Air Tightness Testing, Certified by AF-Acoustics, in Margate

The measurement of air escaping from a building is called air tightness testing. It is also referred to as air permeability testing or air pressure testing. In 2006, Approved Document L was reviewed and building regulations for air permeability became more stringent. The test is presently a requirement for new buildings and reconstructions.

Air leakage occurs through any opening in the building envelope and can affect a building’s energy performance, this has been addressed by changes to the building regulations. AF Acoustics certificates are certified by Air Tightness Testing and Measurement Association (ATTMA). ATTMA is an association of specialists that concentrate on promoting the best air tightness measurements and air permeability testing techniques. Located in Margate, our company is a committed and accredited air permeability testing service provider; we provide air testing services. You can also contact us for assessments and consultancy services. In addition to air leakage testing, we provide Part F Mechanical extract fan flow rate testing.

As registered members of the ATTMA, our air tightness certificates are accepted as proof of building regulations sign-off. Not only do we test the air permeability of your building, we describe the procedure in a professional manner and advise you on problem areas discovered during the evaluation. Our goal is always value for money and customer satisfaction. We are professionals and our services are of the highest quality.

Our Guarantee

  • Over 15 years experience
  • State of the art equiptment
  • Onsite Support
  • Next Day Report Turn Around
Call us today for a quote on 020 3372 4430
Or you can email us at info@af-acoustics.com

Air Tightness Testing – What Does It Mean?

Air tightness testing is a technique whereby a newly constructed building is evaluated and the quantity of air leaking through is measured. It can also be called air pressure testing or air leakage testing. Air leakage is the draught or infiltration of unbridled air through the spaces and openings in a building. It is different from ventilation, which is the contained circulation of air within and outside the building. Draughts are uncontrolled ventilation. Using air tightness testing, the total air lost can be estimated. An excessive amount of uncontrolled air loss results in heat reduction, making the residents uncomfortable. Air leakage from buildings causes heat loss, more energy is then used to keep the building warm, this is a cause of excess CO2 emissions. This has resulted in regulations which are centred on decreasing air leaks from the building fabric, therefore lowering CO2 emissions. Air tightness testing is vital in determining the energy efficiency of a new building, air leakage and the build quality. With the introduction of tougher regulations, building designs will often consider air tightness at the early stages of the construction process, ensuring attention to detail during construction to create an air-tight envelope. 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

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. Once the atmosphere is windy, draughts infiltrate the building through holes in the fabric, leading to heat reduction and discomfort. 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 2006, air tightness of newly constructed buildings and non-dwellings with a floor area over 500m² became compulsory in England and Wales.

What Are the Problems Air Leakage Can Cause?

Air leakage causes heat loss. During windy weather, cold air infiltrates a building through the openings in its fabric. This results in heat loss. Movement of moist air into cavities in other parts of the building also occur. This process is called exfiltration. Once the moist air reaches the colder internal layer of the wall structure, the vapour in it condenses and forms droplets of liquid, which drawn into building materials and can potentially start a multitude of structural problems. Wet wooden framing or sheathing can rot and break down, diminishing its strength.

As the years go by, these conditions can result in structural damage.
Other damages that can occur are cold homes which make occupants uncomforta-ble, increase in heating bills to make the internal temperature warmer, and more carbon dioxide discharge since additional heat is required.

The best way to reduce the harmful effect of moisture is to efficiently control how air moves into and out of the building. An adequately installed air barrier reduces air leakage and condensation of water vapour on inner wall layers. To get rid of pollutants, water vapour and moisture odour, the building must be well ventilated.


Why is an Air Tightness Test Important?

Climate change caused by carbon dioxide emission is an environmental hazard that government is trying to curb. Energy performance and air tightness is a key part of this plan. Heating buildings contribute to global warming and CO2 emissions, since fossil fuels are used to create heat. The reduction of air leakage leads to lower heat loss and quantity of heat generated in a building. 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. Building tightly and ventilating the right way is highly recommended. Air leakage causes infiltration of moisture into the building envelope, leading to health issues and high repair costs.

When Do I Need an Air Tightness Test?

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 can affect a building’s energy ratings because they play a part in SBEM and SAP calculations. For big residential developments, the test is not required for each house. A group of diverse buildings are picked for the test. With selective testing, you get a penalty of +2m3/h/m2. Houses that have a target score of 5m3/h/m2 must get a lower score of 3.

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. 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.

Why Pick AF Acoustics for Your Air Tightness Testing?

At AF Acoustics, our air tightness testing expertise has helped many home and business owners in Margate. We are recommended by our clients for the following reasons.

