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Curtainwall Infinity System

QUOTE| |800.426.0279

The SteelBuilt Curtainwall Infinity™ System can use as a back mullion almost any type of custom steel member, allowing architects and designers to use larger areas of glass, smaller frame profiles and greater free spans. The design flexibility allows curtain walls to be incorporated into a nearly limitless range of building types, designs, and performance requirements.

“TGP’s steel curtain wall system made it possible for us to meet the project’s unique geometrical needs without compromising on appearance.”

-Windom Kimsey, design principal and president of TSK Architects


  • Almost any type of custom steel member can be used for a back mullion–such as stainless steel, box, I-beams and T-shapes
  • Offers all the advantage of steel: larger free spans, narrower sight lines and improved thermal performance 
  • Narrow sight line of 1-3/4" (45 mm) for interior only or 2-3/8" (60 mm)
  • Variety of system depths
  • Infill options up to 2"
  • Painted finishes in standard and custom choices
  • Silicone compatible glazing materials for long-lasting seals
  • Shear block fabrication method
  • Compatible with SteelBuilt Window & Door® Systems 

Optional Features

  • Structural silicone is available in 2- or 4-sided applications for a smooth monolithic appearance. See SteelBuilt Curtainwall Infinity SSG.
  • Stainless steel cover caps
  • Custom extruded aluminum cover caps


Frame tests performed in accordance with:

AAMA 501.1 Dynamic Water Penetration
ASTM E283 Air Performance
ASTM E331 Static Water Penetration
ASTM E330 Structural Performance

Back Mullions

Almost any type of custom steel member can be used for a back mullion–such as stainless steel, box, I-beams and T-shapes.


Box Beam

T-Shape with SSG


SteelBuilt Curtainwall® Family  vs.  Typical Aluminum Curtain Wall

Design Wind Load: 30 psf
Module/Vertical to Vertical spacing:5'-0"
Rectangular Verticals: Captured

Design Ideas

Curtain Wall Basics

Learn about the different types of curtain walls, steel vs. aluminum systems, product testing, how curtain walls can contribute to LEED standards, curtain wall applications, innovations, challenges and more.

See Curtain Wall Basics

Steelbuilt Design Options

Explore this interactive tool to get a feel for the various benefits and options available when building with SteelBuilt Curtainwall® Systems.

See Design Options

The time, in minutes or hours, that materials or assemblies can be expected to prevent flames and smoke from spreading.

As heat develops within the source area, pressure within the enclosed room begins to build relative to the pressure outside. Once the fire reaches equilibrium in the positive pressure zone, smoke, hot gases and flames are forced through any openings in the door or window assembly. Testing to the UL 10C standard more closely simulates real fire conditions.

Blocks radiant and conductive heat transfer from one side of the glass to the other. A required characteristic of glass used as a wall.

Classified and labeled by Underwriters Laboratories, Inc.® (UL), an independent product safety certification organization.

Immediately following a furnace test, heated glass is subjected to water from a fire hose. The cooling, impact and erosion created by the hose stream tests the integrity of the glass. In the U.S., the hose stream test is required for all fire ratings over 45 minutes (all fire ratings require it in Canada).

Available as a temperature rise door with Pilkington Pyrostop® fire-resistive-rated glass for 60-90 minute applications

Temperature rise doors provide a barrier to radiant and conductive heat transfer.

Available in stainless steel frame finish options for increased design flexibility.

Building codes clearly define hazardous locations where impact safety glass is required. Glass with this designation has been tested to meet impact safety requirements required for areas such as doors, sidelights, and areas close to the floor.

FireLite IGU is a fire-rated insulated glass ceramic unit that also complies with energy codes. It is designed for use in exterior applications where energy codes require an insulated product, or for interior applications with special needs such as sound reduction.

Withstands continuous temperatures to 1292° F for use in high efficiency heating appliances.

The ability of glass ceramic to withstand sudden heating, cooling, or both without cracking, shattering or exploding out of the frame.

The ability of the glass to stop various types of ammunition. Ratings are assigned in levels from 1 to 8, with a Level 8 rating being the highest (able to stop a 7.62mm rifle lead core full metal copper jacket, military ball).

The capacity of an element in a building structure to support a weight in addition to its own.

Listed and labeled by Intertek, an independent assurance, testing, inspection and certification organization.

Glazing designed to increase the amount of time required to gain entry. This additional time is intended to allow for the enactment of lock-down protocols and to allow for the arrival of emergency response teams. May be used in areas with high risk of prolonged attack or in critical areas such as vestibules. Forced entry resistant glazing should also resist penetration from hand-held or hand-thrown objects such as hammers, crowbars, bats, knives, bricks and rocks. (Source: NGA Glass Technical Paper FB71-21)