Air Tightness Testing

APT Sound Testing provides air tightness testing throughout the United Kingdom. We undertake air testing on all types of projects from single dwelling to the largest commercial buildings. We are one of the few companies that are UKAS accredited to undertake both Air & Sound testing in compliance to Building Regulations and Standards. This means we can undertake Air, Sound and Vent Testing Packages during the same visit which provides our clients with cost savings and improved on site co-ordination. Unlike many companies we do not subcontract our works.

Air testing to achieve satisfactory levels of air tightness became a legal requirement in 2006 in England and Wales, under Building Regulations Part L and is becoming increasingly important to help produce greener buildings, via reducing carbon emissions due to the fact that energy is not being needlessly lost from residences via large air leakage paths etc. Building Regulation Part L defines ‘air leakage’ as the uncontrolled flow of air through gaps and cracks in the fabric of a building. The general public recognise it as draughts.

When you lose energy through the building fabric this is known as the building emission rate. New projects/developments must meet specific requirements for air testing and emission rates. The usual target for a standard dwelling is 5.0m3/hr/m2; however for commercial buildings the target rate is often much lower – around 3.0m3/hr/m2

Wherever air infiltration occurs, there is usually exfiltration somewhere else in the building. During the summer, infiltration can bring humid, outdoor air into buildings. In winter, exfiltration can result in moist indoor air moving into cold wall cavities and may result in condensation and mould and/or rot which could result in serious damage to the property.

We undertake air tightness consultancy and design reviews to help support our clients from the design stage of the project through to the precompletion air testing to achieve building control signoff. If you need to undertake your testing on Saturdays or Sundays, we offer an ‘out of hours testing’ service to help reduce the impact of testing during working hours.

We also offer substantial cost savings for combined air and sound testing packages. This is due to our multi skilled engineers being UKAS accredited to carry out the Air & Sound Testing, in fact most of our clients now use our ‘3 step’ precompletion package as it negates the need to employ multiple companies.

On site co-ordination is also improved, with both tests being undertaken on the same day in a planned methodical manner. We can also provide out of hours testing (if required) to help reduce the impact of testing during working hours. 

We provide a friendly expert advice for helping properties achieve required emission rates for air testing. Simply the use our contact form on this page, or call our offices, to chat about your specific air testing requirements with our knowledgeable team of air tightness consultants.

Maintaining a buildings continuous air tightness barrier/envelope greatly helps with the energy efficiency of the building. Air tightness testing is carried out in order to detect the amount of air loss from inside of a building, to the low pressure externally. Air escaping in and out of a leaky building envelope can lead to poor energy efficiency and cold draughts.

The air test checks the air tightness, permeability and air leakage that occurs from a buildings envelope. The air test checks amount of conditioned air that escapes or gets wasted through gaps or air leakage paths through the building fabric. If the building is more air tight, less energy will be being needlessly lost, thus lowering the carbon emissions of the building.

Air tightness testing also shows how efficient a building is at retaining conditioned air which will also put less straight on your mechanical and ventilation system. The energy required to produce the conditioned air – i.e. heating in winter or cooling in summering) is either increased or decreased based on how air-tight the building is. Air testing in the United Kingdom is governed by Part L of the Building Regulations, this split into two parts; for domestic properties Part L1A should be used and for commercial properties Part L2A should be referenced.

Failing to maintain adequate air tightness can lead to up to 50% of heat loss from within a building to the outside atmosphere. This negates the advantages of investing in energy efficiency measures such as extra insulation, high spec boilers or ground source heat pumps. Achieving an air tight building should be prioritised, otherwise your building will cost more to run and place extra load on your mechanical and electrical services; also, as if the building fails the air tightness test it may delay the handover of the building.

So to summarise, air tightness plays a significant role in the energy efficiency of buildings.

