Air tightness testing, also called air leakage testing or air pressure testing, calculates the quantity of air escaping through openings in a building. Since Approved Document L was reviewed in 2006, air tightness testing has become an essential part of building regulations for newly completed and rehabilitated buildings.
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 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 a dedicated and approved air leakage testing service in Hayes and we can provide air permeability measurement whenever you require. We also provide Part F mechanical extract fan flow rate testing, assessments and consultancy services.
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. 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. We deliver professional value for money service to the highest standards.
Air tightness testing is a technique whereby a newly constructed building is evaluated and the quantity of air leaking through is measured. 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. Unrestrained air movement leads to heat reduction, making the inhabitants of the building 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 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. Incorporating this at the beginning of the construction process makes the development more cost effective and energy efficient.
Air leakage is uncontrolled air movement in a building due to cracks. Air leakage is the uncontrolled movement of air into and out of a building through gaps and spaces in the building’s fabric. Also known as infiltration, it is different from ventilation, which is air that enters a building in a controlled manner. Once the atmosphere is windy, draughts infiltrate the building through holes in the fabric, leading to heat reduction and discomfort. How do you know if a building is energy efficient? By testing its air permeability. This lets the occupants know if the building meets standard air-tightness requirements. Air tightness testing is compulsory for all new constructions and non dwellings with a floor area over 500m² in England and Wales. This came into effect in 2006.
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. Once there’s infiltration, exfiltration will occur in another part of the building. Warm, moist air seeps into cool cavities in the building’s fabric. 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. The strength of the outer wooden covering is drastically reduced because it is wet.
The building becomes structurally damaged as time goes on.
Other impacts include:
These effects can be mitigated by controlling the circulation of air into and out of the building. Adequately installed air barriers minimise air leaks and the probability of vapour condensing and diffusing into the building’s structure. Passive or active ventilation is required to reduce water vapour, moisture odour and pollutants.
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. Fossil fuel is burnt to heat up a building. This leads to a discharge of carbon dioxide which increases 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. Building tightly and ventilating the right way is highly recommended. The result of uncontrollable air moving into the building fabric could be health problems and costly repairs.
It is best practice to complete an air tightness test early on and then again at the final stage. The test results are used in SAP and SBEM calculations, this impacts the energy rating of new building. Individual property is not tested in a large residential development. The test is done on different types of houses within the area. This type of testing attracts a penalty of +2m3/h/m2, consequently, if the target result is 5m3/h/m2, a lower score of 3 would have to be attained.
If the building has not been tested for air tightness, assessed air permeability rate is the average result of similar buildings in the area +2m3/h/m2 at 50 Pa. Selective testing is not recommended because: i.It is quite tough to achieve the lower air permeability rate set for untested dwellings. ii.The proper air tightness rate for each building in the development cannot be attained, as only some underwent air tightness testing; a tested building might be much tighter than an untested one.
With AF Acoustics, homes and businesses in Hayes have been getting quality air tightness testing. Our clients highly recommend us for the following reasons.
Due to years of experience in conducting air tightness testing in different kinds of buildings in Hayes, we have the skills to meet your needs no matter the type or size of your property. We have competent and accredited air testing professionals who provide a quality, convenient service. Our personnel will use their expertise to provide lasting solutions. Contact AF Acoustics in Hayes –the right team for your building.
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 Hayes whenever you need it. Simply fix a convenient time for your building’s air permeability test. We offer responsive scheduling. We guarantee no delays or complications regarding scheduling.
Our customers are eager to get their test results. AF Acoustics, which provides reliable, competent services, strives to issue test certificates on the next day.
AF Acoustics, a small business with low overheads, offers one of the best prices in Hayes and guarantees professional services.
We can test any building in Hayes for air leakages irrespective of its size, complex nature or type. Our tests are conducted by highly qualified professionals and we issue ATTMA certificates. An air leakage test is used to determine the level of uncontrolled air flow through gaps or cracks in the fabric of a building. The results are written as The test results are described as m3/h/m2 – (m3 per hour) per square metre. of a building envelope.
Approved Document L1A and L2A demands that buildings take tests for air leaks. Each building tested must achieve a maximum air permeability rate of 10m3/h/m2. In order to comply with the carbon emission target, it may be necessary to achieve a lower air permeability rate. The required air permeability rate for each building can be found on the design-stage SAP assessment or SBEM for that building. 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 get signed off by building control in Hayes, all buildings are to undergo air tightness testing and measure up to the required energy efficiency standards. With air leakage tests, business areas are more comfortable for employees and customers. The company also gets reduced heating and cooling costs and higher productivity rates.
Air tightness testing has been a mandatory part of the Building Regulations for new build and refurbishment projects since Approved Document L was revised in 2006. Air tightness can also be called air leakage or air permeability rate. Any hole or crack in a building fabric is a spot where air leak can take place. Air leakage points are not often visible. Part L of the Building Regulations requires that all non-domestic buildings which have a gross floor area greater than 500m2, be subject to mandatory air permeability tests. For domestic dwellings, a sample of houses (in a development) must be tested. The highest air permeability target set is 10m3/h/m2 but your building might need a much lower one. Air permeability is key in the following areas: i. A construction’s energy performance, ii. CO2 emission targets iii. Building Regulations Part L standards
We will help you with all your Parts L and F requirements. First, we provide extract fan flow rate and air leakage testing. Then we put you in contact with competent professional to work on your Energy Performance Certificates, SAP and water calculations.
