Bullet-Resistant Glass (BRG) can be ideal in certain situations. It is transparent, allowing the window to remain in use, and since it is a permanent installation, it is always ready to protect. However, it can have some severe drawbacks:
1. Depending on the protection level needed, BRG can cost between $25 and $100 per square foot just for the material; however, it is not a drop-in replacement for a conventional window design. To convert unbuilt construction or develop a retrofit for it in older construction can easily make the cost reach $400 -$600 per square foot once you consider:
- Local approvals and permits
- Engineering approval
- Architectural review
- Current window removal
- Wall/window frame reinforcement
- Site installation
- Interior sheetrock and trim repair, exterior siding repair
2. It is heavy, weighing between 14 and 30 pounds per square foot. This can make it challenging to add as a retrofit as this weight may exceed the structural ratings of the building walls. It is also difficult to transport, handle, and install. This is especially true in multi-story buildings.
3. A converted BRG window can no longer be used as an egress.
4. It is impractical to install as a door, as it would make the door extremely heavy, making it cumbersome to open and close and it would prohibit the use of conventional hinges to support the weight (adding more cost). Glass in a door is really only practical when limited to small portal windows.
Using a BBP fabric shade can resolve some of these issues:
- It is less than half the cost of BRG (the exact price will vary based on the details of the installation).
- It weighs less than one pound per square foot.
- It requires no modifications to the existing window, which then can continue to open and close as normal and act as an egress.
- It is only deployed as needed.
- When used to protect a door, there are no modifications to the door itself, allowing the door to be standard residential or commercial construction for size and weight.