Elevators and Elevator Safety History
IntroductionIn order to address the safety aspects of elevators found in the past, it is necessary to cover the history of elevators. The concept of vertical movement of people and materials extends back many centuries. In addition, a discussion of elevator safety recognizes the fact that accidents and incidents associated with elevator use typically involve one or a few people at a time and is often not very news worthy. In addition, such events are normally confined to a building and seldom involve spectacular scenes and associated stories and images typical of other kinds of events, such as fires, explosions, crashes, structural failures, and weather events. Early elevators moved people and goods one floor. Advances allowed for movement to a few more floors, but fear of failures made the higher floors less desirable. With increased reliability and design improvements, elevators made skyscrapers feasible and high levels preferable.
Elevator TypesElevators move people and materials vertically. Over the years the kinds of elevators have expanded from simple freight elevators and passenger elevators to many other special types. Here is one list of elevator types that have emerged and exist today. Each type involves slightly different hazards and potentially adverse events.
Elevator Types Based on Function
- Passenger Elevators
The most common purpose for an elevator is to move people vertically among floors of a building.
- Freight Elevators
Another common kind of elevator moves materials vertically.
- Express Elevators
These elevators serve select floors in a high-rise building, bypassing the other floors. The approach shortens travel times.
- Residential Elevators
These elevators operate between levels within a single residence.
- Elevators for the Disabled
These elevators accommodate people in wheelchairs and with other disabilities. They are often found in smaller public buildings. Most passenger elevators can accommodate both able-bodied and disabled individuals.
- Sidewalk Elevators
These elevators move freight between a street level sidewalk in a city to a lower level in a building. They require barriers when at the street level to protect pedestrians from falling into the elevator opening and require a structure that opens a cover in the sidewalk to receive freight. When closed, the cover forms a section of the sidewalk that pedestrian can walk on.
- Stage Elevators
This kind of elevator occurs in theaters and lifts or lowers an entire stage filled with musicians and/or performers.
These are small elevators intended to move food, dishes, and cooking or serving equipment when a kitchen is at a different level than a patron dining area.
- Belted Manlift
This is a form of moving belt incorporating platforms to stand on and hand-holds where workers frequently move up and down between levels. Usually, there are shields at floor openings to prevent riders from getting caught at floor openings.
- Specialized Elevators
These are numerous kinds of elevators that move particular kinds of freight, such as cars in dense parking garages or manufacturing plants or boats as part of a waterway.
Parallel passenger cars with open doors that move continuously; cars on one side move up and those on the other side move down. Cars attach to a drive mechanism that moves a car at the top or bottom of travel to the reverse movement. There are no doors. Passengers must step on or off at appropriate times and locations. Mainly found in Europe.
- Urban Transport Elevators
These elevators move people in outdoor spaces rather than buildings. An example is moving visitors up and down a scenic hill.
Beside those listed, there are other specialized elevators.
Elevator Types Based on Mechanism
Elevators also have names based on the mechanism powering their movement.
- Traction Elevator
These elevators use electric motors, gears, and cables running over sheaves to raise and lower the elevator car. These elevators typically move faster than other types.
- Hydraulic Elevator
This kind of elevator uses pumps and hydraulic fluids to raise and lower the elevator cars. They travel a limited length (up to 6 to 8 floors), but can handle greater weights than traction elevators. The sidewalk elevator shown above is one type of hydraulic elevator.
- Climbing Elevator
This category of elevator contains its own power device, such as an electric or combustion engine. They are used commonly in construction and other temporary work situations.
The earliest use of an elevator is not known. It is clear that some form of lifting mechanism helped Egyptian construction and moved water. However, records show elevator use in the third century B.C. The oldest elevators were called lifts or hoists. The Roman architect Vitruvius made reference to the elevator invention of Archimedes, a Greek inventor, from about 236 B.C. It used hoisting ropes wound around a drum. Humans operated the ropes connected to a capstan.
Elevators were in use in ancient Rome. The most notable application was at the Roman Colosseum where slaves provided power for as many as 30 lifts that moved caged animals and gladiators from the lower level to the main floor. (See article on page 23.)
