Air Tightness Testing, Certified by AF-Acoustics, in Fairlop

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 became an integral part of building regulations for new buildings, commercial developments and revamped buildings in 2006 after Document L was reviewed.

Changes to building regulations have addressed air leaks which affect a building’s energy efficiency. We register our air tightness certificates with the Air Tightness Testing and Measurement Association (ATTMA), an organisation that encourages proper air leakage applications and promotes quality air tightness screening. AF Acoustics, a licensed air tightness testing company, is available to provide testing services at your request. Our address is Fairlop. You can also call or email us for any of these services:

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

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. AF Acoustics provides services that are cost effective and of high standard.

Our Guarantee

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

Air Tightness Testing Explained

Air tightness testing is a method of measuring the extent to which air is lost through leaks in the building fabric. Air tightness testing is also known as air pressure testing or air leakage testing. Air leakage should not be confused with ventilation. Also called draughts or infiltration, air leakage is unrestrained movement of air through holes in a building fabric, while ventilation is the restrained and planned movement of air. Draughts are uncontrolled ventilation. Using air tightness testing, the total air lost can be estimated. Too much air leakage leads to unnecessary heat loss and discomfort for the occupants. 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. 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. Building plans will often consider air tightness at the beginning stages of development so as to measure up to stricter building standards. This can make a building more energy efficient since air leakage is under control. It will also be cost effective and of high quality.

Air Leakage Explained

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 called infiltration, it differs from ventilation which is the regular, planned and restrained flow of air into a building. It may cause uncontrolled influx of air during frosty and windy weather. This reduces the temperature of the building, making the occupants uncomfortable. Testing for air leakage plays a primary role in determining the energy efficiency of a building. It is an important procedure that measures the air tightness level to ensure that the regulatory standards have been attained and the building’s energy calculations have been properly accomplished. In England and Wales, air tightness testing has been mandatory since 2006 for all new builds and non-dwellings with a floor area over 500m².

Air Leakage’s Resulting Outcomes

Air leakage leads to heat reduction. When the weather is cold and windy, unwanted air seeps into a building through the holes and cracks in its fabric, causing heat loss and discomfort. 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. Wet wooden framing or sheathing can rot and break down, diminishing its strength.

The building becomes structurally damaged as time goes on.
The inhabitants become uncomfortable because of chilly homes, heating expenses increase and more CO2 is emitted due to the additional heat 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. The potential of vulnerable wall structures to absorb condensed moisture is reduced when air barriers are properly installed and uncontrolled air flow is reduced. Correct ventilation, whether passive or active, ensures fresh air circulates through the building, eliminating water vapour, moist odour and polluting substances.


Why is an Air Tightness Test Important?

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 involves burning fossil fuel which increases CO2 emissions and causes global warming. The best way to reduce the quantity of fossil fuel burnt is by stopping air leakage which reduces heat loss. Properties with uncontrolled air leakage also cause health issues. A building with poor ventilation and high air permeability is conducive for moisture and mould growth which can affect the inhabitant’s health. To “Construct tight, ventilate right” is the best practice. High levels of air leakage can lead to moisture ingress into the building fabric, resulting in expensive repair costs and potential health problems due to mould.

When Is an Air Tightness Test Needed?

A building should ideally be air tightness tested early in the construction process and again at the end of the building project, although sometimes only the final check is carried out. The test results are used in SAP and SBEM calculations, this impacts the energy rating of new building. Individual property is not tested in a large residential development. The test is done on different types of houses within the area. 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. This type of testing does not reveal the exact air tightness of each residence and is therefore not advisable. Moreover, the penalty implemented on untested buildings makes the required air permeability rate difficult to attain.

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 Fairlop. Our customers highly recommend us to other people due to the following benefits.

Expert information and service

Our vast experience in serving a variety of clients in Fairlop guarantees we have the expertise to satisfy your needs regardless your unique circumstances, type or size of property. Our accredited air testing experts are polite and competent. They are trained to provide the service you need and fit around your project. If you need knowledgeable and trustworthy air leakage experts who can provide exemplary results, AF Acoustics is the team you need in Fairlop.

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.

Picking a Time for Your Air Permeability Test

You can access our complete air tightness test in Fairlop at anytime. Pick a time that is convenient for you in our responsive scheduling options. You won’t get delays or difficulties when scheduling.

