Highlands-Village Air Tightness Testing Certified by AF-Acoustics

Air tightness testing, also known as air leakage testing or air permeability testing, establishes the rate at which air flows out of gaps in a building 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.

The energy performance of a building can be affected by air leakage. To address this problem, alterations to building regulations have been made. 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 Highlands-Village. 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. If you want specialist air pressure testing services in Highlands-Village, AF Acoustics’ tightness testing services will

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

Our goal is always value for money and customer satisfaction. We are professionals and our services are of the highest 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

What is Air Tightness Testing?

Air tightness testing is a method of measuring the extent to which air is lost through leaks in the building fabric. It can also be called air pressure testing or air leakage testing. Air leakage is the draught or infiltration of unbridled air through the spaces and openings in a building. It is different from ventilation, which is the contained circulation of air within and outside 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). Unrestrained air movement leads to heat reduction, making the inhabitants of the building 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 vital in determining the energy efficiency of a new building, air leakage and the build quality. Most building designs take air pressure into account at the beginning of construction in order to have an air-tight envelope and measure up to the required standards. Understanding this at an early stage can make a build cost-effective, of high quality, and energy efficient by minimising uncontrolled air leakage.

Air Leakage Explained

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. It may cause uncontrolled influx of air during frosty and windy weather. This reduces the temperature of the building, making the occupants uncomfortable. How do you know if a building is energy efficient? By testing its air permeability. This lets the occupants know if the building meets standard air-tightness requirements. All commercial buildings over 500m² and new buildings in England and Wales are mandated to test for air tightness and permeability, according to the 2006 Building Regulations.

Effects of Air Leakage

Air leakage causes heat loss. 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. The infiltration of chilly air causes exfiltration, making warm air within the building escape through the spaces in other parts of the building. 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. Wet wooden framing or sheathing can rot and break down, diminishing its strength.

As the years go by, these conditions can result in structural damage.
Air leakage can also cause these problems:

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

Successfully managing the movement of air into and outside the building will limit the damaging effects of moisture. A properly installed air barrier minimises air leakage, which, in turn, minimises the potential for water vapour to condense on vulnerable wall structures. To get rid of pollutants, water vapour and moisture odour, the building must be well ventilated.


The Importance of Air Tightness Test

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. Environmental change caused by carbon dioxide emissions and global warming is partly aided by the burning of fossil fuels to generate heat. A reduction in air leakage lessens the heat needed to keep a building warm. Poor degrees of ventilation and high levels of uncontrolled air leakage encourage mould growth and excessive moisture. This could potentially cause medical issues. Building tightly and ventilating the right way is highly recommended. High degrees of air leaks cause huge problems such as expensive remedial work on the building and medical problems.

When Your Building Needs an Air Tightness Test

It is best practice to conduct at least two air tightness testing procedures, one early in the build and another at the end. The test results are used in SAP and SBEM calculations, this impacts the energy rating of new building. It’s not a necessity to perform tests on each property, rather, different kinds of houses are selected and tested. This type of testing attracts a penalty of +2m3/h/m2, consequently, if the target result is 5m3/h/m2, a lower score of 3 would have to be attained.

If the building has not been tested for air tightness, assessed air permeability rate is the average result of similar buildings in the area +2m3/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.

Why AF Acoustics Is the Right Choice for Your Air Tightness Testing

Business owners and home owners in Highlands-Village have been helped by AF Acoustics air tightness testing. We are recommended by our clients for the following reasons.

Helpful service and expert knowledge

Our vast experience in serving a variety of clients in Highlands-Village guarantees we have the expertise to satisfy your needs regardless your unique circumstances, type or size of property. Our qualified air tightness testing professionals will work around your schedule, so they fit into your project seamlessly, providing a quality service as conveniently as possible. AF Acoustics is the crew you need in Highlands-Village to give you the best solutions.

Registered by the Leading Air Tightness Body in UK

AF Acoustics is a member of ATTMA, an association of specialists that concentrates on promoting the best air tightness measurements and air permeability testing techniques. It is the leading air permeability testing body in the UK and has recognised our competence and services.

Picking a Time for Your Air Permeability Test

Our comprehensive air permeability testing in Highlands-Village is available. Simply fix a convenient time for your building’s air permeability test. We offer responsive scheduling. There won’t be delays or complications once you’ve fixed a time.

