ATTMA Licensed Air Tightness Testing in Benhilton

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. 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.

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. As a certified air leakage testing company in Benhilton, we are ready to provide testing services whenever you want. You can also contact us for assessments and consultancy services. In addition to air leakage testing, we provide Part F Mechanical extract fan flow rate testing.

Our air leakage test certificate is approved by ATTMA and is an indication that a building has been signed off by building control. We provide air leakage testing in a professional manner by explaining the testing procedures and highlighting leakage areas in the building fabric. We also suggest long-term remedies based on the results of the tests. 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 the Assessment of a Building’s Air Tightness?

Air tightness testing involves calculating the quantity of air which escapes through holes in the building fabric. Other names for air tightness testing are air leakage testing and air pressure 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 evaluates the complete air leakage a building has in every gap available. The air leakage is known as uncontrolled ventilation. An excessive amount of uncontrolled air loss results in heat reduction, making the residents uncomfortable. Because the government is striving to scale back carbon dioxide discharge from new buildings, building rules now focuses on reducing air loss from the building envelope. This helps reduce CO2 emissions. With air tightness testing, you can determine whether or not air is leaking from a building’s envelope, the build quality and energy efficiency of new developments. With the introduction of tougher regulations, building designs will often consider air tightness at the early stages of the construction process, ensuring attention to detail during construction to create an air-tight envelope. This can make a building more energy efficient since air leakage is under control. It will also be cost effective and of high quality.

What Air Leakage Is

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. Air tightness testing is compulsory for all new constructions and non dwellings with a floor area over 500m² in England and Wales. This came into effect in 2006.

The Impact of Air Leakage

Air leakage leads to heat reduction. 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. It doesn’t stop there. Warm, damp air within the building escapes the gaps in its envelope. Once the moist air reaches the colder internal layer of the wall structure, the vapour in it condenses and forms droplets of liquid, which drawn into building materials and can potentially start a multitude of structural problems. There could be a decrease in the toughness and solidity of wet wooden covering due to rot.

Over time, any of these conditions can cause structural damage.
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.

These effects can be mitigated by controlling the circulation of air 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.


The Importance of Air Tightness Test

The energy performance of a building is determined by how air tight it is. Energy performance affects CO2 released from buildings. As a result, air tightness testing is a method government has devised to regulate climate change. Fossil fuel is burnt to heat up a building. This leads to a discharge of carbon dioxide which increases global warming. When air leakage is controlled, heat loss and energy used by the heating system are reduced. There are also health issues associated with uncontrolled air leakage. When a building has poor levels of controlled ventilation and high levels of uncontrolled air leakage, this can cause excessive moisture and mould growth, leading to poor health. Building tightly and ventilating the right way is highly recommended. Air leakage causes infiltration of moisture into the building envelope, leading to health issues and high repair costs.

When Is an Air Tightness Test Needed?

It is best practice to conduct at least two air tightness testing procedures, one early in the build and another at the end. Newly completed constructions’ energy ratings can be influenced by the test results, as they are used in SAP and SBEM calculations. For big residential developments, the test is not required for each house. A group of diverse buildings are picked for the test. 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.

buildings that have not been tested are assessed for air permeability based on similar dwellings’ test scores +2m3/h/m2 at 50 Pa. This type of testing does not reveal the exact air tightness of each residence and is therefore not advisable. Moreover, the penalty implemented on untested buildings makes the required air permeability rate difficult to attain.

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

Business owners and home owners in Benhilton have been helped by AF Acoustics air tightness testing. We come highly recommended by our clients because of the following guarantees.

Great service and expertise

Our experience in serving diverse customers in Benhilton is proof of our ability to satisfy your requirements no matter the size and type of building, or your circumstance. We’ll work with you to carry out our tests and consultations at times that are convenient to you, delivering an exceptional quality, convenient service. Our personnel will use their expertise to provide lasting solutions. Contact AF Acoustics in Benhilton –the right team for your building.

Registered member of the Air Tightness Testing & Measurement Association (ATTMA)

We are registered members of the ATTMA, a professional association dedicated to promoting technical excellence in air tightness testing and air leakage measurement applications. This means our expertise and quality of services are recognised by the leading air tightness testing body in the UK.

When to Call Us to Test Your Building

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

Next-day Turnaround on Test Certificate Where Possible

In order to satisfy our clients, AF Acoustics strives to provide test results and certificates on the next day.

