Air tightness testing, otherwise called air pressure testing or air leakage testing, is the measurement of the outflow of air from a building’s fabric. 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. We register our air tightness certificates with the Air Tightness Testing and Measurement Association (ATTMA), an organisation that encourages proper air leakage applications and promotes quality air tightness screening. AF Acoustics, a licensed air tightness testing company, is available to provide testing services at your request. Our address is Plashet. You can also call or email us for any of these services:
Our air leakage test certificate is approved by ATTMA and is an indication that a building has been signed off by building control. If you want specialist air pressure testing services in Plashet, AF Acoustics’ tightness testing services will
We deliver professional value for money service to the highest standards.
Air tightness testing is carried out to determine the volume of air escaping from holes in a building fabric. It is sometimes referred to as air leakage testing or air pressure testing. Air leakage should not be confused with ventilation. Also called draughts or infiltration, air leakage is unrestrained movement of air through holes in a building fabric, while ventilation is the restrained and planned movement of air. Air tightness testing evaluates the complete air leakage a building has in every gap available. The air leakage is known as uncontrolled ventilation. Once too much air escapes, heat reduction occurs, causing the temperature of the building to drop to a level that isn’t comfortable for those residing in it. Because the government is striving to scale back carbon dioxide discharge from new buildings, building rules now focuses on reducing air loss from the building envelope. This helps reduce 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. A building that is air tight A building that is air tight is more economical and ensures less drafts ALS energy efficient.
This occurs when openings in a building lead to excess air flow into and out of the building. When the circulation of air is properly monitored and bridled, ventilation has occurred. Another name for air leakage is infiltration. Because of the nature of air leakage, excessive air infiltration might occur in a building when the weather is windy and chilly. This results in loss of warmth and an unpleasant cold draughts. Testing for air leakage plays a primary role in determining the energy efficiency of a building. It is an important procedure that measures the air tightness level to ensure that the regulatory standards have been attained and the building’s energy calculations have been properly accomplished. All commercial buildings over 500m² and new buildings in England and Wales are mandated to test for air tightness and permeability, according to the 2006 Building Regulations.
When air escapes uncontrollably from a building, heat reduction occurs. During windy or cold weather, the infiltration of uncontrolled air through cracks in a building envelope occurs, leading to heat reduction. It doesn’t stop there. Warm, damp air within the building escapes the gaps in its envelope. When moist air hits a cooler surface within a wall structure, water vapour in the air can condense and collect inside these spaces. Moisture can then be absorbed in building materials and cause serious defects. Wooden sheathing or overlay becomes wet, making it weak.
The building becomes structurally damaged as time goes on.
Other effects of air leakage are:
The most effective method of lessening the damage caused by moisture is to control the flow 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. Fossil fuel is burnt to heat up a building. This leads to a discharge of carbon dioxide which increases global warming. The reduction of air leakage leads to lower heat loss and quantity of heat generated in a building. Poor degrees of ventilation and high levels of uncontrolled air leakage encourage mould growth and excessive moisture. This could potentially cause medical issues. To “Construct tight, ventilate right” is the best practice. The result of uncontrollable air moving into the building fabric could be health problems and costly repairs.
It is best practice to complete an air tightness test early on and then again at the final stage. The results of the test are used in SAP and SBEM calculations, and can influence a building’s overall energy rating. Large residential areas do not need each building to be tested. Instead, different types of dwellings are tested. With selective testing, you get a penalty of +2m3/h/m2. Houses that have a target score of 5m3/h/m2 must get a lower score of 3.
If your building has not been pressure tested, its assessed air permeability would be the average score of buildings like yours in the area +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.
Business owners and home owners in Plashet have been helped by AF Acoustics air tightness testing. Because of the following guarantees of working with us, we are highly endorsed by our clients.
Due to years of experience in conducting air tightness testing in different kinds of buildings in Plashet, we have the skills to meet your needs no matter the type or size of your property. Our air tightness experts are certified, well-mannered and competent. They’re trained to deliver a quality service, working as an extension of your project. If you need knowledgeable and trustworthy air leakage experts who can provide exemplary results, AF Acoustics is the team you need in Plashet.
We are registered with the Air Tightness Testing and Measurement Association (ATTMA), an organisation that is centred on technical excellence in all air leakage measurement methods. ATTMA, the leading air leakage testing body in the UK, has recognised the quality of our services.
