ATTMA Licensed Air Tightness Testing in Kidlington

Air tightness testing, also known as air leakage testing or air permeability testing, establishes the rate at which air flows out of gaps in a building fabric. Air tightness testing has been a compulsory part of the building regulations for new dwellings, renovations and commercial projects since the revision of Document L in 2006.

Changes to building regulations have addressed air leaks which affect a building’s energy efficiency. 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 Kidlington, our company is a committed and accredited air permeability testing service provider; we provide air testing services. We also provide Part F mechanical extract fan flow rate testing, assessments and consultancy services.

We are registered members of the ATTMA. As a result, our air tightness certificates prove that the building requirements for your building have been met. We don’t just provide air tightness testing. We describe the process thoroughly, give expert advice on areas that could be problematic during testing, and suggest improvements based on the air permeability rating of the building. We deliver professional value for money service to the highest standards.

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

What is the Assessment of a Building’s Air Tightness?

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 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 tightness testing evaluates the complete air leakage a building has in every gap available. The air leakage is known as uncontrolled ventilation. 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. With air tightness testing, you can determine whether or not air is leaking from a building’s envelope, the build quality and energy efficiency of new developments. The building regulations have made air tightness part of the building’s design from the beginning of the construction. This ensures that the fabric of a building is air tight. When the building fabric is properly constructed to reduce air loss, the building is economical, and energy efficient.

Air Leakage

Air leakage occurs when air escapes through holes and gaps in a 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 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.

What Are the Problems Air Leakage Can Cause?

Air leakage leads to heat reduction. Once the atmosphere is cold and windy, unwanted chilly air infiltrates the building through gaps, leading to heat reduction. Movement of moist air into cavities in other parts of the building also occur. This process is called exfiltration. The warm air is filled with moisture, which hits the inner wall surface and condenses. Moisture is sucked into the building material, and this can lead to serious structural issues. The strength of the outer wooden covering is drastically reduced because it is wet.

These problems will eventually cause structural harm to the building.
Air leakage can also cause these problems:

  • Colder homes that result in discomfort
  • Higher heating expenses
  • Reduction in CO2 emissions’

The key to minimising the damage potential of moisture is effectively managing the flow of air into and out of the building. An adequately installed air barrier reduces air leakage and condensation of water vapour on inner wall layers. Correct ventilation, whether passive or active, ensures fresh air circulates through the building, eliminating water vapour, moist odour and polluting substances.


Why is an Air Tightness Test Important?

The energy performance of a building is determined by how air tight it is. Energy performance affects CO2 released from buildings. As a result, air tightness testing is a method government has devised to regulate climate change. Environmental change caused by carbon dioxide emissions and global warming is partly aided by the burning of fossil fuels to generate heat. Reducing air leakage reduces heat loss, which in turn reduces the amount of energy a heating system uses. There are also health issues associated with uncontrolled air leakage. When a building has poor levels of controlled ventilation and high levels of uncontrolled air leakage, this can cause excessive moisture and mould growth, leading to poor health. 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.

When Do I Need an Air Tightness Test?

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 are used in SAP and SBEM calculations, and can influence a building’s overall energy rating. Large residential areas do not need each building to be tested. Instead, different types of dwellings are tested. 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.

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 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.

The reasons Why You Should Choose AF Acoustics for Your Air Tightness Testing

AF Acoustics air tightness testing professionalism has helped many homes and business owners in Kidlington. We come highly recommended by our clients because of the following guarantees.

Great service and expertise

Having served many clients in Kidlington, we have the expertise to work on any type or size of building. We’ll work with you to carry out our tests and consultations at times that are convenient to you, delivering an exceptional quality, convenient service. Do you need trustworthy professionals who will provide great results in Kidlington? Contact AF Acoustics today.

We Are Registered Members of the Air Tightness Testing and Measurement Association (ATTMA)

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?

Our comprehensive air permeability testing in Kidlington is available. We have responsive scheduling options. Schedule for your air leakage testing at your comfort. You won’t get delays or difficulties when scheduling.

You Could Get Your Certificates on the Next Day

AF Acoustics has professional speedy services to satisfy clients who want their test results immediately. We have a next day turnaround policy for our test certificates and endeavour to deliver in all situations.

Fair Pricing

AF Acoustics offers competitive fees in Kidlington. Since we’re a small business, we offer less expensive air permeability testing and render high quality services.

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

We Conduct Tests for All Types of Buildings in Kidlington

We can test any building in Kidlington for air leakages irrespective of its size, complex nature or type. Our tests are conducted by highly qualified professionals and we issue ATTMA certificates. The best way to determine how much air seeps through a building’s fabric is through air permeability testing. The test results are described as The test results are described as m3/h/m2 – (m3 per hour) per square metre..

