What Is Blast-Resistant Glass and How Is It Tested?
In an explosion, the shock wave often breaks windows before it does any other damage to a building, and flying glass fragments cause a large share of injuries. Blast-resistant glass is designed to reduce that hazard.
How it is built
Blast-resistant glazing is usually laminated: two or more glass plies bonded with a tough plastic interlayer. When the glass cracks, the interlayer holds the fragments together. The glass must also be anchored in a frame and fixings that can carry the blast load, because a pane that leaves its frame in one piece can be just as dangerous.
How it is tested
Test standards expose glazing to a defined blast load and then classify the result. Common methods include shock-tube tests (for example EN 13541), open-air arena tests (for example ISO 16933) and the ASTM F1642 test method for glazing subject to airblast loadings. The result is a protection class that states the pressure and impulse the glazing resisted and how much hazardous debris entered the room.
What to specify
A good specification names the threat (charge size and stand-off distance), the test standard and the required class, and covers the whole assembly: glass, interlayer, frame, anchors and the wall around it.
Key takeaway
Ask for a test report that matches your threat level. A pane is only as strong as the frame it sits in.