Can the Elevator Fall?
Short Answer – No.
Despite what you may see in the movies, it is essentially impossible for a modern passenger elevator to fall down the shaft. Modern cable type elevators use steel cables that have the cab connected to one end of the cable and a heaver counterweight assembly connected to the other. The cable elevator is called a “Traction” elevator because it is moved by traction of the cables wrapped over a motor drive pulley.
Traction elevators have a normally-engaged, spring-loaded brake (similar to automobile brakes) on the drive machine that keeps the cab stationary when the motor is not running. If any operational problem is detected, the brake clamps down to stop the elevator. That sensation of a sudden stop is what causes most people to feel like the elevator has “fallen”. Actually, since the counterweight weighs more than the cab, if the brakes did fail, the elevator would “fall” up instead of down. Newer elevators also have a separate emergency brake system. Other safety sensors that monitor the doors, hoistway, and cab will stop the elevator and set the brake if a malfunction is detected.
But what about the cables breaking?
An elevator cab is typically suspended by five to eight steel cables, each of which is capable on its own of supporting the fully loaded elevator. In the very unlikely case of a cable breaking, just one remaining cable would still support the elevator. The chance of all cables breaking at the same time is almost impossible. In fact, prior to the September 11th terrorist attacks, the only known free-fall incident in a modern steel-cable public elevator happened in 1945 when a B-25 bomber struck the Empire State Building in fog, severing the cables of an elevator cab, which fell from the 75th floor all the way to the bottom of the building, seriously injuring (though not killing) the elevator operator.
In addition to the cables, there is an independent safety system which detects whether the elevator is descending faster than its maximum designed speed. The safety system is comprised of a speed governor and brake shoes that clamp down along the vertical rails in the shaft, stopping the elevator quickly, but not so abruptly as to cause injury. Also, a hydraulic buffer is installed at the bottom of the shaft to slow and stop an elevator that travels below the bottom floor – even at full speed.
Statistically speaking, elevators are extremely safe. Their safety record is unsurpassed by any other transportation system. In the United States, an estimated 700,000 elevators transport about 325 million people every day safely to their destination.
But incidents do happen. According to data provided by the U.S. Bureau of Labor Statistics and the Consumer Product Safety Commission, there are about 20 elevator related deaths per year, (compared to around 40,000 automobile deaths). Most of these elevator related deaths involve construction or maintenance personnel working on or near the elevators. The deaths that involved the general public were normally due to someone trying to get out of a stalled elevator unassisted or otherwise entering the elevator shaft without the proper training.
So, forget what you see in the movies, stay in the elevator until helps arrives, it’s the safest place to be.