ATTMA Licensed Air Tightness Testing in Herefordshire

Air tightness testing, also called air leakage testing or air pressure testing, calculates the quantity of air escaping through openings in a building. Air tightness testing has been a compulsory part of the building regulations for new dwellings, renovations and commercial projects since the revision of Document L in 2006.

The energy performance of a building can be affected by air leakage. To address this problem, alterations to building regulations have been made. Our certificates are registered with the Air Tightness Testing and Measurement Association (ATTMA), an organisation that guarantees technical excellence in all air leakage measurement methods. Located in Herefordshire, our company is a committed and accredited air permeability testing service provider; we provide air testing services. We also provide Part F mechanical extract fan flow rate testing, assessments and consultancy services.

As registered members of the ATTMA, our air tightness certificates are accepted as proof of building regulations sign-off. If you want specialist air pressure testing services in Herefordshire, AF Acoustics’ tightness testing services will

  • Describe the process to you,
  • Highlight possible problem areas that might occur during testing,
  • Conduct the air tightness test, and
  • Give advice on improvements based on the outcome of the test.

Our goal is always value for money and customer satisfaction. We are professionals and our services are of the highest quality.

Our Guarantee

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

Air Tightness Testing – What It Means

Air tightness testing is a 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. Draughts are uncontrolled ventilation. Using air tightness testing, the total air lost can be estimated. An excessive amount of uncontrolled air loss results in heat reduction, making the residents uncomfortable. The government aims to lessen the quantity of air flowing from newly built buildings. Therefore, regulations have been put in place to reduce uncontrolled ventilation from the building envelope, sustaining the right temperature conditions without using so much fuel. With air tightness testing, you can determine whether or not air is leaking from a building’s envelope, the build quality and energy efficiency of new developments. The introduction of tougher regulations has led to the construction of high-quality buildings. Building designs employ air tightness procedures from the early part of construction, creating a building that has adequate air tightness built into its design. When the building fabric is properly constructed to reduce air loss, the building is economical, and energy efficient.

Air Leakage Explained

Air leakage occurs when air escapes through holes and gaps in a building. When the circulation of air is properly monitored and bridled, ventilation has occurred. Another name for air leakage is infiltration. It may cause uncontrolled influx of air during frosty and windy weather. This reduces the temperature of the building, making the occupants uncomfortable. 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. 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

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

Over time, any of these conditions can cause structural damage.
The inhabitants become uncomfortable because of chilly homes, heating expenses increase and more CO2 is emitted due to the additional heat required.

The best way to reduce the harmful effect of moisture is to efficiently control how air moves into and out of the building. An adequately installed air barrier reduces air leakage and condensation of water vapour on inner wall layers. To get rid of pollutants, water vapour and moisture odour, the building must be well ventilated.


Why Must We Do an Air Tightness Test?

Air tightness is an integral element of energy efficiency. It is part of government’s plan to overcome climate change through advancements in the energy performance of buildings. Fossil fuel is burnt to heat up a building. This leads to a discharge of carbon dioxide which increases global warming. The best way to reduce the quantity of fossil fuel burnt is by stopping air leakage which reduces heat loss. 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. The best advice is to “Construct tightly, ventilate properly”. 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 results of the test can affect a building’s energy ratings because they play a part in SBEM and SAP calculations. Large residential areas do not need each building to be tested. Instead, different types of dwellings are tested. 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.

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. This type of testing does not reveal the exact air tightness of each residence and is therefore not advisable. Moreover, the penalty implemented on untested buildings makes the required air permeability rate difficult to attain.

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

AF Acoustics air tightness testing professionalism has helped many homes and business owners in Herefordshire. Our clients highly recommend us for the following reasons.

Service and knowledge

Due to years of experience in conducting air tightness testing in different kinds of buildings in Herefordshire, we have the skills to meet your needs no matter the type or size of your 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 Herefordshire –the right team for your building.

Air Tightness Testing and Measurement Association (ATTMA) Registered

We are registered members of the Air Tightness and Measurement Association (ATTMA). ATTMA encourages proper air leakage applications and promotes quality air tightness screening, and has recognised our impeccable professional services.

Responsive scheduling

We want to provide detailed air permeability testing in Herefordshire for you whenever you need it. Simply fix a convenient time for your building’s air permeability test. We offer responsive scheduling. We won’t make you wait or make the process complicated.

