We are adding a mezzanine to a library, which is part of a one story school building. The school really wants to glaze the mezzanine wall (rather than having just a railing overlooking the library), so in order to do this, we have to add another means of egress to the mezzanine, which will take the form of an exterior staircase down to the deck outside the library. Does this egress stair have to be covered? See attached image for reference. Thanks!