Connecticut State Legislative Office Building
Nature of Project
Blast mitigation, spandrel glass strengthening
Scope of Project
Square feet of of glass protected – 12,000
Spandrel panels reinforced - 155
1/4" polycarbonate sheet behind spandrels (mechanically attached)
Type of Film Installed
Armorcoat 14-mil clear fragment retention film
Type of Polycarbonate Installed
GE 1/4’’ Lexan
After a blast assessment was carried out by a well-respected blast consultant, it was determind that the state legislative office building required its glass, spandrel areas and window framing needed to be strengthened. After being awarded the job, Commercial Window Shield developed a two-part project process:
1. Install thick, 14-mil film, mechanically attached to steel framed, mainly operable windows.
2. Install thick polycarbonate panels behind spandrel glass and framing located above a drop ceiling.
Once Commercial Window Shield analyzed the project, it determined that the film-installation component of the project could not be done as designed by the architect and blast consultant. Rather, the company figured out that the windows had to be taken apart. The 14-mil film was then applied edge-to-edge on the interior surface of the glass. Structural silicone had to be applied in a two-step process to entirely encapsulate the glass in the frame. The second step involved reapplying the glazing stops and then applying a second application of structural silicone to ensure adequate contact and strength. The result was strong blast resistant fenestration system that was not only more effective than the original specification but less expensive.
The second component of the project called for the installation of thick polycarbonate panels behind spandrel glass and attaching it to the existing window framing. Normally, this would not be a difficult process, except that the spandrels were located above a drop ceiling and there was little access to the area. The installation of the polycarbonate was going to be extremely messy and disruptive to the building occupants – the state’s senators and legislators.
Once on site, Commercial Window Shield was able to come up with an alternate approach. Workers accessed the spandrel by going above the ceiling and using a heavy steel sub-frame they designed that could be installed by placing very small holes through the drywall instead of totally removing it. The sub-frame received the polycarbonate and was a stronger system than originally designed. There was no net change to the contract price for the work or design for this second component of the project.
The project was completed slightly ahead of schedule and to everyone’s satisfaction.