IRC 2018 Glass Railing Requirements
While this is not yet in effect, the 2018 International Residential Code (IRC) will include a code requirement for glass railing that is similar to the wording in the IBC.
Structural glass baluster panels. Guards with structural glass baluster panels shall be installed with an attached top rail or handrail. The top rail or handrail shall be supported by a minimum of three glass baluster panels, or shall be otherwise supported to remain in place should one glass baluster panel fail.
Exception: An attached top rail or handrail is not required where the glass baluster panels are laminated glass with two or more glass plies of equal thickness and of the same glass type.
In an application where the railing span is small, you do not need to use 3 panels if the top rail or handrail is large enough to withstand the load on its own. This would require selecting a top rail that can withstand 200 lb concentrated load or 50 lbs/ft uniform load and while attaching the ends in such a way that the top rail/handrail can withstand the load. Note: in a residential application, the handrail and top rail can be one and the same as the guard height minimum is 36″ while the handrail has to be located between 34″ and 38″ — this is not the same in the IBC as the guard minimum height is 42″.
Be sure you understand that there are different types of laminated glass. Watch this video to see how different interlayers will react under load.