We want you to be able to access comprehensive air tightness testing in Plashet whenever you need it. We have responsive scheduling options. Schedule for your air leakage testing at your comfort. We won’t make you wait or make the process complicated.
Our customers are eager to get their test results. AF Acoustics, which provides reliable, competent services, strives to issue test certificates on the next day.
AF Acoustics fees are lower since we’re a company with low overheads. Our services are professional and we offer affordable prices in Plashet.
Regardless of the size, type, or complexity of your domestic or commercial building in Plashet, we can provide you with air tightness testing, carried out by an experienced and professional air tightness tester and issue you a certified ATTMA certificate. You can find out how much uncontrolled ventilation your building has by testing it for air leakages. The results are registered as The test results are described as m3/h/m2 – (m3 per hour) per square metre of building.
Air tightness testing is recommended by Approved Document L1A and L2A. Although your building is required to have a rating result of 10m3/h/m2, the actual result might have to be lower than that due to carbon emission requirements. You can find the required air permeability rate of your building in its design-stage SAP assessment or SBEM. Several problems are caused by uncontrolled ventilation. They are:
Warm air within a heated building rises and lowers the pressure at the building’s base to draw in air through the openings in the building fabric, leading to exfiltration or infiltration. Air permeability testing is a legal requirement for constructions in Plashet. 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. Heating and cooling expenses are also reduced and the environment is more productive.
Air tightness testing is a Building Regulations obligation for new buildings, commercial developments and revamped buildings. This was put into effect in 2006 after Document L was reappraised. Air tightness is also called air leakage rate or ‘air permeability’ rate. Although not always seen, air leakage can occur through any gap, space or crack in a building’s fabric. 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. The maximum air permeability rating allowed is 10m3/h/m2, but your building might need a lower rating ts. Air leakage is vital to a building’s energy efficiency and is needed to meet Building Regulations Part L and carbon emission standards.
We can provide you all that you need to serve all your Part L and Part F requirements. First, we provide extract fan flow rate and air leakage testing. Then we put you in contact with competent professional to work on your Energy Performance Certificates, SAP and water calculations.
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. AF Acoustics employs the minimum benchmark procedure (method 3), which involves using a vane anemometer.
Air Tightness Testing has different tiers, depending on how complex a building is and its size. Find them below: A single blower door fan is used for air tightness testing for single buildings and smaller non-dwellings not more than 4000m3. Air tightness testing for dwellings more than 4000m3, except big phased handover/zonal and high rise (LCHR) constructions is done. Level 3: Air Pressure Testing for LCHR buildings, phased and zonal handover buildings is carried out.
An air leakage test is a test to determine the level of uncontrolled air flow through gaps or cracks in the fabric of a building. The result is written as m3 per hour per square metre of building. Air pressure testing is compulsory, according to Approved Document L1A. Your building may need a lower rate to meet the CO2 discharge target. You can find the required air permeability rate of your building in its design-stage SAP assessment SBEM. 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 written as m3/h/m2 – (m3 per hour) per square metre of building envelope. Document L2A of Building Regulations declares air leakage testing to be mandatory. The results of air permeability rate should not exceed 10m3/h/m2. Your building may need a lower air permeability rate to meet the SAP or SBEM assessment. To get your building’s required air permeability rate, check its design-stage SAP or SBEM assessment. An excessive amount of air leakage leads to greater energy expenses, heat reduction, carbon dioxide discharge and draughts.
We undertake smoke shaft integrity testing to confirm that the shaft is sufficiently air tight in order to allow the automatic opening ventilation to perform as required when it is fitted and commissioned. Smoke needs to be cleared out in the event of a fire. The automatic opening ventilation is a vital aspect of the fire strategy for high rise buildings. 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. To ensure that automatic opening ventilations work properly, their manufacturers have placed an air permeability target for them which we work towards. Fans are placed in the smoke shaft to conduct an air tightness test. 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. Extract fans are tested by us. This is done to meet the Building Regulations standard. Make sure the ventilation system is efficient, expels pollutants and odours, and reduces humidity, especially in kitchens and bathrooms. Part F Building Regulations also require standard intermittent extractor fans in new buildings (such as bathroom and kitchen extractors) to have their air flow rates measured on site and the results submitted to the building control body before completion.
An air tightness test measures the extent of air leakage in a building. If the rate of air pressure is good, the energy performance of a building will be high and the inhabitants will be comfortable.