Helpful service and expert knowledge

Our experience in serving diverse customers in Margate is proof of our ability to satisfy your requirements no matter the size and type of building, or your circumstance. We have competent and accredited air testing professionals who provide a quality, convenient service. If you need knowledgeable and trustworthy air leakage experts who can provide exemplary results, AF Acoustics is the team you need in Margate.

Registered by the Leading Air Tightness Body in UK

We are registered with ATTMA, a professional body that focuses on high quality air tightness testing and air permeability applications. This means our services are endorsed by the leading air leakage testing body in the UK.

When Can You Call Us to Test Your Building?

We want you to be able to access comprehensive air tightness testing in Margate whenever you need it. Pick a time that is convenient for you in our responsive scheduling options. We won’t make you wait or make the process complicated.

Next-day Turnaround on Test Certificate Where Possible

AF Acoustics offers a professional and reliable service; we understand that our clients are keen to get their test results as quickly as possible, to facilitate this process we strive to deliver next-day turnaround on test certificates.

Competitive Charges

At AF Acoustics, we offer the most competitive prices in Margate to ensure you have access to affordable air tightness testing when you need it. We keep the costs down, as we are a small business with low overheads. This allows us to be competitive with our pricing whilst guaranteeing a professional service.

Call us today for a quote on 020 3372 4430
Or you can email us at info@af-acoustics.com

Air Tightness Testing for Domestic & Commercial Buildings of All Types and Sizes in Margate

Regardless of the size, type, or complexity of your domestic or commercial building in Margate, 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. 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 result of the air leakage test 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 a building envelope.

Approved Document L1A and L2A requires that buildings know their air permeability rates by taking the air leakage test. 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. Several problems are caused by uncontrolled ventilation. They are:

  • Infiltration of cold air
  • Wind washing and thermal bypassing, which is when air moves through the inner building of a building fabric to create convective loops inside the walls, making the building less energy efficient
  • Reduction in heat and CO2 emission.

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. Air tightness testing is required by law for domestic buildings to ensure energy efficiency and comfort within the home environment. It is also a legal requirement that all new builds have an air tightness test carried out to meet energy efficiency standards before it can get signed off by building control in Margate. For commercial constructions, air pressure tests result in a better environment for workers and customers. The company also gets reduced heating and cooling costs and higher productivity rates.

Part L Test Explained

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 is also called air leakage rate or ‘air permeability’ rate. Air leaks through gaps and spaces in the building fabric such as service penetrations, walls and roof junctions. Sometimes, this is not obvious to occupants. Part L of the Building Regulations requires that all non-domestic buildings which have a gross floor area greater than 500m2, be subject to mandatory air permeability tests. For domestic dwellings, a sample of houses (in a development) must be tested. To comply with Part L the measured air permeability minimum requirement is 10m3/h/m2 but usually your air permeability target will be much lower. You can exceed the CO2 discharge and Building Regulations target and raise your building’s energy performance by testing for air leakage.

A Description of Part F Test

We will help you with all your Parts L and F requirements. In addition to conducting your air pressure test and extract fan flow rate testing, we can put you in contact with professionals who provide SAP calculations, Energy Performance Certificates, 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. Your building won’t be signed off until Building Control Body (BCB) has been presented the results of the test. Extractor fans can be tested and recorded, and test reports submitted using 3 methods. Use method 3 – the minimum benchmark method, which tests extractor fans with vane anemometers. This is our testing procedure.


The types of Air Tightness Testing Services We Offer

There are different levels of air tightness testing established from the size and complexity of a building. An overview of each is provided below: First Level – For building 1m3-4000m3, single and smaller non-dwellings, a single blower door fan is used to carry out the test. 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. Third Level – Testing is done for large high rise and phased handover buildings.

We Offer Air Leakage Testing of Apartments and Houses to Meet Approved Document L1 Standard

Air leakage testing is the measurement of uncontrolled ventilation from a building’s fabric. The result is written as m3 per hour per square metre of building. Part L1A of Building Regulations stipulates that such tests be conducted. A building has to achieve a lower rate to meet the carbon dioxide emission target. The design-stage SAP assessment SBEM of a construction records its required air permeability rate. Too much air leakage leads to heat loss which can lead to draughts and higher energy bills.

Commercial Building Testing as Required by Approved Document L2A

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. Part L2A of Building Regulations has demanded that such tests be conducted. The test results have a limit; they shouldn’t be higher than 10m3/h/m2. In order to comply with the SAP assessment, it may be necessary to achieve a lower air permeability rate. You can find the required air permeability rate of your building in its design-stage SAP or SBEM assessment. Excess air leakage causes heat loss, greater carbon dioxide discharge and influx of cold air.

