In the early 1980s, a glass failure prediction model (GFPM) was introd
uced to resolve differences in U.S. industry procedures used to determ
ine the minimum thickness of glass required to resist a specified unif
orm lateral pressure. The differences in these industry procedures con
tinue to cause problems for designers who are forced to choose between
two different glass thickness selection methods that result in differ
ent specified thicknesses of glass for the same loading. Since its int
roduction, the GFPM has helped resolve industry conflicts as it has ga
ined increasing acceptance. In the late 1980s, the GFPM was used to de
velop glass thickness selection information that is incorporated in AS
TM E 1300-94. The purpose of this paper is to provide documentation fo
r the ASTM E 1300-94 glass thickness selection procedure and to propos
e improvements. The proposed improvements include modifications to the
optional procedure for calculating the probability of failure of a re
ctangular glass plate, and the presentation of a new set of dual-unit
glass thickness selection charts.