Hazards root cause analysis

Once the causal factors have been identified, the factors are analyzed using a root cause analysis tool, such as 5-AVhys or predefined trees. See Chapter 9 for a more detailed discussion of Barrier Analysis (sometimes called hazard-barrier-target analysis or HBTA) and Change Analysis (also referred to as Change Evaluation/Analysis or CE/A). In essence, these tools act as a filter to limit the number of factors, which are subjected to further analysis to determine root causes. 

One problem to watch for during root cause analysis is that of fixation. Fixation can be a serious problem when conducting a root cause analysis because people tend to view potential hazards in light of their own experiences and opinions. During discussions people tend to take up a particular point of view, and then obstinately defend it, even when they are proven to be wrong. They develop pride of ownership in their opinions. In other words, people tend to pick on one or two events, or perceived causes of events, and will not change their mind from that point forward. In the literal sense of the word, they are prejudiced, because they prejudge events and the causes of events. 

Chapter 3 presents introductory aspects of safety and human factors. Chapter 4 is devoted to methods considered useful to perform patient safety analysis. These methods include failure modes and effect analysis (FMEA), fault tree analysis (FTA), root cause analysis (RCA), hazard and operability analysis (HAZOP), six sigma methodology, preliminary hazard analysis (PFfA), interface safety analysis (ISA), and job safety analysis (JSA). Patient safety basics are presented in Chapter 5. This chapter covers such topics as patient safety goals, causes of patient injuries, patient safety culture, factors contributing to pahent safety culture, safe practices for better health care, and patient safety indicators and their selection. 

Like its popular predecessors, the book supplies a complete overview of hazard control, safety management, compliance, standards, and accreditation in the healthcare industry. This edition includes new information on leadership, performance improvement, risk management, organizational culture, behavioral safety, root cause analysis, and recent OSHA and Joint Commission Emergency Management requirements and regulatory changes. 

The principal role of the U.S. Chemical Safety Board is investigating accidents to identify the conditions and circumstances that led to the events. It also investigates hazardous conditions that could lead to accidents. The agency uses root cause analysis and other methods to identify causes to prevent events. It makes recommendations to government agencies, companies, trade associations, labor unions, and other groups. It publishes reports and offers DVDs about cases it investigates. 

Evaluate hazard information using a practical approach Investigate accidents and near-miss events to discover causes Conduct root cause analysis to uncover contributing causes Determine woiker perceptions about safety in the workplace Deal with perceptions (it cannot be avoided)... 

The reporting and analysis of all types of incidents is a responsibility of employees and management. The Health and Safety Department can assist in managing safety in several ways. These professionals have special training and expertise in the area of root cause analysis. Their services are very valuable in identifying potential hazards and contributing causes, which you may not recognize. 

One of the simplest root cause analysis techniques is to determine the causes of accidents/ind-dents at different levels. During any hazard analysis we are always trying to determine the root cause of any accident or incident. Experts who study acddents often do a breakdown or analysis of the causes. They analyze them at three different levels ... 

After the hazard analysis is finished, a question based on the hazard root cause failure mechanism is created and added to the hazard checkhst. The Independent Verification and Validation Group (IV V) generates a respective test case. These test cases are collected in a Hazard Test Procedure Book. 

The set of mechanisms that reduce or eliminate exposures to hazard in the working interface. Different organizations classify these mechanisms in different ways, but they usually include hazard recognition and mitigation, incident root cause analysis, training, regulations, procedures, policies, and safety improvement programs. 

The guidance for tliis element covers responsibilities and authorities, determination of the significance of a quality (ESH/PSM) related problem, root cause investigation, cause-and-effect analysis, preventive actions and additional controls, and change documentation. For ESH/PSM, this element might be interpreted as covering both potential hazards as well as actual problems. 

Checklists may also be used to supplement other tools for example, checklists on human factors may be used in conjunction with logic trees. Similarly, checklists may be used in combination with structured brainstorming tools such as What If/Checklist and Hazard and Operability (HAZOP) Analysis.(P It is also a good practice to apply a tool like the 5-Whys to the root causes identified from the checklist to verify whether they are truly root causes. 

