Architectural Record BE - Building Enclosure

A Plant Tour: Single-Source Glass Fabrication

Architectural glass offers a range of aesthetics, performance attributes, and size limitations critical to successful building design
This course is no longer active
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Sponsored by Viracon
C.C. Sullivan
Continuing Education

Learning Objectives - After this course, you should be able to:

  1. Define single-source fabrication and its impact in relation to architectural glass performance, appearance, warranty, and energy efficiency or sustainability attributes.
  2. Explain two or more fabrication technologies for producing glass units, such as laminated and insulating glass units, and their impact on building energy performance and occupant comfort and health.
  3. Describe one or more fabrication processes that limit the size of glass units.
  4. List at least two components in insulating glass units, and their impact on green building design.


1 GBCI CE Hour

Understanding fabrication and manufacturing improves any architect's knowledge and ability to design better buildings. In this educational article, a focus on the fabrication of glass enclosure systems provides architects and design teams with a helpful understanding of the processes involved and how they allow for specification and erection of buildings incorporating insulating glass units (IGUs) or other glazed assemblies.

An important distinction to make first is how to distinguish single-source fabrication as opposed to multiple-source fabrication in relation to complex products like architectural glass units. Simply put, with single-source production all of the processes are completed for the building product or system “inside the fence” of a plant operated by one legal entity. Following the production of the base material —float glass, for example—all the finishing, assembly, testing, and packing for the product and any related components are handled by that one fabricator. The same fabricator will typically provide both technical and design assistance to architects, glazing contractors, and glazing consultants to ensure the glass products meet the design intent. The finished item is generally warranted by one entity also.

This practice of single-source fabrication has two senses: In supply-chain management, original equipment manufacturers (OEMs) provide components to a final manufacturer or fabricator, who assembles and prepares the marketable item with OEM-made subcomponents. In the architecture field, the focus is on discrete and often important assemblies, such as the insulating glass unit, where performance and accountability are seen as critical to finished building performance.

Single-source fabrication delivers valuable benefits to the construction team. “Why single source?” asks Peter Dawson, a consultant and supply chain expert. “The pros are consistency and single-channel management.” That means rigor and accountability to the building team, for one, as well as schedule and budget control by one vendor, which many corporate and institutional owners prefer. The main drawbacks, Dawson cautions, are summarized as “supply-side disruptions.” For example, if there is a natural disaster that affects a project supplier, it would be preferable to have two suppliers at the ready—with matching products, meeting all specifications and ready to deliver—in the event of an unforeseen delay.1

Lanyang Museum

Photo © Lo Jui-Chin, courtesy of Viracon

Lanyang Museum
Location: Yilan County, Taiwan
Architect: Artech Architects

This works well in the manufacturing realm, but in building construction where most products are “made to spec,” the trend has been to limit the number of suppliers as a strategy to prevent project interruptions and delays.

“The use of a single-source supplier has benefits across the architectural value chain,” says Kevin Anez, director of marketing and product management at Viracon, a glass fabricator. The value chain for fenestration and glass envelope systems is defined as all project stakeholders, beginning with the owner or real estate developer and its design team—architect, engineers, and façade consultant, for example—as well as the involved construction team and glazing subcontractor and, not least, the fabricators and manufacturers.

In this way, the architectural glass value chain extends to primary glass suppliers who operate float glass plants, for example, and regional glass fabricators, which cut, temper, coat, and finish the glass and assemble it into final, installation-ready products, Anez explains. There are also commercial glass fabricators of national and international scale, which provide the same types of services and hold a relatively large market share.

Savvy architects and owners who build frequently favor a single supplier or manufacturer for building systems where quality is important or where performance is essential—or both. The number one sourcing benefit and architectural concern is quality control, though reduced coordination among building product manufacturers (BPMs) is a benefit in both the design and construction phases. In addition, simplifying the supply base can help reduce transportation costs, which cuts energy use in the construction phase.

Inside a glass fabricator facility in Owatonna, Minnesota, an interlayer is applied during the laminating glass process.

Photo © Brian Savage, courtesy of Viracon

Inside a glass fabricator facility in Owatonna, Minnesota, an interlayer is applied during the laminating glass process.


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Originally published in Architectural Record