The Slip-resistance Effect Evaluation of Floor Roughness Under Different Liquid Viscosity

Abstract Slipping, tripping and falling which causes serious damages and losses happen all the time within household and work areas. According the formula of squeeze film, when the floor is contaminated with liquid, the higher the liquid viscosity the longer time to connect shoes with floor, the higher the risk of falling. The appropriate roughness of floor surface could be effective to improve the squeeze film effect caused by liquid while the floor is contaminated by liquid or oil. In kitchens, oil, sauces and liquid with higher viscosity are easily spread on floor. Therefore, this study discussed the influences of liquid viscosity and floor roughness upon slip-resistance effect adopting two shoe materials, six liquid with different viscosity and six floors with different roughness. The results demonstrate that the higher the liquid viscosity the lower the coefficient of friction. No matter how rough the floor is, the coefficient of friction approaches zero while the viscosity larger than 38 mPa.s. With the liquid (water or soda) viscosities were lower than 2mPa.s, the slip resistant effect only shown as the floor roughness (Ra) was larger than 28 μm and Rtm was greater than 145 μm. The slip resistant effect shown as the floor roughness (Ra) must be much greater than 40 μm and Rtm must be much higher than 185 μm while the floor contaminated by liquid with viscosities higher than 2mPa.s. Therefore, the best strategy to prevent slips/falls should be keeping the floor dry all the time.