Air Permeability Testing of Smoke Shafts (for automatic opening vents)

We provide smoke shaft tests to make sure it is air tight enough to let the automatic opening ventilation work optimally when it’s installed and commissioned. When there is a fire, the auto opening vents play an important part in expelling smoke in multi-storey buildings. For the vents and fans to operate at the expected level, the smoke shaft must be air tight to create a difference in air pressure and give emergency services when needed. To ensure that automatic opening ventilations work properly, their manufacturers have placed an air permeability target for them which we work towards. The shaft undergoes air leakage testing when fans are placed inside it. Once the fan is fixed, the extract points and ventilation grilles on each storey are sealed to ensure that the shaft is in proper condition. This test is conducted before the automatic opening ventilation is fixed and commissioned.

We Offer Extraction Fan Testing

The requirement for air tight buildings that are properly insulated has brought about the need for ventilation systems that are adequately installed and function at an optimal level. We are able to test extraction rates. This has not only been made compulsory by Building Regulations; it also helps reduce humidity in rooms, bathrooms and kitchens and expel pollutants. The air flow rates of all intermittent extractor fans, which are to be installed during the building process, are to be tested and the results submitted to the Building Control Body before work is completed.

Air Tightness Test and Building Preparation Method

The measurement of air pressure in a building is known as an air tightness test. If the rate of air pressure is good, the energy performance of a building will be high and the inhabitants will be comfortable.

Holes and spaces in a building’s fabric might be hidden by the internal building finishes, making them hard to find. The only satisfactory way to show that a building fabric is airtight is to detect and measure leakage paths within the building fabric.

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. Buildings that don’t undergo the test are penalised. All dwellings in a development should be tested to ensure optimum air tightness.

Pre-Test

Our test engineers would like to see the drawings (plans and elevations) and design 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. An air tight environment should be created in your building before the test to ensure optimal results. Do the following:

  • Seal and turn off all ventilation, smoke vents and mechanical ventilation systems
  • Close the windows and open internal doors
  • Fill drainage traps
  • Switch off range stoves/cookers 24 hours before the test

Building Envelope Measurement

We take the building envelope calculations before the test. The building envelope is the surface area of the structural barrier of a building. It separates the interior from the exterior part of the dwelling The building envelope calculations are taken from the drawings and used for our air tightness testing.

Air Permeability from the Envelope Area

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 Changes Per Hour

Air exchange rate is vital to ventilation design but it isn’t used as the determinant of the actual design or calculation. To calculate ventilation rates for domestic buildings, the area and number of people living in the building are considered.

Cold Roof Envelope Area Measurement

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 a roof that has the thermal insulation put in the ceiling with wide space between the insulation and pitched roof rafters.

Calculating the Envelope Area of a Warm Roof

In a warm roof, an air barrier is inside the insulation which runs on the pitched roof rafters. The envelope area is the barrier between the conditioned space in the insulation and the unconditioned space outside.

Building readiness

To get the building ready, close and secure all internal doors, windows, Temporarily seal vents and smoke vents. Also fill drainage traps.

Site Test Process

Evaluate the weather (barometric pressure, wind speed and temperature) Connect a fan to an opening, like the door, in the building fabric. Set up the testing gear. Using the fan, measure the air flow volume, from the building fabric. Gradually increase the speed of the fan to a maximum of 55-60Pa. Note the difference in air pressure in several parts of the building at each fan speed.

Air Leakage Measurement

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 Pressure Testing & 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: Your heating expenses are less because heat doesn’t escape through a permeable building, and you won’t require appliances with more heating capability. Better ventilation system Lower probability of mould because moist air won’t condense in the openings in the building envelope. Fewer draughts, causing more comfort 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:

  • Air tightness test
  • Consultancy
  • Design reappraisal
  • Support services

Good and Best Practice Standards

All new buildings, residential or commercial, must be air tight, according to Approved Document Part L1A of Building Regulations (2010). Reduced power usage and fuel conservation are important; that’s why the rule was put in place. Part L1A states that any new building must undergo an air pressure test, according to present regulations.

Testing for Air Permeability on Building Fabrics, According to L1 Technical Standard.

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. BS EN 13829:2001 and ISO 9972:2015 are clarified by the technical standards. The technical standards provide rules that ensure testing organisations get the same results from the same kind of tests and are based on BS EN 13829 “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”.

