Air tightness testing determines the quantity of air coming out of cracks in a building. It is also known as air permeability testing or air leakage testing. Since Approved Document L was reviewed in 2006, air tightness testing has become an essential part of building regulations for newly completed and rehabilitated buildings.
Revisions were made to building regulations to address air leakages – a process where air escapes through any opening in the building, affecting its energy efficiency. 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. As a certified air leakage testing company in Hoddesdon, we are ready to provide testing services whenever you want. You can also call or email us for any of these services:
Because we are ATTMA members, any air tightness certificate we issue shows that the construction has met building regulation standards. We don’t just provide air tightness testing. We describe the process thoroughly, give expert advice on areas that could be problematic during testing, and suggest improvements based on the air permeability rating of the building. We deliver professional value for money service to the highest standards.
Air tightness testing is carried out to determine the volume of air escaping from holes in a 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. 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. 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 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 leads to heat reduction. When the weather is cold and windy, unwanted air seeps into a building through the holes and cracks in its fabric, causing heat loss and discomfort. It doesn’t stop there. Warm, damp air within the building escapes the gaps in its envelope. The water vapour in the moist air condenses on the inner wall surface holes. After a while, it is absorbed into building materials and diffuses, causing potential structural problems. Wet wooden framing or sheathing can rot and break down, diminishing its strength.
The building becomes structurally damaged as time goes on.
Air leakage can also cause these problems:
Successfully managing the movement of air into and outside the building will limit the damaging effects of moisture. An adequately installed air barrier reduces air leakage and condensation of water vapour on inner wall layers. Correct ventilation, whether passive or active, ensures fresh air circulates through the building, eliminating water vapour, moist odour and polluting substances.
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 contribute to global warming and CO2 emissions, since fossil fuels are used to create heat. Reducing air leakage reduces heat loss, which in turn reduces the amount of energy a heating system uses. Poor degrees of ventilation and high levels of uncontrolled air leakage encourage mould growth and excessive moisture. This could potentially cause medical issues. A great option would be to build tight and ventilate right. High levels of air leakage can lead to moisture ingress into the building fabric, resulting in expensive repair costs and potential health problems due to mould.
It is best practice to conduct at least two air tightness testing procedures, one early in the build and another at the end. Newly completed constructions’ energy ratings can be influenced by the test results, as they are used in SAP and SBEM calculations. For big residential developments, the test is not required for each house. A group of diverse buildings are picked for the test. With selective testing, you get a penalty of +2m3/h/m2. Houses that have a target score of 5m3/h/m2 must get a lower score of 3.
If your building has not been pressure tested, its assessed air permeability would be the average score of buildings like yours in the area +2m3/h/m2 at 50 Pa. 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.
With AF Acoustics, homes and businesses in Hoddesdon have been getting quality air tightness testing. Our customers highly recommend us to other people due to the following benefits.
Having served many clients in Hoddesdon, we have the expertise to work on any type or size of building. Our qualified air tightness testing professionals will work around your schedule, so they fit into your project seamlessly, providing a quality service as conveniently as possible. Do you need trustworthy professionals who will provide great results in Hoddesdon? Contact AF Acoustics today.
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.
You can access our complete air tightness test in Hoddesdon at anytime. We have responsive scheduling options. Schedule for your air leakage testing at your comfort. We guarantee no delays or complications regarding scheduling.
AF Acoustics has professional speedy services to satisfy clients who want their test results immediately. We have a next day turnaround policy for our test certificates and endeavour to deliver in all situations.
Save money by paying lower rates at AF Acoustics. As a business with low overheads, we’re able to give you one of the best air leakages testing services in Hoddesdon at reduced costs.
We conduct air permeability tests on residential and commercial buildings of all sizes and types. After the test, an ATTMA certificate is given to you. 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.
