This door may be made of one or more horizontal panels that open upward instead of outward.

• A. Swinging
• B. Sliding
• C. Folding
• D. Vertical

Answer: (D)

Doors that use horizontal panels and open upward move in a vertical plane, traveling up into the header rather than swinging on hinges or sliding sideways. This type is commonly called a vertical (overhead) door. The key idea is the motion path: upward movement along tracks means the door is not a swinging door, not a sliding door, and not a folding door. Swinging doors hinge and swing open, sliding doors move along a horizontal track, and folding doors hinge in sections that fold. Understanding this helps you identify how the door will behave during entry or forcible access and what hardware (tracks, springs, operators) you might encounter.