Commercial air leakage testing otherwise known as commercial blower door testing enables:
- Smoke sealing and protecting areas of refuge (ensures in the event of a fire, smoke does not enter another part of the building) This is especially useful in the oil & gas industries especially on oil rigs.
- Enables significant energy efficiency benefits in commercial buildings.
- Clean Rooms – Very useful in hygienic areas eg. hospitals or high precision manufacturing
- Stairwell pressurization & Control Rooms
- Under floor plenums (UFAD)
Air Permeability rate
|CFM 75Pa/ft2||Additional Energy||Impact on Indoor Air quality|
The United States Army Corps of Engineers specifies:
All new buildings and buildings undergoing major renovations shall pass an air leakage test, the results of which must be less than or equal to 0.25 CFM per square foot of exterior envelope at 0.3 inch of water gauge [75 Pa] pressure difference.
The UK is the only country that currently requires large buildings to pass an air leakage test.
Does Australia have a standard for Commercial Air Leakage Testing?
Yes!, AS/NZS ISO 9972:2015
What is commercial Blower Door Testing?
Air tightness testing is an air permeability test, which is carried out by a professional testing company to identify the volume of air that can escape from a building. ATTMA Part TSL1 and ATTMA Part TSL2 in Non-dwellings provide a clear guidance on how to make buildings more energy efficient, cost effective and comfortable.
Airtight buildings prevent conditioned air escaping from the building and restricts any unwanted cold winds/draughts entering the building. With air tightness in check, air handlers do not need to work as hard to pressurize the whole building envelope positively.
Here is a table of the key differences between the 2 most popular standards.
|Max. Bias||42%||30% & 10%||accuracy|
|Temperature & wind restriction||Yes||No||flexibility|
|Min. test pressure||10Pa||25Pa||stability|
|Min. # builder/flow readings||5||120||accuracy|
|Min. test point interval||10s||20s||accuracy|
American Society for Testing and Materials VS United State Army Corp Engineers
What is the test procedure?
Air tightness testing is carried out in accordance with the procedures detailed in ATTMA TSL1 for Part L1A conservation of fuel and power in new dwellings and ATTMA TSL2 for Part L2 conservation of fuel and power in new non-dwellings.
Type of Building Air Permeability
m3/h/m2 @ 50Pa
m3/h/m2 @ 50Pa
Air Change Rate (ACH) @ 50Pa Air Permeability
m3/h/m2 @ 50Pa
Best Practice Good Reality
Offices N/A TBA
Naturally Ventilated 3 7 N/A TBA
Mixed 2.5 5 N/A TBA
2 5 N/A TBA
Factories/Warehouses 2 6 N/A TBA
Superstores 1 5 N/A TBA
Schools 3 9 N/A TBA
Hospitals 5 9 N/A TBA
Museums, galleries and archival stores 1 1.5 N/A TBA
Cold Stores .2 .35 N/A TBA
Passive House Standard N/A <1 .6 TBA
Passive House Retrofit N/A <1 1 TBA
Air permeability is expressed as volume flow per hour (m3 h-1) of air supplied to the space per square metre (m2) of envelope area for an internal to external pressure difference at 50 Pa.
The air permeability test involves connecting a series of small fans, or a large fan, to a suitable aperture in the building envelope and pressurizing it over a range of pressure differences at least above 30Pa for an indicative flow reading extrapolated to 50Pa. The USACE standard uses 75Pa as the ultimate pressure to achieve an accurate leakage rate.
Here is a table documenting the differences in pressure each standard requires.
|Origin||USA||Canada||Europe||UK||USA||WA State||North America|
|Range||10 to 60Pa||15 to 50Pa||10 to 50Pa||10 to 60Pa||25 to 75Pa||25 to 80Pa||10 to 60Pa|
Air volume flow rate through a blower door fan (equal to the air escaping through the building envelope, such as gaps and uncaulked holes) and the pressure difference across the building envelope are recorded at each blower door fan speed.
In calculating air permeability, corrections are made for temperature and barometric pressure.
What types of preparations are required before the air tightness tests?
- Access in and out of the building during a test is not possible.
- Before the test is carried out, exhaust fans, kitchen hoods, and ventilation systems must be thoroughly sealed. Sealing can be achieved with covering the grilles with plastic tape. Drainage traps should also be prepared.
- While the pressurization test is being carried out all external doors and windows must be closed and secured to avoid them being blown open. It is also recommended to tape off all the vents on windows. Internal doors should be wedged open during a test to avoid them inadvertently slamming shut.
- There are no health risks to site workers who will remain in the building while the air pressure test is being carried out.
How long would it take to carry out the test?
The test will take approximately 60-120 minutes for residential properties and whole days/multiple days for some commercial buildings depends on the size of the building and depending on problems. After the test is carried out, thermal imaging or smoke is used to troubleshoot the building envelope, should the result not be desirable.
Rough estimate of Retrotec high powered fans required for a job depending on leakiness.
Testing to 10m3/h/m2 @ 50Pa
|m3 Air Volume||Fans Required|
|17000+||Building must be inspected|
*Note the leakier the rate, the more fans that are required to do an area.
Testing to 5m3/h/m2@50Pa (Recommended leakage rate)
|m3 Air Volume||Fans Required|
|37000+||Building must be inspected|
Is air permeability testing mandatory?
An article Written by Sean Maxwell from Efficiency Matrix on the subject.
What Areas can we service?
We can service all over Australia.
- Christchurch (New Zealand)
- Auckland (New Zealand)
Air Change an Hour@50Pa (ACH@50) and Air Permeability air leakage@50Pa (m3/h/m2@50Pa).
- Buildings 4000m3+ are defined as large buildings and should be measured using an air permeability rate (m3/h/m2@50Pa).
- Buildings that are smaller than 4000m3 are measured using ACH@50Pa.
Smaller buildings proportionately have a smaller volume compared to the surface area of the building envelope so an ACH value is harder to achieve and more beneficial.
Larger buildings proportionately have a smaller surface area compared to the volume so an air permeability rate is harder to achieve and more beneficial to the energy efficiency of the building.
What is the equivalent leakage rate of USACE .25/CFM/ft3@75Pa compared to an Air permeability rate @ 50Pa?
Guarded Blower Door Testing
Efficiency Matrix, has a vast amount of experience in isolating air leakage into the main part of a building in order to get an understanding of how the facade building envelope performs or understanding how much leakage is occurring between one area to another.