Competitive Pricing

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

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

We Conduct Tests for All Types of Buildings in Benhilton

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. 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 requires that buildings know their air permeability rates by taking the air leakage test. Each building tested must achieve a maximum air permeability rate of 10m3/h/m2. In order to comply with the carbon emission target, it may be necessary to achieve a lower air permeability rate. The required air permeability rate for each building can be found on the design-stage SAP assessment or SBEM for that building. Excessive air leakage causes discomfort due to heat reduction and carbon dioxide discharge. It also creates convective loops within a building’s internal structure, leading to energy loss. Exfiltration/infiltration of air is caused by 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. 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 Benhilton. For your commercial building, air tightness testing will ensure your staff and clients are in a comfortable environment. Heating and cooling expenses are also reduced and the environment is more productive.

Part L Test

Since Approved Document L was reviewed in 2006, building regulations have demanded that new and rehabilitated constructions conduct air tightness test. Air tightness is referred to as air permeability or leakage rate. Air leaks through gaps and spaces in the building fabric such as service penetrations, walls and roof junctions. Sometimes, this is not obvious to occupants. The Building Regulations (Part L) demand that a selected group of different kinds of residential constructions and all non-domestic buildings greater than 500m2 perform air leakage tests. 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 leakage affects the building’s energy performance and is required to meet Building Regulations Part L and measure up to the standard for low carbon buildings.

What Is Part F Test?

We can complete all your Part F and Part L testing requirements. With our organisation, you receive:

  • Expert fan flow rate testing
  • Experienced air pressure testing
  • Professionals who provide Energy Performance Certificate, water and SAP calculations.

Approved Document F of the Building Regulations demands that all mechanical extract fans in newly completed constructions undergo a flow rate test. Evidence of this test must be passed to the Building Control Body (BCB) as part of their sign-off procedure. There are three alternative methods which can be followed to test, record and report the testing of extractor fans. AF Acoustics test process is the third method. It uses a vane anemometer and is called the minimum benchmark method.


Forms of Air Pressure Testing Services We Provide

Here are the descriptions of the ways air permeability can be tested: A single blower door fan is the instrument used for the first level to examine single buildings and smaller non-dwellings from 1m3 to 4000m3. Second Level – Testing is done for building 4000m3 and higher, typically simple and complex dwellings. High rise and phased handover buildings are not part of this test. Level Three: At this level, tests for the air pressure of high rise (LCHR) buildings and phased handover/zonal buildings.

Air Tightness Testing of Houses and Flats to Meet Approved Document L1

The measurement of air emitted by a building is tested to determine air permeability rating. 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. In order to comply with the carbon emission target, it is necessary to achieve a lower air permeability rate. You can find the required air permeability rate of your building in its 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.

Commercial Building Testing as Required by Approved Document L2A

The measurement of air emitted by a building is tested to ascertain air permeability rating. The result is expressed as a quantity in the form of air pressure (m3 per hour) per square metre of building fabric. Air tightness testing is required by Building Regulations. Each building tested must achieve a maximum air permeability rate of 10m3/h/m2. In order to comply with the SAP assessment, it may be necessary to achieve a lower air permeability rate. The design-stage SAP or SBEM assessment of a construction records its required air permeability rate. Uncontrolled air leakage can cause several problems. They are: infiltration of cold air, discomfort, reduction in heat, and higher CO2 emission rate.

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. When there is a fire, the auto opening vents play an important part in expelling smoke in multi-storey buildings. An air tight shaft creates sufficient pressure difference and ensures that the fans and vents perform properly to draw out smoke from a dwelling and save its occupants. AF Acoustics aims for the air permeability requirements of the automatic opening vent producers, so that their product can perform optimally. An air pressure test is conducted using a fan installed in the shaft. The intended openings of the shaft (i.e. extract point and openings for ventilation grilles on each floor) are sealed off for the test so that the integrity of the shaft itself can be determined. The test takes place in advance of the automatic-opening ventilation equipment being installed and commissioned.

We Offer 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 are able to test extraction rates. A building must have an optimal ventilation system to dispel humidity from bathrooms, kitchens and other rooms and extract odours and pollutants. We can also help you meet the Building Regulations targets. 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.

Air Tightness Test and Building Preparation Method

Air tightness test determines the level of air permeability in a building. The greater the air tightness of a building, the more comfortable the occupants are and the higher its energy performance.

It is difficult to notice unwanted openings in a building envelope. They might be blocked by the internal finishes. The most acceptable approach to show that a building fabric is impermeable is to identify leakage paths within it.

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 advise that all buildings undergo air pressure testing as there is a penalty for those that don’t.

What You Need to Do Before Undertaking the Test

Send the drawings of your dwelling (plans and elevations) and its target air permeability requirements to our test engineers. This is to have the needed information for the building and to know the size of the building envelope before coming to the site. Air tightness testing lasts for 30 to 60 minutes and wind speed is not more than 6m/s. 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.

