IE 366 Chapter 11 Workstation Design

IE 366 Overview ● Workstation design in the work systems engineering process ● Guidelines for workstations for repetitive work (Konz & Johnson, with supplementary information) ● Additional workstation design guidelines

IE 366 Guidelines for the Design of Workstations for Repetitive Work (Konz & Johnson) ● What is a Guideline?

IE 366 Guideline 1 Avoid Static Loads and Fixed Work Postures ● Blood pressure. ● Metabolic wastes. ● Movement. ● Recovery time.

IE 366 Guideline 2 Reduce Musculoskeletal Disorders ● Work height ● Wrist posture. ● Elbow posture. ● Reaching behind back. ● Hand and arm motions.

IE 366 Guideline 3 Set the Work Height at 50 mm Below the Elbow ● Work height. ● Optimum height. ● Sitting vs standing. ● Work height and table height. ● Solutions. ● Considerations

IE 366 VDT Workstations ● Key items. ● Adjustablility. ● Primary visual supremacy. ● Operator training. ● Wrist rests.

IE 366 Guideline 4 Furnish Every Employee with an Adjustable Chair ● Cost considerations. ● Trial runs. ● Adjustability. ● Training. ● Chair design.

IE 366 More on Seating ● Provide lumbar support. ● Back at moderate angle (10° - 30° from vertical). ● Seat pan/back angle 95° - 120°. ● Set seat height for small people. ● Set seat width for large people. ● Provide for adjustability. ● When back support not used, minimize lumbar flexion (higher, forward - sloping seat).

IE 366 Guideline 5 Use the Feet as Well as the Hands ● Leg speed. ● Leg dexterity. ● Leg power. ● Pedals.

IE 366 Guideline 6 Use Gravity; Don’t Oppose It ● Movement direction. ● Lifting. ● Body weight and mechanical force. ● Material handling with gravity. ● Gravity as a fixture. ● Feeding and disposal.

IE 366 Guideline 7 Conserve Momentum ● Acceleration and deceleration. ● Stirring and polishing. ● Follow through. ● Grasping. ● Hand transport.

IE 366 Guideline 8 Use 2-Hand Motions Rather Than 1-Hand Motions ● Cranking. ● Two-hand actions. ● Hand as fixture.

IE 366 Guideline 9 Use Parallel Motions for Eye Control of 2-Hand Motions ● Spread vs symmetry. ● Cost of eye control. BC A D Parallel motions shoulder moves easy eye travel DD C C B B A A Symmetrical motions shoulder steady difficult eye control

IE 366 Guideline 10 Use Rowing Motions for 2-Hand Motions ● Alternation. ● Efficiency and power.

IE 366 Guideline 11 Pivot Motions About the Elbow ● Motion time. ● Cross-body vs elbow movements. ● Physiological cost.

IE 366 Guideline 12 Use the Preferred Hand ● Dominant hand. ● Work arrival.

IE 366 Guideline 13 Keep Arm Motions in the Normal Work Area ● Work benches. ● Material handling equipment. ● High use. ● Arm pivot. ● Shoulder sensitivity.

IE 366 Guideline 14 Let the Small Person Reach; Let the Large Person Fit ● Designing for most of the population. ● Both sexes. ● Multiperson use. ● Civilian ≠ military. ● International populations. ● Excluded proportion.

IE 366 Additional Workstation Design Guidelines

IE 366 Guideline 15 Choose and appropriately design the displays to provide needed information. – text displays – dynamic visual displays – analog displays ● quantitative ● qualitative (check reading) – digital displays – status indicators – auditory displays

IE 366 Guideline 16 Design to overcome the operator’s cognitive limitations. – Working memory limitations – Distraction / interruption – Vigilance – Decision biases – Error vulnerabilities

IE 366 Guideline 17 Design to enhance human motor performance. – Require only reasonable accuracy and speed. – Consider speed/accuracy tradeoff. – Provide appropriate feedback. – Apply appropriate control design/selection principles & guidelines. – Apply appropriate hand tool design/selection principles & guidelines.

IE 366 Guideline 18 Design to enhance cognitive performance. – Consider both novice and expert – Provide adequate training – Provide job performance aids

IE 366 Guideline 19 Design for visibility, accessibility, accommodation, protection. – visibility outside workstation (if appropriate) – visibility inside workstation (displays, controls, etc.) – accessibility of primary controls – accessibility of secondary controls – body member support – body member clearance – clearance for clothing & personal equipment – restraint (if appropriate) – protection from injury – ease, speed, safety of entry & exit – consistency throughout

IE 366 Guideline 20 Arrange the workstation logically. 1.Accommodate primary visual tasks. 2.Place controls for primary visual tasks (next slide). 3.Preserve control / display relationships, e.g., population stereotypes up-increase etc. 4.Arrange by sequence of use. 5.Arrange by frequency of use. 6.Arrange to be consistent with other systems.

IE 366 Car Dashboard Copyright  Sam Chui, used with permission, downloaded from on 29 Nov 05

IE 366 Control Grouping ● Component clusters, spacing between groups ● Borders around groups ● Groups in recessed areas ● Groups in raised areas ● Color or shading around group ● Groups on inclined areas ● Groups on separate modules

IE 366 Guideline 21 (process design) Design for reasonable workload. – Physical workload ● reasonable energy expenditures ● adequate rest ● consider mechanization, automation – Mental workload ● reasonable mental demands ● not too many concurrent tasks ● consider monitoring, decision making, & control automation

IE 366 Guideline 22 Provide a good physical environment. – Provide adequate illumination. – Control temperature. – Control vibration. – Compensate for acceleration.

IE 366 Guideline 23 Provide a safe workstation. – Control hazards: ● chemical ● biological ● radiation ● pressure ● noise ● mechanical ● electrical – Provide fire detection/suppression. – Provide personal protection equipment, as appropriate.

IE 366 Summary ● Workstation design in the work systems engineering process ● Guidelines for workstations for repetitive work (Konz & Johnson, with supplementary information) ● Additional workstation design guidelines