Longford Air Tightness Testing, Licensed by AF-Acoustics

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

Air leakage occurs through any opening in the building envelope and can affect a building’s energy performance, this has been addressed by changes to the building regulations. 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. We are dedicated and accredited air leakage testing service providers in Longford and we are available to provide you with testing services whenever required. You can also call or email us for any of these services:

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

As registered members of the Air Tightness Testing and Measurement Association, our air leakage test certificate is accepted as evidence for Building Regulations sign-off. If you want specialist air pressure testing services in Longford, AF Acoustics’ tightness testing services will

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

Our services provide great value for money at high standards.

Our Guarantee

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

Air Tightness Testing – What It Means

Air tightness testing is a 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, also known as infiltration or draught, allows air to pass through unwanted leaks in a building; unlike ventilation where the air inside and outside of a building and its flow from one end to the other is controlled. Air tightness testing is the recognised method used to measure total air lost through leaks in a building fabric. This is often referred to as uncontrolled ventilation (draughts). When too much air leaks through a building’s fabric, heat loss occurs, making the occupants 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. Air tightness testing is a crucial activity that

  • shows the air leaking from gaps in a 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. This can make a building more energy efficient since air leakage is under control. It will also be cost effective and of high quality.

What Air Leakage Is

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. Because of the nature of air leakage, excessive air infiltration might occur in a building when the weather is windy and chilly. This results in loss of warmth and an unpleasant cold draughts. Air leakage and a dwelling’s energy efficiency are intertwined. Testing is needed to verify that air tightness levels used in the building’s energy calculations align with the targets required by the law. In England and Wales, air tightness testing has been obligatory since 2006. All new dwellings and non-dwellings over 500m² are to be tested for air permeability.

The Impact of Air Leakage

Heat loss within a building can be caused by air leakage. Once the atmosphere is cold and windy, unwanted chilly air infiltrates the building through gaps, leading to heat reduction. 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 air hits the cooler surface in the inner parts of the wall. Water vapour condenses and gathers in these gaps. Eventually, it is absorbed and starts a myriad of defects. Wet wooden overlay or framing can decay, decreasing its durability.

These problems will eventually cause structural harm to the building.
Other damages that can occur are cold homes which make occupants uncomforta-ble, increase in heating bills to make the internal temperature warmer, and more carbon dioxide discharge since additional heat is required.

Successfully managing the movement of air into and outside the building will limit the damaging effects of moisture. The potential of vulnerable wall structures to absorb condensed moisture is reduced when air barriers are properly installed and uncontrolled air flow is reduced. Passive or active ventilation is required to reduce water vapour, moisture odour and pollutants.


Why You Should Conduct an Air Tightness Test

Air tightness is an integral element of energy efficiency. It is part of government’s plan to overcome climate change through advancements in the energy performance of buildings. Heating buildings contribute to global warming and CO2 emissions, since fossil fuels are used to create heat. Reducing air leakage reduces heat loss, which in turn reduces the amount of energy a heating system uses. 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”. The result of uncontrollable air moving into the building fabric could be health problems and costly repairs.

Recommended Period for Air Tightness Test

Best practice says that air tightness tests should be carried out early in construction and after the final phase. The results of the test can affect a building’s energy ratings because they play a part in SBEM and SAP calculations. It’s not a necessity to perform tests on each property, rather, different kinds of houses are selected and tested. 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.

The assessed air permeability of an untested residence is a calculation of the average test score of the same kind of dwelling in the development, increased by 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

At AF Acoustics, our air tightness testing expertise has helped many home and business owners in Longford. Our clients highly recommend us for the following reasons.

Great service and expertise

In Longford, 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. If you need knowledgeable and trustworthy air leakage experts who can provide exemplary results, AF Acoustics is the team you need in Longford.

We Are Registered Members of the Air Tightness Testing and 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.

Picking a Time for Your Air Permeability Test

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

Next-day Turnaround for Certificates

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

Competitive Charges

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 Longford at reduced costs.

Call us today for a quote 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 Longford

All domestic and commercial buildings in Longford can be tested by AF Acoustics, no matter how complex they are. The air tightness tests are carried out by competent testers and you will be issued an ATTMA certificate. An air leakage test is used to determine the level of uncontrolled air flow through gaps or cracks in the fabric of a building. The result is expressed as a quantity in the form of The test results are described as m3/h/m2 – (m3 per hour) per square metre. of building fabric.

Approved Document L1A and L2A requires that buildings know their air permeability rates by taking the air leakage test. Each building tested must achieve a maximum air permeability rate of 10m3/h/m2. In order to comply with the carbon emission target, 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 assessment or SBEM for that building. Several problems are caused by uncontrolled ventilation. They are:

  • Infiltration of cold air
  • Wind washing and thermal bypassing, which is when air moves through the inner building of a building fabric to create convective loops inside the walls, making the building less energy efficient
  • Reduction in heat and CO2 emission.

