The Benefits of Security Glazing

NEWTOWN, Conn. — Tragedies such as Sandy Hook Elementary in Newtown, Connecticut, have parents and administrators across the country clamoring for solutions to make schools more secure. Doors and windows – more specifically, the glass — are under significant scrutiny.

For extra security, laminated glass is an easy, cost-effective measure in protecting against forced entry and bullet resistance. Compared with traditional annealed or tempered glass, laminated glass can secure the building more effectively.

Laminated glass is made from a tough plastic interlayer bonded between two pieces of glass. Invisible to the naked eye, this interlayer gives laminated glass the same clear visual benefits as ordinary glass, an important security feature. From inside, occupants can see someone approaching the school. From outside, responders can locate the intruder or victims. Because it is impact resistant, laminated glass is a no nonsense approach for enhancing the protection of school windows and doors.

Renewed Need for Extra Security
Administrators and teachers agree that everyone should feel safe at school. Parents feel better dropping off their kids knowing a school has taken measures to assess and upgrade security.

More than just a facility, school is where families send their kids to learn, participate in sports and clubs, perform in musicals and plays, and much more. A school is why a family buys a home in a specific neighborhood, and it is what ties a community together. Schools frequently are used as emergency management centers or shelters in times of crisis, making security an important attribute to the building, even after teaching hours.

In recent years, schools are not the safe havens they once were. Since 1992, there have been 387 shootings in U.S. schools ( The most recent involving fatalities occurred December 14, 2012, at Sandy Hook Elementary. Twenty children and six adults died at the school. The gunman killed himself and had shot his mother earlier that morning. That’s 28 deaths tied to one event. No one can predict whether an attack will ever happen, but it is important that schools are prepared for anything.

Schools React to Potential Threats
Following the Sandy Hook Elementary shooting, parents, teachers, concerned citizens, school administrators, and legislators joined in discussions across the country about how this tragedy and future shootings could be prevented. There were conversations about gun control, awareness and care for the mentally unstable, as well as improving school safety through better communication systems, security measures, intruder drill training, and more. School districts everywhere are looking at how they can keep students, teachers, and faculty safe.

What the School Construction Industry Can Do
Windows and doors are the easiest point of entry into a school, but they don’t have to be. Installing laminated security glass for all windows and doors makes forced entry much more difficult. Laminated glass is fabricated with a tough, protective interlayer, typically of polyvinyl butyral (PVB), which is bonded with heat and pressure between two pieces of glass. Using thicker interlayers increases impact resistance. Upon impact, laminated glass will shatter but glass shards remain held together by the bonded interlayer. Risks associated with flying or falling glass are minimized.

Laminated security glass stands up to multiple assaults from a blunt or sharp object used to gain entry. If an intruder tries to break through a window or door side lite, it would take several blows before achieving access through security glass. This allows valuable time for anyone inside the school to call the police, lockdown interior doors or classrooms, or move students to a safer area.

From a glazing standpoint, school architects and administrators may consider the following when designing new or retrofit glazing systems:
• Glass should provide inherent health, safety, and security benefits that can help mitigate disasters.
• Natural daylight is essential for psychological benefits of students and teachers.
• Glass should provide visibility for critical passageways and entry areas.
• Sustained functionality – basic functions of the school can operate following a natural or manmade disaster.

When specifying laminated glass, threat levels should be considered:
• Entry doors have been the most vulnerable in many school shootings. Hurricane rated high-impact (large missile) glass, or even ballistic glass should be considered. As in the case of Sandy Hook, the shooter penetrated the side lite of the door and then reached through to open it. This “break and reach” ability of the intruder must be delayed or stopped. High performance glass provides resistance, while still providing much needed visibility.
• Existing doors may need to be replaced completely if bullet resistant glazing is specified, as the framing system for such heavy configurations is specialized.
• Access doors with a double entry lobby to the school should be equipped with laminated security glazing that overlays the Maghull Double Glazing windows allowing them to have the ability to restrain forced entry/burglary resistance capability in accordance with UL 972 or ASTM F 1233 — Class 1.
• At a minimum, first floor glass should be equipped with basic laminated glass (typically requires a 0.030 inch thick interlayer). This will deter ingress, retain glass, and slow “break and reach.” Forced ingress glazing, which uses a thicker interlayer, will offer greater protection. Laminated glass can be retrofitted into most existing window and door systems and can contribute to compliance for security windows per ASTM E2395 – Security Performance of Window and Door Assemblies with and without Glazing Impact.
• If budgets do not permit replacement of windows, security film can be post applied over existing windows and doors. This option offers some of the benefits of laminated glass but provides less resistance against an intruder, and, like other laminated glass options that are not bullet resistant, will not stop a bullet. Security film also modifies the post breakage behavior of glass, but may allow time to take additional action versus non-enhanced glazing.

When guns are the choice of weaponry, it requires several shots from a 9mm, .357 or .45 caliber handgun to make a hole large enough to put a fist through to unlock a door or window. In some cases, the intruder may be temporarily confused, as the glass isn’t “behaving” as expected. There are many documented “smash and grab” attempts at burglary, where would-be intruders give up because they are generating too much noise and attention.

Success Stories
Laminated glass has been around and in use in various forms for generations. Invented in 1903 by French chemist Edouard Benedictus, laminated glass has been used for decades in automobile windshields to greatly reduce injuries. It is commonly used in high-risk buildings such as embassies and federal buildings, as well as museums. Laminated glass protects great treasures such as the Mona Lisa, the U.S. Constitution, and London’s Crown Jewels.

After the devastation caused by Hurricane Andrew in 1992, laminated glass became the standard in Florida and other coastal regions. Building code requirements were established to lessen the amount of destruction caused from high winds and to ensure occupant safety.

In the aftermath of events like the Oklahoma City bombing (1995) and the September 11 (2001) terrorist attacks, enhancements to laminated glass configurations ensure that glazing in Federal and other public buildings are blast resistant. Dozens of lives were saved by blast resistant laminated glass when the Pentagon, newly remodeled, was attacked on September 11. The shock waves following an explosion can send glass shards flying for miles and generally cause about 70 percent of the injuries following an explosion.

Additional Benefits of Laminated Glass
Along with safety and security enhancing features, laminated glass offers schools other benefits. Laminated glass dampens sound coming in from the outside, making it an ideal choice for schools located in noisy neighborhoods or urban environments. Numerous studies have shown that children concentrate and can learn better in a quiet space.

Laminated glass reduces solar heat gain and UV rays going into a building, making it more comfortable and healthful for students. Finally, as coastal residents know, hurricane-rated laminated glass protects against natural disasters. Laminated glass is versatile, readily available, affordable, easy to install, and it can be used toward LEED certification in energy, recycling, indoor environment quality, and acoustics.

Keeping Kids Safe and Secure
According to survey data collected by the National Center for Educational Statistics in 1994-1996, the average age of public schools throughout the U.S. is 42. While there is a need for building better schools, there can be funding and time constraints. When new buildings cannot be erected, the architectural community must look at available options to modernize, update, and safeguard existing schools. Laminated glass remains one of the easiest, most cost-effective measures available for enhancing student and faculty safety.