Norbury Air Tightness Testing, Licensed by AF-Acoustics

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 has been a compulsory part of the building regulations for new dwellings, renovations and commercial projects since the revision of Document L in 2006.

Air leakage occurs through any opening in the building envelope and can affect a building’s energy performance, this has been addressed by changes to the building regulations. AF Acoustics certificates are certified by Air Tightness Testing and Measurement Association (ATTMA). ATTMA is an association of specialists that concentrate on promoting the best air tightness measurements and air permeability testing techniques. AF Acoustics, a licensed air tightness testing company, is available to provide testing services at your request. Our address is Norbury. We also provide Part F mechanical extract fan flow rate testing, assessments and consultancy services.

As registered members of the Air Tightness Testing and Measurement Association, our air leakage test certificate is accepted as evidence for Building Regulations sign-off. If you want specialist air pressure testing services in Norbury, 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

Air Tightness Testing – What It Means

Air tightness testing is a technique whereby a newly constructed building is evaluated and the quantity of air leaking through is measured. It can also be called air pressure testing or air leakage testing. While the normal restrained movement of air all through a building is called ventilation, the unchecked movement of air through cracks and gaps in a building is air leakage; also known as draught or infiltration. Air tightness testing is done to calculate the total quantity of air that escapes through cracks in the building. Such air leakage is called uncontrolled ventilation (draughts). An excessive amount of uncontrolled air loss results in heat reduction, making the residents uncomfortable. The government aims to lessen the quantity of air flowing from newly built buildings. Therefore, regulations have been put in place to reduce uncontrolled ventilation from the building envelope, sustaining the right temperature conditions without using so much fuel. 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. When the building fabric is properly constructed to reduce air loss, the building is economical, and energy efficient.

Air Leakage Explained

This occurs when openings in a building lead to excess air flow into and out of the 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. In England and Wales, air tightness testing has been obligatory since 2006. All new dwellings and non-dwellings over 500m² are to be tested for air permeability.

What Is the Impact of Air Leakage?

When air escapes uncontrollably from a building, heat reduction occurs. Heat loss is caused by influx of frosty outside air into a building through the openings in its envelope during draughts and cold weather, leading to an uncomfortable drop in temperature. Once there’s infiltration, exfiltration will occur in another part of the building. Warm, moist air seeps into cool cavities in the building’s fabric. 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. The strength of the outer wooden covering is drastically reduced because it is wet.

These problems will eventually cause structural harm to the building.
Other damages that can occur are cold homes which make occupants uncomforta-ble, increase in heating bills to make the internal temperature warmer, and more carbon dioxide discharge since additional heat is required.

The best way to reduce the harmful effect of moisture is to efficiently control how air moves into and out of the building. Adequately installed air barriers minimise air leaks and the probability of vapour condensing and diffusing into the building’s structure. Correct ventilation, whether passive or active, ensures fresh air circulates through the building, eliminating water vapour, moist odour and polluting substances.


Why Must We Do an Air Tightness Test?

Air tightness is an integral element of energy efficiency. It is part of government’s plan to overcome climate change through advancements in the energy performance of buildings. Heating buildings contribute to global warming and CO2 emissions, since fossil fuels are used to create heat. The reduction of air leakage leads to lower heat loss and quantity of heat generated in a building. Poor degrees of ventilation and high levels of uncontrolled air leakage encourage mould growth and excessive moisture. This could potentially cause medical issues. To “Construct tight, ventilate right” is the best practice. The result of uncontrollable air moving into the building fabric could be health problems and costly repairs.

When Is an Air Tightness Test Needed?

Best practice says that air tightness tests should be carried out early in construction and after the final phase. The test results are used in SAP and SBEM calculations, this impacts the energy rating of new building. For big residential developments, the test is not required for each house. A group of diverse buildings are picked for the test. 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.

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 You Should Choose AF Acoustics for Your Air Tightness Testing

Numerous businesses and home owners have been aided by AF Acoustics air tightness testing proficient skills in Norbury. Because of the following guarantees of working with us, we are highly endorsed by our clients.

Helpful service and expert knowledge

Our vast experience in serving a variety of clients in Norbury 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. Our personnel will use their expertise to provide lasting solutions. Contact AF Acoustics in Norbury –the right team for your building.

Registered Members of the Leading Air Tightness Body in the UK

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 Can You Call Us to Test Your Building?

Our comprehensive air permeability testing in Norbury is available. We offer responsive scheduling. Schedule for your building to be tested at your convenience. We won’t make you wait or make the process complicated.

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.

