Glass is a brittle material which stress resistance is defined by the surface tensile strength. For the structural analysis of glass in building the surface strength is described by statistical values (percentile of glass breakage related to surface stress). For this purpose multiple test samples are usually tested in defined test methods that include a constant stress rate of 2 N/mm?. Characteristic strength values with associated confidence levels are taken from the adapted distribution functions (here, from the logarithmic normal distribution). In case of particularly short-term effects such as impact loads or explosion pressure waves a high strain rate is a dominating influencing factor which results in a significant higher surface strength. Based on multiple high speed tests strain rate factors kmod for impulsive loads can be determined.

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