Next-day Turnaround for Certificates

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

Affordable Fees

At AF Acoustics, we offer the most competitive prices in Herefordshire 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 Permeability Testing for Different Kinds of Commercial and Domestic Dwellings in Herefordshire

We can test any building in Herefordshire for air leakages irrespective of its size, complex nature or type. Our tests are conducted by highly qualified professionals and we issue ATTMA certificates. Air tightness test checks the extent of uncontrolled air moving through openings in the building envelope. The result is expressed as a quantity in the form of The test results are described as m3/h/m2 – (m3 per hour) per square metre. of building fabric.

Approved Document L1A and L2A demands that buildings take tests for air leaks. The design-stage SAP assessment or SBEM of a construction records its required air permeability rate. While the law requires the highest air permeability rate to be 10m3/h/m2, your building might have to get a lower rate to meet the carbon emissions target. 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. 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 Herefordshire. 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. This increases the company’s productivity and lowers heating and cooling expenses.

A Description of Part L Test

Since Approved Document L was reviewed in 2006, building regulations have demanded that new and rehabilitated constructions conduct air tightness test. Other names for air tightness are air permeability rate or leakage rate. Air leaks through gaps and spaces in the building fabric such as service penetrations, walls and roof junctions. Sometimes, this is not obvious to occupants. It is compulsory for all commercial buildings with a gross area greater than 500m2 and a representative selection of domestic buildings to undergo air pressure test, as stipulated by Part L of the Building Regulations. Part L has also set a maximum air permeability target rate of 10m3/h/m2, but a building usually needs lower levels. You can exceed the CO2 discharge and Building Regulations target and raise your building’s energy performance by testing for air leakage.

Part F Test

All your Part L and Part F testing requirements can be met by us. We deliver quality air permeability and extract fan flow rate testing, and also recommend skilled experts who will handle your water calculations, SAP calculations and Energy Performance Certificates.
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. Examining, documenting and submitting reports of extract fans’ test can be done using three methods. Use method 3 – the minimum benchmark method, which tests extractor fans with vane anemometers. This is our testing procedure.


Forms of Air Pressure Testing Services We Provide

There are several levels of air leakage testing based on the kind, size and multifaceted aspects of a dwelling. Here they are: Level One: Testing for the air pressure of single buildings and smaller non-dwellings of 4000m3 gross envelope volume and below, a single blower door fan is used. 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. The third level tests big and complex zonal and phased buildings and complex high rise buildings.

Testing of Air Permeability of Residences and Apartments, in Accordance with Document L1 Stipulations

Air tightness testing determines the extent of air leaking out a building’s envelope. The test results are inscribed as m3/h/m2 – (m3 per hour) per square metre. Air tightness testing is required for new builds. In order to comply with the carbon emission target, it is necessary to achieve a lower air permeability rate. The design-stage SAP assessment SBEM of a construction records its required air permeability rate. Air leakage leads to heat loss, increased energy bills, greater CO2 emissions, and an uncomfortable atmosphere for inhabitants due to draughts.

Commercial Building Testing as Required by Approved Document L2A

An air leakage test is a test to determine the level of uncontrolled air flow through gaps or cracks in the fabric of a building. The result is written as m3/h/m2 – (m3 per hour) per square metre of building envelope. Air leakage testing is a requirement of Approved Document L2A. 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. Too much air leakage leads to heat loss (and consequently, higher CO2 emissions) and draught.

Air Leakage Test of Smoke Shafts for Auto Vents

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. When there is a fire, the auto opening vents play an important part in expelling smoke in multi-storey buildings. An air tight shaft creates sufficient pressure difference and ensures that the fans and vents perform properly to draw out smoke from a dwelling and save its occupants. AF Acoustics aims for the air permeability requirements of the automatic opening vent producers, so that their product can perform optimally. The shaft is tested for air permeability by using a fan that is fixed inside it. The openings for ventilation grilles and extract points on each floor are closed so that the state of the shaft itself is known. This test is conducted before the automatic opening ventilation is fixed and commissioned.

Air Flow Measurement of Domestic Ventilation (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. Extract fans are tested by us. It is important to ensure the ventilation strategy is working effectively. This helps to remove pollutants from the air and control excess humidity, particularly in rooms such as bathrooms and kitchens. Part F 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

An air tightness test measures the extent of air leakage in a building. When air leakage is reduced in a building, the occupants will not experience discomfort and the energy performance will increase.

External claddings and the internal building finishes might obscure a gap in the building fabric. This makes it hard to notice and can results to potential air leakage. To ensure that the air tightness of a building is optimal, gaps and spaces in the building have to be found and measured.