Because:

  • There is a proven link has been established between carbon emissions and global warming
  • The production of energy to heat buildings emits carbon
  • The built environment contributes about 50% of carbon emissions
  • Heated/conditioned air leaking from buildings requires the use of additional energy to maintain higher temperatures
  • Cooling/conditioned air leaking from buildings requires the use of additional energy to maintain lower temperatures
  • By limiting the leakage of heated/cooling conditioned air from buildings, it is possible to reduce energy consumption and costs.
  • The British government has made commitments to reduce carbon emissions through the European Energy Performance of Buildings Directive (EPBD) and the Kyoto Agreement.

If you require any further information on however to design an air tight building to pass its air tightness test, please contact us now. We provide a friendly expert advice for helping properties achieve required emission rates for air testing. Simply the use our contact form on this page, or call our offices, to chat about your specific air testing requirements with our knowledgeable team of air tightness consultants.

The air test can be carried out on a selection of dwellings/ building types – three units of each type or 50% of that type, whichever is fewer. It many cases it is necessary to test all plots, otherwise a 2m3/hr/m2 penalty must be applied to all the plots on the site, this means that you will need to 3m3/hr/m2 if your SAP report stipulated a designed air permeability rate of 5m3/hr/m2. So to summarise the following testing will usually be required:

  • All new dwellings (based on a sampling rate)
  • All commercial new buildings other than dwellings
  • ‘Large’ extensions to buildings other than dwellings (if the footprint of the building extension is 25% of the original buildings floor area)

If you are unsure how many air tests you require, please contact our friendly expert team for advice on helping properties achieve required emission rates for air testing. Simply the use our contact form on this page, or call our offices, to chat about your specific air testing requirements with our knowledgeable team of air tightness consultants.

This very much depends on the type of building that needs to be air tested. For dwellings, sufficient information is required to identify the different dwelling types. Usually we require floor plans and elevations as we as the designed air permeability rate which can be found within your SAP assessment. We also need to know if the doorway where our fan system will be temporarily installed is the correct size, i.e. 2100mm x 900mm.

For commercial buildings other than dwellings, we usually require the approximate envelope area, as this will determine which fan system will be required. This also affects the time on site and potentially a larger number of engineers to safely undertake the test. You can calculate this information from drawings, i.e. floor plans and elevations. We also need to know if the doorway where our fan system will be temporarily installed is the correct size, i.e. 2100mm x 900mm as in some circumstances this may require additional time on site, along with extra test engineers to construct a temporary bespoke door template.

We advise you to contact us as early as possible to ensure that your developments stand the best chance of passing air testing. However, the more complete a development is, the more likely it is to meet air testing requirements. When we send out our quotation we also forward a specific air leakage checklist to help our client prepare for the testing.

Meeting the following criteria will generally provide the best chance of passing testing:

a. The building envelope should be fully complete; this includes walls, floors and ceilings.
b. All doors and windows must be fully fitted and able to shut tightly against their seals.
c. All electric fittings must be installed and functional.
d. All mechanical fittings must be installed and functional.
e. Gaps within walls and floors must be sealed.
f. Bathrooms and kitchens must be fully fitted and all service penetrations sealed.
g. All mechanical ventilation turned off with grilles sealed.
h. All trickle vents to windows and doors must be sealed.
i. All fireplaces must be sealed.
j. Ensure water is present in soil pipes.
k. 240v power must be available on site.
l. Full access to all rooms is required.
m. No works must be taking place in test buildings.

Where access is possible air leakage paths should be sealed with expanding foam or other suitable sealant, whether in the wall, ground floor, intermediate floor or ceiling. Where large voids exist, you will first need to seal the penetration with mineral wool or some other backing material, this will be used to support the sealant otherwise the sealant will just collapse into the air leakage void.

