Effect of side forces on the stability of scissor lifts.
Pan-C; Chiou-S; Powers-J; Cantis-D; Ronaghi-M; Boehler-B
NOIRS 2008-Abstracts of the National Occupational Injury Research Symposium, October 21-23, 2008, Pittsburgh, Pennsylvania. Morgantown, WV: National Institute for Occupational Safety and Health, 2008 Oct; :B1.3
Construction work is one of the leading fatal occupations. Seventy-four percent of scissor lift fatalities occurred in the construction industry. Previous research evidence indicates that falls were major causes of fatalities related to scissor lifts. In addition, constructing and repairing activities contributed to almost half of scissor lift falls. Operator activities within the platform, such as pushing a drill and pulling wires, create excessive side forces leading to the instability of scissor lifts. The objective of this study was to examine the effect of side forces generated by operator activities on the overall stability of scissor lifts. Twenty construction workers (mean age: 42.3 +/- 7.7 years) participated in this study. Maximum side forces were measured while subjects performed simulated construction tasks on the main or extension platform in three standing directions. The experiments were conducted at three levels of lift heights (39, 56, or 72 inches). Three accelerometers were attached underneath the scissor lift to simultaneously determine the lift stability. The greatest side force observed among 1,080 trials was 140.85 lbs. Results from repeated-measure ANOVAs revealed that the height of the scissor lift did not affect the maximum side forces exerted by the subjects, implying high side forces may occur at any level of height. Pushing tasks produced significantly greater side forces than pulling tasks (p < 0.0001). Tasks performed in a standing direction parallel with the length of the lift created the greatest side forces (p < 0.0001). Significantly greater lift acceleration was also found while subjects performed tasks in the direction parallel with the lift at either 56 or 72 inches of height. This study provides important information on the magnitudes of side forces generated by operators as well as how standing directions affect side forces and the stability of scissor lifts.
Accident-prevention; Accidents; Construction-equipment; Construction-industry; Construction-workers; Control-technology; Engineering-controls; Equipment-reliability; Force; Injuries; Injury-prevention; Traumatic-injuries; Workplace-studies
NOIRS 2008-Abstracts of the National Occupational Injury Research Symposium, October 21-23, 2008, Pittsburgh, Pennsylvania