What is the vertical drop height that triggers a guardrail requirement?

• A. 30 inches
• B. 36 inches
• C. 24 inches
• D. 42 inches

Answer: (A)

Guardrails are installed to prevent falls from open edges of elevated surfaces like decks, balconies, and stair areas. The requirement kicks in when the vertical drop from the edge to the surface below reaches a height where a fall could cause injury. In this standard, that trigger is thirty inches. If the edge is at or above this height, a guardrail must be present and meet the required height and strength. Lower drops do not automatically require a guardrail under this item, and higher thresholds you might see in other codes apply to different contexts but are not the trigger here.