We have a vast of amount of experience in identifying air leakage paths within dwellings and commercial units. To help our seal their buildings prior to the air testing we have written out a list for clients to reference during their air sealing works:

Typical air leakage paths in dwellings

1. Around various areas underneath and behind the kitchen units at the wall/floor junction and around service penetrations.
2. Around the underside of the SVP boxing to the corner of the kitchen units.
3. Around various areas underneath the utility units at the wall/floor junction and around service penetrations.
4. Around attic access door.
5. Around kitchen extracts, there is often a leak where the ductwork terminates through the building envelope.
6. Around boiler cupboard, there is often a leak where the ductwork terminates through the building envelope.
7. Around the wall/floor junctions on the ground floor due to unsealed skirting boards.
8. Around ground floor door and patio door thresholds due to doors not closing properly or unsealed perimeters.
9. Around window boards which are often unsealed.
10. Around window frames which are often unsealed.
11. Around the internal door to garage as this is part of the air seal line.
12. Around internal sliding door as the air often get into the wall ceiling void via the wall housing.
13. Around recessed ceiling lights where they are not installed properly or do not have air tight socks installed to the top of the light.
14. Around each side of the internal door thresholds which are often unsealed.
15. Around the staircases through the sides of the risers and around the bottom of the balustrading on the stairs and to landing.
16. Around the back of the toilets next to the service boxing which are often unsealed.
17. Around the underside of the wall mounted toilets which are often unsealed.
18. Around the pipes to the underside of the sinks which are often unsealed.
19. Around the base of the shower units which are often unsealed and or missing the plastic filler facia.
20. Around service penetrations through the walls and floors behind the bath and shower units.
21. Around various service penetrations with the in boiler cupboard.
22. Around the radiators pipes that terminate through the walls and floors.
23. Around the ceiling attic doors to the eaves and ceiling.
24. Around the internal upstand finishes around the Velux light units.
25. Air tightness membrane ripped or damaged at eaves junction.

Typical air leakage paths in commercial buildings – usually the similar to the dwellings checklist along with the following areas)

1. Around service penetrations behind the toilets IPS panels.
2. Around various areas within service risers.
3. Around various service penetrations into the plant room.
4. Around the internal upstand finishes around the roof lights units.
5. Around un-plastered masonry.
6. Around air conditioning plenums in walls and ceilings.
7. Around the eaves area at the wall/roof junction.

We provide friendly expert advice for helping properties achieve required emission rates for air testing. Simply the use our contact form on this page, or call our offices, to chat about your specific air testing requirements with our knowledgeable team of air tightness consultants.

In our experience, service penetrations are known to be one of the main routes for air leakage. Special care should be shown to sealing all service penetrations; however one of the main problems is they are often located in difficult to reach areas i.e. through the walls behind the kitchen cupboards and in bathrooms to the rear of toilets etc.

Where access is possible air leakage paths should be sealed with expanding foam or other suitable sealant, whether in the wall, ground floor, intermediate floor or ceiling. Where large voids exist, you will first need to seal the penetration with mineral wool or some other backing material, this will be used to support the sealant otherwise the sealant will just collapse into the air leakage void.

Excessive air leakage paths are often due to poor sequencing of construction work. One such example is the late addition of mechanical and electrical pipework which should have been installed earlier in the project.

Unfortunately once newly formed penetrations are made to the in building envelope; few operatives want to take ownership the resealing of the areas, as they may be in difficult to reach areas or the potential for dame to other finishes so they are left.

It is very important to seal all visible and hidden service penetrations to the following areas:

Service Penetrations

a. Service penetration’s around boilers pipes.
b. Service penetration’s around under floor heating.
c. Service penetrations in the kitchen and utility room.
d. Service penetrations in the toilets, bathroom and en-suite.
e. Pipework penetrations behind the radiators.
f. Service penetrations in the bathrooms and en-suite.
g. Around electrical fuse box.
h. Around extract fans.

General Air Leakage Paths

a. Gaps between skirting board and floor on each floor level.
b. Behind kitchen units.
c. Behind Utility Cupboards
d. Around poorly fitted trickle vents.
e. Around Patio doors.
f. Gaps around the stairs.
g. Around loft hatch.
h. Gaps around the bath panel and the shower tray.

