Air Tightness Testing, Certified by AF-Acoustics, in Spring-Grove

The measurement of air escaping from a building is called air tightness testing. It is also referred to as air permeability testing or air pressure testing. Air tightness testing became an integral part of building regulations for new buildings, commercial developments and revamped buildings in 2006 after Document L was reviewed.

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. 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. As a certified air leakage testing company in Spring-Grove, we are ready to provide testing services whenever you want. We also provide Part F mechanical extract fan flow rate testing, assessments and consultancy services.

We are registered members of the ATTMA. As a result, our air tightness certificates prove that the building requirements for your building have been met. We are professionals who take the time to explain the testing process, we are able to give informed advice on where problem areas may occur during testing, and how improvements can be made based on results of air pressure testing. AF Acoustics provides services that are cost effective and of high standard.

Our Guarantee

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

What is Air Tightness Testing?

Air tightness testing is a method of measuring the extent to which air is lost through leaks in the building fabric. Other names for air tightness testing are air leakage testing and air pressure testing. Air leakage should not be confused with ventilation. Also called draughts or infiltration, air leakage is unrestrained movement of air through holes in a building fabric, while ventilation is the restrained and planned movement of air. Air tightness testing is the recognised method used to measure total air lost through leaks in a building fabric. This is often referred to as uncontrolled ventilation (draughts). Unrestrained air movement leads to heat reduction, making the inhabitants of the building uncomfortable. Air leakage from buildings causes heat loss, more energy is then used to keep the building warm, this is a cause of excess CO2 emissions. This has resulted in regulations which are centred on decreasing air leaks from the building fabric, therefore lowering CO2 emissions. Air tightness testing is important in establishing air leakage from a building’s fabric, the energy efficiency of a new building and in identifying poor build quality within new developments. 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. A building that is air tight A building that is air tight is more economical and ensures less drafts ALS energy efficient.

What Is Air Leakage?

Air leakage is uncontrolled air movement in a building due to cracks. Air leakage is the uncontrolled movement of air into and out of a building through gaps and spaces in the building’s fabric. Also called infiltration, it differs from ventilation which is the regular, planned and restrained flow of air into a building. Once the atmosphere is windy, draughts infiltrate the building through holes in the fabric, leading to heat reduction and discomfort. Air leakage testing plays a significant role in the energy-saving efficacy of properties. With air tightness testing, you can be sure that the building has met the stipulated targets used for energy calculation and air tightness. 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.

What Is the Impact of Air Leakage?

Air leakage leads to heat reduction. During windy weather, cold air infiltrates a building through the openings in its fabric. This results in heat loss. It doesn’t stop there. Warm, damp air within the building escapes the gaps in its envelope. When moist air hits a cooler surface within a wall structure, water vapour in the air can condense and collect inside these spaces. Moisture can then be absorbed in building materials and cause serious defects. Wet wooden framing or sheathing can rot and break down, diminishing its strength.

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 most effective method of lessening the damage caused by moisture is to control the flow of air into and out of the building. The potential of vulnerable wall structures to absorb condensed moisture is reduced when air barriers are properly installed and uncontrolled air flow is reduced. Correct ventilation is important, whether it is passive or active, to remove water vapour, unwanted 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. Heating buildings involves burning fossil fuel which increases CO2 emissions and causes global warming. The reduction of air leakage leads to lower heat loss and quantity of heat generated in a building. 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. The best advice is to “Construct tightly, ventilate properly”. The result of uncontrollable air moving into the building fabric could be health problems and costly repairs.

Recommended Period for Air Tightness Test

Best practice dictates that you complete an air tightness test early in the build process, and then again after the construction process is completed; although not all builds have the first test phase. The test results are part of SBEM and SAP calculations, therefore they influence the total energy ratings of new buildings. 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.

Where the dwelling has not been pressure tested, the assessed air permeability is the average test result obtained from other dwellings of the same dwelling type on the development, increased by +2.0 m3/h/m2 at 50 Pa. Selective testing is not advisable, as it does not give a realistic picture of the air tightness of each individual building. A tested property might be a lot tighter than an untested property. Also, the penalty implemented on the untested houses make air permeability rates very difficult to achieve.

Why Choose AF Acoustics for Your Air Tightness Testing?

At AF Acoustics, our air tightness testing expertise has helped many home and business owners in Spring-Grove. Our clients highly recommend us for the following reasons.

Helpful service and information

Our experience in serving diverse customers in Spring-Grove 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 personnel will use their expertise to provide lasting solutions. Contact AF Acoustics in Spring-Grove –the right team for your building.

Registered Members of the Leading Air Tightness Body in the UK

We are registered with ATTMA, a professional body that focuses on high quality air tightness testing and air permeability applications. This means our services are endorsed by the leading air leakage testing body in the UK.

When to Call Us to Test Your Building

You can access our complete air tightness test in Spring-Grove at anytime. We offer responsive scheduling options. You can schedule for air tightness testing at your convenience. We won’t make you wait or make the process complicated.