Approved Document L1A and L2A requires that buildings know their air permeability rates by taking the air leakage test. The design-stage SAP assessment or SBEM of a construction records its required air permeability rate. While the law requires the highest air permeability rate to be 10m3/h/m2, your building might have to get a lower rate to meet the carbon emissions target. With air leakage comes heat loss, greater CO2 discharge, draughts, thermal bypassing and wind washing and poor 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. 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 Kidlington. 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

Since Approved Document L was reviewed in 2006, building regulations have demanded that new and rehabilitated constructions conduct air tightness test. The air-tightness of a building is known as its ‘air permeability’ or leakage 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. It is compulsory for all commercial buildings with a gross area greater than 500m2 and a representative selection of domestic buildings to undergo air pressure test, as stipulated by Part L of the Building Regulations. To comply with Part L the measured air permeability minimum requirement is 10m3/h/m2 but usually your air permeability target will be much lower. Air tightness is important for meeting the Building Regulations Part L standards, exceeding requirements for low carbon buildings, and overall energy efficiency.

The Part F Test

We will help you with all your Parts L and F requirements. 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. Building Control Body (BCB) will see proof that the test has been conducted before signing off your building. You can test, document and report the test of your building’s extractor fans in three ways. Using a vane anemometer, our testing procedure follows Method 3 – The minimum benchmark method.


What Kinds of Air Tightness Testing Services Do 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: A single blower door fan is the instrument used for the first level to examine single buildings and smaller non-dwellings from 1m3 to 4000m3. 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. Air tightness testing for phased, zonal handover and LCHR constructions is done.

Domestic Buildings Testing as Required by Approved Document L1

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 pressure testing is compulsory, according to Approved Document L1A. A lower air permeability rate might be needed due to carbon emission requirements. 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 Tightness Testing of Commercial Buildings to Meet Approved Document L2A Requirements

Air leakage testing is the measurement of uncontrolled ventilation from a building’s fabric. The test results are inscribed using m3 per hour per square metre. Air tightness testing is required by Building Regulations. The maximum air permeability rate for a dwelling tested is 10m3/h/m2. A building will usually have to achieve a lower rate to meet the SAP or SBEM assessment. The air permeability target can be found in a building’s design-stage SAP or SBEM assessment. Uncontrolled air leakage can cause several problems. They are: infiltration of cold air, discomfort, reduction in heat, and higher CO2 emission rate.

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

We test the integrity of the smoke shaft to ensure the automatic opening ventilation is placed in the best condition. 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. We work towards air permeability targets set by the automatic-opening ventilation manufacturers that allow their equipment to operate effectively. Fans are placed in the smoke shaft to conduct an air tightness test. 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. The fixing and commissioning of the auto opening vents happen after the test is completed.

Testing Extraction Fans for Air Flow

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 test is required by law and it enables a building have a high-quality ventilation system that is efficient and removes pollutants and odours while limiting humidity in rooms, especially in kitchens and bathrooms. Part F Building Regulations also require standard intermittent extractor fans in new buildings (such as bathroom and kitchen extractors) to have their air flow rates measured on site and the results submitted to the building control body before completion.

Air Tightness Test and Building Preparation Method

Air tightness test determines the level of air permeability in a building. 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.

With residential buildings in an area, new building regulations demand that a minimum of 20% be measured for air leakage. Consistent samples are determined by the quantity of the different types of houses present during the construction of the project. We advise that all buildings undergo air pressure testing as there is a penalty for those that don’t.

What Should You Do Before Testing Your Building?

The client needs to send our test engineers the drawings of the development (plans and elevations) and target air permeability requirements. 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 prepare the site for the test, do the following:

  • Open and secure all internal doors;
  • Close all windows;
  • Switch off all mechanical ventilation systems;
  • Seal ventilation;
  • Close smoke vents;
  • Fill all drainage traps;
  • Switch off all range cookers/stoves 24 hours before testing (if applicable)

Calculating the Building Envelope

We undertake the building envelope calculations before we arrive on the site. The building envelope is the surface area of the thermal boundary of the building. The calculations, which are extracted from the drawings, are fed into our estimations when testing your building for air leaks.

Air Permeability & The Envelope Area

It is defined as air leakage rate per hour per square metre of envelope area at the test reference pressure differential of 50 pascals (50n/m2). The envelope area, or measured part of the building, is 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 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.

Evaluating a Cold Roof Envelope Area

The area of the roof and ground floor should be the same. 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.

Warm Roof Construction Envelope Area Calculation

A warm roof has the insulation running along the pitched roof rafters with an air barrier normally running parallel along the inside face of the insulation. The envelope area is the barrier between the conditioned space in the insulation and the unconditioned space outside.

