Mechanical strength of float glasses manufactured by different enterprises with the same technological regimes and by one glass plant under different technological conditions was investigated relatively to the top (atmosphere) and bottom (tin) surfaces by means of the ring-on-ring bending method. The lack of statistical methods for estimating the technical strength of float glass was considered. It was shown that to obtain useful information about the mechanical properties of industrial sheet glass it is necessary to use a statistical interval of distribution of no more than 25 MPa with testing not less than 25-30 specimens. This will provide the means to analyze the information regarding the statistical levels of sheet glass strength. The levels of strength with average stresses at failure 56, 81, 138, 188 and 262 MPa were defined.
