Month: November 2019

What is an Air Tightness Test?

What is an Air Tightness Test?

What is an Air Tightness Test?
Air leakage (also known as air permeability or air infiltration) is the air tightness of a dwelling through uncontrolled means such as cracks and gaps in the building envelope – walls, floors and ceilings.

Any ventilation system installed within a building is classified as a source of controlled air flow and is therefore not considered as air leakage and so these areas can be temporarily sealed during the air tightness test.

Air leakage is often felt as unwanted draughts, which will lower internal temperatures and may cause discomfort to building occupants especially in cold and windy weather.

Air tightness testing is a method of measuring and quantifying the air leakage of a building. Building Regulations Part L1A relates to dwellings and Building Regulations Part L2 refers to commercial buildings.

What is an Air Tightness Test?

Within the documents Air Tightness Testing is referred to as Pressure Testing and is the method by which developers measure the air tightness of their residential and commercial developments. Air testing shows how well properties will retain heat and in turn reduce carbon emissions, making them more efficient and cheaper to maintain.

An Energy Performance Certificate (EPC) is another compulsory requirement under Part L1A of the Building Regulations for all newly built residential and commercial units and these can only be issued when the air pressure testing results are available, to include within the SAP Assessment and thereafter the EPC.

How does Air Tightness Testing work?

Air Tightness tests are carried out by increasing the air pressure within the dwelling/building and then measuring the rate by which the pressure returns to normal. This is carried out using large fan/s inserted in the entrance doorway. The number of units you will have to test will depend on the number of unit types on your development. For most dwellings a single fan will be sufficient to pressurise the building; however, for larger commercial units a multi fan system will be required which is usually set up in blocks of 3 fans to each doorway.

What Air Permeability Figure do I need to achieve?

The Design Air Permeability for the dwelling/building will be determined initially by the lead consultant or SAP/SBEM assessor. The maximum design air permeability allowable is 10 m3/( @50Pa; however, this the more common figure of 5 m3/( @50Pa is often used. By aiming for a reduced Design Air Permeability and improving levels of air tightness it will serve to further reduce carbon emissions and make the Target Emission Rate (TER) easier to achieve. It may also mitigate the cost of more expensive carbon emission reduction strategies.

There are many common areas of air leakage; or air leakage paths within dwellings and commercial buildings, they are: Behind Bath Panels, Kitchen and Utility Units, Intermediate Floors, Behind Skirting Boards, Boxed in Pipes & Soil Stacks, Fireplaces, Poorly Installed Trickle Vents, Windows and Doors, Recess Lights & Loft Hatches.

Special attention should be shown to the above areas throughout the construction process.

Another interesting fact is that UK studies have demonstrated that a house/flat with robust air tightness credentials can often attain a higher sale price due to reduced energy costs over the lifetime of the building.

Building Regulations Part L and ATMMA TS1 both offer lots of useful information in regards  to Air Tightness Testing, such as which plots should be selected and what parts of the building can be temporally sealed etc.   If you would like more information on how to prepare your building to pass an air tightness test then please download our air tightness checklist.

Please Contact us now

If you would like more information on our air tightness testing service, then please visit our website at or contact us at: To have a chat about your project please call:  01525 303905

Improving your Air Test with Good Construction Detailing

Improving your Air Test with Good Construction Detailing

Improving your Air Test with Good Construction Detailing

Air Testing is the simplest and most popular method used in the construction industry to confirm compliance with Part L of the Building Regulations. The air test is simply a test of the building fabric integrity. Draughts and heat loss often occur wherever there is a hole or gap in the building envelope, resulting in the loss of heat/cooling which in turn will add to energy bills.

Since April 2006, air testing has been required to be tested for Air Permeability, in order to comply with Part L1 & L2 of the Building Regulations.  Since 2011 the air leakage target has reduced from 10m3/hr/m2 to 5m3/hr/m2. In the next 2 years it is expected that the target may be reduced to 3m3/hr/m2.

We provide a personal, helpful, efficient and cost effective air test service to our clients. Using the latest high power, portable door fans systems, we offer air testing to all building types, ranging from small rooms, flats & houses to office blocks & large distribution warehouses in accordance with the Building Regulations Part L1 & L2

Our air test fan systems are compact, discreet and fit simply into a personnel door. The system can easily be transported through areas of limited access or up to high level areas. Many contractors use us to undertake the testing in busy city centres or other tight access areas as we eliminate the site disruption caused by the larger trailer type air testing equipment.

