Stairs spiral model Berlin

Hole in the ceiling - minimum for stairs with a diameter of 160 cm
circle opening 170 cm,
square opening 170x170 cm,
height of the stairs 280.0-322.0 cm (platform flush with the upper floor),
height of the stairs 300.0-345.0 cm (platform below the upper floor),
fixed step height 20.0/23.0 cm,
usable step width 700 mm (between the post and the balustrade),
stair treatment: left or right

Opening in the ceiling - minimum for stairs with a diameter of 170 cm
circle opening 180 cm,
square opening 180x180 cm,
height of the stairs 280.0-322.0 cm (platform flush with the upper floor),
height of the stairs 300.0-345.0 cm (platform below the upper floor),
fixed step height 20.0/23.0 cm,
usable step width 750 mm (between the post and the balustrade),
stair treatment: left or right

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

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

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