ATTMA Licensed Air Tightness Testing in Marks-Gate

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. Our certificates are registered with the Air Tightness Testing and Measurement Association (ATTMA), an organisation that guarantees technical excellence in all air leakage measurement methods. AF Acoustics, a licensed air tightness testing company, is available to provide testing services at your request. Our address is Marks-Gate. 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 don’t just provide air tightness testing. We describe the process thoroughly, give expert advice on areas that could be problematic during testing, and suggest improvements based on the air permeability rating of the building. 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 – What Does It Mean?

Air tightness testing involves calculating the quantity of air which escapes through holes in the building fabric. It can also be called 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 evaluates the complete air leakage a building has in every gap available. The air leakage is known as uncontrolled ventilation. Once too much air escapes, heat reduction occurs, causing the temperature of the building to drop to a level that isn’t comfortable for those residing in it. Air leakage from buildings causes heat loss, more energy is then used to keep the building warm, this is a cause of excess CO2 emissions. This has resulted in regulations which are centred on decreasing air leaks from the building fabric, therefore lowering CO2 emissions. Air tightness testing is vital in determining the energy efficiency of a new building, air leakage and the build quality. With the introduction of tougher regulations, building designs will often consider air tightness at the early stages of the construction process, ensuring attention to detail during construction to create an air-tight envelope. 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 Is Air Leakage?

This occurs when openings in a building lead to excess air flow into and out of the building. It is not the same as ventilation which is regulated air flowing into a building. It is also called infiltration. It may cause uncontrolled influx of air during frosty and windy weather. This reduces the temperature of the building, making the occupants uncomfortable. 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.

What Are the Problems Air Leakage Can Cause?

When air escapes uncontrollably from a building, heat reduction occurs. During windy weather, cold air infiltrates a building through the openings in its fabric. This results in heat loss. 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. Once the moist air reaches the colder internal layer of the wall structure, the vapour in it condenses and forms droplets of liquid, which drawn into building materials and can potentially start a multitude of structural problems. There could be a decrease in the toughness and solidity of wet wooden covering due to rot.

These problems will eventually cause structural harm to the building.
Air leakage can also cause these problems:

  • Colder homes that result in discomfort
  • Higher heating expenses
  • Reduction in CO2 emissions’

These effects can be mitigated by controlling the circulation of air into and out of the building. A properly installed air barrier minimises air leakage, which, in turn, minimises the potential for water vapour to condense on vulnerable wall structures. Correct ventilation is important, whether it is passive or active, to remove water vapour, unwanted moisture odour and pollutants.


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. Environmental change caused by carbon dioxide emissions and global warming is partly aided by the burning of fossil fuels to generate heat. The best way to reduce the quantity of fossil fuel burnt is by stopping air leakage which reduces heat loss. There are also health issues associated with uncontrolled air leakage. When a building has poor levels of controlled ventilation and high levels of uncontrolled air leakage, this can cause excessive moisture and mould growth, leading to poor health. Best practice advice is to “Build tight, ventilate right”. Excess air leakage leads to moisture in the building envelope, causing large repair expenses and medical issues because of mould.

Recommended Period for Air Tightness Test

Best practice dictates that you complete an air tightness test early in the build process, and then again after the construction process is completed; although not all builds have the first test phase. The results of the test can affect a building’s energy ratings because they play a part in SBEM and SAP calculations. 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. Once every building in the residential development is not tested, the expected test result would have to be lowered by 2m3/h/m2. If 5m3/h/m2 was your target score, you must achieve 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. 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 Marks-Gate. Our customers highly recommend us to other people due to the following benefits.

Helpful service and information

Our vast experience in serving a variety of clients in Marks-Gate guarantees we have the expertise to satisfy your needs regardless your unique circumstances, type or size of property. Our accredited air testing experts are polite and competent. They are trained to provide the service you need and fit around your project. Do you need trustworthy professionals who will provide great results in Marks-Gate? Contact AF Acoustics today.

Registered member of the Air Tightness Testing & 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.

