Wired glass to lose its safety designation

by sadia_badhon | April 2, 2020 12:37 pm

By Stephanie Miller

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Since 1990, wired glass has been the sole material cited in the National Building Code (NBC) for safety glazing in fire-rated applications. This is going to change soon. The change will have major implications for designers and contractors working with fire-rated glazing materials.

There is evidence that even before NBC adopts updated requirements for safety glazing in its forthcoming editions, designers and contractors may need to make some changes today to avoid future liability.

Fire-rated glass has, for many years, been an effective barrier in preventing the passage of hot gas, flame, and smoke. Hence, NBC 3.1.9.1, Fire Stopping of Service Penetrations, was updated in 1990 to note openings “in a fire separation having a fire-resistance rating of not more than 1 hour may  be protected with fixed wired glass assemblies.”

However, unless it is organically coated, wired glass falls far short as a safety glazing because it does not safely withstand human impact. The wire embedded in the glass is meant to hold the material together after it breaks in a fire, reducing the spread of flames, smoke, and hot gasses. The wire accomplishes this, but when the assembly breaks from human contact, the resulting jagged glass shards and strong wire can cause lacerations to anyone moving forcefully through the broken material. Evidence has stacked up over the years that these products cause as much, if not more, damage than they stop.

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This damage is troubling as the material has been used in schools across Canada, among other applications. Even though the Canadian Hospitals Injuries Reporting and Prevention Program does not track the number of injuries attributable to falls through wired glass in detail, Laura Rosella of the Dalla Lana School of Public Health at the University of Toronto, published research in 2015 based on U.S. injury estimates that suggest approximately 368 wired glass injuries take place each year in Canadian schools.

The problem has been widely recognized, and manufacturers and regulatory authorities have taken action. Since the 1990s, glass manufacturers have committed to developing safer safety glazing solutions that can meet the demands of fire-rated applications. In 2003, the U.S. building codes began banning the use of wired glass in hazardous locations, such as doors. In 2015, Canada began working on this.

Rewriting wired glass standards

In 2015, the Canadian Glass Association (CGA) issued an advisory recommending wired glass not be used in any location subject to human impact due to the threat of injury. Around that time, the Canadian General Standards Board (CGSB) had convened a glass committee to rewrite the country’s safety glazing standards. Thomas Zaremba, a partner with Roetzel & Andress, an expert in building codes and standards, and a member of the CGSB committee, notes the resulting standard is very much modelled on the United States’ American National Standards Institute (ANSI) Z97.1, Safety Glazing Materials Used in Buildings – Safety Performance Specifications and Methods of Test. In fact, it includes input from the then chair and members of ANSI Z97.1 committee. The intended result was comparable standards that will make it easier to source fire-rated products throughout North America.

“If a product passes the safety glazing requirements of 16 [Codes of Federal Regulations] CFR 1201, Safety Standard for Architectural Glazing Materials, or ANSI Z97.1, it will pass the new Canadian safety glazing standard as well,” Zaremba says.

In 2016, CGSB withdrew CAN/CGSB12.11-M90, Wired Safety Glass. The standard had tested wired glass’ impact resistance with three tests at 300, 450, and a maximum of 1200-mm (12, 18, and 47-in.).
drop height for an impactor providing 136 N⋅m (100 ft-lb) of impact energy. It is a test that standard 6-mm (¼-in.) polished wired glass was able to pass successfully. The following February, CGSB replaced CAN/CGSB 12.11-M90 with CAN/CGSB 12.1–2017, Safety Glazing. The updated standard now covers all forms of safety glazing, including tempered and laminated glass as well as glass products with a safety film.

With this change, as CGA points out, wired glass not organically coated and tested to the new safety glazing standard, will no longer be considered a safety glass in Canada. In fact, CGA recommends “wired glass should no longer be used in doors or other locations subject to human impact.”

The challenge, however, is standards are voluntary—and thus, unenforceable—until adopted by a code. Yet, even voluntary standards may push some degree of responsibility on architects and contractors.

