CES Manual Material Handling & Industrial Ergonomics 1 — Questions and Answers
Question 1: In the NIOSH Revised Lifting Equation (1994), what is the Recommended Weight Limit (RWL) used to calculate?
- Maximum force a worker should ever exert
- A weight limit specific to the task conditions that protects most healthy workers (Correct answer)
- The legal weight limit per OSHA standards
- Average weight lifted across a shift
Correct answer: A weight limit specific to the task conditions that protects most healthy workers
The RWL is the task-specific maximum load weight that protects approximately 75% of male and 99% of female workers from excessive spinal compression.
Question 2: The Lifting Index (LI) is calculated as:
- RWL divided by actual load weight
- Actual load weight divided by RWL (Correct answer)
- Load weight multiplied by frequency
- Horizontal distance divided by vertical height
Correct answer: Actual load weight divided by RWL
LI = Load Weight / RWL; an LI greater than 1.0 indicates increasing risk and a value above 3.0 represents high risk requiring immediate intervention.
Question 3: Which factor in the NIOSH Lifting Equation penalizes lifts that involve significant twisting of the torso?
- Horizontal Multiplier (HM)
- Asymmetry Multiplier (AM) (Correct answer)
- Frequency Multiplier (FM)
- Coupling Multiplier (CM)
Correct answer: Asymmetry Multiplier (AM)
The Asymmetry Multiplier (AM) reduces the RWL when there is angular displacement of the load from the sagittal (front) plane, penalizing torso twisting.
Question 4: What is the primary purpose of a 'team lift' protocol?
- To increase speed of material handling
- To distribute the load so no single worker exceeds individual capacity (Correct answer)
- To comply with union agreements
- To reduce the number of lifts per day
Correct answer: To distribute the load so no single worker exceeds individual capacity
Team lifts distribute heavy or bulky loads among two or more workers so that each person's share remains within safe individual lifting limits.
Question 5: Which pushing/pulling measurement tool is most commonly used to assess force limits in industrial settings?
- Goniometer
- Dynamometer or force gauge (Correct answer)
- Inclinometer
- Borg RPE scale
Correct answer: Dynamometer or force gauge
A dynamometer or force gauge measures the initial and sustained push/pull forces applied to carts or equipment, which are then compared to Snook tables or Liberty Mutual guidelines.
Question 6: Conveyor height for repetitive assembly tasks should ideally be set at:
- Floor level
- Knee height
- Elbow height of the standing worker (Correct answer)
- Shoulder height
Correct answer: Elbow height of the standing worker
Setting conveyor or work surface height at elbow level minimizes shoulder elevation and allows the arms to work in a neutral, low-load zone.
CES Manual Material Handling & Industrial Ergonomics 1
In the NIOSH Revised Lifting Equation (1994), what is the Recommended Weight Limit (RWL) used to calculate?