Air tightness testing determines the quantity of air coming out of cracks in a building. It is also known as air permeability testing or air leakage testing. In 2006, Approved Document L was reviewed and building regulations for air permeability became more stringent. The test is presently a requirement for new buildings and reconstructions.
Air leakage occurs through any opening in the building envelope and can affect a building’s energy performance, this has been addressed by changes to the building regulations. 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 dedicated and accredited air leakage testing service providers in Bexley and we are available to provide you with testing services whenever required. We also provide Part F mechanical extract fan flow rate testing, assessments and consultancy services.
As registered members of the Air Tightness Testing and Measurement Association, our air leakage test certificate is accepted as evidence for Building Regulations sign-off. If you want specialist air pressure testing services in Bexley, AF Acoustics’ tightness testing services will
AF Acoustics provides services that are cost effective and of high standard.
When a building is assessed during an air tightness test; the internal thermal envelope of the building is examined for leakages and the quantity of air passing through it. Air tightness testing is also known as air pressure testing or air leakage testing. Air leakage is the uncontrolled flow of air through gaps and cracks in the fabric (often referred to as infiltration or draughts) and not ventilation, which is the controlled flow of air in and out of the building. Air tightness testing evaluates the complete air leakage a building has in every gap available. The air leakage is known as uncontrolled ventilation. An excessive amount of uncontrolled air loss results in heat reduction, making the residents uncomfortable. As Government strives to reduce CO2 emissions from new buildings, building regulations now place greater emphasis on reducing air leakage from the building envelope. This reduces fuel consumption and CO2 emissions. Air tightness testing is a crucial activity that
The building regulations have made air tightness part of the building’s design from the beginning of the construction. This ensures that the fabric of a building is air tight. When the building fabric is properly constructed to reduce air loss, the building is economical, and energy efficient.
Air leakage is where air enters and leaves a building uncontrollably through cracks and holes in the building fabric. Also called infiltration, it differs from ventilation which is the regular, planned and restrained flow of air into a building. 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. In England and Wales, air tightness testing has been obligatory since 2006. All new dwellings and non-dwellings over 500m² are to be tested for air permeability.
Air leakage leads to a reduction in heat. During windy weather, cold air infiltrates a building through the openings in its fabric. This results in heat loss. Movement of moist air into cavities in other parts of the building also occur. This process is called exfiltration. 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. Wet wooden framing or sheathing can rot and break down, diminishing its strength.
These problems will eventually cause structural harm to the building.
Other damages that can occur are cold homes which make occupants uncomforta-ble, increase in heating bills to make the internal temperature warmer, and more carbon dioxide discharge since additional heat is required.
Successfully managing the movement of air into and outside the building will limit the damaging effects of moisture. Air leakage and vapour diffusion are minimised when barriers are installed. Passive or active ventilation is required to reduce water vapour, moisture odour and pollutants.
Climate change caused by carbon dioxide emission is an environmental hazard that government is trying to curb. Energy performance and air tightness is a key part of this plan. Home heating involves burning up fossil fuel which produces carbon dioxide and aids global warming. A reduction in air leakage lessens the heat needed to keep a building warm. Uncontrolled air leakage also results in health problems. Coupled with poor air circulation, it leads to the growth of mould and mildew. The best advice is to “Construct tightly, ventilate properly”. Air leakage causes infiltration of moisture into the building envelope, leading to health issues and high repair costs.
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 test results are part of SBEM and SAP calculations, therefore they influence the total energy ratings of new buildings. Large residential areas do not need each building to be tested. Instead, different types of dwellings are tested. 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 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 Bexley have been helped by AF Acoustics air tightness testing. We come highly recommended by our clients because of the following guarantees.
Our vast experience in serving a variety of clients in Bexley guarantees we have the expertise to satisfy your needs regardless your unique circumstances, type or size of property. We’ll work with you to carry out our tests and consultations at times that are convenient to you, delivering an exceptional quality, convenient service. If you need knowledgeable and trustworthy air leakage experts who can provide exemplary results, AF Acoustics is the team you need in Bexley.
