Analysis and testing of a hidden stepladder hazard - excessive twist flexibility

Accidental falls from stepladders are responsible for tens of thousands of injuries in the US each year. This paper augues recent research concerning excessive stepladder twist flexibility, which can lead to ladder falls. Such falls can easily occur when only three of a ladder's four legs are in contact with the ground and an unknowing climber shifts his weight, causing the ladder's raised leg to move suddenly downward and the climber to lose his balance. The static and dynamic test and analysis results presented show a major cause of this hazard, its effect on climbers and the influence of ladder design on the likelihood of its occurrence. The inadequacy of existing stepladder safety standards to protect against such accidents is noted and a call for a new testing standard is outlined. It would be prudent to develop and implement a new racking test and stiffer ladder twist requirements to reduce the likelihood of inadvertent ladder racking.