We provide friendly expert advice for helping properties achieve the required emission rates for air testing. Simply use our contact form on this page, or call our offices, to chat about your specific air testing requirements with our knowledgeable team of air tightness consultants.

When we send out our air testing quotations, we also send across our informative air tightness checklist to help our client prepare for the testing. If each item is on the checklist is actioned then the air test should pass first time.

Our checklist lets our clients know about the following potential air leakage paths:

1. Dry-Lining (dot & dab) walls

Ensure that the external walls are completed and fully sealed prior to constructing internal stud partitions over them. The gap at the bottom of the plasterboard should be sealed to prevent air loss behind the board and into ceiling/roof spaces. Alternatively the gap between the bottom of skirting boards and the floor can be sealed. Avoid/minimise service outlets such as sockets, data outlets etc. in the dry lining of external walls as they are rarely well sealed.

2. Blockwork

Standard block-work is not impermeable paint grade block are better in most instances. The block density and standard of mortar joints have a significant impact on the overall permeability of the construction. Full mortar joints are preferable. Painting block-work reduces the permeability and two coats of emulsion can make a significant improvement. All gaps between block work and intermediate floors, roof members, windows/doors, steel columns, etc. should be sealed.

3. Timber Frame/Metal Studding

Ensure that the external walls are completed and fully sealed prior to springing internal stud partitions from them. Avoid/minimise service outlets such as sockets, data outlets etc. in the dry lining of external walls as they are rarely well sealed. Like the dot and dab walls, the gap at the bottom of the plasterboard should be sealed to prevent air loss behind the board and into ceiling/roof spaces.

4. Cast In Concrete Slab

This type of floor usually provides the best type of airtight seal, since the concrete fills any voids, both horizontally and vertically.

5. Pre-cast Hollow Concrete Floor Planks

The hollow core of this type of floor can allow air to track horizontally and end up outside the airtight layer of a cavity wall. The problems are made worse with drainage and service penetrations, which if poorly sealed allows air to enter the hollow core and escape. Care should be taken to ensure all penetrations are sealed properly. it is also prudent to seal the ends of the concrete planks.

6. Beam and Block Floors

This type of floor construction can lead to similar problems to those described for the pre cast planks above.

7. Timber Floors

Any penetrations passing through the top of the floor layer or the underside layer of (e.g. radiator pipes, waste pipes, boiler flues) need to be sealed where they pass through the timber/plasterboard layer.

8. Plasterboard & Lay in Grid Ceilings

Where roof/ceiling voids exist, lay in type false/suspended ceilings do not form an airtight barrier layer. Plasterboard type ceilings – if plastered and the edges sealed are significantly better than other types of lay in ceilings.

9. Doors & Windows

Door and window frames need to be sealed to the internal air tight barrier and not just sealed to the external façade. Window sills are often an area which performs particularly poorly and should be fitted after the cavity has been sealed using an appropriate cavity closer. For Windows & doors, refer to BS EN 12207 Windows & Doors Air Permeability Classification & BS EN 6375 – Use class 4 or better 3m3/(h.m2)@ 100Pa. Lift shafts have a permanent vent to outside at the head of the shaft and should be fitted with effective doors seals at each landing. Any floor or ceiling voids adjacent to the shaft should also be adequately sealed to prevent leakage.

10. Mechanical & Electrical Systems

The airtight barrier generally steps inside the building to include plant rooms as part of the external space. The plant room partition walls and sometimes service riser walls therefore require careful sealing around all mechanical and electrical service penetrations. Avoid using conventional fire stopping materials to form the airtight barrier, as these are seldom suitable. Particular care is needed to fill voids inside the electrical service trunking.

11. Sanitary Services

Careful consideration should be given to sealing the underside of all wall mounted toilets as the underside of the toilets are susceptible to air leakage where the SVP terminates through the wall. All drainage traps including floor gullies and air handling plant condensate traps should be filled with water prior to the air test.