In the event of a building failing an air test we then offer smoke testing – both hand-puffer for dwellings and large scale smoke testing for commercial buildings. This highlights the areas of air leakage through the building fabric. We can then undertake a full written and photographic survey as reference for your site management and relevant subcontractors. We will also offer FREE advice on the best method to seal any leaking areas. The main benefits of this are:

•             Air leakage paths are quickly identified in the event of a test failure

•             A full written air leakage report is forwarded so remedial works can start straight away

•             Building handover/practical completion and handover can be achieved more quickly

Construction Phase Consultancy

Air Pressure Testing has a practical ‘hands on’ approach during building construction and prefers to be involved as practically possible during this stage. We undertake periodic site visits to inspect the building envelope assembly as it is constructed and provide both written and photographic reports to enable any further works / remedial works deemed necessary to be accurately targeted. Site visits are generally to allow us to identify:

•             Insulation placement, continuity and effectiveness at thermal bridge junctions

•             Air barrier continuity within elements and at interfaces (particularly at sub-contract  package interfaces) 

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

a.            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.

b.            Ensure that the wall and floor damp-proof course/membrane forms an adequate airtight layer.

c.             With using timber frame construction, check that the sole plate is sealed to the foundation/floor-slab.

Internal Floors (Air Test risk factor 9)

a.            Using joist hangers can limit penetrations through the air barrier.

b.            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.

c.             Ensure timber floor sheets/boards are well fitted and sealed at their edges as well as at junctions with perimeter walls with mastic.

d.            Ensure the ceiling-to-wall joint has been sealed with mastic.

Eaves Level (Air Test risk factor 8)

a.            Ensure the airtightness layer between the wall and ceiling/roof is continuous ceiling below the roof space.

b.            Ensure there is a continuous air barrier over the whole ceiling area.

c.             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.

d.            Ensure all loft hatches are airtight and surrounds are sealed where they penetrate the air barrier.

External Doors & Windows (Air Test risk factor 7)

a.            Ensure you always specify good quality windows and doors.

b.            Always check that the wall-to-frame junction is properly sealed and continuous with mastic against the wall’s airtightness layer

c.             Ensure all windows and doors have an appropriate weather-seal between the opening unit and the frame – check for missing weather seals.

d.            All external doors should be fitted with draught excluders.

e.            Ensure the letterbox is fitted with a draught excluder.

Envelope Service penetrations (Air Test risk factor 10)

a.            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.

b.            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)

a.            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.

b.            Ensure all block-work is paint grade and painted were possible.

c.             The application of wet plastering, parging or the addition of fully-sealed dry lining will create a good air seal.

d.            Parging is an effective method of sealing around joists that penetrate the inner leaf of an external wall.

e.            Check that there is a good seal around all services that penetrate the masonry.

Plasterboard Dry lining (Air Test risk factor 10)

a.            Check the plasterboard is continuous (e.g. there are no large holes behind the kitchen units/bath). 

b.            Ensure that airtightness measures have been incorporated at all edges, particularly at the floor/ceiling junctions and around openings.

c.             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)

a.            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)

a.            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.

b.            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.

Remedial Air Sealing Solution

1.            Smoke Investigation with Air Testing Fans:

APT’s Air Sealing Team utilise smoke investigation to identify the air leakage paths and prioritise which can be sealed first to attain an air test pass.

2.            Remedial Air Sealing Works:

APT can carry out the air sealing works. Typically allow for a 2-4 man Remedial Air Sealing Team. Adequate access must be provided for all sealing works. We provide all air sealing Materials – Rates provided on Request.

3.            On-going Air Tightness Assessments:

Enables the APT Sealing Team to seal the building until the fans indicate that the air

test would pass – thereby minimising the remedial works and time on site.

4.            Final Air Test:

APT’s Air Test Technician carries out a final independent test for compliance.

Whether you need a full on-going air tightness design/consultancy service, or just a simple air test, Air Pressure Testing have the knowledge and experience to ensure your building passes first time.

If you are unsure of the air tightness services you require, please visit our website –, call us on 07775 623464 or e-mail and one of our Air Tightness Consultants will guide you through the process, ensuring that you receive the right level of advice at the right time.

Air Tightness Tests for London Project

Air Tightness Tests for London Project

How Many Air Tightness Tests do I need on my London Project?

