Hoxton Air Tightness Testing, Licensed by AF-Acoustics

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.

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

Because we are ATTMA members, any air tightness certificate we issue shows that the construction has met building regulation standards. We don’t just provide air tightness testing. We describe the process thoroughly, give expert advice on areas that could be problematic during testing, and suggest improvements based on the air permeability rating of the building. Our goal is always value for money and customer satisfaction. We are professionals and our services are of the highest quality.

Our Guarantee

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

Air Tightness Testing Explained

When a building is assessed during an air tightness test; the internal thermal envelope of the building is examined for leakages and the quantity of air passing through it. Air leakage and air pressure are also used in place of air tightness. 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 tightness testing evaluates the complete air leakage a building has in every gap available. The air leakage is known as uncontrolled ventilation. Unrestrained air movement leads to heat reduction, making the inhabitants of the building uncomfortable. Regulations now concentrate on minimising air leakage from the building envelope thereby reducing the amount of fuel burned for maintenance. This helps reduce carbon dioxide 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. 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. When the circulation of air is properly monitored and bridled, ventilation has occurred. Another name for air leakage is infiltration. It may cause uncontrolled influx of air during frosty and windy weather. This reduces the temperature of the building, making the occupants uncomfortable. 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. 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 heat reduction. During windy or cold weather, the infiltration of uncontrolled air through cracks in a building envelope occurs, leading to heat reduction. The infiltration of chilly air causes exfiltration, making warm air within the building escape through the spaces in other parts of the building. When moist air hits a cooler surface within a wall structure, water vapour in the air can condense and collect inside these spaces. Moisture can then be absorbed in building materials and cause serious defects. The strength of the outer wooden covering is drastically reduced because it is wet.

Over the years, these problems can damage the building’s structure.
Other impacts include:

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

The most effective method of lessening the damage caused by moisture is to control the flow of air into and out of the building. Adequately installed air barriers minimise air leaks and the probability of vapour condensing and diffusing into the building’s structure. Correct ventilation, whether passive or active, ensures fresh air circulates through the building, eliminating water vapour, moist odour and polluting substances.


Why Should We Do an Air Tightness test?

The energy performance of a building is determined by how air tight it is. Energy performance affects CO2 released from buildings. As a result, air tightness testing is a method government has devised to regulate climate change. Heating buildings contribute to global warming and CO2 emissions, since fossil fuels are used to create heat. When air leakage is controlled, heat loss and energy used by the heating system are reduced. Poor degrees of ventilation and high levels of uncontrolled air leakage encourage mould growth and excessive moisture. This could potentially cause medical issues. To “Construct tight, ventilate right” is the best practice. The result of uncontrollable air moving into the building fabric could be health problems and costly repairs.

When Do I Need an Air Tightness Test?

Best practice says that air tightness tests should be carried out early in construction and after the final phase. The test results are part of SBEM and SAP calculations, therefore they influence the total energy ratings of new buildings. 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. This type of testing attracts a penalty of +2m3/h/m2, consequently, if the target result is 5m3/h/m2, a lower score of 3 would have to be attained.

buildings that have not been tested are assessed for air permeability based on similar dwellings’ test scores +2m3/h/m2 at 50 Pa. Selective testing is not 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 You Should Choose AF Acoustics for Your Air Tightness Testing

Numerous businesses and home owners have been aided by AF Acoustics air tightness testing proficient skills in Hoxton. Because of the following guarantees of working with us, we are highly endorsed by our clients.

Great service and expertise

Our experience in serving diverse customers in Hoxton 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. Our personnel will use their expertise to provide lasting solutions. Contact AF Acoustics in Hoxton –the right team for your building.

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

We are registered members of the Air Tightness and Measurement Association (ATTMA). ATTMA encourages proper air leakage applications and promotes quality air tightness screening, and has recognised our impeccable professional services.

When to Call Us to Test Your Building

Our comprehensive air permeability testing in Hoxton is available. We offer responsive scheduling. Schedule for your building to be tested at your convenience. We won’t make you wait or make the process complicated.

Next-day Turnaround for Certificates

AF Acoustics offers trustworthy and expert services. We know that clients want to receive their test results quickly. As a result, we endeavour to deliver test certificates by the next day.

