Elissa Stirling took two practical high-rise façade risks a stormier climate is sharpening, awning windows torn off by wind, and condensation, with cheap fixes for both: a continuous hinge and anti-lift block, verified in the factory, and weather barriers and ventilation to keep surfaces dry. She also sets out the work of the Society of Façade Engineering’s ANZ hub.
No engineer, she hopes, should ever have to field a call reporting an awning window ‘sucked off’ a building, but her remedial and diagnostic practice does, in fact, see exactly that.
The dominant-opening problem is a code change. A 2021 amendment to the wind-actions standard altered how the internal-pressure factor is applied, raising the loads on façades, mullions, glass, doors and windows, especially when an opening is left open in a high wind. A sliding door open at a building’s corner lets wind in, raising internal pressure while suction continues outside; a large open awning window does the same. The result is a demand for deeper mullions and thicker glass, and for the open case to be designed at all.
Her two takeaways for awning windows on tall buildings were refreshingly cheap. First, a continuous, piano-style hinge along the top for continuous mechanical restraint, close to cost-neutral. Second, an anti-lift block, so that hinge cannot lift off the building under suction. Both, she stressed, must be verified as actually installed in the factory, not merely drawn, then, even if the hardware fails, the sash stays attached. She walked through the hardware (cam handles, latch plates, stays, restrictors) and the limits of the testing: the NCC tests an awning window to ultimate loads only closed and locked, plus fall-prevention and operational-force tests, and the ever-larger, heavier awning windows now specified (over 100 kg, laminated for acoustics) are starting to fail the force-to-open test.
The second risk, condensation, is the counterweight, and the reason she would tell you to make those same windows bigger. As warm, moist internal air meets cold surfaces, condensation brings mould, staining and decay; managing it means weather barriers, ventilation and airtightness working together to keep vapour moving and surfaces dry. The design tension is real: wind loads argue for smaller openings, condensation and ventilation for larger ones, and resolving the two is the façade engineer’s job.
Stirling also flagged the profession itself. As vice chair of the Society of Façade Engineering’s ANZ hub, the regional arm, co-founded with Arup’s Rob Buck, of the UK-chartered body, she pointed to its work: developing the façade design-practitioner scope under New South Wales’ Design and Building Practitioners Act, contributing to Australian standards including the AS 4200 pliable-membrane standard, and pressing for façade engineering to be recognised as an area of practice by Engineers Australia. The thread across both her risks and her advocacy is the same: turning hard-won practical knowledge into design that is resilient by default.