Escalator in shopping mall

An escalator is a type of vertical transportation in the form of a moving staircase – a conveyor transport device for carrying people between floors of a building. The device consists of a motor-driven chain of individually linked steps that move up or down on tracks, allowing the step treads to remain horizontal.Escalators are used around the world to move pedestrian traffic in places where elevators would be impractical.Principal areas of usage include department stores, shopping malls, airports, transit systems,convention centers, hotels, arenas, stadiums, and public buildings.

Escalators have the capacity to move large numbers of people, and they can be placed in the same physical space as a staircase. They have no waiting interval (except during very heavy traffic), they can be used to guide people toward main exits or special exhibits, and they may be weatherproofed for outdoor use. A non-functioning escalator can function as a normal staircase, whereas many other conveyances become useless when they break down.

Design and safety

Escalators, like moving walkways, are often powered by constant-speed alternating current motors and move at approximately 0.3–0.6 meters (1–2 ft) per second. The typical angle of inclination of an escalator to the horizontal floor level is 30 degrees with a standard rise up to about 18 meters (60 ft). Modern escalators have single-piece aluminum or stainless steel steps that move on a system of tracks in a continuous loop.

Escalators have three typical configuration options: parallel (up and down escalators side by side or separated by a distance, seen often in metro stations and multilevel motion picture theaters), crisscross(minimizes space requirements by "stacking" escalators that go in one direction, frequently used in department stores or shopping centers), and multiple parallel (two or more escalators together that travel in one direction next to one or two escalators in the same bank that travel in the other direction).

As a safety measure, escalators are required to have moving handrails that keep pace with the movement of the steps. This helps riders steady themselves, especially when stepping onto the moving stairs. Occasionally, a handrail will move at a slightly different speed from the steps, causing it to "creep" slowly forward or backward relative to the steps. The loss of synchronization between handrail and step speed can result from slippage and wear.

The direction of escalator movement (up or down) can be permanently set, or be controlled by personnel according to the predominant flow of the crowd, or be controlled automatically. In some setups, direction is controlled automatically by whoever arrives first, whether at the bottom or at the top (the system is programmed so that the direction is not reversed while a passenger is on the escalator).

Safety

Safety is a major concern in escalator design. In India, where women wear saris, there are heavy chances of getting the pally entangled in the escalator. As a result, a special sari guard is built into most escalators.

There is a risk of foot injuries for children wearing footwear such as crocs and 

flip-flops that might get caught in escalator mechanism.This was due to the softness of the shoe's material combined with the smaller size of children's feet.

Fire protection of an escalator may be provided by adding automatic fire detection and suppression systems inside the dust collection and engineer pit, in addition to any water sprinkler system installed in the ceiling. To limit the danger caused by overheating, ventilation for the spaces that contain the motors and gears must be provided, and small targeted clean agent automatic extinguishing systems can be installed in these areas. Fire protection of an escalator floor opening may be provided by adding automatic sprinklers or fireproof shutters to the opening, or by escalator installation in an enclosed fire-protected hall.