ATTMA Licensed Air Tightness Testing in Bridge-and-Bridge-without

Air tightness testing, also called air leakage testing or air pressure testing, calculates the quantity of air escaping through openings in a building. Air tightness testing became an integral part of building regulations for new buildings, commercial developments and revamped buildings in 2006 after Document L was reviewed.

Because air leakage is the process whereby air escapes through any crack or hole in the building envelope and influences its energy performance, building regulations have been modified to ensure a building has adequate air tightness. 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. Located in Bridge-and-Bridge-without, our company is a committed and accredited air permeability testing service provider; we provide air testing services. You can also call or email us for any of these services:

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

As registered members of the ATTMA, our air tightness certificates are accepted as proof of building regulations sign-off. 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. Our services provide great value for money at high standards.

Our Guarantee

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

Air Tightness Testing – What 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 is the uncontrolled flow of air through gaps and cracks in the fabric (often referred to as infiltration or draughts) and not ventilation, which is the controlled flow of air in and out of the building. 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). When too much air leaks through a building’s fabric, heat loss occurs, making the occupants uncomfortable. Regulations now concentrate on minimising air leakage from the building envelope thereby reducing the amount of fuel burned for maintenance. This helps reduce carbon dioxide emissions. Air tightness testing is important in establishing air leakage from a building’s fabric, the energy efficiency of a new building and in identifying poor build quality within new developments. 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. When the building fabric is properly constructed to reduce air loss, the building is economical, and energy efficient.

Air Leakage Explained

Air leakage is where air enters and leaves a building uncontrollably through cracks and holes in the building fabric. When the circulation of air is properly monitored and bridled, ventilation has occurred. Another name for air leakage is 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 2006, air tightness of newly constructed buildings and non-dwellings with a floor area over 500m² became compulsory in England and Wales.

What Is the Impact of Air Leakage?

Air leakage causes heat loss. Once the atmosphere is cold and windy, unwanted chilly air infiltrates the building through gaps, leading to heat reduction. The infiltration of chilly air causes exfiltration, making warm air within the building escape through the spaces in other parts of the building. 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. The strength of the outer wooden covering is drastically reduced because it is wet.

The building becomes structurally damaged as time goes on.
The inhabitants become uncomfortable because of chilly homes, heating expenses increase and more CO2 is emitted due to the additional heat required.

The best way to reduce the harmful effect of moisture is to efficiently control how air moves into and out of the building. An adequately installed air barrier reduces air leakage and condensation of water vapour on inner wall layers. Correct ventilation is important, whether it is passive or active, to remove water vapour, unwanted moisture odour and pollutants.


Why Should We Do an Air Tightness test?

Air tightness is an important factor in a building’s energy efficiency and is part of government’s plan to battle environmental change by regulating the energy performance of buildings. Heating buildings contribute to global warming and CO2 emissions, since fossil fuels are used to create heat. A reduction in air leakage lessens the heat needed to keep a building warm. 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. Best practice advice is to “Build tight, 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 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. With selective testing there is a penalty of +2m3/h/m2; if the target score is 5 m3/h/m2 and selective testing was applied, the air tightness test would have to achieve a lower score of 3.

Where the dwelling has not been pressure tested, the assessed air permeability is the average test result obtained from other dwellings of the same dwelling type on the development, increased by +2.0 m3/h/m2 at 50 Pa. Because selective testing does not conduct tests for all buildings, a tested building might have a much higher air tight rate than an untested building; making it unreliable. The 2m3/h/m2 penalty added to untested buildings makes the air permeability rate hard to achieve.

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

AF Acoustics air tightness testing professionalism has helped many homes and business owners in Bridge-and-Bridge-without. Our clients highly recommend us for the following reasons.

Great service and expertise

In Bridge-and-Bridge-without, we have served many clients. The experience garnered from our years of service will help us meet your specific needs no matter the size or type of property. Our accredited air testing experts are polite and competent. They are trained to provide the service you need and fit around your project. Do you need trustworthy professionals who will provide great results in Bridge-and-Bridge-without? Contact AF Acoustics today.

Registered Members of the Leading Air Tightness Body in the UK

We are registered with the Air Tightness Testing and Measurement Association (ATTMA), an organisation that is centred on technical excellence in all air leakage measurement methods. ATTMA, the leading air leakage testing body in the UK, has recognised the quality of our services.

Picking a Time for Your Air Permeability Test

Our comprehensive air permeability testing in Bridge-and-Bridge-without is available. We offer responsive scheduling options. You can schedule for air tightness testing at your convenience. We guarantee that there will be no delays or difficulties.

