The use of laminated safety glass (LSG) is indispensable in modern façade and structural glass construction. The application covers various areas, such as decorative glass, soundproof glass, special static requirements, burglar resistance, fall protection, overhead glazing or particularly demanding glass structures such as bullet and explosion protection.


To produce laminated safety glass, polymer interlayers are laminated with two or more panes of glass to form a laminated safety glass package. The industry offers a wide range of specialized LSG interlayers (e. g. PVB, ionomer, EVA, PU) and corresponding LSG laminate structures for these applications.

The VSG working group includes members from universities and colleges and the supplier industry, as well as VSG interlayer manufacturers. The aim is to work on current topics and issues with as holistic a solution approach as possible. The results should be implementable in user practice. These can be incorporated into current construction projects, but also set new standards in the medium term. In particular, active involvement in standardization (e. g. in DIN, EN and ISO working groups) should be mentioned here.

The current project of the VSG working group is the “Quantification of the residual load-bearing capacity of laminated safety glass”. Residual load-bearing capacity refers to the resistance of a destroyed system to complete failure in order to ensure sufficient time to replace the broken glazing for a certain period of time.

At present, this property is tested using complex and cost-intensive component tests. Computational or other non-destructive verification methods have not been established for the condition of the residual load-bearing capacity. The aim is to gain further detailed knowledge about the material behaviour and to develop alternative verification methods. The classification of different interlayer types into requirement categories or groups to be developed is being considered. These could then be incorporated into standardization work.


The FKG promotes and supports research projects and theses in this field and carries out its own projects, the results of which are available to member companies:
Franz, J.: Investigations into the residual load-bearing capacity of broken glazing, Springer 2015

Botz, M.: Contribution to the experimental and numerical description of laminated glass with PVB interlayer in the intact and broken state, Uni BW M (2020)

Schuster, M.; Schneider, J. & Nguyen, T.A.: Investigations on the execution and evaluation of the Pummel test for polyvinyl butyral based interlayers. Glass Struct Eng (2020).

Institute of Structural Analysis and Design, Technical University of Darmstadt; Institute of Building Design and Building Physics; University of the Federal Armed Forces Munich: Quantification of the residual load-bearing capacity of laminated glass: REST-VSG: Computational and experimental studies to determine the residual load-bearing capacity of laminated glass; University of the Federal Armed Forces Munich, Fraunhofer IRB Verlag T3378; 2020

Wellershoff, F.; Illguth, M.; van der Horst, T.: Load-bearing behaviour of broken laminated safety glass made of toughened safety glass in the biaxial stress state, Glasbau 2021

Wellershoff, F.; Illguth, M.: Laminated glass – Bulge tests; Membrane stiffness of broken laminated safety glass/ESG under quasi-static loading, FKG internal report, 2018

Wellershoff, F.; Illguth, M. Beyer, J: Laminated glass – Biaxial tests; Residual load-bearing capacity of laminated safety glass/LSG under variable strain rates and principal stresses, FKG internal report, 2022