Aldgate Air Tightness Testing Certified by AF-Acoustics

Air tightness testing determines the quantity of air coming out of cracks in a building. It is also known as air permeability testing or air leakage testing. Since Approved Document L was reviewed in 2006, air tightness testing has become an essential part of building regulations for newly completed and rehabilitated buildings.

Air leakage occurs through any opening in the building envelope and can affect a building’s energy performance, this has been addressed by changes to the building regulations. AF Acoustics certificates are certified by Air Tightness Testing and Measurement Association (ATTMA). ATTMA is an association of specialists that concentrate on promoting the best air tightness measurements and air permeability testing techniques. We are a dedicated and approved air leakage testing service in Aldgate and we can provide air permeability measurement whenever you require. You can also call or email us for any of these services:

  • Assessments
  • Consultancy
  • Part F mechanical extract fan flow rate testing.

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. If you want specialist air pressure testing services in Aldgate, AF Acoustics’ tightness testing services will

  • Describe the process to you,
  • Highlight possible problem areas that might occur during testing,
  • Conduct the air tightness test, and
  • Give advice on improvements based on the outcome of the test.

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 – What It Means

Air tightness testing is a technique whereby a newly constructed building is evaluated and the quantity of air leaking through is measured. Air tightness testing is also known as air pressure testing or air leakage 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. When too much air leaks through a building’s fabric, heat loss occurs, making the occupants 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. Calculating the emission of air from a building’s fabric, establishes the energy efficiency of the building. Most building designs take air pressure into account at the beginning of construction in order to have an air-tight envelope and measure up to the required standards. A building that is air tight A building that is air tight is more economical and ensures less drafts ALS energy efficient.

Air Leakage, what Is It?

Air leakage is where air enters and leaves a building uncontrollably through cracks and holes in the building fabric. Also called infiltration, it differs from ventilation which is the regular, planned and restrained flow of air into a building. As air leakage is uncontrolled, too much air may enter the house during cold or windy weather, leading to excessive heat loss and uncomfortable 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 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 causes heat loss. During windy or cold weather, the infiltration of uncontrolled air through cracks in a building envelope occurs, leading to heat reduction. Movement of moist air into cavities in other parts of the building also occur. This process is called exfiltration. Once the moist air reaches the colder internal layer of the wall structure, the vapour in it condenses and forms droplets of liquid, which drawn into building materials and can potentially start a multitude of structural problems. Wet wooden framing or sheathing can rot and break down, diminishing its strength.

Over time, any of these conditions can cause structural damage.
The inhabitants become uncomfortable because of chilly homes, heating expenses increase and more CO2 is emitted due to the additional heat required.

The key to minimising the damage potential of moisture is effectively managing the flow of air into and out of the building. A properly installed air barrier minimises air leakage, which, in turn, minimises the potential for water vapour to condense on vulnerable wall structures. Passive or active ventilation is required to reduce water vapour, moisture odour and pollutants.


Why is an Air Tightness Test Important?

Air tightness is an important factor in a building’s energy efficiency and is part of government’s plan to battle environmental change by regulating the energy performance of buildings. Environmental change caused by carbon dioxide emissions and global warming is partly aided by the burning of fossil fuels to generate heat. The best way to reduce the quantity of fossil fuel burnt is by stopping air leakage which reduces heat loss. Poor degrees of ventilation and high levels of uncontrolled air leakage encourage mould growth and excessive moisture. This could potentially cause medical issues. A great option would be to build tight and ventilate right. High degrees of air leaks cause huge problems such as expensive remedial work on the building and medical problems.

When Do I Need 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 can affect a building’s energy ratings because they play a part in SBEM and SAP calculations. Individual property is not tested in a large residential development. The test is done on different types of houses within the area. Once every building in the residential development is not tested, the expected test result would have to be lowered by 2m3/h/m2. If 5m3/h/m2 was your target score, you must achieve 3m3/h/m2.

If your building has not been pressure tested, its assessed air permeability would be the average score of buildings like yours in the area +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 Aldgate. Because of the following guarantees of working with us, we are highly endorsed by our clients.

Helpful service and information

Our experience in serving diverse customers in Aldgate is proof of our ability to satisfy your requirements no matter the size and type of building, or your circumstance. 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. AF Acoustics is the crew you need in Aldgate to give you the best solutions.

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.

Picking a Time for Your Air Permeability Test

You can access our complete air tightness test in Aldgate at anytime. We offer responsive scheduling. Schedule for your building to be tested at your convenience. We guarantee no delays or complications regarding scheduling.

