48. ELEVATORS
With 325 million passenger trips each day (119 billion trips each year) in the United States and billions more worldwide, you would think that elevators are a fairly safe way to travel. And you would be correct: only approximately 27 people each year are killed by elevators.
The two most common types of elevators are those that use a hydraulic system and those that use a cable system. Hydraulic elevators lift and lower passenger cars with fluid. The elevator car is attached to an arm that is moved by pumping fluid (e.g., oil) in and out of a reservoir. To raise the car, fluid is pumped by a motor into the arm, and the car goes up. To lower the car, a valve is opened and fluid moves back into the reservoir. Elevators that use a cable system have steel ropes attached to the elevator car and a counterweight. A motor connected to a pulley system moves the ropes to raise and lower the car. Both types of elevators require a control system to tell the elevator what to do.
Fortunately, visions of an out-of-control elevator car plunging to the ground are mostly a product of Hollywood imagination. Elevator safety regulations have been established by the American Society of Mechanical Engineers and International Building Codes. The likelihood of an elevator falling down a shaft is very low because of several safety mechanisms built into the design of elevators. First, multiple steel cables, usually six to eight, each with the ability to hold the car and counterweight by itself, are attached to an elevator car. If a single cable breaks, the other cables will prevent the car from falling. The counterweights also serve as a safety measure because they are a bit heavier than an empty car. Even without any other cables attached to an empty car, or a car with just a few people, the counterweights would move down and the elevator would be pulled up. Second, friction brakes under an elevator car engage gradually when a car moves too quickly. As an elevator car falls and builds up speed, the brakes work to slow the car. Third, in case of a power outage, electromagnetic brakes engage to hold the elevator in place. Fourth, automatic brakes engage if an elevator car gets too close to the top or bottom of an elevator shaft. The last line of safety is a shock absorber at the bottom of an elevator shaft. There is also no need to worry that an elevator has too many people on it: elevator doors will remain open and the car will not move if it is overloaded.
Although plunging to the bottom of the shaft is exceedingly unlikely, elevators can malfunction, and people can be injured by elevators due to electrical or mechanical failures. For example, problems with an elevator’s cables can cause the car to drop in the shaft before safety mechanisms take over. The sudden drop and stop can cause injuries. Defective wiring in an elevator raises the risk of electrocution. But the majority of elevator injuries occur when people slip, trip, or fall when they enter or exit an elevator. This can happen when the elevator floor is not level with the building floor. The elderly are especially at risk for elevator injuries, with approximately 2,640 injuries each year (one-third of all elevator injuries) occurring in people 65 years and older in the U.S. Children age 4 years and younger suffer approximately 824 injuries each year, with the majority (70.3%) of injuries caused when an elevator door closes on a body part. Elevator malfunctions may trap people inside. Usually, people are freed after a short time, although there are reports of people being confined inside an elevator for more than 24 hours.
People who work in or near elevator shafts account for 50% of all deaths associated with elevators. These workers include elevator installers and repair and maintenance technicians. The majority (56%) of these deaths occur when workers fall into open elevator shafts. From 1992 to 2009, 89 people died while using an elevator at work and from 1997 to 2010, 91 passengers died while using an elevator while they were not at work. Falls into elevator shafts, when an elevator door opens and there is no car, accounted for about half of all deaths.
Simple common sense practices should reduce the risk of elevator deaths and injuries. For example, before you enter an elevator, wait for passengers to leave the elevator. If there are too many people in the elevator, wait for the next car. Don’t try to stop a closing elevator door with your hands or feet. If you are already on the elevator and want to hold the door open for someone, use the door open button. As you enter or exit an elevator car, watch your step and look down to ensure the surfaces are level and that, indeed, the car is there. After you are on the elevator, make sure that your clothing, backpack, keys, and bags are clear of the closing door. In the event that an elevator stops while you are riding, stay in the car, remain calm, and use the elevator emergency telephone or alarm or your own phone to alert authorities. Do not try to pry the doors open or climb out of the elevator car. Use the stairs, not an elevator, if there is an earthquake or fire in the building.
In fact, you should take the stairs instead of an elevator whenever you can. Using the stairs is good exercise and better for your health.
SUMMARY
Preventability (85)
You can often take the stairs instead of the elevator—and for a bit of exercise, you probably should.
Likelihood (2)
The safety mechanisms built into elevators make an elevator falling out of control highly unlikely.
Severe injury or death is the likely outcome of the unlikely event that an elevator car falls from a significant height.
REFERENCES
Consumerwatch.com. (n.d.). Elevators. Retrieved from http://consumerwatch.com/workplace-public-safety/elevators/
Elevator Escalator Safety Foundation. (n.d.). Fun facts. Retrieved from https://www.eesf.org/fun-facts/
O’Neil, J., Steele, G. K., Huisingh, C., & Smith, G. A. (2007). Elevator-related injuries to children in the United States, 1990 through 2004. Clinical Pediatrics, 46, 619–625.
Paumgarten, N. (2008, April 21). Up and then down: The lives of elevators. New Yorker.
Steele, G. K., O’Neil, J., Huisingh, C., & Smith, G. A. (2010). Elevator-related injuries to older adults in the United States, 1990 to 2006. Journal of Trauma and Acute Care Surgery, 68, 188.