External claddings and the internal building finishes might obscure a gap in the building fabric. This makes it hard to notice and can results to potential air leakage. 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 policies of building developments, the lowest number of domestic buildings developers have to test in an area is 20%. However, this depends on the quantity of different house kinds to ensure there is a regular sample throughout the survey. We recommend that all dwellings be tested, as there is a penalty for developments that are not tested.
Our test engineers require the drawings (plans and elevations) and target air permeability requirements of your building before taking the test. The duration of air pressure testing is 30 to 60 minutes in most cases and the wind speed should not be more than 6m/s. Test engineers need the drawings and air permeability details from clients so that they can know the size of the building envelope and other information before arriving at the building. To prepare the site for the test, do the following:
We take the building envelope calculations before the test. The building envelope is the physical separator between the indoors and outdoors. The measurement is obtained from the construction drawings, and put in our calculations to conduct the test.
Air permeability, according to Approved Document L1A (2010), has to do with “air leakage rate per hour per square metre of envelope area at the test reference pressure differential of 50 pascals (50n/m2)”. The building’s envelope area has to do with the total area of all the floors, walls, and ceilings bordering the internal environment, including those below external ground level. These include shared walls, floors and ceilings in storey buildings. Internal dimensions are used to measure the envelope area.
Air change rates are often used as rules of thumb in ventilation design but they are seldom used as the actual basis of design or a calculation. 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 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 is a roof system where the insulation is fixed along the rafters with an air barrier inside the insulation. In the warm part of the insulation, is the barrier between the conditioned and unconditioned space.
Check weather conditions (wind speed, temperature, barometric pressure); Fix a fan to an aperture, usually the door, in the building. Set up testing equipment. Using the fan, measure the air flow volume, from the building fabric. Gradually increase the fan speed from 20-25 Pa to a maximum of 55-60Pa. Note the difference in air pressure in several parts of the building at each fan speed.
We analyse the recorded air tightness test data and present the results to the client in a technical report. In the event of test failure, we advise the client on appropriate mitigation measures. Our expert knowledge will help in highlighting the areas of air leakage. Air Tightness Testing and Compliance
Making sure your building is air tight and has adequate ventilation, be it natural, mechanical, or a combination of the two, will aid your comfort. Find below the benefits: Lower heating bills due to less heat loss, with potentially smaller requirements for heating and cooling equipment capacities Better ventilation system Less mould will be trapped in the building fabric as a result of less moisture. Infiltration of air is reduced and the inhabitants are more comfortable. From a single dwelling to the largest commercial development, we offer stress-free compliance measurements to Part L Building Regulations and Building Standards. We render cost-effective services that include air leakage tests, design reappraisal, consultancy and support services for dwellings and non-dwellings in Plashet.
Building Regulation Part L1A 2010 stipulates that all new buildings must have low air permeability. The regulation is focused on the conservation of fuel and power usage. The dwelling should be tested for air permeability in line with existing building standards, as stipulated by Approved Document Part L1A.
Certain technical standards are to be employed during air pressure test in the UK, as specified by ATTMA, building regulations and other documents. This Technical Standard provides detailed guidance and clarification of 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”, in order to ensure consistency by testing companies.
Approved document L1A has made it compulsory for all new buildings to be tested for air leaks. 50% or 3 units of each dwelling type should undergo an air leakage test in the case of an area with two or more dwellings. For developments where no more than two dwellings are constructed, it may be possible to avoid the need for any pressure testing by using an assumed value of 15m3/h/m2 within the DER/TER calculations. An SAP assessor can decide which buildings can use the assumed value successfully. ATTMA TSL1 and ATTMA TSL2 prescribe methods for testing occupied and unoccupied buildings. Non-Dwellings and residential buildings are required to test for air leakage. A building might not have to undertake the air leakage test if its floor space is less than 500m2 or its DET calculations have an air permeability rate of 15 m3/h/m2 added to it.
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. Its basis is the National Occupation Standard (NOS) and Minimum Technical Competence (MTC) documents standard for testing and essentials for testing knowledge.
Authorised companies, who test buildings of different types, sizes and complexities, give air tightness reports. Extraction fans will be sealed temporarily; the results of the test are recorded in a short report. The organisation makes sure the report meets the company and government’s requirements.
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. The identity of the customer, tester, building and address are correctly written in our report. We will state if your building has passed or failed the test and give advice on the actions you need to take if another test is needed.
Send us your building design air permeability target and crosscheck the list below before we get to the site.
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.
