What does the next generation of facades look like? This was a question discussed at the first session of the Building Envelope Contractors (BEC) conference in Nashville, hosted by the National Glass Association. Brandon Andow, Principal Building Performance Analyst and Associate Director at EYP, an integrated design firm, discussed some of the product and technology changes and developments that will shape the design and construction of building facades.
He started with a look at dynamic glazing systems. While electrochromic glass was the forerunner, there are other technologies, such as liquid crystals. The electrochromic glass has been specifically developed to meet the potential of natural lighting. He noted that the promise of dynamic daylighting is to turn off electric lights and control visual comfort. However, glare is still an issue, so electrochromic glazing isn’t necessarily going to bankrupt the blind industry, he noted.
Andow also discussed closed cavity facades (CCFs). The CCF is a double-skin closed facade, double or triple glazing on the inside and single glazing on the outside. Double-skin facades have been around for a long time, but as Andow said, many are still hesitant to figure out the best way to optimize these systems. With a CCF, blinds can be installed with the cavity to protect them while blocking the sun. CCFs also help improve thermal performance, increase the window to wall ratio and can improve acoustics.
Another product area the industry may see more of in the future is panel wall systems. Andow says he thinks there will be increased focus on opaque assemblies, including more panel wall systems and more design options with terracotta, brick, etc.
Looking to the future, Andow explained where the industry needs to design when it comes to technologies. Envelope systems, he said, must meet changing and often conflicting requirements. This includes, for example, attenuation or promotion of light transmission for daytime use and control of heat transmission or absorption for thermal comfort and heat load reduction. Further, he said envelope systems should manage the direction and intensity of light for visual comfort and productivity and promote the appropriate distribution of the visible spectrum at the appropriate time of day for human physiology and the circadian entertainment. All of this, he said, must be done while co-managing privacy with outward views and achieving the main design element.
With this in mind, he then went on to discuss various considerations that can impact the glazing and facade. This included several areas related to structural performance criteria. Andow said he expects changes and evolution as the climate becomes less predictable, including designing stresses and deviations due to greater variation in wind events. Impact, hurricane and wind-blown debris issues also lead to increased requirements. Airtightness of the entire building will also increase thermal performance.
He also discussed envelope safety net changes in ASHRAE 90.1-2022.
He said there’s “no limit to the gravity of your envelope”, if you balance that with more capable lighting and mechanical systems, for example. Safety nets will limit a design team’s ability to trade higher performing internal systems for an energy efficiency envelope in performance compliance lanes.
According to him, other considerations will continue to be important, including design for increased glare requirements; non-visual human systems (i.e. our circadian rhythms); and increased acoustic requirements.
He also mentioned that more construction proposals include plants inside the building. It will be essential to ensure that the plants inside continue to receive sufficient light.
“We spend money to put plants in the building, [so we need to] pay attention to how the light passes to ensure good lighting.
Speaking about the next generation of facades, he said it was also important to continue to tackle carbon emissions. As buildings become more energy efficient, embodied carbon becomes increasingly important. The concerns do not only relate to the production of aluminum and glass. He added that shipping and supply chain issues are also issues for embodied carbon.
The BEC Conference continues until tomorrow. Stay tuned to the USGNN™ for more news and updates from Nashville.