Call us today for a quote on 020 3372 4430
Or you can email us at info@af-acoustics.com

Part L 2010 Building Regulation Standards for England and Wales

Approved document L1A has made it compulsory for all new buildings to be tested for air leaks. For developments of two or more dwellings, an air leakage test should be carried out on the three units of each dwelling type; or 50% of all instances of that dwelling type. Where there are only one or two new buildings, add an assumed value of 15m3/h/m2 to the DET/TER measurements; an air tightness test may not need to be carried out. To find if your building falls into this category, contact your SAP assessor. ATTMA TSL1 and ATTMA TSL2 prescribe methods for testing occupied and unoccupied buildings. Both residential areas and many non-Dwellings are to take the air leakage test. Non-dwellings where floor area is less than 500 m2 or has an assumed assessed air permeability rate of 15 m3/h/m2 in their calculations, may not have to undergo the air leakage test.

Building Regulation Requirements Part L (England and Wales)

Most competent air pressure testing companies go through the ATTMA scheme, which began in January 2015, etence. The scheme is endorsed by the government and recognised by approved documents L1 and L2 of building regulations. It mirrors the operation standards and skill requirements set by the National Occupation Standard (NOS) and the Minimum Technical Competence (MTC) document.

There are three levels of testers:

  • Level 1: Testers can test dwellings and non-dwellings up to 4000m3 gross envelope volume when tested as a single entity, with a single fan.
  • Level Two: Testing for the air pressure is done in all single and multifaceted buildings. High rise (LCHR) buildings and phased handover/zonal buildings are excluded from this level, except a level 3 tester is in charge of the team.
  • Level 3: These are air tightness experts who can cover large, complex and or high-rise buildings and or phased handover or zonal compartmentalisation.

Report on Test for Air Permeability

Authorised companies, who test buildings of different types, sizes and complexities, give air tightness reports. Sealed extraction fans are sealed for testing and the details and results of the test are written in a report afterwards. The report will be produced in accordance with company’s procedures, the relevant standards and the requirements of all relevant governing bodies.

Outcome of Air Leak Test

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. We will ensure the report correctly identifies the tester, customer, building and its address. If a building fails the test, we provide remedial suggestions before a retest is carried out.

Resources Air Tightness Checklist – Dwelling

Send us your building design air permeability target and crosscheck the list below before we get to the site.

Air Permeability Pathway List – We will inspect every part for the building envelope for leaks.

  • Windows: Examine the seal below the sills and around the frames.
  • Doors: Inspect the seal around all external door surrounds. This is more applicable to French doors.
  • Drainage traps: Make sure they’re not filled with water.
  • Skirting and coving: Examine every part and seal where needed.
  • Meter Boxes: Make sure the external supplies are properly covered.
  • Light Fittings: Inspect the seal around all light fittings and switches.
  • Radiators/Fans /Heaters: Check the seal on pipes and wires.
  • Boilers: Inspect the seal around the boiler supply and flue.
  • Extractor Fans: Inspect the edge of the extracts and seal the front of the grill.
  • Cooker Hoods: Examine the seals around all penetrations.
  • Soil pipes: Inspect the seal around all soil pipes and sink waste pipes especially those inside or behind kitchen cupboards.
  • Bath Panels: Make sure all the pipes behind bath panels are sealed properly.
  • Hot water tank: Examine the seal around supply pipes.
  • MVHR: Examine seal around all terminals.
  • Chimneys: Cover the open fireplaces.
  • Junction between floor and wall under kitchens and baths
  • Tumble drier extracts: Study the seal around the extract.

Here are the appliances you should seal temporarily;

  • Cooker hoods
  • Extractor fans/MVHR terminals
  • Trickle vents
  • Chimney flues and air bricks

Air Tightness Testing FAQ’s

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:

  • Smoke pens– smoke can be used to identify where air is moving when the building is being tested
  • Depressurise the building –By depressurising the building air is drawn in and can be felt at the air leakage points, our experience will be able to pin point these locations easily, whist the building is being depressurised, we will be able to show you around and will point you to the areas that have air leakage. You will usually be able to feel the air blowing on your skin when you are close to leakage areas, using the smoke pens these leakage points can be seen as the smoke changes from a steady flow to a turbulent flow.
  • Smoke testing – if the air paths are less direct it may be necessary to use smoke puffers and/or fill the building with smoke and pressurise/depressurise again. Points of air ingress and egress should be identifiable.
  • Thermography – if it is still not apparent where air is escaping, infra-red cameras can be used to identify hot spots and cold spots on the internal and external surfaces of the building. This requires a temperature difference between the inside and outside.

