we have encountered many tests where a water pipe duct has been left unsealed underneath kitchen units. After services have been installed in the duct, seal the rest of the duct.
2. Seal behind kitchen and utility room units at the wall/floor junction.
3. Seal all SVP and waste pipe penetrations passing through external walls and ceilings.
4. Make sure that the tops, sides & ends of all pipe/SVP boxing’s are sealed to prevent air leaking into the boxing, and escaping through SVP/waste pipe penetrations. This is particularly important for SVP boxing’s behind kitchen unit. Often the bottom of the SVP boxing is not sealed to the bottom of the floor so the air can escape straight out.
5. Bath and shower tray panels should be fitted and fully sealed.
6. All penetrations through floors & ceilings should be sealed.
7. The boiler flue must be sealed where it penetrates walls or ceilings.
8. Make sure all external door/window seals (if applicable) are installed.
9. In some houses, storage cupboards have been built into the roof space. The doors when closed should seal the room from the roof space. Fit draught excluder if necessary to top, bottom & sides of door/frame.
10. In houses constructed from Timber Frame or where DOT & DAB plasterboard has been fixed to the inside face of block work perimeter walls, the gap.
11. In between the bottom of the plasterboard and floors needs to be sealed at every floor level. Alternatively the gap between the bottom of the skirting board and floor can be sealed with mastic. This prevents air leaking behind the wall board and passing above the ceiling board, into the roof space.

Detail Showing the Main Air Leakage Paths

If you carefully check and prepare your building in-line with our air leakage checklist, it should help you pass your air tightness test at the first attempt. We have helped thousands of individuals and companies achieve their airtightness targets. Using our airtightness know how over many years of air testing and smoke surveys.

Whether you need air tightness test please contact us on info@aptsoundtesting.co.uk  to obtain a no obligation quote. If you need more information on how to prepare your building for the air test please download our air tightness testing checklist. 

Alternately, please visit our website at www.aptsoundtesting.co.uk  for more information on our precompletion testing services.

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.

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.

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: www.aptsoundtesting.co.uk  

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.

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 info@aptsoundtesting.co.uk.

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.

• Precompletion Sound Testing

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.

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: info@aptsoundtesting.co.uk  or visit our website at: www.aptsoundtesting.co.uk. Alternatively you can call Darren on 07775623464. 

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.

What is a BREEAM Thermal Imaging Survey?

We often get asked this question; basically when Thermal imaging surveys are used properly, they can discover a multitude of issues including:

• Areas of Thermal bridging
• Missing or damaged insulation
• Areas and pathways of heat loss
• Areas of damp and mould growth

Thermal Imaging Surveys on buildings are one of the most effective ways to monitor sustainability performance. By Undertaking infrared surveys on new build commercial or dwellings, clients can be assured that their buildings are efficient with resources, ensuring effective thermal performance from every angle

Thermal surveys can also identify potential improvements to reduce energy costs and CO2 emissions on existing buildings, thermography surveys can be used to assess the overall performance of the individual building fabric elements such that informed decisions can be made on improving energy efficiency. If required we can also undertake an in depth analysis, to estimate the potential cost and CO2 reductions if particular improvements are undertaken.

BREEAM Thermal Imaging Requirements

APT Sound Testing thermal imaging surveys are in accordance with the requirements set out in BS EN 13187. These requirements satisfy the BRE SD5076 standard for BREEAM credit, and a part of the survey you will need to allow for:

1. Adequate Temperature Difference

To help to ‘see’ heat loss using a thermal imaging camera, a 10ºC temperature difference between the inside and outside of a building must be achieved. If a building has no operational heating system, temporary heaters can be used as long as the temperature difference is achieved.

• Building Surfaces Must Be Dry at the time of the Thermal Survey

Before the thermal survey can commence all building surfaces should be dry to ensure that moisture evaporation does not alter the results. For building materials such as brick and/or block, its recommended that surfaces have been dry for at least 24 hours.

• Full Access to the Internal and External Envelope.

In order to effectively measure surface temperatures within a building, full access must be given to our thermal engineers in order to inspect outside walls and surfaces from the inside. In addition to this, obstructions such as furniture should be removed at least an hour before the start of a survey. This is to allow local temperature conditions to stabilise before the test commences.