  • Seal and turn off all ventilation, smoke vents and mechanical ventilation systems
  • Close the windows and open internal doors
  • Fill drainage traps
  • Switch off range stoves/cookers 24 hours before the test

Building Envelope Measurement

We undertake the building envelope calculations before we arrive on the site. 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.

Envelope Area Air Permeability

Air permeability, according to Approved Document L1A (2010), has to do with “air leakage rate per hour per square metre of envelope area at the test reference pressure differential of 50 pascals (50n/m2)”. The building’s envelope area has to do with the total area of all the floors, walls, and ceilings bordering the internal environment, including those below external ground level. These include shared walls, floors and ceilings in storey buildings. Internal dimensions are used to measure the envelope area.

Air Change Rate

The air change rate is important in designing a ventilation system, however, it is hardly a part of the actual design. To calculate ventilation rates for domestic buildings, the area and number of people living in the building are considered.

Evaluating a Cold Roof Envelope Area

This is essential to determine if the roof area is the same as the ground floor area. A cold roof has its insulation at the ceiling level, with space between the insulation and 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 boundary or barrier containing the overall internal ‘conditioned space’ separating it from the external environment (or non-conditioned spaces and adjacent buildings), and this is located on the warm side of the insulation.

Building Preparation

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

Site Test Process

Examine the wind speed, barometric pressure and temperature. Place the fan on an aperture within the building envelope. Ensure all the testing equipment is ready. Record the air volume flow through the fan (this equals the air leaking through the building envelope). Increase the speed of the fan slowly till it gets to 55-60Pa. Record how the air pressure differs at each fan speed.

Calculating Air Leakage

Our air leakage measurement involves picking out the gaps where air leakage takes place, recording the test information, sending results to customers in a technical report and advise clients on repair methods in the case of a test failure. Air Tightness Testing and Compliance

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 A functional ventilation system Reduced chance of mould and rot, as moisture is less likely to become trapped Fewer draughts, causing more comfort From a single dwelling to the largest commercial development, we offer stress-free compliance measurements to Part L Building Regulations and Building Standards. Not only do we provide services that meet building regulation targets, when you employ our services, you’ll save money and spend less in the long run. We test for air permeability, provide consultancy services and support services and review the designs of all buildings, whether domestic or commercial, large or small.


Good & Best Practice Methods

All new buildings, residential or commercial, must be air tight, according to Approved Document Part L1A of Building Regulations (2010). The regulation is focused on the conservation of fuel and power usage. Part L1A states that any new building must undergo an air pressure test, according to present regulations.

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

Certain technical standards are to be employed during air pressure test in the UK, as specified by ATTMA, building regulations and other documents. BS EN 13829:2001 and ISO 9972:2015 are clarified by the technical standards. The technical standards provide rules that ensure testing organisations get the same results from the same kind of tests and are based on BS EN 13829 “Thermal Performance of Buildings. Determination of air permeability of buildings. Fan pressurisation method” and ISO 9972:2015, “Thermal performance of buildings – Determination of permeability of buildings – Fan pressurization method”.

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

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. 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. A development with only two dwellings may not undergo a test if a suggested value of 15m3/h/m2 is stipulated in the DER/TER measurements. Your SAP assessor will be able to confirm if this is the case for your dwelling. The method for testing required by the building regulations is stated in ATTMA TSL1 (for dwellings) and ATTMA TSL2 (for non-dwellings). Non-Dwellings and residential buildings are required to test for air leakage. Buildings with a floor area of less than 500 m2 might not have to take the test. Where air tightness testing is not done, an assumed air permeability rate of 15 m3/h/m2 is used.

Building Regulations Part L (England And Wales)

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

Air 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.
  • Second Level – Testing is done in buildings with 4000m3 and higher. Large high rise and phased handover buildings are excluded from the test except a level three tester is in charge.
  • Level Three: Testing for the air pressure of high rise (LCHR) buildings, phased handover/zonal buildings and other complex buildings is carried out by level three experts.

Air Pressure Test

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 will be produced in accordance with company’s procedures, the relevant standards and the requirements of all relevant governing bodies.

Results of the Test

AF Acoustics will ensure the test result is written in accordance with the test standard requirements, identify any deviations from the relevant standards within the report and check air tightness against target value. We will ensure the report correctly identifies the tester, customer, building and its address. If a building fails the test, we provide remedial suggestions before a retest is carried out.

Resources Air Tightness Checklist – Dwelling

Before our test engineers arrive at the site, please adhere to what is written below and send the required air tightness target of your dwelling that is in the design to us.

Air 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

Temporarily cover the following;

  • Trickle Vents: Close them.
  • MVHR Terminal/Extract Fans: Switch off and seal temporarily.
  • Air Bricks and Chimney Flues: Cover temporarily.
  • Cooker Hoods: Seal off from the inside or outside.

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.