Multi-Ply Glass

Multi-ply glass is a high-quality fiberglass sheet that contains multiple inner layers and/or plastic glazing for added protection to withstand extreme conditions, including forced entry, blasts, ballistics, hurricanes, and tornadoes. Like laminated glass, it can also provide enhanced acoustics, keeping sound in areas where appropriate and out where not. It can also provide daylighting options for secure areas that may not otherwise have the option for daylighting, like if the area were surrounded by a concrete wall for protection.

Image courtesy of National Glass Association

This image illustrates how multi-ply glass can contain various levels of insulating layers between glass lites for added security.

Whether it’s added protection or lower cost, there is a type of glazing for every application that provides benefits to the building owner. By specifying a combination of various glazing types for specific applications, architects and specifiers can create a solution that’s best for all.

Understanding Fire-Rated Glass and the Latest Trends

While protective glazing and security glazing that can frustrate intruders have become more popular in public places, fire-rated glazing products and fire-protective glass have been in demand for quite some time. Fire has been a risk to building structures for centuries, and market demand has driven innovative fire-protection technology to ensure occupant safety. In addition, fire-rated glass and glazing solutions are capable of providing additional benefits to occupants, including daylighting and thermal performance.

Fire-Protective vs. Fire-Resistive Glazing

Product performance, design, weight, cost, and delivery will vary depending on whether a glazing product is fire protective or fire resistive. This begs the question: What’s the difference?

In terms of performance, “fire-protective products limit the spread of fire and smoke. Fire-resistive products also limit the spread of fire and smoke but also act as a barrier to radiant heat,” says Jerry Cucchi of Aluflam.

“The barrier to radiant heat is an important distinction between the two and can have a significant impact on cost and schedule,” Cucchi says. “There are also differences in how the glass options are made and supplied. Fire protectives are thinner, lighter, and are more of a commodity product that can often be sourced from a different supplier than the hollow metal frames. Fire resistives are thicker, heavier, and are supplied as a system—frame and glass—from a single manufacturer.”

The fire-rated glazing market can be a challenging one to navigate. Suppliers continue to push the envelope of what solutions are possible, and codes are consistently being updated, along with adoption and enforcement.

Suppliers recommend that architects seek assistance from fire-rated glazing partners early and often. “In order to address misconceptions, we stress the importance of involving the manufacturer as early in the design process as possible to avoid issues—design and budget—later on,” Cucchi says.

Building owners or architects also frequently have questions about the fire rating of a particular application. The rating of a partition or barrier is not determined by the manufacturer but instead by the authority in the building’s jurisdiction. Manufacturers can help provide solutions when given the required specs; however, they are not the ones who can determine if you are meeting code. When selecting a fire-rated product, consider not only the appropriate product for a specific application but also make sure it will comply with local codes. After you determine which product is most functional, from that category you can determine which will be the most aesthetically pleasing in the application.

Several fire-rated glazing suppliers also offer continuing education opportunities to address market trends and common questions and concerns.

Fire-Rated Glazing Products Do more than Protect

These days, fire-rated glazing products do more than protect. Thanks to market demand, the glass industry has developed solutions that satisfy multiple needs, from daylighting to thermal performance to aesthetics. There are many popular trends that have emerged over the years, thanks to the technological developments that have made glass a more viable product for exterior and interior walls.

Following are just a few of the top fire-rated glazing trends for 2019.

Large Expanses

In the past, glass was not ideal for large expanses of buildings because it did not provide insulating properties that could prevent unwanted thermal heat gain or loss. Older buildings often have smaller windows and solid doors instead of full facades made of glass. Thanks to the advancements in glass technology and glazing, glass is now much more energy efficient. That, coupled with architects and buyers enjoying the benefits of daylighting and visibility, means many are specifying larger windows and glass installations in new construction and renovations. In response to demand, suppliers have developed solutions that maximize vision areas of glazing systems, including fire-rated systems. Larger lites and butt-glazed systems, both two sided and four sided, are more and more common in these applications.

Thermal Performance

As is the case with other exterior glazing systems, thermal performance remains a primary consideration. This not only keeps occupants comfortable in a temperature-controlled environment but can also provide energy efficiency, thus reducing heating and cooling costs. While some glazing can help absorb or reflect heat from the outside, additional benefits are present when fire-rated glazing is applied. Glazing systems, in conjunction with proper sealants, can play a key role in the building envelope by reducing unwanted air, heat, and moisture intrusion.

Matching Systems

As previously discussed, budget constraints often prevent architects and owners from specifying an entire building with fire-rated glazing systems and protective glazing that can help prevent intruders. Many architects and owners want areas that contain fire-rated glazing systems to match with their nonrated systems, according to David Vermeulen, national sales manager, Technical Glass Products. “Fire-rated frames tend be thicker to hold the fire-rated glass and provide the necessary level of fire defense,” he says. “In addition, many have limited mullion and cover caps options. While these framing systems are effective from a fire and life safety standpoint, they can cause aesthetic discrepancies at the visual transitions between rated and nonrated assemblies. We’ve seen an increase in projects calling for fire-rated glazing products that more closely resemble the look of ordinary window glass.”

Multifunctionality

Fire-rated glass oftentimes needs to support structural loads while also blocking flames, smoke, and heat from fires. But what about also providing additional security against intruders or burglaries? Glass that is multifunctional can provide a high level of fire and life safety while also offering resistance against bullets, blasts, intruders, or forced entry. Glass products that can meet these safety and security needs while also providing an aesthetically pleasing facade are trending. And that trend does not appear to be slowing down any time soon.

Weight Reduction

Added security often means adding extra layers or additional materials to glass to make it more durable. Fire-rated glass and security glass is often thicker than standard glass, which can make it really heavy, thus making doors harder to open. To accommodate for this, architects and builders must specify upgraded hinges and hardware. Some door manufacturers are looking for lighter-weight options to help accommodate for this challenge. One solution is fire-rated glass ceramics, which have a lower density than regular soda lime glass. Fire-rated glass ceramic products are trending in doors and other applications where the wall or window needs to move.

Fire Resistant over Fire Protective

As discussed earlier, there are two distinct performance categories—fire resistant and fire protective—that dictate fire-rated building requirements. Fire-protective products block the flames, while fire-resistant products also block the gases produced by fires as well as the radiant heat they create. These days, the industry is seeing more and more requests for fire-resistant glazing, partly because the demand for larger spans of interior glass has increased. In the example of corridors that feature lots of glass, architects must provide safe egress in the event of a fire. This is not only dictated by clear paths to exit the building but also by reducing the ability for fire and flames to spread. Fire-resistant glazing can help.

Increasing Inspections

Annual Fire and Egress Door Assembly Inspections are on the rise. Many local jurisdictions require that fire-rated doors be inspected annually to ensure they are fully functional over their lifespan. “This not only makes it critical that any replacement fire-rated glass is fully certified but also drives fire-rated door manufacturers to lightweight [glass ceramic products] right in their factory to ensure that the whole door is in compliance,” says Rob Botman, general manager, Glassopolis.