When to Call Us to Test Your Building

We want to provide detailed air permeability testing in Marks-Gate for you whenever you need it. We offer responsive scheduling options. You can schedule for air tightness testing at your convenience. We guarantee no delays or complications regarding scheduling.

Quick Turnaround on Test Certificates Where Possible

AF Acoustics offers trustworthy and expert services. We know that clients want to receive their test results quickly. As a result, we endeavour to deliver test certificates by the next day.

Affordable Fees

AF Acoustics offers competitive fees in Marks-Gate. Since we’re a small business, we offer less expensive air permeability testing and render high quality services.

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

Get Air Leakages Test for Homes and Commercial buildings in Marks-Gate

All domestic and commercial buildings in Marks-Gate 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. The best way to determine how much air seeps through a building’s fabric is through air permeability testing. The results are registered as The test results are described as m3/h/m2 – (m3 per hour) per square metre of building.

Air leakage testing is required 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. 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. The warm air within a building rises, leading to the influx of cold air through gap, cracks and other openings in the building envelope. The increasing difference in air pressure results in infiltration and exfiltration of air. To limit exfiltration and infiltration, the law requires that domestic buildings take air leakage tests. The buildings must be energy efficient and signed off by building control in Marks-Gate. 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.

A Description of Part L Test

Air tightness testing is a Building Regulations obligation for new buildings, commercial developments and revamped buildings. This was put into effect in 2006 after Document L was reappraised. Air tightness can also be called air leakage or air permeability rate. Air 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. Part L of the Building Regulations requires that all commercial buildings greater than 500m2 undergo air tightness testing and a selection of residential buildings in a development be tested. Part L has also set a maximum air permeability target rate of 10m3/h/m2, but a building usually needs lower levels. Air tightness is important for meeting the Building Regulations Part L standards, exceeding requirements for low carbon buildings, and overall energy efficiency.

A Description of Part F Test

All your Part L and Part F testing requirements can be met by us. 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.
Approved Document F of the Building Regulations demands that all mechanical extract fans in newly completed constructions undergo a flow rate test. Evidence of this test must be passed to the Building Control Body (BCB) as part of their sign-off procedure. Examining, documenting and submitting reports of extract fans’ test can be done using three methods. Use method 3 – the minimum benchmark method, which tests extractor fans with vane anemometers. This is our testing procedure.


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. Level 1: Air pressure testing for single dwellings and other smaller non-dwellings up to 4000 m³ gross envelope volume, typically tested with a single blower door fan. 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. Third Level – Testing is done for large high rise and phased handover buildings.

Approved Document L1 Air Pressure Testing of Houses

Air pressure testing, involves the calculation of air escaping through openings in a building. The result is written as m3/h/m2 – (m3 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. Excess air leakage causes heat loss and discomfort due to the influx of cold air, also causing increased energy bill expense.

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

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 result is written as m3/h/m2 – (m3 per hour) per square metre of building envelope. Air pressure testing is compulsory, according to Approved Document L2A. The maximum air permeability rate for a dwelling tested is 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. Uncontrolled air leakage can cause several problems. They are: infiltration of cold air, discomfort, reduction in heat, and higher CO2 emission rate.

We Offer Smoke Shaft Air Pressure Testing

We test the integrity of the smoke shaft to ensure the automatic opening ventilation is placed in the best condition. Automatic opening vents are crucial during fire emergencies in storey buildings, as they clear out smoke from the 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. We’re committed to automatic opening vents builders’ target for air permeability. This enables the vents to work efficiently. Fans are placed in the smoke shaft to conduct an air tightness test. The usual openings are closed off too so that the shaft’s integrity can be determined. Once the test is completed and successful, the automatic opening vents are installed.

Air Flow Measurement of Domestic Ventilation (extraction fan testing)

With the legal requirement for buildings that have the right quantity of air pressure, adequate ventilation that is suitable, effective and of high quality has become crucial. We evaluate extraction rates. This is done to meet the Building Regulations standard. Make sure the ventilation system is efficient, expels pollutants and odours, and reduces humidity, especially in kitchens and bathrooms. 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.

Air Tightness Test and Building Preparation Method

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.

