Hybrid Point-Supported Facade Technology
A NEW LEVEL OF CURTAIN WALL PERFORMANCE
by Franz Safford, CEO and Founder of Innovation Glass
Quietly since 2006, a new curtain wall solution strategy has entered the built environment to offer better solutions to modern building envelope requirements. Referred to as Hybrid Point Supported or HPS, this approach serves to significantly minimize the metal in the final facade assembly thereby reducing complexity and cost as compared to conventional curtain wall systems such as store front, window wall and unitized types. The deletion of metal also serves to enhance facade transparency.
The leader in this category of curtain walls is the VS1 system offered by Innovation Glass LLC headquartered in New York. Over 125 projects have been completed in the USA, Europe, South America , the Middle East and Asia. Extensive 3rd party performance mock up testing, thermal performance analysis and numerous empirical component tests have repeatedly validated the system’s performance giving clients confidence to use it on ever larger projects worldwide.
VS1, Hybrid Point-Supported Glass Curtain Wall Technology
TECHNOLOGY PERFORMANCE
SUPER TRANSPARENT STRUCTURAL CLEAR SPANning glass WALLS
Glass clear spans up to 65’+.
World record was set in 2009 at 42’ clear span for an unreinforced aluminum curtain wall at the Adobe Utah Campus, UT (seismic zone 4). (Fig. 1.)
Elimination of horizontal framing.
No secondary steel framing required, achieving a higher level of facade transparency. (Fig. 2.)
Dies up to 24” (94mm) in depth allow extrusions to be pushed up to +/-50 long and spliced together as needed with concealed internal splice plates, offering the lowest cost glass long span facade solutions in the market.
BEST IN CLASS THERMAL PERFORMANCE
0.04 average increase in BTU/h-FT2-F for system U-value over COG U-value.
The inherent thermal improvement of separating the glass from the face of the mullion framing as well as the elimination of 50% of the metal framing typically contained in a standard curtain wall system, the horizontals, results in superior thermal performance.
HIGH QUALITY LONGTERM WEATHER INTEGRITY (NO LEAKS)
Barrier system to achieve weather-ability.
The leading HPS system has primarily used sealant products by DOW Corporation to achieve the weather seal.
DOW offers its 10 year VIP warranty on HPS projects that are properly registered with the company.
Structural Dowsil 795 is used as the sealant to greatly increase the durability of the weather seal.
By offsetting the glass panels from the face of mullion coupled with the absence of horizontal framing the glass joints are visible in their entirety from the interior permitting 100% access for superior quality control.
EXCELLENT SEISMIC ACTIVITY ADAPTATIONS
The standard 1” (2mm) glass butt joints in each direction accommodate significant building sway without failure.
jumbo glass panels accommodated
Because HPS systems generally do not have horizontals the systems can accommodate jumbo glass panels. (Fig. 4.)
Solves complex geometries cost effectively
By eliminating the horizontal framing and letting the glass contribute more of the structural support capacity of the façade complex geometries are readily achieved. Multi-folded or segmented curved curtain walls are able to be realized at unprecedented value compared to conventional curtain wall technologies. (Fig. 5.)
Figure 1 · Long span glass curtain wall · Adobe Utah Campus
Figure 2 · Reduction of horizontal metal · Osborne Legacy Complex
Figure 3 · Weatherproofing detail
Figure 4 · Jumbo glass units · Gateway Plaza
Figure 5 · Complex geometry · Cummins Technology Center
TECHNOLOGY DETAILS
VARIETY OF CURTAIN WALL MULLION PROFILES AVAILABLE
Over time the VS1 system has accumulated a variety of mullion shapes to best respond to structural and aesthetic project requirements. (Fig. 6.)
Glass Attachment Options
Glass attachment options are concealed toggle (Fig. 7), cassette (Fig. 8), and patch (Fig. 9). Glass is offset from face of mullion by +/-2”.
Direct glaze options are available if you wish to decrease the system depth by bringing the glass in contact with a gasket at the face of mullion. (Fig. 10.)
