Air Tightness Testing, Certified by AF-Acoustics, in Beddington-Corner

Air tightness testing, also called air leakage testing or air pressure testing, calculates the quantity of air escaping through openings in a building. 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. Our Air Tightness Testing certificates are registered with Air Tightness Testing and Measurement Association (ATTMA), a professional association dedicated to promoting technical excellence in all air tightness testing and air leakage measurement applications. As a certified air leakage testing company in Beddington-Corner, we are ready to provide testing services whenever you want. 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 Air Tightness Testing and Measurement Association, our air leakage test certificate is accepted as evidence for Building Regulations sign-off. We are professionals who take the time to explain the testing process, we are able to give informed advice on where problem areas may occur during testing, and how improvements can be made based on results of air pressure testing. Our customers get greater value for money spent, and our testing services are of superior 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 Explained

Air tightness testing involves calculating the quantity of air which escapes through holes in the building fabric. It can also be called air pressure testing or air leakage testing. While the normal restrained movement of air all through a building is called ventilation, the unchecked movement of air through cracks and gaps in a building is air leakage; also known as draught or infiltration. Draughts are uncontrolled ventilation. Using air tightness testing, the total air lost can be estimated. Unrestrained air movement leads to heat reduction, making the inhabitants of the building uncomfortable. The government aims to lessen the quantity of air flowing from newly built buildings. Therefore, regulations have been put in place to reduce uncontrolled ventilation from the building envelope, sustaining the right temperature conditions without using so much fuel. Air tightness testing is vital in determining the energy efficiency of a new building, air leakage and the build quality. 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, what Is It?

Air leakage is uncontrolled air movement in a building due to cracks. Air leakage is the uncontrolled movement of air into and out of a building through gaps and spaces in the building’s fabric. Also known as infiltration, it is different from ventilation, which is air that enters a building in a controlled manner. Once the atmosphere is windy, draughts infiltrate the building through holes in the fabric, leading to heat reduction and discomfort. Air leakage testing plays a significant role in the energy-saving efficacy of properties. With air tightness testing, you can be sure that the building has met the stipulated targets used for energy calculation and air tightness. All commercial buildings over 500m² and new buildings in England and Wales are mandated to test for air tightness and permeability, according to the 2006 Building Regulations.

What Is the Impact of Air Leakage?

When air escapes uncontrollably from a building, heat reduction occurs. 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. 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. There could be a decrease in the toughness and solidity of wet wooden covering due to rot.

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 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 You Should Conduct an Air Tightness Test

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 best way to reduce the quantity of fossil fuel burnt is by stopping air leakage which reduces heat loss. 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. To “Construct tight, ventilate right” is the best practice. Excess air leakage leads to moisture in the building envelope, causing large repair expenses and medical issues because of mould.

When Your Building Needs an Air Tightness Test

It is best practice to complete an air tightness test early on and then again at the final stage. 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. Selective testing has a penalty of +2m3/h/m2. If target score is 5m3/h/m2, air tightness test score will have to be 3m3/h/m2.

buildings that have not been tested are assessed for air permeability based on similar dwellings’ test scores +2m3/h/m2 at 50 Pa. Selective testing is not advisable, as it does not give a realistic picture of the air tightness of each individual building. A tested property might be a lot tighter than an untested property. Also, the penalty implemented on the untested houses make air permeability rates very difficult to achieve.

Why Pick AF Acoustics for Your Air Tightness Testing?

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

Expert information and service

Our experience in serving diverse customers in Beddington-Corner is proof of our ability to satisfy your requirements no matter the size and type of building, or your circumstance. Our air tightness experts are certified, well-mannered and competent. They’re trained to deliver a quality service, working as an extension of your project. AF Acoustics is the crew you need in Beddington-Corner to give you the best solutions.

Registered member of the Air Tightness Testing & 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 to Call Us to Test Your Building

We want to provide detailed air permeability testing in Beddington-Corner for you whenever you need it. We have responsive scheduling options. Schedule for your air leakage testing at your comfort. There won’t be delays or complications once you’ve fixed a time.

