🔍 Key Concepts

• SOLAS and fire safety design for stair towers and vertical escape routes • Purpose of keeping doors closed in vertical trunk/stair towers during voyages • Conditions under which remote‑operated or automatic fire doors may remain open

💭 Think About

• Which option best matches the idea of maintaining the stair tower as an effective fire boundary while still allowing normal movement of crew? • Think about how quickly a fire and smoke can spread vertically if doors are left open—what design feature or procedure would safely control that risk? • Among the choices, which one describes a system of control for the door positions, not just a convenience for crew comfort?

✅ Before You Answer

• Verify what SOLAS and U.S. regulations say about fire doors in main vertical zones and stair towers • Check whether manual crew assignment alone is considered reliable enough for doors to be left open underway • Confirm whether remote or automatic closing arrangements are specifically mentioned as a condition for leaving doors in the open position