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Developing a Method for the Design and Evaluation of Manual Lifting Tasks. National Institute for Occupational Safety and Health (NIOSH). 1981 committee met to recommend criteria for defining lifting capacity evaluate lifting demands . NIOSH Lifting Equation. Criteria: 1. Biomechanical
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Developing a Method for the Design and Evaluation of Manual Lifting Tasks
National Institute for Occupational Safety and Health (NIOSH) • 1981 • committee met to recommend criteria for defining lifting capacity • evaluate lifting demands
NIOSH Lifting Equation Criteria: 1. Biomechanical - loading of the spine 2. Physiological - energy expenditure 3. Psychophysical - capacity to lift
NIOSH Lifting Equation Goal: • Identify ergonomic solutions for reducing physical stresses • 1991 revised version
Activity • Keeping in mind the goal (and criteria) of the NIOSH committee • Identify features/factors of a lifting task that contribute the most to the hazard of low back injuries
Revised NIOSH Lifting Equation (1991) • Lifting equation for calculating the Recommended Weight Limit (RWL) • represents a load nearly all healthy workers could perform (up to 8 hrs.) w/o risk of developing lifting-related LBP
RWL RWL = LC x HM x VM x DM x AM x FM x CM • LC = 51 lbs. • HM = horizontal (initial horizontal position) • VM = vertical (initial vertical position) • DM = distance (total vertical distance moved) • AM = asymmetric • FM = frequency • CM = coupling
RWL RWL = LC x HM x VM x DM x AM x FM x CM • LC = 51 lbs. • HM = 10/H • VM = 1 - (.0075|V - 30|) • DM = 0.82 - (1.8/D) • AM = 1 - (.0032 * A) • FM = Table • CM = Table
Lifting Index (LI) • Ratio or comparison between actual weight lifted (L) and RWL • LI = Load Weight / RWL • Relative index of physical stress