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.

The amount of force required to use a hand tool and its relationship to the user's capacity to exert this force is a critical design criterion of hand tools, often affecting the immediate safety of the tool user and the propensity of the tool to cause injury to the user with long-term use.wrist is often placed in deviated positions, the available data on grip strength with an undeviated wrist configuration may not be applicable to the design of many hand tools. the decreases in grip strength due to wrist deviations and forearm rotation. The position of maximal static grip strength is the neutral wrist with a supinated forearm. Decrements from the neutral position for wrist flexion, hyperextension, radial flexion and ulnar flexion are 30%, 22%, 18% and 15%, respectively. The pronated forearm allows only 87% of the strength of the supinated forearm, and the differences between the supinated and the midposition forearm are not significant. Because the This study demonstrates INTRODUCTION

No abstract

The forensic area of practice for human factors engineers has brought into sharp focus the differences of opinion which exist regarding the effectiveness of warnings in bringin bout safe behavior on the part of the user of a product. This paper addresses the major issues which the authors believe must be researched further to provide the definitive answers needed regarding the effectiveness of warnings in a variety of possible applications. A review of the literature will demonstrate that there are few studies of warning effectiveness per se, while there are many studies that address such issues as the need for warnings and presumed criteria for preparing effective warnings. It is suggested that further research is needed which addresses warning effectiveness in actual use situations, and in turn identifies the importance of such variables as stimulus energy level, information overload, risk perception, cost of compliance and the interaction of warnings, instructions and training.

No abstract