Evidence-Based Design Principles for Safer Stairs: The Role of Geometry, Surface Performance, and Visual Definition

Stair-related falls remain a major contributor to slip, trip and fall (STF) incidents across the built environment, representing a significant public health, legal, and economic challenge. Epidemiological data consistently show that stairs are a high-risk transitional element within buildings, with injuries frequently resulting from a combination of geometric inconsistency, inadequate visual definition, insufficient slip resistance, and suboptimal user support.

This paper synthesises established research, regulatory guidance, and applied industry knowledge to examine the principal design and specification factors that influence stair safety in non-domestic internal environments. Five interdependent elements are evaluated: (i) step geometry, with particular focus on rise, going, and dimensional consistency; (ii) proprietary stair nosings, including their geometry, positioning, visual contrast, and slip resistance performance; (iii) handrail provision, continuity, and ergonomics; (iv) lighting quality and distribution; and (v) cleaning, inspection, and maintenance regimes.

The analysis highlights the disproportionate effect that small variations in step dimensions can have on gait, foot placement, and misstep frequency, particularly during descent. It further demonstrates how correctly specified stair nosings—designed to clearly define the step edge while providing adequate slip resistance at the point of foot contact—play a critical role in risk mitigation. The paper also examines the application of Light Reflectance Values (LRVs) to improve visual contrast, alongside accepted laboratory and in-situ methods for assessing slip resistance performance.

By consolidating evidence from ergonomics, human factors research, and building standards into a practical framework, this paper aims to support more consistent and informed stair design, refurbishment, and product specification. While acknowledging that no stair can ever be entirely free from risk, it is argued that systematic attention to these five factors can significantly reduce the likelihood and severity of stair-related accidents, contributing to safer, more inclusive building environments.