Air tightness testing, also known as air leakage testing or air permeability testing, establishes the rate at which air flows out of gaps in a building fabric. Since Approved Document L was reviewed in 2006, air tightness testing has become an essential part of building regulations for newly completed and rehabilitated buildings.
Revisions were made to building regulations to address air leakages – a process where air escapes through any opening in the building, affecting its energy efficiency. Our certificates are registered with the Air Tightness Testing and Measurement Association (ATTMA), an organisation that guarantees technical excellence in all air leakage measurement methods. Located in Church-End, our company is a committed and accredited air permeability testing service provider; we provide air testing services. You can also contact us for assessments and consultancy services. In addition to air leakage testing, we provide Part F Mechanical extract fan flow rate testing.
As registered members of the ATTMA, our air tightness certificates are accepted as proof of building regulations sign-off. Not only do we test the air permeability of your building, we describe the procedure in a professional manner and advise you on problem areas discovered during the evaluation. Our goal is always value for money and customer satisfaction. We are professionals and our services are of the highest quality.
When a building is assessed during an air tightness test; the internal thermal envelope of the building is examined for leakages and the quantity of air passing through it. Air tightness testing is also known as air pressure testing or air leakage testing. Air leakage, also known as infiltration or draught, allows air to pass through unwanted leaks in a building; unlike ventilation where the air inside and outside of a building and its flow from one end to the other is controlled. Draughts are uncontrolled ventilation. Using air tightness testing, the total air lost can be estimated. Too much air leakage leads to unnecessary heat loss and discomfort for the occupants. As Government strives to reduce CO2 emissions from new buildings, building regulations now place greater emphasis on reducing air leakage from the building envelope. This reduces fuel consumption and CO2 emissions. Air tightness testing is vital in determining the energy efficiency of a new building, air leakage and the build quality. Building plans will often consider air tightness at the beginning stages of development so as to measure up to stricter building standards. Understanding this at an early stage can make a build cost-effective, of high quality, and energy efficient by minimising uncontrolled air leakage.
Air leakage is uncontrolled air movement in a building due to cracks. Air leakage is the uncontrolled movement of air into and out of a building through gaps and spaces in the building’s fabric. Also known as infiltration, it is different from ventilation, which is air that enters a building in a controlled manner. It may cause uncontrolled influx of air during frosty and windy weather. This reduces the temperature of the building, making the occupants uncomfortable. Air leakage plays a major part in the energy efficiency of buildings, and testing is necessary as a means of demonstrating that the air tightness targets used in building energy calculations have been achieved. In England and Wales, air tightness testing has been obligatory since 2006. All new dwellings and non-dwellings over 500m² are to be tested for air permeability.
Heat loss within a building can be caused by air leakage. During windy weather, cold air infiltrates a building through the openings in its fabric. This results in heat loss. It doesn’t stop there. Warm, damp air within the building escapes the gaps in its envelope. The warm air is filled with moisture, which hits the inner wall surface and condenses. Moisture is sucked into the building material, and this can lead to serious structural issues. The strength of the outer wooden covering is drastically reduced because it is wet.
Over time, any of these conditions can cause structural damage.
Other impacts include:
The most effective method of lessening the damage caused by moisture is to control the flow of air into and out of the building. Air leakage and vapour diffusion are minimised when barriers are installed. Passive or active ventilation is required to reduce water vapour, moisture odour and pollutants.
Air tightness is an important factor in a building’s energy efficiency and is part of government’s plan to battle environmental change by regulating the energy performance of buildings. Environmental change caused by carbon dioxide emissions and global warming is partly aided by the burning of fossil fuels to generate heat. The best way to reduce the quantity of fossil fuel burnt is by stopping air leakage which reduces heat loss. Poor degrees of ventilation and high levels of uncontrolled air leakage encourage mould growth and excessive moisture. This could potentially cause medical issues. Best practice advice is to “Build tight, ventilate right”. Excess air leakage leads to moisture in the building envelope, causing large repair expenses and medical issues because of mould.
