[Main entrance]

Thanks Tom, very useful info on background.  I'm not quite sure what you were saying in your second paragraph, can you clarify?

[Main entrance]

Why then does one not normally see panic bars on main entrance doors?

[Main entrance]

As all doors in the external envelope of a building can be used as a final exit when do you not have to put a crash bar/push pad type mechanism on a main entrance door or other frequently used door to a school building?  E.g. some doors have a digital lock on them which has a lever handle internally.