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.
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 Air Tightness Testing certificates are registered with Air Tightness Testing and Measurement Association (ATTMA), a professional association dedicated to promoting technical excellence in all air tightness testing and air leakage measurement applications. We are dedicated and accredited air leakage testing service providers in Walthamstow and we are available to provide you with testing services whenever required. 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. We provide air leakage testing in a professional manner by explaining the testing procedures and highlighting leakage areas in the building fabric. We also suggest long-term remedies based on the results of the tests. We deliver professional value for money service to the highest standards.
Air tightness testing involves calculating the quantity of air which escapes through holes in the building fabric. It is sometimes referred to as air leakage testing or air pressure testing. Air leakage, also known as infiltration or draught, allows air to pass through unwanted leaks in a building; unlike ventilation where the air inside and outside of a building and its flow from one end to the other is controlled. Air leakage is uncontrolled ventilation. Air tightness testing is the approved method for gauging the entire air that has leaked through a building fabric. 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. As Government strives to reduce CO2 emissions from new buildings, building regulations now place greater emphasis on reducing air leakage from the building envelope. This reduces fuel consumption and CO2 emissions. Air tightness testing is vital in determining the energy efficiency of a new building, air leakage and the build quality. Building plans will often consider air tightness at the beginning stages of development so as to measure up to stricter building standards. When the building fabric is properly constructed to reduce air loss, the building is economical, and energy efficient.
This occurs when openings in a building lead to excess air flow into and out of the building. Also known as infiltration, it is different from ventilation, which is air that enters a building in a controlled manner. 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. In England and Wales, air tightness testing has been mandatory since 2006 for all new builds and non-dwellings with a floor area over 500m².
Air leakage leads to a reduction in heat. During windy or cold weather, the infiltration of uncontrolled air through cracks in a building envelope occurs, leading to heat reduction. The infiltration of chilly air causes exfiltration, making warm air within the building escape through the spaces in other parts of the building. 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. There could be a decrease in the toughness and solidity of wet wooden covering due to rot.
Over the years, these problems can damage the building’s structure.
Other impacts include:
The key to minimising the damage potential of moisture is effectively managing the flow of air into and out of the building. A properly installed air barrier minimises air leakage, which, in turn, minimises the potential for water vapour to condense on vulnerable wall structures. Proper ventilation, whether active or passive, is critical in expelling undesirable damp scents, water vapour and polluting substances.
The energy performance of a building is determined by how air tight it is. Energy performance affects CO2 released from buildings. As a result, air tightness testing is a method government has devised to regulate climate change. Environmental change caused by carbon dioxide emissions and global warming is partly aided by the burning of fossil fuels to generate heat. When air leakage is controlled, heat loss and energy used by the heating system are reduced. Individuals living in buildings with high levels of air leakage may have medical problems. Houses. Low ventilation and uncontrolled air leaks result in mould growth and moisture which can cause potential health issues. Best practice advice is to “Build tight, ventilate right”. High degrees of air leaks cause huge problems such as expensive remedial work on the building and medical problems.
It is best practice to conduct at least two air tightness testing procedures, one early in the build and another at the end. The results of the test are used in SAP and SBEM calculations, and can influence a building’s overall energy rating. Larger residential developments do not require testing to be completed on each individual property, instead, testing is undertaken on the different dwelling types within the development. 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.
buildings that have not been tested are assessed for air permeability based on similar dwellings’ test scores +2m3/h/m2 at 50 Pa. It’s better to test each property because selective testing does not give a realistic picture of individual buildings. Besides, air permeability rates are difficult to achieve for untested buildings in such areas due to the +2m3/h/m2 penalty.
Business owners and home owners in Walthamstow 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 Walthamstow guarantees we have the expertise to satisfy your needs regardless your unique circumstances, type or size of property. Our accredited air testing experts are polite and competent. They are trained to provide the service you need and fit around your project. If you need knowledgeable and trustworthy air leakage experts who can provide exemplary results, AF Acoustics is the team you need in Walthamstow.
AF Acoustics is a member of ATTMA, an association of specialists that concentrates on promoting the best air tightness measurements and air permeability testing techniques. It is the leading air permeability testing body in the UK and has recognised our competence and services.
We would like to give your building in Walthamstow a thorough air leakage test whenever it is needed. We have responsive scheduling options. Schedule for your air leakage testing at your comfort. We guarantee no delays or complications regarding scheduling.
