Final Exit doors don't have to be fire rated if they are from protected shafts, often they are fully glazed. Only the doors onto staircases, protected areas, high risk rooms, or in compartment or separating walls etc need to be rated, in line with your fire strategy. Widths should be calculated or checked for exit capacity. Standard sizes are 1980 x 826 and 926 or imperial equivalents, narrower widths eg 750 are used for some domestic and rehab work. Much wider and they are better as leaf and a half or double doors 1500 - 1800. Many need safety glass vision panels so are usually to order and you need seals as per regulations. Fire doors should be self closing, and door leaves need to be 44 mm or thicker depending on fire rating. Frames must be properly designed, with 50 x 25 mm planted stops, or worked from the solid. If doors are routinely used by people in wheelchairs that becomes the determining factor rather than the exit capacity for width of door leaves. Any sort of key operation from escape side is not permissible.