Correlation of Subjective Slipperiness Judgments with Quantitative COF Measurements for Structural Steel.
School of Industrial Engineering, Institute for Safety and Ergonomics Studies, University of Oklahoma, Norman, Oklahoma 1988 Jun:203 pages
When there is no simple or accurate procedure for measuring the coefficient of friction (COF) at a job site, workers and/or supervisors involved must make subjective judgments about the slipperiness of the walking and climbing surfaces and in turn decide whether the surface presents a safe or an unsafe condition for work. This project was designed to determine whether these subjective judgment calls did in fact agree with the COF measurements obtained using a mechanical device. The authors noted that the coatings chosen for study were subject to a polishing factor by the boot soles during the trials, causing the COF values to become lower as the trials continued. Poor correlation was obtained between subjective ratings of slipperiness and the COF values measured before the trials began. A relatively high correlation was obtained between subjective ratings and the COF values measured after the trials had been completed. A significant difference was noted for the subject ratings for each coating evaluated, suggesting that subjects can distinguish the difference in slipperiness of different types of coatings. A difference was noted in the subjective ratings for the effects of water on a coating for column climbing, but not for walking a beam, suggesting the effects of water on a coating are related to the type of task being performed in steel erection. An increase in the measured COF was noted for all of the coatings when they were wet as compared to the dry condition. Due to the technique used by most of the subjects to climb a column, the primary variable of interest in future studies should be the COF for boot sole material and a given coating/condition, rather than the COF for leather or various types of clothing. The importance of clean shoe soles was clearly demonstrated.
NIOSH-Contract; Contract-200-86-2929; Construction-industry; Safety-research; Accident-prevention; Industrial-safety; Safety-clothing; Footwear; Safety-engineering;
NTIS Accession No.
School of Industrial Engineering, Institute for Safety and Ergonomics Studies, University of Oklahoma, Norman, Oklahoma