Next-day Turnaround on Test Certificate Where Possible

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.

Affordable Fees

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

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

Get Air Leakages Test for Homes and Commercial buildings in Beddington-Corner

Regardless of the size, type, or complexity of your domestic or commercial building in Beddington-Corner, 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. You can find out how much uncontrolled ventilation your building has by testing it for air leakages. 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 leakage testing is required by Approved Document L1A and L2A. 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. 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.

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. Air permeability testing is a legal requirement for constructions in Beddington-Corner. This way, they can have high energy performance, meet building regulations requirements and get signed off by building control. For your commercial building, air tightness testing will ensure your staff and clients are in a comfortable environment. 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 is a Building Regulations obligation for new buildings, commercial developments and revamped buildings. This was put into effect in 2006 after Document L was reappraised. Air tightness is referred to as 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. Samples of houses in an area and all non-domestic buildings with more than an area of to m2 must be tested, according to Part L of the Building Regulations. The highest air permeability target set is 10m3/h/m2 but your building might need a much lower one. Air leakage is vital to a building’s energy efficiency and is needed to meet Building Regulations Part L and carbon emission standards.

What Is Part F Test?

We will help you with all your Parts L and F requirements. We deliver quality air permeability and extract fan flow rate testing, and also recommend skilled experts who will handle your water calculations, SAP calculations and Energy Performance Certificates.
According to Part F, it is compulsory for a flow rate test to be conducted on all mechanical extract fans of new buildings. Building Control Body (BCB) has made a presentation of evidence of the test a compulsory aspect of a building’s sign-off process. There are 3 available methods for examining, recording and reporting the testing of extract fans. Use method 3 – the minimum benchmark method, which tests extractor fans with vane anemometers. This is our testing procedure.


What Kinds of Air Tightness Testing Services Do We Offer?

Air Tightness Testing has different tiers, depending on how complex a building is and its size. Find them below: 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. The second level examines simple and complex buildings greater than 4000m3, with the exclusion of large zonal buildings and complex high rise (LCHR) buildings. Air tightness testing for phased, zonal handover and LCHR constructions is done.

Testing of Air Permeability of Residences and Apartments, in Accordance with Document L1 Stipulations

Air leakage testing is the measurement of uncontrolled ventilation from a building’s fabric. The result is expressed as a quantity in the form of m3 per hour, per square metre of building fabric. Air leakage testing is a requirement of Approved Document L1A. A building has to achieve a lower rate to meet the carbon dioxide emission target. The required rate can be found in a building’s design-stage SAP assessment SBEM. Excess air leakage causes heat loss and discomfort due to the influx of cold air, also causing increased energy bill expense.

Air Tightness Testing of Commercial Buildings to Meet Approved Document L2A Requirements

Air tightness testing determines the extent of air leaking from a building’s envelope. The test results are inscribed using m3 per hour per square metre. Air pressure testing is compulsory, according to Approved Document L2A. The highest air permeability rate for your dwelling when tested should be 10m3/h/m2. The SAP or SBEM assessment for all buildings reduces the air permeability rate target. The required air permeability rate for each building can be found on the design-stage SAP or SBEM report for that building. Uncontrolled air leakage can cause several problems. They are: infiltration of cold air, discomfort, reduction in heat, and higher CO2 emission rate.

Testing the Smoke Shaft of Automatic Opening Vents

Smoke shaft needs to be tested because its air tightness determines the performance of the automatic opening vent fitted on it. Our professionals perform the test. 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. AF Acoustics aims for the air permeability requirements of the automatic opening vent producers, so that their product can perform optimally. An air pressure test is taken for the smoke shaft by installing a fan inside. Then the openings are sealed off in all its parts so that the shaft can be thoroughly examined. Once the test is completed and successful, the automatic opening vents are installed.

Measurement of Air Flow of Domestic Ventilation

Buildings that are well insulated and air tight are the standard for buildings. As a result, a high-quality ventilation system that is adequate and performs as required is vital. We have the capacity to test extraction rates. It is important to ensure the ventilation strategy is working effectively. This helps to remove pollutants from the air and control excess humidity, particularly in rooms such as bathrooms and kitchens. 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.