If you need further advice on air sealing, please don’t hesitate to contact us now, we provide friendly expert advice for helping properties achieve the required emission rates for air testing. Simply use our contact form on this page, or call our offices, to chat about your specific air testing requirements with our knowledgeable team of air tightness consultants.

Clients are understandably worried about the impending air tightness testing on their developments. To try and help our clients better understand this area of works we have highlighted the most common questions we are asked along with our corresponding answers below:

What is air tightness?

Air tightness is related to the air permeability through the building fabric. This is not to be confused with the controlled flow of air into or out of the building through purpose built ventilators.

The importance of constructing air tight dwellings

The energy that we use to heat our homes and offices is primarily created by burning fossil fuels that produce carbon dioxide. By reducing air leakage of a building we also reduce the amount of energy required to maintain comfort levels and in turn reduce carbon dioxide emissions.

Why do we have to undertake air tightness testing in domestic properties?

By proving the air tightness testing of a building is now part of the Building Regulations Part L.

How many air tightness tests are required for a development?

On each development air tightness testing should be carried out on THREE units of each dwelling type or 50% of all the instances of that dwelling type, whichever is less; however a each block of flats should be treated as a separate development irrespective of the number of blocks on the site.

If I don’t undertake the air tightness testing on all the buildings on the development will it affect my SAP report results?

Air pressure testing can be carried out to a ‘sample’ of units; however, if you don’t undertake air testing to all the units the designed air leakage target is automatically lowered by 2m3/hr/m2, i.e. if air leakage rate shown on the SAP is 5m3/hr/m2 (a very common figure) then you will then need to get below 3m3/hr/m2 which is very difficult to attain. If fail any of the units – at the lower sample rate figure) then you are required to test all the units on the development.

Does my buildings extension require air tightness testing?

Where an extension is proposed to an existing building with a total useful floor area over 25% of the existing building the building should be air tested.

When should air tightness tests take place?

The air tightness testing should take place approx. 1-2 weeks before handover. The actual dwelling needs to be practically complete. To help you know if your building is ready to test we send out a pre-test check list.

How much does an air tightness test cost?

It depends on the location and the number of tests that are required on each site. Please contact us at info@aptsoundtesting.co.uk  to obtain a no obligation quote along with some friendly advice.

Will the air tightness test add value to my property?

Several UK studies have shown that improved and demonstrable property air tightness can yield savings of 15% to 30%. This should result in a higher sale price for the property because of on-going reduced energy costs and will be shown on your SAP & EPC assessments.

How long does a domestic air tightness test take?

It depends on a number of factors such as the size of the property, how many apertures need to be taped over. The duration of the actual air test should take no longer than 2 hours if the building has been adequately prepared.

How long does a commercial air tightness test take?

The duration of the commercial air test may take up to 4hrs, as the door panel is far bigger and more complex to set up in comparison to our ‘dwelling’ door panel and there is usually more building preparation required on the day of the test.

How quick can you send us the air test results?

If the property passes the air tightness test, a certificate should be issued within one week which should then be passed to the Building Control Body so it can be signed off.

What happens if I fail the air tightness testing?

Should the dwelling/building fail to meet the required standards of air permeability, then the weakness can be identified via smoke testing. The air leakage paths can then be recorded on a smoke survey report and given to the client to allow them to undertake targeted air sealing works. Once the remedial sealing works have been completed, a new air test can be undertaken to achieve a pass and building handover.

What are the common causes of air leakage in buildings?

The main areas of air leakage are normally through penetrations in the kitchens, utility rooms and bathrooms and toilets. The other main areas are usually around the wall/floor junctions and doors and windows. It is worth noting that the internal wall should always be used as the air seal line as the external wall is usually ventilated and is not designed to be air tight.

So how do you actually measure the tightness of my building?

