Air tightness testing, also called air leakage testing or air pressure testing, calculates the quantity of air escaping through openings in a building. Air tightness testing has been a compulsory part of the building regulations for new dwellings, renovations and commercial projects since the revision of Document L in 2006.
The energy performance of a building can be affected by air leakage. To address this problem, alterations to building regulations have been made. 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. We are a dedicated and approved air leakage testing service in Strand-on-the-Green and we can provide air permeability measurement whenever you require. You can also call or email us for any of these services:
We are registered members of the ATTMA. As a result, our air tightness certificates prove that the building requirements for your building have been met. We don’t just provide air tightness testing. We describe the process thoroughly, give expert advice on areas that could be problematic during testing, and suggest improvements based on the air permeability rating of the building. 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. Other names for air tightness testing are air leakage testing and air pressure testing. Air leakage is the draught or infiltration of unbridled air through the spaces and openings in a building. It is different from ventilation, which is the contained circulation of air within and outside the building. Air leakage is uncontrolled ventilation. Air tightness testing is the approved method for gauging the entire air that has leaked through a building fabric. Too much air leakage leads to unnecessary heat loss and discomfort for the occupants. The government aims to lessen the quantity of air flowing from newly built buildings. Therefore, regulations have been put in place to reduce uncontrolled ventilation from the building envelope, sustaining the right temperature conditions without using so much fuel. With air tightness testing, you can determine whether or not air is leaking from a building’s envelope, the build quality and energy efficiency of new developments. Building plans will often consider air tightness at the beginning stages of development so as to measure up to stricter building standards. Incorporating this at the beginning of the construction process makes the development more cost effective and energy efficient.
This occurs when openings in a building lead to excess air flow into and out of the building. It is not the same as ventilation which is regulated air flowing into a building. It is also called infiltration. It leads to heat deprivation when cold draughts happen and warmth is needed the most. Because air leakage is uncontrolled ventilation, excessive air flows into the house during windy and wintry weather. Air leakage and a dwelling’s energy efficiency are intertwined. Testing is needed to verify that air tightness levels used in the building’s energy calculations align with the targets required by the law. Air tightness testing is compulsory for all new constructions and non dwellings with a floor area over 500m² in England and Wales. This came into effect in 2006.
Air leakage causes heat loss. Heat loss is caused by influx of frosty outside air into a building through the openings in its envelope during draughts and cold weather, leading to an uncomfortable drop in temperature. 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. Wooden sheathing or overlay becomes wet, making it weak.
As the years go by, these conditions can result in structural damage.
Air leakage can also cause these problems:
These effects can be mitigated by controlling the circulation of air into and out of the building. The potential of vulnerable wall structures to absorb condensed moisture is reduced when air barriers are properly installed and uncontrolled air flow is reduced. Passive or active ventilation is required to reduce water vapour, moisture odour and pollutants.
Air tightness is a key factor in building energy efficiency, and is a part of government-led initiative to combat climate change through improvements in building energy performance. Heating buildings contribute to global warming and CO2 emissions, since fossil fuels are used to create heat. Reducing air leakage reduces heat loss, which in turn reduces the amount of energy a heating system uses. Properties with uncontrolled air leakage also cause health issues. A building with poor ventilation and high air permeability is conducive for moisture and mould growth which can affect the inhabitant’s health. A great option would be to build tight and ventilate right. High levels of air leakage can lead to moisture ingress into the building fabric, resulting in expensive repair costs and potential health problems due to mould.
A building should ideally be air tightness tested early in the construction process and again at the end of the building project, although sometimes only the final check is carried out. The results of the test are used in SAP and SBEM calculations, and can influence a building’s overall energy rating. Larger residential developments do not require testing to be completed on each individual property, instead, testing is undertaken on the different dwelling types within the development. This type of testing attracts a penalty of +2m3/h/m2, consequently, if the target result is 5m3/h/m2, a lower score of 3 would have to be attained.
buildings that have not been tested are assessed for air permeability based on similar dwellings’ test scores +2m3/h/m2 at 50 Pa. It’s better to test each property because selective testing does not give a realistic picture of individual buildings. Besides, air permeability rates are difficult to achieve for untested buildings in such areas due to the +2m3/h/m2 penalty.
With AF Acoustics, homes and businesses in Strand-on-the-Green have been getting quality air tightness testing. We come highly recommended by our clients because of the following guarantees.
Our experience in serving diverse customers in Strand-on-the-Green is proof of our ability to satisfy your requirements no matter the size and type of building, or your circumstance. We have competent and accredited air testing professionals who provide a quality, convenient service. Our personnel will use their expertise to provide lasting solutions. Contact AF Acoustics in Strand-on-the-Green –the right team for your building.
