ATTMA Licensed Air Tightness Testing in Friern-Barnet

Air tightness testing, otherwise called air pressure testing or air leakage testing, is the measurement of the outflow of air from a building’s fabric. It has been a mandatory part of the building regulations for new build and refurbishment projects since Approved Document L was revised in 2006.

Revisions were made to building regulations to address air leakages – a process where air escapes through any opening in the building, affecting its energy efficiency. We register our air tightness certificates with the Air Tightness Testing and Measurement Association (ATTMA), an organisation that encourages proper air leakage applications and promotes quality air tightness screening. We are dedicated and accredited air leakage testing service providers in Friern-Barnet and we are available to provide you with testing services whenever required. We also provide Part F mechanical extract fan flow rate testing, assessments and consultancy services.

Because we are ATTMA members, any air tightness certificate we issue shows that the construction has met building regulation standards. Not only do we test the air permeability of your building, we describe the procedure in a professional manner and advise you on problem areas discovered during the evaluation. Our services provide great value for money at high standards.

Our Guarantee

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

What is the Assessment of a Building’s Air Tightness?

Air tightness testing is a technique whereby a newly constructed building is evaluated and the quantity of air leaking through is measured. 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. Draughts are uncontrolled ventilation. Using air tightness testing, the total air lost can be estimated. Unrestrained air movement leads to heat reduction, making the inhabitants of the building 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 important in establishing air leakage from a building’s fabric, the energy efficiency of a new building and in identifying poor build quality within new developments. With the introduction of tougher regulations, building designs will often consider air tightness at the early stages of the construction process, ensuring attention to detail during construction to create an air-tight envelope. This can make a building more energy efficient since air leakage is under control. It will also be cost effective and of high quality.

Air Leakage, what Is It?

This occurs when openings in a building lead to excess air flow into and out of the building. When the circulation of air is properly monitored and bridled, ventilation has occurred. Another name for air leakage is infiltration. Because of the nature of air leakage, excessive air infiltration might occur in a building when the weather is windy and chilly. This results in loss of warmth and an unpleasant cold draughts. Testing for air leakage plays a primary role in determining the energy efficiency of a building. It is an important procedure that measures the air tightness level to ensure that the regulatory standards have been attained and the building’s energy calculations have been properly accomplished. 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?

Air leakage leads to heat reduction. During windy or cold weather, the infiltration of uncontrolled air through cracks in a building envelope occurs, leading to heat reduction. Movement of moist air into cavities in other parts of the building also occur. This process is called exfiltration. The warm air is filled with moisture, which hits the inner wall surface and condenses. Moisture is sucked into the building material, and this can lead to serious structural issues. The strength of the outer wooden covering is drastically reduced because it is wet.

These problems will eventually cause structural harm to the building.
The inhabitants become uncomfortable because of chilly homes, heating expenses increase and more CO2 is emitted due to the additional heat required.

The key to minimising the damage potential of moisture is effectively managing the flow 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. Passive or active ventilation is required to reduce water vapour, moisture odour and pollutants.


Why You Should Conduct an Air Tightness Test

Climate change caused by carbon dioxide emission is an environmental hazard that government is trying to curb. Energy performance and air tightness is a key part of this plan. Home heating involves burning up fossil fuel which produces carbon dioxide and aids global warming. The reduction of air leakage leads to lower heat loss and quantity of heat generated in a building. Individuals living in buildings with high levels of air leakage may have medical problems. Houses. Low ventilation and uncontrolled air leaks result in mould growth and moisture which can cause potential health issues. A great option would be to build tight and ventilate right. Air leakage causes infiltration of moisture into the building envelope, leading to health issues and high repair costs.

When Your Building Needs an Air Tightness Test

Best practice says that air tightness tests should be carried out early in construction and after the final phase. The results of the test can affect a building’s energy ratings because they play a part in SBEM and SAP calculations. Individual property is not tested in a large residential development. The test is done on different types of houses within the area. With selective testing there is a penalty of +2m3/h/m2; if the target score is 5 m3/h/m2 and selective testing was applied, the air tightness test would have to achieve a lower score of 3.

If your building has not been pressure tested, its assessed air permeability would be the average score of buildings like yours in the area +2m3/h/m2 at 50 Pa. It’s better to test each property because selective testing does not give a realistic picture of individual buildings. Besides, air permeability rates are difficult to achieve for untested buildings in such areas due to the +2m3/h/m2 penalty.

The reasons 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 Friern-Barnet. We come highly recommended by our clients because of the following guarantees.

Expert information and service

Our experience in serving diverse customers in Friern-Barnet is proof of our ability to satisfy your requirements no matter the size and type of building, or your circumstance. We have competent and accredited air testing professionals who provide a quality, convenient service. Our knowledgeable and dependable air testing experts will provide lasting solutions to your problem. Call AF Acoustics for your air tightness testing.

