Compare and Contrast: Differences in Overhead vs. Vertical Dynamic Glazing Installations

The Dynamic Glass Act of 2021 was introduced in Congress earlier this year. If passed, it will amend the Internal Revenue Code of 1986 to allow the energy investment tax credit for electrochromic glass. The goal is to incentivize businesses to invest in dynamic glazing technology for its energy-saving benefits. While no movement has been made on the bill, its introduction shows an increased awareness in dynamic glazing, which could lead to adoption in the future.

As dynamic glass, or smart glass, continues to be specified, glaziers need to be aware of installation differences in overhead vs. vertical applications, as well as general best practices.

Dynamic Differences

Overhead dynamic IGUs typically are thicker and heavier for two reasons: the system must accommodate snowloads and the inboard lite must be laminated to meet safety glazing code requirements. Greg Brown, project team manager in field operations for SageGlass of Faribault, Minn., says the thickness difference is minimal. Typical vertical dynamic IGUs from SageGlass are 1-inch thick and typical overhead dynamic IGUs are 1 3/8-inch thick.

The height and positioning of overhead dynamic glazing requires different rigging compared to vertical applications. Brown points out that a crane is often used for dynamic skylight installations whereas scaffolding may be used for vertical applications.

Wiring is another important consideration.

“The wires, or what we call frame cables, might be longer for skylights because typically the glazing contractor will root those wires down to the bottom edge of the skylight to get it inside the building,” says Brown.

Tyler Hall, business development manager for Denison Glass & Mirror Inc., in Denison, Texas, says overhead dynamic glazing projects may require creative solutions. In one recent project, his team had to work with the manufacturer and electrician to bring the terminal boxes closer to the skylight.

“The skylight’s sheer size and the fact that it’s hanging over a large, open space makes it challenging,” says Hall, who adds that splicing the wiring would likely result in too much power loss to work.

Vertical applications usually are close to a wall component. Hall says it’s rare to have a large, continuous curtainwall that doesn’t allow a tie-back area or spandrel for the wiring. When installing overhead dynamic glazing, Hall says it’s important to look at the nuances of the system, since different manufacturers use different methods to shed water and ensure water and weather tightness. He says some systems may have a member running through the extrusion so it’s difficult to put a hole there to run the wiring.

“The single biggest differentiator is to make sure to adhere to the water tightness and weather tightness requirements,” says Hall.

Smart Practices

For both overhead and vertical installations, it’s important to ensure the wires are neither pinched nor cut, says Brown. He recommends glaziers protect and watch the wires no matter the application. Brown suggests following installation guidelines from industry associations for both application types. SageGlass offers training and guidance to field teams to ensure the glazing contractor understands how to approach the installation no matter the application.

Hall recommends that glazing contractors plan and prepare for the installation well in advance, including how many glaziers are needed, their experience, the type of equipment needed and how to install the glass safely. He stresses the importance of partnering with a low-voltage contractor early on to ensure all needs are considered and the installation is successful.

Jordan Scott is a contributing writer for USGlass magazine.

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