Coefficient of Friction and Subjective Assessment of Slippery Work Surfaces

Abstract

Research was conducted to determine how well subjects could distinguish between surfaces with different coefficient of friction (COF) values and to evaluate how well subjective ratings of slipperiness correlated with the actual COF values. Thirty-three ironworkers experienced in working and walking on steel surfaces and 23 university students inexperienced with these tasks participated in the study. Subjective slipperiness ratings for a variety of climbing and walking conditions were obtained from the subjects. It was found that subjects could identify differences in the slipperiness of four types of steel coatings tested in the study. There was a high correlation between the subjective ratings and the measured COF values. Subjects did not slip at a COF of 0.41 but did lose footing at a COF of 0.20.

Análisis biomecánico y perceptivo de la movilidad peatonal para fijar límites de seguridad y confort en la fricción de pavimentos urbanos

“…The results of the second phase of this study, in consonance with many authors Swensen et al, 1992; presented a good correlation between measured and perceived friction. The DCOF measured with a vertical force of 200 N, sliding velocity of 0.5 m/s and rubber sole yielded the highest Pearson correlation (r D 0.85) with mean AHP at the same time than a very high repeatability.…”

“…Por otro lado, el resultado de la segunda fase del artículo 1 es totalmente coherente con lo observado por otros autores Swensen et al, 1992) ya que se establece una correlación muy clara entre la fricción dinámica medida y la fricción percibida. El DCOF con una fuerza vertical de 200N, velocidad de deslizamiento de 0.5m/s y probeta de caucho alcanzó la mayor correlación (r=0.85) y repetibilidad con la fricción percibida (AHP mediante el método Saaty).…”

“…Humans have been described to modify walking pattern if a slipping risk is perceived. Literature results show a good correlation between measured and perceived friction Swensen et al, 1992; suggesting that combining subjective evaluation and objective measurements is the best approach to establish friction safety levels . This paper presents the work conducted to Wrst identify the population group with the highest RCOF among people aZicted by diVerent pathologies.…”

Human-centred approaches in slipperiness measurement

“…paired comparisons) have been applied to measure slipperiness. Human subjects seem to be capable of differentiating the slipperiness of floors (Yoshioka et al 1978, 1979, Swensen et al 1992, Myung et al 1993, Chiou et al 1996 and footwear , Tisserand 1985, Nagata 1989 in dry, wet, or contaminated conditions. Cohen and Cohen (1994a, b) pointed out that tactile sliding resistance cues are the most sensitive predictors of the coefficient of friction under various experimental conditions but particularly on wet surfaces.…”

Why walkers slip: Shine is not a reliable cue for slippery ground

“…If alerted three to four steps in advance, walkers can steer sharply (0º-60º) around the low-friction area (Patla, 1989). They can adjust their gait patterns to walk over the surface by slowing down, taking shorter steps, keeping the body stiffly upright, landing flat-footed, and reducing the speed at which the foot moves when the heel contacts the floor and when the toes push off the floor (Cham & Redfern, 2002;Marigold & Patla, 2002;Myung & Smith, 1997;Patla, 1991Patla, , 1997Swensen, Purswell, Schlegel, & Stanevich, 1992). However, without sufficient advance warning, walkers cannot execute their antislip strategies.…”