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

Air tightness testing, also called air leakage testing or air pressure testing, calculates the quantity of air escaping through openings in a building. 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.

Changes to building regulations have addressed air leaks which affect a building’s energy efficiency. Our certificates for air tightness testing are registered with the Air Tightness Testing and Measurement Association (ATTMA), a professional body that focuses on high quality air tightness testing and air permeability applications. As a certified air leakage testing company in Kenton, we are ready to provide testing services whenever you want. 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 an assessment on 020 3372 4430
Or you can email us at info@af-acoustics.com

What is Air Tightness Testing?

Air tightness testing involves calculating the quantity of air which escapes through holes in the building fabric. Other names for air tightness testing are air leakage testing and air pressure testing. Air leakage is the uncontrolled flow of air through gaps and cracks in the fabric (often referred to as infiltration or draughts) and not ventilation, which is the controlled flow of air in and out of the building. Draughts are uncontrolled ventilation. Using air tightness testing, the total air lost can be estimated. An excessive amount of uncontrolled air loss results in heat reduction, making the residents uncomfortable. As Government strives to reduce CO2 emissions from new buildings, building regulations now place greater emphasis on reducing air leakage from the building envelope. This reduces fuel consumption and CO2 emissions. 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. When the building fabric is properly constructed to reduce air loss, the building is economical, and energy efficient.

What Air Leakage Is

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. It leads to heat deprivation when cold draughts happen and warmth is needed the most. Because air leakage is uncontrolled ventilation, excessive air flows into the house during windy and wintry weather. 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.

The Impact of Air Leakage

Heat loss within a building can be caused by air leakage. 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 water vapour in the moist air condenses on the inner wall surface holes. After a while, it is absorbed into building materials and diffuses, causing potential structural problems. There could be a decrease in the toughness and solidity of wet wooden covering due to rot.

These problems will eventually cause structural harm to the building.
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. The potential of vulnerable wall structures to absorb condensed moisture is reduced when air barriers are properly installed and uncontrolled air flow is reduced. Proper ventilation, whether active or passive, is critical in expelling undesirable damp scents, water vapour and polluting substances.


Why Should We Do an Air Tightness test?

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. 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. Uncontrolled air leakage also results in health problems. Coupled with poor air circulation, it leads to the growth of mould and mildew. Best practice advice is to “Build tight, ventilate right”. Air leakage causes infiltration of moisture into the building envelope, leading to health issues and high repair costs.

When Is an Air Tightness Test Needed?

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. It’s not a necessity to perform tests on each property, rather, different kinds of houses are selected and tested. With selective testing there is a penalty of +2m3/h/m2; if the target score is 5 m3/h/m2 and selective testing was applied, the air tightness test would have to achieve a lower score of 3.

Where the dwelling has not been pressure tested, the assessed air permeability is the average test result obtained from other dwellings of the same dwelling type on the development, increased by +2.0 m3/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.

The reasons Why You Should Choose AF Acoustics for Your Air Tightness Testing

AF Acoustics air tightness testing professionalism has helped many homes and business owners in Kenton. Because of the following guarantees of working with us, we are highly endorsed by our clients.

Expert information and service

In Kenton, we have served many clients. The experience garnered from our years of service will help us meet your specific needs no matter the size or type 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. Our personnel will use their expertise to provide lasting solutions. Contact AF Acoustics in Kenton –the right team for your building.

We Are Registered Members of the Air Tightness Testing and Measurement Association (ATTMA)

We are registered members of the ATTMA, a professional association dedicated to promoting technical excellence in air tightness testing and air leakage measurement applications. This means our expertise and quality of services are recognised by the leading air tightness testing body in the UK.

When to Call Us to Test Your Building

We want you to be able to access comprehensive air tightness testing in Kenton whenever you need it. Pick a time that is convenient for you in our responsive scheduling options. We won’t make you wait or make the process complicated.

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

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 Fees

Save money by paying lower rates at AF Acoustics. As a business with low overheads, we’re able to give you one of the best air leakages testing services in Kenton at reduced costs.

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

Air Tightness Testing for Domestic & Commercial Buildings of All Types and Sizes in Kenton

Whatever the type and size of a domestic or commercial building in Kenton, AF Acoustics’ experts can test it for air permeability and issue an ATTMA certificate afterwards. Air tightness test checks the extent of uncontrolled air moving through openings in the building envelope. The results are registered as The test results are described as m3/h/m2 – (m3 per hour) per square metre of building.