Best practice says that air tightness tests should be carried out early in construction and after the final phase. The results of the test are used in SAP and SBEM calculations, and can influence a building’s overall energy rating. For big residential developments, the test is not required for each house. A group of diverse buildings are picked for the test. With selective testing there is a penalty of +2m3/h/m2; if the target score is 5 m3/h/m2 and selective testing was applied, the air tightness test would have to achieve a lower score of 3.
buildings that have not been tested are assessed for air permeability based on similar dwellings’ test scores +2m3/h/m2 at 50 Pa. Because selective testing does not conduct tests for all buildings, a tested building might have a much higher air tight rate than an untested building; making it unreliable. The 2m3/h/m2 penalty added to untested buildings makes the air permeability rate hard to achieve.
Business owners and home owners in Church-End have been helped by AF Acoustics air tightness testing. Our customers highly recommend us to other people due to the following benefits.
Due to years of experience in conducting air tightness testing in different kinds of buildings in Church-End, we have the skills to meet your needs no matter the type or size of your property. Our accredited air testing experts are polite and competent. They are trained to provide the service you need and fit around your project. Our knowledgeable and dependable air testing experts will provide lasting solutions to your problem. Call AF Acoustics for your air tightness testing.
We are registered members of the ATTMA, a professional association dedicated to promoting technical excellence in air tightness testing and air leakage measurement applications. This means our expertise and quality of services are recognised by the leading air tightness testing body in the UK.
Our comprehensive air permeability testing in Church-End is available. We offer responsive scheduling. Schedule for your building to be tested at your convenience. There won’t be delays or complications once you’ve fixed a time.
In order to satisfy our clients, AF Acoustics strives to provide test results and certificates on the next day.
Save money by paying lower rates at AF Acoustics. As a business with low overheads, we’re able to give you one of the best air leakages testing services in Church-End at reduced costs.
Whatever the type and size of a domestic or commercial building in Church-End, AF Acoustics’ experts can test it for air permeability and issue an ATTMA certificate afterwards. Air permeability testing calculates how much air moves through spaces in your building’s fabric. The result of the air leakage test is expressed as a quantity in the form of The test results are described as m3/h/m2 – (m3 per hour) per square metre. of a building envelope.
Air leakage testing is a requirement of Approved Document L1A and L2A. Each building tested must achieve a maximum air permeability rate of 10m3/h/m2. In order to comply with the carbon emission target, it may be necessary to achieve a lower air permeability rate. The required air permeability rate for each building can be found on the design-stage SAP assessment or SBEM for that building. Excessive air leakage causes discomfort due to heat reduction and carbon dioxide discharge. It also creates convective loops within a building’s internal structure, leading to energy loss. The warm air within a building rises, leading to the influx of cold air through gap, cracks and other openings in the building envelope. The increasing difference in air pressure results in infiltration and exfiltration of air. To limit exfiltration and infiltration, the law requires that domestic buildings take air leakage tests. The buildings must be energy efficient and signed off by building control in Church-End. With air leakage tests, business areas are more comfortable for employees and customers. This increases the company’s productivity and lowers heating and cooling expenses.
Since Approved Document L was reviewed in 2006, building regulations have demanded that new and rehabilitated constructions conduct air tightness test. Other names for air tightness are air permeability rate or leakage rate. Air leaks through gaps and spaces in the building fabric such as service penetrations, walls and roof junctions. Sometimes, this is not obvious to occupants. Part L of the Building Regulations requires that all commercial buildings greater than 500m2 undergo air tightness testing and a selection of residential buildings in a development be tested. To adhere to Part L, make sure your building’s air permeability rate is not greater than 10m3/h/m2. Air tightness is important for meeting the Building Regulations Part L standards, exceeding requirements for low carbon buildings, and overall energy efficiency.
