Definition of Aluminum Curtain Wall Profiles
A curtain wall is a non-structural outer wall that hangs from the building frame, carrying its own weight and the wind load, but not the floor loads of the building. The aluminum curtain wall profile is the extruded aluminum member that forms the skeleton of this system: mullions and transoms that support the infill panels, connectors and corner elements, and pressure plates and caps that hold the glass or panels in place.
Profiles are produced by extrusion, in which heated aluminum billets are forced through a die to create long sections with a constant cross-section. The die design determines the shape of the profile, including hollow chambers, gasket grooves and screw channels, so each curtain wall system uses a family of specially designed profiles.
Material Properties
Aluminum profiles are light, with a density of about 2.7 g per cubic centimetre, roughly one third of steel, which reduces the load on the building frame and simplifies installation at height. The standard alloy is 6063, heat treated to the T5 or T6 temper, giving tensile strength above 160 MPa and good resistance to wind pressure. For super high-rise or heavy-load projects, high-strength 7xxx series alloys are available.
Aluminum's natural oxide layer resists corrosion, and anodizing or fluorocarbon coating adds a protective finish with a service life of 20 to 30 years, resistant to ultraviolet radiation and atmospheric pollution.
Technical Advantages of the Extruded Section
Extrusion allows multi-cavity and special-shaped cross-sections that would be impossible to produce by rolling. The profiles can be designed with a thermal-break construction, in which interior and exterior aluminum parts are separated by insulating strips of reinforced polyamide, to reduce heat conduction and meet green building standards. Tolerance can be controlled to within about plus or minus 0.1 mm on critical dimensions, and the gasket grooves accept EPDM or silicone gaskets for airtight and watertight joints.
Modular section design supports rapid assembly and unitized curtain wall systems, in which complete wall units are fabricated in the workshop and lifted into place.
Common Profile Types
Mullions and transoms are the primary load-bearing members that support the panels and transfer wind load to the structure. Connectors and corner elements fix and join the profiles to ensure structural stability. Pressure plates and caps clamp the glass from the outside, and decorative lines combine function and beauty to refine the facade. Special profiles accommodate opening windows, sunshades, photovoltaic panels and integration with the building's thermal envelope.
Selection Guidance
For conventional projects, 6063-T5 or T6 profiles are the standard choice. For super high-rise or heavy-load scenarios, select high-strength alloys. Choose fluorocarbon coating for outdoor use, and anodizing or powder coating for indoor and semi-exposed applications. Select the wall thickness, typically at least 1.4 mm for curtain wall profiles, and the cross-section design according to wind pressure, span and thermal requirements. The profile system should be tested as a complete assembly for air permeability, water tightness and wind resistance.
FAQ
Why is aluminum used for curtain wall profiles?
Aluminum combines light weight, high strength, corrosion resistance and precise extrusion into complex shapes, which is exactly what a curtain wall frame needs, and it is fully recyclable.
What is the difference between a curtain wall and a window wall?
A curtain wall spans between floors and carries only its own weight and wind loads, while a window wall sits within the floor slab and transfers its weight to the slab.
Which alloy is used for curtain wall profiles?
6063-T5 and 6063-T6 are the standard grades, with high-strength 7xxx alloys specified for extreme wind loads or very large spans.
What is a thermal-break profile?
It is a profile with interior and exterior aluminum sections separated by insulating strips, which reduces heat transfer and prevents condensation, improving the energy performance of the facade.
How long do aluminum curtain wall profiles last?
With anodized or fluorocarbon-coated surfaces and correct maintenance of seals, curtain wall systems typically last 25 to 30 years or more.
What tests are required for curtain wall systems?
Curtain walls are tested for air permeability, water tightness, wind load resistance and, in many regions, seismic performance, usually per national facade testing standards.