Affordable Prices

AF Acoustics fees are lower since we’re a company with low overheads. Our services are professional and we offer affordable prices in Hoxton.

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

Air Permeability Testing for Different Kinds of Commercial and Domestic Dwellings in Hoxton

We conduct air permeability tests on residential and commercial buildings of all sizes and types. After the test, an ATTMA certificate is given to you. You can find out how much uncontrolled ventilation your building has by testing it for air leakages. The results are registered as The test results are described as m3/h/m2 – (m3 per hour) per square metre of building.

Air leakage testing is required by Approved Document L1A and L2A. 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. Exfiltration/infiltration of air is caused by the difference in air pressure inside and outside the building. Lower pressure occurs as warm air rises and brings air inside through any available opening. In Hoxton, the law demands that all new buildings be tested for air pressure before they can be approved and signed off by building control. This enables dwellings achieve energy efficiency standards. Buildings where businesses are conducted will not cause discomfort to employees and clients because they have the legal air permeability rating. Heating and cooling expenses are also reduced and the environment is more productive.

Part L Test Explained

In 2006, Approved Document L was reviewed and building regulations for air permeability became tighter. The air tightness test is presently a requirement for new buildings and reconstructions. Other names for air tightness are air permeability rate 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. 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. The highest air permeability target set is 10m3/h/m2 but your building might need a much lower one. Air leakage affects the building’s energy performance and is required to meet Building Regulations Part L and measure up to the standard for low carbon buildings.

What Is Part F Test?

We will ensure that you exceed all the Parts L and F standards. 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.
New buildings should ensure that all mechanical extract fans are tested for flow rate, as stipulated by Part F of the Building Regulations. Evidence of this test must be passed to the Building Control Body (BCB) as part of their sign-off procedure. There are three alternative methods which can be followed to test, record and report the testing of extractor fans. Using a vane anemometer, our testing procedure follows Method 3 – The minimum benchmark method.


What Kinds of Air Tightness Testing Services Do We Offer?

There are different levels of air tightness testing established from the size and complexity of a building. An overview of each is provided below: First Level – For building 1m3-4000m3, single and smaller non-dwellings, a single blower door fan is used to carry out the test. Level Two: Single and multifaceted buildings 4000m3 gross envelope volume and above are tested for air pressure. High rise (LCHR) buildings and phased handover/zonal buildings are excluded from this level. Level Three: At this level, tests for the air pressure of high rise (LCHR) buildings and phased handover/zonal buildings.

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

The measurement of air emitted by a building is tested to determine air permeability rating. The result is written as m3/h/m2 – (m3 per hour) per square metre of building envelope. Part L1A of Building Regulations stipulates that such tests be conducted. A lower air permeability rate might be needed due to carbon emission requirements. The design-stage SAP assessment SBEM of a construction records its required air permeability rate. Excess air leakage causes heat loss and discomfort due to the influx of cold air, also causing increased energy bill expense.

We Offer Air Leakage Testing of Business Buildings to Meet Approved Document L2A Standard

An air leakage test is a test to determine the level of uncontrolled air flow through gaps or cracks in the fabric of a building. The air leakage test result is written as m3/h/m2 – (m3 per hour) per square metre of building. Air pressure testing is compulsory, according to Approved Document L2A. Each building tested must achieve a maximum air permeability rate of 10m3/h/m2. In order to comply with the SAP assessment, it may be necessary to achieve a lower air permeability rate. The required air permeability rate for each building can be found on the design-stage SAP or SBEM report for that building. Excess air leakage causes heat loss, greater carbon dioxide discharge and influx of cold air.

We Test Your Automatic Opening Vent’s Smoke Shaft

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. Automatic opening vents are crucial during fire emergencies in storey buildings, as they clear out smoke from the buildings. The performance of the fans and vents depends on the air tightness of the shaft. Air tight shafts have enough pressure difference to extract smoke and save people inside a building during fire emergencies. We work towards air permeability targets set by the automatic-opening ventilation manufacturers that allow their equipment to operate effectively. Fans are placed in the smoke shaft to conduct an air tightness test. Then the openings are sealed off in all its parts so that the shaft can be thoroughly examined. The fixing and commissioning of the auto opening vents happen after the test is completed.