Lifts or hoists evolved slowly to carry passengers or freight. Hemp ropes were the main lifting mechanism and people or animals (sometimes water) provided the power for the ropes throughout the Middle Ages. Some used a screw type mechanism with people or animals turning the “drum” that wound or unwound the lifting rope.
The industrial revolution created a demand for more efficient lifting systems. Elevators were needed in coal mines for miners and for cars that moved the coal to the surface. Industry needed elevators to move supplies and products to and from production areas. An early recreational use elevator was “the ascending room” in London that gave customers a beautiful view of the city.
European royalty added elevators to their residences. Examples are those at Versailles in 1743 and the Russian Winter Palace in 1793.
With the introduction and wide use of steam power, elevators also relied on steam power to run them. Designs incorporated counterweights to make starting and stopping smoother.
New design features increased the capability of elevators. For example, in 1852 wire rope replaced hemp rope to greatly reduce failure of the lifting rope. Elisha Otis invented an elevator brake mechanism in 1852 that prevented a cab from falling if the cable broke. He demonstrated his design in 1854 at the Crystal Palace that was part of the New York World’s Fair.
In 1880 Werner von Siemens created the first electric powered elevator in Germany. Electric power increased elevator speed. Frank Sprague introduced floor control and acceleration control. In 1887 Alexander Miles invented the first automatic door that closed off the elevator shaft. Inventions continued to improved elevators and increase their safety.
Many inventions expanded the use of elevators. The early elevators typically involved only one change in floor level. With new design features, elevators could move between several floors and made multi-story buildings possible. Eventually, faster and more reliable designs made construction of high rise buildings feasible. Some elevators today travel as fast as 30 miles per hour.
Otis created an elevator manufacturing company that provided the first commercial passenger elevator in 1857 in New York City. In 1885 the first skyscraper, 10 stories, was built in Chicago, made possible by the Otis safety elevator.
The earliest elevators were moving platforms. One danger was falling from the lifting platform because one or more sides were open. That remains a danger for certain kinds of elevators with open sides, such as a paternosters (refer to video cited with definition). Falling is a danger for belted manlifts, since riders must be standing on the rider’s platform and grasping the handbar.
Another danger is a fall of the elevator car down a shaft when the lifting rope or cable breaks. The danger was reduced with a change from hemp rope to steel cables. In addition, the incorporation of multiple loops reduced the likelihood of failure.
The greatest reduction in incidents of falling cabs occurred with the invention of the elevator brake by Elisha Otis. The brake engages when an elevator car moves too rapidly. The brake engages along the guiding track inside the shaft.
With the increase in building heights and the longer elevator shafts, the potential for serious injuries and death increased. The need for a fail-safe brake system for the cars is critical.
Another danger is an elevator car gaining too much speed. Use of governors of various designs reduces the likelihood of this occurring.
Another danger occurs if someone falls into an elevator shaft. That has been significantly reduced with the installation of a door at each floor. The doors have interlocks to assure closure and prevent opening when the cab is not at the floor to be opened.
Another danger results when elevator occupants or contents get caught between the cab and the shaft or floor opening. That has been largely eliminated by a door on the cab that must be closed before the cab can move up or down. In most elevator designs, both the outer door and the inner door must be closed before an elevator can begin up or down travel. However, the danger exists for belted manlifts as riders move through floor openings.
When an elevator stops at a floor for exit or entry, there is a danger of tripping or falling if the car floor does not align with the floor at the stop (leveling). There may be a slight, but unexpected, step up or down.
Some elevators can start or stop too quickly. That can result in occupants falling. One means for reducing that is with the use of counterweights. Today, electronic controls manage the rate of acceleration from a stop or deceleration in approaching a stop.
At times an elevator stops working and terminates its movement between floors. That usually requires rescue assistance. It may involve opening the inner and outer doors at a location where occupants need a ladder or other assistance to exit to a floor. An open outer door may leave a space below the car is open to the shaft. That must be barricaded to prevent anyone from falling into the shaft. In some cases rescue may involve exiting through a hatch in the ceiling to the top of the car and then to a floor. A rare condition has occurred in which the rescuers must break the wall of the shaft to create an opening in line with the elevator doors.
Elevator construction and maintenance workers must barricade floor oopenings to prevent falling into the shaft.
