Air Tightness Testing, Certified by AF-Acoustics, in West-Kensington

Air tightness testing, also called air leakage testing or air pressure testing, calculates the quantity of air escaping through openings in a building. In 2006, Approved Document L was reviewed and building regulations for air permeability became more stringent. The test is presently a requirement for new buildings and reconstructions.

Air leakage occurs through any opening in the building envelope and can affect a building’s energy performance, this has been addressed by changes to the building regulations. AF Acoustics certificates are certified by Air Tightness Testing and Measurement Association (ATTMA). ATTMA is an association of specialists that concentrate on promoting the best air tightness measurements and air permeability testing techniques. Located in West-Kensington, our company is a committed and accredited air permeability testing service provider; we provide air testing services. 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.

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. 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

Air Tightness Testing – What It Means

Air tightness testing involves calculating the quantity of air which escapes through holes in the building fabric. It is sometimes referred to as air leakage testing or 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. Draughts are uncontrolled ventilation. Using air tightness testing, the total air lost can be estimated. When too much air leaks through a building’s fabric, heat loss occurs, making the occupants uncomfortable. Regulations now concentrate on minimising air leakage from the building envelope thereby reducing the amount of fuel burned for maintenance. This helps reduce carbon dioxide emissions. Calculating the emission of air from a building’s fabric, establishes the energy efficiency of the building. Building plans will often consider air tightness at the beginning stages of development so as to measure up to stricter building standards. A building that is air tight A building that is air tight is more economical and ensures less drafts ALS energy efficient.

What Air Leakage Is

Air leakage is where air enters and leaves a building uncontrollably through cracks and holes in the building fabric. When the circulation of air is properly monitored and bridled, ventilation has occurred. Another name for air leakage is infiltration. As air leakage is uncontrolled, too much air may enter the house during cold or windy weather, leading to excessive heat loss and uncomfortable 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 mandatory since 2006 for all new builds and non-dwellings with a floor area over 500m².

Air Leakage’s Resulting Outcomes

When air escapes uncontrollably from a building, heat reduction occurs. Once the atmosphere is cold and windy, unwanted chilly air infiltrates the building through gaps, leading to heat reduction. It doesn’t stop there. Warm, damp air within the building escapes the gaps in its envelope. 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. Wet wooden framing or sheathing can rot and break down, diminishing its strength.

Over the years, these problems can damage the building’s structure.
Other impacts include:

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

These effects can be mitigated by controlling the circulation of air into and out of the building. An adequately installed air barrier reduces air leakage and condensation of water vapour on inner wall layers. Passive or active ventilation is required to reduce water vapour, moisture odour and pollutants.


Why Should We Do an Air Tightness test?

Air tightness is an integral element of energy efficiency. It is part of government’s plan to overcome climate change through advancements in the energy performance of buildings. Heating buildings contribute to global warming and CO2 emissions, since fossil fuels are used to create heat. A reduction in air leakage lessens the heat needed to keep a building warm. Uncontrolled air leakage also results in health problems. Coupled with poor air circulation, it leads to the growth of mould and mildew. To “Construct tight, ventilate right” is the best practice. High degrees of air leaks cause huge problems such as expensive remedial work on the building and medical problems.

When Your Building Needs an Air Tightness Test

A building should ideally be air tightness tested early in the construction process and again at the end of the building project, although sometimes only the final check is carried out. The test results are part of SBEM and SAP calculations, therefore they influence the total energy ratings of new buildings. Large residential areas do not need each building to be tested. Instead, different types of dwellings are tested. This type of testing attracts a penalty of +2m3/h/m2, consequently, if the target result is 5m3/h/m2, a lower score of 3 would have to be attained.

If the building has not been tested for air tightness, assessed air permeability rate is the average result of similar buildings in the area +2m3/h/m2 at 50 Pa. Selective testing is not recommended because: i.It is quite tough to achieve the lower air permeability rate set for untested dwellings. ii.The proper air tightness rate for each building in the development cannot be attained, as only some underwent air tightness testing; a tested building might be much tighter than an untested one.

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

Business owners and home owners in West-Kensington have been helped by AF Acoustics air tightness testing. Our customers highly recommend us to other people due to the following benefits.

Helpful service and expert knowledge

In West-Kensington, we have served many clients. The experience garnered from our years of service will help us meet your specific needs no matter the size or type of property. 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 West-Kensington –the right team for your building.

Registered by the Leading Air Tightness Body in UK

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

When to Call Us to Test Your Building

We would like to give your building in West-Kensington a thorough air leakage test whenever it is needed. Simply fix a convenient time for your building’s air permeability test. We offer responsive scheduling. There won’t be delays or complications once you’ve fixed a time.

