Before a facade system goes onto a tower, it can be made to survive its whole service life in a week — hurricane-force pressure, driven rain, earthquake racking, impact — inside an independent laboratory. This is what that gauntlet looks like, and why we submit to it.
A performance mock-up is not a sample — it is a full-scale, two-storey section of the actual facade, panels and corner conditions included, built with the same extrusions, glass, gaskets and sealants that will go on the building, and installed into a steel test chamber that stands in for the structure. Every test is witnessed — client, architect, facade consultant, PMC — and every reading goes into the record.
A sealed steel enclosure in which centrifugal blowers can pull the air pressure thousands of pascals above or below atmosphere — simulating wind pushing on, and sucking at, the wall.
Displacement transducers on every mullion measure deflection to fractions of a millimetre while the wall is under load; airflow meters and manometers catch every leaked cubic metre.
A grid of spray nozzles delivers a calibrated cloudburst across the whole specimen — and for the dynamic test, an aircraft propeller drives that water at the wall as wind-blown rain.
The sequence is deliberate: after every structural ordeal, the wall must prove it is still weather-tight. A facade that holds its load but starts leaking has failed.
The specimen is loaded to half its design wind pressure and released — settling the assembly the way the first storm would, so every later reading is honest.
With the chamber pressurised, the leakage through the wall is measured — first with the specimen sealed in polythene, then exposed; the difference is the wall's true leakage. The permitted numbers are small: fractions of a cubic metre per hour for every square metre of facade.
Fifteen minutes of calibrated, uniform rain across the full face of the wall while the chamber holds a pressure differential — the equivalent of a monsoon squall pressing water at every joint. Not one drop may reach the inside uncontrolled.
The same rain, now driven by an aircraft propeller. Static pressure finds the weak gaskets; turbulence finds everything else — water made to climb, swirl and hunt for a path the way real wind-blown rain does.
The wall is taken to its full design wind load — pushed and pulled — while transducers log the deflection of every framing member. Mullions must stay within the codified span limits, and spring back with next to no permanent set when the load comes off.
Having been flexed to its design load, the wall faces the rain again. This is the point of the sequence: weather-tightness is only real if it survives the structure working.
Hydraulic jacks rack the floors sideways, then displace them vertically — cycle after cycle — the way an earthquake or a live-loaded slab moves a building. No broken glass, no dislodged gasket, no cracked sealant, and the vents must still open and lock.
After the earthquake, the rain. The wall has now been settled, pressurised, flexed and racked — and must still be dry.
The final structural act: one and a half times the design wind load, in both directions. A safety margin proven physically, not just calculated — no breakage, no anchor damage, hardware still working.
Gaskets are deliberately disturbed and the wall re-tested for leakage; the facade takes impact loads; and the restraints that hold maintenance cradles are pulled to prove they hold. The details that never make renders — and decide how the building ages.
A performance mock-up usually begins with pre-tests — and pre-tests find things: a weep hole that needs opening, a joint that wants more sealant, a lock that needs upgrading from two points to four. Each finding is rectified on the specimen, retested, and recorded in the final report with dates, readings and photographs.
That is not the test failing. That is the test working — every weakness found in the chamber is a weakness that never reaches the building. Be wary of any facade that has never been made to fail at anything.
Testing is carried out by independent, NABL-accredited laboratories (ISO/IEC 17025) — the lab runs the chamber, the lab signs the report. The benchmarks are the international facade standards:
Installed facades are hose- and spray-tested on the building to AAMA 501.2 — the same discipline, applied to the real wall, storey by storey.
Witnessed pull-out tests load the actual anchors in the actual slab edge — the connection between facade and structure proven where it matters.
Extrusions go to NABL laboratories for tensile and chemical verification; structural silicone is subject to the sealant manufacturer's adhesion and compatibility testing before a single panel is glazed.
Separate from performance testing, every project gets approval mock-ups of its unique facade elements — reviewed by the architect, consultant, client and PMC before fabrication. See how we work →
Performance mock-up tests are witnessed by the client, architect, facade consultant and PMC at independent testing laboratories, including NABL-accredited facilities — and signed off only when the wall has done everything the specification demanded.
