What role do guards play in building safety?

Guards play a critical role in building safety primarily by preventing falls from elevated areas such as hallways or the edges of stairways. These protective barriers are essential for ensuring that individuals do not accidentally step or fall off these elevated surfaces, which could lead to serious injuries. The establishment of guardrails at strategic points around stairs and balconies forms a necessary safety measure that helps safeguard the wellbeing of occupants and visitors within the building.

While the other choices may involve certain aspects of building design and safety, they do not specifically address the primary function of guards. For instance, supporting structural integrity around doorways relates more to the framework and load-bearing aspects of construction rather than guardrails. Similarly, marking boundaries of stair railings pertains more to visual delineation than to active safety prevention, and enhancing aesthetic appeal involves design choices that do not directly relate to safety. Therefore, preventing falls is the most accurate description of the crucial role that guards serve in building safety.