Elevator repair workers face a danger of being crushed by a cab that moves into the lowest location (pit) and there is no clearance for the worker under the cab. This is a potential danger in the design of hydraulic elevators as well as cable-operated elevators.
Workers also face the danger of getting caught in the power and lifting equipment for an elevator. Depending on type of elevator and the travel distance, the location for the power and lifting equipment will vary. Often the equipment is located near the base of the shaft. In other designs, the mechanism may be on top of the cab or at the top of the shaft.
There are dangers for elevator maintenance workers from the electrical systems. There are low voltage systems for managing the logic of door closures and cab movement. There are high voltage dangers associated with the motors that power elevator movement. These dangers include arc flashes that result from starting and stopping equipment.
Control systems can fail leaving a car in a space between floors. Early controls were ropes pulled up or down to initiate, stop or reverse the up or down movement. Later passenger elevators required operators. Today push buttons establish the movement after interior and exterior doors are closed and locked by an interlock. Most today use computers to manage car motion requests and logic for most efficient movement of a car.
Elevator IncidentsThere are about 900,000 elevators in the United States. Together they complete billions of trips daily. Today, the number of accidents and injuries from elevators is relatively small. Overall, elevators are a safe mode of vertical movement. There are few sources of data that show the frequency and severity of elevator accidents. The methods for capturing data vary by jurisdiction. Many jurisdictions do not compile records routinely. One Internet report provides a summary of early information10.
1916 ReportAnother report from 191611 describes elevator fatalities in Chicago and its surrounding area during the period from December 1904 to March 1916. This report showed 40 elevator deaths per year in a single major metropolitan area during a 10-year study period. Peter M. Hoffman, Coroner of Chicago and Cook County, compiled this report. It provides summary information and abbreviated accounts of individual cases. All cases are fatalities. The coroner had no information on non-fatality injuries, but estimated that there were five non-fatal injury (mostly serious) cases for every fatality based on Chicago Police Department records.
Types of Elevator Accidents
|Accident Type||Number of Cases|
|Other than operator running the car||60|
|Working in elevator or in shaft||54|
|Getting on or off moving elevator||50|
|Loading or unloading elevator||47|
|Walking through open door into shaft||39|
|Looking into shaft and struck by car or doors||22|
|Trying to operate elevator from outside||16|
|Fell down or crowded too near gates in elevator||15|
|Slipping or falling of load in elevator||9|
|Operator lost control||6|
|Children playing in elevator without operator||5|
|Lever struck accidentally causing startup||5|
|Breaking of cable||5|
Types of Elevators Involved
|Elevator Type||Number of Cases|
Identified Elevator Accident Causes
|Cause||Number of Cases|
|Fell down elevator shaft||169|
|Crushed between elevator and floor, wall, doors, etc.||152|
|Killed by falling elevator||24|
|Struck by elevator||23|
|Crushed by counterweights||12|
|Crushed in elevator||8|
|Struck by falling objects other than elevator||7|
|Crushed by machinery of elevator||4|
The U.S. Department of Commerce published elevator accident statistics in a 1921 report12 . Data came from newspaper clippings extending from January 1913 to July 1918. The report grouped elevator accidents into three groups: public buildings (hotel, apartment, retail stores, offices), semipublic buildings (hospitals and garages), and industrial buildings.
Total Fatalities and Non-fatalities (annual average for 5.5 years)
The study also reported on the distribution of these data among shaft and shaft-door accidents. In addition, the study analyzed data from state industrial commissions or departments of labor for New York, Pennsylvania, Wisconsin, and Massachusetts, and data from three municipalities.
The report concluded that about 36 percent of the fatal accidents involve falling down a shaft and a smaller portion of non-fatal accidents also involved falling down a shaft. The second most frequent cause of accidents involved crushing hazards between car and sill or door frame. As a result, the report provided recommendations for codes and standards involving door latches and interlocks and other safety features.
