Architectural Glass Mutates As Building Teams Innovate Courtesy Enclos Courtesy

| GLASS + GLAZING INNOVATIONS |

ARCHITECTURAL GLASS MUTATES AS BUILDING TEAMS INNOVATE COURTESY ENCLOS COURTESY

Project teams Author info are using technologies like digital ceramic printing to incorporate graphic patterns and imagery in glass panels.

ovel concepts in glass and concluding that a “lack of qualified skilled LEARNING OBJECTIVES glazing are opening new vistas workers was by far the largest concern for After reading this article, in the buildings world. From glazing contractors entering 2019.” you should be able to: massive openings and bent Product availability has been hampered + DISCUSS cold-bent glass versus panels to decorative finishes in a few cases by international trade heat-treated glass forming. and integrated smart technolo- tariffs. The first step in inventive glass de- + DESCRIBE the challenges of large glass gies, a cornucopia of glass in- sign strategies is to ensure the products, openings. novations have been hitting the market in fabricators, and glaziers are available to + LIST techniques for silk-screening and Nrecent years. A review of new projects and meet the plan requirements and fulfill the spandrel treatments. recent product introductions gives an idea delivery order. + DESCRIBE the use of films, coatings, of the astounding range—and a few key For those touring factories or attend- and fritting. lessons to live by—in today’s institutional ing the major glass expos, one answer to and commercial sectors. the shortages is seen in the increasingly In many geographies, however, frustrated automated operations in float glass plants Sponsored by building teams also face shortages of and finishing operations. At the shows skilled specialty contractors and glaziers to glasstec and GlassBuild, as well as Fin- help build their visions. The U.S. Glass News land’s Glass Performance Days, present- Network has reported on its own studies ers have demonstrated sealing robots and

54 | BUILDING DESIGN+CONSTRUCTION | November 2019 new automated machines for insulating and lami- nating panels and air-cushion tempering, as well as EDMON LEONG systems for faster processing of glass edges. Advantages for building teams include faster and more reliable processing of bent glass (and curved glass), a fast-growing trend in recent years. “While this technology has been around for some time, recent advancements now enable larger and more complex bent shapes to be created,” according to the fabricator Dillmeier Glass Co. “This has expand- ed its uses, and driven increased demand, including for glass railings, awnings, and even walls.” Early examples include Frank Gehry’s Nationale- Nederlanden Building in Prague, with its tower of curved glass, as well as the Kunsthaus Graz museum in Austria. More recently, the 3,000-plus cold- Increased demand for trans- bent and laminated panels made of safety glass parency, views, and daylight for Apple’s headquarters in Cupertino, Calif., were has led to the fabrication of designed by architect Foster and Partners alongside monolithic glass panels in sizes previously unseen. The the German maker Seele and its subsidiary fabrica- new 53W53 project in New tor, Sedak. Sedak manufactured 872 cold-bent York City features a diagrid laminates constructed out of two large-scale panes, façade with glass units up to 28.5 feet tall by about including insulated safety glass. 7 feet in width. Unlike conventional sag bending or slumping using heat to soften the panels, cold-bent glass turns flat plates into curved shapes at ambient to laminated glass using temperatures, and the process can be completed polyvinyl butyral (PVB) after the glass is tempered. Some manufactur- interlayers. Using less heat ers are even cold-bending insulated glazing units than an oven, the laminated (IGUs) with good results, as used in commercial panels help each other hold structures such as the IAC Headquarters in New the designed shape, with York, designed by Gehry Partners and built by the ionomer layer up to 100 Turner Construction. times stiffer than PVB. Con- Cold-bending techniques push flat glass into a tractors note the preshaped frame for the desired bending. The heating ap- panels can be easier to in- proaches generally have been more expensive, stall, and some assemblies employing molds and large tempering ovens or kilns can be completed at the to fashion the desired bends and curves, yet the plant to speed construction, processes are equally reliable. However, experts with seals and railings ready for sitework, according note that for double curvatures, sharp bends, and to Sedak, which has introduced new lamination bend right angles, heating is the best specification. Many processes in recent years. fabricators have adjustable bending ovens that no longer require molds, instead using moveable sec- LARGE GLASS OPENINGS tions to customize the bed for the designed shape. Another obstacle trending in recent years has Cold bending has limits in terms of shaping glass been increasing end-user demand for larger glass and may also introduce undesirable optical and openings requiring expensive monolithic panels in reflective qualities in the installed product. sizes previously unseen. These are being applied Another approach to shaping panels, called to a range of building types and market sectors, lamination bending, employs a pressurized autoclave including for interior partitions, according to the to sandwich heat-strengthened panels to ionoplast fabricator Dillmeier, based in Van Buren, Ark. Very interlayers, which studies show can improve struc- large architectural units have been used in recent tural properties and weather resistance as compared projects in sizes up to 11 feet wide and 20 feet

