Post-breakage behavior

Recent developments in polyvinyl butyral (PVB) interlayer technology offer the opportunity to use laminated glass as structural material. In properly designed applications, laminated glass—even when broken—can help support permanent loads.

The post-breakage behavior is a key reason why architects specify structural PVB interlayer to strengthen glass. If the glass breaks, the laminate tends to remain in place, containing shards and retaining enough functionality to provide support and protection until a replacement can be installed.

Structural laminated glass can be a viable option for applications in which traditional solid materials simply won’t fulfill an architect’s aesthetic vision or the design needs of a building or space—yet where post-breakage safety is paramount. A stiff interlayer such as Saflex® Structural helps to make “structural laminated glass” and greatly expands the possibilities for glass floors, stairs, balustrades, fins, and beams.

Strong glass made with Saflex helps maintain the integrity of the glazing system under load, protecting the building envelope while preventing injury and damage from glass fallout.

Thinner glass

Furthermore, because they provide added rigidity, structural PVB interlayers can provide needed support with a reduced glass thickness—resulting in cost savings for applications such as façades, roofs and partitions. Or, when specified with traditional glass thickness, structural interlayers may allow for laminated glass to be installed in larger widths or lengths.

Saflex Structural is designed for applications where added interlayer rigidity, post-breakage performance, and enhanced durability is required.


Compared with conventional clear PVB, Saflex Structural allows for:

  • Sustaining higher loads with the same glass thickness
  • Reducing glass thickness and/or avoiding strengthened glass while keeping the same structural capacity
  • Good sealant compatibility with most wet sealants (as tested in intimate contact with PVB edges)
  • Excellent edge stability and resistance to edge delamination

Like conventional PVB interlayers, Saflex Structural interlayer:

  • Has processing traits similar to conventional PVB interlayers, including autoclave, trim, and edge treatments
  • Presents no air or tin side sensitivity to glass, allowing for multilayer glass and interlayer constructions
  • Has very low haze levels, even on angles
  • Can retain glass shards after breakage in hot, cold, and wet applications
  • Is compatible with the Vanceva® color interlayer system and other Saflex interlayers

Structural Glass Calculator


The calculator was developed to allow users to compare a variety of different interlayer technologies to determine the best laminated configuration for specific glazing applications.

Start calculating now

Glass railings and exposed edges

Saflex® DG41 PVB provides new possibilities

Architectural glass railings can dramatically enhance a building’s facade, and for occupants, the unobstructed views are priceless. Exposed edges have long been a challenge for manufacturers and installers, but advancements in interlayer products have resolved many of these issues. Saflex DG41 polyvinyl butyral (PVB) interlayers are ideal for laminated glass railings, especially those in hot, humid climates. Laminated glass comprising these interlayers can withstand high humidity and temperature deviations between hot and cold climates without compromising the integrity of the laminate edge when properly laminated.

Saflex Structural glass railings Bulletin

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