Infiltration/exfiltration is the effect of air pressure difference. Warm air rises while cold air falls. The warm air within a building rises and air pressure at the base falls; this results in air coming in through doors, windows and leakage points. Air permeability testing is a legal requirement for constructions in Longford. This way, they can have high energy performance, meet building regulations requirements and get signed off by building control. Clients and employees will be at ease in their surroundings. Heating and cooling expenses are also reduced and the environment is more productive.

A Description of Part L Test

Air tightness testing has been a mandatory part of the Building Regulations for new build and refurbishment projects since Approved Document L was revised in 2006. Air tightness can also be called air leakage or air permeability rate. Air leakage can occur through gaps, holes and cracks in the fabric of the building envelope (service penetrations, wall/roof junctions, etc), which are not always visible. 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.

The Part F Test

We can provide you all that you need to serve all your Part L and Part F requirements. We deliver quality air permeability and extract fan flow rate testing, and also recommend skilled experts who will handle your water calculations, SAP calculations and Energy Performance Certificates.
According to Part F, it is compulsory for a flow rate test to be conducted on all mechanical extract fans of new buildings. Your building won’t be signed off until Building Control Body (BCB) has been presented the results of the test. There are three alternative methods which can be followed to test, record and report the testing of extractor fans. Use method 3 – the minimum benchmark method, which tests extractor fans with vane anemometers. This is our testing procedure.


What Kinds of Air Tightness Testing Services Do We Offer?

Here are the descriptions of the ways air permeability can be tested: A single blower door fan is used for air tightness testing for single buildings and smaller non-dwellings not more than 4000m3. Level 2: Air pressure testing for simple and complex buildings larger than 4000 m³ gross envelope volume which does not include large and complex, high rise (LCHR) buildings, and phased handover/zonal buildings. Air tightness testing for phased, zonal handover and LCHR constructions is done.

Domestic Buildings Testing as Required by Approved Document L1

Air pressure testing, involves the calculation of air escaping through openings in a building. The result of the air leakage test is expressed as a quantity of air leakage (mm3 per hour) per square metre of building envelope. Document L1A of Building Regulations declares air leakage testing to be mandatory. A lower air permeability rate might be needed due to carbon emission requirements. You can find the required air permeability rate of your building in its design-stage SAP assessment SBEM. Uncontrolled ventilation can cause several problems. They are: infiltration of cold air, reduction in heat, more CO2 emission and higher energy costs.

Commercial Building Testing as Required by Approved Document L2A

Air tightness testing determines the extent of air leaking from a building’s envelope. The air leakage test result is written as m3/h/m2 – (m3 per hour) per square metre of building. Document L2A of Building Regulations declares air leakage testing to be mandatory. The highest air permeability rate for your dwelling when tested should be 10m3/h/m2. In order to comply with the SAP assessment, it may be necessary to achieve a lower air permeability rate. To get your building’s required air permeability rate, check its design-stage SAP or SBEM assessment. An excessive amount of air leakage leads to greater energy expenses, heat reduction, carbon dioxide discharge and draughts.

We Offer Smoke Shaft Air Pressure Testing

Smoke shaft needs to be tested because its air tightness determines the performance of the automatic opening vent fitted on it. Our professionals perform the test. When there is a fire, the auto opening vents play an important part in expelling smoke in multi-storey buildings. 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. With the right air permeability rate, the vents can operate at their best. We aim for the air permeability rate set by the vent manufacturers. An air pressure test is taken for the smoke shaft by installing a fan inside. The usual openings are closed off too so that the shaft’s integrity can be determined. This test is conducted before the automatic opening ventilation is fixed and commissioned.

Measurement of Air Flow of Domestic Ventilation

The requirement for air tight buildings that are properly insulated has brought about the need for ventilation systems that are adequately installed and function at an optimal level. We are able to test extraction rates. This test is required by law and it enables a building have a high-quality ventilation system that is efficient and removes pollutants and odours while limiting humidity in rooms, especially in kitchens and bathrooms. Building Regulations Part F also requires that the air flow test of all extractor fans (such as kitchen and bathroom extract fans) in new buildings to be conducted and results given to Building Control before construction ends.

Precise Air Pressure Test and Building Procedure

The measurement of air pressure in a building is known as an air tightness test. If the rate of air pressure is good, the energy performance of a building will be high and the inhabitants will be comfortable.

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. If you know the leakage paths of a building, you will know if it is air tight.

Under the new regulations developers must test 20% of the dwellings on a site but this also depends on the amount of differing house types to ensure that a consistent sample is taken throughout the construction of the development. There is a penalty for untested constructions. Therefore, we suggest air leakage tests for all buildings.

Pre-Test

Clients should send the drawings (plans and elevations) and air permeability requirements to our engineers. 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. An air tight environment should be created in your building before the test to ensure optimal results. Do the following:

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

Calculating the Building Envelope

Before coming to the site, we get the measurement of the building’s envelope. The building envelope is the surface area of the thermal boundary of the building. The building envelope calculations are taken from the drawings and used for our air tightness testing.