Air Flow Measurement of Domestic Ventilation (extraction fan testing)

With the legal requirement for buildings that have the right quantity of air pressure, adequate ventilation that is suitable, effective and of high quality has become crucial. We evaluate 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. The air flow rates of all intermittent extractor fans, which are to be installed during the building process, are to be tested and the results submitted to the Building Control Body before work is completed.

Particular Test and Building Readiness Operation

When a building is checked for the quantity of air flowing through the gaps in the fabric, it has undergone an air tightness test. The air tightness of a building improves its energy efficiency and internal environment.

Causes of excess air leakage are often hard to detect. These openings might not be seen because of the internal finishes that have been fixed. 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 dwellings be tested, as there is a penalty for developments that are not tested.

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. 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. An air tight environment should be created in your building before the test to ensure optimal results. Do the following:

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

Building Envelope Measurement

We take the building envelope calculations before the test. The building envelope is the surface area of the structural barrier of a building. It separates the interior from the exterior part of the dwelling The calculations, which are extracted from the drawings, are fed into our estimations when testing your building for air leaks.

Envelope Area Air Permeability

Air permeability is measured as air leakage per hour per square metre of the building fabric at a pressure differential of 50 pascals (50n/m2). The air barrier envelope area is the total area of all the floors, walls and ceilings both above ground and underground. The internal dimensions of the building found in the drawings are used to calculate the envelope area and subtractions are not made from the areas of floors and ceilings with or without external walls or from the area of the junctions of internal walls.

Air Exchange Rate

Air exchange rate is vital to ventilation design but it isn’t used as the determinant of the actual design or calculation. The number of inhabitants and area of residence are used in measuring residential ventilation rates.

Measuring a Cold Roof Construction’s Envelope Area

Measuring if the roof area and ground floor area of a building are the same is vital. A cold roof has its insulation at the ceiling level, with space between the insulation and rafters.

Measuring a Warm Roof Construction’s Envelope Area

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 boundary or barrier containing the overall internal ‘conditioned space’ separating it from the external environment (or non-conditioned spaces and adjacent buildings), and this is located on the warm side of the insulation.

Building Preparation

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

How the Test Is Done

Examine the wind speed, barometric pressure and temperature. Fix a fan to an aperture, usually the door, in the building. Set up the testing gear. Note the air flow volume from the fan. This is the same as the air leakage from the building envelope. Increase the speed of the fan slowly till it gets to 55-60Pa. Record how the air pressure differs at each fan speed.

Calculating 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. Air Tightness Testing and Compliance

An airtight building has several positive impacts when combined with an appropriate ventilation system (whether natural, mechanical, or hybrid): Lower energy costs and need for heating appliances due to a higher level of heat retention. A functional ventilation system Your building will have less mould since moisture cannot escape into holes and cavities. Fewer draughts, causing more 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 Hoxton. We are cost effective and adhere to all building regulations.


Best Practice Procedures

The Building Regulations approved document Part L1A 2010 specifies that any new dwellings must be airtight. The regulation is focused on the conservation of fuel and power usage. The dwelling should be tested for air permeability in line with existing building standards, as stipulated by Approved Document Part L1A.

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

During air leakage tests, there are technical standards that must be used. This was mandated by ATTMA – Air Tightness Testing and Measurement Association–to align with building regulations and other rules. The technical standards ensure that all companies have similar testing procedures. They are:

  • “Thermal Performance of Buildings. Determination of air permeability of buildings. Fan pressurisation method” BS EN 13829:2001, and
  • “Thermal performance of buildings – Determination of permeability of buildings – Fan pressurization method” ISO 9972:2015
Call us today for a quote on 020 3372 4430
Or you can email us at info@af-acoustics.com

Part L 2010 Building Regulation Standards for England and Wales

Undergoing an air tightness test is compulsory for your new building, according to Part L of Building Regulations. Those exceptions only occur when there are two or more dwellings in a development. Three units of a dwelling type or 50% of all examples of that dwelling type should be tested. 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. An SAP assessor can decide which buildings can use the assumed value successfully. A testing procedure required by Building Regulations is expressed in ATTMA TSL1 for dwellings and ATTMA TSL2 for non-dwellings. Air leakage testing is compulsory for residential areas 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.

