How to build environments that reduce staircase injuries

As research drives new ways to build staircases that can prevent slip-and-falls, Canada’s building codes should be updated accordingly to reflect the safer designs.

The importance of code updates is illustrated by falls on stairs, which in Ontario alone led to nearly 25,000 emergency room visits for seniors between 2014 and 2015. Falls account for about $8.6 billion in direct and indirect costs every year, according to the Public Health Agency of Canada.

When people fall, it’s important to consider two things: How were they using the environment when the fall took place, and where were they within the environment itself? (Put another way, what were they doing, and where and how were they doing it?)

Currently, four provinces — Alberta, British Columbia, Ontario and Quebec — have their own building codes that standardize building design and construction. The remaining provinces and territories have adopted the National Building Code of Canada (NBCC).

Building codes are regularly revised to create safer built environments, but those revisions don’t apply retroactively unless an existing structure undergoes extensive renovations. This means older buildings often include construction methods that wouldn’t be allowed in newer structures.

As new research becomes available, revisions to older codes are critical.

Stepping up

One key example is stair tread depths, which have changed over time to improve safety.

Older Canadian building codes generally permitted a minimum stair tread depth of 235 millimetres in houses. But research shows the likelihood of falls decreases significantly when tread depths are increased to 255 mms or more.

Building codes have been revised in response. Current versions of the NBCC, Ontario Building Code (OBC) and B.C. Building Code (BCBC) all require at least 255 mms of tread depth.

Evolution in variability of step dimensions is also making things safer for pedestrians.

Canadian building codes have always required uniformity for risers and treads on any one stairway. But since earlier codes didn’t specify what ‘uniformity’ meant, they inadvertently implied that normal construction tolerances were acceptable.

Newer versions of Canadian building codes have established numerical tolerances for uniformity. For example, the current OBC and BCBC only allow a difference of five mms between adjacent staircase risers and treads.

Research also shows foot clearances are lowest in the middle of stairways when compared to the transitions onto and off stairways. This is due to the way people’s bodies move when entering a repeatable and predictable pattern.

So, while variability poses degrees of risk to a person’s balance depending on where it takes place on a stairway, the more stringent uniformity requirements in the latest Canadian building codes help address this concern.

Hang on

Another aspect of stair evolution is handrail heights.

Earlier building codes typically allowed handrails in publicly accessible buildings to be between 813 mms and 914 mms high. Yet research on the use of taller handrails shows physical demands on people’s bodies decrease as handrail heights increase. What’s more, stairway users can withstand larger disturbances to their balance when a railing is higher.

In other words, increasing handrail height reduces the fall risk for pedestrians on stairways. Canadian building codes have been revised based on this research, and the OBC and BCBC now allow handrails to be as tall as 1,070 mms.

While these changes are great examples of how updating requirements for the built environment can help decrease the risk of falls, building codes generally aren’t applied retroactively. It’s not cost-effective, and sometimes not feasible, to update or renovate older buildings to meet newer requirements.

Going forward, it’s important we keep both the mechanics of falling and the built environment in mind when trying to understand how and why people fall. As our population ages, building code updates must keep pace with the science, so that structures continually become safer to use.

Dr. Andrew Huntley is an associate, biomechanics and personal injury, and Claire Miller is an associate, civil/structural and building science at 30 Forensic Engineering. This story is excerpted from one that appeared in the October print edition of Canadian Underwriter. Feature image by iStock.com/AndreyPopov