CES Industrial & Manual Handling Ergonomics 1 — Questions and Answers
Question 1: According to the revised NIOSH Lifting Equation, what is the load constant (maximum RWL) under ideal lifting conditions?
- 51 pounds (23 kg) (Correct answer)
- 35 pounds (16 kg)
- 75 pounds (34 kg)
- 25 pounds (11 kg)
Correct answer: 51 pounds (23 kg)
Under ideal conditions where all multipliers equal 1.0, the NIOSH load constant is 51 lbs (23 kg), representing the maximum safe lift achievable in the best possible scenario.
Question 2: Which job factor in the Strain Index (SI) is weighted most heavily in calculating MSD risk for distal upper extremity tasks?
- Intensity of exertion (Correct answer)
- Duration of task per day
- Posture of the wrist and forearm
- Speed of work
Correct answer: Intensity of exertion
In the Strain Index, intensity of exertion carries the highest weight because force demands on tendons and muscles most strongly predict cumulative trauma to the distal upper extremity.
Question 3: What is the recommended maximum initial pushing force for a loaded cart on a level surface for male workers per Liberty Mutual tables?
- Approximately 50 lbs (222 N) for initial force (Correct answer)
- 100 lbs sustained throughout the push
- 25 lbs at all times regardless of surface
- Any force up to the worker's maximum voluntary capacity
Correct answer: Approximately 50 lbs (222 N) for initial force
Liberty Mutual Manual Material Handling Tables indicate approximately 50 lbs as an acceptable initial push force for most male workers on level surfaces, with lower sustained force limits.
Question 4: Which ergonomic control most effectively reduces the risk of back injury during palletizing tasks?
- Installing a pallet turntable and scissor lift table to keep loads at waist height (Correct answer)
- Training workers on proper lifting technique only
- Requiring workers to wear back support belts
- Reducing pallet height limits by 10%
Correct answer: Installing a pallet turntable and scissor lift table to keep loads at waist height
Scissor lift tables and turntables eliminate extreme trunk flexion and trunk rotation, addressing the primary biomechanical hazards of palletizing tasks.
Question 5: What is 'team lifting' and when is it recommended as a control measure?
- Two or more workers sharing a load too heavy or awkward for one person, used when engineering controls are unavailable (Correct answer)
- A training exercise for new employees
- Required for all lifts exceeding 10 lbs
- A technique requiring specialized certification
Correct answer: Two or more workers sharing a load too heavy or awkward for one person, used when engineering controls are unavailable
Team lifting divides load weight between workers when the object exceeds safe single-person limits or is too bulky to handle alone, and is used when equipment-based solutions are not feasible.
Question 6: Which handle design feature most reduces grip force requirements for industrial hand tools?
- Handle diameter matched to the worker's hand size (approximately 1.25-1.75 inches for most adults) (Correct answer)
- Maximum handle length possible
- Smooth, polished handle surfaces
- Square cross-section handles
Correct answer: Handle diameter matched to the worker's hand size (approximately 1.25-1.75 inches for most adults)
Handle diameter matched to the hand allows maximum grip force generation with minimum muscular effort; too small or too large a diameter reduces mechanical advantage and increases exertion.
CES Industrial & Manual Handling Ergonomics 1
According to the revised NIOSH Lifting Equation, what is the load constant (maximum RWL) under ideal lifting conditions?