Process Equipment Design

Transcription

1 CHAPTER 4 Process Equipment Design 4.1 INTRODUCTION People operate and maintain processes by interacting with process equipment. Process equipment includes displays, alarms, controls, computers, manual equipment, and personal protective equipment. Human factors issues for process equipment relate to how people interact with and use equipment. The characteristics of the equipment may increase the likelihood of human failures when it is used by people. These human factors issues are addressed by studying the match between the attributes of people and those of the equipment. Optimizing this match helps improve process safety. Key attributes of people include: Physical capabilities such as strength, vision, hearing, and size. Intellectual capabilities such as understanding of the process, diagnosing problems, attention span, and speed of thought. Skills such as use of tools and reading level; knowledge such as that of process hazards and abnormal operations. Behavior such as responsibility and motivation. Education and training. Communication skills. Key attributes of equipment include location, accessibility, size, shape, color, orientation, and so on. Process equipment designs should consider capabilities of people such as physical (e.g. strength), psychological (e.g. speed of processing information) and social (e.g. communication abilities). The diversity of equipment used in processes, their characteristics, and those of people, result in a wide variety of human factors design issues. These are generally well-known. The challenge is to apply the existing knowledge and account for synergistic effects resulting from people and equipment functioning as parts of complex systems. Fundamental human factors design principles can be defined for equipment and include: Suitability meets requirements for the task. Simplicity avoids unnecessary complexity. Human Factors Methods for Improving Performance in the Process Industries American Institute of Chemical Engineers

2 32 PROCESS EQUIPMENT DESIGN Identifiability easily found and recognized by personnel. Accessibility easily reached. Detectibility easily seen or heard. Availability there when needed. Logic and consistency organization, arrangement, operation, etc. makes sense. Flexibility adjustable to the user. Conformity with user expectations operation matches user training and previous experience. Adherence to these principles should be balanced and tailored to specific situations. Human interaction with process equipment is affected by the physical, social, and organizational environments in which it occurs. Consequently, issues identified in other sections of this book should also be addressed when considering equipment design. Furthermore, human-equipment interaction should be addressed from an overall systems perspective that considers the entirety of the process and all the people who are part of it. Human factors for alarms and visual display units are covered in detail in Chapter 5 on Process Control Systems and Chapter 9 on the Human/Computer Interface. Figure 4-1 shows a good application of colors to improve the readability of a pressure gauge. In Transition In Range Pressure In Range Vacuum Not in Range Figure 4-1: The application of color to improve the readability of a pressure gauge.

3 4.3 REFERENCES 33 An operator used a piece of pipe as a helper or persuader to open a stiff drain valve on a tank. The valve was infrequently used and not the correct type for this service. He applied too much pressure and broke off the valve handle with the valve in the open position. The entire contents of the tank drained into the dike surrounding the tank. 4.2 TOOLS Human factors design principles for equipment are well established. There are established texts on the subject (Sanders and McCormick, 1993; Anon., 1986). Various standards also exist. The International Organization for Standardization (ISO) has published a standard on ergonomic requirements for the design of displays and control actuators (ISO , 1999). Part 1, Human Interactions with Displays and Control Actuators specifies general principles. Control actuators are defined as the part of the control system that is actuated by the operator. Some guidance is provided on methods that can be used to achieve the principles described. Part 2, Displays, provides guidance on the selection, design and location of displays to avoid potential ergonomic hazards associated with their use (ISO , 1999). It specifies ergonomics requirements and covers visual, audible and tactile displays. Part 3, Control Actuators and Part 4, Location and Arrangement of Displays and Control Actuators are under development. The UK Health and Safety Executive has provided guidelines for data presentation in displays and the selection of controls (HSE, 2004). The UK Ministry of Defence has an extensive set of standards for the human factors design of equipment (Def Stan 00-25, 1987; 1997a; 1997b; 1992a; 1992b; 1997c; 1996a; 1989a; 1991; 1992c; 1988; 1989b, 1996b) and there are also US military standards relating to human factors design (MIL-STD-1472D, 1989; MIL-HDBK-759A, 1981). Detailed guidance is also available from the nuclear industry (NUREG-0700, 2002; ANSI/IEEE 845, 1988; ANSI/IEEE 1023, 1988; NUREG CR-4227, 1985). Information in these standards can be adapted to the process industries. However, the guidance is highly detailed in many cases and may act as an obstacle to process industry companies beginning to adopt human factors design principles and guidelines for equipment. A simple checklist has been suggested for equipment design in the process industries (Attwood, et al., 2004). The human factors design principles listed in section 20.1 provides a simple guide when designing or modifying equipment. 4.3 REFERENCES Anon. (1983; 1986), Ergonomic Design for People at Work, Volumes 1 and 2, Eastman Kodak Company (New York: Van Nostrand Reinhold). ANSI/IEEE 845 (1988), Guide to Evaluation of Man Machine Performance in Nuclear Power Generating Stations, Control Rooms, and Other Peripheries (Washington, DC: American National Standards Institute).

