According to the Building Code, the total area of plastic glazing in unprotected openings should not exceed what percentage of the wall face area?

The total area of plastic glazing in unprotected openings being limited to 25 percent of the wall face area is established to ensure safety and structural integrity in building design. This regulation primarily addresses fire resistance and the risk associated with using plastic materials, which can be less durable and more flammable than traditional glass.

By restricting the area to 25 percent, the code aims to minimize potential hazards related to fire propagation through unprotected openings. A larger area could significantly increase the risk of flames and heat transferring through the openings, which may compromise the building's safety. Thus, this limitation is a critical aspect of building codes that helps protect occupants and property by controlling the amount of combustible materials that can be used in the external facades of structures.