Safety performance causal factors

This chapter pleads for an awareness of the need for a balanced approach that gives a proper emphasis within the practice of safety to causal factors deriving from design management, operations management, and task performance. 

Analyze Barriers and Potential Human Performance Difficulties During this phase of the analysis process, the barriers that have been breached by the accident are identified. TTiese barriers could include existing safety systems, guards, containment, etc. This analysis is called barrier analysis. The causal factors from SORTM are also applied in more detail. 

System dynamics steps to solve the problem (Wu J.Z. et al. 1985) is (1) to identify the problem how the coal mine safety input influence factors of coal mine production, which in turn affect coal mine safety performance (2) to determine the system boundary safety production system in coal mine (3) to determine causal graph and define the variable draw causal graph of coal mine safety production system and define the model variable (4) to establish equations, models and analyze the simulation model. 

Safety level of coal mine production factors is affected by safety input which includes staff, funding, technology equipment, etc.. The more investment in safety, the higher level of safety factor and the safety performance make better. When safety performance is close to the expected, the safety investment is reduction. The causality diagram is shown in Fig. 2. 

Emphasize that a balance of considerations is needed for causal factors deriving from less-than-adequate policies, standards, or procedures that impact on the design management, operations management, and task performance aspects of safety. 

As shown in Figure 1, the SMS contains several sub systems. First, a system of reporting and collection of experience data from the vessel itself is required. This is followed by a system of data processing, i.e. smnmarization and analysis in order to reveal causal factors and perform trend analysis, which forms the basis for the development of safety measures. One critical system requirement is the reliabihty and accuracy of input data, i.e. near miss and accidents reports. As long as the input is rehable, the overall system presupposes the possibility of developing efficient measures, in order to control operational... 

Human error continues to be implicated as a causal factor in accidents in high-risk industries worldwide. As Wieathall and Reason (1992) have so eloquently stated, the history of accidents is also the history of the human contribution to accidents. While human error is frequently seen as indicative of poor performance or aberrant behavior, this view is both counter-productive and typically untme from the perspective of aviation safety. It is now well established that error is a natural part of human performance, and frequently unavoidable in day-to-day work activities. To this end, understanding the predictable aspects of human error in high-risk work environments, and examining the relationship between error occurrenee and error management, form important new frontiers for aviation safety. 

The analysis portion of the accident investigation is not a single, distinct part of the investigation. Instead, it is the central part of the process that includes collecting facts and determining causal factors. Well-chosen and carefully performed analysis is important because it provides results that can be used by a company to improve its safety and health performance. 

Rodrigues, F., Coutinho, A. Cardoso, C. (in press). Correlation of causal factors that influence construction safety performance a model. Work—A Journal of Prevention, Assessment arui Rehabilitation. 

Selected defence/protection measures should be stated in the form of safety requirements on performance, function, procedure, environment, competence and other reduction methods. The safety requirements must then be apportioned to those projects and suppliers that are responsible for delivery of the equipment, people and procedures that embody the causal factors identified in the analysis. 

In system safety, parts and components are of prime interest because it is often their unique failure modes, within unique system architectures, that provide the IM for certain hazards within a system design. Failure mode and effects analysis (FMEA) and FTA typically deal with the system at the part or component level in order to determine the risk presented by a particular hazard. When an FTA is performed to determine the causal factors for a particular hazard or UE, the FTA is generally conducted to the part level. Failure rates can be obtained for parts, which can be used in the FTA to generate a quantitative result. 

Since a function performs a desired task, the erroneous performance of a function, or the failure to perform a function when needed, may result in serious safety consequences. Erroneous function and failure to function can result from many different or combined causal factors, such as hardware failures, hardware tolerance errors, system timing errors, software errors, human errors, sneak circuits, and environmental factors. The criticality of the function typically determines the safety vulnerability involved. Functions can be real or abstract entities in a system, and they should be recognized in an overall system functional hierarchy. 

FHA is a powerful, efficient, and comprehensive system safety analysis technique for the discovery of hazards. It is especially powerful for the safety assessment of software. Since software does not have discrete failure modes as hardware does, the best way to identify software-related hazards is by evaluating the effect of potential software functions failing. Software is built upon performing functions therefore, FHA is a very natural and vital tool. After a functional hazard is identified, further analysis of that hazard may be required to determine if the causal factors of the functional failure are possible. Since the FHA focuses on functions, it might overlook other types of hazards, such as those dealing with hazardous energy sources, sneak circuit paths, and hazardous material (HAZMAT). For this reason, the FHA should not be the sole HA performed, but should be done in support of other types of HA, such as PHA and SSHA. 

Mishaps involve a set of causal factors that lead up to the final mishap event, and these factors are the actuated hazard conditions. Mishap causal factors can be identified prior to an actual mishap through the application of HA. Mishaps are an inevitable consequence of antecedent causes and, given the same causal factors, the same mishap is repeatable, with the frequency based on the component probabilities. Mishaps can be predicted via hazard identification, and they can be prevented or controlled via hazard elimination or hazard control methods. This safety concept demonstrates that we do have control over the potential mishaps in the systems we develop and operate. We are not destined to face an unknown suite of undesired mishaps, unless we allow it to be so (by not performing adequate system safety). In the safety sense, mishaps are preplanned events in that they are actually created through poor design and/or inadequate design foresight. 

The SSHA is performed when detailed design information is available as it provides a methodology for analyzing in greater depth the causal factors for hazards previously identified by earlier analyses such as the PHA. The SSHA helps derive detailed SSRs for incorporating design safety methods into the system design. 

The real value and need for TLMs is based on the need for system hazard clarity and focus. The use of TLMs helps to resolve some safety programmatic issues, such as (a) hazard abundance, (b) hazard confusion, (c) subsystem confusion, and (d) total mishap risk. As HAs are performed on a system design, many hazards are identified, sometimes in the thousands. With a large number of hazards, it often becomes difficult to maintain hazard visibility. Sometimes hazards are inadvertently repeated sometimes hazards are stated as causal factors rather than hazards. Hazard risk can be assessed against TLMs to determine if a thread exists that creates increased risk for that TLM category. 

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