Designations and terms

The definition of terms is based on DIN 18065 (Building stairways). For further terms please refer to the standard.

1. Going [a]	2. Toe space [u]
3. Rise [s]	4. Step spacing
5. Flight length	6. Stairway flight
7. Stairway landing, intermediate landing, ceiling	8. First step
9. Step	10. Riser
11. Last step	12. Tread surface
13. Top inset	14. Bottom inset

The first step is defined as the first (lowermost) step of a flight of steps after leaving the story level. The first step may be a constituent part of the stairway or of the story level.

The going is the horizontal measurement of the tread surface extending from the front edge of a step to the projection of the front edge of the following step.

The last step is designated as the last (uppermost) step of a flight of steps, which may also be part of the top landing. The last step is therefore either a constructional part of the stairway and connects to the story level at the same height or it is a constructional part of the story level.

The comfort is calculated as the going minus rise and should be about 12 cm (a-s=12cm).

Distance of the front edge of a tread to the top edge of the string (top inset) or from the rear edge of a tread to the bottom inset of the string (bottom inset).

The sure-footed safety is calculated as the going plus the rise and should be about 46 cm (a+s=46cm).

The walking line is an imaginary line indicating the normal path taken by a user of a stairway. It lies in the walking area of the stairway plan.

The slope of the stairway is the angle between the imaginary line connecting the front edges of the treads and the horizontal. It is given by the rise-to-going ratio (rise/going).

The step length (step proportion) is calculated from twice the rise plus going and should ideally be 63 cm to 65 cm (2s+a= 63 cm to 65 cm).

The riser is a perpendicular or almost perpendicular part of the step.

The rise is the perpendicular distance measured from the tread surface of a step to the tread surface of the following step.

The rise-to-going ratio is the quotient of the rise over going. It gives the slope of the stairway.

Winding is the technical term for the course of the spiral steps of a stairway. For the winding of the steps many different projection methods have arisen in the course of centuries. The result of good winding should however always be a comfortable and safe stairway, taking into account the step-length rules and the requirements of building legislation.

The stairwell is the air space in the center of a stairway system. The stairwell is the free space enclosed by the flights, landings and banisters.

The tread is the horizontal part of the step.

The toe space is the horizontal measurement by which the front edge of a step protrudes over the width of the tread of the step below.