ATTMA Licensed Air Tightness Testing in St-Lukes

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.

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. We register our air tightness certificates with the Air Tightness Testing and Measurement Association (ATTMA), an organisation that encourages proper air leakage applications and promotes quality air tightness screening. AF Acoustics, a licensed air tightness testing company, is available to provide testing services at your request. Our address is St-Lukes. 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. 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. AF Acoustics provides services that are cost effective and of high standard.

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 It Means

Air tightness testing is a method of measuring the extent to which air is lost through leaks in the building fabric. Other names for air tightness testing are air leakage testing and air pressure testing. Air leakage is the uncontrolled flow of air through gaps and cracks in the fabric (often referred to as infiltration or draughts) and not ventilation, which is the controlled flow of air in and out of the building. Air leakage is uncontrolled ventilation. Air tightness testing is the approved method for gauging the entire air that has leaked through a building fabric. Once too much air escapes, heat reduction occurs, causing the temperature of the building to drop to a level that isn’t comfortable for those residing in it. As Government strives to reduce CO2 emissions from new buildings, building regulations now place greater emphasis on reducing air leakage from the building envelope. This reduces fuel consumption and CO2 emissions. 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. Incorporating this at the beginning of the construction process makes the development more cost effective and energy efficient.

What Air Leakage Is

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. Because of the nature of air leakage, excessive air infiltration might occur in a building when the weather is windy and chilly. This results in loss of warmth and an unpleasant cold draughts. 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. In 2006, air tightness of newly constructed buildings and non-dwellings with a floor area over 500m² became compulsory in England and Wales.

Air Leakage’s Resulting Outcomes

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. As cold seeps inside, warm moist air escapes through the cracks and gaps in the building. Some of it settles within the building’s fabric. 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 overlay or framing can decay, decreasing its durability.

Over time, any of these conditions can cause structural damage.
Air leakage can also cause these problems:

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

These effects can be mitigated by controlling the circulation 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. To get rid of pollutants, water vapour and moisture odour, the building must be well ventilated.


Why Should We Do an Air Tightness test?

Air tightness is a key factor in building energy efficiency, and is a part of government-led initiative to combat climate change through improvements in building energy performance. Fossil fuel is burnt to heat up a building. This leads to a discharge of carbon dioxide which increases global warming. The best way to reduce the quantity of fossil fuel burnt is by stopping air leakage which reduces heat loss. 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 Is an Air Tightness Test Needed?

It is best practice to complete an air tightness test early on and then again at the final stage. The results of the test can affect a building’s energy ratings because they play a part in SBEM and SAP calculations. Larger residential developments do not require testing to be completed on each individual property, instead, testing is undertaken on the different dwelling types within the development. Selective testing has a penalty of +2m3/h/m2. If target score is 5m3/h/m2, air tightness test score will have to be 3m3/h/m2.

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.

Why You Should Choose AF Acoustics for Your Air Tightness Testing

With AF Acoustics, homes and businesses in St-Lukes have been getting quality air tightness testing. We come highly recommended by our clients because of the following guarantees.

Service and knowledge

Our vast experience in serving a variety of clients in St-Lukes guarantees we have the expertise to satisfy your needs regardless your unique circumstances, type or size of property. 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. Our knowledgeable and dependable air testing experts will provide lasting solutions to your problem. Call AF Acoustics for your air tightness testing.

Registered member of the Air Tightness Testing & Measurement Association (ATTMA)

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.

Responsive scheduling

We want you to be able to access comprehensive air tightness testing in St-Lukes 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.

Test Certificates Get to You on the Next Day, Where Feasible

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.

Competitive Pricing

AF Acoustics, a small business with low overheads, offers one of the best prices in St-Lukes and guarantees professional services.

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

Air Tightness Tests for Any Kind of building in St-Lukes

Regardless of the size, type, or complexity of your domestic or commercial building in St-Lukes, 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.

Air tightness testing is recommended by Approved Document L1A and L2A. The maximum air permeability rate is 10m3/h/m2. The carbon discharge requirement for all buildings reduces the air permeability rate target. This target can be found in a building’s design-stage SAP assessment or SBEM. Excess air leakage causes heat loss, greater carbon dioxide discharge and can make occupants uncomfortable due to the influx of cold air. It also causes wind washing and thermal bypassing, resulting in lower energy performance. Infiltration/exfiltration is the effect of air pressure difference. Warm air rises while cold air falls. The warm air within a building rises and air pressure at the base falls; this results in air coming in through doors, windows and leakage points. To get signed off by building control in St-Lukes, all buildings are to undergo air tightness testing and measure up to the required energy efficiency standards. Buildings where businesses are conducted will not cause discomfort to employees and clients because they have the legal air permeability rating. It will also help you reduce the cost of maintaining heating or cooling in your commercial building, making it more productive.

