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

Air tightness testing, otherwise called air pressure testing or air leakage testing, is the measurement of the outflow of air from a building’s fabric. In 2006, Approved Document L was reviewed and building regulations for air permeability became more stringent. The test is presently a requirement for new buildings and reconstructions.

Air leakage occurs through any opening in the building envelope and can affect a building’s energy performance, this has been addressed by changes to the building regulations. AF Acoustics certificates are certified by Air Tightness Testing and Measurement Association (ATTMA). ATTMA is an association of specialists that concentrate on promoting the best air tightness measurements and air permeability testing techniques. We are dedicated and accredited air leakage testing service providers in Teddington and we are available to provide you with testing services whenever required. You can also contact us for assessments and consultancy services. In addition to air leakage testing, we provide 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 provide air leakage testing in a professional manner by explaining the testing procedures and highlighting leakage areas in the building fabric. We also suggest long-term remedies based on the results of the tests. We deliver professional value for money service to the highest 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 Explained

Air tightness testing is a technique whereby a newly constructed building is evaluated and the quantity of air leaking through is measured. Air tightness testing is also known as air pressure testing or air leakage testing. Air leakage 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. Air tightness testing is done to calculate the total quantity of air that escapes through cracks in the building. Such air leakage is called uncontrolled ventilation (draughts). An excessive amount of uncontrolled air loss results in heat reduction, making the residents 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.

The introduction of tougher regulations has led to the construction of high-quality buildings. Building designs employ air tightness procedures from the early part of construction, creating a building that has adequate air tightness built into its design. Incorporating this at the beginning of the construction process makes the development more cost effective and energy efficient.

What Is Air Leakage?

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. How do you know if a building is energy efficient? By testing its air permeability. This lets the occupants know if the building meets standard air-tightness requirements. In England and Wales, air tightness testing has been obligatory since 2006. All new dwellings and non-dwellings over 500m² are to be tested for air permeability.

Effects of Air Leakage

Air leakage leads to a reduction in heat. During windy weather, cold air infiltrates a building through the openings in its fabric. This results in heat loss. It doesn’t stop there. Warm, damp air within the building escapes the gaps in its envelope. When moist air hits a cooler surface within a wall structure, water vapour in the air can condense and collect inside these spaces. Moisture can then be absorbed in building materials and cause serious defects. There could be a decrease in the toughness and solidity of wet wooden covering due to rot.

The building becomes structurally damaged as time goes on.
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 You Should Conduct an Air Tightness Test

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. Fossil fuel is burnt to heat up a building. This leads to a discharge of carbon dioxide which increases global warming. When air leakage is controlled, heat loss and energy used by the heating system are reduced. Individuals living in buildings with high levels of air leakage may have medical problems. Houses. Low ventilation and uncontrolled air leaks result in mould growth and moisture which can cause potential health issues. A great option would be to build tight and ventilate right. 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 Your Building Needs an Air Tightness Test

Best practice says that air tightness tests should be carried out early in construction and after the final phase. The test results are used in SAP and SBEM calculations, this impacts the energy rating of new building. Large residential areas do not need each building to be tested. Instead, different types of dwellings are 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.

buildings that have not been tested are assessed for air permeability based on similar dwellings’ test scores +2m3/h/m2 at 50 Pa. Selective testing is not recommended because: i.It is quite tough to achieve the lower air permeability rate set for untested dwellings. ii.The proper air tightness rate for each building in the development cannot be attained, as only some underwent air tightness testing; a tested building might be much tighter than an untested one.

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 Teddington. Because of the following guarantees of working with us, we are highly endorsed by our clients.

Expert information and service

Our experience in serving diverse customers in Teddington is proof of our ability to satisfy your requirements no matter the size and type of building, or your circumstance. Our qualified air tightness testing professionals will work around your schedule, so they fit into your project seamlessly, providing a quality service as conveniently as possible. Do you need trustworthy professionals who will provide great results in Teddington? Contact AF Acoustics today.

Registered Members of the Leading Air Tightness Body in the UK

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.

