Each jurisdiction has to be looked at carefully as the requirements can vary considerably from city to city, or state to state. Since I work out of Northeastern Illinois I am mainly familiar with the Illinois accessibility code.
Approaching straight on from the front, a door that swings out towards you requires a clearance of 18″ minimum from the latch side of the door edge to the left or to the right. This is required when a door has both a latch and a closure. This is mostly scrutinized when the door is located in a narrow hallway or alcove. Therefore if you have a narrow hallway with a 36″ wide door and a 2″ frame at the end of the hallway, the minimum width of the hallway would be 56″. This assumes you would hold the hinge side of the frame tight to one of the hall walls. If space allows, a 58″ hall width would work better. This allows the door to stand at 90° in the open position.
Side approaches to the door have different requirements from the front approach discussed above.
