The International Building Code dictates that a building with four or more stories either above or below grade requires a larger elevator. The code requires that the elevator access all floors and accomodate a 24″ x 84″ stretcher in the open position. This requirement is larger than the minimum elevator dimensions which are dictated by accessibility requirements.
The elevator needs to be identified with the star of life international medical services symbol a minimum of 3″ high and placed on both sides of the door frame.
While it isn’t explicitly called out, the hallway and entrances to units should also be planned out with the stretcher in mind.