AS/NZS 4284 is the Australian and New Zealand standard for testing building facades. It shows up on compliance packs, in specifications, and in certifier requests — but what the test actually involves, and what the results mean in practical terms, is less widely understood than it should be.
This article explains what AS/NZS 4284 measures, how the test works, what a result like plus or minus 1500Pa at serviceability limit state actually means for a building, and why this report matters for project approvals.
What does AS/NZS 4284 test?
AS/NZS 4284:2008, formally titled “Testing of building facades,” is a system-level test. Unlike material tests such as AS 1530.1 (which tests a small specimen in a furnace), AS/NZS 4284 tests a full-scale facade assembly — panels, fixings, joints, flashings, and all — under simulated environmental conditions.
The test evaluates three things:
Air infiltration. How much air passes through the facade system under pressure. Excessive air infiltration affects energy efficiency, occupant comfort, and can indicate gaps in the system that might also allow water entry.
Water penetration. Whether water passes through the facade assembly when subjected to wind-driven rain. The test simulates rain hitting the facade under sustained wind pressure, and the pass criterion is straightforward: no uncontrolled water penetration to the interior.
Structural performance. Whether the facade system maintains its integrity under wind load. This covers both the serviceability condition (the system does not deform excessively under normal wind) and the ultimate condition (the system does not fail under extreme wind).
All three are tested on the same specimen in a single test sequence, so the results reflect the system’s performance as a whole, not the performance of individual components in isolation.
How does the test work?
The test is conducted on a purpose-built test rig. A full-scale specimen of the facade system is constructed — typically spanning at least one full storey height — and mounted in front of a pressure chamber. The chamber can apply positive pressure (simulating wind pushing against the facade) and negative pressure (simulating wind suction pulling the facade outward).
Air infiltration testing comes first. The chamber is pressurised in controlled increments, and the volume of air passing through the facade is measured at each pressure step. The result is expressed as litres per second per square metre of facade area at a given pressure.
Water penetration testing follows. The facade is subjected to a water spray system that delivers a controlled volume of water across the full face of the specimen while the chamber maintains a specified positive pressure behind the water. This simulates wind-driven rain. The test runs for a set duration, and the interior of the specimen is inspected for any water that has penetrated through joints, seals, or other points.
Structural testing applies increasing pressure in both positive and negative directions. The serviceability limit state (SLS) test checks for excessive deflection or permanent deformation at the design wind pressure. The ultimate limit state (ULS) test pushes beyond that to confirm the system does not structurally fail at higher pressures.
What does plus or minus 1500Pa SLS actually mean?
Pressure in facade testing is measured in Pascals (Pa). A result of plus or minus 1500Pa at serviceability limit state means the facade system has been tested at 1500 Pascals of positive pressure (wind pushing in) and 1500 Pascals of negative pressure (wind pulling out) without exceeding acceptable deflection limits or allowing water penetration.
To put that in context: 1500Pa is roughly equivalent to a sustained wind speed of approximately 175 kilometres per hour acting directly on the facade surface. This is well above normal wind conditions for most Australian metropolitan areas and represents a reasonable design benchmark for mid-rise buildings in non-cyclonic regions.
The “serviceability” part of the term is important. SLS is not about catastrophic failure — it is about the facade continuing to function properly. At SLS pressure, the system should not permanently deform, joints should not open, seals should not fail, and water should not get through. The building remains habitable and the facade remains intact.
The ultimate limit state (ULS) test applies higher pressures to check for structural failure. ULS pressures are typically 1.5 to 2 times the SLS value, depending on the load combination factors. A system tested to 1500Pa SLS might be tested to 2250Pa or higher at ULS.
The specific SLS pressure required for a given project depends on the building height, the site’s wind region (as defined in AS/NZS 1170.2), the terrain category, and the local shielding conditions. The facade engineer determines this based on the project-specific wind load analysis. The specification should state the required SLS pressure, and the test report should demonstrate performance at or above that level.
Why does this test matter for project approvals?
AS/NZS 4284 serves a specific role in the compliance and certification process that other tests do not cover.
It tests the system, not just the material. A facade product might be made from the best materials available, but if the joints leak, the fixings deflect excessively, or the flashings do not manage water properly, the installed facade will not perform. AS/NZS 4284 tests all of these things together, as they will actually be assembled on a building.
It provides evidence for certifiers. Certifiers assessing a facade need to know that the system will resist the wind and rain conditions the building will experience. A product data sheet states what the product is made of. An AS 1530.1 report confirms it is non-combustible. An AS/NZS 4284 report confirms the system, as a whole, can resist the weather.
It supports the Deemed-to-Satisfy pathway. For NCC compliance, the DTS provisions reference performance requirements that AS/NZS 4284 helps to demonstrate. A test report showing adequate weather performance at the required pressure levels forms part of the evidence of suitability package that the certifier reviews.
It reduces project risk. A facade system with a credible AS/NZS 4284 report has been independently verified under controlled conditions. This does not guarantee perfect performance on every installation — workmanship, site conditions, and maintenance all play a role — but it establishes that the system is capable of meeting its performance requirements when properly installed.
What should you look for in an AS/NZS 4284 report?
When reviewing a facade test report or assessing one for a specification, there are several things to check.
The test pressures. Do the SLS and ULS pressures tested meet or exceed the project’s requirements? A report at plus or minus 1000Pa SLS is not evidence of suitability for a building that requires 1500Pa.
The specimen configuration. The test specimen should represent the system as it will be installed on the project. If the report tests a horizontal panel configuration but the project uses vertical installation, the relevance of the report may be questioned.
The testing laboratory. The report should be from a NATA-accredited testing laboratory. NATA accreditation confirms the lab is competent to perform facade testing to this standard.
The report date and product version. Test reports are valid for the product configuration tested. If the product has been modified since the test, the report’s applicability may need to be assessed.
How do V&G products perform under AS/NZS 4284?
Both interloQ and element13 have been tested to AS/NZS 4284:2008 by Ian Bennie & Associates (NATA accreditation number 2371).
The interloQ interlocking rainscreen system was tested under report number 2022-031-S1 and achieved a pass at plus or minus 1500Pa SLS. The element13 solid aluminium panel system was tested under report number 2022-031-S2, also achieving a pass at plus or minus 1500Pa SLS.
Both reports are included in the respective compliance packs and can be referenced directly in specifications and evidence of suitability submissions. If your project requires facade weather performance documentation, our team can provide the reports and discuss how they apply to your specific requirements.
Need AS/NZS 4284 test reports for a project? Talk to our team for compliance packs and technical support.
Related Reading
- AS1530.1 and AS1530.3: What Facade Fire Tests Actually Measure
- Evidence of Suitability Under NCC 2022: What Certifiers Actually Need
- How to Build a Compliant Facade Documentation Pack
- Wind Load Design for Aluminium Facade Systems
Last updated: 4 April 2026