In 1956, a study on elevator efficiency at Mayo Clinic was completed, resulting in a change to improve service to patients.
The work came as a result of a series of studies of New Building elevator operation by the Building Committee, General Service, and the Westinghouse Co. Specifically, they are moving one car from the north bank of patient elevators to the formerly unused sixth shaft in the south bank. The south bank would become a six-car operation.
Why the change? Because checks and re-checks proved that six cars working in unison in a single bank provide better service plus more economical operation than “split bank” (i. e., running several cars in each bank) operation.
Efficiency of an elevator system is determined by the average length of time users must wait for service. The formula for this “interval of good service” equation is “round-trip-time divided by number of cars in use.”
Good service is an interval of 25 to 40 seconds of waiting. The study showed an average wait of more than 50 seconds for cars in the north bank and about 41 seconds for the south. Studies by Westinghouse engineers indicated that six cars in one bank would result in waiting intervals of only 23.5 seconds.