England and Wales: Building Regulations 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. Its basis is the National Occupation Standard (NOS) and Minimum Technical Competence (MTC) documents standard for testing and essentials for testing knowledge.

Air pressure testers have three levels

  • First Level – For buildings not more than 1m3-4000m3, typically single and smaller non-dwellings, a single fan is used to carry out air tightness testing.
  • 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.
  • Air tightness testing for phased, zonal handover, LCHR and multifaceted constructions is carried out by level three experts.

Air Tightness Test Report

Accredited testing companies issue air pressure reports. First, extraction fans are closed. Then, the details and results of the tests are written down in a report. The report adheres to the company’s methods and all standards and requirements of Building Regulations.

Air Tightness Test Results

AF Acoustics will make sure the result is written in line with test requirements, detect any part of the test that is not in line with the standards required and check actual air tightness against required rate. We will ensure the report correctly identifies the tester, customer, building and its address. 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

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

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

Here are the appliances you should seal temporarily;

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

Air Tightness Testing FAQ’s

Air leakage is the uncontrolled flow of air through gaps and cracks in the fabric of a building (sometimes called infiltration or draughts).

This is not to be confused with ventilation. Which is the controlled flow of air into and out of the building through purpose-built ventilators that are required for the comfort and safety of occupants.

Too much air leakage leads to unnecessary heat loss and discomfort to the occupants from cold draughts.

At AF Acoustics, we will endeavour to help you identify air leakage/infiltration paths.

There are a number of methods we employ to do this, including:

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

In the vast majority of cases the first two methods are sufficient to identify the most significant air leakage paths along with our expertise we will be able to point our the problem areas should they arise. The air leakage areas will have to permanently sealed and the test repeated to reduce the air permeability of the building. Where problems are larger and sealing cannot be addressed on the day, the building may need to be re-tested at a later date.

A test certificate from The Air Tightness Testing and Measurement Association (ATTMA)

A testing procedure is to be carried out to comply with TSL1 for domestic or TSL2 for commercial. The test certificate will include sufficient information to describe the building tested e.g. location, type and size (the envelope area is an important component in calculating the air permeability and must be accurate) plus the design air permeability as well as the actual result. A testing procedure should be representative of the actual building performance.

An indicative result is available at the time of testing. Certificates can be issued within a day of testing.

If required, you can request all calculations including pre, and post environmental measurements, individual static pressures, envelope area breakdown, flow readings and calibration certificates at no extra charge.

Air permeability is essentially a function of the pressure difference between the inside and outside of the building and the air flow rate through the fan(s), necessary to produce a pressure difference. This is averaged out over the envelope area. The result takes account of environmental conditions.

The final air permeability at 50 Pa is based on a logarithmic graph of pressure difference and flow rate, the graph should:

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

These are aspects that the building control should check carefully if choosing to accept air permeability results from non-accredited testing bodies.

Most air tightness tests for domestic units and simple commercial units are carried out in 45 – 60 minutes. This time may be extended if the test fails and leakage paths are investigated. We will normally charge for a retest depending on how much work is to be carried out.

On larger commercial units, which require 1 large air test fan, air tests take 1 hour if all temporary sealing has been completed prior to starting the air test.

If complicated or very large buildings are being air tested with multiple fan units, allow up to 4 hours for the test and longer if investigations are required.

The envelope area is calculated from the drawings and verified on site. The envelope of the building is all the surfaces that separate the heated interior from the unheated exterior of the dwelling. This includes walls, floors and the roof.

Generally, this involves mounting a door profile and incorporating one or more electrical fans into an external door opening(s). Depending on their orientation, the fans can be used to pressurise or depressurise the building. The resulting difference between the external and internal pressure can be used to calculate the permeability of the building envelope (given that the envelope area is known).

This permeability is an indicator of how air tight the building is, and whether there are openings in the envelope. Generally, 10 differential pressure points are taken at different fan flows to establish an accurate result for the building. Our certified specialised software is used to establish an accurate Air Tightness Test result.

