and prisons.

Bunk beds are normally supported by four poles or pillars, one at each corner of the bed. A ladder or a flight of stairs leads to the upper bed, which normally features a railing to prevent the sleeper from falling off. Some models also have a privacy curtain for the lower bunk. Because of the need for a ladder and the height of the upper bed, the U.S. Consumer Product Safety Commission recommends using the top bunk