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Stair Safety Overview - Number of steps

Find out how to reduce the risk of stair falls by reading our article on the importance of the design factor when it comes to the number of stairs needed.

The number of steps and risers is an important design factor that affects fall risk on stairs. The BCA requires that for each flight, (that part of a stair that has a continuous series of risers), have not more than 18 or less than 2 risers. Research has shown that stair falls occur disproportionately to the number of risers. That is, probability of fall accident decreases with the length of flight. According to one source, 30 percent of accidents took place in one or two riser stairways. AS4226 requires that the number of risers should be no fewer than three.

High fall incidence in a short flight is due to the lack of visual cues which indicate changes in elevation. Pedestrians are not able to adjust their gait to the unexpected change in surface conditions, and thus the use of ramp is recommended instead of one step risers wherever possible. AS4226 also recommends changes in colour or light intensity, changes in wall or floor finishes, or the presence of handrail to obtain contrast for better visibility.


Jung, Y. M. & Bridge, C. (2009). Stairs - Summary bulletin. Sydney: Home Modification Information Clearinghouse, University of New South Wales. November 2009 [online]. Available from

Published on: 03-Aug-2010. Topic/s: Stair safety, compliance, and regulations