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including trapezoidal modules and large units up to An emerging decorative technique 28.5 feet tall by about 7 feet in width, according to 3M VIA ARCHITONIC is the application of multilayered the façade consultant Vidaris and the curtain wall polymeric films, often called dichroic filters. The polymeric films selec- maker Enclos. tively admit light in a small range of “Installing large units in the middle of Manhattan colors while reflecting other colors, at such great heights in front of a unique structure appearing to be highly saturated with color that shifts depending on have required several equipment innovations that the viewing angle. continue to aid the field crews in safe installation,” according to Enclos. Other challenges for projects like these include “heightened acoustical perfor- high. Total areas of more than 200 sf mance, and combinations of geometric complexity are now commonly specified for both and transparency,” says Jeffrey Vaglio, PhD, PE, AIA, interior and exterior uses. LEED AP, Vice President of the Enclos Advanced Recent examples include the new Technology Studio. “More projects are incorporat- 53W53 project in New York City, ing curved glass, double-skin façade box-window designed by Adamson Associates, systems, and more use of terra cotta features Ateliers Jean Nouvel, SLCE Architects, integrated into the curtain wall system.” and engineer WSP USA for a Hines Yet, it’s the improving economics of large glass subsidiary developer. Located by the opening that make them feasible today, according Museum of Modern Art, the building’s to Brian Savage, a Product Manager with Viracon, lower floors add 52,000 sf of exhibition space for who concluded in a recent white paper, “The op- the cultural institution behind an oversize motorized portunity to incorporate these bigger glass units door measuring 34 feet by 17 feet 8 inches. Above into the design of buildings with minimal overall that, a diagrid façade presents unique glass units investment is driving the trend from the east and

CITIES ADVANCE CODES—AND GLASS SAFETY

n In municipalities around in 70 years. ties that lag the rest of the of fire-rated glazing should the country, building teams What’s behind the drive country in code adoption will be used for the application are watching carefully as toward the 2018 IBC is an ultimately pay in terms of the because it is clearly outlined authorities having jurisdiction increased focus on safety, in- health, safety, and welfare of in these tables,” said Diana (AHJs) adopt the latest Inter- cluding glass systems safety. the public, of businesses, of San Diego, Vice President of national Building Code, its “These guidelines,” accord- visitors, and of the commu- Marketing at SaftiFirst, in a 2018 iteration, in major building to Milrose, “encompass nity’s future vitality,” NIBS said USGlass Magazine interview. ing markets, from Chicago to numerous structural design in a joint statement with other In addition to these safety New York State. best practices meant to pro- federal agencies. improvements, the Interna- New York is adopting the mote quality commercial and As an example, the 2018 tional Code Council (ICC) has 2018 I-Codes this fall, ac- residential development and IBC safety changes include shown how I-Code adoptions cording to Josh Breeden of thereby ensure tenant health recognition of two types of also make construction more Milrose Consultants, describ- and safety.” fire-rated glass referenced in affordable. “The new code ing its transition period of A study by the National Chapter 7: fire-protection and represents the first compre- approximately 90 days and Institute of Building Sciences fire-resistance glass. The IBC hensive revisions to the build- a mandatory effective date (NIBS) on natural hazard miti- also defines where those safe- ing code in 70 years and will after January 2020. Chicago gation looked at the benefits ty glass types may be used make construction in Chicago adopted the 2018 IBC in April of designing buildings to meet and any related limitations. more affordable by expanding of this year, which experts the 2018 IBC and found major “Moving forward, there should options to design and build describe as a major change advantages: For every dollar be less confusion among with a wider range of materi- for a city where no major code invested, localities receive architects, building officials, als and technologies,” the updates have been embraced $11 of benefit. “Communi- and end-users on what types ICC said.

56 | BUILDING DESIGN+CONSTRUCTION | November 2019 west coasts onto buildings throughout the country.” Presenting a representative building example,

