service stair

例句：

1. 1.The service stairs are located at the top of the building.
   服务楼梯位于大楼顶部。
2. 2.The elevator is the most convenient way to reach the upper floors.
   电梯是到达上层楼层最方便的方式。
3. 3. The service stairs are not suitable for people with mobility issues.
   服务楼梯不适合行动不便的人。