Building Preparation

  • Open and secure all internal doors;
  • Close all windows;
  • Switch off all mechanical ventilation systems;
  • Seal vents;
  • Close smoke vents;
  • Fill all drainage traps; check weather conditions (wind speed, temperature, barometric pressure);

Building Test Method

Measure the weather conditions. Check the temperature, barometric pressure and wind speed. Place the fan on an aperture within the building envelope. Set up the equipment for air tightness testing. Calculate the air flow volume through the fan which equates to the air leakage. Gradually increase the fan speed from 20-25 Pa to a maximum of 55-60Pa. Record how the air pressure differs at each fan speed.

Calculating Air Leakage

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

A low leakage building that is properly ventilated, whether natural, hybrid or mechanical, is very beneficial. The benefits 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 levels of mould due to less moisture collecting in gaps and cavities. Fewer draughts and enhanced comfort From the smallest to biggest building or development, we adhere to Building Regulations Part L and Building Standards. We provide air tightness testing, consultancy, design reviews and support services on all buildings, both dwellings and non-dwellings in Kidlington. We also provide cost-effective, local service that complies with all relevant Building Standards.


Good and Best Practice Standards

Any new building has to be air tight. The 2010 Approved Document L1A of Building Regulations has made it compulsory. Reduced power usage and fuel conservation are important; that’s why the rule was put in place. Part L1A further makes it obligatory for new buildings to be tested for air permeability in line with existing building standards.

Measuring Air Permeability on Building Envelopes (Dwellings) – To Technical Standard L1

There are technical standards for air tightness test of buildings in the UK detailed by Air Tightness Test and Measurement Association (ATTMA). The technical standards give details regarding the following: BS EN 13829:2001: “Thermal Performance of Buildings. Determination of air permeability of buildings. Fan pressurisation method” and ISO 9972:2015: “Thermal performance of buildings – Determination of permeability of buildings – Fan pressurization method”. That way, testing companies use the same method.

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

Undergoing an air tightness test is compulsory for your new building, according to Part L of Building Regulations. For development with two or more buildings, three units of each dwelling type or 50% of the dwelling type should be tested. If there are no more than two new dwellings, using an assumed value of 15m3/h/m2 in the DET/TER calculations might exempt them from air tightness testing. An SAP assessor can decide which buildings can use the assumed value successfully. There are different ways that Dwellings and Non-Dwellings should be tested. ATTMA TSL1 and ATTMA TSL2 have clearly stated these. 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.

Building Regulation Requirements Part L (England and Wales)

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 is based on the performance criteria and knowledge requirements set out in the suite of National Occupation Standards (NOS) and under the requirements of the Minimum Technical Competence (MTC) document.

Air leakage testers have three levels

  • First Level – For buildings not more than 1m3-4000m3, typically single and smaller non-dwellings, a single fan is used to carry out air tightness testing.
  • The second level examines simple and complex buildings greater than 4000m3, with the exclusion of large zonal buildings and complex high-rise buildings unless a level three tester is in charge of the procedure.
  • Third Level – These experts carry out air tightness testing in large and complex high rise and phased handover buildings.

Air Leakage Test Report

Accredited testing companies issue air pressure reports. First, extraction fans are closed. Then, the details and results of the tests are written down in a report. The organisation makes sure the report meets the company and government’s requirements.

Test Outcomes

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.

Resources Air Tightness Checklist – Dwelling

Please send your design air pressure figure to us and go through the list below before we arrive at your site.

Air Leakage Pathway Checklist – Check will be done for visible leaks in the following places:

  • Windows: Check the seal beneath the sills and around the frames.
  • Doors: Check the seal around all external door surrounds (especially French doors).
  • Drainage traps: Check if they are filled with water.
  • Skirting and coving: Check above and below all skirting and coving, sealing where necessary.
  • Metre Boxes: Check all external supplies are sealed appropriately.
  • Light Fittings: Check the seal around all light fittings and switches.
  • Radiators / Fans / Heaters: Check the seal around all pipes and wires.
  • Boilers: Check the seal around the boiler supply and flue.
  • Extractor Fans: Check around the edge of the extracts, only the front of the grill can be sealed.
  • Cooker Hoods: Check the seals around all penetrations.
  • Soil pipes: Check the seal around all soil pipes and sink waste pipes especially those boxed in or behind kitchen cabinets.
  • Bath Panels: Check if all pipes behind bath panels are sealed properly.
  • Hot water tank: Check the seal around all supply pipes.
  • MVHR: Check seal around all terminals.
  • Chimneys: Open fireplaces must be sealed prior to our arrival.
  • Tumble drier extracts: Check the seal around the extract.
  • Junction between floor and wall under kitchens and baths

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.