Table Of Contentch00_FM_8129_Lehto_LEA 7/2/07 9:36 AM Page i
INTRODUCTION
TO HUMAN FACTORS
AND ERGONOMICS
FOR ENGINEERS
ch00_FM_8129_Lehto_LEA 7/2/07 9:36 AM Page ii
HUMAN FACTORS AND ERGONOMICS
Gavriel Salvendy, Series Editor
Aykin, N.,(Ed.): Usability and Internationalization of Information Technology.
Bagnara, S. (Ed): Theories and Practice in Interaction Design
Carayon, P. (Ed): Handbook of Human Factors and Ergonomics in Health Care and Patient Safety
Hendrick, H., and Kleiner, B.(Eds.): Macroergonomics: Theory, Methods and Applications.
Hollnagel, E. (Ed.): Handbook of Cognitive Task Design.
Jacko, J.A., and Sears, A.(Eds.): The Human-Computer Interaction Handbook: Fundamentals, Evolving
Technologies and Emerging Applications. (See 2nd edition under Sears.)
Karwowski, W.,(Ed.): Handbook of Standards and Guidelines in Ergonomics and Human Factors.
Keates, S., (Au): Designing for Accessibility: A Business Guide to Countering Design Exclusion
Lehto, M. R , and Buck, J.R., (Au):Introduction to Human Factors and Ergonomics for Engineers
Meister, D., (Au.): Conceptual Foundations of Human Factors Measurement.
Meister, D., and Enderwick, T. (Eds.):Human Factors in System Design, Development, and Testing.
Proctor, R., and Vu, K. (Eds.)Handbook of Human Factors in Web Design.
Sears, A. and Jacko, J. A. (Eds.): The Human-Computer Interaction Handbook: Fundamentals,
Evolving Technologies, and Emerging Applications, 2nd Edition.
Stanney, K. (Ed.): Handbook of Virtual Environments: Design, Implementation, and Applications.
Stephanidis, C. (Ed.): User Interfaces for All: Concepts, Methods, and Tools.
Wogalter, M. (Eds.):Handbook of Warnings.
Ye, N. (Ed.): The Handbook of Data Mining.
ALSO IN THIS SERIES
HCI International 1999 Proceedings 2 Volume Set
HCI International 2001 Proceedings 3 Volume Set
HCI International 2003 Proceedings 4 Volume Set
HCI International 2005 Proceedings 11 Volume CD Rom Set ISBN# 0-8058-5807-5
ch00_FM_8129_Lehto_LEA 7/2/07 9:36 AM Page iii
INTRODUCTION
TO HUMAN FACTORS
AND ERGONOMICS
FOR ENGINEERS
Mark R. Lehto
James R. Buck
ch00_FM_8129_Lehto_LEA 7/2/07 9:36 AM Page iv
Cover design by Tomai Maridou.
Lawrence Erlbaum Associates Lawrence Erlbaum Associates
Taylor & Francis Group Taylor & Francis Group
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ch00_FM_8129_Lehto_LEA 7/2/07 9:36 AM Page v
CONTENTS
Series Foreword xvii
Preface xix
Acknowledgments xxiii
CHAPTER 1 A Guided Tour
of Ergonomic Design 1
About this Chapter 2
Introduction 2
What Is Ergonomic Design? 4
Human-Centered Design 10
Military Equipment Design 14
Ergonomic Criteria 16
Models of Human Performance 17
Helson’s Hypotheses 18
Other Models 19
A Model of Software Design 24
Macroergonomics 25
Carrots and Sticks 29
Trends in Industry That Impact Ergonomic Design 30
Organizations and Additional Information on Ergonomic Design 34
Ergonomic Methods 34
Field Studies 35
Experimental Simulations 36
Laboratory Experiments 37
Computer Simulation 37
Differences in Ergonomic Methods 37
Final Remarks 38
Discussion Questions and Exercises 39
CHAPTER 2 The Human System 41
About this Chapter 42
Introduction 42
The Skeletal Subsystem 43
The Extremities 43
Joint-Related Disorders 46
The Spine 48
The Muscles 50
Muscle Contractions and Capabilities 50
The Role of Oxygen in Muscle Actions 52
Muscle Injuries and Disorders 53
Effects of Gender and Muscular Strength 53
Exercise as a Means of CTD Prevention 54
Anthropometry 54
Predicting the Stature of People 54
Estimating Body Dimensions 56
Predicting the Segment Mass of the Human Body 56
v
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vi Contents
Other Anthropometric Relationships 58
Body Movement 60
The Muscular-Skeletal System as Levers 60
The Sensory Subsystems 64
The Visual Sensory Subsystem 64
Human Perception of Sound 73
Position and Motion Sensing 77
Other Senses 80
Support Subsystems 81
Respiratory Operations and Mechanics 81
The Circulatory Subsystem 82
Metabolism 84
Indirect Calorimetry 87
Final Remarks 88
Discussion Questions and Exercises 89
CHAPTER 3 Design to Fit Tasks, Processes,
and People 93
About the Chapter 94
Introduction 94
Ergonomic Design Principles 95
Traditional Principles in Ergonomic Design 97
Visual Graphs of Operations 99
Operations Process Charts 100
Flow Process Charts 101
Flow Diagrams 103
Multiple Activity Charts 104
Precedence Diagrams and Matrices 105
Link Diagrams 106
Task Time-Line Analysis Graphs 108
Fault Trees 109
Failure Modes and Effects Tables 112
Cause-and-Effect Diagrams 112
Decision Flow Diagrams 114
Analysis of Tasks and Jobs 116
Describing the Task 117
Determining Task Requirements 120
Function Allocation 124
Final Remarks 126
Discussion Questions and Exercises 126
CHAPTER 4 Assessment and Design
of the Physical Environment 129
About the Chapter 130
Introduction 130