We will ensure that you exceed all the Parts L and F standards. Not only will we conduct your air tightness test and extract fan flow rate test, we will also recommend experts who can handle your SAP calculations, water calculations and Energy Performance Certificates satisfactorily.
Approved Document F of the Building Regulations demands that all mechanical extract fans in newly completed constructions undergo a flow rate test. Building Control Body (BCB) will see proof that the test has been conducted before signing off your building. There are 3 available methods for examining, recording and reporting the testing of extract fans. Using a vane anemometer, our testing procedure follows Method 3 – The minimum benchmark method.
There are several levels of air leakage testing based on the kind, size and multifaceted aspects of a dwelling. Here they are: A single blower door fan is used for air tightness testing for single buildings and smaller non-dwellings not more than 4000m3. Level Two: Single and multifaceted buildings 4000m3 gross envelope volume and above are tested for air pressure. High rise (LCHR) buildings and phased handover/zonal buildings are excluded from this level. Air tightness testing for phased, zonal handover and LCHR constructions is done.
Air tightness testing determines the extent of air leaking out a building’s envelope. The result is expressed as a quantity in the form of m3 per hour, per square metre of building fabric. Air tightness testing is required for new builds. A lower air permeability rate might be needed due to carbon emission requirements. The required air permeability rate for a dwelling can be found on the design-stage SAP report for that dwelling. Too much air leakage leads to heat loss which can lead to draughts and higher energy bills.
Air pressure testing involves the calculation of air escaping through the openings in a building. The result is expressed as a quantity in the form of air pressure (m3 per hour) per square metre of building fabric. Document L2A of Building Regulations declares air leakage testing to be mandatory. The highest air permeability rate for your dwelling when tested should be 10m3/h/m2. The result of your dwelling’s air permeability rate might have to be lower than required due to SAP or SBEM assessment. You can find the required air permeability rate of your building in its design-stage SAP or SBEM assessment. Too much air leakage leads to heat loss (and consequently, higher CO2 emissions) and draught.
To ensure that the auto opening vent will perform optimally when fitted and commissioned, we test the smoke shaft to verify its air tightness. Automatic opening vents help storey buildings dispel smoke when there is a fire. The performance of the fans and vents depends on the air tightness of the shaft. Air tight shafts have enough pressure difference to extract smoke and save people inside a building during fire emergencies. We work towards air permeability targets set by the automatic-opening ventilation manufacturers that allow their equipment to operate effectively. The shaft undergoes air leakage testing when fans are placed inside it. Once the fan is fixed, the extract points and ventilation grilles on each storey are sealed to ensure that the shaft is in proper condition. Once the test is completed and successful, the automatic opening vents are installed.
Buildings that are well insulated and air tight are the standard for buildings. As a result, a high-quality ventilation system that is adequate and performs as required is vital. We test fan extraction rates. This has not only been made compulsory by Building Regulations; it also helps reduce humidity in rooms, bathrooms and kitchens and expel pollutants. The air flow rates of all intermittent extractor fans, which are to be installed during the building process, are to be tested and the results submitted to the Building Control Body before work is completed.
Air tightness tests calculate the level of air leakage a building has and if it is excessive. The greater the air tightness of a building, the more comfortable the occupants are and the higher its energy performance.
Gaps and cracks in the building that cause air leakage are often difficult to detect. They may be obscured by the internal building finishes. If you know the leakage paths of a building, you will know if it is air tight.
Under the new regulations developers must test 20% of the dwellings on a site but this also depends on the amount of differing house types to ensure that a consistent sample is taken throughout the construction of the development. There is a penalty for untested constructions. Therefore, we suggest air leakage tests for all buildings.
Clients should send the drawings (plans and elevations) and air permeability requirements to our engineers. An Air tightness test can be done in 30 – 60mins. Wind speed should not exceed 6m/s. Test engineers need to know the size of a building envelope and requirements before coming to the site. To get the site ready, make the place air tight by closing and securing all external doors, windows, ventilation and smoke vents. Remember to turn off range cookers or stoves a day before testing as well as mechanical ventilation systems, and fill all drainage traps.