Identifying the potential hazards (PHA, process hazard analysis, or HAZOP, hazard and operability analysis) during operation must be done from a wide-angle approach dangerous situations can occur due to many root-cause situations other than those specified by, for instance, ASME or PED. Based on the results of the risk assessment, the pressure equipment can be correctly designed and the most effective safety system selected. 

The Type A investigation of a sodium potassium (NaK) accident that occurred at the Y-12 plant on December 8, 1999, identified a lack of understanding of the hazard from NaK and its reactive byproducts as one of the root causes of the accident. The investigation found that personnel involved in planning the task, the safety documentation for the facility, the procedure for the task, and the procedures supporting hazard identification and analysis did not address the complete NaK hazard. The investigation also determined that detailed hazard identification data supported by accident analysis and appropriate control information was readily available. 

Vinnem, J.E. (2010) Analysis of root causes of major hazard precursors in the Norwegian offshore petroleum industry , Reliability Engineering and System Safety, 95 (11) 1142-1153. 

The accident analysis report determines and documents the root causes of accidents associated with the end product and includes new hazards, hazards inadequately controlled or analyzed, and new baseline information identified by the accident analysis in the system safety effort. 

Recommended preventive actions should make it very difficult, if not impossible, for the incident to recur. The investigative report should list all the ways to foolproof the condition or activity. Considerations of cost or engineering should not enter in at this stage. The primary purpose of incident investigations is to prevent future occurrences. Beyond this immediate purpose, the information obtained through the investigation should be used to update and revise the inventory of hazards, and/or the program for hazard prevention and control. For example, the Job Safety Analysis should be revised and employees retrained to the extent that it fully refiects the recommendations made by an incident report. Implications from the root causes of the accident need to be analyzed for their impact on all other operations and procedures [6]. 

The analysis suggests fliat most control system failures may have their root cause in an inadequate specification. In some cases this was because insufficient hazard analysis of the equipment under control had been carried out in others it was because the impact on the specification of a critical failine mode of the control system had not been assessed. 

The main motto of the study is that it is possible for the operator and others concerned to understand the nature of each hazard. The analysis shall be done in depth so that root cause is well identified, and appropriate remedial or control measures could be prescribed. The success of the study will not be achievable if only hazard is identified. The study shall be deep enough to indicate When, Where, and Why a hazard is present. 

Initiating event In hazard analysis, an event could be the occurrence of a deviation which may lead to an accident. So, the initiating events are the causes for which there is the process deviation. The initiating events may be or may not be the most basic underlying root-causes, but are the results of the root causes. According to CCPS there are three types of initiating events or causes ... 

Fault tree analysis is also very effective in determining the root cause of accidents and near miss incidents. It helps evaluate equipment failure and predict potential hazards. Fault tree analysis is a useful safety audit tool that uses very simple statements of fact and is very objective and realistic. 

It is Strongly reconunended that an FMEA be used to investigate further how a particular failure (which leads to a hazard) can come about. The FMEA should not be used as the primary safety analysis tool. A more appropriate application is to hazard and operability (HAZOP) a particular part of the plant. Once the safety-critical operations have been identified, then FMEA can be used very selectively to focus on how particular failure modes might lead to process deviations and thus create a hazard. The primary reason for this is that FMEAs are a very laborious effort and easy to become bogged down. But their strength is going to the piece-part level, as necessary, to determine root causes, and this of course is paramount in understanding how to control a hazard. 

In broad terms, the process for producing a specification for a safe design involves hazard identification (HAZID), which asks what sort of accidents do we need to worry about , followed by detailed analysis to identify the magnitude of potential accidents. From a safety perspective, a most important step is the clear and robust definition of the safety functional requirements, i.e., the requirements for the control and protection systems on the completed plant. The history of accidents involving design failures shows a frequent root cause to be inaccurate or inadequate definition of the safety functional requirements (see Fig. 2.3). 

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