Air tightness testing is recommended by Approved Document L1A and L2A. Although your building is required to have a rating result of 10m3/h/m2, the actual result might have to be lower than that due to carbon emission requirements. You can find the required air permeability rate of your building in its design-stage SAP assessment or SBEM. With air leakage comes heat loss, greater CO2 discharge, draughts, thermal bypassing and wind washing and poor 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. In Hoddesdon, 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. With air leakage tests, business areas are more comfortable for employees and customers. In addition, you get lower heating and cooling costs. A comfortable environment results in a higher productivity rate.
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 air-tightness of a building is known as its ‘air permeability’ 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 commercial buildings greater than 500m2 undergo air tightness testing and a selection of residential buildings in a development be tested. Part L has also set a maximum air permeability target rate of 10m3/h/m2, but a building usually needs lower levels. Air permeability is key in the following areas: i. A construction’s energy performance, ii. CO2 emission targets iii. Building Regulations Part L standards
We can provide you all that you need to serve all your Part L and Part 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.
Approved Document F of the Building Regulations requires that all mechanical extract fans in new dwellings be subjected to a flow rate test. 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. Using a vane anemometer, our testing procedure follows Method 3 – The minimum benchmark method.
Here are the descriptions of the ways air permeability can be tested: 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. Air tightness testing for dwellings more than 4000m3, except big phased handover/zonal and high rise (LCHR) constructions is done. Air tightness testing for phased, zonal handover and LCHR constructions is done.
The measurement of air emitted by a building is tested to determine air permeability rating. The result is written as m3 per hour per square metre of building. Air leakage testing is a requirement of Approved Document L1A. A lower air permeability rate might be needed due to carbon emission requirements. The required air permeability rate for a dwelling can be found on the design-stage SAP report for that dwelling. Too much air leakage leads to heat loss which can lead to draughts and higher energy bills.
The measurement of air emitted by a building is tested to ascertain air permeability rating. The test results are inscribed using m3 per hour per square metre. Document L2A of Building Regulations declares air leakage testing to be mandatory. The test results have a limit; they shouldn’t be higher than 10m3/h/m2. The SAP or SBEM assessment for all buildings reduces the air permeability rate target. To get your building’s required air permeability rate, check 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 provide smoke shaft tests to make sure it is air tight enough to let the automatic opening ventilation work optimally when it’s installed and commissioned. Smoke needs to be cleared out in the event of a fire. The automatic opening ventilation is a vital aspect of the fire strategy for high rise buildings. An air tight shaft creates sufficient pressure difference and ensures that the fans and vents perform properly to draw out smoke from a dwelling and save its occupants. AF Acoustics aims for the air permeability requirements of the automatic opening vent producers, so that their product can perform optimally. 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. Once the test is completed and successful, the automatic opening vents are installed.
With the legal requirement for buildings that have the right quantity of air pressure, adequate ventilation that is suitable, effective and of high quality has become crucial. We evaluate extraction rates. This has not only been made compulsory by Building Regulations; it also helps reduce humidity in rooms, bathrooms and kitchens and expel pollutants. Building Regulations Part F also requires that the air flow test of all extractor fans (such as kitchen and bathroom extract fans) in new buildings to be conducted and results given to Building Control before construction ends.
The measurement of air pressure in a building is known as an air tightness test. Improving the air tightness of a building not only enhances the comfort of the occupants, but can also increases the building’s energy efficiency.
Holes and spaces in a building’s fabric might be hidden by the internal building finishes, making them hard to find. The most acceptable approach to show that a building fabric is impermeable is to identify leakage paths within it.
With residential buildings in an area, new building regulations demand that a minimum of 20% be measured for air leakage. Consistent samples are determined by the quantity of the different types of houses present during the construction of the project. Buildings that don’t undergo the test are penalised. All dwellings in a development should be tested to ensure optimum air tightness.
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:
Before coming to the site, we get the measurement of the building’s envelope. The building envelope is the surface area of the thermal boundary of the building. The calculations, which are extracted from the drawings, are fed into our estimations when testing your building for air leaks.