Registered by the Leading Air Tightness Body in UK

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.

Responsive scheduling

Our comprehensive air permeability testing in Friern-Barnet is available. Pick a time that is convenient for you in our responsive scheduling options. We won’t make you wait or make the process complicated.

Next-day Turnaround for Certificates

AF Acoustics has professional speedy services to satisfy clients who want their test results immediately. We have a next day turnaround policy for our test certificates and endeavour to deliver in all situations.

Fair Pricing

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

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

Get Air Leakages Test for Homes and Commercial buildings in Friern-Barnet

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 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.

Approved Document L1A and L2A demands that buildings take tests for air leaks. 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. 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. The warm air within a building rises, leading to the influx of cold air through gap, cracks and other openings in the building envelope. The increasing difference in air pressure results in infiltration and exfiltration of air. Air permeability testing is a legal requirement for constructions in Friern-Barnet. This way, they can have high energy performance, meet building regulations requirements and get signed off by building control. For your commercial building, air tightness testing will ensure your staff and clients are in a comfortable environment. In addition, you get lower heating and cooling costs. A comfortable environment results in a higher productivity rate.

The Part L Test

In 2006, Approved Document L was reviewed and building regulations for air permeability became tighter. The air tightness test is presently a requirement for new buildings and reconstructions. Air tightness can also be called air leakage or air permeability rate. Although not always seen, air leakage can occur through any gap, space or crack in a building’s fabric. 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 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.

Part F Test Explained

We will help you with all your Parts L and F requirements. In addition to conducting your air pressure test and extract fan flow rate testing, we can put you in contact with professionals who provide SAP calculations, Energy Performance Certificates, and water calculations.
According to Part F, it is compulsory for a flow rate test to be conducted on all mechanical extract fans of new buildings. Building Control Body (BCB) will see proof that the test has been conducted before signing off your building. You can test, document and report the test of your building’s extractor fans in three ways. 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

Air Tightness Testing has different tiers, depending on how complex a building is and its size. Find them below: 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 Two: Single and multifaceted buildings 4000m3 gross envelope volume and above are tested for air pressure. High rise (LCHR) buildings and phased handover/zonal buildings are excluded from this level. Level 3: Air Pressure Testing for LCHR buildings, phased and zonal handover buildings is carried out.

Approved Document L1 Air Pressure Testing of Houses

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. Part L1A of Building Regulations stipulates that such tests be conducted. Your building may need a lower rate to meet the CO2 discharge target. To get your building’s required air permeability rate, check its design-stage SAP assessment SBEM. Uncontrolled ventilation can cause several problems. They are: infiltration of cold air, reduction in heat, more CO2 emission and higher energy costs.

Commercial Building Testing as Required by Approved Document L2A

Air leakage testing is the measurement of uncontrolled ventilation from a building’s fabric. The result of the air leakage test is expressed as a quantity of air leakage (m3 per hour) per square metre of building envelope. Part L2A of Building Regulations has demanded that such tests be conducted. The test results have a limit; they shouldn’t be higher than 10m3/h/m2. A building will usually have to achieve a lower rate to meet the SAP or SBEM assessment. The air permeability target can be found in a building’s design-stage SAP or SBEM assessment. Excess air leakage causes heat loss, greater carbon dioxide discharge and influx of cold air.

We Offer Smoke Shaft Air Pressure Testing

We undertake smoke shaft integrity testing to confirm that the shaft is sufficiently air tight in order to allow the automatic opening ventilation to perform as required when it is fitted and commissioned. Smoke needs to be cleared out in the event of a fire. The automatic opening ventilation is a vital aspect of the fire strategy for high rise buildings. 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. We work towards air permeability targets set by the automatic-opening ventilation manufacturers that allow their equipment to operate effectively. An air pressure test is taken for the smoke shaft by installing a fan inside. Once the fan is fixed, the extract points and ventilation grilles on each storey are sealed to ensure that the shaft is in proper condition. This test is conducted before the automatic opening ventilation is fixed and commissioned.

Air Flow Measurement of Domestic Ventilation (extraction fan testing)

The requirement for air tight buildings that are properly insulated has brought about the need for ventilation systems that are adequately installed and function at an optimal level. We are able to test extraction rates. 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. 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.

Specific Test and Building Preparation Procedure

An air tightness test measures the extent of air leakage in a building. If the rate of air pressure is good, the energy performance of a building will be high and the inhabitants will be comfortable.

It is difficult to notice unwanted openings in a building envelope. They might be blocked by the internal finishes. The best solution to demonstrate a building’s air tightness level is to check for leakage paths in the building envelope.

