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. 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.
Changes to building regulations have addressed air leaks which affect a building’s energy efficiency. Our certificates for air tightness testing are registered with the Air Tightness Testing and Measurement Association (ATTMA), a professional body that focuses on high quality air tightness testing and air permeability applications. We are a dedicated and approved air leakage testing service in Limehouse and we can provide air permeability measurement whenever you require. We also provide Part F mechanical extract fan flow rate testing, assessments and consultancy services.
Because we are ATTMA members, any air tightness certificate we issue shows that the construction has met building regulation standards. 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 services provide great value for money at high standards.
Air tightness testing is a method of measuring the extent to which air is lost through leaks in the building fabric. It is sometimes referred to as air leakage testing or air pressure testing. While the normal restrained movement of air all through a building is called ventilation, the unchecked movement of air through cracks and gaps in a building is air leakage; also known as draught or infiltration. Air tightness testing is done to calculate the total quantity of air that escapes through cracks in the building. Such air leakage is called uncontrolled ventilation (draughts). When too much air leaks through a building’s fabric, heat loss occurs, making the occupants uncomfortable. Air leakage from buildings causes heat loss, more energy is then used to keep the building warm, this is a cause of excess CO2 emissions. This has resulted in regulations which are centred on decreasing air leaks from the building fabric, therefore lowering CO2 emissions. Air tightness testing is vital in determining the energy efficiency of a new building, air leakage and the build quality. Most building designs take air pressure into account at the beginning of construction in order to have an air-tight envelope and measure up to the required standards. Incorporating this at the beginning of the construction process makes the development more cost effective and energy efficient.
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. 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 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 2006, air tightness of newly constructed buildings and non-dwellings with a floor area over 500m² became compulsory in England and Wales.
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. As cold seeps inside, warm moist air escapes through the cracks and gaps in the building. Some of it settles within the building’s fabric. 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.
Over the years, these problems can damage the building’s structure.
Other effects of air leakage are:
Successfully managing the movement of air into and outside the building will limit the damaging effects of moisture. An adequately installed air barrier reduces air leakage and condensation of water vapour on inner wall layers. Correct ventilation is important, whether it is passive or active, to remove water vapour, unwanted 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. Heating buildings contribute to global warming and CO2 emissions, since fossil fuels are used to create heat. 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. 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 dictates that you complete an air tightness test early in the build process, and then again after the construction process is completed; although not all builds have the first test phase. The test results are part of SBEM and SAP calculations, therefore they influence the total energy ratings of new buildings. 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. Selective testing has a penalty of +2m3/h/m2. If target score is 5m3/h/m2, air tightness test score will have to be 3m3/h/m2.
If the building has not been tested for air tightness, assessed air permeability rate is the average result of similar buildings in the area +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 Limehouse have been helped by AF Acoustics air tightness testing. We come highly recommended by our clients because of the following guarantees.
Having served many clients in Limehouse, we have the expertise to work on any type or size of building. 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. Our personnel will use their expertise to provide lasting solutions. Contact AF Acoustics in Limehouse –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 Limehouse at anytime. We offer responsive scheduling options. You can schedule for air tightness testing at your convenience. We guarantee no delays or complications regarding scheduling.
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 Limehouse.
We conduct air permeability tests on residential and commercial buildings of all sizes and types. After the test, an ATTMA certificate is given to you. An air leakage test is used to determine the level of uncontrolled air flow through gaps or cracks in the fabric of a building. The results are written as The test results are described as m3/h/m2 – (m3 per hour) per square metre. of a building envelope.
Air leakage testing is required by Approved Document L1A and L2A. The maximum air permeability rate is 10m3/h/m2. The carbon discharge requirement for all buildings reduces the air permeability rate target. This target can be found in a building’s design-stage SAP assessment or 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. 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 Limehouse. For your commercial building, air tightness testing will ensure your staff and clients are in a comfortable environment. Heating and cooling expenses are also reduced and the environment is more productive.
In 2006, Approved Document L was reviewed and building regulations for air permeability became tighter. The air tightness test is presently a requirement for new buildings and reconstructions. 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 non-domestic buildings which have a gross floor area greater than 500m2, be subject to mandatory air permeability tests. For domestic dwellings, a sample of houses (in a development) must 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.
All your Part L and Part F testing requirements can be met by us. 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.
According to Part F, it is compulsory for a flow rate test to be conducted on all mechanical extract fans of new buildings. Building Control Body (BCB) has made a presentation of evidence of the test a compulsory aspect of a building’s sign-off process. You can test, document and report the test of your building’s extractor fans in three ways. We use a vane anemometer, which is the third method called the minimum benchmark method, to conduct extract fan flow rate tests.
Here are the descriptions of the ways air permeability can be tested: Level 1: Air pressure testing for single dwellings and other smaller non-dwellings up to 4000 m³ gross envelope volume, typically tested with a single blower door fan. 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. Level 3: Air Pressure Testing for LCHR buildings, phased and zonal handover buildings is carried out.
