Green Star Airtightness Testing — ATTMA Level 2 | BEO Science NZ & AU
BEO Science — Green Star Airtightness

Green Star airtightness testing —
ATTMA Level 2, NZ and Australia

ATTMA Level 2 certified airtightness testing for Green Star Buildings submissions — NZ and Australia. Full test plan, on-site testing to AS/NZS ISO 9972:2015 and ATTMA TSL2, and submission-ready documentation including area-weighted results for complex typologies.

ATTMA Level 2 AS/NZS ISO 9972:2015 ATTMA TSL2 Green Star Buildings NZ & Australia
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Why ATTMA Level 2 Is Required

Green Star airtightness testing isn't standard blower door testing — the methodology and the credential are different

Green Star Buildings (NZ and Australia) requires airtightness testing of the entire conditioned envelope — not sample units, not representative zones. The test must be carried out by an ATTMA Level 2 accredited tester following ATTMA TSL2 methodology. A Level 1 tester, an uncertified blower door contractor, or a test carried out without a documented Method Statement will not satisfy the Green Star submission requirements.

ATTMA Level 2 accreditation covers large and complex commercial buildings — multi-fan testing for large floor plates, defined protocols for handling service risers, stairwells, plant rooms, and partially conditioned zones. The credential exists because commercial buildings require a substantially different approach from residential testing, and the consequences of a methodology error at submission stage are significant.

The test boundary is rarely straightforward

Commercial buildings combine conditioned zones, unconditioned buffers, service risers, plant rooms with louvred openings, and car parks — none of which are cleanly separated in the design. Defining the test boundary correctly before the test is essential; getting it wrong means invalid results at submission.

Large buildings need multi-fan methodology

Achieving and maintaining 50 Pa across a large floor plate requires multiple fans operating simultaneously. The number of fans, placement, and pressurisation sequence all affect the result. This is ATTMA TSL2 scope — not covered by standard residential testing methodology or equipment.

Sectional testing requires area-weighted results

Where a building can't be tested as a single zone — due to programme, size, or typology — sectional testing is required. Each section is tested separately and results are combined using an area-weighted calculation. This must be documented correctly for the Green Star submission.

Early involvement changes the outcome

The most common cause of a Green Star airtightness problem is not a bad test — it's a building that wasn't designed with a coherent airtightness strategy. Defining the test boundary and identifying problem zones at design stage costs nothing compared to remediation at practical completion.

What We Do

Full-scope Green Star airtightness service

Test Plan & Boundary Definition
Before any test takes place, we review the building drawings and define the test boundary — identifying which zones are conditioned, which are buffer or unconditioned, and how service risers, stairwells, and plant rooms will be treated. We prepare a formal Method Statement documenting the proposed test approach.
  • Drawing review and envelope boundary analysis
  • Zone classification — conditioned, buffer, excluded
  • Fan quantity and placement strategy
  • Formal Method Statement for Green Star submission
  • Early-stage design review available on request
On-Site Testing — ATTMA TSL2
On-site testing using calibrated equipment following ATTMA TSL2 methodology and AS/NZS ISO 9972:2015. Multi-fan setup for large buildings. Coordination with the site team on temporary sealing of intentional openings, plant isolation, and access requirements.
  • Multi-fan pressurisation for large floor plates
  • TECTITE Express result calculation
  • Calibrated equipment — current calibration certificates provided
  • Site coordination — pre-test checklist issued in advance
  • Leakage identification available where result requires investigation
Submission Documentation
Full compliance documentation formatted for Green Star submission — not just a result printout. Includes the Method Statement, test certificate, calibration records, site photographs, boundary diagrams, and area-weighted result calculations where sectional testing was required.
  • Test certificate to AS/NZS ISO 9972:2015 and ATTMA TSL2
  • Method Statement — test boundary, fan placement, sealing approach
  • Calibration certificates for all equipment used
  • Boundary diagrams and site photographs
  • Area-weighted result calculation for sectional tests
Design Stage Support
Early engagement to define the airtightness strategy before design decisions are locked. We review drawings, identify problem zones, and advise on envelope detailing — penetrations, junctions, service interfaces — so the building arrives at test in the best possible condition.
  • Test boundary definition at design stage
  • Airtightness target setting aligned with Green Star credit requirements
  • Penetration and interface detailing review
  • Coordination with energy modelling and HVAC design
  • Shakedown test before linings to identify and resolve leakage early
Commercial Typologies

Where commercial airtightness testing gets complicated

Most commercial buildings in NZ and Australia weren't designed with airtightness testing in mind. The common problem zones are predictable — and manageable, if they're identified before test day.

