Building Air tightness Testing
Airtightness testing is the recognised method used to measure the total air lost through leaks in the building fabric. This is often referred to as uncontrolled ventilation (draughts).
The test is important in establishing the energy efficiency of a new building and can identify poor build quality within new developments. With the introduction of tougher regulations, building designs will often consider air tightness early in the construction process to ensure it complies.
What is air leakage and why is it important?
Significant uncontrolled air leakage can result in:
The new Building Regulations Part L require all newly constructed dwellings (residential & Commercial) properties to achieve a minimum figure of Air Permeability to be no worse than 8.0 m3(h.m2) at 50.0pa, Designers and SAP & SBEM design calculations may target an even lower figure that is required under the specifications for the project to meet the DER & TER, DFEE & TFEE figures.
A typical target for the new build home is 5.0 m3(h.m2) at 50.0pa or is 1.0 m3(h.m2) at 4pa (Pulse equipment), a figure below 5.0 m3(h.m2) would generally then require mechanical supply and extract systems (MVHR or packaged Air Handling plant) to be installed.
We at B&MC carry out the following testing criteria’s and are accredited with Elmhurst Energy.
During 2025 there will be a change and update to RDSAP (The domestic dwelling software that is used to establish a domestic dwelling Energy Performance Rating).
What this will mean is that currently when a dwelling is aged during the survey e.g. 1960s built it will, by default apply a Air Permeability figure of 25 m3/hr m-2 – “buildings built to Building Regulations pre 1995 (pre 1994 in Scotland)“ can be overridden with a valid air testing certificate, so if a property has been modernised e.g. double glazed windows, suspended floors sealed and any cracks/joints etc sealed to the fabric this could mean a figure that is a vast improvement on the above and will reduce the EPC rating which will be beneficial to both Home owners, but in particularly landlords with a portfolio of buildings.
During a test we would normally undertake a pre test to establish the initial air permeability figure on a new built property( applies to existing as well), once established the owner or builder can seal up any areas that are highlighted.
Once completed we carry out a final test and record the figures and lodge the reports and certification.
Below is a link to a PDF of facts for Buidling Air Testing, please feel free to download.
Airtightness testing is the recognised method used to measure the total air lost through leaks in the building fabric. This is often referred to as uncontrolled ventilation (draughts).
The test is important in establishing the energy efficiency of a new building and can identify poor build quality within new developments. With the introduction of tougher regulations, building designs will often consider air tightness early in the construction process to ensure it complies.
What is air leakage and why is it important?
- Air Leakage occurs when outside air enters, or conditioned air leaves, a building uncontrollably through cracks and openings.
- Air leakage will typically take place through:
- Joints, gaps and cracks in the construction, Gaps created where the structure penetrates the outer skin of the building.
- Gaps where services enter the building.
- Porous construction material such as bricks, blocks, mortar joints.
Significant uncontrolled air leakage can result in:
- Unwanted heat loss.
- Discomfort for occupants (draughts and cold homes/offices)
- Increased heating bills (to counter the cold).
- Greater energy use, running costs and CO2 emissions (as result of additional heating required).
The new Building Regulations Part L require all newly constructed dwellings (residential & Commercial) properties to achieve a minimum figure of Air Permeability to be no worse than 8.0 m3(h.m2) at 50.0pa, Designers and SAP & SBEM design calculations may target an even lower figure that is required under the specifications for the project to meet the DER & TER, DFEE & TFEE figures.
A typical target for the new build home is 5.0 m3(h.m2) at 50.0pa or is 1.0 m3(h.m2) at 4pa (Pulse equipment), a figure below 5.0 m3(h.m2) would generally then require mechanical supply and extract systems (MVHR or packaged Air Handling plant) to be installed.
We at B&MC carry out the following testing criteria’s and are accredited with Elmhurst Energy.
- Building Air tightness Testing up to 4000m3 utilising Pulse & or Blower Test Equipment to Part L/CIBSE TM23/TSL1 & ASTATT standards.
- Air Tightness testing - Commercial/Domestic, Clean rooms, AOV shafts, Comms room, Sauna rooms to New Build Properties & Existing Properties.
During 2025 there will be a change and update to RDSAP (The domestic dwelling software that is used to establish a domestic dwelling Energy Performance Rating).