The new regulations stipulate that at least 20% of dwellings in a development be tested, but having a harmonious sample is dependent on the kind 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 You Need to Do Before Undertaking the Test

Our test engineers require the drawings (plans and elevations) and target air permeability requirements of your building before taking the test. An Air tightness test can be done in 30 – 60mins. Wind speed should not exceed 6m/s. Test engineers need to know the size of a building envelope and requirements before coming to the site. An air tight environment should be created in your building before the test to ensure optimal results. 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

Building Envelope Measurement

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.

Envelope Area Air Permeability

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 Change Rate

The air change rate is important in designing a ventilation system, however, it is hardly a part of the actual design. The calculation of residential ventilation rates is dependent on the area of the homes 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 has its insulation at the ceiling level, with space between the insulation and rafters.

Calculating the Envelope Area of a Warm Roof

In a warm roof, the main insulation is placed below the roof covering. In the warm part of the insulation, is the barrier between the conditioned and unconditioned space.

Preparing the Building

  • Shut all windows
  • Close the smoke vents
  • Shut and secure all inner doors
  • turn off the mechanical vents
  • Temporarily seal vents
  • Fill and block drainage traps

How the Test Is Done

Evaluate the weather (barometric pressure, wind speed and temperature) Place the fan on an aperture within the building envelope. Fix the instrument for testing. Record the air volume flow passing through the fan. Gradually increase the speed of the fan to a maximum of 55-60Pa. Record pressure differences across the building at each fan speed.

Air Leakage Measurement

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. Air Tightness Testing and Compliance

An airtight building has several positive impacts when combined with an appropriate ventilation system (whether natural, mechanical, or hybrid): Lower energy costs and need for heating appliances due to a higher level of heat retention. The ventilation system will operate optimally Your building will have less mould since moisture cannot escape into holes and cavities. Infiltration of air is reduced and the inhabitants are more comfortable. Our air leakage tests are conducted according to building regulations and targets, whether we’re testing a small dwelling or big commercial development. We provide air tightness testing, consultancy, design reviews and support services on all buildings, both dwellings and non-dwellings in Herefordshire. 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. Less fuel and power are consumed by buildings. The dwelling should be tested for air permeability in line with existing building standards, as stipulated by Approved Document Part L1A.

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. They explain in detail and provide guidelines for BS EN 13829:2001: “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

Building Regulation for England and Wales, Part L 2010

Undergoing an air tightness test is compulsory for your new building, according to Part L of Building Regulations. 50% or 3 units of each dwelling type should undergo an air leakage test in the case of an area with two or more dwellings. For developments where no more than two dwellings are constructed, it may be possible to avoid the need for any pressure testing by using an assumed value of 15m3/h/m2 within the DER/TER calculations. To find if your building falls into this category, contact your SAP assessor. The required process for testing buildings for air tightness has been declared in ATTMA TSL1 for occupied buildings and ATTMA TSL2 for unoccupied ones. Non-Dwellings and residential buildings are required to test for air leakage. 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

In January 2015, the ATTMA Scheme for Competent Air Tightness Testing Firms and Their Testers (The ATTMA Scheme) was launched. It is an industry competence scheme authorised by the government and specified in Technical Standard L1 & L2. The scheme echoes the conditions of the Minimum Technical Competence (MTC) and the National Occupation Standard (NOS) documents.

Testers can be divided into three types

  • Level One: Testing for the air pressure of single buildings and smaller non-dwellings of 4000m3 gross envelope area and below, is done with a single fan.
  • Second Level – Testing is done in buildings with 4000m3 and higher. Large high rise and phased handover buildings are excluded from the test except a level three tester is in charge.
  • 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

Authorised companies, who test buildings of different types, sizes and complexities, give air tightness reports. First, extraction fans are closed. Then, the details and results of the tests are written down in a report. This is done according to the testing organisation’s procedures and Building Regulation standards.

Results of the Test

Our test and subsequent results are conducted and written to meet standard requirements, highlight any deviation from the standards and crosscheck air pressure values against target values. Clients’ test reports contain their names, construction, address; the tester’s name is also included. We will state if your building has passed or failed the test and give advice on the actions you need to take if another test is needed.

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 Leakage Pathway Listing – You must ensure the following are properly sealed and don’t have any openings.

  • Windows
  • Metre boxes
  • Extract fans
  • Hoods of cookers
  • Bath panel
  • Hot water tank
  • Chimney
  • Tumble drier extracts
  • MVHR
  • Soil panel
  • Boilers
  • Radiators, fans and heaters
  • Skirting and coving
  • Drainage traps
  • Junction between floor and wall under kitchens and baths

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.