A floor opening threshold is 12 inches.

A floor opening threshold is 12 inches.

• A. 8 inches
• B. 10 inches
• C. 14 inches
• D. 12 inches

Answer: (D)

Guarding floor openings is about preventing falls through gaps in floors. When a floor opening measures 12 inches or more in any direction, it must be guarded or covered to stop someone from stepping into the hole. This 12-inch threshold marks the point at which the hazard is treated as requiring protection, balancing safety with practicality. Protective measures include installing a solid cover that can support the load and be flush with the floor, or erecting a standard guardrail at the opening. Openings smaller than 12 inches tend not to require guarding under this rule, though other hazards could still apply.

Guarding floor openings is about preventing falls through gaps in floors. When a floor opening measures 12 inches or more in any direction, it must be guarded or covered to stop someone from stepping into the hole. This 12-inch threshold marks the point at which the hazard is treated as requiring protection, balancing safety with practicality. Protective measures include installing a solid cover that can support the load and be flush with the floor, or erecting a standard guardrail at the opening. Openings smaller than 12 inches tend not to require guarding under this rule, though other hazards could still apply.