Air Tightness Testing, Certified by AF-Acoustics, in New-Addington

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. 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. 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. AF Acoustics, a licensed air tightness testing company, is available to provide testing services at your request. Our address is New-Addington. We also provide Part F mechanical extract fan flow rate testing, assessments and consultancy services.

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. Not only do we test the air permeability of your building, we describe the procedure in a professional manner and advise you on problem areas discovered during the evaluation. Our customers get greater value for money spent, and our testing services are of superior quality.

Our Guarantee

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

Air Tightness Testing – What Does It Mean?

Air tightness testing is carried out to determine the volume of air escaping from holes in a building fabric. It is sometimes referred to as air leakage testing or air pressure testing. While the normal restrained movement of air all through a building is called ventilation, the unchecked movement of air through cracks and gaps in a building is air leakage; also known as draught or infiltration. Draughts are uncontrolled ventilation. Using air tightness testing, the total air lost can be estimated. Unrestrained air movement leads to heat reduction, making the inhabitants of the building uncomfortable. The government aims to lessen the quantity of air flowing from newly built buildings. Therefore, regulations have been put in place to reduce uncontrolled ventilation from the building envelope, sustaining the right temperature conditions without using so much fuel. With air tightness testing, you can determine whether or not air is leaking from a building’s envelope, the build quality and energy efficiency of new developments. The building regulations have made air tightness part of the building’s design from the beginning of the construction. This ensures that the fabric of a building is air tight. Incorporating this at the beginning of the construction process makes the development more cost effective and energy efficient.

Air Leakage

Air leakage occurs when air escapes through holes and gaps in a building. 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 plays a major part in the energy efficiency of buildings, and testing is necessary as a means of demonstrating that the air tightness targets used in building energy calculations have been achieved. 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

When air escapes uncontrollably from a building, heat reduction occurs. Heat loss is caused by influx of frosty outside air into a building through the openings in its envelope during draughts and cold weather, leading to an uncomfortable drop in temperature. Once there’s infiltration, exfiltration will occur in another part of the building. Warm, moist air seeps into cool cavities in 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. Wet wooden overlay or framing can decay, decreasing its durability.

As the years go by, these conditions can result in structural damage.
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. An adequately installed air barrier reduces air leakage and condensation of water vapour on inner wall layers. Passive or active ventilation is required to reduce water vapour, moisture odour and pollutants.


Why is an Air Tightness Test Important?

Air tightness is a key factor in building energy efficiency, and is a part of government-led initiative to combat climate change through improvements in building energy performance. Fossil fuel is burnt to heat up a building. This leads to a discharge of carbon dioxide which increases global warming. The reduction of air leakage leads to lower heat loss and quantity of heat generated in a building. Properties with uncontrolled air leakage also cause health issues. A building with poor ventilation and high air permeability is conducive for moisture and mould growth which can affect the inhabitant’s health. The best advice is to “Construct tightly, ventilate properly”. Air leakage causes infiltration of moisture into the building envelope, leading to health issues and high repair costs.

When Your Building Needs an Air Tightness Test

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 results of the test are used in SAP and SBEM calculations, and can influence a building’s overall energy rating. Larger residential developments do not require testing to be completed on each individual property, instead, testing is undertaken on the different dwelling types within the development. Selective testing has a penalty of +2m3/h/m2. If target score is 5m3/h/m2, air tightness test score will have to be 3m3/h/m2.

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. It’s better to test each property because selective testing does not give a realistic picture of individual buildings. Besides, air permeability rates are difficult to achieve for untested buildings in such areas due to the +2m3/h/m2 penalty.

Why 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 New-Addington. Our clients highly recommend us for the following reasons.

Helpful service and expert knowledge

Having served many clients in New-Addington, we have the expertise to work on any type or size of building. Our accredited air testing experts are polite and competent. They are trained to provide the service you need and fit around your project. AF Acoustics is the crew you need in New-Addington to give you the best solutions.

Air Tightness Testing and Measurement Association (ATTMA) Registered

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 Can You Call Us to Test Your Building?

You can access our complete air tightness test in New-Addington at anytime. We offer responsive scheduling. Schedule for your building to be tested at your convenience. We won’t make you wait or make the process complicated.

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

AF Acoustics has professional speedy services to satisfy clients who want their test results immediately. We have a next day turnaround policy for our test certificates and endeavour to deliver in all situations.

Affordable Prices

AF Acoustics, a small business with low overheads, offers one of the best prices in New-Addington and guarantees professional services.