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 Bexley whenever you need it. We have responsive scheduling options. Schedule for your air leakage testing at your comfort. We guarantee that there will be no delays or difficulties.
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 Bexley.
Regardless of the size, type, or complexity of your domestic or commercial building in Bexley, 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. The best way to determine how much air seeps through a building’s fabric is through air permeability testing. 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. 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 Bexley. Buildings where businesses are conducted will not cause discomfort to employees and clients because they have the legal air permeability rating. In addition, you get lower heating and cooling costs. A comfortable environment results in a higher productivity rate.
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. Other names for air tightness are air permeability rate or leakage rate. Although not always seen, air leakage can occur through any gap, space or crack in a building’s fabric. 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. To comply with Part L the measured air permeability minimum requirement is 10m3/h/m2 but usually your air permeability target will be much lower. Air tightness is important for meeting the Building Regulations Part L standards, exceeding requirements for low carbon buildings, and overall energy efficiency.
We will ensure that you exceed all the Parts L and F standards. Not only will we conduct your air tightness test and extract fan flow rate test, we will also recommend experts who can handle your SAP calculations, water calculations and Energy Performance Certificates satisfactorily.
Get the mechanical extract fans tested for flow rate. This is what Building Regulations Approved Document F requires. Your building won’t be signed off until Building Control Body (BCB) has been presented the results of the test. There are three alternative methods which can be followed to test, record and report the testing of extractor fans. AF Acoustics test process is the third method. It uses a vane anemometer and is called the minimum benchmark method.
There are different levels of air tightness testing established from the size and complexity of a building. An overview of each is provided below: 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. Second Level – Testing is done for building 4000m3 and higher, typically simple and complex dwellings. High rise and phased handover buildings are not part of this test. Level Three: At this level, tests for the air pressure of high rise (LCHR) buildings and phased handover/zonal buildings.
Air pressure testing, involves the calculation of air escaping through openings in a building. The result is expressed as a quantity in the form of m3 per hour, per square metre of building fabric. Air tightness testing is required for new builds. A lower air permeability rate might be needed due to carbon emission requirements. The required air permeability rate for a dwelling can be found on the design-stage SAP report for that dwelling. Too much air leakage leads to heat loss which can lead to draughts and higher energy bills.
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/h/m2 – (m3 per hour) per square metre of building envelope. Part L2A of Building Regulations has demanded that such tests be conducted. The test results have a limit; they shouldn’t be higher than 10m3/h/m2. A building will usually have to achieve a lower rate to meet the SAP or SBEM assessment. You can find the required air permeability rate of your building in 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. Automatic opening vents are crucial during fire emergencies in storey buildings, as they clear out smoke from the buildings. For the fans and vents to perform as required, the shaft itself must be sufficiently air tight so as to create the pressure difference to draw smoke out of the building and protect the occupants. 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. The intended openings of the shaft (i.e. extract point and openings for ventilation grilles on each floor) are sealed off for the test so that the integrity of the shaft itself can be determined. Smoke shaft tests occur before installing and commissioning automatic opening ventilation.
Buildings that are well insulated and air tight are the standard for buildings. As a result, a high-quality ventilation system that is adequate and performs as required is vital. We evaluate extraction rates. 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. The air flow rates of all intermittent extractor fans, which are to be installed during the building process, are to be tested and the results submitted to the Building Control Body before work is completed.
When a building is checked for the quantity of air flowing through the gaps in the fabric, it has undergone an air tightness test. When air leakage is reduced in a building, the occupants will not experience discomfort and the energy performance will increase.
It is difficult to notice unwanted openings in a building envelope. They might be blocked by the internal finishes. The best solution to demonstrate a building’s air tightness level is to check for leakage paths in the building envelope.
With residential buildings in an area, new building regulations demand that a minimum of 20% be measured for air leakage. Consistent samples are determined by the quantity of the different types of houses present during the construction of the project. There is a penalty for untested constructions. Therefore, we suggest air leakage tests for all buildings.