Air Tightness Test and Building Preparation Method

When a building is checked for the quantity of air flowing through the gaps in the fabric, it has undergone 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.

Gaps and cracks in the building that cause air leakage are often difficult to detect. They may be obscured by the internal building finishes. The most acceptable approach to show that a building fabric is impermeable is to identify leakage paths within it.

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 Requirements

Our test engineers require the drawings (plans and elevations) and target 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. 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)

Building Envelope Calculations

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 We use the building envelope measurements to get the right results when testing for air tightness.

Envelope Area Air Permeability

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

Air changes per hour are crucial to ventilation design, but it is only occasionally used as the base for the design or 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

Measuring if the roof area and ground floor area of a building are the same is vital. A cold roof is a roof that has its insulation in the ceiling and there’s a huge space between the insulation and rafters.

Warm Roof Envelope Area Measurement

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, found at the insulation’s warm side, is the separator between the conditioned internal aspect and the unconditioned.

Building Preparation

  • Turning off mechanical vents
  • Shutting all windows and internal doors
  • Temporarily seal vents and smoke vents
  • Filling the drainage stops

Process for Testing the building

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. Record the air volume flow through the fan (this equals the air leaking through the building envelope). 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

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. Testing for Air Permeability and Following Part L Building Regulations

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: Lower heating bills due to less heat loss, with potentially smaller requirements for heating and cooling equipment capacities Your ventilation system will operate in a better way Lower probability of mould because moist air won’t condense in the openings in the building envelope. Fewer draughts, causing more comfort Our air leakage tests are conducted according to building regulations and targets, whether we’re testing a small dwelling or big commercial development. Our services include: air pressure testing, support services, re-examining designs and consultancy for all buildings in Beddington-Corner. We are cost effective and adhere to all building regulations.


Best Practice Procedures

Building Regulation Part L1A 2010 stipulates that all new buildings must have low air permeability. Reduced power usage and fuel conservation are important; that’s why the rule was put in place. The dwelling should be tested for air permeability in line with existing building standards, as stipulated by Approved Document Part L1A.

Air Tightness Testing of Dwellings That Meet Technical Standard L1L1

Certain technical standards are to be employed during air pressure test in the UK, as specified by ATTMA, building regulations and other documents. 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

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. 50% or 3 units of each dwelling type should undergo an air leakage test in the case of an area with two or more dwellings. A development with only two dwellings may not undergo a test if a suggested value of 15m3/h/m2 is stipulated in the DER/TER measurements. 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. Non-Dwellings and residential buildings are required to test for air leakage. Non-dwellings with a typical floor area less than 500m2 may be exempt. Where testing is not carried out, an assessed air permeability of 15 m3/h/m2 must be used in calculations.

Part L Building Regulations Standards for 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. Minimum Technical Competence (MTC) and National Occupation Standard (NOS) documents are the basis for the scheme.

Air tightness testers can be divided into three categories

  • Air tightness testing for single buildings and smaller non-dwellings not more than 4000m3 is done with a fan.
  • 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.
  • Level 3: These are air tightness experts who can cover large, complex and or high-rise buildings and or phased handover or zonal compartmentalisation.

Air Tightness Test Report

Accredited testing companies issue air pressure reports. Temporary sealing of extraction units will be done by the tester; all test results will be noted, and a shortened form report will be written which will include the findings of the test. The report is in line with the company’s testing process set by government regulations and all relevant governing bodies.

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. We make sure our report has the name of the building, customer, address and tester. Where applicable, we will identify pass or failure of your building and provide recommendations for any remedial action or improvement to the building if any further testing is required.

Resources Air Tightness Checklist – Dwelling

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

Temporarily cover the following;

  • Trickle Vents: Close them.
  • MVHR Terminal/Extract Fans: Switch off and seal temporarily.
  • Air Bricks and Chimney Flues: Cover temporarily.
  • Cooker Hoods: Seal off from the inside or outside.

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.