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

Get Air Leakages Test for Homes and Commercial buildings in New-Addington

Regardless of the size, type, or complexity of your domestic or commercial building in New-Addington, 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. Air tightness test checks the extent of uncontrolled air moving through openings in the building envelope. 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.

Air tightness testing is recommended by Approved Document L1A and L2A. A maximum air permeability rate of 10m3/h/m2 is required. However, a building has to achieve a lower rate to meet the carbon emission target. To get your building’s required air permeability rate, check its design-stage SAP assessment SBEM. Excessive air leakage causes discomfort due to heat reduction and carbon dioxide discharge. It also creates convective loops within a building’s internal structure, leading to energy loss. Exfiltration/infiltration of air is caused by a stack effect. Due to the pressure difference inside and outside the building, rising warm air reduces the pressure in the base of the building and draws in air, whether through open doors, windows or other openings 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 New-Addington. Buildings where businesses are conducted will not cause discomfort to employees and clients because they have the legal air permeability rating. This increases the company’s productivity and lowers heating and cooling expenses.

Part L Test Explained

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. The air-tightness of a building is known as its ‘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. To comply with Part L the measured air permeability minimum requirement is 10m3/h/m2 but usually your air permeability target will be much lower. Air tightness is important for meeting the Building Regulations Part L standards, exceeding requirements for low carbon buildings, and overall energy efficiency.

What Is Part F Test?

We can provide you all that you need to serve all your Part L and Part F requirements. In addition to conducting your air pressure test and extract fan flow rate testing, we can put you in contact with professionals who provide SAP calculations, Energy Performance Certificates, and water calculations.
Approved Document F of the Building Regulations demands that all mechanical extract fans in newly completed constructions undergo a flow rate test. The Building Control Body (BCB) has to see the results of the test as part of its sign-off procedure. Examining, documenting and submitting reports of extract fans’ test can be done using three methods. AF Acoustics employs the minimum benchmark procedure (method 3), which involves using a vane anemometer.


Types of Air Leakage Testing Services We Offer

The size, type and multifaceted parts of a building determine the level of air pressure testing it will receive. There are 3 levels and they are listed below. First Level – For building 1m3-4000m3, single and smaller non-dwellings, a single blower door fan is used to carry out the test. Second Level – Testing is done for building 4000m3 and higher, typically simple and complex dwellings. High rise and phased handover buildings are not part of this test. The third level tests big and complex zonal and phased buildings and complex high rise buildings.

Approved Document L1 Air Pressure Testing of Houses

The measurement of air emitted by a building is tested to determine air permeability rating. The result of the air leakage test is expressed as a quantity of air leakage (mm3 per hour) per square metre of building envelope. Air leakage testing is a requirement of Approved Document L1A. In order to comply with the carbon emission target, it is necessary to achieve a lower air permeability rate. The required air permeability rate for a dwelling can be found on the design-stage SAP report for that dwelling. Air leakage leads to heat loss, increased energy bills, greater CO2 emissions, and an uncomfortable atmosphere for inhabitants due to draughts.

Approved Document L2A Air Pressure Testing of Commercial Constructions

The measurement of air emitted by a building is tested to ascertain air permeability rating. The result is written as m3/h/m2 – (m3 per hour) per square metre of building envelope. Part L2A of Building Regulations has demanded that such tests be conducted. The highest air permeability rate for your dwelling when tested should be 10m3/h/m2. A building will usually have to achieve a lower rate to meet the SAP or SBEM assessment. The required air permeability rate for each building can be found on the design-stage SAP or SBEM report for that building. 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

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 help storey buildings dispel smoke when there is a fire. For it to expel smoke from a building and keep the occupants safe during emergencies, the shaft must be air tight enough to create substantial pressure difference. 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. Then the openings are sealed off in all its parts so that the shaft can be thoroughly examined. Once the test is completed and successful, the automatic opening vents are installed.

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 evaluate 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. 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.

Specific Test and Building Preparation Procedure

The measurement of air pressure in a building is known as an air tightness test. When air leakage is reduced in a building, the occupants will not experience discomfort and the energy performance will increase.

External claddings and the internal building finishes might obscure a gap in the building fabric. This makes it hard to notice and can results to potential air leakage. The most acceptable approach to show that a building fabric is impermeable is to identify leakage paths within it.

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. Buildings that don’t undergo the test are penalised. All dwellings in a development should be tested to ensure optimum air tightness.

