Energy performance, structural glazing and the future of architectural glass were big discussion topics during GlassCon Global, which concluded yesterday in Philadelphia. But the program also covered another critical topic: safety and security glazing. A number of presenters focused on the subject, covering matters such as blast mitigation design, protective glazing and school safety.
Eve Hinman with Hinman Consulting Engineers Inc., led a discussion on blast mitigating design of glazing.
“It’s not about designing a building, it’s about a community event,” said Hinman. “If they want to be a good neighbor, maybe they should protect the glass in their neighborhood.”
Looking at the example of the Oklahoma City bombing, she said a number of the survivors had injuries from glass. She said that window breakage causes enormous destruction and can completely destroy a building post-event.
“Downtime and injury effects make it a huge event,” she said.
According to Hinman, The exterior envelope is the first line of defense that the building has to offer in defending against an explosive attack. Although heavier, stiffer elements do resist more load, they also tend to cause brittle failure which can be highly hazardous. The design objectives are to reduce the flying debris and the air-blast pressure that enters the building and to reduce inquiries.
She said laminated glass is the chief tool for blast protection and the use of insulating panes includes lamination on the inside face.
Hinman said bigger windows are the weaker ones, as small lites break at higher pressures than the larger ones. She added that for existing systems, it’s preferred to use security film, attaching it to the mullion.
“It’s important to also consider that a rescuer may need to enter the building through the window with the laminated glass,” she said. “So you have many things to consider when selecting the materials for the window.”
Joe Smith, corporate director/senior vice president security engineering and applied sciences sector, Applied Research Associates Inc. USA, gave a presentation titled “Active Shooter: What to Expect, What to Do, is there a Role for Protective Glazing?” He explained that “active shooter” is something that is happening more frequently, given the increasing number of school shootings.
Smith said according to the Department of Homeland Security, an active shooter is “An individual actively engaged in killing or attempting to kill people in a confined and populated area; in most cases, active shooters use firearms and there is no pattern or method to their selection of victims.”
According to Smith, in 60 percent of cases studied by the FBI, the most powerful weapon used was a handgun. He said the range of preparation goes from very little to something that was prepared for many months, adding that most incidents happen in businesses and there is a median of five shots per event, not including the shooter.
The average time per event is 12 minutes, with a three-minute response time by police. About half the events are over by the time the police arrive and 67 percent are self-terminated by the attacker; 33 percent are stopped by the victims.
Smith said that for prevention or deterrence, create an environment of trust: “If you see something, say something.” Aside from uniformed guards, companies can add measures to improve security, including visitor sign-in, badging, sensors on doors and in remote areas, and all alarms/alerts. He also suggested delay or denying access. For example, Smith said that in the case of the Sandy Hook shooting, it was reported that the shooter failed to gain entry through locked doors and instead shot out adjacent windows.
Smith said it’s also important to consider how long it takes someone to get through the window, as this could be nefarious entry or it could be a rescuer.
To read more about GlassCon Global, look to the August 2014 issue of USGlass magazine.