Revista de Ergonomía
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abstracto

An Analysis of Walkway Surface Micro Roughness and its Impact on Human Slip Potential

Anthony Marletta, PhD, CSP*

The purpose of this study was to analyze three different floor surfaces (ceramic tile with a polished finish, ceramic tile with a matte finish, and a porcelain enamel bathing surface) with varying degrees of floor surface microroughness measured in both the Rz and Ra roughness parameters to identify relative safety thresholds for various floor surfaces. Porcelain enamel and ceramic surfaces were sandblasted to systematically alter the microroughness on the surface samples. Twelve different surfaces were generated under the sand blasting process, with each sample type having four different levels of surface microroughness as measured by a stylus profilometer in both Ra and Rz parameters. This created 15 different surfaces in total to be measured by three tribometers (BOT 3000E, English XL VIT, and Slip-Test Mark IIIB) with four tribometer users. The surfaces were then measured by the tribometers to calculate available friction on each of the surfaces. Only surface microroughness Ra and Rz parameters were found to be significant predictors of available friction on all surfaces measured by all three tribometers (p-value < .001). The predictor surface roughness (Rz) was able to explain 56% of the variability in available friction measured by the Mark IIIB and 43% of the variability in available friction measured by the BOT 3000E. The predictor surface roughness (Ra) was able to explain 82% of the variability in available friction measured by the English XL. This furthers the use of surface microroughness parameters Ra and Rz as a relative means for predicting available friction. The results from this study also indicated surface roughness relative safety threshold guidance varied for each of the three surface types assessed. While there are limitations to tribometer measurement and surface microroughness measurement, these methods have been correlated as a unique individual indicator for slip risk prediction. With each method for assessment having varying degrees of precision and error, the use of these varying techniques can be applied generally as complementary methods for a more comprehensive assessment of walkway surface slip risk.