AF Acoustics offers trustworthy and expert services. We know that clients want to receive their test results quickly. As a result, we endeavour to deliver test certificates by the next day.
AF Acoustics, a small business with low overheads, offers one of the best prices in Walthamstow and guarantees professional services.
Regardless of the size, type, or complexity of your domestic or commercial building in Walthamstow, 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. Air tightness test checks the extent of uncontrolled air moving through openings in the building envelope. The results are registered as The test results are described as m3/h/m2 – (m3 per hour) per square metre of building.
Approved Document L1A and L2A demands that buildings take tests for air leaks. 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. Too much air leakage leads to heat loss (and consequently, higher CO2 emissions) and discomfort. It can also create convective loops within a building; this is often referred to as thermal bypassing and wind washing. 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 get signed off by building control in Walthamstow, all buildings are to undergo air tightness testing and measure up to the required energy efficiency standards. For commercial constructions, air pressure tests result in a better environment for workers and customers. This increases the company’s productivity and lowers heating and cooling expenses.
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 leakage can occur through gaps, holes and cracks in the fabric of the building envelope (service penetrations, wall/roof junctions, etc), which are not always visible. 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 highest air permeability target set is 10m3/h/m2 but your building might need a much lower one. Air leakage affects the building’s energy performance and is required to meet Building Regulations Part L and measure up to the standard for low carbon buildings.
We can complete all your Part F and Part L testing requirements. We deliver quality air permeability and extract fan flow rate testing, and also recommend skilled experts who will handle your water calculations, SAP calculations and Energy Performance Certificates.
According to Part F, it is compulsory for a flow rate test to be conducted on all mechanical extract fans of new buildings. Evidence of this test must be passed to the Building Control Body (BCB) as part of their sign-off procedure. You can test, document and report the test of your building’s extractor fans in three ways. AF Acoustics employs the minimum benchmark procedure (method 3), which involves using a vane anemometer.
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. 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.
Air tightness testing determines the extent of air leaking out a building’s envelope. The result is expressed as a quantity in the form of m3 per hour, per square metre of building fabric. Air tightness testing is required for new builds. Your building may need a lower rate to meet the CO2 discharge target. The required air permeability rate for a dwelling can be found on the design-stage SAP report for that dwelling. An excessive amount of air leakage results in greater energy expenses, heat reduction and carbon dioxide emissions.
The measurement of air emitted by a building is tested to ascertain air permeability rating. The result is expressed as a quantity in the form of air pressure (m3 per hour) per square metre of building fabric. Document L2A of Building Regulations declares air leakage testing to be mandatory. The highest air permeability rate for your dwelling when tested should be 10m3/h/m2. 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. Uncontrolled air leakage can cause several problems. They are: infiltration of cold air, discomfort, reduction in heat, and higher CO2 emission rate.
We test the integrity of the smoke shaft to ensure the automatic opening ventilation is placed in the best condition. The automatic-opening vents are a key part of the fire strategy for multi-storey buildings to extract smoke in the case of a fire. For it to expel smoke from a building and keep the occupants safe during emergencies, the shaft must be air tight enough to create substantial pressure difference. AF Acoustics aims for the air permeability requirements of the automatic opening vent producers, so that their product can perform optimally. The shaft undergoes air leakage testing when fans are placed inside it. The usual openings are closed off too so that the shaft’s integrity can be determined. The fixing and commissioning of the auto opening vents happen after the test is completed.
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. It is important to ensure the ventilation strategy is working effectively. This helps to remove pollutants from the air and control excess humidity, particularly in rooms such as bathrooms and kitchens. Building Regulations Part F also requires that the air flow test of all extractor fans (such as kitchen and bathroom extract fans) in new buildings to be conducted and results given to Building Control before construction ends.
When a building is checked for the quantity of air flowing through the gaps in the fabric, it has undergone an air tightness test. Improving the air tightness of a building not only enhances the comfort of the occupants, but can also increases the building’s energy efficiency.
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. The most acceptable approach to show that a building fabric is impermeable is to identify leakage paths within it.
The new regulations stipulate that at least 20% of dwellings in a development be tested, but having a harmonious sample is dependent on the kind of buildings in the development. There is a penalty for untested constructions. Therefore, we suggest air leakage tests for all buildings.