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. There is a penalty for untested constructions. Therefore, we suggest air leakage tests for all buildings.

Pre-Test

Clients should send the drawings (plans and elevations) and air permeability requirements to our engineers. The test engineers would like to have the information needed for the test before coming to your development. Our air leakage test is done between 30 and 60 minutes, and the wind speed is a maximum of 6m/s. To 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)

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 measurement is obtained from the construction drawings, and put in our calculations to conduct the test.

Air Permeability from the Envelope Area

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

Air Change Rate

Air change rates are often used as rules of thumb in ventilation design but they are seldom used as the actual basis of design or a calculation. Residential ventilation rates are calculated based on area of the residence and number of occupants.

Measuring a Cold Roof Construction’s Envelope Area

It is important to make sure the roof area and ground floor area of a building are equal. A cold roof is a roof that has its insulation in the ceiling and there’s a huge space between the insulation and rafters.

Warm Roof Envelope Area Measurement

A warm roof is a roof system where the insulation is fixed along the rafters with an air barrier inside the insulation. The envelope area is the barrier between the conditioned space in the insulation and the unconditioned space outside.

Building readiness

To get the building ready, close and secure all internal doors, windows, Temporarily seal vents and smoke vents. Also fill drainage traps.

Process for Testing the building

Check all weather conditions such as temperature, wind speed and barometric pressure. Connect a fan to an opening, like the door, in the building fabric. Set up the equipment for air tightness testing. Calculate the air flow volume through the fan which equates to the air leakage. Increase the speed of the fan slowly till it gets to 55-60Pa. The pressure differences in the building at each fan speed should be calculated.

Evaluating Air Leakage

Our competent engineers note the points of air leakage, examine the test data and send test results to the customer in a technical report. If the test fails, we inform clients on what to do about it. Air Tightness Testing and Compliance

An airtight building has several positive impacts when combined with an appropriate ventilation system (whether natural, mechanical, or hybrid): Your heating expenses are less because heat doesn’t escape through a permeable building, and you won’t require appliances with more heating capability. Your ventilation system will operate in a better way Less mould will be trapped in the building fabric as a result of less moisture. Infiltration of air is reduced and the inhabitants are more comfortable. Be assured that you’ll get a test that meets all the regulations and standards no matter how big or small your building is. We provide air tightness testing, consultancy, design reviews and support services on all buildings, both dwellings and non-dwellings in Friern-Barnet. We also provide cost-effective, local service that complies with all relevant Building Standards.


Best Practice Procedures

Building Regulation Part L1A 2010 stipulates that all new buildings must have low air permeability. This regulation was put in place to conserve fuel and power. Part L1A further makes it obligatory for new buildings to be tested for air permeability in line with existing building standards.

Determining Air Leakage in buildings (Dwellings), According to Technical Standard L1

ATTMA has specified technical standards that must be adhered to while testing buildings in the UK, according to building regulations and other documents. 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

If you are constructing a dwelling the Approved Document L1A states that you must perform an air pressure test. Those exceptions only occur when there are two or more dwellings in a development. Three units of a dwelling type or 50% of all examples of that dwelling type should be tested. 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. An SAP assessor can decide which buildings can use the assumed value successfully. ATTMA TSL1 and ATTMA TSL2 prescribe methods for testing occupied and unoccupied buildings. Air leakage testing is compulsory for residential areas and certain Non-Dwellings. Non-dwellings where floor area is less than 500 m2 or has an assumed assessed air permeability rate of 15 m3/h/m2 in their calculations, may not have to undergo the air leakage test.

Building Regulations for England and Wales, Part L

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. The scheme echoes the conditions of the Minimum Technical Competence (MTC) and the National Occupation Standard (NOS) documents.

Air leakage testers have three levels

  • First Level – For buildings not more than 1m3-4000m3, typically single and smaller non-dwellings, a single fan is used to carry out air tightness testing.
  • Level 2: Testers can test all buildings except large, complex and or high-rise buildings and or phased handover or zonal buildings unless part of a team managed by a level 3 tester.
  • Level 3: These are air tightness experts who can cover large, complex and or high-rise buildings and or phased handover or zonal compartmentalisation.

Air Pressure Test

Air leakage test reports are given by authorised organisations that test different buildings. First, extraction fans are closed. Then, the details and results of the tests are written down in a report. The report will be produced in accordance with company’s procedures, the relevant standards and the requirements of all relevant governing bodies.

Air Tightness Test Results

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. Clients’ test reports contain their names, construction, address; the tester’s name is also included. If a building fails the test, we provide remedial suggestions before a retest is carried out.

Resources Air Tightness Checklist – Dwelling

Before we arrive on site, ensure you have sent us the air permeability target and been through the checklist below and the ones we have sent you. This will greatly facilitate the process.

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

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.