Airtightness & Green Star
Green Building Council Australia has released the new Green Star rating system for the design and construction of new buildings called: Green Star Buildings in late 2020. It is an opportune time to look back on how the Green Star contributed in the progress of airtightness in the Australian construction industry.
| Green Design Version | 1.1 | 1.2 | 1.3 | Green Star Verficication and Handover (2020 Oct) |
|---|---|---|---|---|
| Design | ||||
| Predesign Phase | N/A | N/A | N/A | Mandatory |
| Schematic Design Phase Review | N/A | N/A | N/A | Mandatory |
| Design Development Review | N/A | N/A | N/A | Mandatory |
| Proof of construction inspections for air tightness | N/A | N/A | N/A | Mandatory |
| Air Tightness Testing | Innovation Points Only | Comissioning and Innovation | Comissioning and Innovation | Mandatory |
| Full Building Test Requirement | Required | *Optional instead of 20% (Whole Building Recommended for achieving Good and Best) Refer to * Text Below | *Optional instead of 20% (Whole Building Recommended for achieving Good and Best) Refer to * Text Below | *Optional instead of 20% (Whole Building Recommended for achieving Good and Best) Refer to * Text Below |
| Minimum Percentage of Building to be tested. | ||||
| Minimal acceptable test pressure | Not Defined | 25Pa | 25Pa | 50Pa |
| 10% of the building envelope or 2000m2 | N/A | |||
| 20% of the building envelope or 5000m2 | N/A | 1 | 1 | Not Defined |
| Compulsory Requirment | No | No | No | Mandatory |
| Target Leakage Rates | ||||
| Target Leakage rate 20% of the building envelope or 5000m2 | ||||
| Good Practice | 0 | 1 | 1 | 1 |
| Best Practice | 1 | 2 | 2 | 2 |
| Minimal acceptable test pressure | N/A | 50Pa | 50Pa | 50Pa |
| Points available to the Credit | 2 | 3 | 3 | Not Defined |
* By doing a partial building test(20%), this only benefits the air tightness tester while penalizing the builder. Achieving a target leakage rate for additional innovation points with only 20% of the building being tested can be quite costly and laborious because of the internal hemorrhaging of the building envelope including risers and HVAC connectivity to the rest of the building that isn’t being tested. So if a target leakage rate is being targeted, a whole building should always be targeted to have a fair representation of the air tightness performance. (Not being handicapped by internal leakage, which in most cases was never intended to be air tight.)
Although airtightness specialists have been operating in Australia for over 20 years, they use to be considered by the construction industry as a niche group that would only be consulted in highly specialised projects, such as containment facilities, PC3+ laboratory.
It is fair to say that the Innovation Challenge of Green Star Design and as Built V1.1 introduces airtightness performance to the majority of the builders, architects and consultants. We witnessed how airtightness has changed from a novelty innovation in building sustainability to becoming part of the foundation cornerstone of high performance building in the past five years.
The latest green star Buildings V1 further the industry by introducing the compulsory requirements of addressing the airtightness from the schematic design stage. This is a strategic improvement by encouraging the design team to consider air barrier integrity early, which has the potential to substantially reduce the risk of poor airtightness performance and the cost associated in the construction phase. Efficiency Matrix is the most experienced airtightness consultants in Australia who has been providing design, construction stage advice and consultancy.
Defining an effective air barrier line can substantially improve the constructability and performance of the air barrier. Knowledge about the construction process and materials selection are the key components for successful delivering of an air permeability target.
Efficiency Matrix developed a proprietary App to conduct construction inspections, together with highly experienced consultants and a full array of alternative testing equipment that allows the airtightness level of your project to be evaluated long before the building envelope can be enclosed to perform any type of sample testing.
Efficiency Matrix has developed a continuous air barrier verification methodology which fits right into the soft-landing commissioning approach prescribed by Green Star Buildings V1.
Ask any ESD consultant to list the most important aspects of an energy efficient commercial building, and near the top of the list will be air tightness/build quality.
Implementing airtightness can be more cost-effective and longer lasting than installing
- Solar panels
- LED lighting
- Even a high-efficiency mechanical system
One of the major reasons why a building may fall short of its energy efficiency goals is that it may be leakier than anyone had imagined. The best way to ensure a building actually ends up airtight is to test it.
Air sealing introduces benefits for:
- Energy use,
- Environmental, and
- Comfort benefits.
- Lower maintenance
There are changes coming up for the Green star points associated with Air tightness/Blower door testing.
Common questions we love talking about…
- How much does an airtightness test cost?
- How much can a project save by air sealing?
- What’s a typical result for a project like mine?
- Should I use a blower door fan setup or should I pressurize the building envelope with the HVAC system instead?
Efficiency Matrix has “actual” experience in testing and remediating, some of the largest commercial building for Airtightness in Australia. We have demonstrated assisting our customers to achieve some amazing results time and time again.
Click here for more information about the options for air tightness testing and the drawbacks, of these different options.