What Is Part L Test?

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. Other names for air tightness are air permeability rate or leakage rate. Air leakage can occur through gaps, holes and cracks in the fabric of the building envelope (service penetrations, wall/roof junctions, etc), which are not always visible. The Building Regulations (Part L) demand that a selected group of different kinds of residential constructions and all non-domestic buildings greater than 500m2 perform air leakage tests. Part L has also set a maximum air permeability target rate of 10m3/h/m2, but a building usually needs lower levels. Air tightness is important for meeting the Building Regulations Part L standards, exceeding requirements for low carbon buildings, and overall energy efficiency.

What Is Part F Test?

We can complete all your Part F and Part L testing 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.
New buildings should ensure that all mechanical extract fans are tested for flow rate, as stipulated by Part F of the Building Regulations. The Building Control Body (BCB) has to see the results of the test as part of its sign-off procedure. Examining, documenting and submitting reports of extract fans’ test can be done using three methods. Using a vane anemometer, our testing procedure follows Method 3 – The minimum benchmark method.


Forms of Air Pressure Testing Services We Provide

There are several levels of air leakage testing based on the kind, size and multifaceted aspects of a dwelling. Here they are: Level One: Testing for the air pressure of single buildings and smaller non-dwellings of 4000m3 gross envelope volume and below, a single blower door fan is used. Level 2: Air pressure testing for simple and complex buildings larger than 4000 m³ gross envelope volume which does not include large and complex, high rise (LCHR) buildings, and phased handover/zonal buildings. Level Three: At this level, tests for the air pressure of high rise (LCHR) buildings and phased handover/zonal buildings.

Approved Document L1 Air Pressure Testing of Houses

Air pressure testing, involves the calculation of air escaping through openings in a building. The result of the air leakage test is expressed as a quantity of air leakage (mm3 per hour) per square metre of building envelope. Air pressure testing is compulsory, according to Approved Document L1A. The carbon discharge requirement for all buildings reduces the air permeability rate target. The required air permeability rate for a dwelling can be found on the design-stage SAP report for that dwelling. Excess air leakage causes heat loss and discomfort due to the influx of cold air, also causing increased energy bill expense.

Testing of Air Permeability of Commercial Dwellings, in Accordance with Document L2 Stipulations

Air pressure testing involves the calculation of air escaping through the openings in a building. The result is expressed as a quantity in the form of air pressure (m3 per hour) per square metre of building fabric. Document L2A of Building Regulations declares air leakage testing to be mandatory. The 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 required air permeability rate for each building can be found on the design-stage SAP or SBEM report for that building. Air leakage causes heat loss, increased energy bills, greater CO2 emissions, and an uncomfortable atmosphere for inhabitants due to draughts.

We Test Your Automatic Opening Vent’s Smoke Shaft

To ensure that the auto opening vent will perform optimally when fitted and commissioned, we test the smoke shaft to verify its air tightness. When there is a fire, the auto opening vents play an important part in expelling smoke in multi-storey buildings. An air tight shaft creates sufficient pressure difference and ensures that the fans and vents perform properly to draw out smoke from a dwelling and save its occupants. 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 conducted using a fan installed in the shaft. 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.

Air Flow Measurement of Domestic Ventilation (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 test fan 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.

Precise Air Pressure Test and Building Procedure

Air tightness tests calculate the level of air leakage a building has and if it is excessive. If the rate of air pressure is good, the energy performance of a building will be high and the inhabitants will be comfortable.

External claddings and the internal building finishes might obscure a gap in the building fabric. This makes it hard to notice and can results to potential air leakage. 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. We recommend that all buildings be tested as those that aren’t are penalised.

What You Need to Do Before Undertaking the Test

Our test engineers require the drawings (plans and elevations) and target air permeability requirements of your building before taking the test. The test engineers would like to have the information needed for the test before coming to your development. Our air leakage test is done between 30 and 60 minutes, and the wind speed is a maximum of 6m/s. To prepare the site for the test, do the following:

  • Turning off all range stoves and cookers (if applicable)
  • Turning off mechanical vents
  • Shutting all windows and external doors
  • Sealing ventilation grids and smoke vents
  • Filling the drainage stops

Measuring the Building’s Envelope

We take the building envelope calculations before the test. A building envelope is the boundary between the conditioned and unconditioned environment of a building. The calculations are taken from the drawings. These are then incorporated into our calculations when we air test the property.