Quick Turnaround on Test Certificates Where Possible

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

Affordable Prices

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

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 Spring-Grove

We can test any building in Spring-Grove for air leakages irrespective of its size, complex nature or type. Our tests are conducted by highly qualified professionals and we issue ATTMA certificates. You can find out how much uncontrolled ventilation your building has by testing it for air leakages. The results are registered as The test results are described as m3/h/m2 – (m3 per hour) per square metre of building.

Approved Document L1A and L2A requires that buildings know their air permeability rates by taking the air leakage test. A maximum air permeability rate of 10m3/h/m2 is required. However, a building has to achieve a lower rate to meet the carbon emission target. To get your building’s required air permeability rate, check its design-stage SAP assessment SBEM. Excess air leakage causes heat loss, greater carbon dioxide discharge and can make occupants uncomfortable due to the influx of cold air. It also causes wind washing and thermal bypassing, resulting in lower energy performance. Exfiltration/infiltration of air is caused by a stack effect. Due to the pressure difference inside and outside the building, rising warm air reduces the pressure in the base of the building and draws in air, whether through open doors, windows or other openings and leakage points. To get signed off by building control in Spring-Grove, all buildings are to undergo air tightness testing and measure up to the required energy efficiency standards. Clients and employees will be at ease in their surroundings. It will also help you reduce the cost of maintaining heating or cooling in your commercial building, making it more productive.

The Part L Test

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. Other names for air tightness are air permeability rate 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. Part L of the Building Regulations requires that all non-domestic buildings which have a gross floor area greater than 500m2, be subject to mandatory air permeability tests. For domestic dwellings, a sample of houses (in a development) must be tested. The maximum air permeability rating allowed is 10m3/h/m2, but your building might need a lower rating ts. Air tightness is important for meeting the Building Regulations Part L standards, exceeding requirements for low carbon buildings, and overall energy efficiency.

A Description of Part F Test

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.
Get the mechanical extract fans tested for flow rate. This is what Building Regulations Approved Document F requires. The Building Control Body (BCB) has to see the results of the test as part of its sign-off procedure. There are 3 available methods for examining, recording and reporting the testing of extract fans. AF Acoustics employs the minimum benchmark procedure (method 3), which involves using a vane anemometer.


What Kinds of Air Tightness Testing Services Do We Offer?

Here are the descriptions of the ways air permeability can be tested: Level 1: Air pressure testing for single dwellings and other smaller non-dwellings up to 4000 m³ gross envelope volume, typically tested with a single blower door fan. 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. Air tightness testing for phased, zonal handover and LCHR constructions is done.

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

Air leakage testing is the measurement of uncontrolled ventilation from a building’s fabric. The test results are inscribed as m3/h/m2 – (m3 per hour) per square metre. Part L1A of Building Regulations stipulates that such tests be conducted. A lower air permeability rate might be needed due to carbon emission requirements. The required rate can be found in a building’s 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.

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 result is written as m3/h/m2 – (m3 per hour) per square metre of building envelope. Document L2A of Building Regulations declares air leakage testing to be mandatory. Each building tested must achieve a maximum air permeability rate of 10m3/h/m2. Your building may need a lower air permeability rate to meet the SAP or SBEM assessment. You can find the required air permeability rate of your building in its design-stage SAP or SBEM assessment. An excessive amount of air leakage leads to greater energy expenses, heat reduction, carbon dioxide discharge and draughts.

We Offer Smoke Shaft Air Pressure Testing

We test the integrity of the smoke shaft to ensure the automatic opening ventilation is placed in the best condition. Automatic opening vents are crucial during fire emergencies in storey buildings, as they clear out smoke from the buildings. For the vents and fans to operate at the expected level, the smoke shaft must be air tight to create a difference in air pressure and give emergency services when needed. With the right air permeability rate, the vents can operate at their best. We aim for the air permeability rate set by the vent manufacturers. Fans are placed in the smoke shaft to conduct an air tightness test. The usual openings are closed off too so that the shaft’s integrity can be determined. 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 have the capacity 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. Part F states that all new constructions must have intermittent extractor fans whose air flow rates will be calculated and the results given to Building Control before the building work is finished.

Particular Test and Building Readiness Operation

Air tightness test determines the level of air permeability in a building. When air leakage is reduced in a building, the occupants will not experience discomfort and the energy performance will increase.

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 recommend that all dwellings be tested, as there is a penalty for developments that are not tested.

Pre-Test Requirements

Send the drawings of your dwelling (plans and elevations) and its target air permeability requirements to our test engineers. We would like to know the requirements and the building envelope’s size prior to testing. The tests take 30 – 60 minutes, and wind speed does not surpass 6m/s. An air tight environment should be created in your building before the test to ensure optimal results. Do the following:

  • Turning off all range stoves and cookers (if applicable)
  • Turning off mechanical vents
  • Shutting all windows and external doors
  • Sealing ventilation grids and smoke vents
  • Filling the drainage stops

Measuring the Building’s Envelope

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 building envelope calculations are taken from the drawings and used for our air tightness testing.

