# Calculating the size of a spiral staircase

drawing scale 1:

Specify dimensions in millimetres

The height of the stairs H
Diameter of stair D1
Internal diameter D2
Angle of rotation A

Number of steps C
The thickness of the treads Z

## Calculation of spiral stairs

Enter the required dimensions

H - The height of the stairs
D1 - outer diameter
D2 - Internal diameter
C - Number of steps
Z - The thickness of the treads
A - The rotation angle of the stairs

## Help

The length of steps in the spiral staircases should not be less than 80 cm
Step width in the central part should not be less than 20-25 cm at the widest part - nor more than 40 cm. Spiral staircase step height can be greater than the height recommended for mid-flight of stairs. Normal step height for straight stairs is 16 cm, for spiral stairs - 18 cm

In the place where the leg begins, step spiral staircase to be about 25-30 cm, on the edge - not less than 30-35 cm. The depth level is quite convenient. Then foot man will be on stage in full, not hanging over the edge.

Step size spiral staircases.

h - length of the stage
W1 - step width in the widest part of
W2 - width of the workpiece stage
α - bank angle step

Author of the project: Dmitry Zhitov