Air Permeability of the Envelope Area

Air permeability, according to Approved Document L1A (2010), has to do with “air leakage rate per hour per square metre of envelope area at the test reference pressure differential of 50 pascals (50n/m2)”. The building’s envelope area has to do with the total area of all the floors, walls, and ceilings bordering the internal environment, including those below external ground level. These include shared walls, floors and ceilings in storey buildings. Internal dimensions are used to measure the envelope area.

Air Changes Per Hour

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. To calculate ventilation rates for domestic buildings, the area and number of people living in the building are considered.

Cold Roof Construction Envelope Area Calculation

Measuring if the roof area and ground floor area of a building are the same is vital. A cold roof has the insulation at the horizontal ceiling level and a large void or space between the insulation and the pitched roof rafters.

Warm Roof Envelope Area Measurement

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

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

Process for Testing the building

Check all weather conditions such as temperature, wind speed and barometric pressure. Connect a fan (or fans) to an aperture in the building envelope (e.g. 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. Raise the fan speed from 20-25Pa to the highest speed of 55-60Pa. Record pressure differences across the building at each fan speed.

Air Leakage Measurement

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. Air Tightness Testing and Compliance

A low leakage building that is properly ventilated, whether natural, hybrid or mechanical, is very beneficial. The benefits are: Reduced heating expenses because of lower heat loss, with less need for equipment that has high heating ability. A functional ventilation system Your building will have less mould since moisture cannot escape into holes and cavities. Infiltration of air is reduced and the inhabitants are more comfortable. Our clients can expect a stress-free conformity to Part L Building Regulations standards, whether they have a single building or a large commercial building. 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 Standards

All new buildings, residential or commercial, must be air tight, according to Approved Document Part L1A of Building Regulations (2010). Reduced power usage and fuel conservation are important; that’s why the rule was put in place. Part L1A has demanded that all new dwellings be tested for air leaks in line with other regulations.

Testing for Air Permeability on Building Fabrics, According to L1 Technical Standard.

ATTMA has specified technical standards that must be adhered to while testing buildings in the UK, according to 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

Part L 2010 Building Regulation Standards for England and Wales

Test for air permeability must be conducted on your new constructions. This is stated in Approved Document L1A. For development with two or more buildings, three units of each dwelling type or 50% of the dwelling type should be tested. 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. To find if your building falls into this category, contact your SAP assessor. The required process for testing buildings for air tightness has been declared in ATTMA TSL1 for occupied buildings and ATTMA TSL2 for unoccupied ones. Air leakage testing is required on all residential developments (this may be a sample of units) and certain Non-Dwellings. Non-dwellings where floor area is less than 500 m2 or has an assumed assessed air permeability rate of 15 m3/h/m2 in their calculations, may not have to undergo the air leakage test.

Building Regulation Requirements Part L (England and Wales)

An industry-wide competence scheme endorsed by the government is carried out by the ATTMA. It was launched in January 2015 as stipulated in the 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 leakage testers have three levels

  • Level 1: Testers can test dwellings and non-dwellings up to 4000m3 gross envelope volume when tested as a single entity, with a single fan.
  • 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 3: These are air tightness experts who can cover large, complex and or high-rise buildings and or phased handover or zonal compartmentalisation.

Report for Air Leaks Test

Test reports are issued by registered and licensed air tightness companies who test buildings of different sizes and complexities. Extraction fans will be sealed temporarily; the results of the test are recorded in a short report. This is done according to the testing organisation’s procedures and Building Regulation standards.

Test Results

AF Acoustics guarantees the test outcome is written in line with standard requirements; it picks out any deviations from the significant benchmarks inside the report and checks air permeability against target values. Clients’ test reports contain their names, construction, address; the tester’s name is also included. Where it’s needed, we will identify if your building passed or failed the test and suggest ways to repair the building envelope before a retest is done.

Resources Air Tightness Checklist – Building

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

Air Permeability Pathway List – We will inspect every part for the building envelope for leaks.

  • Windows: Examine the seal below the sills and around the frames.
  • Doors: Inspect the seal around all external door surrounds. This is more applicable to French doors.
  • Drainage traps: Make sure they’re not filled with water.
  • Skirting and coving: Examine every part and seal where needed.
  • Meter Boxes: Make sure the external supplies are properly covered.
  • Light Fittings: Inspect the seal around all light fittings and switches.
  • Radiators/Fans /Heaters: Check the seal on pipes and wires.
  • Boilers: Inspect the seal around the boiler supply and flue.
  • Extractor Fans: Inspect the edge of the extracts and seal the front of the grill.
  • Cooker Hoods: Examine the seals around all penetrations.
  • Soil pipes: Inspect the seal around all soil pipes and sink waste pipes especially those inside or behind kitchen cupboards.
  • Bath Panels: Make sure all the pipes behind bath panels are sealed properly.
  • Hot water tank: Examine the seal around supply pipes.
  • MVHR: Examine seal around all terminals.
  • Chimneys: Cover the open fireplaces.
  • Junction between floor and wall under kitchens and baths
  • Tumble drier extracts: Study the seal around the extract.

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.