Hello,
I agree with pieman with regards to companies cutting service time down. Basically, the service mechanics have too many elevators to service and the elevator companies will not hire to compensate for an over-crowded service route. I started my elevator company 3 years ago, and I tell my customers my mechanics will spend at least 45 to 60 minutes per elevator no matter the type of elevator or floors. (we do not service high rises) 15 to 20 minutes just is not enough time to properly service an elevator and unfortunately routine maintenance is not getting done.
To answer your question, there are no such minimum time requirements for service. I do feel that 45 to 60 minutes is adequate, but you will have to take into consideration the travel or landings of the elevator.
