Traditionally Installed Glazing. Determining Thickness

This article outlines the calculation rules that apply to glazing used in building structures in order to determine its thickness.

These rules define, on the one hand, the loads that must be taken into account and, on the other hand, the criteria that must be met depending on the installation method.

Since, on the one hand, the mechanical performance of glazing depends on the nature of its basic components and the way these components are combined in the final glazing unit, and, on the other hand, the load resulting from the glazing’s own weight cannot be known at the time of calculation—since the purpose of the calculation is precisely to determine the thickness of each pane of glass comprising it— the principle of the calculations is therefore to determine the minimum necessary and sufficient thickness of a monolithic annealed glass pane capable of withstanding the loads applied to it, and then to verify that the composition chosen a priori meets the minimum thickness obtained by calculation and the deflection criterion applicable to the structure in which the glazing is installed.

This first article addresses glazing installed in frames with glazing beads that meet the requirements of standard NF DTU No. 39, or when it consists of a tempered glass assembly. A second article, “Bonded (VEC) and Clipped (VEA) Exterior Glazing,” will address glazing when it is installed by bonding to a substrate (VEC – bonded exterior glazing) or point-fixed to a structure (VEA – clipped exterior glazing).

First, the loads acting on the glazing will be specified according to the installation method, followed by the calculation formulas used to determine the glazing thickness.

Calculation examples are provided to illustrate the steps required to determine the correct glazing configuration.