Quick Turnaround on Test Certificates Where Possible

AF Acoustics offers a professional and reliable service; we understand that our clients are keen to get their test results as quickly as possible, to facilitate this process we strive to deliver next-day turnaround on test certificates.

Affordable Fees

AF Acoustics fees are lower since we’re a company with low overheads. Our services are professional and we offer affordable prices in Highlands-Village.

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

Air Tightness Tests for Any Kind of building in Highlands-Village

Whatever the type and size of a domestic or commercial building in Highlands-Village, AF Acoustics’ experts can test it for air permeability and issue an ATTMA certificate afterwards. Air permeability testing calculates how much air moves through spaces in your building’s fabric. The result of the air leakage test is expressed as a quantity in the form of The test results are described as m3/h/m2 – (m3 per hour) per square metre. of a building envelope.

Air leakage testing is a requirement of Approved Document L1A and L2A. Although your building is required to have a rating result of 10m3/h/m2, the actual result might have to be lower than that due to carbon emission requirements. You can find the required air permeability rate of your building in its design-stage SAP assessment or SBEM. With air leakage comes heat loss, greater CO2 discharge, draughts, thermal bypassing and wind washing and poor energy performance. 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 permeability testing is a legal requirement for constructions in Highlands-Village. This way, they can have high energy performance, meet building regulations requirements and get signed off by building control. For commercial constructions, air pressure tests result in a better environment for workers and customers. This increases the company’s productivity and lowers heating and cooling expenses.

A Description of Part L Test

Since Approved Document L was reviewed in 2006, building regulations have demanded that new and rehabilitated constructions conduct air tightness test. The air-tightness of a building is known as its ‘air permeability’ or leakage rate. Any hole or crack in a building fabric is a spot where air leak can take place. Air leakage points are not often 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. 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.

Part F Test Explained

We will help you with all your Parts L and F requirements. We deliver quality air permeability and extract fan flow rate testing, and also recommend skilled experts who will handle your water calculations, SAP calculations and Energy Performance Certificates.
Get the mechanical extract fans tested for flow rate. This is what Building Regulations Approved Document F requires. The Building Control Body (BCB) has to see the results of the test as part of its sign-off procedure. There are three alternative methods which can be followed to test, record and report the testing of extractor fans. AF Acoustics employs the minimum benchmark procedure (method 3), which involves using a vane anemometer.


The types of Air Tightness Testing Services We Offer

There are several levels of air leakage testing based on the kind, size and multifaceted aspects of a dwelling. Here they are: 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 Three: At this level, tests for the air pressure of high rise (LCHR) buildings and phased handover/zonal buildings.

We Offer Air Leakage Testing of Apartments and Houses to Meet Approved Document L1 Standard

The measurement of air emitted by a building is tested to determine air permeability rating. 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 design-stage SAP assessment SBEM of a construction records its required air permeability rate. Uncontrolled ventilation can cause several problems. They are: infiltration of cold air, reduction in heat, more CO2 emission and higher energy costs.

Approved Document L2A Air Pressure Testing of Commercial Constructions

Air pressure testing involves the calculation of air escaping through the openings in a building. The test results are inscribed using m3 per hour per square metre. Air leakage testing is a requirement of Approved Document L2A. The highest air permeability rate for your dwelling when tested should be 10m3/h/m2. In order to comply with the SAP assessment, it may be necessary to achieve a lower air permeability rate. You can find the required air permeability rate of your building in its design-stage SAP or SBEM assessment. An excessive amount of air leakage leads to greater energy expenses, heat reduction, carbon dioxide discharge and draughts.

Air Leakage Test of Smoke Shafts for Auto Vents

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. Automatic opening vents are crucial during fire emergencies in storey buildings, as they clear out smoke from the buildings. For the fans and vents to perform as required, the shaft itself must be sufficiently air tight so as to create the pressure difference to draw smoke out of the building and protect the occupants. 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. This test is conducted before the automatic opening ventilation is fixed and commissioned.

Domestic Ventilation Air Flow Testing (Extract Fans)

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 are able to test 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. Another of such targets, as stated by Part F, is to have the standard intermittent extractor fans, like kitchen and bathroom extractors, in new constructions measured for air flow and results given to Building Control before the construction work is completed.

