The use of glass in lift shafts is set out in BS EN 81: Safety rules for the construction and installation of lifts. Little of the standard relates to glass but states that only laminated glass can be used. Laminated toughened glass can be used to enable two-edge support or bolt fixing.
Glazing to lift shafts is often in the form of a full height barrier and should resist all three loads detailed in BS 6399: Loading for buildings. The thickness of the glass will depend on the size, support method and design loads relevant to the building but shall at least withstand a point load of 300N without permanent deflection or full load deflection greater than 15mm.