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:

  • Have at least 7 points (ideally 10 or more).
  • At least one building pressure >50Pa and at least on <50Pa, No building pressures >100Pa.
  • The lowest figure should be at least 10 Pa or 5 times the ‘static pressure’ (the pressure difference between inside and outside without the fans)
  • The readings should be no more than 10 Pa apart.
  • The correlation coefficient r2 >0.98
  • The gradient of the graph (n) should be between 0.5 and 1.0.

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:

  • The building should be ‘completed’
  • All external doors and windows closed
  • All internal doors wedged open
  • All fire dampers, ventilation louvres and trickle vents closed but not sealed
  • Mechanical ventilation turned off with inlet/outlet grilles sealed
  • All combustion appliances switched off
  • Drainage traps must contain water
  • Any ‘Aga’ type stoves must be switched off for a minimum of 24 hours prior to testing

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.

  1. How many plots are going to be tested
  2. The location
  3. The plans and elevation drawings, cross sections if possible
  4. The air permeability target
  5. A brief description of the property; e.g. does it have fireplace or a loft?

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

  • Holes in the walls
  • Radiator pipe work penetrations in floors and walls
  • Sanitary pipes penetrating walls and floors
  • Junction between floor and wall under kitchens and baths
  • Junction lower floor / vertical wall
  • Junction window sill / vertical wall
  • Junction window lintel / vertical wall
  • Junction window reveal / vertical wall (horizontal view)
  • Vertical wall (cross section)
  • Perforation vertical wall
  • Junction top floor / vertical wall
  • Penetration of top floor
  • Junction French window / vertical wall
  • Junction inclined roof / vertical wall
  • Penetration inclined roof
  • Junction inclined roof / roof ridge
  • Junction inclined roof / window
  • Junction rolling blind / vertical wall
  • Junction intermediate floor / vertical wall
  • Junction exterior door lintel / vertical wall
  • Junction exterior door sill / sill
  • Penetration lower floor / crawlspace or basement
  • Junction service shaft / access door
  • Junction internal wall / intermediate floor

Our team of experts can support you through the following

  • Tender Stage – Estimate pricing structures and general advice
  • Design Stage – Desktop or site-based design team meetings
  • During Construction – Ongoing audits of the building, Building Control liaison, sample testing of completed areas of ‘comfort testing’ prior to final testing
  • Upon completion – preparation advice, shortly prior to the air testing, final testing and leakage diagnosis

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:

  • The insulation values of building elements
  • The allowable area of windows, doors and other openings
  • Air permeability of the building
  • The heating efficiency of boilers
  • The insulation and controls for heating appliances and systems together with hot water storage and lighting efficiency

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:

  • Solar heating and heat gains to buildings
  • Heating, mechanical ventilation and air conditioning systems
  • Lighting efficiency
  • Space heating controls
  • Air permeability
  • Solar emission
  • The certification, testing and commissioning of heating and ventilation systems
  • Requirements for energy metres

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:

  • Check site preparation / Prepare site – including temporary sealing.
  • Calculate the envelope area.
  • Take environmental condition measurements – wind speed, temperatures, barometric pressures.
  • Install door frame canvas for the fan into a suitable aperture(s), usually the front door.
  • Install fan(s) into frame canvas
  • Connect monitoring equipment.
  • Check the static pressure.
  • Take multiple pressure difference readings and record fan flow rate(s) – allowing sufficient time for the pressure readings to stabilise.
  • Check the static pressure.
  • Process the readings through appropriate software – check that readings fulfil the requirements of the standard.
  • If the building fails, attempt to identify/quantify air leakage/infiltration paths.
  • Disconnect measurement equipment.
  • Remove the fan(s).
  • Remove the door frame canvas.

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:

  • ‘Small’ commercial buildings (with a floor area less than 500m2) may avoid the need to test by accepting an assumed poor value for air permeability (15m³/(h.m²) at 50 Pa) but this may add costs to other aspects of the building specification so that the building meets the overall target for emissions.

No. Air tightness testing applies to:

  • All new dwellings (based on a sampling rate)
  • All new buildings other than dwellings
  • Extensions to existing buildings that create new dwellings

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:

  • heat loss
  • discomfort (cold homes)
  • increased heating bills (to counter the cold)
  • greater CO² emissions (as result of additional heating required)

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Gerard Finn

AF Acoustics lead air tightness testing Specialist, Gerard is your first port of call for all air tightness questions enquiries and surveys.