Next-day Turnaround for Certificates

Our customers are eager to get their test results. AF Acoustics, which provides reliable, competent services, strives to issue test certificates on the next day.

Affordable Prices

At AF Acoustics, we offer the most competitive prices in West-Kensington to ensure you have access to affordable air tightness testing when you need it. We keep the costs down, as we are a small business with low overheads. This allows us to be competitive with our pricing whilst guaranteeing a professional service.

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

Air Tightness Testing for Domestic & Commercial Buildings of All Types and Sizes in West-Kensington

Regardless of the size, type, or complexity of your domestic or commercial building in West-Kensington, we can provide you with air tightness testing, carried out by an experienced and professional air tightness tester and issue you a certified ATTMA certificate. Air permeability testing calculates how much air moves through spaces in your building’s fabric. The results are registered as The test results are described as m3/h/m2 – (m3 per hour) per square metre of building.

Air leakage testing is required by Approved Document L1A and L2A. 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. Too much air leakage leads to heat loss (and consequently, higher CO2 emissions) and discomfort. It can also create convective loops within a building; this is often referred to as thermal bypassing and wind washing. 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. In West-Kensington, the law demands that all new buildings be tested for air pressure before they can be approved and signed off by building control. This enables dwellings achieve energy efficiency standards. 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.

A Description of Part L Test

Air tightness testing has been a mandatory part of the Building Regulations for new build and refurbishment projects since Approved Document L was revised in 2006. 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. To adhere to Part L, make sure your building’s air permeability rate is not greater than 10m3/h/m2. 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.
New buildings should ensure that all mechanical extract fans are tested for flow rate, as stipulated by Part F of the Building Regulations. Building Control Body (BCB) will see proof that the test has been conducted before signing off your building. Extractor fans can be tested and recorded, and test reports submitted using 3 methods. AF Acoustics employs the minimum benchmark procedure (method 3), which involves using a vane anemometer.


The types of Air Tightness Testing Services We Offer

Air Tightness Testing has different tiers, depending on how complex a building is and its size. Find them below: A single blower door fan is used for air tightness testing for single buildings and smaller non-dwellings not more than 4000m3. Air tightness testing for dwellings more than 4000m3, except big phased handover/zonal and high rise (LCHR) constructions is done. The third level tests big and complex zonal and phased buildings and complex high rise buildings.

Approved Document L1 Air Pressure Testing of Houses

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 (mm3 per hour) per square metre of building envelope. Document L1A of Building Regulations declares air leakage testing to be mandatory. In order to comply with the carbon emission target, it is necessary to achieve a lower air permeability rate. 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.

Testing of Air Permeability of Commercial Dwellings, in Accordance with Document L2 Stipulations

Air pressure testing involves the calculation of air escaping through the openings in a building. The air leakage test result is written as m3/h/m2 – (m3 per hour) per square metre of building. Part L2A of Building Regulations has demanded that such tests be conducted. The maximum air permeability rate for a dwelling tested is 10m3/h/m2. A building will usually have to achieve a lower 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. Too much air leakage leads to heat loss (and consequently, higher CO2 emissions) and draught.

Air Leakage Test of Smoke Shafts for Auto Vents

To ensure that the auto opening vent will perform optimally when fitted and commissioned, we test the smoke shaft to verify its air tightness. 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. For it to expel smoke from a building and keep the occupants safe during emergencies, the shaft must be air tight enough to create substantial pressure difference. 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. An air pressure test is taken for the smoke shaft by installing a fan inside. Then the openings are sealed off in all its parts so that the shaft can be thoroughly examined. The test takes place in advance of the automatic-opening ventilation equipment being installed and commissioned.

Air Flow Measurement of Domestic Ventilation (extraction fan testing)

The requirement to build more highly insulated and air tight buildings means that it is increasingly more important to ensure buildings are not only adequately ventilated but the ventilation system is suitable and commissioned correctly to ensure its effective operation. Extract fans are tested by us. 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 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.

Air Tightness Test and Building Preparation Method

Air tightness tests calculate the level of air leakage a building has and if it is excessive. Improving the air tightness of a building not only enhances the comfort of the occupants, but can also increases the building’s energy efficiency.

It is difficult to notice unwanted openings in a building envelope. They might be blocked by the internal finishes. The only satisfactory way to show that a building fabric is airtight is to detect and measure leakage paths within the building fabric.

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. Buildings that don’t undergo the test are penalised. All dwellings in a development should be tested to ensure optimum air tightness.

What Should You Do Before Testing Your Building?

Our test engineers would like to see the drawings (plans and elevations) and design air permeability requirements of your building before taking the test. 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 prepare the site for the test, do the following:

  • 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

Measuring the Building’s Envelope

We undertake building envelope measurements before getting to the dwelling for the test. The building envelope, is the physical barrier between the exterior and interior of a construction. The calculations, which are extracted from the drawings, are fed into our estimations when testing your building for air leaks.