Fair Pricing

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

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

We Conduct Tests for All Types of Buildings in Norbury

Whatever the type and size of a domestic or commercial building in Norbury, AF Acoustics’ experts can test it for air permeability and issue an ATTMA certificate afterwards. An air leakage test is used to determine the level of uncontrolled air flow through gaps or cracks in the fabric of a building. The result is expressed as a quantity in the form of The test results are described as m3/h/m2 – (m3 per hour) per square metre. of building fabric.

Approved Document L1A and L2A demands that buildings take tests for air leaks. The maximum air permeability rate is 10m3/h/m2. The carbon discharge requirement for all buildings reduces the air permeability rate target. This target can be found in a building’s design-stage SAP assessment or 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. Exfiltration/infiltration of air is caused by the difference in air pressure inside and outside the building. Lower pressure occurs as warm air rises and brings air inside through any available opening. 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 Norbury. For commercial constructions, air pressure tests result in a better environment for workers and customers. It will also help you reduce the cost of maintaining heating or cooling in your commercial building, making it more productive.

Part L Test Explained

Air tightness testing has been a mandatory part of the Building Regulations for new build and refurbishment projects since Approved Document L was revised in 2006. Air tightness is referred to as 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. To adhere to Part L, make sure your building’s air permeability rate is not greater than 10m3/h/m2. Air permeability is key in the following areas: i. A construction’s energy performance, ii. CO2 emission targets iii. Building Regulations Part L standards

What Is Part F Test?

We can complete all your Part F and Part L testing requirements. Not only will we conduct your air tightness test and extract fan flow rate test, we will also recommend experts who can handle your SAP calculations, water calculations and Energy Performance Certificates satisfactorily.
Approved Document F of the Building Regulations requires that all mechanical extract fans in new dwellings be subjected to a flow rate test. Your building won’t be signed off until Building Control Body (BCB) has been presented the results of the test. There are three alternative methods which can be followed to test, record and report the testing of extractor fans. Using a vane anemometer, our testing procedure follows Method 3 – The minimum benchmark method.


Forms of Air Pressure Testing Services We Provide

There are several levels of air leakage testing based on the kind, size and multifaceted aspects of a dwelling. Here they are: Level One: Testing for the air pressure of single buildings and smaller non-dwellings of 4000m3 gross envelope volume and below, a single blower door fan is used. 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. Level 3: Air Pressure Testing for LCHR buildings, phased and zonal handover buildings is carried out.

Approved Document L1 Air Pressure Testing of Houses

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 tightness testing is required for new builds. A lower air permeability rate might be needed due to carbon emission requirements. The design-stage SAP assessment SBEM of a construction records its required air permeability rate. Too much air leakage leads to heat loss which can lead to draughts and higher energy bills.

Air Tightness Testing of Commercial Buildings to Meet Approved Document L2A Requirements

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. Part L2A of Building Regulations has demanded that such tests be conducted. The highest air permeability rate for your dwelling when tested should be 10m3/h/m2. A building will usually have to achieve a lower rate to meet the SAP or SBEM assessment. To get your building’s required air permeability rate, check its design-stage SAP or SBEM assessment. An excessive amount of air leakage leads to greater energy expenses, heat reduction, carbon dioxide discharge and draughts.

Testing the Smoke Shaft of Automatic Opening Vents

We provide smoke shaft tests to make sure it is air tight enough to let the automatic opening ventilation work optimally when it’s installed and commissioned. Automatic opening vents are crucial during fire emergencies in storey buildings, as they clear out smoke from the 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. The usual openings are closed off too so that the shaft’s integrity can be determined. Smoke shaft tests occur before installing and commissioning automatic opening ventilation.

We Offer 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. Extract fans are tested by us. It is important to ensure the ventilation strategy is working effectively. This helps to remove pollutants from the air and control excess humidity, particularly in rooms such as bathrooms and kitchens. Part F Building Regulations also require standard intermittent extractor fans in new buildings (such as bathroom and kitchen extractors) to have their air flow rates measured on site and the results submitted to the building control body before completion.

Specific Test and Building Preparation Procedure

Air tightness tests calculate the level of air leakage a building has and if it is excessive. The greater the air tightness of a building, the more comfortable the occupants are and the higher its energy performance.

Causes of excess air leakage are often hard to detect. These openings might not be seen because of the internal finishes that have been fixed. The only satisfactory way to show that a building fabric is airtight is to detect and measure leakage paths within the building fabric.

Under the new policies of building developments, the lowest number of domestic buildings developers have to test in an area is 20%. However, this depends on the quantity of different house kinds to ensure there is a regular sample throughout the survey. We recommend that all dwellings be tested, as there is a penalty for developments that are not tested.

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 duration of air pressure testing is 30 to 60 minutes in most cases and the wind speed should not be more than 6m/s. Test engineers need the drawings and air permeability details from clients so that they can know the size of the building envelope and other information before arriving at the building. To get the site ready, make the place air tight by closing and securing all external doors, windows, ventilation and smoke vents. Remember to turn off range cookers or stoves a day before testing as well as mechanical ventilation systems, and fill all drainage traps.