• Avoiding Solar Radiation

To avoid the effects of solar radiation, thermal imaging building surveys should be conducted at least 2 hours after sunset or 2 hours before sunrise. This is important, as it means that thermal imaging surveys can be undertaken between 12pm – 3am during the summer months and 20:00pm – 6am during the winter months.

• Avoid High Winds

Thermal imaging surveys should be undertaken when winds do not exceed 5 metres a second (18kph). This is to stop the cooling effect from wind which may affect the accuracy of the camera readings.

A BREEAM thermal imaging survey will also demonstrate compliance with the construction specification on newly constructed buildings in-line with Building Regulations Part L and sustainability assessments such as BREEAM. A large number of Building Specifications are including a thermographic survey into the schedule of works as a means of quality assurance and to achieve the required sustainability rating.

Where anomalies are identified during the BREEAM Thermal Inspection, we can highlight the issues within our report and provide as much help as possible in identifying remedial work required to gain a credit for a BREEAM compliance thermographic survey.

BREEAM Thermal surveys are completely non-invasive and non-destructive meaning that the building suffers no mechanical or physical damage at all.

If you require a BREEAM Thermal survey our professional and certified Level 2 Thermographer’s will carry out your thermographic Inspections for BREEAM compliance in accordance with all necessary standards and current regulations, all we need are a few details such as floor plans and elevation drawings and the building location to provide a quotation. We will also send across our informative Thermal Survey Checklist to help you prepare for the thermal survey.

If you would like more information in regards to BREEAM Thermography Surveys, please contact us now at: info@aptsoundtesting.co.uk or call Darren direct on: 07775 623464.

Building Regulations Part L  and this link both offer lots of useful information in regards to Thermography Surveys. If you would like more information in regards to our Thermal Imaging Surveys, please contact us at: info@aptsoundtesting.co.uk or call Darren Direct on 07775623464.

Alternately, if you would like more information on how to prepare for your BREEAM Thermal Imaging Survey, please visit our website at www.aptsoundtesting.co.uk or Thermal Imaging Inspection Checklist and you can also reference our blog at: airpressuretesting.blogspot.com or our Thermal Imaging Knowledge Base Page which offers handy tips on how to prepare for your Thermal Imaging Survey.

What is an Air Tightness Test?
Air leakage (also known as air permeability or air infiltration) is the air tightness of a dwelling through uncontrolled means such as cracks and gaps in the building envelope – walls, floors and ceilings.

Any ventilation system installed within a building is classified as a source of controlled air flow and is therefore not considered as air leakage and so these areas can be temporarily sealed during the air tightness test.

Air leakage is often felt as unwanted draughts, which will lower internal temperatures and may cause discomfort to building occupants especially in cold and windy weather.

Air tightness testing is a method of measuring and quantifying the air leakage of a building. Building Regulations Part L1A relates to dwellings and Building Regulations Part L2 refers to commercial buildings.

Within the documents Air Tightness Testing is referred to as Pressure Testing and is the method by which developers measure the air tightness of their residential and commercial developments. Air testing shows how well properties will retain heat and in turn reduce carbon emissions, making them more efficient and cheaper to maintain.

An Energy Performance Certificate (EPC) is another compulsory requirement under Part L1A of the Building Regulations for all newly built residential and commercial units and these can only be issued when the air pressure testing results are available, to include within the SAP Assessment and thereafter the EPC.

How does Air Tightness Testing work?

Air Tightness tests are carried out by increasing the air pressure within the dwelling/building and then measuring the rate by which the pressure returns to normal. This is carried out using large fan/s inserted in the entrance doorway. The number of units you will have to test will depend on the number of unit types on your development. For most dwellings a single fan will be sufficient to pressurise the building; however, for larger commercial units a multi fan system will be required which is usually set up in blocks of 3 fans to each doorway.

What Air Permeability Figure do I need to achieve?

The Design Air Permeability for the dwelling/building will be determined initially by the lead consultant or SAP/SBEM assessor. The maximum design air permeability allowable is 10 m3/(m2.hr) @50Pa; however, this the more common figure of 5 m3/(m2.hr) @50Pa is often used. By aiming for a reduced Design Air Permeability and improving levels of air tightness it will serve to further reduce carbon emissions and make the Target Emission Rate (TER) easier to achieve. It may also mitigate the cost of more expensive carbon emission reduction strategies.