Particular Test and Building Readiness Operation

An air tightness test measures the extent of air leakage in a building. When air leakage is reduced in a building, the occupants will not experience discomfort and the energy performance will increase.

Gaps and cracks in the building that cause air leakage are often difficult to detect. They may be obscured by the internal building finishes. The best solution to demonstrate a building’s air tightness level is to check for leakage paths in the building envelope.

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. 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

The client needs to send our test engineers the drawings of the development (plans and elevations) and target air permeability requirements. 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. 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

Measuring the Building’s Envelope

Before coming to the site, we get the measurement of the building’s envelope. A building envelope is the boundary between the conditioned and unconditioned environment of a building. The calculations are taken from the drawings. These are then incorporated into our calculations when we air test the property.

Air Permeability of the Envelope Area

Air permeability is calculated at air leakage rate per square metre of envelope area. In relation to air permeability, the air envelope area is the total area of the measured part of the building without subtracting from the area of the junction of internal walls, or floors and ceilings. The envelope area of a terraced house includes the party walls while that of a flat in a multi-storey building includes shared ceilings, walls and floors.

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.

Calculating the Envelope Area of a Cold Roof

The area of the roof and ground floor should be the same. A cold roof has the insulation at the horizontal ceiling level and a large void or space between the insulation and the pitched roof rafters.

Warm Roof Envelope Area Measurement

A warm roof 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.

Building Preparation

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

Process for Testing the building

Examine the wind speed, barometric pressure and temperature. Connect a fan (or fans) to an aperture in the building envelope (e.g. door). Set up the testing gear. Record the air volume flow through the fan (this equals the air leaking through the building envelope). Raise the fan speed from 20-25Pa to the highest speed of 55-60Pa. The pressure differences in the building at each fan speed should be calculated.

Calculating Air Leakage

We can determine where air leakage is occurring through our test procedure. Once the test has been completed, we crosscheck the data and send a report to you. If the test fails, we will advise you about corrective measures. Air Pressure Testing & Compliance

When a building has the right kind of ventilation (mechanical, natural or a combination of both) and has a low permeability rate, the advantages to the occupants are numerous. Some of them are: The occupants will pay less for heat because less heat is lost and they won’t need equipment with high heating capacities. The ventilation system will operate optimally Your building will have less mould since moisture cannot escape into holes and cavities. Thermal comfort is enhanced because air infiltration is lower. Our air leakage tests are conducted according to building regulations and targets, whether we’re testing a small dwelling or big commercial development. We provide air tightness testing, consultancy, design reviews and support services on all buildings, both dwellings and non-dwellings in Highlands-Village. We also provide cost-effective, local service that complies with all relevant Building Standards.


Good and Best Practice Standards

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. Part L1A states that new dwellings should be tested for air tightness in accordance with existing regulations.

Testing for Air Tightness in Building Fabrics of Dwellings to Adhere to Technical Standards 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

Building Regulation for England and Wales, Part L 2010

Approved document L1A has made it compulsory for all new buildings to be tested for air leaks. 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. If the development has one or two dwellings only, an air tightness test might not be taken if the DET/TER calculations assume a value of 15m3/h/m2. Find out from your SAP assessor if this is applicable to you. ATTMA TSL1 and ATTMA TSL2 prescribe methods for testing occupied and unoccupied buildings. Air tightness tests are to be carried out on all residential developments (all the buildings or a selected group) and all certain Non-Dwellings. If your building has added an estimated assessed rate of 15 m3/h/m2 in its calculations or its useful floor space is less than 500 m2, it may not have to take the test.

Building Regulations Part L (England And Wales)

ATTMA has a competent scheme for air leakage testing firms which determines their level of competence. The scheme, which was launched in January 2015, is recognised by the government and noted in the building regulations. Minimum Technical Competence (MTC) and National Occupation Standard (NOS) documents are the basis for the scheme.

Air pressure 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.
  • 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

Accredited testing companies issue air pressure reports. Sealed extraction fans are sealed for testing and the details and results of the test are written in a report afterwards. The report adheres to the company’s methods and all standards and requirements of Building Regulations.

Results of the Test

AF Acoustics will make sure the result is written in line with test requirements, detect any part of the test that is not in line with the standards required and check actual air tightness against required rate. Our reports correctly note the client, air tightness tester, building and 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 – 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.