Escalator
A powered, continuously moving staircase that carries people between floors.
Quick Answer
An escalator is a powered, continuously moving staircase that carries people between floors in high-traffic buildings such as airports, malls, and transit stations. A motor-driven chain pulls steps along a truss, and handrails move in sync. Escalator safety and installation are governed by ASME A17.1 and local building codes.
The Full Picture
An escalator consists of a steel truss spanning between floors, a set of linked steps pulled by chains around drive sprockets, moving handrails, and a drive machine and controls located in the upper or lower machine space. The steps flatten at each landing so passengers can step on and off safely.
Escalators are chosen where large numbers of people move between a small number of levels, because they have higher throughput than elevators and no waiting. Typical inclination is about 30 degrees, and step width and speed determine capacity. Moving walkways use the same principle on a level or gently inclined path.
Escalators are not generally counted as part of the required means of egress in the building code, so a building still needs compliant stairs. Openings through floors for escalators also create fire and smoke concerns, and designs often address these with enclosures or shutters, protective sprinkler arrangements, or other code-permitted methods.
On projects, escalators are a specialty subcontract that depends on accurate floor openings, structural supports, and power at the machine spaces. The truss is often delivered in sections or complete, so crane access and sequencing must be planned before the finishes around the opening are installed.
Real Examples
Common Misconceptions
People assume: Escalators count as an exit stair in an emergency.
Actually: The building code generally does not allow escalators to serve as required means of egress, so separate compliant exit stairs are still needed.
People assume: An escalator can be treated as simple equipment installed at the end of a job.
Actually: Its floor opening, structural support, truss delivery path, power, and fire protection details need to be coordinated early with the structural and finish trades.
Frequently Asked Questions
How is an escalator different from an elevator?
An escalator moves continuously and carries many people without waiting, while an elevator carries groups in a car on demand. Escalators suit high-traffic spans of a few floors, and elevators suit all heights and accessibility needs.
Do escalators satisfy accessibility requirements?
No. Accessible routes between levels are generally provided by elevators or ramps, so an escalator does not replace them.
What code covers escalators?
ASME A17.1 is the primary safety standard, used together with the adopted building code and local amendments.
What is a moving walkway?
A moving walkway, or travelator, is a powered conveyor for pedestrians on a level or slightly inclined path, commonly used in airports.