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Codifying the standard

The next step to broadening the impact of the revised standard is for NBC to incorporate the standard into its model code. This has been a lengthy process, in part because the now defunct wired glass standard is referenced throughout NBC, and each of those references must be updated.

The process of updating the 2015 edition of NBC is nearing completion. Revisions to the 2015 edition of NBC were available for public review through December 23, 2019. Once the review period ended, comments were analyzed by the committees updating the Canadian Commission on Building and Fire Codes (CCBFC). Proposed changes will either be approved, withdrawn, or adapted and resubmitted for further comment. Once approved, these changes will be published in the soon-to-be-released 2020 edition of NBC.

If approved, however, the current allowance under NBC 3.1.9.1 for fixed wired glass assemblies within a fire separation will read, “[G]lazing in all fixed and operable panels of doors shall conform to Class A of CAN/CGSB-12.1-2017, Safety Glazing.”

Impact of code changes

It is true codes likely will not eliminate exceptions for wired glass until NBC 2020 (expected to be published this year), and potentially much later, as provinces and other local jurisdictions would then have to formally adopt the new edition for the revised language to become enforceable. The adoption may take several years, as each province has the option of not updating its codes. However, design and construction professionals may still have some responsibility to make a change today.

As Zaremba explains, “The CGSB glass committee has adopted a new safety glazing standard. Whether it is in the new model building code or not, that standard will likely be used in potential litigation if there is an accident involving wired glass in violation of the new standard.”

Each designer and contractor will have an individual choice to make, but given the evidence of injury, specifying or installing a product not meeting the new expectations established by the CGSB standard could result in a liability.

“If I were specifying product in Canada right now, I would identify whether the location is hazardous and, if it is, I would not specify monolithic wired glass, whether or not my jurisdiction permits it. I would insist the use of safety glazing,” Zaremba says.

Contractors managing maintenance or renovations may also have some responsibility in making glazing updates. The National Fire Protection Association (NFPA) technical committee has recently held a discussion around building owners’ responsibility under NFPA 80, Standard for Fire Doors and Other Opening Protectives, to update monolithic wired glass in hazardous locations.

“The committee went back and forth over a variety of iterations and finally settled on one that basically said if it was installed at a time when monolithic wired glass was permitted in a hazardous location it can remain there. If, however, it is damaged and must be replaced, monolithic wired glass cannot be used to replace it in a hazardous location. You would have to upgrade the product to one that passes current safety glazing standards,” Zaremba explains. This recommendation will be made in the 2022 edition of NFPA 80.

The bottom line

It is important to remember, even with the revised standards, wired glass can be used in hazardous locations—just not in its monolithic configuration. Wired glass products that are coated or otherwise manufactured and tested to comply with the new safety glazing standard can be used even in hazardous fire-rated applications. It should never be used in any non-fire-rated application.

“The only location where wired glass should ever have been allowed is a location in an application that required a fire-rated glazing,” Zaremba emphasizes. “That is the essential positive value of monolithic wired glass: that it can withstand a fire test and stop the passage of hot gas, flame, and smoke.”

It is also important to note that there are many products on the market today providing safe fire protection without the risk of danger brought by wired glass. Fire safety films, applied and tested for performance by the glass fabricator, are one effective alternative. Numerous glass ceramic products have been manufactured to resist high temperature and thermal shock for up to 180 minutes. These fire-protective products effectively stop flame, smoke, and hot gasses in vulnerable areas, and can be installed as a cost-effective alternative to wired glass in fire windows and fire door vision lites.

With the number of fire-rated safety glazing options available today, designers and contractors have little reason to risk liability or future injuries.

As Zaremba puts it, “We now know there are multiple types of organic film coatings that can be applied to these products and that will pass the fire test, so there is really no excuse for using monolithic wired glass in a hazardous location anymore, whether it is fire-rated or not.”

[4]Stephanie Miller leads marketing and communications for Vetrotech Saint-Gobain in North America. Miller can be reached via e-mail at stephanie.miller@saint-gobain.com.

Source URL: https://www.constructioncanada.net/wired-glass-to-lose-its-safety-designation/

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