Savage calculates that 100,000 sf of glass in RUNCORN GLASS & GLAZING COMPANY standard-size glass will account for about 1.7% of the entire project cost. Using large glass sizes for 5,000 sf of the façade, such as for an atrium, increases the glass cost minimally to about 1.8% of the entire project. If all 100,000 sf were made with large-size units, adds Savage, the glass bill would be about 3.2% of the total. The partial façade areas with large unit sizes is a common approach, according to Saint Gobain installed by Seele. Color-neutral glass units Building Glass. For the rebuilt World Trade Center’s measuring 7 feet 10 inches wide and more than Recent innovations in sculptural subway station building in New York, Span- 25 feet high installed at ground floor locations glass fabrication include ish architect Santiago Calatrava and the project team span from the floor to the ceiling. Detailed without faster and more reliable processing of curved selected oversized glass panels for the entrance any cross-section and with profileless vertical glass. Advancements area, with unit sizes reaching 25 feet 6 inches by joints, the glass enclosures are practically enable larger and more 2 feet 8 inches between the structure’s girders. invisible, heightening the effect of the voids. complex bent shapes to be created for glass railings, Complementing the total area of about 43,000 sf of With market demand for large glass expo- awnings, and walls. highly transparent, extra-clear glazing with a custom sures, many buildings are using structural glass solar-control coating, the 800 extra-clear glass panes or frameless assembly systems, which do not provide an identical visual appearance. encounter the same limits in unit size and weight. Another example is The Broad Museum in Los They do tend to be costly, however, and require Angeles, designed by Diller Scofidio + Renfro and extensive structural engineering work and rigor-

ACHIEVING UNOBSTRUCTED VIEWS IN 2-HOUR ATRIUM WALLS

There is a growing trend in office space design that favors increased opportunities for connectivity through face-to-face encounters among its occupants. In buildings with multiple floors, one way to achieve this is by incorporating an atrium, where part of the central floor section is removed. This is what the architects designing new office spaces for one of the world’s leading tech corporations did. At the heart of the building is an atrium connecting the 6th to the 8th floor, allowing daylight and visual connections from different work spaces. To meet code requirements while providing unobstructed, floor-to-ceiling views, SAFTI FIRST supplied a 2-hour fire resistive butt-glazed wall assembly using ASTM E-119/UL 263-rated SuperLite II-XLB 120 in GPX Architectural Series The result is a beautiful, light-filled atrium offering maximum views and WWW.SAFTI.COM perimeter framing. reliable, 24/7 fire protection. CIRCLE 770

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tally benign and the materials can be recycled at the end of its useful life, according to LEED- COURTESY SAFTI FIRST COURTESY accredited Cathie Saroka, President and CEO of Goldray Industries, Inc. The highly durable ceramic ink is specified in laminated or monolithic form to create printed designs often in combi- nation with a high-performance, low-emissivity glass, “used as a way of controlling solar heat gain into the building.” Ceramic printed glass is often combined with backpainting or laminat- ing, providing greater design flexibility or more customized solutions. Another decorative technique making headway in the commercial and institutional markets is the application of multilayered polymeric films, often called dichroic or interference filters, such as those made by 3M. Applied to building glazings, typically laminated between two or more glass lites, the polymeric films selectively admit light in a small range of colors while reflecting ously made attachment systems. In both cases, other colors, appearing to be highly saturated the very large glass panels or structural glazings with color that shifts depending on viewing An application that makes buildings more tend to be used in smaller areas and specialized angle. Combining the films, available in both adaptable and respon- applications for architectural effect. At Apple’s opaque and translucent versions, with textured sive is fire-resistive headquarters, for example, the largest exterior or acid-etched glass panels can enhance or glass, which increases the available and code- window panels measure around 47 feet long by mute their optical effects. Last, more project allowable area of glass 10 feet tall, a precedent for large panel window teams are employing metallic finishes on glazed enclosures. The adoption fabrication. Interior panels along the facility’s surfaces, echoing the use of metallic finishes in of the latest Interna- tional Building Code central courtyard reach 36 feet in length. other building materials. New laminated metal (IBC), the 2018 iteration, mesh glass products, for example, are used to provides enhanced detail MORE COMPLEX AND DECORATIVE give glass an appearance of aluminum, gold, on the limitations of fire-protective glass. Size is only one dimension driving glass use or copper weave, with benefits for controlling today. Another is finish and appearance. For daylighting and solar gain. the very large monolithic glass products, for example, some building teams are using HIGH-TECH GLASS PERFORMANCE silk-screening and spandrel treatments, as well Treating glass façades as more of a filter is one as substrates and special coatings for aes- of the key design trends for today, says Craig thetic variation. Schwitter, PE, Partner at BuroHappold Engi- The finishes are becoming more decorative and neering. “The results are less like structures thus more complicated and expensive, according and more like filters,” says Schwitter. “They to Dillmeier: “Along with larger lites, architects are balancing the exterior climate and interior and designers are calling for more decorative climate to make the interior spaces habitable, glass, too. This includes panes with patterns, de- enjoyable, and inspiring.” signs, colors, or textures added, to create a more The technology that makes this possible is a ornamental finish.” Using technologies including culmination of advances in modeling technology digital ceramic printing, building teams are able and computer-aided manufacturing, Schwitter to easily incorporate graphic patterns and high- adds, which can result in low-energy and high- resolution imagery in glass panels. performance buildings. Other breakthroughs Not unlike inkjet printing on paper, the highly in glass technology provide for tunable perfor- automated digital printing techniques directly mance based on the needs of the “environmen- depose ceramic inks on glass surfaces, creat- tal filter” and changes in weather and other ing abrasion-resistant and colorful patterning. In external factors. Switchable privacy glass, an addition, digital ceramic printing is environmen- increasingly popular specification, employs