01
Service risers and vertical penetrations
Service risers that run from basement to roof without fire-stopped airtight seals create a direct leakage path through the entire building envelope. If the riser is inside the test boundary, every penetration into and out of it contributes to the result. We identify riser treatment at design review stage and advise on sealing strategy before the test.
02
Stairwells and atria
Stairwells that connect conditioned floors but are not themselves conditioned present a boundary definition problem. Depending on the Green Star credit requirements and the building design, they may be included in or excluded from the test boundary. The treatment must be consistent across the test and documented in the Method Statement.
03
Plant rooms with louvred openings
Plant rooms are frequently inside the building footprint but open to outside air via louvres. If the plant room is inside the conditioned envelope boundary, the louvres must be temporarily sealed for the test — which may require coordination with building services to confirm isolation of mechanical plant. If the louvres can't be sealed, the plant room may need to be excluded from the boundary and the result calculated accordingly.
04
Integrated car parks and loading areas
Basement car parks and ground-floor loading bays are typically unconditioned and excluded from the test boundary — but the interface between the car park and conditioned floors above is a significant leakage path. The floor/ceiling assembly at this interface needs to be part of the airtightness strategy regardless of whether the car park itself is in scope.
05
Mixed-use buildings and tenancy boundaries
Buildings with multiple tenancies, mixed residential and commercial floors, or staged handover may need sectional testing — with each section tested independently and results combined using an area-weighted calculation. The Green Star submission must document how the weighted result was calculated and confirm that all sections meet the applicable benchmark.
Green Star Benchmarks

Air permeability targets for Green Star Buildings

Green Star airtightness benchmarks are expressed as air permeability — q50 in m³/(h·m²) of envelope area at 50 Pa. The applicable benchmark depends on building type and ventilation strategy. All results must be calculated using the area-weighted methodology where sectional testing is applied.

Building type / ventilation strategy Target q50 Notes
Mechanically ventilated offices & commercial ≤ 2.0 m³/(h·m²) Most common commercial typology
Dwellings with MVHR or mixed-mode ventilation ≤ 1.0 m³/(h·m²) Multi-residential with heat recovery
Naturally ventilated dwellings ≤ 5.0 m³/(h·m²) Less common in Green Star Buildings context

Benchmarks are indicative — Green Star credit requirements should be confirmed against the current Green Star Buildings technical documentation for your project. Contact us to discuss the applicable benchmark for your building type and credit target.

Deliverables

What the Green Star airtightness commission produces

Standard deliverables — all commissions
  • Method Statement — test boundary, fan placement, sealing approach, zone classification
  • Test certificate to AS/NZS ISO 9972:2015 — measured data, calculated q50, pass/fail
  • ATTMA TSL2 compliance documentation
  • Equipment calibration certificates — current at time of test
  • Boundary diagrams and annotated site photographs
  • Area-weighted result calculation where sectional testing was required
  • Leakage identification report where investigation was carried out
  • Report formatted for Green Star Buildings submission
Need standard residential or commercial blower door testing? For non-Green Star projects — Passive House, Homestar, NCC compliance, or general airtightness testing — see our main airtightness testing service.
See airtightness testing →
FAQ

Common questions

Is ATTMA Level 2 certification required for Green Star, or will Level 1 suffice?
Green Star Buildings requires ATTMA Level 2 for commercial building testing. ATTMA Level 1 covers residential and small commercial buildings to ATTMA TSL1 methodology. Large commercial buildings require TSL2 — which is the Level 2 credential. Submitting a test carried out by a Level 1 tester, or without a documented Method Statement, will not satisfy the Green Star assessor's requirements.
When should we engage you in the project programme?
As early as possible — ideally during design development when the building envelope and service layouts are being resolved. The test boundary definition and Method Statement should be agreed before construction begins. Early engagement means we can flag problem zones — service risers, plant room interfaces, stairwells — while they're still being designed, not after they're built. The test itself happens near practical completion, but the strategy needs to be in place from the start.
Can the building be tested in sections if it can't be pressurised as a whole?
Yes — sectional testing is an accepted methodology under ATTMA TSL2 where the building size or configuration makes whole-building pressurisation impractical. Each section is tested independently and results are combined using an area-weighted calculation based on envelope area. The Green Star submission must document the methodology and confirm that the weighted result meets the applicable benchmark.
Do you operate in Australia as well as New Zealand?
Yes — BEO operates across both NZ and Australia. Green Star Buildings applies in both markets and the ATTMA TSL2 methodology and AS/NZS ISO 9972:2015 standard apply equally. Contact us to discuss your project location and confirm availability and travel arrangements.
What happens if the building doesn't meet the Green Star benchmark?
A result above the benchmark means the Green Star airtightness credit is at risk. We provide leakage identification under pressurisation to locate specific problem areas, and can advise on remediation priorities — which leakage paths are contributing most to the result and where sealing effort is best directed. A retest following remediation confirms whether the benchmark has been achieved. Early-stage shakedown testing significantly reduces the likelihood of a fail at the certification test.
ATTMA Level 2 airtightness testing for Green Star — NZ and Australia
Book a consultation to discuss your project, confirm the test boundary, and agree on the programme. Early engagement is always worth it.
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denise@beoscience.com · +64 210 239 4980 · beoscience.com