Volume 24, Issue 6 (November 1996)
Surface Roughness of Footwear Soling Materials: Relevance to Slip Resistance
The slip resistance of commercial safety boot and experimental footwear solings has been studied over a period of 15 years. Shoes, with experimental solings, were worn in a factory, and the coefficient of friction (CoF) measured at intervals, using a walking traction test. These measurements have shown that a microcellular polyurethane, AP66033 (formerly T66/103) gives the greatest slip resistance of any soling material on wet or oily factory floors and laboratory test surfaces. This performance is attributed to the statistically significant relationship between CoF and mean peak to trough roughness (Rtm). The surface structure of soling materials was examined using Scanning Electron Microscopy, and images compared with Rtm measurements. There is now sufficient experimental evidence to confirm that surface roughness is one of the determinants of CoF on lubricated floors. The wear characteristics of the floor/sole combination must be considered: some soling materials may become polished on certain floors. However, AP66033 cannot be polished.