When to Call Us to Test Your Building

You can access our complete air tightness test in Teddington at anytime. We offer responsive scheduling options. You can schedule for air tightness testing at your convenience. There won’t be delays or complications once you’ve fixed a time.

Next-day Turnaround on Test Certificate Where Possible

Our customers are eager to get their test results. AF Acoustics, which provides reliable, competent services, strives to issue test certificates on the next day.

Fair Pricing

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 Teddington at reduced costs.

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

We Conduct Tests for All Types of Buildings in Teddington

Regardless of the size, type, or complexity of your domestic or commercial building in Teddington, we can provide you with air tightness testing, carried out by an experienced and professional air tightness tester and issue you a certified ATTMA certificate. You can find out how much uncontrolled ventilation your building has by testing it for air leakages. The result of the air leakage test 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 a building envelope.

Air leakage testing is a requirement of 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. Too much air leakage leads to heat loss (and consequently, higher CO2 emissions) and discomfort. It can also create convective loops within a building; this is often referred to as thermal bypassing and wind washing. 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 Teddington. For your commercial building, air tightness testing will ensure your staff and clients are in a comfortable environment. This increases the company’s productivity and lowers heating and cooling expenses.

A Description of Part L Test

Air tightness testing has been a compulsory part of the Building Regulations for new dwellings, renovations and commercial projects since the revision of Document L in 2006. Air tightness is referred to as air permeability or leakage 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. Samples of houses in an area and all non-domestic buildings with more than an area of to m2 must be tested, according to Part L of the Building Regulations. The highest air permeability target set is 10m3/h/m2 but your building might need a much lower one. Air leakage affects the building’s energy performance and is required to meet Building Regulations Part L and measure up to the standard for low carbon buildings.

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.
Get the mechanical extract fans tested for flow rate. This is what Building Regulations Approved Document F requires. Evidence of this test must be passed to the Building Control Body (BCB) as part of their sign-off procedure. There are three alternative methods which can be followed to test, record and report the testing of extractor fans. AF Acoustics employs the minimum benchmark procedure (method 3), which involves using a vane anemometer.


The types of Air Tightness Testing Services 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. Air tightness testing for dwellings more than 4000m3, except big phased handover/zonal and high rise (LCHR) constructions is done. 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

An air leakage test is a test to determine the level of uncontrolled air flow through gaps or cracks in the fabric of a building. The test results are inscribed as m3/h/m2 – (m3 per hour) per square metre. Part L1A of Building Regulations stipulates that such tests be conducted. Your building may need a lower rate to meet the CO2 discharge target. 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.

Approved Document L2A Air Pressure Testing of Commercial Constructions

Air leakage testing is the measurement of uncontrolled ventilation from a building’s fabric. The result is expressed as a quantity in the form of air pressure (m3 per hour) per square metre of building fabric. Part L2A of Building Regulations has demanded that such tests be conducted. 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. 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 Test Your Automatic Opening Vent’s Smoke Shaft

We undertake smoke shaft integrity testing to confirm that the shaft is sufficiently air tight in order to allow the automatic opening ventilation to perform as required when it is fitted and commissioned. When there is a fire, the auto opening vents play an important part in expelling smoke in multi-storey buildings. For the vents and fans to operate at the expected level, the smoke shaft must be air tight to create a difference in air pressure and give emergency services when needed. We’re committed to automatic opening vents builders’ target for air permeability. This enables the vents to work efficiently. An air pressure test is taken for the smoke shaft by installing a fan inside. The intended openings of the shaft (i.e. extract point and openings for ventilation grilles on each floor) are sealed off for the test so that the integrity of the shaft itself can be determined. The fixing and commissioning of the auto opening vents happen after the test is completed.

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. It is important to ensure the ventilation strategy is working effectively. This helps to remove pollutants from the air and control excess humidity, particularly in rooms such as bathrooms and kitchens. 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.

Particular Test and Building Readiness Operation

Air tightness tests calculate the level of air leakage a building has and if it is excessive. Improving the air tightness of a building not only enhances the comfort of the occupants, but can also increases the building’s energy efficiency.

It is difficult to notice unwanted openings in a building envelope. They might be blocked by the internal finishes. If you know the leakage paths of a building, you will know if it is air tight.

