Wired Glass Still A Misunderstood Product

By Author: FA Glass
Total Articles: 2
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Contrary to popular belief, wired glass has not been banned from use. Traditional wired glass can still be used in annealed glass applications—if it meets the wind and thermal load requirements—and in fire window assemblies that are not in hazardous locations. However, it is limited to 25 percent of the wall area. This size limitation applies to all fire protective glazing products.

Safety wired glass—although it looks like traditional wired—incorporates a safety film and meets both fire and Consumer Product Safety Commission impact safety requirements. It is suitable for use in any door, side lite or other hazardous location where safety is a concern of the International Building Code.

When specifying safety wired glass products, it is important to recognize that simply putting safety film on wired glass without prior testing and independent certification is not only inadequate, but a highly dangerous practice that violates code requirements. Not all films work; some can actually contribute to the spread of fire. The same concerns apply when putting safety film on existing wired glass in the field. It ...
... must be done under the guidelines of a certified field filming program to ensure that the new fire-rated safety wired glass meets the fire and impact safety requirements of the code.

The code history
Traditional wired glass (non-safety) is not banned. It can still be used in fire windows in non-hazardous locations, but is limited to 25 percent of the wall area. This size limitation applies to all fire protective glazing. Confusion in the marketplace continues to surround wired glass due in part to its code history. This meant that glazing used in hazardous locations such as doors and sidelites had to meet a minimum Category I impact test that stipulated 150 foot-pounds of impact and limited glazing area to 9 square feet. As the only fire-rated glazing product available at the time, traditional wired glass was granted a temporary exemption from meeting the CPSC standard. This exemption allowed wired glass manufacturers to meet the lowest impact level of the ANSI Z97.1 standard stipulating 100 foot-pounds of impact.

Clear, non-wired fire and safety glazing alternatives
Clear, non-wired fire and safety-rated glazing options are alternative products that meet all of the fire and safety requirements of the code when fully certified, for applications where the institutional look of wire is undesirable. These options include specialty tempered glass, heat reflective specialty tempered glass, specialty fire protective glass for 100-square-inch doorlites, filmed safety ceramics and laminated safety ceramics. Note, ceramic products must be filmed or laminated in order to be used in any hazardous locations, including doors and sidelites.

Clear fire-resistive products can be used in any fire-protective application and are required in any applications over 45 minutes, with the exception of 60-, 90- and 180-minute doors that might allow fire-protective glass up to 100 square inches. Examples of fire-resistive applications are one-hour and two-hour walls. Fire-resistive glass used in these walls does not have any area limitations because of its ability to fully block radiant heat, an important characteristic that wired glass and other fire-protective products lack.

When in doubt, safety glaze
It is safe to assume that confusion as to where you can and cannot use traditional wired glass will continue to linger. We are fortunate to live in a time when a variety of fire- and safety-rated glazing products are readily available. As the old saying goes, “An ounce of prevention is worth a pound of cure.” When in doubt, use safety glazing products to avoid potential injuries and liabilities.