Repeatability and reproducibility in walkway-safety tribometry : Abrasive-grit size in test-foot preparation

To reduce slips and falls there is a need for repeatable and reproducible measurement, under both field and laboratory conditions, of the slip resistance between pedestrian shoe bottoms and the surfaces involved in human locomotion. Improvement of repeatability (within laboratory) and reproducibility (between laboratories) of portable tribometer test results should be a goal of tribometer designers. This paper reviews the background of advances in friction-related knowledge applicable to improving the repeatability and reproducibility in walkway-safety tribometry. It explores the use of the scanning electron microscope and the coherent-light profilometer to define morphological differences between Neolite® Test Liner and Standard Leather test feet sanded with two different abrasive-paper grits and worn shoe-bottom surfaces composed of the same materials. The experimental method and results are discussed, as is the significance of the findings. Also discussed is the issue of abrasive-paper grit size and its effect on tribometric test results. The paper suggests directions for further research.