Slip resistance versus surface roughness of deck and other underfoot surfaces in ships

The slip resistance of thirteen deck and other underfoot surfaces commonly used in ships was assessed by measuring the kinetic coefficient of friction between these floorings, contaminated with glycerol, and three types of safety footwear. The floorings were used on decks, stairs and passages as well as in engine-rooms, kitchens and other indoor and outdoor facilities. The kinetic coefficient of friction (μ_k1) was measured with a prototype apparatus, which simulates the movements of a human foot and the forces applied to the underfoot surface during a sudden slip on the heel.

The measured average μ_k1s of the assessed floorings varied from 0.05 to 0.64. Four floorings were classified as very slip-resistant and one as slip-resistant. All the others were classified as slippery. The rough floorings were more slip-resistant than the smooth ones. The correlation between the arithmetical average roughness (R_a) and the average μ_k1 of the assessed surfaces was very significant (p < 0.001). When selecting deck and other underfoot surfaces and developing new flooring products, more attention should be paid to their surface texture. From the slip resistance point of view the adequate R_a value was 7–9 μm, so smoother surfaces should be avoided. A raised-pattern on floorings also improved the slip resistance compared to corresponding unpatterned floorings.