Fire-Rated Glass Offers Clarity

Architects Push for Aesthetic Improvements over Compromise

By Jordan Scott

“We run into issues with fire-rated glass as architects. It comes down to the visual appearance of the glass,” says Christoph Timm, associate director at Skidmore, Owings & Merrill.

Technology improvements are making fire-rated glass safer, clearer and more color-neutral than ever. Yet architects such as Timm see the glass as a major tool for increased safety measures in buildings. Their desire for innovation rather than compromise is pushing the boundaries of fire-rated glass technology.

Fire-Rated Innovation

“It has been our experience that the architectural community has really embraced incorporating fire-[rated] glass and framing into their designs,” says Tim Nass, vice president of sales at Safti First. “Honestly, it has been the architectural community that has driven much of the innovation in our market segment. Designers continue to push the boundaries of what is possible. They are excited to express their vision through our products and are eager to see it become a reality.”

In the past five years, Safti First has introduced larger lites, blast-rated systems and butt-glazed glass without intermediate verticals.

“All of that because a building had a need for a multi-functional, rated scope of work. Many of the systems were in research and development, but projects made them a reality,” says Nass.

Technological advances have improved the aesthetic value of fire-rated glass according to Scott Fox, district sales manager at Vetrotech Saint-Gobain North America.

“Due to the molecular makeup of the ceramic, ceramic glass inherently has somewhat of an orange tint or amber hue. Due to advanced manufacturing techniques, this has become less and less of an issue compared to several years back,” he says. “The appearance of color through glass is measured with the color rendering index (CRI). To-day’s polished glass ceramic products can offer a color rendering of 97.1. This is very close to fl oat glass that typically has a CRI that measures around 98.8.”

Many architects associate fire-rated glazing with wire or ceramic glass.

“While those products are functional, they lacked flexibility and appeal from an aesthetic perspective. Bill O’Keeffe, founder and CEO of Safti First, has al-ways championed the use of tempered glass in its rated, code-driven products,” says Nass. “Because our products are listed in [the Construction Specification Institute’s MasterFormat] Division 8 [the doors and windows division of the standard], people forget we are actually providing a transparent barrier. Even though you can see through it, by code it is considered an extension of the wall compartmentalizing the visual elements of a fire as well as reducing the transfer of radiant heat.”

According to Dave Vermeulen, national sales manager of Technical Glass Products, framing has made a huge difference in the color of fire-rated glass.

“When there’s no light refracting through the edge of the glass, the hue disappears. When the edges are captured, the glass looks clearer. That’s why samples tend to look less color-neutral than the final product,” he says. “Years ago, less than 1 percent of glass going into a project was fire-rated. Now you’re seeing more fire-rated stairwells and large, fire-resistant openings. Framing solutions are also starting to match the aesthetic of non-fire-rated frames.”

The initial turn of fire-rated glass was when ceramics became prevalent, according to Vermeulen.

“The glass lost its visual nuance with wired glass. It made the push toward safety into a push toward safety and aesthetics,” he says. “Ceramic glass has a zero rate of contraction and expansion. It can be hit with high heat then hit with water and it responds positively to the thermal shock.”

Pushing the Envelope

Color clarity is also better thanks to improvements in the ceramic material ingredients and raw materials, but for Timm, ceramic glass is not the ideal solution.

“Use of regular float glass is preferred—the interlayer being fire-rated material rather than ceramic glass being [what stops the fire] if possible. Often times the colors don’t look the way we expected—they have a brown or green hue.”

Timm continues, “Traditionally, curtainwalls don’t use fire-rated glass. At least I’ve never used it. However, I’ve seen examples of … fire-rated curtainwall that blends in with the rest of the wall,” he says. “It would be ideal economically and for daylighting if we used two-hour fire-rated glass behind the curtainwall. It could be used more extensively for curtainwall in the future, absolutely, but it comes at a price. Combining it into the exterior skin would be fantastic.”

According to Fox, with the increased use of daylighting in design, architects’ main concern is how large the fi re-rated glass can be made and still be certified for performance.

“We have our own in-house testing facilities that date back to 1996 with more than 4,000 tests done and counting. We often meet a project’s unique fire-rated needs where [another] fire-rated product might not have existed due to size or duration restraints,” he says.

Future of Fire-Rated Glass

Despite the limitations, Timm sees the fire-rated glass market growing due to the need for increased safety measures. He prefers fire-resistive glass, which defends against the spread of fire and protects from radiant and conductive heat, to fi re-protective glass, which prevents the spread of flames and smoke.

“It’s important for architects to understand the difference in products. The chances are that the ignition point of an interior space temperature will get so hot that fire will be started by the sheer heat load. That’s why it’s important to use fire-resistive glass,” he says.

Fox says that architects look at the cost-benefit ratio, not only from the point of acquisition but how a product will perform during an incident. Fire-resistive products keep “a fire condition compartmentalized within the room that it starts.”

If the room is next to an egress hall-way, this allows for safe passage of occupants out of the building.

According to Nass, the future of fire-rated glass technology is a focus on further multi-functionality.

“Many of our applications require what we would consider ancillary performance requirements such as security, sound attenuation, impact and the list goes on,” he says. “As the codes evolve and our products are incorporated into the building envelope, the demands on our product increase exponentially. Much of the innovation is driven by design and the desire to try things that have never been done before. Rated products are no longer given an exemption relative to performance, and I believe that is a positive for our industry and the market.”

To view the laid-in version of this article in our digital edition, CLICK HERE.

This entry was posted in Uncategorized. Bookmark the permalink.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.