There are many common areas of air leakage; or air leakage paths within dwellings and commercial buildings, they are: Behind Bath Panels, Kitchen and Utility Units, Intermediate Floors, Behind Skirting Boards, Boxed in Pipes & Soil Stacks, Fireplaces, Poorly Installed Trickle Vents, Windows and Doors, Recess Lights & Loft Hatches.

Special attention should be shown to the above areas throughout the construction process.

Another interesting fact is that UK studies have demonstrated that a house/flat with robust air tightness credentials can often attain a higher sale price due to reduced energy costs over the lifetime of the building.

Building Regulations Part L and ATMMA TS1 both offer lots of useful information in regards  to Air Tightness Testing, such as which plots should be selected and what parts of the building can be temporally sealed etc.   If you would like more information on how to prepare your building to pass an air tightness test then please download our air tightness checklist.

Please Contact us now

If you would like more information on our air tightness testing service, then please visit our website at www.aptsoundtesting.co.uk or contact us at: info@aptsoundtesting.co.uk. To have a chat about your project please call:  01525 303905

Improving your Air Test with Good Construction Detailing

Air Testing is the simplest and most popular method used in the construction industry to confirm compliance with Part L of the Building Regulations. The air test is simply a test of the building fabric integrity. Draughts and heat loss often occur wherever there is a hole or gap in the building envelope, resulting in the loss of heat/cooling which in turn will add to energy bills.

Since April 2006, air testing has been required to be tested for Air Permeability, in order to comply with Part L1 & L2 of the Building Regulations.  Since 2011 the air leakage target has reduced from 10m3/hr/m2 to 5m3/hr/m2. In the next 2 years it is expected that the target may be reduced to 3m3/hr/m2.

We provide a personal, helpful, efficient and cost effective air test service to our clients. Using the latest high power, portable door fans systems, we offer air testing to all building types, ranging from small rooms, flats & houses to office blocks & large distribution warehouses in accordance with the Building Regulations Part L1 & L2

Our air test fan systems are compact, discreet and fit simply into a personnel door. The system can easily be transported through areas of limited access or up to high level areas. Many contractors use us to undertake the testing in busy city centres or other tight access areas as we eliminate the site disruption caused by the larger trailer type air testing equipment.

In the event of a building failing an air test we then offer smoke testing – both hand-puffer for dwellings and large scale smoke testing for commercial buildings. This highlights the areas of air leakage through the building fabric. We can then undertake a full written and photographic survey as reference for your site management and relevant subcontractors. We will also offer FREE advice on the best method to seal any leaking areas. The main benefits of this are:

•             Air leakage paths are quickly identified in the event of a test failure

•             A full written air leakage report is forwarded so remedial works can start straight away

•             Building handover/practical completion and handover can be achieved more quickly
 

Construction Phase Consultancy

Air Pressure Testing has a practical ‘hands on’ approach during building construction and prefers to be involved as practically possible during this stage. We undertake periodic site visits to inspect the building envelope assembly as it is constructed and provide both written and photographic reports to enable any further works / remedial works deemed necessary to be accurately targeted. Site visits are generally to allow us to identify:

•             Insulation placement, continuity and effectiveness at thermal bridge junctions

•             Air barrier continuity within elements and at interfaces (particularly at sub-contract  package interfaces) 

Foundation/ground floor Initial works (Air Test risk factor 8)

a.            Ensure that any penetrations through the air barrier (e.g. service pipes) have been dressed. Pre- formed collars, sometimes referred to as ‘top hats’, which seal to the membrane and around the throat of the pipes are effective means of achieving a good airtightness seal.

b.            Ensure that the wall and floor damp-proof course/membrane forms an adequate airtight layer.

c.             With using timber frame construction, check that the sole plate is sealed to the foundation/floor-slab.

Internal Floors (Air Test risk factor 9)

a.            Using joist hangers can limit penetrations through the air barrier.

b.            If joists are to be supported by the wall, check that there is no air leakage into the cavity and the wall between the joists is fully filled/completed.

c.             Ensure timber floor sheets/boards are well fitted and sealed at their edges as well as at junctions with perimeter walls with mastic.

d.            Ensure the ceiling-to-wall joint has been sealed with mastic.

