Industry experts answered questions about security glazing amid a panel discussion hosted by the Fenestration and Glazing Industry Alliance (FGIA) during a webinar titled, “Security Glazing for Storefront and Fenestration.”
The first question asked was about the changes on the horizon for security glazing standards.
Julia Schimmelpenningh, architectural industry technical manager of the advanced material interlayers business at Eastman Chemical Co., said that recent events have shown how well security glazing products work which is bringing an increase in awareness. She explained that standards pertaining to these projects will always be reviewed to see what the needs and trends are and, if necessary, modifications will take place.
Ivan Zuniga, product manager for storefronts, entrances and framing at Kawneer, answered a question regarding whether there are any International Code Council (ICC) requirements for security levels of glazing products.
“It’s important to remember that the I-codes are managed by the ICC, which addresses life and safety. They don’t address security as part of the codes,” he said, adding that government entities such as the Department of Defense and the General Services Administration have specific security requirements. “Codes are not addressing security glazing. This is added to specifications by the designer or architect.”
Another webinar attendee asked how glass and glazing requirements for small and large missile impact differ and whether wet glazing is required. Vaughn Schauss, manager of technical consultancy for the Americas at Kuraray, said that for small missile systems, glass is designed with an .060 interlayer whereas large missile systems are designed with a .090 interlayer.
“As far as dry versus wet glazing, this is determined by how much the laminated glass deflects during pressure cycling. In small missile testing both lites don’t break so you can use dry glazing even with PVB, but in large missile testing both lites will break. If using PVB it will need to be wet glazed so the glass stays in the frame during cycling,” he said. “Designing with a stiffer interlayer will allow you to go with a dry glazed system.”
Zuniga addressed considerations one should keep in mind to improve the survivability of a security glazing system during a vandalism or forced entry event. He said that glazing storefront systems from the inside have become the industry standard to maintain the integrity of the security glazing.
“Having the glass attached to the frame through structural silicone glazing or tape may be necessary. That’s, at minimum, something that needs to be considered … Pay attention to the anchors and keep in mind that the calculations included are often to resist windload forces but not the forces of a security event,” he said.
Schauss explained that if retrofitting a project to include increased security, those using a self-adhesive film will need to ensure it’s anchored to the framing system for it to do its job. Another option is to replace the glass.
“You can take out the existing glass and put in laminated glass. In this case, you may be limited due to the frame depth as to how much glass and what level of security you can achieve,” he said. “The best option is to take out the entire glazing system and replace it with a designed system with the level of security you want.”
When using security glazing applications, Schimmelpenningh pointed out that they often come with the added benefit of noise abatement due to the dampening effects that come with an interlayer.
“Heavier glass has better low-frequency absorption for noise abatement whereas a softer interlayer has better performance with upper frequencies … Security glazing systems give better acoustic performance than a standard insulating glass unit,” she said.
Finally, Zuniga addressed how to include both energy efficiency requirements as well as impact requirements in a glazing system.
“Most of the time you’re not going to be able to sandwich laminated glass and a low-E coating and get the same level of thermal performance in security glazing. You often will have to have an external sacrificial lite with the solar or thermal properties and then the security glazing on the inside,” he said, adding that first the specifier must verify that the selected security glazing is appropriate for an exterior application due to UV and infrared radiation.
Click here to read part one of this article, which gave an overview of safety and security glazing standards.