Figure 6 · VS1-A Mullion Library
Figure 7 · VS1-A110, standard fitting + toggle
Figure 8 · VS1-A120, modified fitting + cassette
Figure 9 · VS1-A100, standard fitting + patch
Figure 10 · VS1-A210, direct glaze + toggle
minimalist FACADE detailing
All-Glass Corners
Gravity loads from the corner glass panels are supported by a tension rod or 1”x1” tube along the vertical corner joint, while lateral forces are transferred around the corner via structural silicone. (Fig. 11.)
Low-Visibility Joint Design
The HPS methodology reduces the sight lines of glass joints. Concealed gravity shelves and the absence of horizontal mullions further allows for design freedom in high transparency curtain wall design, for example offset glass grid patterns. (Fig. 12.)
Clean Perimeters
Minimalist interfaces with adjacent construction are possible with HPS solutions. (Figs. 13 & 14.)
Figure 11 · All-glass corner · Statue of Liberty Museum
Figure 12 · Offset glass joints · Resorts World Casino
Figure 13 · No horizontal metal at sill or head, maximizing transparency · Harwood International
Figure 14 · Clean interface with adjacent wall · St. Louis Holocaust Museum
Figure 15 · VS1-A100, aluminum mullion
Figure 16 · VS1-G100, glass fin
Figure 17 · VS1-T100, timber mullion
Figure 18 · VS1-S200, steel mullion (direct glaze)
MULLION MATERIAL VARIATION
VS1 framing is available in four materials: aluminum (Fig. 15), glass (Fig. 16), timber (Fig. 17), and steel (Fig. 18).
HPS glass curtain walls can be built to match the aesthetic, performance, and sustainability goals of the designer.
REVERSIBLE mullion designs
The designer is able to switch the mullions to the exterior as needed to express a vertical aesthetic. (Fig. 19.)
The mullions can be varied from interior to exterior across the facade to create a dynamic visual impact.
The widths of the mullions can be altered to further create texture in the facade.
ATTACHMENT OF SUN SHADING ACCESSORIES
Various shading elements can readily be attached to the VS1 facades as required, in some cases after initial installation of the curtain wall. (Figs. 20 & 21.)
Curtain WALL TO ROOF TRANSITIONS
The one-way framing strategy of the HPS approach allows the wall mullions to seamlessly transition to roof mullions creating an integrated skylight with the same system details. (FIg. 22.)
The VS1 system is a standard curtain wall system. Unlike other standard systems, however, VS1 is comprised of a “variable” standard “kit-of-parts” that allows the designers to influence the aesthetic outcome to closely match their ideal programmatic design goals. Instead of the design having to compromise to system limitations (the introduction of a heavy steel horizontal beam to reduce the wall spans) the system responds to the design intent by evolving as needed to meet the desired aesthetics. This is unprecedented in the curtain wall industry. A designer can specify an HPS curtain wall on 10 different projects and have 10 different visual appearances. This is an exciting development in the industry as it reduces the often monotony of similar appearing exterior facades.
VS1 Installation PROCESS
Although the design community has embraced the aesthetic beauty of the system it is notable that the glazing community has given the system high marks as well. The system details were deliberately designed to allow ease of installation and adjustability not possible with conventional systems. (Fig. 23.) The VS1 framing and accessories are intuitively detailed to allow even a first-time installer to have a successful project. Key to industry-wide adoption of HPS curtain walls is that they need to be easy to install. Gauging from the number of repeat users, that goal has been achieved.
Figure 19 · Exterior mullions on podium facade · St Regis Tower
Figure 20 · Slanted exterior metal fins · Earl Shapiro Hall
Figure 21 · Exterior-mounted sunshades · Friar Center at Providence College
Figure 22 · Facade-to-roof transition · 525 William Penn. Place
Figure 23 · Installation Sequence
Interested in learning more about what Innovation Glass can offer?
ABOUT THE AUTHOR
FRANZ SAFFORD, FACADE ENGINEER
CEO of INNOVATION GLASS
Expert in all aspects of curtain wall construction process, from initial conception/design development, engineering, material selection, fabrication, project management and installation. Read Full Bio →