Stairs spiral

Opening in the ceiling - minimum for stairs with a diameter of 180 cm
circle opening 190 cm,
square opening 190x190 cm,
stair height 280.0-322.0 cm (platform flush with the upper floor),
stair height 300.0-345.0 cm (landing below the upper floor),
fixed step height 20.0/23.0 cm,
usable step width 800 mm (between the pole and the balustrade),
stairs: left or right

Opening in the ceiling - minimum for stairs with a diameter of 190 cm
circle opening 200 cm,
square opening 200x200 cm,
stair height 280.0-322.0 cm (platform flush with the upper floor),
stair height 300.0-345.0 cm (landing below the upper floor),
fixed step height 20.0/23.0 cm,
usable step width 850 mm (between the pole and the balustrade),
stairs: left or right

Opening in the ceiling - minimum for stairs with a diameter of 200 cm
circle opening 210 cm,
square opening 210x210 cm,
stair height 280.0-322.0 cm (platform flush with the upper floor),
stair height 300.0-345.0 cm (landing below the upper floor),
fixed step height 20.0/23.0 cm,
usable step width 900 mm (between the column and the balustrade),
stairs: left or right