Two panes of glass for strength and one pane for added insulation.
A special silicone glazing process helps keep laminated insulating glass from breaking away from the frame. Laminated insulating glass is composed of three panes of glass: two panes of glass bonded together with a strong, clear interlayer for impact resistance and one pane for added insulation. Once sealed, the glass “sandwich” behaves as a single unit and is transparent like ordinary glass.