The air tightness test is undertaken in-line with Part L and the ATTMA standard. The pressure differential is measured across the envelope of the building by means of the temporarily installation of a large fan inside a door panel. Thereafter, a range of static pressures and environmental readings are taken. The fan is switched on and the air pressure in the property is gradually increased or decreased and the differential pressure is recorded at each step. The total air flow required to achieve a pressure differential of 50 Pa is calculated and divided by the total building envelope area to provide the leakage rate in m3/h.m2@50Pa.

If you have any further question (that are not covered above) in regards to your air tightness test, then please contact us now. We provide friendly expert advice for helping properties achieve the required emission rates for air testing. Simply use our contact form on this page, or call our offices, to chat about your specific air testing requirements with our knowledgeable team of air tightness consultants.

First don’t panic, should the results of your air testing show unacceptable air leakage, we have many techniques available to find and record the air leakage paths, these include:

1. Air Tightness Design Review

We can undertake a design review of the proposed building to check that the air seal line has adequately designed and potential buildability issues have been taken into account.

2. Smoke Investigation with Building Under Pressurisation

Approx. one month before handover, we can carry out a smoke test whilst the building is being pressurised to check to identify air leakage paths and allow the areas to be sealed prior to the final precompletion test prior to handover. The smoke test reduces the chance of an air test failure at the end of the project.

3. Thermography Survey

This is performed using an infra-red camera to identify hot and cold spots on the surface of the building; this requires a temperature variation and is usually done in the evening.

4. Ongoing Site Survey Visits

We visit site to check that the contractors are building the envelope – or air seal line) properly to minimise the chance of an air test failure at the end of the project. Any potential problems identified during the works will be highlighted to the site team so that targeted remedial sealing works can be undertaken.

5. Final Air Test

We carry out the final precompletion test in accordance with Building Regulations Part L to achieve building control signoff and building handover.

In the vast majority of cases the first three methods are sufficient to identify the most significant air leakage paths; we can then record our finding via our smoke survey report which allows our clients to seal the air leakage paths. Thereafter the air test can be repeated to quantify the effect of addressing these areas, which should result in a test pass.

If your building has failed its air tightness test and you need further advice on how to pass, please call us on 01525 303905 or e-mail us at: info@aptsoundtesting.co.uk and we will guide you through the air tightness process, ensuring that you receive the right level of advice and service to pass your air testing.

Once of the main reasons of air tightness testing failure is due to contractors not knowing where the air seal line is. The air deal line is usually the inner envelope of the building; however if the building abuts an existing structure the air seal line may also encompass the existing internal wall. If you are unsure where the air seal line is, it’s always best to ask your architect or building control officer.

Here are the most common air seal lines within the building envelope along with the associated risk against each area:

Foundation/ground floor Initial works (Air Test risk factor 8)

  • Ensure that any penetrations through the air barrier (e.g. service pipes) have been dressed. Pre- formed collars sometimes referred to as ‘top hats’, which seal to the membrane and around the throat of the pipes are effective means of achieving a good airtightness seal.
  • Ensure that the wall and floor damp-proof course/membrane forms an adequate airtight layer.
  • With using timber frame construction, check that the sole plate is sealed to the foundation/floor-slab.

Internal Floors (Air Test risk factor 9)

  • Using joist hangers can limit penetrations through the air barrier.
  • If joists are to be supported by the wall, check that there is no air leakage into the cavity and the wall between the joists is fully filled/completed.
  • Ensure timber floor sheets/boards are well fitted and sealed at their edges as well as at junctions with perimeter walls with mastic.
  • Ensure the ceiling-to-wall joint has been sealed with mastic.

Eaves Level (Air Test risk factor 8)

  • Ensure the airtightness layer between the wall and ceiling/roof is continuous ceiling below the roof space.
  • Ensure there is a continuous air barrier over the whole ceiling area.
  • Ensure all service penetrations (ventilation ducts from extract fans and light fittings) have been properly sealed where they penetrate the air barrier as this is a major air leakage path.
  • Ensure all loft hatches are airtight and surrounds are sealed where they penetrate the air barrier.