According to Part F, it is compulsory for a flow rate test to be conducted on all mechanical extract fans of new buildings. Building Control Body (BCB) will see proof that the test has been conducted before signing off your building. Extractor fans can be tested and recorded, and test reports submitted using 3 methods. We use a vane anemometer, which is the third method called the minimum benchmark method, to conduct extract fan flow rate tests.
Here are the descriptions of the ways air permeability can be tested: Level 1: Air pressure testing for single dwellings and other smaller non-dwellings up to 4000 m³ gross envelope volume, typically tested with a single blower door fan. Air tightness testing for dwellings more than 4000m3, except big phased handover/zonal and high rise (LCHR) constructions is done. Level Three: At this level, tests for the air pressure of high rise (LCHR) buildings and phased handover/zonal buildings.
Air tightness testing determines the extent of air leaking out a building’s envelope. The result is written as m3 per hour per square metre of building. Air tightness testing is required for new builds. Your building may need a lower rate to meet the CO2 discharge target. The required rate can be found in a building’s design-stage SAP assessment SBEM. Excess air leakage causes heat loss and discomfort due to the influx of cold air, also causing increased energy bill expense.
Air pressure testing involves the calculation of air escaping through the openings in a building. The test results are inscribed using m3 per hour per square metre. Air pressure testing is compulsory, according to Approved Document L2A. Each building tested must achieve a maximum air permeability rate of 10m3/h/m2. In order to comply with the SAP assessment, it may be necessary to achieve a lower air permeability rate. The air permeability target can be found in a building’s design-stage SAP or SBEM assessment. Air leakage causes heat loss, increased energy bills, greater CO2 emissions, and an uncomfortable atmosphere for inhabitants due to draughts.
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 are crucial during fire emergencies in storey buildings, as they clear out smoke from the buildings. The performance of the fans and vents depends on the air tightness of the shaft. Air tight shafts have enough pressure difference to extract smoke and save people inside a building during fire emergencies. With the right air permeability rate, the vents can operate at their best. We aim for the air permeability rate set by the vent manufacturers. An air pressure test is taken for the smoke shaft by installing a fan inside. The usual openings are closed off too so that the shaft’s integrity can be determined. Smoke shaft tests occur before installing and commissioning automatic opening ventilation.
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 are able to test extraction rates. A building must have an optimal ventilation system to dispel humidity from bathrooms, kitchens and other rooms and extract odours and pollutants. We can also help you meet the Building Regulations targets. Part F states that all new constructions must have intermittent extractor fans whose air flow rates will be calculated and the results given to Building Control before the building work is finished.
The measurement of air pressure in a building is known as an air tightness test. The greater the air tightness of a building, the more comfortable the occupants are and the higher its energy performance.
Holes and spaces in a building’s fabric might be hidden by the internal building finishes, making them hard to find. If you know the leakage paths of a building, you will know if it is air tight.
Under the new regulations developers must test 20% of the dwellings on a site but this also depends on the amount of differing house types to ensure that a consistent sample is taken throughout the construction of the development. There is a penalty for untested constructions. Therefore, we suggest air leakage tests for all buildings.
Send the drawings of your dwelling (plans and elevations) and its target air permeability requirements to our test engineers. 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.
We take the building envelope calculations before the test. The building envelope is the surface area of the thermal boundary of the building. We use the building envelope measurements to get the right results when testing for air tightness.
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.”
The air change rate is important in designing a ventilation system, however, it is hardly a part of the actual design. 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 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.
Check weather conditions (wind speed, temperature, barometric pressure); Place the fan on an aperture within the building envelope. Fix the instrument for testing. Using the fan, measure the air flow volume, from the building fabric. Increase the speed of the fan slowly till it gets to 55-60Pa. Record how the air pressure differs at each fan speed.
Our competent engineers note the points of air leakage, examine the test data and send test results to the customer in a technical report. If the test fails, we inform clients on what to do about it. Air Leakage Testing and 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 The ventilation system will operate optimally Lower probability of mould because moist air won’t condense in the openings in the building envelope. Fewer draughts and enhanced comfort 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 Hayes. We are cost effective and adhere to all building regulations.
The Building Regulations approved document Part L1A 2010 specifies that any new dwellings must be airtight. 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.
ATTMA has specified technical standards that must be adhered to while testing buildings in the UK, according to building regulations and other documents. This Technical Standard provides detailed guidance and clarification of BS EN 13829:2001: “Thermal Performance of Buildings. Determination of air permeability of buildings. Fan pressurisation method” and ISO 9972:2015: “Thermal performance of buildings – Determination of permeability of buildings – Fan pressurization method”, in order to ensure consistency by testing companies.
If you’re constructing a new dwelling, you have to comply with Approved Document L1A’s stipulation to test it. 50% or 3 units of each dwelling type should undergo an air leakage test in the case of an area with two or more dwellings. 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 let you know if you can do this for your building. A testing procedure required by Building Regulations is expressed in ATTMA TSL1 for dwellings and ATTMA TSL2 for non-dwellings. Air leakage testing is compulsory for residential areas and certain Non-Dwellings. 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. It mirrors the operation standards and skill requirements set by the National Occupation Standard (NOS) and the Minimum Technical Competence (MTC) document.
Accredited testing companies issue air pressure reports. Temporary sealing of extraction units will be done by the tester; all test results will be noted, and a shortened form report will be written which will include the findings of the test. The organisation makes sure the report meets the company and government’s requirements.
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. 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 List – We will inspect every part for the building envelope for leaks.
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.
