ADAS 2010 407.2.2.1 Elevator Visible and Audible Signals
Visible signal fixtures shall be centered at 72 inches minimum above the finish floor or ground. The visible signal elements shall be 2 1/2 inches minimum measured along the vertical center-line of the element. Signals shall be visible from the floor area adjacent to the hall call button.
Code according to 2010 ADAS. Check your state’s accessibility laws. Some states such as California, Georgia and Florida have additional requirements and standards.