Our experts at AF Acoustics will provide a simple checklist for building preparation, which includes the following:

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

All building preparations should be made before our test engineers arrive on the site this will ensure a smooth testing process and increase your dwelling’s chances of passing the test the first time. We will seal all the vents ourselves.

For multiple dwellings it may also be necessary to agree on the test programme with the building inspector before arriving on site.

Where possible, it is helpful to accurately calculate the envelope area and confirm the fan installation arrangements based on architectural drawings before coming to the site.

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

For dwellings, sufficient information is required to identify the different dwelling types and the number of each such as General Arrangement/Site Plan and Schedule (including other important details such as variation in storey height or construction method).

For buildings other than dwellings, the approximate envelope area is the key factor for quoting. It is required to establish the necessary fan arrangement. This affects the time on site and potentially the number of people, and this can be calculated from drawings – floor plans and elevations.

The testing body may also need to identify the potential aperture(s) into which test equipment is to be installed. In some circumstances this may require additional time on site, extra people or customised templates.

Approved Document L states that Building Control can accept evidence from BINDT or ATTMA Registered testers. However, the BINDT scheme was closed down at the end of 2014, subsequent to the last revision of Approved Document L. Additionally, The Independent Air Tightness Testing Scheme (iATS) is an authorised Competent Persons Scheme created for companies (including sole traders and partnerships) that carry out Air Tightness Testing.

The common leakage sites are:

All pipe works within the kitchen and bathrooms

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

Our team of experts can support you through the following

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

Additional AF Acoustics services – including noise survey, sound insulation testing services noise impact assessments

Employing the services of a reputable and accredited air tightness testing consultant, such as AF Acoustics, can help identify and remedy potential problem details in a building design prior to and during construction.

The Air Tightness Testing and Measurement Association (ATTMA) is approved by Department for Communities and Local Governments (DCLG) and is listed in the Building Regulations as an authorised Competent Persons Scheme for air tightness testing.

As an ATTMA registered company, AF Acoustics is independently certified by ATTMA with a scope covering air tightness testing to the ATTMA Technical Standards (TSL1 & TSL2) and BS EN: 13829 (2001), demonstrating knowledge and understanding, which enables us to test both commercial and domestic developments in accordance with relevant building regulations.

Part L sets the energy efficiency standards required by the Building Regulations. It controls:

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

It also sets out the requirements for SAP (Standard Assessment Procedure) Calculations and Carbon Emission Targets for dwellings. In addition to insulation requirements and limitations of openings of the building fabric.
Part L also considers:

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

Building Regulations are administered separately in England, Scotland and Wales.

The objective is to measure the volume of conditioned air escaping through the building envelope via uncontrolled ventilation at an induced pressure difference of 50 Pa. A simplified process is shown below:

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

No. However due to the penalties occurred to the air permeability value of non-tested properties, every property is usually tested. We can test all dwellings, including domestic buildings, industrial units, warehouses, schools, hospitals, residential care homes, hotels, offices, and retail units.

All new buildings and dwellings should be tested, but there are some exceptions and they are explained below:

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

No. Air tightness testing applies to:

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

Air tightness is an important factor in assessing the overall carbon emission of a building via the appropriate calculation methodology:

When a building is air tight, the amount of fuel needed to heat it is reduced. This conserves fuel and reduces the carbon dioxide produced, thereby lowering carbon emission and energy bills.

If you are building a new domestic property or commercial property of a certain size, it will need to undergo air tightness testing. This assesses the building for ‘air permeability’, checking for air leakage through gaps, holes and other areas. The Government has SAP (Standard Assessment Procedures) in place for air tightness testing, setting standards buildings must comply with to be energy efficient.

All residential properties and non-dwellings properties over a certain size (with a floor area greater than 500 m2) must undergo air tightness testing. With larger developments, a sample number of the buildings must be tested, depending on the size and construction of the properties. However, in practice all dwellings are likely to be tested, as non-testing attracts a severe penalty.

In a property where air tightness is below the recommended standard, the following problems can occur:

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

Load More

Image module

Gerard Finn

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