Quick Turnaround on Test Certificates 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.

Affordable Prices

AF Acoustics fees are lower since we’re a company with low overheads. Our services are professional and we offer affordable prices in Bridge-and-Bridge-without.

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 Bridge-and-Bridge-without

We conduct air permeability tests on residential and commercial buildings of all sizes and types. After the test, an ATTMA certificate is given to you. Air tightness test checks the extent of uncontrolled air moving through openings in the building envelope. The results are registered as The test results are described as m3/h/m2 – (m3 per hour) per square metre of building.

Approved Document L1A and L2A requires that buildings know their air permeability rates by taking the air leakage test. 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. Several problems are caused by uncontrolled ventilation. They are:

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

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. 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 Bridge-and-Bridge-without. With air leakage tests, business areas are more comfortable for employees and customers. This increases the company’s productivity and lowers heating and cooling expenses.

A Description of Part L Test

Air tightness testing has been a mandatory part of the Building Regulations for new build and refurbishment projects since Approved Document L was revised in 2006. The air-tightness of a building is known as its ‘air permeability’ or leakage 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. 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. Part L has also set a maximum air permeability target rate of 10m3/h/m2, but a building usually needs lower levels. Air permeability is key in the following areas: i. A construction’s energy performance, ii. CO2 emission targets iii. Building Regulations Part L standards

Part F Test

We will ensure that you exceed all the Parts L and F standards. 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.
New buildings should ensure that all mechanical extract fans are tested for flow rate, as stipulated by Part F of the Building Regulations. 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. We use a vane anemometer, which is the third method called the minimum benchmark method, to conduct extract fan flow rate tests.


Different Ways We Test for Air Permeability

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. Level 3: Air Pressure Testing for LCHR buildings, phased and zonal handover buildings is carried out.

Domestic Buildings Testing as Required by Approved Document L1

Air leakage testing is the measurement of uncontrolled ventilation from a building’s fabric. The result is written as m3 per hour per square metre of building. Document L1A of Building Regulations declares air leakage testing to be mandatory. The carbon discharge requirement for all buildings reduces the air permeability rate target. The required rate can be found in a building’s design-stage SAP assessment SBEM. Air leakage leads to heat loss, increased energy bills, greater CO2 emissions, and an uncomfortable atmosphere for inhabitants due to draughts.

Testing of Air Permeability of Commercial Dwellings, in Accordance with Document L2 Stipulations

The measurement of air emitted by a building is tested to ascertain air permeability rating. The test results are inscribed using m3 per hour per square metre. Air pressure testing is compulsory, according to Approved Document L2A. The test results have a limit; they shouldn’t be higher than 10m3/h/m2. The result of your dwelling’s air permeability rate might have to be lower than required due to SAP or SBEM assessment. You can find the required air permeability rate of your building in its design-stage SAP or SBEM assessment. Uncontrolled air leakage can cause several problems. They are: infiltration of cold air, discomfort, reduction in heat, and higher CO2 emission rate.

We Test Your Automatic Opening Vent’s Smoke Shaft

Smoke shaft needs to be tested because its air tightness determines the performance of the automatic opening vent fitted on it. Our professionals perform the test. Smoke needs to be cleared out in the event of a fire. The automatic opening ventilation is a vital aspect of the fire strategy for high rise buildings. 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. We’re committed to automatic opening vents builders’ target for air permeability. This enables the vents to work efficiently. The shaft is tested for air permeability by using a fan that is fixed inside it. Once the fan is fixed, the extract points and ventilation grilles on each storey are sealed to ensure that the shaft is in proper condition. The fixing and commissioning of the auto opening vents happen after the test is completed.

Air Flow Measurement of Domestic Ventilation (extraction fan testing)

The mandate to construct well insulated and air tight buildings, has made it crucial for satisfactory, enhanced and balanced ventilation systems to be installed. We test fan extraction rates. This is done to meet the Building Regulations standard. Make sure the ventilation system is efficient, expels pollutants and odours, and reduces humidity, especially in kitchens and bathrooms. The air flow rates of all intermittent extractor fans, which are to be installed during the building process, are to be tested and the results submitted to the Building Control Body before work is completed.

Specific Test and Building Preparation Procedure

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. The only satisfactory way to show that a building fabric is airtight is to detect and measure leakage paths within the building fabric.

At least 20% of different kinds of dwellings in a development have to be tested, according to new regulations; but the reliability of the sample from this type of testing is determined by the types of buildings in the development. We recommend that all buildings be tested as those that aren’t are penalised.