Next-day Turnaround for Certificates

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.

Competitive Charges

AF Acoustics offers competitive fees in Aldgate. 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

Get Air Leakages Test for Homes and Commercial buildings in Aldgate

Regardless of the size, type, or complexity of your domestic or commercial building in Aldgate, 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 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 building fabric.

Approved Document L1A and L2A demands that buildings take tests for air leaks. Although your building is required to have a rating result of 10m3/h/m2, the actual result might have to be lower than that due to carbon emission requirements. You can find the required air permeability rate of your building in its design-stage SAP assessment or SBEM. Excessive air leakage causes discomfort due to heat reduction and carbon dioxide discharge. It also creates convective loops within a building’s internal structure, leading to energy loss. Warm air within a heated building rises and lowers the pressure at the building’s base to draw in air through the openings in the building fabric, leading to exfiltration or infiltration. To get signed off by building control in Aldgate, 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. The company also gets reduced heating and cooling costs and higher productivity rates.

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. Air tightness is also called air leakage rate or ‘air permeability’ rate. Air leaks through gaps and spaces in the building fabric such as service penetrations, walls and roof junctions. Sometimes, this is not obvious to occupants. Part L of the Building Regulations requires that all commercial buildings greater than 500m2 undergo air tightness testing and a selection of residential buildings in a development be tested. Part L has also set a maximum air permeability target rate of 10m3/h/m2, but a building usually needs lower levels. Air leakage is vital to a building’s energy efficiency and is needed to meet Building Regulations Part L and carbon emission standards.

A Description of Part F Test

All your Part L and Part F testing requirements can be met by us. 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.
According to Part F, it is compulsory for a flow rate test to be conducted on all mechanical extract fans of new buildings. The Building Control Body (BCB) has to see the results of the test as part of its sign-off procedure. Extractor fans can be tested and recorded, and test reports submitted using 3 methods. AF Acoustics test process is the third method. It uses a vane anemometer and is called the minimum benchmark method.


Types of Air Leakage Testing Services We Offer

There are several levels of air leakage testing based on the kind, size and multifaceted aspects of a dwelling. Here they are: A single blower door fan is used for air tightness testing for single buildings and smaller non-dwellings not more than 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.

Approved Document L1 Air Pressure Testing of Houses

Air tightness testing determines the extent of air leaking out a building’s envelope. The result is written as m3/h/m2 – (m3 per hour) per square metre of building envelope. Air tightness testing is required for new builds. Your building may need a lower rate to meet the CO2 discharge target. To get your building’s required air permeability rate, check its design-stage SAP assessment SBEM. An excessive amount of air leakage results in greater energy expenses, heat reduction and carbon dioxide emissions.

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

The measurement of air emitted by a building is tested to ascertain air permeability rating. The result is expressed as a quantity in the form of air pressure (m3 per hour) per square metre of building fabric. 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. Your building may need a lower air permeability 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. 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

We provide smoke shaft tests to make sure it is air tight enough to let the automatic opening ventilation work optimally when it’s installed and commissioned. Automatic opening vents are crucial during fire emergencies in storey buildings, as they clear out smoke from the buildings. For it to expel smoke from a building and keep the occupants safe during emergencies, the shaft must be air tight enough to create substantial pressure difference. 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. 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. Smoke shaft tests occur before installing and commissioning automatic opening ventilation.

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 have the capacity 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 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.

Explicit Test and Building Preparation Process

When a building is checked for the quantity of air flowing through the gaps in the fabric, it has undergone an air tightness test. Improving the air tightness of a building not only enhances the comfort of the occupants, but can also increases the building’s energy efficiency.

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 only satisfactory way to show that a building fabric is airtight is to detect and measure leakage paths within the building fabric.

At least 20% of different kinds of dwellings in a development have to be tested, according to new regulations; but the reliability of the sample from this type of testing is determined by the types of buildings in the development. We recommend that all buildings be tested as those that aren’t are penalised.

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. In preparing the site to create an air-tight environment:

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

Measuring the Building’s Envelope

We take the building envelope calculations before the test. The building envelope, is the physical barrier between the exterior and interior of a construction. The measurement is obtained from the construction drawings, and put in our calculations to conduct the test.