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. 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 buildings be tested as those that aren’t are penalised.

Requirements before the Test

Send the drawings of your dwelling (plans and elevations) and its target air permeability requirements to our test engineers. The test engineers would like to have the information needed for the test before coming to your development. Our air leakage test is done between 30 and 60 minutes, and the wind speed is a maximum of 6m/s. To prepare the site for the test, do the following:

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

Building Envelope Measurement

Before coming to the site, we get the measurement of the building’s envelope. The building envelope is the physical separator between the indoors and outdoors. The building envelope calculations are taken from the drawings and used for our air tightness testing.

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

Calculating the Envelope Area of a Cold Roof

When evaluating the roof area of a building, it is important to ensure the area is the same as that of the ground floor. A cold roof is a roof that has its insulation in the ceiling and there’s a huge space between the insulation and rafters.

Evaluating a Warm Roof Envelope Area

A warm roof is a roof system where the insulation is fixed along the rafters with an air barrier inside the insulation. In the warm part of the insulation, is the barrier between the conditioned and unconditioned space.

Building Preparation

  • Open and secure all internal doors;
  • Close all windows;
  • Switch off all mechanical ventilation systems;
  • Seal vents;
  • Close smoke vents;
  • Fill all drainage traps; check weather conditions (wind speed, temperature, barometric pressure);

How the Test Is Done

Examine the wind speed, barometric pressure and temperature. Connect a fan to an opening, like the door, in the building fabric. Fix the instrument for testing. Using the fan, measure the air flow volume, from the building fabric. Gradually increase the speed of the fan to a maximum of 55-60Pa. The pressure differences in the building at each fan speed should be calculated.

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 Tightness & Meeting Part L Standards

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: Your heating expenses are less because heat doesn’t escape through a permeable building, and you won’t require appliances with more heating capability. A functional ventilation system Lower probability of mould because moist air won’t condense in the openings in the building envelope. You won’t experience much discomfort because there will be fewer draughts. From the smallest to biggest building or development, we adhere to Building Regulations Part L and Building Standards. We render cost-effective services that include air leakage tests, design reappraisal, consultancy and support services for dwellings and non-dwellings in Marks-Gate.


Good & Best Practice Methods

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 Tightness in Building Fabrics of Dwellings to Adhere to Technical Standards L1

There are technical standards for air tightness test of buildings in the UK detailed by Air Tightness Test and Measurement Association (ATTMA). The technical standards ensure that all companies have similar testing procedures. They are:

  • “Thermal Performance of Buildings. Determination of air permeability of buildings. Fan pressurisation method” BS EN 13829:2001, and
  • “Thermal performance of buildings – Determination of permeability of buildings – Fan pressurization method” ISO 9972:2015
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)

Undergoing an air tightness test is compulsory for your new building, according to Part L of Building Regulations. 50% or 3 units of each dwelling type should undergo an air leakage test in the case of an area with two or more dwellings. 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. A testing procedure required by Building Regulations is expressed in ATTMA TSL1 for dwellings and ATTMA TSL2 for non-dwellings. 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.

England and Wales: Building Regulations Part L

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.

There are three levels of testers:

  • 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 Three: Testing for the air pressure of high rise (LCHR) buildings, phased handover/zonal buildings and other complex buildings is carried out by level three experts.

Air Leakage Test Report

Test reports are issued by registered and licensed air tightness companies who test buildings of different sizes and complexities. First, extraction fans are closed. Then, the details and results of the tests are written down in a report. The report is in line with the company’s testing process set by government regulations and all relevant governing bodies.

Test Outcomes

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. We will ensure the report correctly identifies the tester, customer, building and its address. We will state if your building has passed or failed the test and give advice on the actions you need to take if another test is needed.

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 Permeability Pathway Checklist – Use this checklist to make sure you are ready for the test. Ask yourself, “Have I sealed any visible opening?” Check the following appliances.

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

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)

Load More

Image module

Gerard Finn

AF Acoustics lead air tightness testing Specialist, Gerard is your first port of call for all air tightness questions enquiries and surveys.