Why do commercial doors open out , We are building a baseball museum in an 1800's bank building. Does the main entree door have to open out,and does the exit sign have a specific height requirement over door.
Yes, public building must have the exits open outward for emergency fire exit. "Emergency exit door must swing in the direction of travel" In this case, outward.
Many people have lost their lives due to pile ups at exit doors that did not open out. The pressure from panicked people pushing against the closed door prevents its opening and people die.
The size, location etc. are all set by NFPA 101-2000 regulations. Check with your local code enforcement people and see it they have any specific amendments to this in place. This is typically "Title 24" stuff dealing with life safety and access. In any case; "No projections into the exit route or doorway may protrude so as to reduce the head height to less than 6 feet 8 inches. I think that answers your height question.
There are many regulations concerning this area. It depends on the building class and use, occupancy load etc. A bit much to get into here. Be guided by a professional or Architect on this.