The air tightness 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)
Air Tightness Tests for London Project

The dwelling(s) to be tested should be taken from the first completed batch of units of each dwelling type. For a dwelling to class as the same’ type’ as another it should consist of the following:

  • The same generic form, i.e. detached house, end of terraced, mid-terraced, semi-detached, ground floor flat, mid-floor flat, top floor flat, bungalow etc.
  • Have the same principle construction details
  • Have an envelope area that does not differ by more than 10%
  • Include the same number of storeys
  • Have the same Design Air Permeability (Air Pressure Test Target)
  • Have a similar adjacency to unheated spaces such as garages, unheated stairwells etc.
  • Have a similar number of apertures and penetrations, for example doors, windows etc.

To help builders and developers, there are two building standards that provide in depth information in regards to air tightness testing, they are Building Regulation Part L and ATTMA TS1 & ATTMA TS2

What is my Designed Air Permeability Target?  

Building Regulations Part L1A and L2A are specially aimed at new buildings and most are now required to have an air-tightness test. Part L1B and L2B cover work to existing buildings and do not generally have a requirement for air-tightness testing.

All new dwellings are required to have a SAP (Standard Assessment Procedure) calculation prior to building control approval. It is ultimately the SAP calculation that determines the air permeability target needed to be achieved and whether it is a requirement.

All new non-dwellings are required to have a SBEM (Simplified Building Energy Model) calculation prior to building control permeability targets and will require testing.

The design stage SAP and/or SBEM assessments provide the required ‘air permeability rate’ you need to achieve on the project. Clients often mistake the maximum permissible air permeability rate of 10m3/hr/m2 as their target; however it’s the ‘designed air permeability rate’ which you need to adhere to, which is usually much lower than this at around 3m3/hr/m2 to 5m3/hr/m2. If your project is in London, the requirements are often more stringent. Most air tightness tests in London need to achieve 3m3/hr/m2.

We are here to help you with your Air Tightness Test in London

If you are unsure how many London air tightness 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.

APT Sound Testing can assist you through the process and help you determine the specific air tightness testing requirements for your project. If you require more information please visit our website at

Different Types of Sound Testing

Different Types of Sound Testing

Different Types of Sound Testing
Sound Insulation Testing needs to be carried out between pairs of rooms separated by party walls or floors. In most cases the rooms to be sound tested will be the two main habitable rooms – living rooms and bedrooms. The sound testing procedure involves setting up a noise source in a room on one side of the party wall or floor and measuring the noise on both sides of the partition.

Sound Testing for Part E of Building Regulations has been a mandatory requirement since July 2003. All new build dwellings and conversions which were built after this date require 10% of each party wall/floor construction type to be tested.

There are two mains types of sound tests that need to be carried out prior to the building handover, they are:

Airborne Sound Tests
Airborne sound tests  are usually required between horizontally and vertically separated pairs of rooms. The sound tests are undertaken by using a sound source, amplifier and loudspeaker to generate a high noise level in one room (the source room). Noise measurements are then taken in both the source and receiver rooms using a prescribed number of source and microphone positions. The background levels in the receiver room are measured and the reverberation time in the receiver room is also measured. From the results, the airborne sound insulation (DnT,w + Ctr) is calculated and compared to the requirements of Approved Document E. For new build projects you are required to achieve 45dB for airborne sound testing through walls and floors and 62dB for Impact sound testing for floors. For refurbishment projects this changes to 43dB for airborne and 64dB for impact.

Impact Sound Tests
For vertically separated rooms, an Impact sound test may also be required. This sound test is undertaken using a “tapping machine”, (as above) which drops a series of weights onto the floor of the upper room. The noise level in the lower (receiver) room is measured for a prescribed number of source and microphone locations. The background levels in the receiver room are measured and the reverberation time in the receiver room is also measured. From the results, the impact sound insulation (L’nT,w) is calculated and compared to the requirements of Approved Document E.

Airborne Sound Testing of Building Facades
For the sound testing of external facades we place the loudspeaker outside  the  building  at a distance of 5m from the facade with  the  angle  of  sound incidence  equal  to  45° ± 5°  and  such  that  the  real  traffic  noise  impact  is simulated  the  best  possible  way.  The speaker and amplifier are used to generate a steady random noise signal via the loudspeaker source. The sound pressure levels are then measured at 2m in front of the facade plane and 1.5m above the ground.

All APT’s test engineers carry the latest Norsonic sound testing equipment, which are class one rating. All of our sound testing is completed to a strict quality controlled standard. We provide full ISO & UKAS complaint sound testing.

If you would like more information in regards to the Different Types of Sound Testing please contact us 01525 303905 or visit the APT Sound Testing website today.