Concerns over Hydraulic Elevators
“Is there a good reason why hydraulic elevators do not need to meet the same codes as a traction elevator? In the US there are about three times as many hydraulic elevators as traction elevators. Yet very few of these elevators have safety devices to stop them in an uncontrolled fall or unintended movement. There is little information available about how many accidents there are from people tripping in or out of a mis-leveled elevator, but this is the most common occurrence.
Consumerwatch states The U.S. Bureau of Labor Statistics and the Consumer Product Safety Commission (CPSC) is not authorized to regulate elevators as it does other products such as automobiles or personal equipment. CPSC which reports on injury and death associated with elevators. Report injuries from elevators affect about 10,200 people per year, with the majority of these accidents being related to elevator door malfunction and elevator misalignment with floors.
Hydraulic elevators are slow moving. They are pushed up by hydraulic fluid that is contained in a closed system. If there is a small leak in the system the elevator will have the tendency to sink and move away from the floor level creating a trip hazard. In some cases when there is a large leak from failure of a packing or the jack assembly itself ruptures. A hydraulic elevator will fall at an uncontrolled speed causing severe damage to passengers and the equipment.
Many states and cities are moving to replace any hydraulic cylinders manufactured prior to 1972. These hydraulic cylinders were typically a single bottom design and are more prone to catastrophic failures. Jack assemblies after 1972 were of a double bottom design and less likely to have this type of catastrophic failure.”
Traction elevator designs do not have these problems as they are inherently required to have unintended car movement sensing in most cases. RAM prefers to offer the traction counterweight design we helped pioneer over 20 years ago for this and many other reasons.