Why Elevators Essentially Never Free-Fall: Engineering Safety

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Safety Myths
Otis's Break
Modern Design
Brake Systems
Rare Accidents

Safety Myths

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    Elevators are extremely safe, with no deaths from snapped cables in modern models.

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    American elevators make 18 billion trips yearly, far safer than cars or escalators.

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    Ancient Greek elevators were primitive but modern safety began with Elisha Otis.

Basic principles of Newtonian mechanics, specifically gravitational acceleration, free fall, and the relationship between force, mass, and acceleration.
The physics of friction and mechanical braking, including how kinetic energy is converted into thermal energy to arrest motion.
The fundamentals of simple machines, particularly how pulleys, cables, and counterweight systems distribute loads in mechanical lifts.
Basic concepts of electrical circuits and fail-safe engineering design, where a loss of power defaults the system to a safe, locked state.
The specific mechanics of centrifugal governors and safety gears (safeties) that mechanically clamp onto guide rails during overspeed events.
Fail-safe and redundant systems design philosophy as applied to other high-risk transport engineering domains, such as aviation and high-speed rail.
National and international safety standards and regulatory codes governing vertical transit, such as ASME A17.1 and EN 81.
The role of modern IoT sensors, real-time diagnostic software, and programmable electronic safety systems (PESSRAL) in predictive elevator maintenance.
720.6K views18.6Klikes9:37@cheddarOriginal Release: 2020-04-23

Modern elevators are extremely safe due to multiple redundant safety systems, including a factor of safety of 11 (meaning cables can hold 11 times the fully loaded car's weight), electrically released brakes that clamp down during power outages, counterweights, and shock absorbers, which together prevent the free-fall scenarios commonly depicted in movies.