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 dwellings be tested, as there is a penalty for developments that are not tested.

What Should You Do Before Testing Your Building?

Our test engineers require the drawings (plans and elevations) and target air permeability requirements of your building before taking the test. 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. Making your building ready by ensuring it has an air tight environment will involve:

  • 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)

Building Envelope Measurement

We undertake the building envelope calculations before we arrive on the site. The building envelope is the surface area of the thermal boundary of the building. The calculations, which are extracted from the drawings, are fed into our estimations when testing your building for air leaks.

Air Barrier 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

Although hardly used as a major deciding factor for calculation or design, air exchange rate is vital in ventilation design. To calculate ventilation rates for domestic buildings, the area and number of people living in the building are considered.

Measuring a Cold Roof Construction’s Envelope Area

This is essential to determine if the roof area is the same as the ground floor area. 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 Construction Envelope Area Calculation

In a warm roof, an air barrier is inside the insulation which runs on the pitched roof rafters. The envelope area, found at the insulation’s warm side, is the separator between the conditioned internal aspect and the unconditioned.

Building Preparation

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

Process for Testing the building

Check all weather conditions such as temperature, wind speed and barometric pressure. Connect a fan to an aperture within the construction envelope. For example, the door. Set up testing equipment. 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. At each fan speed, note the differences in air pressure in all the parts of the building.

Air Leakage Measurement

We analyse the air tightness test data, point out any air leakage path and send a report to clients. If the building fails the test, we suggest remedial measures to the client. Air Leakage Testing and Compliance

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 Lower levels of mould due to less moisture collecting in gaps and cavities. Fewer draughts, causing more comfort 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. Not only do we provide services that meet building regulation targets, when you employ our services, you’ll save money and spend less in the long run. We test for air permeability, provide consultancy services and support services and review the designs of all buildings, whether domestic or commercial, large or small.


Best Practice Procedures

When constructing a new building, it should be built air tight, as stated by Building Regulations – Approved Document L1A. 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 Permeability on Building Fabrics, According to L1 Technical Standard.

Certain technical standards are to be employed during air pressure test in the UK, as specified by ATTMA, building regulations and other documents. BS EN 13829:2001 and ISO 9972:2015 are clarified by the technical standards. The technical standards provide rules that ensure testing organisations get the same results from the same kind of tests and are based on BS EN 13829 “Thermal Performance of Buildings. Determination of air permeability of buildings. Fan pressurisation method” and ISO 9972:2015, “Thermal performance of buildings – Determination of permeability of buildings – Fan pressurization method”.

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

Building Regulation Requirements Part L 2010 (England and Wales)

If you’re constructing a new dwelling, you have to comply with Approved Document L1A’s stipulation to test it. 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. For developments where no more than two dwellings are constructed, it may be possible to avoid the need for any pressure testing by using an assumed value of 15m3/h/m2 within the DER/TER calculations. An SAP assessor can decide which buildings can use the assumed value successfully. ATTMA TSL1 and ATTMA TSL2 prescribe methods for testing occupied and unoccupied buildings. Both residential areas and many non-Dwellings are to take the air leakage test. A building might not have to undertake the air leakage test if its floor space is less than 500m2 or its DET calculations have an air permeability rate of 15 m3/h/m2 added to it.

Building Regulations Part L (England And Wales)

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

Testers can be divided into three types

  • A single fan is the instrument used for the first level to examine single buildings and smaller non-dwellings from 1m3 to 4000m3.
  • 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.

Report for Air Leaks Test

Air leakage test reports are given by authorised organisations that test different buildings. Temporary sealing of extraction units will be done by the tester; all test results will be noted, and a shortened form report will be written which will include the findings of the test. 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. We will ensure the report correctly identifies the tester, customer, building and its address. Where applicable, we will identify pass or failure of your building and provide recommendations for any remedial action or improvement to the building if any further testing is required.

Resources Air Tightness Checklist – Dwelling

Before our test engineers arrive at the site, please adhere to what is written below and send the required air tightness target of your dwelling that is in the design to us.

Air Leakage Pathway 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.