Ensuring sufficient fenestration selection for a competitive high-performance market
This month’s blog focuses on the fourth concept in the Façade Tectonics Institute’s (FTI) blueprint for market transformation of façade performance: ensuring a sufficient selection of high-performance curtainwall and window wall systems and trained installers is available for a competitive market.
During FTI’s research for their market barriers report to the U.S. Department of Energy (DOE), stakeholders from markets where building codes are more stringent (Massachusetts, British Columbia, Washington State) reported that there are not enough curtainwall or window wall options with the needed performance to create a competitive market. Many installers are not familiar with the few existing high-performance systems. That unfamiliarity adds a “newness” premium to the already higher cost. As a result, they told us that higher-performance systems are value-engineered out of the design.
FTI also reported that curtainwall performance “has fallen significantly behind the market’s needs where code stringency is highest,” such as in Massachusetts and British Columbia. Curtainwall performance must get closer to opaque wall performance, especially in the opaque spandrel areas. Spandrel suffers significantly from thermal bridging around the insulation in the spandrel assemblies and up and down the continuous vertical mullions that allow heat to flow unhindered between transparent and opaque elements.
Will Curtainwall Lose Its Coveted Place?
In contrast, participants pointed to how Europe has evolved to using precast concrete, glass fiber reinforced concrete (GFRC) and ultra-high-performance concrete (UHPC) in mega-panel systems complete with integrated fenestration. These systems have displaced many traditional unitized curtainwalls because they meet the increased performance needed. Also, the ability to unitize the GFRC and UHPC technology has addressed the “easy-to-install” advantage that curtainwalls have previously held as the go-to cost-effective wall system for many decades.
Solutions for High-Performance Curtainwall Designs
To prevent replacement by precast panels, fenestration fabricators must address the widening performance gap between current business as usual and what is needed in the highest-performance markets.
Solutions are not beyond reach. The figure above shows a series of options for using polyamide (PA) thermal barriers to improve the thermal performance of captured and structurally glazed curtainwall systems. A PA pressure plate and wide dual thermal barriers reduce conduction. Foam filling between the thermal barriers reduces convection (A). PA glass edge adapters reduce conduction and compartmentalize cavities to reduce convection in a structurally glazed curtainwall (B).
In spandrel assemblies, triple insulating glass units (IGU) are essential, along with maximized insulation behind the glass. Deep thermal barriers, foam filling and PA pressure plates are also critical for captured spandrels (C). In all cases, a warm-edge spacer, such as a plastic hybrid stainless steel box spacer, is critical for reducing thermal conduction at the edge of the glass.
Blueprint Solutions
The blueprint proposed three connected solutions to deliver more cost-effective curtainwall and window wall solutions.
1. Implement a prize program for high-performance curtainwall and window wall
As a benchmark, an award program run by British Columbia gave relatively small prizes of up to $40,000 per product line to several companies to develop and test high-performance fenestration products. This program, funded with only a modest $500,000, created a critical mass of products to support more stringent code implementation. FTI suggested DOE could fund and deploy a similar program in the U.S. to incentivize a range of manufacturers to bring products to the market by reducing critical investment costs. DOE recently awarded a similar prize program for secondary window systems.
2. Create a research and development collaborative program to develop and deploy the next-generation of façade systems
The creation of a broad collaborative/network of academics, practitioners and industry partners could create a critical mass of multidisciplinary knowledge and capability to develop high-performance facade systems, train installers and engineers and disseminate information. Such a program could be modeled on the European program for an Adaptive Façade Network funded by the European Cooperation in Science and Technology (COST) between 2014 and 2018. In this instance, FTI’s concept was that the collaborative would be North American-focused, with participants from across the full design-build spectrum and building code developers and enforcers. It would leverage National Laboratory capabilities and university research groups focused on façade engineering.
3. Develop and deploy an installer-training program for high-performance systems.
Since installer familiarity with new fenestration systems can impact the quoted cost, installers must become familiar with installing new high-performance systems. Training programs must address how to manage the interfaces between fenestration and the wall to ensure the continuity of the air/water/vapor barrier and mitigate thermal bridging. Training could also reduce the risk of installers providing lower-performing substitutions or no-bids.
The Architectural Glass and Metal Certification Council (AGMCC), which operates the North American Contractor Certification (NACC) and the Architectural Glass and Metal Technician Certification programs, could be an ideal collaborative organization. AGMCC may even be able to incorporate such content into its existing programs. Building capacity in the installer base is critical in eliminating the barrier between product innovation and field deployment.
Impact of More High-Performance Curtainwall Systems and Higher Installer Capacity
Providing sufficient high-performance window wall and curtainwall systems offered by fabricators would address several barriers to adoption:
- Requests from design teams to have three equivalent solutions often hamper the adoption of high-performance systems because of the risk of price gouging if a proprietary product is specified.
- Creating needed competition would reduce market prices, therefore improving return-on-investment assessments. By reducing market prices, adoption rates would increase, allowing economies of scale to be captured in manufacturing, further reducing market pricing.
- Ultimately, this virtuous cycle will support faster code stringency increases because the cost-effectiveness could be easily demonstrated.
As Mic Patterson commented last month, the report Steve Selkowitz and I wrote for DOE on the barriers to high-performance façades “is the gift that keeps on giving.”
The 100-page report has a considerable amount of broad content, touching all participants in the design-fabrication-materials-installation-code-code enforcement-education ecosystem. It is critical to socialize the findings widely to enable the needed change. Since 100 pages are a lot to read in one sitting, I have been stepping through the conclusions of this blog over the past year, breaking the content down into smaller, more easily digestible chunks.
Next month, we will examine the fifth concept in FTI’s blueprint—certification programs for a range of practitioners.