Our test engineers require the drawings (plans and elevations) and target air permeability requirements of your building before taking the test. We would like to know the requirements and the building envelope’s size prior to testing. The tests take 30 – 60 minutes, and wind speed does not surpass 6m/s. To get the site ready, make the place air tight by closing and securing all external doors, windows, ventilation and smoke vents. Remember to turn off range cookers or stoves a day before testing as well as mechanical ventilation systems, and fill all drainage traps.
Before coming to the site, we get the measurement of the building’s envelope. The building envelope, is the physical barrier between the exterior and interior of a construction. The building envelope calculations are taken from the drawings and used for our air tightness testing.
Air permeability is calculated at air leakage rate per square metre of envelope area. In relation to air permeability, the air envelope area is the total area of the measured part of the building without subtracting from the area of the junction of internal walls, or floors and ceilings. The envelope area of a terraced house includes the party walls while that of a flat in a multi-storey building includes shared ceilings, walls and floors.
Air changes per hour are crucial to ventilation design, but it is only occasionally used as the base for the design or calculation. The calculation of residential ventilation rates is dependent on the area of the homes and number of occupants.
When evaluating the roof area of a building, it is important to ensure the area is the same as that of the ground floor. A cold roof is the kind of roof where the insulation is fixed in the ceiling joists with space between the insulation and roof rafters.
In a warm roof, an air barrier is inside the insulation which runs on the pitched roof rafters. In the warm part of the insulation, is the barrier between the conditioned and unconditioned space.
Evaluate the weather (barometric pressure, wind speed and temperature) Place the fan on an aperture within the building envelope. Ensure all the testing equipment is ready. Record the air volume flow through the fan (this equals the air leaking through the building envelope). Raise the fan speed from 20-25Pa to the highest speed of 55-60Pa. Record how the air pressure differs 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: The occupants will pay less for heat because less heat is lost and they won’t need equipment with high heating capacities. Your ventilation system will operate in a better way Reduced chance of mould and rot, as moisture is less likely to become trapped Thermal comfort is enhanced because air infiltration is lower. From a single dwelling to the largest commercial development, we offer stress-free compliance measurements to Part L Building Regulations and Building Standards. Our services include: air pressure testing, support services, re-examining designs and consultancy for all buildings in Walthamstow. We are cost effective and adhere to all building regulations.
Any new building has to be air tight. The 2010 Approved Document L1A of Building Regulations has made it compulsory. Less fuel and power are consumed by buildings. Part L1A states that new dwellings should be tested for air tightness in accordance with existing regulations.
During air leakage tests, there are technical standards that must be used. This was mandated by ATTMA – Air Tightness Testing and Measurement Association–to align with building regulations and other rules. 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.
If you’re constructing a new dwelling, you have to comply with Approved Document L1A’s stipulation to test it. Where there are two or more new buildings in an area, conduct a test on 50% of all examples of a kind of dwelling or 3 units of a dwelling kind. If the development has one or two dwellings only, an air tightness test might not be taken if the DET/TER calculations assume a value of 15m3/h/m2. To find if your building falls into this category, contact your SAP assessor. The method for testing required by the building regulations is stated in ATTMA TSL1 (for dwellings) and ATTMA TSL2 (for non-dwellings). Air leakage testing is compulsory for residential areas and certain Non-Dwellings. If your building has added an estimated assessed rate of 15 m3/h/m2 in its calculations or its useful floor space is less than 500 m2, it may not have to take the test.
ATTMA has a scheme for air leakage test organisations, which commenced in January 2015. The scheme was approved by the government and is stated in Technical Standard L1 and L2. Minimum Technical Competence (MTC) and National Occupation Standard (NOS) documents are the basis for the scheme.
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 report will be produced in accordance with company’s procedures, the relevant standards and the requirements of all relevant governing bodies.
We analyse our tests and results for any divergence from the standards required and check the air pressure rate against target rate. That way, our results are expressed in line with test standards. Clients’ test reports contain their names, construction, address; the tester’s name is also included. 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 we arrive on site, ensure you have sent us the air permeability target and been through the checklist below and the ones we have sent you. This will greatly facilitate the process.
Air Leakage Pathway List –Ensure you thoroughly check the following equipment. Fill up drainage traps. Here are the pieces of equipment to cover, fill or seal:
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.