Air Barrier Envelope Area

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 Exchange Rate

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

Evaluating a Cold Roof Envelope Area

It is important to make sure the roof area and ground floor area of a building are equal. A cold roof is the kind of roof where the insulation is fixed in the ceiling joists with space between the insulation and roof rafters.

Warm Roof Envelope Area Measurement

In a warm roof, an air barrier is inside the insulation which runs on the pitched roof rafters. The envelope area is the barrier between the conditioned space in the insulation and the unconditioned space outside.

Building Preparation

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

Site Test Process

Examine the wind speed, barometric pressure and temperature. Connect a fan (or fans) to an aperture in the building envelope (e.g. door). Set up testing equipment. Calculate the air flow volume through the fan which equates to the air leakage. Slowly raise the fan speed from 20-25Pa to 55-60Pa. Record how the air pressure differs at each fan speed.

Measuring air leakage

We can determine where air leakage is occurring through our test procedure. Once the test has been completed, we crosscheck the data and send a report to you. If the test fails, we will advise you about corrective measures. Testing for Air Permeability and Following Part L Building Regulations

The positive effects of an air tight building with efficient ventilation (natural, mechanical or a combination) cannot be underestimated. Here they are: Reduced heating expenses because of lower heat loss, with less need for equipment that has high heating ability. Your ventilation system will operate in a better way Less mould will be trapped in the building fabric as a result of less moisture. Thermal comfort is enhanced because air infiltration is lower. From the smallest to biggest building or development, we adhere to Building Regulations Part L and Building Standards. Our services include: air pressure testing, support services, re-examining designs and consultancy for all buildings in Spring-Grove. We are cost effective and adhere to all building regulations.


Best Practice Processes

Building Regulation Part L1A 2010 stipulates that all new buildings must have low air permeability. The regulation is focused on the conservation of fuel and power usage. 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.

There are technical standards for air tightness test of buildings in the UK detailed by Air Tightness Test and Measurement Association (ATTMA). 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

Undergoing an air tightness test is compulsory for your new building, according to Part L of Building Regulations. 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. If there are no more than two new dwellings, using an assumed value of 15m3/h/m2 in the DET/TER calculations might exempt them from air tightness testing. Your SAP assessor will be able to confirm if this is the case for your dwelling. 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

ATTMA has a scheme for air leakage test organisations, which commenced in January 2015. The scheme was approved by the government and is stated in Technical Standard L1 and L2. The scheme echoes the conditions of the Minimum Technical Competence (MTC) and the National Occupation Standard (NOS) documents.

There are three levels of testers:

  • A single fan is the instrument used for the first level to examine single buildings and smaller non-dwellings from 1m3 to 4000m3.
  • The second level examines simple and complex buildings greater than 4000m3, with the exclusion of large zonal buildings and complex high-rise buildings unless a level three tester is in charge of the procedure.
  • The third level expert tests big and complex zonal and phased buildings and complex high-rise buildings.

Air Leakage Test Report

Accredited testing companies issue air pressure reports. Extraction fans will be sealed temporarily; the results of the test are recorded in a short report. The organisation makes sure the report meets the company and government’s requirements.

Outcome of Air Leak Test

We analyse our tests and results for any divergence from the standards required and check the air pressure rate against target rate. That way, our results are expressed in line with test standards. We will ensure the report correctly identifies the tester, customer, building and its 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

Please send your design air pressure figure to us and go through the list below before we arrive at your site.

Air Leakage Pathway Checklist – Check will be done for visible leaks in the following places:

  • Windows: Check the seal beneath the sills and around the frames.
  • Doors: Check the seal around all external door surrounds (especially French doors).
  • Drainage traps: Check if they are filled with water.
  • Skirting and coving: Check above and below all skirting and coving, sealing where necessary.
  • Metre Boxes: Check all external supplies are sealed appropriately.
  • Light Fittings: Check the seal around all light fittings and switches.
  • Radiators / Fans / Heaters: Check the seal around all pipes and wires.
  • Boilers: Check the seal around the boiler supply and flue.
  • Extractor Fans: Check around the edge of the extracts, only the front of the grill can be sealed.
  • Cooker Hoods: Check the seals around all penetrations.
  • Soil pipes: Check the seal around all soil pipes and sink waste pipes especially those boxed in or behind kitchen cabinets.
  • Bath Panels: Check if all pipes behind bath panels are sealed properly.
  • Hot water tank: Check the seal around all supply pipes.
  • MVHR: Check seal around all terminals.
  • Chimneys: Open fireplaces must be sealed prior to our arrival.
  • Tumble drier extracts: Check the seal around the extract.
  • Junction between floor and wall under kitchens and baths

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.