Slip-resistance on icy surfaces of shoes, crampons and chains — A new machine

Bruce, M., Jones, C. and Manning, D.P., 1986. Slip-resistance on icy surfaces of shoes, crampons and chains — a new machine. Journal of Occupational Accidents, 7: 273–283. A new machine for measuring friction of shoe solings is described. Shoes and attachments such as crampons and chains worn by a test subject are dragged across the substrate, the horizontal force being measured by a load cell. The machine was used to measure coefficient of friction (COF) on ice and was capable of discriminating between very low friction readings. There was good correlation between the horizontal force recorded by two test subjects using the same shoes. There was also a good correlation between hardness of solings and friction. The highest friction values were generated by the softest materials. It is likely that on ice the optimum hardness is in the range 20 to 30 Shore A. Friction of the worst solings was half the value of the best and it should therefore be possible to reduce accidents on ice by specifying the softest solings. Nevertheless, friction from solings cannot be expected to give complete protection from slipping accidents on smooth ice and only crampons give adequate friction values. Chains attached to shoes have been found to be dangerous on smooth ice.