Escalators

An escalator is a moving staircase – a conveyor transport device for carrying people between floors of a building. The device consists of a motor-driven chain of individual, 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 one might install 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 layout considerations

A number of factors affect escalator design, including physical requirements, location, traffic patterns, safety considerations, and aesthetic preferences. Foremost, physical factors like the vertical and horizontal distance to be spanned must be considered. These factors will determine the length and pitch of the escalator. The building infrastructure must be able to support the heavy components. The escalator should be located where it can be easily seen by the general public. In department stores, customers should be able to view the merchandise easily. Furthermore, up and down escalator traffic should be physically separated and should not lead into confined spaces. Traffic patterns must also be anticipated. In some buildings, the objective is simply to move people from one floor to another, but in others there may be a more specific requirement, such as funneling visitors towards a main exit or exhibit. The escalators must be designed to carry the required number of passengers. For example, a single-width escalator traveling at about 1.5 feet (0.5 m) per second can move about 2000 people per hour. The carrying capacity of an escalator system must match the expected peak traffic demand, presuming that passengers ride single file. This is crucial if there are sudden increases in the number of riders. For example, escalators at stations must be designed to cater for the peak traffic flow discharged from a train, without causing excessive bunching at the escalator entrance. In this regard, escalators help in controlling the flow of people. For example, an escalator to an exit effectively discourages most people from using it as an entrance[clarification needed], and may reduce security concerns. Similarly, escalators often are used as the exit from airport security checkpoints. Such an egress point would still generally be staffed to prevent its use as an entrance during times of light pedestrian traffic. It is preferred that staircases be located adjacent to the escalator if the escalator is the primary means of transport between floors.[citation needed] It may also be necessary to provide an elevator lift near the escalator for wheelchairs and disabled people. Finally, consideration should be given to the aesthetics of the escalator.