Definition
Safety glass made by bonding two or more glass panes around an interlayer of polyvinyl butyral (PVB) film, so that when broken, the fragments stay adhered to the film rather than scattering.
Laminated glass is made by permanently bonding two sheets of glass around a polyvinyl butyral (PVB) interlayer under heat and pressure. The PVB film is the key: when laminated glass breaks, the fragments adhere to the interlayer rather than scattering as dangerous shards. The glass may crack extensively, but the pane holds together — making it a critical safety and security product.
Laminated vs. Tempered Glass
| Property |
Laminated |
Tempered |
| Break pattern |
Cracks but stays in frame |
Shatters into small cubes |
| Security |
Excellent (intruder must hit repeatedly) |
Poor (single blow shatters) |
| Sound reduction |
Good (PVB dampens vibration) |
Minimal added benefit |
| UV blocking |
99%+ (PVB blocks UV) |
No UV benefit |
| Hurricane/impact |
Yes (with impact-rated PVB) |
No (not impact rated) |
| Cost |
Higher |
Moderate |
Where Laminated Glass is Used
- Skylights and overhead glazing — required by code; prevents injury from falling glass if broken
- Hurricane/impact windows — heavy-duty PVB interlayer resists penetration by wind-borne debris
- Security glazing — multiple laminations create forced-entry resistance
- Acoustic windows — PVB interlayer significantly reduces sound transmission (STC improvement of 3–5 points)
- UV-sensitive applications — museums, art galleries, and homes with valuable furnishings benefit from the 99%+ UV blocking
Laminated Glass in IGUs
Laminated glass can be combined with the double-pane IGU format — typically as the interior pane — to combine thermal insulation with safety, security, and sound attenuation in a single unit.