What Should You Do Before Testing Your Building?

Clients should send the drawings (plans and elevations) and air permeability requirements to our engineers. An Air tightness test can be done in 30 – 60mins. Wind speed should not exceed 6m/s. Test engineers need to know the size of a building envelope and requirements before coming to the site. Making your building ready by ensuring it has an air tight environment will involve:

  • 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

How We Measure the Building Envelope

We take the building envelope calculations before the test. The building envelope is the surface area of the structural barrier of a building. It separates the interior from the exterior part of the dwelling The measurement is obtained from the construction drawings, and put in our calculations to conduct the test.

Envelope Area Air Permeability

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

The air change rate is important in designing a ventilation system, however, it is hardly a part of the actual design. Residential ventilation rates are measured based on the number of inhabitants and area of residence.

Cold Roof Construction Envelope Area Calculation

This is essential to determine if the roof area is the same as the ground floor area. A cold roof is the kind of roof where the insulation is fixed in the ceiling joists with space between the insulation and 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 is the barrier between the conditioned space in the insulation and the unconditioned space outside.

Preparing the Building

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

Process for Testing the building

Evaluate the weather (barometric pressure, wind speed and temperature) Connect a fan to an opening, like the door, in the building fabric. Ensure all the testing equipment is ready. Record the air volume flow passing through the fan. Gradually increase the speed of the fan to a maximum of 55-60Pa. Record how the air pressure differs at each fan speed.

Evaluating Air Leakage

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: Lower heating bills due to less heat loss, with potentially smaller requirements for heating and cooling equipment capacities The ventilation system will operate optimally Your building will have less mould since moisture cannot escape into holes and cavities. You won’t experience much discomfort because there will be fewer draughts. Our clients can expect a stress-free conformity to Part L Building Regulations standards, whether they have a single building or a large commercial building. They also ensure that you spend less money. Here are the services we provide:

  • Air tightness test
  • Consultancy
  • Design reappraisal
  • Support services

Best Practice Processes

The Building Regulations approved document Part L1A 2010 specifies that any new dwellings must be airtight. The regulation helps to reduce the use of fuel and power. Part L1A states that any new building must undergo an air pressure test, according to present regulations.

Measuring Air Permeability on Building Envelopes (Dwellings) – To Technical Standard L1

ATTMA has specified technical standards that must be adhered to while testing buildings in the UK, according to building regulations and other documents. This Technical Standard provides detailed guidance and clarification of BS EN 13829:2001: “Thermal Performance of Buildings. Determination of air permeability of buildings. Fan pressurisation method” and ISO 9972:2015: “Thermal performance of buildings – Determination of permeability of buildings – Fan pressurization method”, in order to ensure consistency by testing companies.

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

England and Wales: Building Regulation Targets Part L 2010

Approved document L1A has made it compulsory for all new buildings to be tested for air leaks. 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. The method for testing required by the building regulations is stated in ATTMA TSL1 (for dwellings) and ATTMA TSL2 (for non-dwellings). Air leakage testing is compulsory for residential areas and certain Non-Dwellings. 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 Part L (England And Wales)

In January 2015, the ATTMA Scheme for Competent Air Tightness Testing Firms and Their Testers (The ATTMA Scheme) was launched. It is an industry competence scheme authorised by the government and specified in Technical Standard L1 & L2. It mirrors the operation standards and skill requirements set by the National Occupation Standard (NOS) and the Minimum Technical Competence (MTC) document.

Air leakage testers have three levels

  • A single fan is the instrument used for the first level to examine single buildings and smaller non-dwellings from 1m3 to 4000m3.
  • Level 2: Testers can test all buildings except large, complex and or high-rise buildings and or phased handover or zonal buildings unless part of a team managed by a level 3 tester.
  • Level 3: These are air tightness experts who can cover large, complex and or high-rise buildings and or phased handover or zonal compartmentalisation.

Air Tightness Test Report

Authorised companies, who test buildings of different types, sizes and complexities, give air tightness reports. 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. This is done according to the testing organisation’s procedures and Building Regulation standards.

Test Results

AF Acoustics guarantees the test outcome is written in line with standard requirements; it picks out any deviations from the significant benchmarks inside the report and checks air permeability against target values. The identity of the customer, tester, building and address are correctly written in our report. In the event that a building fails the test, we suggest methods of improving the building and what repairs to do on the building fabric if a retest is required.

Resources Air Tightness Checklist – Building

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)

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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.