New building code restriction: openings in exterior walls within 3 meters horizontally and less than 5 meters above unenclosed exterior exit stairs or ramps need to be fire protected
Spiral Stair install - 25'9" - 3 landings with outer handrail 1070mm high, clear width between handrails 660mm, risers not more than 240mm, minimum of 190mm deep run at 300 mm from center line of handrail - Gerrard