Before coming to the site, we get the measurement of the building’s envelope. A building envelope is the boundary between the conditioned and unconditioned environment of a building. We use the building envelope measurements to get the right results when testing for air tightness.
Air permeability is measured as air leakage per hour per square metre of the building fabric at a pressure differential of 50 pascals (50n/m2). The air barrier envelope area is the total area of all the floors, walls and ceilings both above ground and underground. The internal dimensions of the building found in the drawings are used to calculate the envelope area and subtractions are not made from the areas of floors and ceilings with or without external walls or from the area of the junctions of internal walls.
Air changes per hour are crucial to ventilation design, but it is only occasionally used as the base for the design or calculation. Residential ventilation rates are calculated based on area of the residence and number of occupants.
The area of the roof and ground floor should be the same. A cold roof is a roof that has the thermal insulation put in the ceiling with wide space between the insulation and pitched roof rafters.
A warm roof has the insulation running along the pitched roof rafters with an air barrier normally running parallel along the inside face of the insulation. The envelope area is the boundary or barrier containing the overall internal ‘conditioned space’ separating it from the external environment (or non-conditioned spaces and adjacent buildings), and this is located on the warm side of the insulation.
Examine the wind speed, barometric pressure and temperature. Place the fan on an aperture within the building envelope. Fix the instrument for testing. Note the air flow volume from the fan. This is the same as the air leakage from the building envelope. Gradually increase the speed of the fan to a maximum of 55-60Pa. Note the difference in air pressure in several parts of the building at each fan speed.
Our air leakage measurement involves picking out the gaps where air leakage takes place, recording the test information, sending results to customers in a technical report and advise clients on repair methods in the case of a test failure. Air Pressure Testing & Compliance
A low leakage building that is properly ventilated, whether natural, hybrid or mechanical, is very beneficial. The benefits are: Reduced heating expenses because of lower heat loss, with less need for equipment that has high heating ability. Better performing ventilation system Your building will have less mould since moisture cannot escape into holes and cavities. Thermal comfort is enhanced because air infiltration is lower. Our clients can expect a stress-free conformity to Part L Building Regulations standards, whether they have a single building or a large commercial building. We render cost-effective services that include air leakage tests, design reappraisal, consultancy and support services for dwellings and non-dwellings in Church-End.
When constructing a new building, it should be built air tight, as stated by Building Regulations – Approved Document L1A. The regulation is focused on the conservation of fuel and power usage. Part L1A has demanded that all new dwellings be tested for air leaks in line with other regulations.
During air leakage tests, there are technical standards that must be used. This was mandated by ATTMA – Air Tightness Testing and Measurement Association–to align with building regulations and other rules. They explain in detail and provide guidelines for BS EN 13829:2001: “Thermal Performance of Buildings. Determination of air permeability of buildings. Fan pressurisation method” and ISO 9972:2015: “Thermal performance of buildings – Determination of permeability of buildings – Fan pressurization method”.
Undergoing an air tightness test is compulsory for your new building, according to Part L of Building Regulations. For development with two or more buildings, three units of each dwelling type or 50% of the dwelling type should be tested. If there are no more than two new dwellings, using an assumed value of 15m3/h/m2 in the DET/TER calculations might exempt them from air tightness testing. Find out from your SAP assessor if this is applicable to you. There are different ways that Dwellings and Non-Dwellings should be tested. ATTMA TSL1 and ATTMA TSL2 have clearly stated these. Air tightness tests are to be carried out on all residential developments (all the buildings or a selected group) and all certain Non-Dwellings. If your building has added an estimated assessed rate of 15 m3/h/m2 in its calculations or its useful floor space is less than 500 m2, it may not have to take the test.
Most competent air pressure testing companies go through the ATTMA scheme, which began in January 2015, etence. The scheme is endorsed by the government and recognised by approved documents L1 and L2 of building regulations. Its basis is the National Occupation Standard (NOS) and Minimum Technical Competence (MTC) documents standard for testing and essentials for testing knowledge.
