A ladder is a vertical or inclined device that allows workers to gain access to elevated surfaces. There are two common types of ladders: ropes ladders and rigid ladders.
Rope ladders are easy to store, retract, and carry but not stable. Rigid ladders are more stable but usually bulky and heavy. Rigid ladders can be made by wood, steel, aluminum, and fiber glass. Rigid ladders can be categorized by their structures and shapes including crossover, extension, fixed, and platform ladders. Commericalized ladders often specified by weight capacity and length (reach).