Construction isn’t an exact science. Every contractor–from framers and dry-wallers to glazers and electricians–is used to making adjustments on the fly to compensate for the errors and irregularities that crop up during a project.
But not all materials can be trimmed to fit or jimmied into place. This is especially the case with bullet proof glass. Any project that includes a bullet resistant barrier system needs to allow for a second set of “hard measurements” to be taken once the structural elements are in place.
You Can’t Scribe Bullet Resistant Glass
When a tight fit and smooth finish are called for, the accepted practice is to scribe the finish pieces on site, so that they match the reality of what was built, not the ideal shown in the drawings. For example, it’s customary for millworkers to leave a little room at the ends of their pieces, so that the installers can trim them to on the spot and get a tight fit.
“But most of our materials can’t be scribed,” explains Total Security Solutions vice president Jim Richards. “That’s why, once that wall is built or flooring is in, we like to get our own hard dimensions, or get the dimensions taken again by the contractor or glazer. That way we can make sure that our materials will fit within very close tolerances.”
For example, Jim points out that when a soffit is built one half inch lower than planned, that’s nothing to almost any other tradesman: A switch plate is moved one-half inch, a few pieces of trim cut down, a light fixture pushed out a touch. But a custom-cut piece of bullet resistant glass-clad polycarbonate transparency is not going to fit in that space, and there’s nothing you can do on-site to make it fit. That bullet proof glass will need to get shipped back to the Total Security Solutions facility to be trimmed on a water-jet cutter. There is no quick fix.
Planning to Avoid Bullet Resistant Installation Delays
Discovering a last-minute discrepancy between the measurements and reality isn’t necessarily the end of the world: Some bullet resistant materials (like DuPont™ Kevlar® fiber wall reinforcement and some frames) can be trimmed on site. “There are some things you can modify in the field to address these situations,” Jim explains, “But to get an ideal overall fit and finish, we find that projects go a lot better if you can get that last set of hard dimensions during fabrication.”
Your project timeline should allow for three to four weeks between sending those final hard dimensions to the bullet proof company and taking delivery of the bullet proof system. This makes it possible to use these final, verified measurements as the basis for every piece of the finished system.
Planning for a final set of confirmed “hard dimensions” minimizes installation hiccups, and eliminates the possibility of a catastrophic delay.
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