Part 4 of the standard applies to vertical glazing and horizontal glazing inclined in the direction of potential impacts that is designed to prevent persons falling from circulation areas. It applies to the following categories of glazing. Category A: Glazing conforming to Part 2 or 3 of this standard that has to withstand horizontal imposed loads as it does not have a loadbearing parapet rail or a crossrail installed in front of the glazing at the height required to withstand horizontal imposed loads in accordance with DIN EN 1991-1-1:2010-12 and DIN EN 1991-1-1/NA:2010-12, 6.4. Category B: Glass parapets restrained at their base and comprising individual glass panels connected by a continuous handrail at the required height. Handrails can be fastened to the upper edge of the glass or by clamping discs in accordance with Part 3 of this standard. Category C: Glazing in accordance with Part 2 or 3 of this standard that does not have to withstand horizontal imposed loads at the required height and belongs to one of the following groups: C1: Balustrade infill panels C2: Glazing below a loadbearing crossbar installed at the required height C3: Glazing with a loadbearing crossrail installed in front of the glass at the required height