Eaves Level (Air Test risk factor 8)

a.            Ensure the airtightness layer between the wall and ceiling/roof is continuous ceiling below the roof space.

b.            Ensure there is a continuous air barrier over the whole ceiling area.

c.             Ensure all service penetrations (ventilation ducts from extract fans and light fittings) have been properly sealed where they penetrate the air barrier as this is a major air leakage path.

d.            Ensure all loft hatches are airtight and surrounds are sealed where they penetrate the air barrier.

External Doors & Windows (Air Test risk factor 7)

a.            Ensure you always specify good quality windows and doors.

b.            Always check that the wall-to-frame junction is properly sealed and continuous with mastic against the wall’s airtightness layer

c.             Ensure all windows and doors have an appropriate weather-seal between the opening unit and the frame – check for missing weather seals.

d.            All external doors should be fitted with draught excluders.

e.            Ensure the letterbox is fitted with a draught excluder.

Envelope Service penetrations (Air Test risk factor 10)

a.            Check for seals at service entry points (pipe and cable routes), e.g. around incoming water pipes,  gas pipes, electrical cabling, as well as waste water pipes for sinks, baths, washing machines,  dishwashers, etc. Seals should be provided internally and externally.

b.            Where multiple services penetrate at the same point, there should be sufficient space to fully seal round each of them.

Brick/block masonry construction (Air Test risk factor 7)

a.            Ensure the quality of construction as the work proceeds. Good mortar joints are required (i.e. no gaps around the blocks or bricks) on both internal and external faces – this also reduces sound transmission.

b.            Ensure all block-work is paint grade and painted were possible.

c.             The application of wet plastering, parging or the addition of fully-sealed dry lining will create a good air seal.

d.            Parging is an effective method of sealing around joists that penetrate the inner leaf of an external wall.

e.            Check that there is a good seal around all services that penetrate the masonry.

Plasterboard Dry lining (Air Test risk factor 10)

a.            Check the plasterboard is continuous (e.g. there are no large holes behind the kitchen units/bath). 

b.            Ensure that airtightness measures have been incorporated at all edges, particularly at the floor/ceiling junctions and around openings.

c.             Check the plasterboard is correctly detailed at joints, corners, reveals and window sills. Plasterboard should be mounted on ribbons of plaster or adhesive around all the edges (rather than dabs) to  prevent air leaking through the porous block-work behind.

Sealed Membranes & Vapour barriers (Air Test risk factor 9)

a.            Where the vapour barriers have been used as the air tight barrier, check that it is complete, that all joints have been sealed and it’s not damaged.

 Timber frame construction (Air Test risk factor 8)

a.            It’s usually easier to make timber frame dwelling airtight than other forms of construction. This is partly due to pre-fabricated construction and the use of the impermeable vapour barrier as the air barrier. The plasterboard layer can also become an air tight layer.

b.            Where vapour barriers have been used special care will be needed to avoid it being torn. Any damage to the vapour barrier must be carefully repaired.

Remedial Air Sealing Solution

1.            Smoke Investigation with Air Testing Fans:

APT’s Air Sealing Team utilise smoke investigation to identify the air leakage paths and prioritise which can be sealed first to attain an air test pass.

2.            Remedial Air Sealing Works:

APT can carry out the air sealing works. Typically allow for a 2-4 man Remedial Air Sealing Team. Adequate access must be provided for all sealing works. We provide all air sealing Materials – Rates provided on Request.

3.            On-going Air Tightness Assessments:

Enables the APT Sealing Team to seal the building until the fans indicate that the air

test would pass – thereby minimising the remedial works and time on site.

4.            Final Air Test:

APT’s Air Test Technician carries out a final independent test for compliance.

Whether you need a full on-going air tightness design/consultancy service, or just a simple air test, Air Pressure Testing have the knowledge and experience to ensure your building passes first time.

If you are unsure of the air tightness services you require, please visit our website – http://www.airpressuretesting.net/, call us on 07775 623464 or e-mail darren@airpressuretesting.net and one of our Air Tightness Consultants will guide you through the process, ensuring that you receive the right level of advice at the right time.

How Many Air Tightness Tests do I need on my London Project?

