Industrial Ergonomics Unit 2 Flashcards
Manual Material Handling
Is the act of manually grasping and moving an object of a definable size
Psychophysical methods in MMH
Are a formalized way of subjectively determining maximum acceptable loads for a prolonged period of time
Borg Scales
Borg 6-20: Whole body efforts, global
Borg 0-10: % of muscular strength, local
The criterion (at risk) level for a compressive force at the L5S1 joint is
3400N
Maximum Aerobic Capacity
The maximum rate at which your body can use oxygen to generate chemical energy for your body to use
Psychophysical Criterion
A criterion acceptable to 75% of female workers will be acceptable to approximately 99% of male workers
Lifting Equation
RWL= LC x HM x VM x DM x AM x FM x CM LC= lifting constant
Lift Index
Actual Load/RWL
NIOSH Lifting Equation Assumptions and Limitations
Does not include MMH activities other than lifting
Assumes lifting task is two-handed, smooth, in front of the body, hands at the same height, moderate-width loads
Biomechanical criterion focuses only on low back loads
Assumes that lifting and lowering have the same level of risk
Good coefficient of friction between the shoes and the work surface
The General Duty Clause
States employers are required to provide their employees with a place of employment that is “free from recognized hazards that are causing or are likely to cause death or serious physical harm
WISHA Lifting Calculator
Washington Industrial Safety and Health Act
Hierarchy of Controls
Elimination Substitution Engineering Controls Administrative Controls PPE
Abdominal Belts as an Engineering Control
Studies have reported belt use to:
reduce low back injury rate
increase intra-abdominal pressure
reduce spinal shrinkage
Potential negative side effects of belt use include: Deconditioning of trunk musculature
Increased risk of herniation
Increased sense of security causes workers to take unnecessary risks
Examples of administrative controls for MMH
Scheduling: Work-rest scheduling Work rotation between different work tasks Training (two general types): Training to reduce task demands Training to increase worker capacity
Lift Technique Training as an Administrative Control
Although numerous studies have compared these two techniques, the evidence to support squat lifting is weak
Worker Selection as an Administrative Control
Worker Selection:
select the most appropriate workers for a specific job
How to design MMH tasks to be safe?
The best way to reduce WMSDs during MMH is to use well-designed tasks and work stations(that have few/no job-related risk factors and minimize MMH demands)
Example of applying knowledge of risk factors for designing an MMH task
Task-Related Risk Factors (tend to have a large effect on risk) Individual Characteristics (tend to have a moderate effect on risk)
Epidemiology
The study of the frequency, distribution, risk factors, and possible control of health problems
Measures of Injury or Disease Frequency
Incidence: number of individuals who develop an injury or disease during a period of time within a population at risk
Prevalence: number of individuals who have an injury or disease during a period of time, or at a point in time
Measures of Exposure-Injury Association
Relative Risk (RR) Odds Ratio (OR)
Relative risk
A ratio of two probabilities (or risk)
Risk in an exposed group divided by risk in an unexposed group
Odds Ratio
A ratio of two odds
The odds of an event (injury) is the number of events/number of non-events
Pitfalls and Precautions of RR and OR
Healthy worker survivor effect
Sampling Variability
Confounding variables
Hawthorne Effect
Checklists
Provide rapid initial evaluation of jobs to prior to more complex job analysis
Help identify risk factors and jobs needing high priority interventions
OSHA’s Ergonomics Assessment Checklist
General took that evaluates several workplace risk factors
High repetition, High force exertions, Awkward/extreme postures, Contact mechanical stress, Vibration
Rapid Upper Limb Assessment (RULA)
A survey method for ergonomic investigation where upper limb disorders are of concern
Analyzes posture at a moment in the work cycle
Rapid Entire Body Assessment (REBA)
Designed to assess working postures found in health care and other service industries
As with RULA, REBA analyzes a moment in the work cycle
Strain Index
Is a tool used to evaluate the risk of developing a WMSD in the hand, wrist, forearm, or elbow
