ASU Study Targets Outdated Bathroom Safety Standard to Curb Falls

As Falls Prevention Awareness Week spotlights the dangers of slips and tumbles — particularly for older adults — researchers at Arizona State University are working to make one of the home's most hazardous rooms safer.

ASU has partnered with the U.S. Consumer Product Safety Commission on a large study aimed at developing standards for bathroom surfaces such as shower stalls and bathtubs. At the centre of the effort is the surface friction standard, a measure of how slippery a tub or bathroom floor may be. According to ASU's Thurmon Lockhart, that standard has been obsolete since 1978, leaving manufacturers of flooring and bathroom fixtures without a benchmark — and architects who design bathrooms in homes, apartments and hotels without guidance.

The research examines how falls occur both while stepping into and stepping out of tubs and other surfaces. In the study, older adult volunteers strap into a safety harness and step onto slippery surfaces while high-speed cameras capture and map their body movements. Tests will be conducted with and without safety hand rails, and the project will eventually involve hundreds of volunteers.

Lockhart, a professor in ASU's School of Biological and Health Systems Engineering, said the risks extend well beyond broken bones. He noted that while traumatic brain injury is often associated with athletes, statistics show that the majority of such injuries occur in older adults and are linked to bathtub-related accidents.

The research also seeks to explain why older adults fall more often than younger people. Lockhart attributes the difference to sensory degradation that comes with ageing — declines in vision, the vestibular system and proprioception. He explained that a slip occurs when the friction a person demands exceeds what the surface provides. A younger person may demand a coefficient of friction of about 0.2, while soapy water can reduce the available friction to roughly 0.10, making a slip inevitable. Older adults, he said, tend to have a higher friction demand, which may explain their greater risk.

The scale of the problem is significant. The Consumer Product Safety Commission estimates that Americans experience about 12 million falls each year. With the nation's population ageing, the Centers for Disease Control and Prevention projects that annual falls will reach 52 million by 2030.

Lockhart said the goal is to understand the mechanisms behind slips and falls involving bathtubs and to develop an intervention that can reduce such injuries. Without action, he warned, the coming decades will bring a substantial rise in these accidents as the older population grows.