According to UL 681, an opening to be burglar inaccessible must be more than how many feet above the ground or the roof of the adjoining building?

• A. 12 feet
• B. 18 feet
• C. 24 feet
• D. 30 feet

Answer: (B)

The important idea here is how UL 681 defines when an opening is considered burglar inaccessible. The standard sets a height threshold: if an opening is more than 18 feet above the ground or above the roof of an adjoining building, it’s treated as burglar inaccessible. That means at heights over 18 feet, a burglar would have great difficulty reaching the opening with ordinary ladders or climbing from nearby structures, reducing the risk.

So 18 feet is the key threshold because it reflects a practical limit of typical access methods. If it were only 12 feet, a ladder could easily reach it; if it were 24 or 30 feet, those heights are far beyond standard access attempts and wouldn’t align with how the standard evaluates burglar-inaccessibility.