We are registered members of the Air Tightness and Measurement Association (ATTMA). ATTMA encourages proper air leakage applications and promotes quality air tightness screening, and has recognised our impeccable professional services.
You can access our complete air tightness test in Strand-on-the-Green at anytime. Pick a time that is convenient for you in our responsive scheduling options. We guarantee no delays or complications regarding scheduling.
AF Acoustics offers trustworthy and expert services. We know that clients want to receive their test results quickly. As a result, we endeavour to deliver test certificates by the next day.
AF Acoustics, a small business with low overheads, offers one of the best prices in Strand-on-the-Green and guarantees professional services.
All domestic and commercial buildings in Strand-on-the-Green can be tested by AF Acoustics, no matter how complex they are. The air tightness tests are carried out by competent testers and you will be issued an ATTMA certificate. The best way to determine how much air seeps through a building’s fabric is through air permeability testing. The result 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 building fabric.
Air tightness testing is recommended by Approved Document L1A and L2A. A maximum air permeability rate of 10m3/h/m2 is required. However, a building has to achieve a lower rate to meet the carbon emission target. To get your building’s required air permeability rate, check its design-stage SAP assessment SBEM. 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. Infiltration/exfiltration is the effect of air pressure difference. Warm air rises while cold air falls. The warm air within a building rises and air pressure at the base falls; this results in air coming in through doors, windows and leakage points. Air permeability testing is a legal requirement for constructions in Strand-on-the-Green. This way, they can have high energy performance, meet building regulations requirements and get signed off by building control. Buildings where businesses are conducted will not cause discomfort to employees and clients because they have the legal air permeability rating. This increases the company’s productivity and lowers heating and cooling expenses.
Air tightness testing has been a compulsory part of the Building Regulations for new dwellings, renovations and commercial projects since the revision of Document L in 2006. Other names for air tightness are air permeability rate or leakage rate. Air leakage can happen via holes and splits in the texture of the building envelope (divider/rooftop sections, service penetrations, etc), which may not be obvious. It is compulsory for all commercial buildings with a gross area greater than 500m2 and a representative selection of domestic buildings to undergo air pressure test, as stipulated by Part L of the Building Regulations. The highest air permeability target set is 10m3/h/m2 but your building might need a much lower one. Air permeability is key in the following areas: i. A construction’s energy performance, ii. CO2 emission targets iii. Building Regulations Part L standards
We can provide you all that you need to serve all your Part L and Part F requirements. We deliver quality air permeability and extract fan flow rate testing, and also recommend skilled experts who will handle your water calculations, SAP calculations and Energy Performance Certificates.
Approved Document F of the Building Regulations requires that all mechanical extract fans in new dwellings be subjected to a flow rate test. The Building Control Body (BCB) has to see the results of the test as part of its sign-off procedure. You can test, document and report the test of your building’s extractor fans in three ways. Using a vane anemometer, our testing procedure follows Method 3 – The minimum benchmark method.
Here are the descriptions of the ways air permeability can be tested: Level One: Testing for the air pressure of single buildings and smaller non-dwellings of 4000m3 gross envelope volume and below, a single blower door fan is used. Air tightness testing for dwellings more than 4000m3, except big phased handover/zonal and high rise (LCHR) constructions is done. Air tightness testing for phased, zonal handover and LCHR constructions is done.
Air pressure testing, involves the calculation of air escaping through openings in a building. The result of the air leakage test is expressed as a quantity of air leakage (mm3 per hour) per square metre of building envelope. Air tightness testing is required for new builds. The carbon discharge requirement for all buildings reduces the air permeability rate target. 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. Air tightness testing is required by Building Regulations. The results of air permeability rate should not exceed 10m3/h/m2. A building will usually have to achieve a lower rate to meet the SAP or SBEM assessment. The design-stage SAP or SBEM assessment of a construction records its required air permeability rate. Air leakage causes heat loss, increased energy bills, greater CO2 emissions, and an uncomfortable atmosphere for inhabitants due to draughts.
We provide smoke shaft tests to make sure it is air tight enough to let the automatic opening ventilation work optimally when it’s installed and commissioned. 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. With the right air permeability rate, the vents can operate at their best. We aim for the air permeability rate set by the vent manufacturers. An air pressure test is taken for the smoke shaft by installing a fan inside. 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.
The requirement to build more highly insulated and air tight buildings means that it is increasingly more important to ensure buildings are not only adequately ventilated but the ventilation system is suitable and commissioned correctly to ensure its effective operation. We evaluate extraction rates. It is important to ensure the ventilation strategy is working effectively. This helps to remove pollutants from the air and control excess humidity, particularly in rooms such as bathrooms and kitchens. Part F states that all new constructions must have intermittent extractor fans whose air flow rates will be calculated and the results given to Building Control before the building work is finished.