What this will mean is that currently when a dwelling is aged during the survey e.g. 1960s built it will, by default apply a Air Permeability figure of 25 m3/hr m-2 – “buildings built to Building Regulations pre 1995 (pre 1994 in Scotland)“ can be overridden with a valid air testing certificate, so if a property has been modernised e.g. double glazed windows, suspended floors sealed and any cracks/joints etc sealed to the fabric this could mean a figure that is a vast improvement on the above and will reduce the EPC rating which will be beneficial to both Home owners, but in particularly landlords with a portfolio of buildings.
During a test we would normally undertake a pre test to establish the initial air permeability figure on a new built property( applies to existing as well), once established the owner or builder can seal up any areas that are highlighted.
Once completed we carry out a final test and record the figures and lodge the reports and certification.
Below is a link to a PDF of facts for Buidling Air Testing, please feel free to download.
| an-overview-of-airtightness-testing.pdf |
For Commercial buildings we can already override the default figures within the software with a valid air test certificate below is an example, when applied with a couple of other measures e.g. cavity wall insulation this can make the difference on properties overall EPC rating and could mean the difference between a non complaint rental property and a compliant one.
On average there was a 11 to 37 point improvement across the figures.
Example of commercial property
Small commercial office unit 2 storey, 61.2m2 built in the 1970s with a default figure of 25 m3/hr m-2 achieved a E119, double glazed and new boiler but default AC efficiency, but no insulation to cavity walls.
10 m3/hr m-2 applied with no other changes achieved an reduction to an E108.
8 m3/hr m-2 applied with no other changes achieved an reduction to an E106.
5 m3/hr m-2 applied with no other changes achieved an reduction to an E104.
With cavity wall insulation factored in;
10 m3/hr m-2 applied with no other changes achieved an reduction to an D86.
8 m3/hr m-2 applied with no other changes achieved an reduction to an D84.
5 m3/hr m-2 applied with no other changes achieved an reduction to an D82.
If there are remedial repairs to seal the fabric of the building e.g. blown/shrunk double glazing seals, sealing penetrations to the fabric/Masticing these are generally easy fixes that can be undertaken to improve the air tightness of a building, coupled with some easy improvements like cavity wall insulation or loft insulation these can make a big improvement on the rating, environmental conditions for occupants and energy used to heat the dwelling which would be reflected in the final EPC rating and associated running costs.
Once the new RDSAP software is released this year we will add an example of a domestic property.
So whilst some buildings achieve a good Air Tightness figure, some rooms/areas may still need remedial works to improve the air tightness and uncontrolled heat loss.
We can also carry out thermal imaging assessments to properties were there are concerns with the air tightness along side an air test.
Previous Page.PAS - 2035
On average there was a 11 to 37 point improvement across the figures.
Example of commercial property
Small commercial office unit 2 storey, 61.2m2 built in the 1970s with a default figure of 25 m3/hr m-2 achieved a E119, double glazed and new boiler but default AC efficiency, but no insulation to cavity walls.
10 m3/hr m-2 applied with no other changes achieved an reduction to an E108.
8 m3/hr m-2 applied with no other changes achieved an reduction to an E106.
5 m3/hr m-2 applied with no other changes achieved an reduction to an E104.
With cavity wall insulation factored in;
10 m3/hr m-2 applied with no other changes achieved an reduction to an D86.
8 m3/hr m-2 applied with no other changes achieved an reduction to an D84.
5 m3/hr m-2 applied with no other changes achieved an reduction to an D82.
If there are remedial repairs to seal the fabric of the building e.g. blown/shrunk double glazing seals, sealing penetrations to the fabric/Masticing these are generally easy fixes that can be undertaken to improve the air tightness of a building, coupled with some easy improvements like cavity wall insulation or loft insulation these can make a big improvement on the rating, environmental conditions for occupants and energy used to heat the dwelling which would be reflected in the final EPC rating and associated running costs.
Once the new RDSAP software is released this year we will add an example of a domestic property.
So whilst some buildings achieve a good Air Tightness figure, some rooms/areas may still need remedial works to improve the air tightness and uncontrolled heat loss.
We can also carry out thermal imaging assessments to properties were there are concerns with the air tightness along side an air test.
Previous Page.PAS - 2035