Approved Document L1A and L2A demands that buildings take tests for air leaks. The maximum air permeability rate is 10m3/h/m2. The carbon discharge requirement for all buildings reduces the air permeability rate target. This target can be found in a building’s design-stage SAP assessment or SBEM. Excess air leakage causes heat loss, greater carbon dioxide discharge and can make occupants uncomfortable due to the influx of cold air. It also causes wind washing and thermal bypassing, resulting in lower energy performance. Infiltration/exfiltration is the effect of air pressure difference. Warm air rises while cold air falls. The warm air within a building rises and air pressure at the base falls; this results in air coming in through doors, windows and leakage points. 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 Kenton. Buildings where businesses are conducted will not cause discomfort to employees and clients because they have the legal air permeability rating. In addition, you get lower heating and cooling costs. A comfortable environment results in a higher productivity rate.

Part L Test Explained

Air tightness testing is a Building Regulations obligation for new buildings, commercial developments and revamped buildings. This was put into effect in 2006 after Document L was reappraised. Air tightness can also be called air leakage 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. The Building Regulations (Part L) demand that a selected group of different kinds of residential constructions and all non-domestic buildings greater than 500m2 perform air leakage tests. The highest air permeability target set is 10m3/h/m2 but your building might need a much lower one. Air leakage is vital to a building’s energy efficiency and is needed to meet Building Regulations Part L and carbon emission standards.

What Is Part F Test?

We can provide you all that you need to serve all your Part L and Part F requirements. 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.
Approved Document F of the Building Regulations requires that all mechanical extract fans in new dwellings be subjected to a flow rate test. Building Control Body (BCB) will see proof that the test has been conducted before signing off your building. Extractor fans can be tested and recorded, and test reports submitted using 3 methods. We use a vane anemometer, which is the third method called the minimum benchmark method, to conduct extract fan flow rate tests.


The types of Air Tightness Testing Services We Offer

Air Tightness Testing has different tiers, depending on how complex a building is and its size. Find them below: A single blower door fan is the instrument used for the first level to examine single buildings and smaller non-dwellings from 1m3 to 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. The third level tests big and complex zonal and phased buildings and complex high rise buildings.

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

Air leakage testing is the measurement of uncontrolled ventilation from a building’s fabric. The result is written as m3/h/m2 – (m3 per hour) per square metre of building envelope. Air pressure testing is compulsory, according to Approved Document L1A. Your building may need a lower rate to meet the CO2 discharge target. The required rate can be found in a building’s design-stage SAP assessment SBEM. An excessive amount of air leakage results in greater energy expenses, heat reduction and carbon dioxide emissions.

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

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 tightness testing is required by Building Regulations. The highest air permeability rate for your dwelling when tested should be 10m3/h/m2. The result of your dwelling’s air permeability rate might have to be lower than required due to SAP or SBEM assessment. The air permeability target can be found in a building’s design-stage SAP or SBEM assessment. Too much air leakage leads to heat loss (and consequently, higher CO2 emissions) and draught.

We Test Your Automatic Opening Vent’s Smoke Shaft

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. An air tight shaft creates sufficient pressure difference and ensures that the fans and vents perform properly to draw out smoke from a dwelling and save its occupants. To ensure that automatic opening ventilations work properly, their manufacturers have placed an air permeability target for them which we work towards. An air pressure test is conducted using a fan installed in the shaft. The openings for ventilation grilles and extract points on each floor are closed so that the state of the shaft itself is known. The fixing and commissioning of the auto opening vents happen after the test is completed.

Testing Extraction Fans for Air Flow

The mandate to construct well insulated and air tight buildings, has made it crucial for satisfactory, enhanced and balanced ventilation systems to be installed. We are able to test extraction rates. This is done to meet the Building Regulations standard. Make sure the ventilation system is efficient, expels pollutants and odours, and reduces humidity, especially in kitchens and bathrooms. 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.

Specific Test and Building Preparation Procedure

The measurement of air pressure in a building is known as 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.

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 best solution to demonstrate a building’s air tightness level is to check for leakage paths in the building envelope.

With residential buildings in an area, new building regulations demand that a minimum of 20% be measured for air leakage. Consistent samples are determined by the quantity of the different types of houses present during the construction of the project. We recommend that all buildings be tested as those that aren’t are penalised.

What You Need to Do Before Undertaking the Test

The client needs to send our test engineers the drawings of the development (plans and elevations) and target air permeability requirements. An Air tightness test can be done in 30 – 60mins. Wind speed should not exceed 6m/s. Test engineers need to know the size of a building envelope and requirements before coming to the site. To get the site ready, make the place air tight by closing and securing all external doors, windows, ventilation and smoke vents. Remember to turn off range cookers or stoves a day before testing as well as mechanical ventilation systems, and fill all drainage traps.