Air Permeability from the Envelope Area

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

Air Exchange Rate

Although hardly used as a major deciding factor for calculation or design, air exchange rate is vital in ventilation design. To calculate ventilation rates for domestic buildings, the area and number of people living in the building are considered.

Calculating the Envelope Area of a Cold Roof

It is important to make sure the roof area and ground floor area of a building are equal. A cold roof is a roof that has the thermal insulation put in the ceiling with wide space between the insulation and pitched roof rafters.

Calculating the Envelope Area of a Warm Roof

In a warm roof, an air barrier is inside the insulation which runs on the pitched roof rafters. The envelope area, found at the insulation’s warm side, is the separator between the conditioned internal aspect and the unconditioned.

Building readiness

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

Site Test Process

Check weather conditions (wind speed, temperature, barometric pressure); Fix a fan to an aperture, usually the door, in the building. Set up the equipment for air tightness testing. Record the air volume flow passing through the fan. Gradually increase the fan speed from 20-25 Pa to a maximum of 55-60Pa. Note the difference in air pressure in several parts of the building at each fan speed.

Evaluating 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

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. The ventilation system will operate optimally Less mould will be trapped in the building fabric as a result of less moisture. Fewer draughts and enhanced comfort Our clients can expect a stress-free conformity to Part L Building Regulations standards, whether they have a single building or a large commercial building. We render cost-effective services that include air leakage tests, design reappraisal, consultancy and support services for dwellings and non-dwellings in West-Kensington.


Good and Best Practice Styles

Building Regulation Part L1A 2010 stipulates that all new buildings must have low air permeability. Less fuel and power are consumed by buildings. Part L1A further makes it obligatory for new buildings to be tested for air permeability in line with existing building standards.

Air Tightness Testing of Dwellings That Meet Technical Standard L1L1

ATTMA has specified technical standards that must be adhered to while testing buildings in the UK, according to building regulations and other documents. The technical standards ensure that all companies have similar testing procedures. They are:

  • “Thermal Performance of Buildings. Determination of air permeability of buildings. Fan pressurisation method” BS EN 13829:2001, and
  • “Thermal performance of buildings – Determination of permeability of buildings – Fan pressurization method” ISO 9972:2015
Call us today for a quote on 020 3372 4430
Or you can email us at info@af-acoustics.com

Building Regulation for England and Wales, Part L 2010

If you are constructing a dwelling the Approved Document L1A states that you must perform an air pressure test. Where there are two or more new buildings in an area, conduct a test on 50% of all examples of a kind of dwelling or 3 units of a dwelling kind. If the development has one or two dwellings only, an air tightness test might not be taken if the DET/TER calculations assume a value of 15m3/h/m2. Find out from your SAP assessor if this is applicable to you. The required process for testing buildings for air tightness has been declared in ATTMA TSL1 for occupied buildings and ATTMA TSL2 for unoccupied ones. Air leakage testing is required on all residential developments (this may be a sample of units) 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 Regulation Requirements 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.

Testers can be divided into three types

  • A single fan is the instrument used for the first level to examine single buildings and smaller non-dwellings from 1m3 to 4000m3.
  • Air tightness testing is done in all dwellings but big phased handover/zonal and high rise (LCHR) constructions are not included except a level three tester is the head of the team.
  • Third Level – These experts carry out air tightness testing in large and complex high rise and phased handover buildings.

Report on Test for Air Permeability

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 is in line with the company’s testing process set by government regulations and all relevant governing bodies.

Air Tightness Test Results

AF Acoustics guarantees the test outcome is written in line with standard requirements; it picks out any deviations from the significant benchmarks inside the report and checks air permeability against target values. We make sure our report has the name of the building, customer, address and tester. Where applicable, we will identify pass or failure of your building and provide recommendations for any remedial action or improvement to the building if any further testing is required.

Resources Air Tightness Checklist – Building

Send us your building design air permeability target and crosscheck the list below before we get to the site.

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

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

We Provide Temporary Sealing – the following should be temporarily sealed during the test;

  • Trickle Vents: Should be closed.
  • Extractor Fans / MVHR terminals: All extracts should be temporarily sealed (Please ensure these are off before sealing).
  • Cooker Hoods: Should be sealed from the outside or inside.
  • Chimney Flues and Air Bricks: Should be temporarily sealed.

Air Tightness Testing FAQ’s

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

The common leakage sites are:

All pipe works within the kitchen and bathrooms

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

Our team of experts can support you through the following

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

No. Air tightness testing applies to:

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

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

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

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

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

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

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

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Gerard Finn

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