Staircase

Staircases provide vertical access to connected floors in a multi-story building, and are a functional part of it.

An exterior stairway is a stair in a separate structure attached to the rest of the building body,[3] and can either be enclosed or exposed to the elements.

Such temporary exposed stairways are sometimes used in conjunction with scaffolding on construction sites, or permanently as an emergency exit.

In many cases, indoor stairs are placed far inside the building structure, and it is often not easy to get access to a wall on the outside where it would be natural to have a regular window for letting daylight in.

For fire safety it can be advantageous that both the walls, ceiling and the stairs themselves in a stairwell are made of non-combustible materials, and be illuminated with daylight during the day and artificial lighting at darkness.