What is Air Permeability?
Air permeability is the uncontrolled flow of air through gaps and cracks in the fabric of the building envelope. This is sometimes referred to as infiltration or draughts.
Why is Air Permeability Testing Important?
Air Permeability Testing is an important phase of construction, as the outcome could significantly impact the building's energy efficiency ratings. Energy efficiency is all about control over heat and airflows, and to control air, you must first contain it.
Constructing an energy efficient building means defining an air barrier separation, using appropriate sealing products, and also ensuring they are installed correctly during construction. The Air Permeability Test (APT) identifies the leakage rate of the building under a test. If the installation contractors have done an excellent job with sealing and creating an airtight barrier, the testing will pass straight away with no remedial work required.
Or, the test could fail, which often leads to finger pointing amongst contractors. The responsibility for the testing passing is an ongoing collaborative effort. Trying to remedy leaks at the end of construction can be expensive, as solutions often lie beneath the surface. This is not a situation anyone wants. Commercial and domestic buildings each have specific types of tests that can provide information on the air permeability for that building.
Blower Door Testing
A Blower Door Test detects and measures any air leakage from the building envelope. The conditioned building envelope is the air barrier determined during the design phase. Depending on where the air barrier is determined, dictates the calculated building envelope. The concept behind this is called Passive House.
Air permeability is measured with a Blower Door Test. The blower door test is completed both during and after construction. During construction once the air tightness layer is completed – the blower door test can be used to detect air leakages before wall and exterior coverings are attached. Saving time and potential post construction cost for the building owner. Once construction is completed the blower door test can then be completed again as the official verification of the passive house construction.
The demand for air permeability testing is gradually increasing here in Aotearoa. The New Zealand Green Building Council have recently released Green Star Homes, which calls for mandatory air tightness targets for all homes in all climate zones. These tests must be conducted by an ATTMA member and lodged with the ATTMA. There will be an ATTMA Lodgement Certificate issued to be used as proof of the test results. AirRated® are accredited Level 1 members of this association.
For more information on this visit the ATTMA & NZGBC websites.
When does a building require a Blower Door Test?
In 2019, the new regulations under Healthy Homes Standards were released. The Healthy Home Regulations are comprised of 5 standards which outline the Landlords legal responsibility to ensure that their tenanted properties are a healthy, warm, and comfortable environment for tenants.
"Landlords must make sure the property doesn’t have unreasonable gaps or holes in walls, ceilings, windows, skylights, floors and doors which cause noticeable draughts. All unused open fireplaces must be closed off or their chimneys must be blocked to prevent draughts" https://www.tenancy.govt.nz/healthy-homes/draught/
Landlords cannot use the age of the house as an excuse to adhere to this standard and failure to meet the regulations is a breach of the Residential Tenancies Act 1986 and can result in fines. Fixing a draught results in energy efficiency for the tenant who can heat the home at a lower cost. For the landlord, potential future moisture issues are removed.
Passive House Design is a fabric-first concept that focuses on creating an energy efficient home that is healthier, more comfortable, and saves up to 90% of conventional housing's energy costs. In New Zealand, homes that are constructed to Passive House requirements will require a Blower Door Test by an accredited ATTMA tester to verify air tightness of a household. Read more about passive house here. The ATTMA TSL1 procedural standards and guidelines are based on AS/NZS ISO9972:2015 - Thermal performance of buildings - Determination of air permeability of buildings - Fan pressurisation method.
AirRated® can also provide Blower Door Testing for some commercial settings too. During the construction of these types of rooms, air permeability testing should be carried out to ensure an airtight seal is achieved. Using thermal imaging and other diagnostic techniques, we can identify leaks within the building envelope
Benefits of testing for air leakage
AirRated can also offer
Why choose AirRated?
AirRated® are independently accredited Level 1 members of The Air Tightness Testing & Measurement Association (ATTMA). This association is recognised in New Zealand to follow air tightness testing procedural standards, (TSL1) and BS EN:13829 (2001), demonstrating knowledge and understanding to test both commercial and domestic developments in accordance with relevant building regulations.
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