  • Shut the windows
  • Close the smoke vents
  • Open and secure all inner doors
  • Put off the mechanical vents
  • Close ventilation
  • Fill drainage traps
  • Put off range cookers/stoves a day before the test (if applicable)

How We Measure the Building 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. We use the building envelope measurements to get the right results when testing for air tightness.

Air Barrier Envelope Area

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

Air Changes Per Hour

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

It is important to make sure the roof area and ground floor area of a building are equal. 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.

Measuring a Warm Roof Construction’s Envelope Area

A warm roof is a roof where the insulation is installed on top of the roof structure. The envelope area is the barrier between the conditioned space in the insulation and the unconditioned space outside.

Building Preparation

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

Site Test Procedure

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 fan speed from 20-25 Pa to a maximum of 55-60Pa. The pressure differences in the building at each fan speed should be calculated.

Calculating Air Leakage

We analyse the air tightness test data, point out any air leakage path and send a report to clients. If the building fails the test, we suggest remedial measures to the client. 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: Reduced heating expenses because of lower heat loss, with less need for equipment that has high heating ability. The ventilation system will operate optimally Your building will have less mould since moisture cannot escape into holes and cavities. Infiltration of air is reduced and the inhabitants are more comfortable. From the smallest to biggest building or development, we adhere to Building Regulations Part L and Building Standards. We provide air tightness testing, consultancy, design reviews and support services on all buildings, both dwellings and non-dwellings in Norbury. We also provide cost-effective, local service that complies with all relevant Building Standards.


Good and Best Practice Standards

Building Regulation Part L1A 2010 stipulates that all new buildings must have low air permeability. Reduced power usage and fuel conservation are important; that’s why the rule was put in place. Part L1A states that new dwellings should be tested for air tightness in accordance with existing regulations.

Testing for Air Permeability on Building Fabrics, According to L1 Technical Standard.

Certain technical standards are to be employed during air pressure test in the UK, as specified by ATTMA, building regulations and other documents. 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

England and Wales: Building Regulation Targets Part L 2010

Test for air permeability must be conducted on your new constructions. This is stated in Approved Document L1A. Where there are two or more new buildings in an area, conduct a test on 50% of all examples of a kind of dwelling or 3 units of a dwelling kind. Where there are only one or two new buildings, add an assumed value of 15m3/h/m2 to the DET/TER measurements; an air tightness test may not need to be carried out. To find if your building falls into this category, contact your SAP assessor. A testing procedure required by Building Regulations is expressed in ATTMA TSL1 for dwellings and ATTMA TSL2 for non-dwellings. Air leakage testing is compulsory for residential areas and certain Non-Dwellings. A building might not have to undertake the air leakage test if its floor space is less than 500m2 or its DET calculations have an air permeability rate of 15 m3/h/m2 added to it.

Part L Building Regulations Standards for 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. Minimum Technical Competence (MTC) and National Occupation Standard (NOS) documents are the basis for the scheme.

Air pressure testers have three levels

  • Level One: Testing for the air pressure of single buildings and smaller non-dwellings of 4000m3 gross envelope area and below, is done with a single fan.
  • Level Two: Testing for the air pressure is done in all single and multifaceted buildings. High rise (LCHR) buildings and phased handover/zonal buildings are excluded from this level, except a level 3 tester is in charge of the team.
  • Third Level – These experts carry out air tightness testing in large and complex high rise and phased handover buildings.

Air Leakage 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 organisation makes sure the report meets the company and government’s requirements.

Outcome of Air Leak Test

Our test and subsequent results are conducted and written to meet standard requirements, highlight any deviation from the standards and crosscheck air pressure values against target values. Our reports correctly note the client, air tightness tester, building and address. 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 – Dwelling

Go through the list below and send the design air testing permeability value to us before we get to the site.

Air Leakage Pathway List –Ensure you thoroughly check the following equipment. Fill up drainage traps. Here are the pieces of equipment to cover, fill or seal:

  • Extract fans
  • Hoods of cookers
  • Drainage traps
  • Metre boxes
  • Boilers
  • Radiators, fans and heaters
  • Hot water tank
  • Chimney
  • Air bricks
  • Skirting and coving
  • Bath panel
  • Tumble drier extracts
  • MVHR
  • Soil panel

Here are the appliances you should seal temporarily;

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

Air Tightness Testing FAQ’s

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

The common leakage sites are:

All pipe works within the kitchen and bathrooms

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

Our team of experts can support you through the following

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

No. Air tightness testing applies to:

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

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

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

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

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

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

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

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Gerard Finn

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