2006 ReportThe Center to Protect Workers’ Rights (CPWR) conducted a more recent study13. The study relied on data from two sources. The source for workers was 1992 to 2003 records from the Census of Fatal Occupational Injures compiled by the U.S. Bureau of Labor Statistics from reports of work-related deaths. The other source for passengers came from the National Injury Information Clearinghouse of the Consumer Product Safety Commission for the period from 1997 to 2006. There were also data from NIOSH studies and data from two states. The study found 173 deaths for work on or near elevators, about 14 per year. The most frequent cause was falling into elevator shafts (49%). Most of these occurred during construction or maintenance. The report analyzed worker fatalities further to gain additional insights into accident causes and types. For elevator passengers, there were 68 fatalities during the study period, about 7 deaths per year. Most deaths involved falling into an elevator shaft, the majority where an elevator door opened and there was no car there. Most of the others involved getting caught in/between or struck by elevator parts.
Elevator Codes and Standards
Codes and standards for elevators slowly emerged during the early part of the 20th century. Before codes existed, there were other publications that offered design, construction, and maintenance recommendations14.
Similar to other early safety codes and standards, elevator codes became the responsibility of state governments. One of the earliest elevator codes was that of Wisconsin15. The first one occurred in 1912 and fell under the Industrial Commission. By 1918 the state began reviewing plans for new elevator installations and alterations to existing ones. At the same time the state instituted elevator inspections. Much later, in 1983, Wisconsin adopted ASME A17.1 (1981), the National Safety Code for Elevators and Escalators.
To illustrate the contents of early elevator codes a review of the 1920 Elevator Code of the Industrial Commission ofWisconsin16. shows detailed standards for the following:
- Plans, Inspections and Certificates
- Shaftway Enclosures
- Landing Doors and Gates
- Pits and Penthouses
- Cables and Counterweights
- Loads and Stresses
- Guide Rails
- Machines and Safety Devices
- General Safety
- Electrical Safety
During the early 1900s, the American Society of Mechanical Engineers (ASME) got involved in safety standards for a variety of equipment. ASME collaborated with other organizations, including the Department of Labor (formed in 1913) to establish a code for elevators.
Following World War 1, there was a building boom. ASME issued its first safety standards for elevator designs and operations in 1921. At that time ASME published a 25 page publication, A17, Safety Code for Elevators. Today the current version is jointly published by ASME and the Canadian Standards Association as ASME A17.7/CSA B44.7. Many state and local jurisdictions have adopted this standard.
Over time the elevator codes have become more complex with the introduction of new designs, materials, technologies, and control systems. The current codes address the complexities of today’s elevators, the need for regular inspections and maintenance and wide application of current codes.
Footnotes & References
- 10 Elevator Accidents 1870-1920, Elevator World, Inc. (https://www.elevatorworld.com/elevator-accidents-187 0-1920/) and
Lee Gray, Elevator Accidents 1870-1920: Causes, Elevator World, Inc. (https://www.elevatorworld.com/elevator-accidents-187 0-1920-causes/)
- 11 Elevator Dangers: 401 Fatal Accidents of Freight and Passenger Elevators in Chicago and Cook County, From December 1904 to March 1916 Inclusive, Public Safety Commission of Chicago and Cook County, 1916. (The Archives sends a special thanks to the University of Oregon Knight Library staff for providing a copy of this very rare document.)
- 12 C. E. Oakes and J. A. Dickinson, Results of A Survey of Elevator Interlocks and an Analysis of Elevator Accident Statistics, Department of Commerce, Technological Papers of the Bureau of Standards, No. 202, October 17, 1921.
- 13 Michael McCann and Norman Zaleski, Deaths and Injuries Involving Elevators and Escalators, The Center to Protect Workers’ Rights, July 2006.
- 14 M. A. O’Brien, Jr., A Treatise on the Elevator Industry, (A discussion of recommendations passed by the Legislature of Massachusetts.), Boston, 1915.
H. Robert Cullmer, Elevator Shaft Construction – Practical Suggestions for the Installation of Electric Elevators in Buildings, The William T. Comstock Company, New York 1912.
Maintenance of Elevator Hoisting Machines and Brakes, Executive Committee for the American Standard Safety Code for Elevators, Dumbwaiters, and Escalators, Washington, D.C., 1943.
- 15 State of Wisconsin, Important Dates in Wisconsin Elevator Code History, Rev 9-12-2017.
- 16 Elevator Code, Industrial Commission of Wisconsin, April 1920.