The construction
Several plies of glass bonded under heat and pressure with thick polymer interlayers — PVB or polyurethane. The number and thickness of plies and interlayers set the rating.
When a round strikes, the outer ply cracks and deforms the projectile, spreading its point load. Each subsequent layer absorbs more of the remaining energy, and the interlayers hold the whole assembly together so the panel keeps functioning as a barrier after the first impact. That last property matters: ballistic ratings specify multiple rounds, so a panel that shattered after one would fail the test.
Why it is the default
Optics. All-glass construction, so it reads as glass. Polycarbonate and acrylic are excellent materials but they do not look like glass, and in a showroom or an office frontage that is noticeable.
Durability of the surface. The exposed faces are glass. They can be cleaned with normal glass cleaner, they resist scratching, and they do not yellow under Mumbai’s UV. A polycarbonate face will scratch during routine cleaning and will discolour over years.
Documented performance. It is the most widely tested ballistic construction, so specifying to a rating is a matter of selecting a tested build rather than extrapolating.
The weight problem
For any given rating, laminated glass is significantly heavier than polycarbonate or glass-clad polycarbonate.
That has consequences beyond the glass:
- the frame section and its reinforcement have to carry it
- hinges, rollers and locks on any opening panel must be rated for the weight
- the supporting structure may need checking on a large installation
- handling and installation on site is a heavier operation
Where weight is the binding constraint — an upper floor, a lightweight partition, a large opening panel — polycarbonate-based builds exist precisely for that reason.
Spall
Laminated glass can spall: fragments thrown from the protected face on impact even without penetration.
Whether that matters depends on how close people stand. At a teller window or a reception counter, a no-spall layer on the inner face is standard. On a perimeter window with a desk well back from it, it is often unnecessary.
Useful side effects
A thick multi-ply laminate is an extremely effective acoustic barrier, so ballistic glazing is typically much quieter than the standard glazing it replaces. It also blocks essentially all UV, for the same reason ordinary laminated glass does.
Where thermal performance matters too, the ballistic laminate becomes one leaf of an insulated unit.
See the full bullet-resistant range for the comparison across constructions.