External Doors & Windows (Air Test risk factor 7)

  • Ensure you always specify good quality windows and doors.
  • Always check that the wall-to-frame junction is properly sealed and continuous with mastic against the wall’s airtightness layer
  • Ensure all windows and doors have an appropriate weather-seal between the opening unit and the frame – check for missing weather seals.
  • All external doors should be fitted with draught excluders.
  • Ensure the letterbox is fitted with a draught excluder.

Envelope Service penetrations (Air Test risk factor 10)

  • Check for seals at service entry points (pipe and cable routes), e.g. around incoming water pipes, gas pipes, electrical cabling, as well as waste water pipes for sinks, baths, washing machines, dishwashers, etc. Seals should be provided internally and externally.
  • Where multiple services penetrate at the same point, there should be sufficient space to fully seal round each of them.

Brick/block masonry construction (Air Test risk factor 7)

  • Ensure the quality of construction as the work proceeds. Good mortar joints are required (i.e. no gaps around the blocks or bricks) on both internal and external faces – this also reduces sound transmission.
  • Ensure all block-work is paint grade and painted were possible.
  • The application of wet plastering, parging or the addition of fully-sealed dry lining will create a good air seal.
  • Applying a Parge coat is an effective method of sealing around joists that penetrate the inner leaf of an external wall.
  • Check that there is a good seal around all services that penetrate the masonry.

Plasterboard Dry lining (Air Test risk factor 10)

  • Check the plasterboard is continuous (e.g. there are no large holes behind the kitchen units/bath).
  • Ensure that airtightness measures have been incorporated at all edges, particularly at the floor/ceiling junctions and around openings.
  • Check the plasterboard is correctly detailed at joints, corners, reveals and window sills. Plasterboard should be mounted on ribbons of plaster or adhesive around all the edges (rather than dabs) to prevent air leaking through the porous block-work behind.

Sealed Membranes & Vapour barriers (Air Test risk factor 9)

  • Where the vapour barriers have been used as the air tight barrier, check that it is complete, that all joints have been sealed and it’s not damaged.

Timber frame construction (Air Test risk factor 8)

  • It’s usually easier to make timber frame dwelling airtight than other forms of construction. This is partly due to pre-fabricated construction and the use of the impermeable vapour barrier as the air barrier. The plasterboard layer can also become an air tight layer.
  • Where vapour barriers have been used special care will be needed to avoid it being torn. Any damage to the vapour barrier must be carefully repaired.

If you are unsure about the air seal line on your project, please contact now, we provide a friendly expert advice for helping properties achieve required emission rates for air testing. Simply the use our contact form on this page, or call our offices, to chat about your specific air testing requirements with our knowledgeable team of air tightness consultants.

The objective of the air test is to measure the volume of conditioned air escaping through the building envelope via uncontrolled ventilation at an induced pressure difference of 50 Pa. The calculation is expressed as m3/hr/m2.

The following basic steps are typical during an air test:

a. Check site preparation has been carried our as per our checklist – including temporary sealing) and advise if it has not.
b. Calculate the envelope area of the building under test, if not done previously.
c. Explain the testing process to relevant staff and sub-contractors working on or near the building.
d. Take environmental condition measurements – temperatures, barometric pressures prior to the test.
e. Install the temporary fan panel into a suitable doorway.
f. Install the fan/s into the temporary fan panel.
g. Connect monitoring equipment.
h. Check the static pressures.
i. Take multiple pressure difference readings and record fan flow rate(s) – usually 25-70Pa in 5Pa increments; allowing sufficient time for the pressure readings to stabilise.
j. Check the static pressure once the pressure readings have been taken.
k. Process the readings through appropriate software – check that readings fulfil the requirements of the standard of Building Regulations Part L.
l. If the building fails, attempt to identify/quantify air leakage/infiltration paths via smoke testing.
m. Disconnect measurement equipment.
n. Remove the fan from the temporary fan panel.
o. Remove the temporary fan panel.
p. Request the client sign APT site test book to ensure they are happy with the test.