  • Open and secure all internal doors;
  • Close all windows;
  • Switch off all mechanical ventilation systems;
  • Seal ventilation;
  • Close smoke vents;
  • Fill all drainage traps;
  • Switch off all range cookers/stoves 24 hours before testing (if applicable)

Calculating the Building Envelope

We take the building envelope calculations before the test. A building envelope is the boundary between the conditioned and unconditioned environment of a building. The measurement is obtained from the construction drawings, and put in our calculations to conduct the test.

Air Permeability from the 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 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. The number of inhabitants and area of residence are used in measuring residential ventilation rates.

Calculating the Envelope Area of a Cold Roof

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

In a warm roof, the main insulation is placed below the roof covering. The envelope area is the boundary between the internal environment and external environment (adjacent buildings), and can be found on the insulation’s warm part.

Preparing the Building

  • Shut all windows
  • Close the smoke vents
  • Shut and secure all inner doors
  • turn off the mechanical vents
  • Temporarily seal vents
  • Fill and block drainage traps

Site Test Procedure

Evaluate the weather (barometric pressure, wind speed and temperature) Connect a fan to an aperture within the construction envelope. For example, the door. Set up the equipment for air tightness testing. Note the air flow volume from the fan. This is the same as the air leakage from the building envelope. Gradually increase the fan speed from 20-25 Pa to a maximum of 55-60Pa. Record pressure differences across the building at each fan speed.

Calculating Air Leakage

Our air leakage measurement involves picking out the gaps where air leakage takes place, recording the test information, sending results to customers in a technical report and advise clients on repair methods in the case of a test failure. Testing for Air Permeability and Following Part L Building Regulations

When a building has the right kind of ventilation (mechanical, natural or a combination of both) and has a low permeability rate, the advantages to the occupants are numerous. Some of them are: Lower energy costs and need for heating appliances due to a higher level of heat retention. Better performing ventilation system Less mould will be trapped in the building fabric as a result of less moisture. Fewer draughts, causing more comfort From the smallest to biggest building or development, we adhere to Building Regulations Part L and Building Standards. Our services include: air pressure testing, support services, re-examining designs and consultancy for all buildings in Kenton. We are cost effective and adhere to all building regulations.


Good and Best Practice Styles

Building Regulation Part L1A 2010 stipulates that all new buildings must have low air permeability. The regulation helps to reduce the use of fuel and power. The dwelling should be tested for air permeability in line with existing building standards, as stipulated by Approved Document Part L1A.

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). 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 an assessment on 020 3372 4430
Or you can email us at info@af-acoustics.com

England and Wales: Building Regulation Targets Part L 2010

Approved document L1A has made it compulsory for all new buildings to be tested for air leaks. Where there are two or more new buildings in an area, conduct a test on 50% of all examples of a kind of dwelling or 3 units of a dwelling kind. Where there are only one or two new buildings, add an assumed value of 15m3/h/m2 to the DET/TER measurements; an air tightness test may not need to be carried out. To find if your building falls into this category, contact your SAP assessor. There are different ways that Dwellings and Non-Dwellings should be tested. ATTMA TSL1 and ATTMA TSL2 have clearly stated these. 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.

Building Regulation Requirements Part L (England and Wales)

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. It mirrors the operation standards and skill requirements set by the National Occupation Standard (NOS) and the Minimum Technical Competence (MTC) document.

Air tightness testers can be divided into three categories

  • 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.
  • Second Level – Testing is done in buildings with 4000m3 and higher. Large high rise and phased handover buildings are excluded from the test except a level three tester is in charge.
  • 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.

Air Tightness Test Report

Air leakage test reports are given by authorised organisations that test different buildings. Sealed extraction fans are sealed for testing and the details and results of the test are written in a report afterwards. The organisation makes sure the report meets the company and government’s requirements.

Test Outcomes

AF Acoustics will ensure the test result is written in accordance with the test standard requirements, identify any deviations from the relevant standards within the report and check air tightness against target value. Clients’ test reports contain their names, construction, address; the tester’s name is also included. 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

Please send your design air pressure figure to us and go through the list below before we arrive at your site.

Air Leakage Pathway Listing – You must ensure the following are properly sealed and don’t have any openings.

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

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.

Working Hours

  • Monday 08:00 - 18:00
  • Tuesday 08:00 - 18:00
  • Wednesday 08:00 - 18:00
  • Thursday 08:00 - 18:00
  • Friday 08:00 - 18:00
  • Saturday Closed
  • Sunday Closed