Next-day Turnaround on Test Certificate Where Possible

In order to satisfy our clients, AF Acoustics strives to provide test results and certificates on the next day.

Fair Pricing

AF Acoustics offers competitive fees in Fairlop. 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

Air Tightness Tests for Any Kind of building in Fairlop

Whatever the type and size of a domestic or commercial building in Fairlop, AF Acoustics’ experts can test it for air permeability and issue an ATTMA certificate afterwards. 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 results are written as 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. With air leakage comes heat loss, greater CO2 discharge, draughts, thermal bypassing and wind washing and poor energy performance. Exfiltration/infiltration of air is caused by the difference in air pressure inside and outside the building. Lower pressure occurs as warm air rises and brings air inside through any available opening. Air tightness testing is required by law for domestic buildings to ensure energy efficiency and comfort within the home environment. It is also a legal requirement that all new builds have an air tightness test carried out to meet energy efficiency standards before it can get signed off by building control in Fairlop. With air leakage tests, business areas are more comfortable for employees and customers. 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. The air-tightness of a building is known as its ‘air permeability’ or leakage rate. Air leakage can happen via holes and splits in the texture of the building envelope (divider/rooftop sections, service penetrations, etc), which may not be obvious. Part L of the Building Regulations requires that all non-domestic buildings which have a gross floor area greater than 500m2, be subject to mandatory air permeability tests. For domestic dwellings, a sample of houses (in a development) must be tested. The maximum air permeability rating allowed is 10m3/h/m2, but your building might need a lower rating ts. Air permeability is key in the following areas: i. A construction’s energy performance, ii. CO2 emission targets iii. Building Regulations Part L standards

The Part F Test

We can provide you all that you need to serve all your Part L and Part F requirements. With our organisation, you receive:

  • Expert fan flow rate testing
  • Experienced air pressure testing
  • Professionals who provide Energy Performance Certificate, water and SAP calculations.

According to Part F, it is compulsory for a flow rate test to be conducted on all mechanical extract fans of new buildings. Your building won’t be signed off until Building Control Body (BCB) has been presented the results of the test. Examining, documenting and submitting reports of extract fans’ test can be done using three methods. Using a vane anemometer, our testing procedure follows Method 3 – The minimum benchmark method.


The types of Air Tightness Testing Services We Offer

There are different levels of air tightness testing established from the size and complexity of a building. An overview of each is provided below: A single blower door fan is used for air tightness testing for single buildings and smaller non-dwellings not more than 4000m3. Second Level – Testing is done for building 4000m3 and higher, typically simple and complex dwellings. High rise and phased handover buildings are not part of this test. The third level tests big and complex zonal and phased buildings and complex high rise buildings.

Domestic Buildings Testing as Required by Approved Document L1

The measurement of air emitted by a building is tested to determine air permeability rating. 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. In order to comply with the carbon emission target, it is necessary to achieve a lower air permeability rate. The design-stage SAP assessment SBEM of a construction records its required air permeability rate. An excessive amount of air leakage results in greater energy expenses, heat reduction and carbon dioxide emissions.

Commercial Building Testing as Required by Approved Document L2A

Air leakage testing is the measurement of uncontrolled ventilation from a building’s fabric. The result of the air leakage test is expressed as a quantity of air leakage (m3 per hour) per square metre of building envelope. Air pressure testing is compulsory, according to Approved Document L2A. The results of air permeability rate should not exceed 10m3/h/m2. In order to comply with the SAP assessment, it may be necessary to achieve a lower air permeability rate. The design-stage SAP or SBEM assessment of a construction records its required air permeability rate. An excessive amount of air leakage leads to greater energy expenses, heat reduction, carbon dioxide discharge and draughts.

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. 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. To ensure that automatic opening ventilations work properly, their manufacturers have placed an air permeability target for them which we work towards. Fans are placed in the smoke shaft to conduct an air tightness test. The usual openings are closed off too so that the shaft’s integrity can be determined. The test takes place in advance of the automatic-opening ventilation equipment being installed and commissioned.

Air Flow Measurement of Domestic Ventilation (extraction fan testing)

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 evaluate extraction rates. This has not only been made compulsory by Building Regulations; it also helps reduce humidity in rooms, bathrooms and kitchens and expel pollutants. 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. The air tightness of a building improves its energy efficiency and internal environment.