Approved Document L1A Conservation of Fuel and Power in New Dwellings (2010) defines air permeability as “air leakage rate per hour per square metre of envelope area at the test reference pressure differential of 50 pascals (50n/m2)” and envelope area as “the total area of all floors, walls and ceilings bordering the internal volume that is the subject of the pressure test. This includes walls and floors below external ground level. Overall internal dimensions are used to calculate this envelope area and no subtractions are made for the area of the junctions of internal walls, floors and ceilings with exterior walls, floors and ceilings.”
Air change rates are often used as rules of thumb in ventilation design but they are seldom used as the actual basis of design or a calculation. The calculation of residential ventilation rates is dependent on the area of the homes and number of occupants.
Measuring if the roof area and ground floor area of a building are the same is vital. A cold roof has the insulation at the horizontal ceiling level and a large void or space between the insulation and the pitched roof rafters.
A warm roof is a roof system where the insulation is fixed along the rafters with an air barrier inside the insulation. The envelope area is the boundary between the internal environment and external environment (adjacent buildings), and can be found on the insulation’s warm part.
Measure the weather conditions. Check the temperature, barometric pressure and wind speed. Connect a fan to an opening, like the door, in the building fabric. Set up the testing gear. Note the air flow volume from the fan. This is the same as the air leakage from the building envelope. Slowly raise the fan speed from 20-25Pa to 55-60Pa. Record how the air pressure differs at each fan speed.
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 Leakage Testing and Compliance
When a building has the right kind of ventilation (mechanical, natural or a combination of both) and has a low permeability rate, the advantages to the occupants are numerous. Some of them are: Your heating expenses are less because heat doesn’t escape through a permeable building, and you won’t require appliances with more heating capability. A functional ventilation system Lower levels of mould due to less moisture collecting in gaps and cavities. You won’t experience much discomfort because there will be fewer draughts. From a single dwelling to the largest commercial development, we offer stress-free compliance measurements to Part L Building Regulations and Building Standards. Our services include: air pressure testing, support services, re-examining designs and consultancy for all buildings in Hoddesdon. We are cost effective and adhere to all building regulations.
Building Regulation Part L1A 2010 stipulates that all new buildings must have low air permeability. The regulation helps to reduce the use of fuel and power. Part L1A further makes it obligatory for new buildings to be tested for air permeability in line with existing building standards.
Certain technical standards are to be employed during air pressure test in the UK, as specified by ATTMA, building regulations and other documents. The technical standards ensure that all companies have similar testing procedures. They are:
If you are constructing a dwelling the Approved Document L1A states that you must perform an air pressure test. For developments of two or more dwellings, an air leakage test should be carried out on the three units of each dwelling type; or 50% of all instances of that dwelling type. Where there are only one or two new buildings, add an assumed value of 15m3/h/m2 to the DET/TER measurements; an air tightness test may not need to be carried out. An SAP assessor can decide which buildings can use the assumed value successfully. The method for testing required by the building regulations is stated in ATTMA TSL1 (for dwellings) and ATTMA TSL2 (for non-dwellings). Air leakage testing is required on all residential developments (this may be a sample of units) and certain Non-Dwellings. Buildings with a floor area of less than 500 m2 might not have to take the test. Where air tightness testing is not done, an assumed air permeability rate of 15 m3/h/m2 is used.
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.
Authorised companies, who test buildings of different types, sizes and complexities, give air tightness reports. The testing companies seal extraction fans. After the test has been completed, they record test findings and results in a report. The report will be produced in accordance with company’s procedures, the relevant standards and the requirements of all relevant governing bodies.
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. Where it’s needed, we will identify if your building passed or failed the test and suggest ways to repair the building envelope before a retest is done.
Send us your building design air permeability target and crosscheck the list below before we get to the site.
Air Permeability Pathway Checklist – Use this checklist to make sure you are ready for the test. Ask yourself, “Have I sealed any visible opening?” Check the following appliances.
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:
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:
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:
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.
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
Our team of experts can support you through the following
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:
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:
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:
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:
No. Air tightness testing applies to:
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:
AF Acoustics lead air tightness testing Specialist, Gerard is your first port of call for all air tightness questions enquiries and surveys.
