Escape and Fire Staircases – Spiral Staircase

The spiral staircase is a unique design within the family of curved staircases and represents the most space-efficient solution. Its defining feature is the central column, which acts as the load-bearing core of the entire structure.

Spiral staircases are often only mentioned briefly in related technical literature, as there are no specific regulations governing their design. Due to the special shape of the steps, it is essential to differentiate between the nominal tread width (the distance between the central column and the inner edge of the handrail) and the usable tread width (the distance measured from 100 mm beyond the inner edge, in accordance with DIN 18065).

One of the key characteristics of spiral staircases is that the reference point for usable tread width is shifted toward the center of the usable walking surface. The minimum outer diameter of a spiral staircase should be no less than 1300 mm, as any smaller dimension significantly restricts functionality. To achieve a usable tread width of 1000 mm, an approximate outer diameter of 2900 mm is required.

At MEISER, our standard spiral staircases include a central column and corresponding tension rings on each tread. This construction allows us to accommodate a wide variety of design options and customer requirements. We primarily use four pipe combinations, selected based on the staircase height and diameter in line with structural requirements.

In our tension ring system, we offer intermediate rings made from machined steel to cover the gaps between the tension rings. Another possible construction involves dividing the central column by floor level using welded node plates, onto which each step can be bolted. The treads are fixed together using spacer tubes and threaded rods. Railing posts are bolted to every second step.

Spiral staircases designed with vertically aligned exit platforms present a critical challenge when managing level differences of approximately 4000 mm. It is not possible to maintain both safe tread geometry and a clear headroom of 2000 mm at all diameters. Additional safety features—such as handrails surrounding the central column and blocking access at the entrance—can help ensure both safe usage and protection against unauthorized entry.

It is our responsibility to recommend the optimal solution. You can trust in our expertise and service.

Architects’ unique demands repeatedly present new challenges for us to solve while remaining compliant with all applicable standards. In such cases, we are your reliable partner—even for the production of complex welded structures.

MEISER FERROSTE Kft. holds a welding certification in accordance with Table B.1 of EN 1090-1, and a factory production control (FPC) certificate valid up to execution class EXC2 under EN 1090-2 for load-bearing steel structures.

Step depth and riser height must be selected in proportion to the natural human stride. Our experience and accident statistics indicate that an optimal riser height falls between 140 mm and 190 mm, and the tread depth between 260 mm and 320 mm, in line with the following formula:

2 × (s) riser height + (a) tread depth = 630 ± 30 mm

The ideal inclination angle should be between 30° and 45°.

After a maximum of 18 steps per flight, an intermediate or turning platform must be included, where required by building code or use case.

Our spiral staircases are equipped as standard with anti-slip grating inserts (certified GS slip resistance) and are manufactured without protruding front step edges, as the grating is welded into a flat bar frame with straight, uniformly high outer edges. Optionally, a welded-on front safety edge can be added.

It is not always possible to retroactively attach a staircase to every building or to every location within a building. However, our technicians and structural engineers consistently develop customized solutions to ensure the staircase can be safely anchored to the structure. The connection between the staircase and the building is a fundamental element of the structural concept. In close cooperation with our clients, we work to find the best possible solution—one that meets all requirements and complies with both architectural and structural engineering standards.