The air tightness test can be carried out on a selection of dwellings/ building types – three units of each type or 50% of that type, whichever is fewer. It many cases it is necessary to test all plots, otherwise a 2m3/hr/m2 penalty must be applied to all the plots on the site, this means that you will need to 3m3/hr/m2 if your SAP report stipulated a designed air permeability rate of 5m3/hr/m2. So to summarise the following testing will usually be required:

• All new dwellings (based on a sampling rate)
• All commercial new buildings other than dwellings
• ‘Large’ extensions to buildings other than dwellings (if the footprint of the building extension is 25% of the original buildings floor area)

The dwelling(s) to be tested should be taken from the first completed batch of units of each dwelling type. For a dwelling to class as the same’ type’ as another it should consist of the following:

• The same generic form, i.e. detached house, end of terraced, mid-terraced, semi-detached, ground floor flat, mid-floor flat, top floor flat, bungalow etc.
• Have the same principle construction details
• Have an envelope area that does not differ by more than 10%
• Include the same number of storeys
• Have the same Design Air Permeability (Air Pressure Test Target)
• Have a similar adjacency to unheated spaces such as garages, unheated stairwells etc.
• Have a similar number of apertures and penetrations, for example doors, windows etc.

To help builders and developers, there are two building standards that provide in depth information in regards to air tightness testing, they are Building Regulation Part L and ATTMA TS1 & ATTMA TS2

What is my Designed Air Permeability Target?  

Building Regulations Part L1A and L2A are specially aimed at new buildings and most are now required to have an air-tightness test. Part L1B and L2B cover work to existing buildings and do not generally have a requirement for air-tightness testing.

All new dwellings are required to have a SAP (Standard Assessment Procedure) calculation prior to building control approval. It is ultimately the SAP calculation that determines the air permeability target needed to be achieved and whether it is a requirement.

All new non-dwellings are required to have a SBEM (Simplified Building Energy Model) calculation prior to building control permeability targets and will require testing.

The design stage SAP and/or SBEM assessments provide the required ‘air permeability rate’ you need to achieve on the project. Clients often mistake the maximum permissible air permeability rate of 10m³/hr/m² as their target; however it’s the ‘designed air permeability rate’ which you need to adhere to, which is usually much lower than this at around 3m³/hr/m² to 5m³/hr/m². If your project is in London, the requirements are often more stringent. Most air tightness tests in London need to achieve 3m³/hr/m².

We are here to help you with your Air Tightness Test in London

If you are unsure how many London air tightness tests you require, please contact our friendly expert team for advice on helping properties achieve required emission rates for air testing. Simply the use our contact form on this page, or call our offices, to chat about your specific air testing requirements with our knowledgeable team of air tightness consultants.

APT Sound Testing can assist you through the process and help you determine the specific air tightness testing requirements for your project. If you require more information please visit our website at www.aptsoundtesting.co.uk

Different Types of Sound Testing
Sound Insulation Testing needs to be carried out between pairs of rooms separated by party walls or floors. In most cases the rooms to be sound tested will be the two main habitable rooms – living rooms and bedrooms. The sound testing 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.

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.

There are two mains types of sound tests that need to be carried out prior to the building handover, they are:

Airborne Sound Tests
Airborne sound tests  are usually 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. From the results, the airborne sound insulation (DnT,w + Ctr) is calculated and compared to the requirements of Approved Document E. For new build projects you are required to achieve 45dB for airborne sound testing through walls and floors and 62dB for Impact sound testing for floors. For refurbishment projects this changes to 43dB for airborne and 64dB for impact.

Impact Sound Tests
For vertically separated rooms, an Impact sound test 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. From the results, the impact sound insulation (L’nT,w) is calculated and compared to the requirements of Approved Document E.

Airborne Sound Testing of Building Facades
For the sound testing of external facades we place the loudspeaker outside  the  building  at a distance of 5m from the facade with  the  angle  of  sound incidence  equal  to  45° ± 5°  and  such  that  the  real  traffic  noise  impact  is simulated  the  best  possible  way.  The speaker and amplifier are used to generate a steady random noise signal via the loudspeaker source. The sound pressure levels are then measured at 2m in front of the facade plane and 1.5m above the ground.

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

If you would like more information in regards to the Different Types of Sound Testing please contact us 01525 303905 or visit the APT Sound Testing website today.