4 34 PROCESS EQUIPMENT DESIGN ANSI/IEEE 1023 (1988), Guide for the Application of Human Factors Engineering to Systems, Equipment and Facilities of Nuclear Power Generating Stations (Washington, DC: American National Standards Institute). Attwood, D. A., Deeb, J. M. and Danz-Reece, M. E. (2004), Ergonomic Solutions for the Process Industries (Amsterdam: Elsevier). Def Stan 00-25, Human Factors for Designers of Equipment (Glasgow: UK Ministry of Defence). 1987: Part 1: Introduction 1988: Part 11: Design for Maintainability 1989a: Part 8: Auditory Information 1989b: Part 12: Systems 1991: Part 9: Voice Communication 1992a: Part 4: Workplace Design 1992b: Part 5: Stresses and Hazards 1992c: Part 10: Controls 1996a: Part 7: Visual Displays 1996b: Part 13: Human Computer Interaction 1997a: Part 2: Body Size 1997b: Part 3: Body Strength and Stamina 1997c: Part 6: Vision and Lighting HSE (2004) (London: UK Health and Safety Executive). ISO (1999a), Ergonomic requirements for the design of displays and control actuators Part 1: Human interactions with displays and control actuators (Geneva, Switzerland: International Organization for Standardization). ISO (1999b), Ergonomic requirements for the design of displays and control actuators Part 2: Displays (Geneva, Switzerland: International Organization for Standardization). MIL-HDBK-759A (1981), Military Handbook, Human Factors, Engineering Designs for Army Material (Washington, DC: U.S. Department of Defense). MIL-STD-1472D (1989), Human Engineering Design Criteria for Military Systems, Equipment and Facilities (Washington, DC: U.S. Department of Defense). NUREG/CR-4227 (1985), Human Engineering Guidelines for the Evaluation and Assessment of Visual Display Units (Washington, DC: U.S. Nuclear Regulatory Commission). NUREG-0700 (2002), Human-System Interface Design Review Guidelines, Rev. 2 (Washington, DC: U.S. Nuclear Regulatory Commission). Sanders, M. S. and McCormick, E. J. (1993), Human Factors in Engineering and Design, 7th ed. (New York: McGraw-Hill). 4.4 ADDITIONAL REFERENCES BS EN (1997), Safety of machinery. Ergonomics requirements for the design of displays and control actuators. Part 1. General principles for human interactions with displays and control actuators (London: British Standards Institution).

5 4.4 ADDITIONAL REFERENCES 35 BS EN (1997), Safety of machinery. Ergonomics requirements for the design of displays and control actuators. Part 2. Displays (London: British Standards Institution). BS EN (1997), Basic and safety principles for man-machine interface, marking and identification. Coding principles for indication devices and actuators (London: British Standards Institution). BS 3693(1992), Recommendations for the design of scales and indexes on analogue indicating instruments (London: British Standards Institution). BSR/HFES 100 (2002), Human Factors Engineering of Computer Workstations, Draft Standard for Trial Use (Santa Monica, CA: Human Factors and Ergonomics Society). HSE (1992) L26, Display Screen Equipment Work Guidance on Regulations (London: UK Health and Safety Executive). HSE (1998), The Management of Alarm Systems, CRR 166/1998 (London, UK Health and Safety Executive). IEC Ed. 1.0 b (1995), Safety of machinery Indication, marking and actuation Part 1: Requirements for visual, auditory and tactile signals (Geneva: International Electrotechnical Commission). IEC Ed. 1.0 b (1995), Safety of machinery Indication, marking and actuation Part 2: Requirements for marking (Geneva: International Electrotechnical Commission). IEC Ed. 1.0 b (1999), Safety of machinery Indication, marking and actuation Part 3: Requirements for the location and operation of actuators (Geneva: International Electrotechnical Commission). ISO (1999), Safety of machinery Safety-related parts of control systems Part 1: General principles for design (Geneva, Switzerland: International Organization for Standardization). ISO (2003), Safety of machinery Safety-related parts of control systems Part 2: Validation (Geneva, Switzerland: International Organization for Standardization). ISO/TR (2000), Safety of machinery Safety-related parts of control systems Part 100: Guidelines for the use and application of ISO (Geneva, Switzerland: International Organization for Standardization). ISO (2003) Safety of machinery Basic concepts, general principles for design Part 1: Basic terminology, methodology (Geneva, Switzerland: International Organization for Standardization). ISO (2003), Safety of machinery Basic concepts, general principles for design Part 2: Technical principles (Geneva, Switzerland: International Organization for Standardization). ISO (1996), Safety of machinery Emergency stop Principles for design (Geneva, Switzerland: International Organization for Standardization). ISO 7731 (2003), Ergonomics Danger signals for public and work areas Auditory danger signals (Geneva: International Organization for Standardization).