Air tightness testing, otherwise called air pressure testing or air leakage testing, is the measurement of the outflow of air from a building’s fabric. 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.
Because air leakage is the process whereby air escapes through any crack or hole in the building envelope and influences its energy performance, building regulations have been modified to ensure a building has adequate air tightness. 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. AF Acoustics, a licensed air tightness testing company, is available to provide testing services at your request. Our address is Whitstable. 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 are professionals who take the time to explain the testing process, we are able to give informed advice on where problem areas may occur during testing, and how improvements can be made based on results of air pressure testing. Our goal is always value for money and customer satisfaction. We are professionals and our services are of the highest quality.
Air tightness testing is a method of measuring the extent to which air is lost through leaks in the building fabric. Air leakage and air pressure are also used in place of air tightness. Air leakage should not be confused with ventilation. Also called draughts or infiltration, air leakage is unrestrained movement of air through holes in a building fabric, while ventilation is the restrained and planned movement of air. Air leakage is uncontrolled ventilation. Air tightness testing is the approved method for gauging the entire air that has leaked through a building fabric. Unrestrained air movement leads to heat reduction, making the inhabitants of the building uncomfortable. The government aims to lessen the quantity of air flowing from newly built buildings. Therefore, regulations have been put in place to reduce uncontrolled ventilation from the building envelope, sustaining the right temperature conditions without using so much fuel. Air tightness testing is important in establishing air leakage from a building’s fabric, the energy efficiency of a new building and in identifying poor build quality within new developments. 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. This can make a building more energy efficient since air leakage is under control. It will also be cost effective and of high quality.
Air leakage occurs when air escapes through holes and gaps in a building. It is not the same as ventilation which is regulated air flowing into a building. It is also called infiltration. It leads to heat deprivation when cold draughts happen and warmth is needed the most. Because air leakage is uncontrolled ventilation, excessive air flows into the house during windy and wintry weather. 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 obligatory since 2006. All new dwellings and non-dwellings over 500m² are to be tested for air permeability.
Air leakage leads to heat reduction. 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 water vapour in the moist air condenses on the inner wall surface holes. After a while, it is absorbed into building materials and diffuses, causing potential structural problems. Wet wooden framing or sheathing can rot and break down, diminishing its strength.
Over the years, these problems can damage the building’s structure.
The inhabitants become uncomfortable because of chilly homes, heating expenses increase and more CO2 is emitted due to the additional heat required.
The best way to reduce the harmful effect of moisture is to efficiently control how air moves into and out of the building. The potential of vulnerable wall structures to absorb condensed moisture is reduced when air barriers are properly installed and uncontrolled air flow is reduced. 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. Home heating involves burning up fossil fuel which produces carbon dioxide and aids global warming. Reducing air leakage reduces heat loss, which in turn reduces the amount of energy a heating system uses. Uncontrolled air leakage also results in health problems. Coupled with poor air circulation, it leads to the growth of mould and mildew. Best practice advice is to “Build tight, ventilate right”. Air leakage causes infiltration of moisture into the building envelope, leading to health issues and high repair costs.
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 results of the test can affect a building’s energy ratings because they play a part in SBEM and SAP calculations. 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. Selective testing is not advisable, as it does not give a realistic picture of the air tightness of each individual building. A tested property might be a lot tighter than an untested property. Also, the penalty implemented on the untested houses make air permeability rates very difficult to achieve.
Numerous businesses and home owners have been aided by AF Acoustics air tightness testing proficient skills in Whitstable. Our clients highly recommend us for the following reasons.
In Whitstable, we have served many clients. The experience garnered from our years of service will help us meet your specific needs no matter the size or type 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. Do you need trustworthy professionals who will provide great results in Whitstable? Contact AF Acoustics today.
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.
You can access our complete air tightness test in Whitstable at anytime. We have responsive scheduling options. Schedule for your air leakage testing at your comfort. You won’t get delays or difficulties when 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 Whitstable and guarantees professional services.
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. Air permeability testing calculates how much air moves through spaces in your building’s fabric. The result is expressed as a quantity in the form of The test results are described as m3/h/m2 – (m3 per hour) per square metre. of building fabric.
Air tightness testing is recommended by Approved Document L1A and L2A. A maximum air permeability rate of 10m3/h/m2 is required. However, a building has to achieve a lower rate to meet the carbon emission target. To get your building’s required air permeability rate, check its design-stage SAP assessment SBEM. Excess air leakage causes heat loss, greater carbon dioxide discharge and can make occupants uncomfortable due to the influx of cold air. It also causes wind washing and thermal bypassing, resulting in lower energy performance. Exfiltration/infiltration of air is caused by the difference in air pressure inside and outside the building. Lower pressure occurs as warm air rises and brings air inside through any available opening. In Whitstable, the law demands that all new buildings be tested for air pressure before they can be approved and signed off by building control. This enables dwellings achieve energy efficiency standards. Clients and employees will be at ease in their surroundings. It will also help you reduce the cost of maintaining heating or cooling in your commercial building, making it 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. Air tightness can also be called air leakage or air permeability rate. Air leakage can happen via holes and splits in the texture of the building envelope (divider/rooftop sections, service penetrations, etc), which may not be obvious. Part L of the Building Regulations requires that all commercial buildings greater than 500m2 undergo air tightness testing and a selection of residential buildings in a development be tested. The maximum air permeability rating allowed is 10m3/h/m2, but your building might need a lower rating ts. You can exceed the CO2 discharge and Building Regulations target and raise your building’s energy performance by testing for air leakage.
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.
Approved Document F of the Building Regulations demands that all mechanical extract fans in newly completed constructions undergo a flow rate test. 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. Using a vane anemometer, our testing procedure follows Method 3 – The minimum benchmark method.