Pre-Test Requirements

Send the drawings of your dwelling (plans and elevations) and its target air permeability requirements to our test engineers. The duration of air pressure testing is 30 to 60 minutes in most cases and the wind speed should not be more than 6m/s. Test engineers need the drawings and air permeability details from clients so that they can know the size of the building envelope and other information before arriving at the building. 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)

Measuring the Building’s 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 calculations are taken from the drawings. These are then incorporated into our calculations when we air test the property.

Air Barrier Envelope Area

Approved Document L1A Conservation of Fuel and Power in New Dwellings (2010) defines air permeability as “air leakage rate per hour per square metre of envelope area at the test reference pressure differential of 50 pascals (50n/m2)” and envelope area as “the total area of all floors, walls and ceilings bordering the internal volume that is the subject of the pressure test. This includes walls and floors below external ground level. Overall internal dimensions are used to calculate this envelope area and no subtractions are made for the area of the junctions of internal walls, floors and ceilings with exterior walls, floors and ceilings.”

Air Exchange 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. Residential ventilation rates are calculated based on area of the residence and number of occupants.

Evaluating a Cold Roof Envelope Area

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.

Calculating the Envelope Area of a Warm Roof

A warm roof has the insulation running along the pitched roof rafters with an air barrier normally running parallel along the inside face of the insulation. The envelope area, found at the insulation’s warm side, is the separator between the conditioned internal aspect and the unconditioned.

Getting the Building Ready

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

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. Fix the instrument for testing. Calculate the air flow volume through the fan which equates to the air leakage. Raise the fan speed from 20-25Pa to the highest speed of 55-60Pa. Record how the air pressure differs at each fan speed.

Air Leakage Calculation

Our competent engineers note the points of air leakage, examine the test data and send test results to the customer in a technical report. If the test fails, we inform clients on what to do about it. Testing for Air Permeability and Following Part L Building Regulations

Making sure your building is air tight and has adequate ventilation, be it natural, mechanical, or a combination of the two, will aid your comfort. Find below the benefits: Reduced heating expenses because of lower heat loss, with less need for equipment that has high heating ability. Your ventilation system will operate in a better way Less mould will be trapped in the building fabric as a result of less moisture. Thermal comfort is enhanced because air infiltration is lower. 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 New-Addington. We are cost effective and adhere to all building regulations.


Best Practice Procedures

Building Regulation Part L1A 2010 stipulates that all new buildings must have low air permeability. The regulation is focused on the conservation of fuel and power usage. Part L1A states that any new building must undergo an air pressure test, according to present regulations.

Air Tightness Testing of Dwellings That Meet Technical Standard L1L1

There are technical standards for air tightness test of buildings in the UK detailed by Air Tightness Test and Measurement Association (ATTMA). 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 Part L 2010 (England and Wales)

Test for air permeability must be conducted on your new constructions. This is stated in Approved Document L1A. For developments of two or more dwellings, an air leakage test should be carried out on the three units of each dwelling type; or 50% of all instances of that dwelling type. 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. Non-Dwellings and residential buildings are required to test for air leakage. Non-dwellings with a typical floor area less than 500m2 may be exempt. Where testing is not carried out, an assessed air permeability of 15 m3/h/m2 must be used in calculations.

Building Regulations for England and Wales, Part L

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

Air pressure testers have three levels

  • Air tightness testing for single buildings and smaller non-dwellings not more than 4000m3 is done with a fan.
  • The second level examines simple and complex buildings greater than 4000m3, with the exclusion of large zonal buildings and complex high-rise buildings unless a level three tester is in charge of the procedure.
  • Third Level – These experts carry out air tightness testing in large and complex high rise and phased handover buildings.

Air Tightness Test Report

Authorised companies, who test buildings of different types, sizes and complexities, give air tightness reports. Sealed extraction fans are sealed for testing and the details and results of the test are written in a report afterwards. The report is in line with the company’s testing process set by government regulations and all relevant governing bodies.

Outcome of Air Leak Test

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. Our reports correctly note the client, air tightness tester, building and address. If a building fails the test, we provide remedial suggestions before a retest is carried out.

Resources Air Tightness Checklist – Dwelling

Before we arrive on site, ensure you have sent us the air permeability target and been through the checklist below and the ones we have sent you. This will greatly facilitate the process.

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.

Here are the appliances you should seal temporarily;

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

Air Tightness Testing FAQ’s

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

The common leakage sites are:

All pipe works within the kitchen and bathrooms

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

Our team of experts can support you through the following

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

No. Air tightness testing applies to:

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

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

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

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

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

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

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

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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.