Wired glass is almost as common in schools as dry-erase boards. You see it in classroom doors, administration windows and corridor lights. Whenever codes have dictated the use of fire-rated glazing, wired glass has been the predominant choice. It has been a reliable, economical solution in the promotion of life safety.
So it undoubtedly came as a surprise to some when the International Building Code (IBC, section 2406) adopted new standards that eliminate the use of traditional wired glass in K-12 schools, daycare centers and athletic facilities. How could such a popular product fall out of favor so quickly and completely?
The answer lies not in how wired glass responds to fire, but how it responds to human impact. Contrary to public perception, wired glass is not “breakproof.” The wires often are misinterpreted as adding a level of security, when in fact they only are there to hold the glass in place during a fire. Actually, wired glass breaks quite easily, and the wires can cause significant injuries by forming dangerous snags when the glass is broken.
That's bad news for a school corridor full of active students, running and jostling each other on the way to class. Glass in that setting is likely to encounter a great deal of physical contact. On a day-to-day basis, there's a much greater risk of breakage from human impact than from fire. If wired glass is being used, the threat of serious injury increases.
For a long time, wired glass was the only fire-rated glazing material available. No other glass could endure the intense heat of a fire without vacating the opening. Because nothing was available that could meet both types of code requirements, the CPSC gave wired glass a special exemption from impact-safety standards. Fire safety was considered the more pressing need.
But times changed. Newer, “wireless” glass products, the result of advanced technology, could withstand both fire and impact. Although it looks like typical window glass when installed, these products have capabilities far beyond traditional glass.
In addition to new glass options arising, statistical evidence regarding wired glass-related injuries began to mount. As the new IBC was being formed, a special ad-hoc committee reviewed the data related to wired-glass injuries. They discovered that the majority of incidents occurred in schools or athletic facilities.
One parent of a student who suffered permanent nerve damage from broken wired glass spearheaded a grassroots campaign to have the exemption removed.
The committee recommended curtailing the CPSC exemption, and the International Code Council (ICC) accepted its recommendation. All glass in “hazardous locations” of schools and athletic facilities now will be required to offer high-impact safety. The exemption still applies to other commercial facilities, although there is an effort being lobbied to remove that exemption as well.