The client needs to send our test engineers the drawings of the development (plans and elevations) and target air permeability requirements. This is to have the needed information for the building and to know the size of the building envelope before coming to the site. Air tightness testing lasts for 30 to 60 minutes and wind speed is not more than 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. The building envelope is the physical separator between the indoors and outdoors. The building envelope calculations are taken from the drawings and used for our air tightness testing.
Air permeability is measured as air leakage per hour per square metre of the building fabric at a pressure differential of 50 pascals (50n/m2). The air barrier envelope area is the total area of all the floors, walls and ceilings both above ground and underground. The internal dimensions of the building found in the drawings are used to calculate the envelope area and subtractions are not made from the areas of floors and ceilings with or without external walls or from the area of the junctions of internal walls.
Air changes per hour are crucial to ventilation design, but it is only occasionally used as the base for the design or calculation. To calculate ventilation rates for domestic buildings, the area and number of people living in the building are considered.
The area of the roof and ground floor should be the same. A cold roof has the insulation at the horizontal ceiling level and a large void or space between the insulation and the pitched roof rafters.
In a warm roof, an air barrier is inside the insulation which runs on the pitched roof rafters. The envelope area is the boundary between the internal environment and external environment (adjacent buildings), and can be found on the insulation’s warm part.
Check all weather conditions such as temperature, wind speed and barometric pressure. Connect a fan (or fans) to an aperture in the building envelope (e.g. door). Set up testing equipment. Using the fan, measure the air flow volume, from the building fabric. Gradually increase the speed of the fan to a maximum of 55-60Pa. At each fan speed, note the differences in air pressure in all the parts of the building.
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. Air Tightness Testing and Compliance
An airtight building has several positive impacts when combined with an appropriate ventilation system (whether natural, mechanical, or hybrid): Lower heating bills due to less heat loss, with potentially smaller requirements for heating and cooling equipment capacities Better performing ventilation system Less mould will be trapped in the building fabric as a result of less moisture. You won’t experience much discomfort because there will be fewer draughts. Our air leakage tests are conducted according to building regulations and targets, whether we’re testing a small dwelling or big commercial development. Our services include: air pressure testing, support services, re-examining designs and consultancy for all buildings in Bexley. We are cost effective and adhere to all building regulations.
All new buildings, residential or commercial, must be air tight, according to Approved Document Part L1A of Building Regulations (2010). This regulation was put in place to conserve fuel and power. Part L1A has demanded that all new dwellings be tested for air leaks in line with other regulations.
There are technical standards for air tightness test of buildings in the UK detailed by Air Tightness Test and Measurement Association (ATTMA). The technical standards give details regarding the following: 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”. That way, testing companies use the same method.
Test for air permeability must be conducted on your new constructions. This is stated in Approved Document L1A. For developments of two or more dwellings, an air leakage test should be carried out on the three units of each dwelling type; or 50% of all instances of that dwelling type. 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. Your SAP assessor will be able to confirm if this is the case for your dwelling. ATTMA TSL1 and ATTMA TSL2 prescribe methods for testing occupied and unoccupied buildings. Both residential areas and many non-Dwellings are to take the air leakage test. 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.
ATTMA has a competent scheme for air leakage testing firms which determines their level of competence. The scheme, which was launched in January 2015, is recognised by the government and noted in the building regulations. The scheme echoes the conditions of the Minimum Technical Competence (MTC) and the National Occupation Standard (NOS) documents.
Test reports are issued by registered and licensed air tightness companies who test buildings of different sizes and complexities. Extraction fans will be sealed temporarily; the results of the test are recorded in a short report. This is done according to the testing organisation’s procedures and Building Regulation standards.
Our test and subsequent results are conducted and written to meet standard requirements, highlight any deviation from the standards and crosscheck air pressure values against target values. We will ensure the report correctly identifies the tester, customer, building and its address. If a building fails the test, we provide remedial suggestions before a retest is carried out.
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.