Here are the descriptions of the ways air permeability can be tested: Level 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. 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. The third level tests big and complex zonal and phased buildings and complex high rise buildings.
Air tightness testing determines the extent of air leaking out a building’s envelope. 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 pressure testing is compulsory, according to Approved Document L1A. A lower air permeability rate might be needed due to carbon emission requirements. The design-stage SAP assessment SBEM of a construction records its required air permeability rate. Air leakage leads to heat loss, increased energy bills, greater CO2 emissions, and an uncomfortable atmosphere for inhabitants due to draughts.
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. Air leakage testing is a requirement of Approved Document L2A. 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. Too much air leakage leads to heat loss (and consequently, higher CO2 emissions) and draught.
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. The performance of the fans and vents depends on the air tightness of the shaft. Air tight shafts have enough pressure difference to extract smoke and save people inside a building during fire emergencies. To ensure that automatic opening ventilations work properly, their manufacturers have placed an air permeability target for them which we work towards. Fans are placed in the smoke shaft to conduct an air tightness test. The usual openings are closed off too so that the shaft’s integrity can be determined. The test takes place in advance of the automatic-opening ventilation equipment being installed and commissioned.
The mandate to construct well insulated and air tight buildings, has made it crucial for satisfactory, enhanced and balanced ventilation systems to be installed. 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.
Air tightness test determines the level of air permeability in a building. The air tightness of a building improves its energy efficiency and internal environment.
Gaps and cracks in the building that cause air leakage are often difficult to detect. They may be obscured by the internal building finishes. The best solution to demonstrate a building’s air tightness level is to check for leakage paths in the building envelope.
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.
Clients should send the drawings (plans and elevations) and air permeability requirements to our engineers. 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. To prepare the site for the test, do the following:
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 calculations, which are extracted from the drawings, are fed into our estimations when testing your building for air leaks.
Approved Document L1A Conservation of Fuel and Power in New Dwellings (2010) defines air permeability as “air leakage rate per hour per square metre of envelope area at the test reference pressure differential of 50 pascals (50n/m2)” and envelope area as “the total area of all floors, walls and ceilings bordering the internal volume that is the subject of the pressure test. This includes walls and floors below external ground level. Overall internal dimensions are used to calculate this envelope area and no subtractions are made for the area of the junctions of internal walls, floors and ceilings with exterior walls, floors and ceilings.”
Air change rates are often used as rules of thumb in ventilation design but they are seldom used as the actual basis of design or a calculation. The calculation of residential ventilation rates is dependent on the area of the homes and number of occupants.
It is important to make sure the roof area and ground floor area of a building are equal. A cold roof is a roof that has the thermal insulation put in the ceiling with wide space between the insulation and pitched roof rafters.
A warm roof is a roof where the insulation is installed on top of the roof structure. The envelope area is the barrier between the conditioned space in the insulation and the unconditioned space outside.
Check all weather conditions such as temperature, wind speed and barometric pressure. Connect a fan to an aperture within the construction envelope. For example, the door. Set up testing equipment. Using the fan, measure the air flow volume, from the building fabric. Gradually increase the fan speed from 20-25 Pa to a maximum of 55-60Pa. The pressure differences in the building at each fan speed should be calculated.
We can determine where air leakage is occurring through our test procedure. Once the test has been completed, we crosscheck the data and send a report to you. If the test fails, we will advise you about corrective measures. Air Pressure Testing & Compliance
When a building has the right kind of ventilation (mechanical, natural or a combination of both) and has a low permeability rate, the advantages to the occupants are numerous. Some of them are: Lower heating bills due to less heat loss, with potentially smaller requirements for heating and cooling equipment capacities Better ventilation system Lower probability of mould because moist air won’t condense in the openings in the building envelope. Infiltration of air is reduced and the inhabitants are more comfortable. Our clients can expect a stress-free conformity to Part L Building Regulations standards, whether they have a single building or a large commercial building. They also ensure that you spend less money. Here are the services we provide:
The Building Regulations approved document Part L1A 2010 specifies that any new dwellings must be airtight. The regulation helps to reduce the use of fuel and power. The dwelling should be tested for air permeability in line with existing building standards, as stipulated by Approved Document Part L1A.
ATTMA has specified technical standards that must be adhered to while testing buildings in the UK, according to building regulations and other documents. The technical standards ensure that all companies have similar testing procedures. They are:
Test for air permeability must be conducted on your new constructions. This is stated in Approved Document L1A. 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. A development with only two dwellings may not undergo a test if a suggested value of 15m3/h/m2 is stipulated in the DER/TER measurements. Your SAP assessor will be able to confirm if this is the case for your dwelling. A testing procedure required by Building Regulations is expressed in ATTMA TSL1 for dwellings and ATTMA TSL2 for non-dwellings. Both residential areas and many non-Dwellings are to take the air leakage test. Buildings with a floor area of less than 500 m2 might not have to take the test. Where air tightness testing is not done, an assumed air permeability rate of 15 m3/h/m2 is used.
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. Its basis is the National Occupation Standard (NOS) and Minimum Technical Competence (MTC) documents standard for testing and essentials for testing knowledge.
Accredited testing companies issue air pressure reports. The testing companies seal extraction fans. After the test has been completed, they record test findings and results 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.
AF Acoustics guarantees the test outcome is written in line with standard requirements; it picks out any deviations from the significant benchmarks inside the report and checks air permeability against target values. The identity of the customer, tester, building and address are correctly written in our report. In the event that a building fails the test, we suggest methods of improving the building and what repairs to do on the building fabric if a retest is required.
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 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.