Air Permeability & The Envelope Area

Approved Document L1A Conservation of Fuel and Power in New Dwellings (2010) defines air permeability as “air leakage rate per hour per square metre of envelope area at the test reference pressure differential of 50 pascals (50n/m2)” and envelope area as “the total area of all floors, walls and ceilings bordering the internal volume that is the subject of the pressure test. This includes walls and floors below external ground level. Overall internal dimensions are used to calculate this envelope area and no subtractions are made for the area of the junctions of internal walls, floors and ceilings with exterior walls, floors and ceilings.”

Air Change Rate

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. Residential ventilation rates are calculated based on area of the residence and number of occupants.

Cold Roof Construction Envelope Area Calculation

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 is a roof system where the insulation is fixed along the rafters with an air barrier inside the insulation. The envelope area is the barrier between the conditioned space in the insulation and the unconditioned space outside.

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

Check all weather conditions such as temperature, wind speed and barometric pressure. Connect a fan to an opening, like the door, in the building fabric. Ensure all the testing equipment is ready. Using the fan, measure the air flow volume, from the building fabric. Slowly raise the fan speed from 20-25Pa to 55-60Pa. Note the difference in air pressure in several parts of the building at each fan speed.

Measuring air leakage

We analyse the air tightness test data, point out any air leakage path and send a report to clients. If the building fails the test, we suggest remedial measures to the client. Testing for Air Permeability and Following Part L Building Regulations

The positive effects of an air tight building with efficient ventilation (natural, mechanical or a combination) cannot be underestimated. Here they are: Reduced heating expenses because of lower heat loss, with less need for equipment that has high heating ability. A functional ventilation system Lower levels of mould due to less moisture collecting in gaps and cavities. You won’t experience much discomfort because there will be fewer draughts. Be assured that you’ll get a test that meets all the regulations and standards no matter how big or small your building is. They also ensure that you spend less money. Here are the services we provide:

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

Best Practice Processes

Building Regulation Part L1A 2010 stipulates that all new buildings must have low air permeability. The regulation is focused on the conservation of fuel and power usage. Part L1A states that new dwellings should be tested for air tightness in accordance with existing regulations.

Testing for Air Tightness in Building Fabrics of Dwellings to Adhere to Technical Standards L1

There are technical standards for air tightness test of buildings in the UK detailed by Air Tightness Test and Measurement Association (ATTMA). BS EN 13829:2001 and ISO 9972:2015 are clarified by the technical standards. The technical standards provide rules that ensure testing organisations get the same results from the same kind of tests and are based on BS EN 13829 “Thermal Performance of Buildings. Determination of air permeability of buildings. Fan pressurisation method” and ISO 9972:2015, “Thermal performance of buildings – Determination of permeability of buildings – Fan pressurization method”.

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

Building Regulation Part L 2010 (England and Wales)

Test for air permeability must be conducted on your new constructions. This is stated in Approved Document L1A. For developments of two or more dwellings, an air leakage test should be carried out on the three units of each dwelling type; or 50% of all instances of that dwelling type. For developments where no more than two dwellings are constructed, it may be possible to avoid the need for any pressure testing by using an assumed value of 15m3/h/m2 within the DER/TER calculations. 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). Air leakage testing is required on all residential developments (this may be a sample of units) and certain Non-Dwellings. 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 Regulations for England and Wales, Part L

ATTMA has a scheme for air leakage test organisations, which commenced in January 2015. The scheme was approved by the government and is stated in Technical Standard L1 and L2. It mirrors the operation standards and skill requirements set by the National Occupation Standard (NOS) and the Minimum Technical Competence (MTC) document.

Testers can be divided into three types

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

Air Leakage Test Report

Authorised companies, who test buildings of different types, sizes and complexities, give air tightness reports. First, extraction fans are closed. Then, the details and results of the tests are written down in a report. The report adheres to the company’s methods and all standards and requirements of Building Regulations.

Results of the Test

Our test and subsequent results are conducted and written to meet standard requirements, highlight any deviation from the standards and crosscheck air pressure values against target values. We make sure our report has the name of the building, customer, address and tester. Where it’s needed, we will identify if your building passed or failed the test and suggest ways to repair the building envelope before a retest is done.

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 Leakage Pathway List –Ensure you thoroughly check the following equipment. Fill up drainage traps. Here are the pieces of equipment to cover, fill or seal:

  • Extract fans
  • Hoods of cookers
  • Drainage traps
  • Metre boxes
  • Boilers
  • Radiators, fans and heaters
  • Hot water tank
  • Chimney
  • Air bricks
  • Skirting and coving
  • Bath panel
  • Tumble drier extracts
  • MVHR
  • Soil panel

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.