It is difficult to notice unwanted openings in a building envelope. They might be blocked by the internal finishes. The best solution to demonstrate a building’s air tightness level is to check for leakage paths in the building envelope.

Under the new policies of building developments, the lowest number of domestic buildings developers have to test in an area is 20%. However, this depends on the quantity of different house kinds to ensure there is a regular sample throughout the survey. We recommend that all buildings be tested as those that aren’t are penalised.

What You Need to Do Before Undertaking the Test

Send the drawings of your dwelling (plans and elevations) and its target air permeability requirements to our test engineers. 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:

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

Calculating the Building Envelope

Before coming to the site, we get the measurement of the building’s envelope. The building envelope is the physical separator between the indoors and outdoors. The calculations are taken from the drawings. These are then incorporated into our calculations when we air test the property.

Air Barrier Envelope Area

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 Changes Per Hour

Air exchange rate is vital to ventilation design but it isn’t used as the determinant of the actual design or calculation. Residential ventilation rates are calculated based on area of the residence and number of occupants.

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.

Calculating the Envelope Area of a Warm Roof

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.

Getting the Building Ready

  • Temporarily seal and switch off all ventilation grids, smoke vents and mechanical ventilation systems
  • Close the windows and internal doors
  • Seal drainage traps.

Building Test Method

Check weather conditions (wind speed, temperature, barometric pressure); Place the fan on an aperture within the building envelope. Set up the testing gear. Using the fan, measure the air flow volume, from the building fabric. Gradually increase the speed of the fan to a maximum of 55-60Pa. Record how the air pressure differs at each fan speed.

Measuring air leakage

Our competent engineers note the points of air leakage, examine the test data and send test results to the customer in a technical report. If the test fails, we inform clients on what to do about it. 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: The occupants will pay less for heat because less heat is lost and they won’t need equipment with high heating capacities. Better ventilation system Reduced chance of mould and rot, as moisture is less likely to become trapped Fewer draughts and enhanced comfort Our air leakage tests are conducted according to building regulations and targets, whether we’re testing a small dwelling or big commercial development. They also ensure that you spend less money. Here are the services we provide:

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

Good and Best Practice Styles

The Building Regulations approved document Part L1A 2010 specifies that any new dwellings must be airtight. The regulation helps to reduce the use of fuel and power. Part L1A states that any new building must undergo an air pressure test, according to present regulations.

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

Certain technical standards are to be employed during air pressure test in the UK, as specified by ATTMA, building regulations and other documents. They explain in detail and provide guidelines for 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”.

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

Building Regulation Requirements Part L 2010 (England and Wales)

Approved document L1A has made it compulsory for all new buildings to be tested for air leaks. 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. If there are no more than two new dwellings, using an assumed value of 15m3/h/m2 in the DET/TER calculations might exempt them from air tightness testing. Your SAP assessor will be able to confirm if this is the case for your dwelling. 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. 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.

Building Regulations for England and Wales, Part L

Most competent air pressure testing companies go through the ATTMA scheme, which began in January 2015, etence. The scheme is endorsed by the government and recognised by approved documents L1 and L2 of building regulations. Minimum Technical Competence (MTC) and National Occupation Standard (NOS) documents are the basis for the scheme.

Air leakage testers have three levels

  • First Level – For buildings not more than 1m3-4000m3, typically single and smaller non-dwellings, a single fan is used to carry out air tightness testing.
  • Air tightness testing is done in all dwellings but big phased handover/zonal and high rise (LCHR) constructions are not included except a level three tester is the head of the team.
  • Level Three: Testing for the air pressure of high rise (LCHR) buildings, phased handover/zonal buildings and other complex buildings is carried out by level three experts.

Report for Air Leaks Test

Air tightness reports are issued by accredited firms that carry out air permeability tests on buildings of different sizes or complexities. First, extraction fans are closed. Then, the details and results of the tests are written down in a report. The organisation makes sure the report meets the company and government’s requirements.

Test Results

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. If a building fails the test, we provide remedial suggestions before a retest is carried out.

Resources Air Tightness Checklist – Building

Go through the list below and send the design air testing permeability value to us before we get to the site.

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

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.