Air tightness tests calculate the level of air leakage a building has and if it is excessive. When air leakage is reduced in a building, the occupants will not experience discomfort and the energy performance will increase.
Holes and spaces in a building’s fabric might be hidden by the internal building finishes, making them hard to find. To ensure that the air tightness of a building is optimal, gaps and spaces in the building have to be found and measured.
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. We recommend that all buildings be tested as those that aren’t are penalised.
Our test engineers require the drawings (plans and elevations) and target air permeability requirements of your building before taking the test. 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. In preparing the site to create an air-tight environment:
We conduct building envelope calculations prior to the test. A building envelope is the boundary between the conditioned and unconditioned environment of a building. The measurement is obtained from the construction drawings, and put in our calculations to conduct the test.
Approved Document L1A Conservation of Fuel and Power in New Dwellings (2010) defines air permeability as “air leakage rate per hour per square metre of envelope area at the test reference pressure differential of 50 pascals (50n/m2)” and envelope area as “the total area of all floors, walls and ceilings bordering the internal volume that is the subject of the pressure test. This includes walls and floors below external ground level. Overall internal dimensions are used to calculate this envelope area and no subtractions are made for the area of the junctions of internal walls, floors and ceilings with exterior walls, floors and ceilings.”
Although hardly used as a major deciding factor for calculation or design, air exchange rate is vital in ventilation design. To calculate ventilation rates for domestic buildings, the area and number of people living in the building are considered.
It is important to make sure the roof area and ground floor area of a building are equal. A cold roof has its insulation at the ceiling level, with space between the insulation and rafters.
In a warm roof, an air barrier is inside the insulation which runs on the pitched roof rafters. The envelope area, found at the insulation’s warm side, is the separator between the conditioned internal aspect and the unconditioned.
Check weather conditions (wind speed, temperature, barometric pressure); Connect a fan (or fans) to an aperture in the building envelope (e.g. door). 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. Increase the speed of the fan slowly till it gets to 55-60Pa. Record how the air pressure differs at each fan speed.
Our competent engineers note the points of air leakage, examine the test data and send test results to the customer in a technical report. If the test fails, we inform clients on what to do about it. Testing for Air Tightness & Meeting Part L Standards
When a building has the right kind of ventilation (mechanical, natural or a combination of both) and has a low permeability rate, the advantages to the occupants are numerous. Some of them are: Lower energy costs and need for heating appliances due to a higher level of heat retention. The ventilation system will operate optimally Your building will have less mould since moisture cannot escape into holes and cavities. You won’t experience much discomfort because there will be fewer draughts. From the smallest to biggest building or development, we adhere to Building Regulations Part L and Building Standards. We provide air tightness testing, consultancy, design reviews and support services on all buildings, both dwellings and non-dwellings in Strand-on-the-Green. We also provide cost-effective, local service that complies with all relevant Building Standards.
Building Regulation Part L1A 2010 stipulates that all new buildings must have low air permeability. Less fuel and power are consumed by buildings. Part L1A has demanded that all new dwellings be tested for air leaks in line with other regulations.
The Air Tightness Testing & Measurement Association (ATTMA) provides the technical standard to be followed for the testing of dwellings in the UK as set out in Building Regulations and other documents. 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. Those exceptions only occur when there are two or more dwellings in a development. Three units of a dwelling type or 50% of all examples of that dwelling type should be tested. Where there are only one or two new buildings, add an assumed value of 15m3/h/m2 to the DET/TER measurements; an air tightness test may not need to be carried out. Find out from your SAP assessor if this is applicable to you. The required process for testing buildings for air tightness has been declared in ATTMA TSL1 for occupied buildings and ATTMA TSL2 for unoccupied ones. Air tightness tests are to be carried out on all residential developments (all the buildings or a selected group) and all certain Non-Dwellings. Non-dwellings with a typical floor area less than 500m2 may be exempt. Where testing is not carried out, an assessed air permeability of 15 m3/h/m2 must be used in calculations.
In January 2015, the ATTMA Scheme for Competent Air Tightness Testing Firms and Their Testers (The ATTMA Scheme) was launched. It is an industry competence scheme authorised by the government and specified in Technical Standard L1 & L2. It mirrors the operation standards and skill requirements set by the National Occupation Standard (NOS) and the Minimum Technical Competence (MTC) document.
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.
We analyse our tests and results for any divergence from the standards required and check the air pressure rate against target rate. That way, our results are expressed in line with test standards. We will ensure the report correctly identifies the tester, customer, building and its address. Where applicable, we will identify pass or failure of your building and provide recommendations for any remedial action or improvement to the building if any further testing 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.