Air leakage test reports are given by authorised organisations that test different buildings. The testing companies seal extraction fans. After the test has been completed, they record test findings and results in a report. This is done according to the testing organisation’s procedures and Building Regulation standards.
AF Acoustics will ensure the test result is written in accordance with the test standard requirements, identify any deviations from the relevant standards within the report and check air tightness against target value. Clients’ test reports contain their names, construction, address; the tester’s name is also included. In the event that a building fails the test, we suggest methods of improving the building and what repairs to do on the building fabric if a retest is required.
Before our test engineers arrive at the site, please adhere to what is written below and send the required air tightness target of your dwelling that is in the design to us.
Air Leakage Pathway Checklist – Check will be done for visible leaks in the following places:
Air leakage is the uncontrolled flow of air through gaps and cracks in the fabric of a building (sometimes called infiltration or draughts).
This is not to be confused with ventilation. Which is the controlled flow of air into and out of the building through purpose-built ventilators that are required for the comfort and safety of occupants.
Too much air leakage leads to unnecessary heat loss and discomfort to the occupants from cold draughts.
At AF Acoustics, we will endeavour to help you identify air leakage/infiltration paths.
There are a number of methods we employ to do this, including:
In the vast majority of cases the first two methods are sufficient to identify the most significant air leakage paths along with our expertise we will be able to point our the problem areas should they arise. The air leakage areas will have to permanently sealed and the test repeated to reduce the air permeability of the building. Where problems are larger and sealing cannot be addressed on the day, the building may need to be re-tested at a later date.
A test certificate from The Air Tightness Testing and Measurement Association (ATTMA)
A testing procedure is to be carried out to comply with TSL1 for domestic or TSL2 for commercial. The test certificate will include sufficient information to describe the building tested e.g. location, type and size (the envelope area is an important component in calculating the air permeability and must be accurate) plus the design air permeability as well as the actual result. A testing procedure should be representative of the actual building performance.
An indicative result is available at the time of testing. Certificates can be issued within a day of testing.
If required, you can request all calculations including pre, and post environmental measurements, individual static pressures, envelope area breakdown, flow readings and calibration certificates at no extra charge.
Air permeability is essentially a function of the pressure difference between the inside and outside of the building and the air flow rate through the fan(s), necessary to produce a pressure difference. This is averaged out over the envelope area. The result takes account of environmental conditions.
The final air permeability at 50 Pa is based on a logarithmic graph of pressure difference and flow rate, the graph should:
These are aspects that the building control should check carefully if choosing to accept air permeability results from non-accredited testing bodies.
Most air tightness tests for domestic units and simple commercial units are carried out in 45 – 60 minutes. This time may be extended if the test fails and leakage paths are investigated. We will normally charge for a retest depending on how much work is to be carried out.
On larger commercial units, which require 1 large air test fan, air tests take 1 hour if all temporary sealing has been completed prior to starting the air test.
If complicated or very large buildings are being air tested with multiple fan units, allow up to 4 hours for the test and longer if investigations are required.
The envelope area is calculated from the drawings and verified on site. The envelope of the building is all the surfaces that separate the heated interior from the unheated exterior of the dwelling. This includes walls, floors and the roof.
Generally, this involves mounting a door profile and incorporating one or more electrical fans into an external door opening(s). Depending on their orientation, the fans can be used to pressurise or depressurise the building. The resulting difference between the external and internal pressure can be used to calculate the permeability of the building envelope (given that the envelope area is known).
This permeability is an indicator of how air tight the building is, and whether there are openings in the envelope. Generally, 10 differential pressure points are taken at different fan flows to establish an accurate result for the building. Our certified specialised software is used to establish an accurate Air Tightness Test result.
Our experts at AF Acoustics will provide a simple checklist for building preparation, which includes the following:
All building preparations should be made before our test engineers arrive on the site this will ensure a smooth testing process and increase your dwelling’s chances of passing the test the first time. We will seal all the vents ourselves.