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low-voltage electrical current to arrange liquid (IBC), the 2018 iteration, provides enhanced crystal molecules into patterns that make glass detail on the limitations of fire-protective glass, Bird-safe glass on skyway. sheets transparent, according to Guardian such as wired glass and ceramics, which are Glass, which manufacturers a switchable prod- rated up to 90 minutes and 180 minutes uct. “Turned off, the liquid crystal molecules respectively yet must be limited to 100 square revert to a random pattern, diffusing the light inches in area even when the building is fully and causing the glass to become opaque,” the sprinklered (see sidebar on page 56). company explains, adding that the glass instal- To exceed that code-maximum area, applica- lations can be controlled with a switch, motion tions of fire-resistive glass—also known as fire- detector, daylight sensor, or another device. resistance glass—are specified with IBC’s refer- Recent technological improvements have im- ence criteria given in the fire-testing standard proved the quality of switchable glazings while ASTM E-119, “Standard Methods for Fire Tests cutting product costs, according to the blog of Building Construction and Materials,” as well GlassOnWeb.com. Novel switchable films pro- as UL 263, “Fire Tests of Building Construction vide a low-energy alternative, with greater clarity and Materials.” Both standards are typically when energized as compared to previous gener- used to test construction assemblies such as ations of films. Popularized by glass conference floors, enclosures, walls, ceilings and other rooms and healthcare applications, according to structural elements. the fabricator Dillmeier, “It can also be incorpo- Similar to fire-protective glass, the resistive rated into traditional glass applications, such type can be used to compartmentalize smoke as room partitions and doors, or less common- and flames, yet the fire-resistive glazing addi- ly, even countertops and furniture.” tionally can be used to block the transmission Another application that makes buildings of radiant heat. Radiant heat is a significant more adaptable and responsive is fire resistive concern during building fires. It can cause harm glass, which increases the available and code- to building occupants within 20 feet of a glass allowable area of glass enclosures. The adop- partition separating them from the fire source, tion of the latest International Building Code and can also ignite combustible materials on the

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non-fire side of the glass. Matched with proper ska USA, about one-third of the building’s 9,500 framing, “Fire-resistive glass can save lives with- sf of window glazing from ground level to about out compromising an architect’s design vision,” 30 feet above grade is treated with a dot matrix according to former fire marshal Robert David- of ceramic fritting. The simple frit specifica- son, by effectively compartmentalizing smoke, tion—which added about $32,000 to the cost flames and radiant heat to provide safe egres of the project, according to The Kendeda Fund— regardless of the size of the glazed area. employs a silk screening process to create the grey dot patterns. A recent study by Pow- GREENER, SAFER GLAZING dermill Nature Reserve employed a specially Another safety focus for glazing specifications constructed tunnel to observe how various bird relates not to human occupants but rather to species responded to different kinds of glass nearby birds. With hundreds of millions of birds intended to reduce collisions from at least 20 lost due to collisions with buildings—and more glass fabricators. About 94% of the birds tested than half involving low-rise and midrise struc- fly toward conventional glass openings when tures of four to 11 stories tall—building teams side-by-side with ceramic fritted glazing. The are studying the effectiveness of varied solu- results showed that dark gray bands of fritting tions. Examples of retrofit products include cur- were the most effective at discouraging birds tains of fine nylon monofilament lines, adhesive from flying toward the windows. A few cities and dots and decals, and safety films, as well as states, including San Francisco and Minnesota, an acrylic Plexiglas with embedded polyamide have adopted bird-safe building standards, and threads for handrails and noise barriers. federal legislation has been proposed. In the For new buildings, a variety of films and meantime, the U.S. Green Building Council has fritting as well as architectural enhancements introduced a pilot credit for the design strategy can be used. Georgia Tech’s Kendeda Building into its LEED certification program, an influen- for Innovative Sustainable Design in Atlanta, tial standard. “It is one of the few resources designed to meet Living Building Challenge out there that suggests strategies for avoiding certification, employs bird-safe glass to enclose bird collisions,” according to Georgia Tech’s its education, research, and outreach facilities. Kendeda Building design team leader, Joshua Conceived by Lord Aeck Sargent and The Miller Gassman, R.A., LEED AP, Director of Sustain- Hull Partnership with general contractor Skan- able Design for Lord Aeck Sargent.+

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