Human Factors Process

Society of Petroleum Engineers (SPE). Summit Paper. The Human Factor, Process Safety and Culture. Eds. Patrick Hudson and John L. Thorogood. November 2012. 

In July 2012, the Society of Petroleum Engineers (SPE 2012) organized a Summit on the topic of The Human Factor, Process Safety and Culture. The meeting lasted for 2 days and there were approximately 70 attendees, all of whom were experts in the area of risk management and/or human factors in the energy and process industries. The title page of the Summit document states, This paper is not intended to be a recommendation or guideline, but the consensus view of Summit attendees. ... 

Because of the extensive and important roles of operators and other plant personnel in the operation and use of I C systems important to safety (and of the plant as a whole), human factor processes should be integrated into the overall design process. 

Visual Inspection. Visual inspection should always be regarded as the first defense against failure (1). Without scientific proof, it is estimated that 80% of defects are found by visual inspection. A pilot walking around an aircraft, or a mechanic observing a machine in operation often finds defects very quickly. The cost of this inspection is minimal. Human factor considerations are particularly important for the visual inspection process. Although the visual inspection is perhaps the most inexpensive and finds the most defects, the 20% of the defects remaining after the visual inspection must also be found thus the more costly and technically elaborate NDE methods are needed. 

Comfort. In the past, the evaluation of fabric or garment comfort has been a subjective process influenced by such variables as temperature, insulating efficiency, moisture absorption, drying speed, softness, bulk, fabric constmction, and air permeability. Human factors must also be considered. 

B. J. M. Ale, The Implementation of an External Safety Policy in the Netherlands, International Conference on Elazard Identification and Risk Analysis, Human factors and Human Reliability in Process Safety, January 15-17, 1992, Orlando, PL, 173-183, American Institute of Chemical Engineers, New York, NY, 1992. 

Human factors are an extremely important part of inherently safer concepts. Processes should be designed to avoid error traps. Chapter 6 of this book presents a discussion of human factors as related to inherently safer design. 

The tools in CCPS (1994a) can be used in each stage of the chemical process life cycle to help evaluate the tradeoffs involving human factors between various options. In many cases, low cost options in design can make the operations inherently safer from a human factors perspective. 

From a human factors perspective, the chemistry of the process can be made inherently safer by selecting materials that can better tolerate human error in handling, mixing, and charging. If a concentrated reagent is used in a titration, precision in reading the burette is important. If a dilute reagent is used, less precision is needed. 

There may be well-run facilities in which the operators are doing their best to be careful with facilities or systems that could be redesigned to be inherently safer. These facilities will be inherently safer if designed for operability. Note that inherently safer human factors features can reduce risk of injury to employees (improved personnel safety) and can reduce risk to the process from the worker (improved process safety). 

As noted in Step 13 of the inherent safety review at the design development stage, the team reviews the process to develop a list of potential ergonomics/human factors issues. This list provides input to the design team so that these issues can be addressed as the design progresses. 

Mill, R. C. (Ed.), 1992, Human Factors in Process Operations, Institute of Chemical Engineers, Rugby, U.K. 

In the course of assessing your company s current PSM status, you and your team have almost certainly gained a clear sense of which facilities pose the greatest risk, whether by virtue of inherent process hazards, human factors, management systems, or a combination. As you set priorities for implementation you should closely review information gleaned from the assessment tasks. In addition, you should try to validate or flesh out your impressions through some more quantitative analysis that can help to identify priority facilities. 

This book has been written to show how the science of human factors can be applied at the plant level to significantly improve human performance and reduce human error, thus improving process safety. 

The application of the science of human factors to eliminating error in all aspects of process design, management, operation, and maintenance is the focus of this work. Human error has been a major cause of almost all of the catastrophic accidents that have occurred in the chemical process industries (CPI). If one adopts the broad view of human error as being the result of a mismatch between human capabilities and process demands, then clearly management s role is critical in the following areas ... 

The book begins with a discussion of the theories of error causation and then goes on to describe the various ways in which data can be collected, analyzed, and used to reduce the potential for error. Case studies are used to teach the methodology of error reduction in specific industry operations. Finally, the book concludes with a plan for a plant error reduction program and a discussion of how human factors principles impact on the process safety management system. 

Chapter 8, A Systematic Approach to the Management of Human Error, explains how the manager and safety professional can use human factors principles in the management of process safety. This chapter also provides a practical plan for a plant human error reduction program that will improve productivity and quality as well. 

The major benefits that arise from the application of human factors principles to process operations are improved safety and reduced down time. In addition, the elimination of error has substantial potential benefits for both quality and productivity. There is now a considerable interest in applying quality management approaches in the CPI. Many of the major quality experts em-... 

Despite the lack of interest in human factors issues in the CPI in the past, the situation is now changing. In 1985, Trevor Kletz published his landmark book on human error in the CPI An Engineer s View of Human Error (revised in 1991). Several other books by the same author e.g., Kletz (1994b) have also addressed the issue of human factors in case studies. Two other publications have also been concerned specifically with human factors in the process industry Lorenzo (1990) was commissioned by the Chemical Manufacturers Association in the USA, and Mill (1992), published by the U.K. Institution of Chemical Engineers. In 1992, CCPS and other organizations sponsored a conference on Human Factors and Human Reliability in Process Safety (CCPS, 1992c). This was further evidence of the growing interest in the topic within the CPI. 

The first component of the systems approach to error reduction is the optimization of human performance by designing the system to support human strengths and minimize the effects of human limitations. The hiunan factors engineering and ergonomics (HFE/E) approach described in Section 2.7 of Chapter 2 indicates some of the techniques available. Design data from the human factors literature for areas such as equipment, procedures, and the human-machine interface are available to support the designer in the optimization process. In addition the analytical techniques described in Chapter 4 (e.g., task analysis) can be used in the development of the design. 

Human Factors Engineering/Ergonomics approach (control of error by design, audit, and feedback of operational experience) Occupational/process safety Manual/control operations Routine operation Task analysis Job design Workplace design Interface design Physical environment evaluation Workload analysis Infrequent... 

Although the main thrust of the HSE work is directed to providing inputs to the CPQRA process, the audit procedure generates valuable qualitative information regarding both the quality of the overall plant management and also the specific human factors dimensions which affect risk. 

In subsequent sections the application of PIFs to various aspects of error reduction will be described. One of the most important of these applications is the use of comprehensive lists of PIFs as a means of auditing an existing plant to identify problem areas that will give rise to increased error potential. This is one aspect of the proactive approach to error reduction that forms a major theme of this book. This application of PIFs can be used by process workers as part of a participative error reduction program. This is an important feature of the human factors assessment methodology (HFAM) approach discussed in Section 2.7. 

Process workers often complain that valves are inaccessible. Emergency valves should always be readily accessible but other valves, if they are operated, say, once a year or less often, can be out of reach. It is reasonable to expect workers to get a ladder or scramble into a pipe trench at this frequency. Designers should remember that if a valve is just within reach of an average person then half of the population cannot reach it. Equipment should be placed such that at least 95% of the population can reach it. Guidance on specific measurements to achieve this objective is available in a number of standard human factors textbooks (see Bibliography). 

The term control panel refers to the instrumentation console in a central control room through which process information is communicated to the process worker and via which the worker changes the state of the process. This category includes display elements such as chart recorders, bar indicators, dials, and modem VDU-based systems together with control elements such as buttons, switches, track balls and mice. The control panel is the human-machine interface (see Chapter 2) that has traditionally received the most attention from human factors specialists. 

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