For multiple dwellings it may also be necessary to agree on the test programme with the building inspector before arriving on site.
Where possible, it is helpful to accurately calculate the envelope area and confirm the fan installation arrangements based on architectural drawings before coming to the site.
For dwellings, sufficient information is required to identify the different dwelling types and the number of each such as General Arrangement/Site Plan and Schedule (including other important details such as variation in storey height or construction method).
For buildings other than dwellings, the approximate envelope area is the key factor for quoting. It is required to establish the necessary fan arrangement. This affects the time on site and potentially the number of people, and this can be calculated from drawings – floor plans and elevations.
The testing body may also need to identify the potential aperture(s) into which test equipment is to be installed. In some circumstances this may require additional time on site, extra people or customised templates.
Approved Document L states that Building Control can accept evidence from BINDT or ATTMA Registered testers. However, the BINDT scheme was closed down at the end of 2014, subsequent to the last revision of Approved Document L. Additionally, The Independent Air Tightness Testing Scheme (iATS) is an authorised Competent Persons Scheme created for companies (including sole traders and partnerships) that carry out Air Tightness Testing.
The common leakage sites are:
All pipe works within the kitchen and bathrooms
Our team of experts can support you through the following
Additional AF Acoustics services – including noise survey, sound insulation testing services noise impact assessments
Employing the services of a reputable and accredited air tightness testing consultant, such as AF Acoustics, can help identify and remedy potential problem details in a building design prior to and during construction.
The Air Tightness Testing and Measurement Association (ATTMA) is approved by Department for Communities and Local Governments (DCLG) and is listed in the Building Regulations as an authorised Competent Persons Scheme for air tightness testing.
As an ATTMA registered company, AF Acoustics is independently certified by ATTMA with a scope covering air tightness testing to the ATTMA Technical Standards (TSL1 & TSL2) and BS EN: 13829 (2001), demonstrating knowledge and understanding, which enables us to test both commercial and domestic developments in accordance with relevant building regulations.
Part L sets the energy efficiency standards required by the Building Regulations. It controls:
It also sets out the requirements for SAP (Standard Assessment Procedure) Calculations and Carbon Emission Targets for dwellings. In addition to insulation requirements and limitations of openings of the building fabric.
Part L also considers:
Building Regulations are administered separately in England, Scotland and Wales.
The objective is to measure the volume of conditioned air escaping through the building envelope via uncontrolled ventilation at an induced pressure difference of 50 Pa. A simplified process is shown below:
No. However due to the penalties occurred to the air permeability value of non-tested properties, every property is usually tested. We can test all dwellings, including domestic buildings, industrial units, warehouses, schools, hospitals, residential care homes, hotels, offices, and retail units.
All new buildings and dwellings should be tested, but there are some exceptions and they are explained below:
No. Air tightness testing applies to:
Air tightness is an important factor in assessing the overall carbon emission of a building via the appropriate calculation methodology:
When a building is air tight, the amount of fuel needed to heat it is reduced. This conserves fuel and reduces the carbon dioxide produced, thereby lowering carbon emission and energy bills.
If you are building a new domestic property or commercial property of a certain size, it will need to undergo air tightness testing. This assesses the building for ‘air permeability’, checking for air leakage through gaps, holes and other areas. The Government has SAP (Standard Assessment Procedures) in place for air tightness testing, setting standards buildings must comply with to be energy efficient.
All residential properties and non-dwellings properties over a certain size (with a floor area greater than 500 m2) must undergo air tightness testing. With larger developments, a sample number of the buildings must be tested, depending on the size and construction of the properties. However, in practice all dwellings are likely to be tested, as non-testing attracts a severe penalty.
In a property where air tightness is below the recommended standard, the following problems can occur:
AF Acoustics lead air tightness testing Specialist, Gerard is your first port of call for all air tightness questions enquiries and surveys.