Air Permeability & The Envelope Area

Air permeability is calculated at air leakage rate per square metre of envelope area. In relation to air permeability, the air envelope area is the total area of the measured part of the building without subtracting from the area of the junction of internal walls, or floors and ceilings. The envelope area of a terraced house includes the party walls while that of a flat in a multi-storey building includes shared ceilings, walls and floors.

Air Exchange Rate

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.

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

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 readiness

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

Process for Testing the building

Check weather conditions (wind speed, temperature, barometric pressure); Place the fan on an aperture within the building envelope. Set up testing equipment. Using the fan, measure the air flow volume, from the building fabric. Gradually increase the fan speed from 20-25 Pa to a maximum of 55-60Pa. At each fan speed, note the differences in air pressure in all the parts of the building.

Evaluating Air Leakage

Our air leakage measurement involves picking out the gaps where air leakage takes place, recording the test information, sending results to customers in a technical report and advise clients on repair methods in the case of a test failure. 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: The occupants will pay less for heat because less heat is lost and they won’t need equipment with high heating capacities. A functional ventilation system Lower probability of mould because moist air won’t condense in the openings in the building envelope. Fewer draughts and enhanced comfort From a single dwelling to the largest commercial development, we offer stress-free compliance measurements to Part L Building Regulations and Building Standards. Our services include: air pressure testing, support services, re-examining designs and consultancy for all buildings in St-Lukes. We are cost effective and adhere to all building regulations.


Good and Best Practice Standards

Building Regulation Part L1A 2010 stipulates that all new buildings must have low air permeability. Less fuel and power are consumed by buildings. Part L1A has demanded that all new dwellings be tested for air leaks in line with other regulations.

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). 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.

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

Building Regulation for England and Wales, Part L 2010

Approved document L1A has made it compulsory for all new buildings to be tested for air leaks. For development with two or more buildings, three units of each dwelling type or 50% of the dwelling type should be tested. If the development has one or two dwellings only, an air tightness test might not be taken if the DET/TER calculations assume a value of 15m3/h/m2. Your SAP assessor will be able to confirm if this is the case for your dwelling. The method for testing required by the building regulations is stated in ATTMA TSL1 (for dwellings) and ATTMA TSL2 (for non-dwellings). Non-Dwellings and residential buildings are required to test for air leakage. If your building has added an estimated assessed rate of 15 m3/h/m2 in its calculations or its useful floor space is less than 500 m2, it may not have to take the test.

Building Regulations Part L (England And Wales)

An industry-wide competence scheme endorsed by the government is carried out by the ATTMA. It was launched in January 2015 as stipulated in the Technical Standard L1 and L2. 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

  • A single fan is the instrument used for the first level to examine single buildings and smaller non-dwellings from 1m3 to 4000m3.
  • Level 2: Testers can test all buildings except large, complex and or high-rise buildings and or phased handover or zonal buildings unless part of a team managed by a level 3 tester.
  • The third level expert tests big and complex zonal and phased buildings and complex high-rise buildings.

Report on Test for Air Permeability

Test reports are issued by registered and licensed air tightness companies who test buildings of different sizes and complexities. The testing companies seal extraction fans. After the test has been completed, they record test findings and results in a report. The report adheres to the company’s methods and all standards and requirements of Building Regulations.

Test Outcomes

AF Acoustics will ensure the test result is written in accordance with the test standard requirements, identify any deviations from the relevant standards within the report and check air tightness against target value. We make sure our report has the name of the building, customer, address and tester. If a building fails the test, we provide remedial suggestions before a retest is carried out.

Resources Air Tightness Checklist – Building

Before our test engineers arrive at the site, please adhere to what is written below and send the required air tightness target of your dwelling that is in the design to us.

Air Permeability Pathway Checklist – Use this checklist to make sure you are ready for the test. Ask yourself, “Have I sealed any visible opening?” Check the following appliances.

  • Junction between floor and wall under kitchens and baths
  • Extract fans
  • Hoods of cookers
  • Bath panel
  • Windows
  • Metre boxes
  • Hot water tank
  • Chimney
  • Boilers
  • Radiators, fans and heaters
  • Skirting and coving
  • Tumble drier extracts
  • MVHR
  • Soil panel
  • Drainage traps

We Provide Temporary Sealing – the following should be temporarily sealed during the test;

  • Trickle Vents: Should be closed.
  • Extractor Fans / MVHR terminals: All extracts should be temporarily sealed (Please ensure these are off before sealing).
  • Cooker Hoods: Should be sealed from the outside or inside.
  • Chimney Flues and Air Bricks: Should be temporarily sealed.

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.