What does the next generation of facades look like? That was a question addressed during the first session of the Building Envelope Contractors (BEC) Conference in Nashville, organized by the National Glass Association. Brandon Andow, senior building performance analyst and associate principal with EYP, an integrated design firm, discussed some product and technology changes and developments shaping how building facades will be designed and constructed.
He began with a look at dynamic glazing systems. While electrochromic glass has been the frontrunner, there are other technologies, such as liquid crystal. Electrochromic glass was specifically developed to address daylighting potential. He noted the promise of dynamic daylighting is turning off electric lights and controlling visual comfort. However, glare is still an issue, so electrochromic glazing isn’t necessarily going to put the blind industry out of business, he noted.
Andow also discussed closed cavity facades (CCF). The CCF is an enclosed double-skin façade that is duel- or triple-glazed internally and single-glazed externally. Double-skin facades have been around for a long time, but as Andow said, many are still leery in figuring out how to optimize these systems best. With a CCF, blinds can be installed with the cavity to protect them and still block the sun. CCFs also help improve thermal performance, increase the window-to-wall ratio, and can improve acoustics.
Panel wall systems are another product area that the industry may see more of in the future. Andow says he thinks there will be an increased focus on opaque assemblies, including more panelized wall systems and more design options with terracotta, brick, etc.
Looking to the future, Andow discussed where the industry needs to be designing as far as technologies are concerned. Envelope systems, he said, must satisfy dynamically changing and often conflicting requirements. This includes, for example, mitigating or promoting the transmission of light for the day and controlling the transmission or absorption of heat for thermal comfort and thermal load reduction. In addition, he said envelope systems would need to manage the direction and intensity of light for visual comfort and productivity and promote the proper visible spectrum distribution at the appropriate time of day for human physiology and circadian entertainment. All of this, he said, must be done while co-managing privacy with views outside and achieving the primary design element.
With this in mind, he next addressed various considerations that could impact the glazing and the façade. This included several areas related to structural performance criteria. Andow said he expects changes and evolution as the climate becomes less predictable, including designing for stress and deflection due to more variation in wind events. Impact, hurricane and windborne debris concerns are also bringing increased requirements. The airtightness of the whole building will also increase thermal performance.
He also talked about envelope backstop changes in ASHRAE 90.1-2022.
He said there is “no limit to how bad your envelope can be,” if you balance that out with higher-performing lighting and mechanical systems, for example. Backstops will limit the ability of a design team to trade better performing internal systems for envelope energy efficiency in the performance compliance paths.
Other considerations he says will continue to be important include designing for increased glare requirements; human non-visual systems (i.e., our circadian rhythms); and increased acoustical requirements.
He also mentioned more building proposals include plants inside the building. It will be essential to ensure the plants inside continue to receive sufficient lighting.
“We’re spending money to put plants in the building, [so we need to] pay attention to how the light comes through to ensure proper lighting.”
Speaking of the next generation of facades, he said it’s also important to continue addressing carbon emissions. As buildings become more energy-efficient, embodied carbon becomes increasingly important. The concerns aren’t just with aluminum and glass production. He added that shipping and supply chain matters are also issues for embodied carbon.
The BEC Conference continues through tomorrow. Stay tuned to USGNN™ for more news and updates from Nashville.