High-Rise & Seismic-Zone Facade Fenestration
Drift-Tolerant Frames Rated to Design Wind Pressure at Height
Upper elevations of a tower carry two structural demands that a single rigid frame cannot resolve on its own: design wind pressure that rises with height, and inter-storey drift during a seismic event or under wind-induced sway. A system specified for a low-rise building usually passes the pressure check and still fails at the glass edge, because a rigidly tied frame transfers storey movement straight into the glazing. This package addresses both conditions together, combining drift-tolerant mullion connections, pressure-equalised drainage and sections sized to a deflection limit rather than to a nominal span. Every performance figure is fixed per project from the structural engineer's wind and drift calculation, since a tower in a low-seismicity region does not need the movement allowance required on an active fault line. Shop drawings are issued with the mullion calculation, the drainage path and the perimeter joint detail so the site team can install to the assumed tolerance.
Key Features & Benefits
Drift-Tolerant Frame Connections
Slotted mullion brackets and oversize fixing holes let storey movement be absorbed by the frame instead of the glass edge, with the movement allowance taken from the project's drift calculation rather than from a catalogue default.
Pressure-Equalised Drainage
Stepped sill chambers and baffled outlets equalise pressure across the gasket line, so water at design wind pressure is drained out rather than pushed inward past the weather seal.
Mullion Sizing to a Deflection Limit
Mullion depth and wall thickness are selected against a deflection limit such as L/175 at design pressure, not against span alone, and the calculation is issued with the shop drawings for review.
Thermal Break and Warm-Edge Continuity
Above roughly 60 metres, wind-driven moisture and stack effect make condensation the visible failure; a polyamide thermal break and warm-edge spacer keep the inner frame surface above dew point at the specified indoor humidity.
Factory Glazing with a Tolerant Site Sequence
Units are glazed and sealed in the factory, then installed in a sequence that lets structural tolerance be absorbed at the perimeter joint rather than transferred to the glass or the anchor.
Technical Specifications
- Design Wind Load
- 2.5 to 5.0 kPa, per project calculation
- Deflection Limit
- L/175 at design pressure
- Water Penetration
- ASTM E331, Class 5A at 600 Pa (project-specified)
- Air Leakage
- ASTM E283, Class 4
- Movement Allowance
- Plus or minus 10 to 25 mm drift, project-specific
- Frame Material
- 6063-T5 or 6063-T6 aluminium
- Wall Thickness
- 2.0 to 3.0 mm at mullion and transom
- Glass Build-up
- Laminated Low-E double or triple glazed to the U-value target
- Finish
- PVDF to AAMA 2605, or anodised 20 microns and above
- Warranty
- 10 years structural, 5 years finish
Ideal Applications
Ready to Discuss Your Project?
Our technical team is ready to help you select the right fenestration solution for your specific requirements.
