Human factor

Some key human factor issues remain overlooked or ignored by healthcare leaders. Continuous improvement processes always shift the focus from individuals to teams, processes, or systems. The concept known as migrating decision making permits a person with greatest expertise (regardless of rank) to make an important decision. Finally, managing complexity of patient care can and often does exceed the capabilities of individuals. 

The guiding premises for making systems inherently safer against human error are  

CCPS (1994a) and Lorenzo (1990) discuss human error in detail. They 

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. 

The discussion in the following sections is not comprehensive it is intended to provide examples. The inherently safer design strategy (see Section 2.6) used in most of the examples is Simf lify. 

The objective of the review of human factors is to determine the status of the various human factors that may affect the safe operation of the nuclear power plant. 

The design shall be operator friendly and shall be aimed at limiting the effects of human errors. Attention shall be paid to plant layout and procedures (administrative, operational and emergency), including maintenance and inspection, in order to facilitate the interface between the operating personnel and the plant. 

The working areas and working environment of the site personnel shall be designed according to ergonomic principles. 

Systematic consideration of human factors and the human-machine interface shall be included in the design process at an early stage and shall continue throughout the entire process, to ensure an appropriate and clear distinction of functions between operating personnel and the automatic systems provided. 

The human-machine interface shall be designed to provide the operators with comprehensive but easily manageable information, compatible with the necessary decision and action times. Similar provisions shall be made for the supplementary control room. 

Verification and validation of aspects of human factors shall be included at appropriate stages to confirm that the design adequately accommodates all necessary operator actions. 

Consider character as moral and/or ethical structures of individuals or groups. Belief refers to a mental act and habit of placing trust in someone or something. Human values focus on what people believe and things of relative worth or importance. Culture refers to socially accepted behaviors, beliefs, and traditions of a group. 

A person s attitude or their state of mind relates to their feelings about something. Behaviors relate to the open manifestation of a person s actions in any given situation. 

This can be viewed as the combination of people, processes (the procedures they follow, both management and technical), and the technology that they operate to perform their job. If the balance between the three is not well thought out, it can create serious safety problems. This section describes how the company views human factors within the SMS and addresses how it is considered during designing, operating, and maintaining equipment and systems. Chapter 8 discusses human factors techniques in more detail. 

Meaningful analysis of the people part of systems tend to be a problem for some parts of the system safety community for two reasons. 

humans have many more failure modes and are far less predictable than hardware. Accurately determining human reliability is extremely difficult. Considerably less reliable data are available on human performance than on hardware. 

Second, few engineering programs prepare graduates for evaluating human behavior and human performance. Chapter 8 provides an overview of basic human factors engineering. 

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Quantitative determined visual recognition for usual inspections, indicate that for indications with lengths over about 1.5 mm tbe probability of recognition is about 100 %. This is also applied to the penetrant inspection. This does not include the so called "human factor" which means that it cannot be guaranted that the inspector detects all indications for instance not always observing the inspection surface with full concentration. 

Naturally, such a high probability of detection of theoretically 100% never can be realized in practice. The inspector will not recognize all good visible indications at any time because he cannot always be fiilly concentrated on his task, which is called "human factor". This human factor appears in any visual inspection and may be reduced only by a second redundant inspection or extreme signals as a light flash or an acustic signal. 

The new ultrasonic test system ISONIC minimizes the influence of human factors and allows even higher reliability compared with most of the automatic scanners. 

The new test system was developed in order to largely eliminate the human factors for manual ultrasonic testing as described above. The system consists of three components ... 

R. A. Murgatroyd, G.M. Worrall, und S. Crutzen Lessons leamt from the RISC 111 study of the influence of human factors on inspection reliability. 6 European Conference on Nondestructive Te.sting, Nice. 1994, Vol. 2, p 989-993... 

BE-1732 Human factors in aircraft dispatch and maintenance safety Dr. N. Me Donald Univ. Dublin Trinity College... 

Several nontechnical factors can significantly affect the results of a nondestmctive inspection. Many of these are classified as human factors (1,2,17). Operator experience affects the probabiUty of detection of most flaws. Typically, an inexperienced operator has more false rejects, known as Type II errors, than an experienced operator. A poor operator has few false rejects but is more likely to miss a defect in the inspection, known as a Type I error. Operator fatigue, boredom, or an unfavorable environment such as lighting, cold, or rain may further affect performance. Thus it usually is a good investment for the inspection company to assure that the operator environment is most amenable to inspection, that the equipment is suitable for the task, and that the operator is alert and well rested. 

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. 

Technical data. Health, Safety and Human Factors Laboratory, Eastman Kodak Co., Rochester, N.Y., 1980. 

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. 

Factor V. High in sialic acid content. Factor V is a large asymmetric single-chain glycoprotein that becomes an active participant in the coagulation cascade when it is converted to its active form by a-thrombin. Approximately 25% of human Factor V is found in the whole blood associated with platelets. Factor V is an essential cofactor along with Factor Xa plus phosphohpid plus Ca " in the conversion of prothrombin to thrombin. 

Human Factors A diseipline eoneerned with designing maehines, operations, and work environments so that they mateh human eapabilities, limitations, and needs. Ineludes any teehnieal work (engineering, proeedure writing, worker training, worker seleetion, ete.) related to the human faetor in oper-ator-maehine systems. 

Test runs also allow the primary steps of operating procedures to be validated and checked for logic or human factors aspects. 

However, power systems that cater to almost fixed loads at a time and whose variations occur only at specific times of the day may not reejuire it fast response. In such cases, it is possible to provide manual switching methods which will give enough time between two switchings. Manual switching, how ever, has certain shortcomings, due to the human factor such as its accuracy and diligence, as noted above. The recommended practice is therefore to select fast reactive controls as noted below. 

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. 

Woodson, W. E., Tillman, B. and Tillman, P. 1992 Human Factors Design Handbook. NY McGraw-Hill. 

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 equipment design must be compatible with the human factor requirements, as presented in Chapter 6. 

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. 

Likewise, the equipment can be made inherently safer for human factors by... 

As new equipment becomes available and insights about ergonomics and human factors become available, we should review new and existing facilities to optimize the person-machine interface. 

New facilities should be reviewed for ergonomics and human factors issues during design, construction, and startup. Existing facilities should be reviewed periodically for opportunities to improve human factors in an inherently safer way. 

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). 

For inherently safer interactions of designs and procedures, include an operator trained in human factors on the design team. 

Human factors should be considered in the location of items to be maintained and the required frequency of maintenance ... 

From a broader perspective, the Abnormal Situation Management Consortium is working to apply human factors theory and expert system technology to improve personnel and equipment performance during abnormal conditions. In addition to reduced risk, economic improvements in equipment reliability and capacity are expected (Rothenberg and Nimmo, 1996). 

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