The measurement of air emitted by a building is tested to determine air permeability rating. 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. A lower air permeability rate might be needed due to carbon emission requirements. To get your building’s required air permeability rate, check its design-stage SAP assessment SBEM. Too much air leakage leads to heat loss which can lead to draughts and higher energy bills.
Air leakage testing is the measurement of uncontrolled ventilation from a building’s fabric. 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 maximum air permeability rate for a dwelling tested is 10m3/h/m2. In order to comply with the SAP assessment, it may be necessary to achieve a lower air permeability rate. The air permeability target can be found in a building’s design-stage SAP or SBEM assessment. Excess air leakage causes heat loss, greater carbon dioxide discharge and influx of cold air.
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. For the vents and fans to operate at the expected level, the smoke shaft must be air tight to create a difference in air pressure and give emergency services when needed. We work towards air permeability targets set by the automatic-opening ventilation manufacturers that allow their equipment to operate effectively. The shaft is tested for air permeability by using a fan that is fixed inside it. Then the openings are sealed off in all its parts so that the shaft can be thoroughly examined. This test is conducted before the automatic opening ventilation is fixed and commissioned.
The requirement for air tight buildings that are properly insulated has brought about the need for ventilation systems that are adequately installed and function at an optimal level. We test fan extraction rates. A building must have an optimal ventilation system to dispel humidity from bathrooms, kitchens and other rooms and extract odours and pollutants. We can also help you meet the Building Regulations targets. Another of such targets, as stated by Part F, is to have the standard intermittent extractor fans, like kitchen and bathroom extractors, in new constructions measured for air flow and results given to Building Control before the construction work is completed.
An air tightness test measures the extent of air leakage in a building. The air tightness of a building improves its energy efficiency and internal environment.
Causes of excess air leakage are often hard to detect. These openings might not be seen because of the internal finishes that have been fixed. The most acceptable approach to show that a building fabric is impermeable is to identify leakage paths within it.
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 buildings be tested as those that aren’t are penalised.
Our test engineers would like to see the drawings (plans and elevations) and design air permeability requirements of your building before taking the test. The test engineers would like to have the information needed for the test before coming to your development. Our air leakage test is done between 30 and 60 minutes, and the wind speed is a maximum of 6m/s. An air tight environment should be created in your building before the test to ensure optimal results. Do the following:
We take the building envelope calculations before the test. A building envelope is the boundary between the conditioned and unconditioned environment of a building. The calculations are taken from the drawings. These are then incorporated into our calculations when we air test the property.
It is defined as air leakage rate per hour per square metre of envelope area at the test reference pressure differential of 50 pascals (50n/m2). The envelope area, or measured part of the building, is 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.
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.
This is essential to determine if the roof area is the same as the ground floor area. A cold roof has its insulation at the ceiling level, with space between the insulation and rafters.
A warm roof is a roof system where the insulation is fixed along the rafters with an air barrier inside 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.
To get the building ready, close and secure all internal doors, windows, Temporarily seal vents and smoke vents. Also fill drainage traps.
Evaluate the weather (barometric pressure, wind speed and temperature) Connect a fan to an aperture within the construction envelope. For example, the 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. Slowly raise the fan speed from 20-25Pa to 55-60Pa. Record pressure differences across the building 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
The positive effects of an air tight building with efficient ventilation (natural, mechanical or a combination) cannot be underestimated. Here they are: The occupants will pay less for heat because less heat is lost and they won’t need equipment with high heating capacities. A functional ventilation system 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. Not only do we provide services that meet building regulation targets, when you employ our services, you’ll save money and spend less in the long run. We test for air permeability, provide consultancy services and support services and review the designs of all buildings, whether domestic or commercial, large or small.
When constructing a new building, it should be built air tight, as stated by Building Regulations – Approved Document L1A. The regulation helps to reduce the use of fuel and power. Part L1A further makes it obligatory for new buildings to be tested for air permeability in line with existing building standards.
There are technical standards for air tightness test of buildings in the UK detailed by Air Tightness Test and Measurement Association (ATTMA). 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”.
If you are constructing a dwelling the Approved Document L1A states that you must perform an air pressure test. 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. 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. Your SAP assessor will be able to confirm if this is the case for your dwelling. 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 leakage testing is required on all residential developments (this may be a sample of units) and 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.
An industry-wide competence scheme endorsed by the government is carried out by the ATTMA. It was launched in January 2015 as stipulated in the Technical Standard L1 and L2. It mirrors the operation standards and skill requirements set by the National Occupation Standard (NOS) and the Minimum Technical Competence (MTC) document.
Air tightness reports are issued by accredited firms that carry out air permeability tests on buildings of different sizes or complexities. First, extraction fans are closed. Then, the details and results of the tests are written down in a 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.
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 Permeability Pathway Checklist – Use this checklist to make sure you are ready for the test. Ask yourself, “Have I sealed any visible opening?” Check the following appliances.
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.