Cleanliness, Clutter, and Disorder 131
General Housekeeping and Maintenance 131
5S Programs 132
Air Quality and Ventilation 135
Temperature and Humidity 136
Thermal Regulation 136
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Contents vii
Heat Transfer 137
Control Strategies for Hot or Cold Environments 142
Assessing Thermal Conditions and Comfort 145
Effects of Thermal Conditions on Performance 154
Lighting and Illumination 154
The Luminous Environment and Its Measurement 156
Lighting Methods 160
Some Basic Principles and Lighting Requirements 163
Noise 172
Health Effects of Noise 173
Annoyance and Other Effects of Noise 175
Noise Control Strategies 176
Hearing Protection 177
Final Remarks 179
Discussion Questions and Exercises 179
CHAPTER 5 Design of Work Areas,
Tools, and Equipment 183
About the Chapter 184
Introduction 184
Applied Anthropometry 185
Drafting Templates 188
Computer Modeling Methods 189
Design of Work Areas and Stations 192
Traffic Areas 192
Workplace Dimensions and Layout Principles 195
Design of Seating 199
Office Design 205
Computer Workstations 205
Design of Tools and Equipment 214
Hands and Handedness: Some Initial Design Principles 214
Other Desired Properties of Grip Design 218
Other Features of Hand Tool Design 226
Techniques for Determining Hand Tool Adequacy 227
Power Tools 228
Power Transmission Hazards 230
Point of Operation Hazards 231
Protective Equipment for the Operator 234
Safety Shoes 234
Helmets 236
Protective Gloves 238
Eye Protection and Spectacles 239
Hearing Protection 240
Accommodating Handicapped People 240
Final Remarks 244
Discussion Questions and Exercises 244
CHAPTER 6 Methods Improvement and Motion
Analysis of Physical Tasks 247
About the Chapter 248
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viii Contents
Introduction 248
Methods Improvement 250
Principles of Motion Economy 251
Work-Physiology Related Principles 253
Motion and Micromotion Study 258
Biodynamics of Hand Motions 261
Speed-Accuracy Tradeoffs 262
Fitts’ Law 262
Eye-Hand Coordination 266
Some Principles of Manual Assembly 268
Manual Materials Handling 270
Principles of Lifting 274
Computer Tools for Analyzing Lifting Tasks 276
Ergonomic Support Belts 277
Grips and Grasps in Materials Handling 278
Handling Liquids and Powders 278
Carrying Methods 280
Equipment to Assist in Manual Materials Handling 281
Powered and Gravity Conveyors 283
Forklift Trucks 284
Wheelchairs 285
Final Remarks 285
Discussion Questions and Exercises 287
CHAPTER 7 Measurement of Human
Performance 289
About the Chapter 290
Introduction 290
Some Probabilistic Assumptions 292
Time Study 294
Performance Leveling 302
Determining Allowances 306
Machine Interference Allowances 309
Maintaining Standards 309
Indirect Performance Measurement 310
Criteria Other Than Time 311
Final Remarks 312
Discussion Questions and Exercises 312
CHAPTER 8 Predicting Human Performance 317
About the Chapter 318
Introduction 318
Synthetic Data Systems 319
Why Use a Synthetic Data System? 319
Motion-Time-Measurement (MTM) 320
Work-Factor System 329
Mento-Factor System 332
Standard Data Systems 335
Formula Development 336
Finding the Relationship among Predictive Variables
and Normal Performance 338
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Contents ix
Statistical Computer Packages for Regression 339
Cognitive Modeling 341
GOMS: Cognitive Work Measurement of a Skill-Based Task 349
NGOMSL 352
Final Remarks 356
Discussion Questions and Exercises 357
CHAPTER 9 Measurement of Learning
and Forgetting 361
About this Chapter 362
Introduction 362
Some Applications of Learning Curves 363
Modeling Human Learning 363
Why Use a Model of Learning? 364
Performance Criteria and Experience Units 364
Some Learning Curve Models 365
Powerform Learning Curve 366
Discrete Exponential Learning Curve 370
Fitting Learning Curves 373
The Powerform Model 373
The Discrete Exponential Model 374
Comparing Alternatives for Learnability 375
The Correct Learning Curve Model 376
Forgetting Curves 376
Final Comments 377
Discussion Questions and Exercises 378
CHAPTER 10 Sampling Methods in
Industrial Ergonomics 379
About this Chapter 380
Introduction 380
Activity Sampling 381
Sampling Procedures 382
Sampling Theory and Sample Size 384
Developing the Observation Schedule 387
Recording and Analyzing the Data 390
Checking for Stationarity 390
Using Work Sampling to Estimate Performance Standards 391
Using Work Sampling in Problem Solving 393
Sampling Strategies 394
Stratified Sampling 395
Sequential Bayesian Work Sampling 399
The Beta Distribution and Its Parameters 400
Bayesian Confidence Intervals 400
Finding Tabled Bayesian Confidence Intervals 401
Bayes’ Theorem and the Bayesian Concept 402
Managing a Bayesian Work Sampling Study 403
Poisson Activity Sampling 408
Final Comments 409
Discussion Questions and Exercises 409
