Analysis root cause

Root cause analysis (RCA) may simply be described as a systematic investigation approach that makes use of information collected during an assessment of an accident, for determining the underlying factors for deficiencies that caused the accident [5,6]. It was developed by the U.S. Department of 

Energy for investigating incidents [7]. The following 10 general steps are involved in performing RCA [7-9]  

Root cause analysis is used when there are multiple problems with a number of causes of an accident. A root cause analysis is a sequence of events that shows, step by step, the events that took place in order for the accident to occur. Root cause analysis puts all the necessary and sufficient events and causal factors for an accident in a logical, chronological sequence. It analyzes the accident and evaluates evidence during an investigation. It is also used to help prevent similar accidents in the future and to validate the accuracy of preaccidental system analysis. It is used to help identify an accident s causal factors, which, once identified, can be fixed to eliminate future accidents of the same or of similar nature. 

On the downside, root cause analysis is a time-consuming process and requires the investigator to be familiar with the process for it to be effective. As you will see later in this chapter, you may need to revisit an accident scene multiple times and look at areas that are not directly related to the accident to have a complete event and causal factor chain. Analysis requires a broad perspective of the accident to identify any hidden problems that would have caused the accident. 

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  

Direct causes (unplanned release of energy or hazardous material) 

Indirect causes (unsafe acts and unsafe conditions) 

A root cause analysis is not a search for the obvious but an in-depth look at the basic or underlying canses of occnpational accidents or incidents. The following should be considered when performing analyses  

Chart events in chronological order, developing an events and causal factors chart as initial facts become available. 

Stress aspects of the accident that may be causal factors. 

Establish accurate, complete, and substantive information that can be used to support the analysis and determine the causal factors of the accident. Stress aspects of the accident that may be the foundation for judgments of needs and fntnre preventive measures. 

Resolve matters of speculation and disputed facts through investigative 

A root cause analysis is not a search for the obvious but an in-depth look at the basic or underlying causes of occupational accidents or incidents. The basic reason for investigating and reporting the causes of occurrences is to enable the identification of corrective actions adequate to prevent recurrence and thereby protect the health and safety of the public, the workers, and the environment. Every root cause investigation and reporting process should include five phases. While there may be some overlap between phases, every effort should be made to keep them separate and distinct. The phases of a root cause analysis are  

The objective of investigating and reporting the cause of occurrences is to enable the identification of corrective actions adequate to prevent recurrence and thereby protect the health and safety of the public, the workers, and the environment. Programs can then be improved and managed more efficiently and safely. 

This line of reasoning will explain why the occurrence was not prevented and what corrective actions will be most effective. This reasoning should be kept in mind during the entire root cause process. Effective corrective-action programs include the following  

A description of each of these phases is provided to clarify the purpose of each phase of the root cause analysis. 

20 CONDUCTING TEAM ROOT CAUSE ANALYSIS SESSIONS 

Lack of proper instructions Job, task, or safety rules not enforced Inadequate PPE, incorrect tools, and improper equipment Poor planning, improper job procedures, and rushing the worker 

Use of shortcuts and/or working too fast Incorrect use of or failure to use protective equipment Horseplay or disregard of established safety rules Physical or mental impairment on the job Using improper body motion or technique 

Ineffective machine guarding Defective materials and tools Improper or poor equipment design Using wrong tool or using tool improperly Poor preventive maintenance procedures 

Poor lighting or ventilation Crowded or poorly planned work areas Poor storage, piling, and housekeeping practices Lack of exit and egress routes Poor environmental conditions such as slippery floors 

If only the eye injury cases had been evaluated, a significant reason for not using the goggles (representing significant risk) would not have been addressed. In other words, the 75% of the employees who did not wear their goggles because they had left them in their lockers would not have been addressed. 

One such example is the approach that the U.S. National Institute of Standards and Technology (NIST, 2009) used to investigate an accidental plutonium spill at a Boulder, Colorado, facility. In summary, the steps the team took were as follows  

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Check whether a documented system is in place, which covers the reporting, investigation, root cause analysis and corrective actions taken. 

FMEA is particularly suited for root cause analysis and is quite useful for environmental qualification and aging analysis. It is extensively used in the aerospace and nuclear ]iowei indiistrii-s but seldom used in PSAs, Possibly one reason for this is that FMEA, like parts count. ,s not chrectlv suita lundant systems such as those that occur in nuclear power plants Table i 4... 

Auditor has to advise supplier to conduct root cause analysis on all NCs. 

You will be required to perform a root cause analysis on each detected nonconformity. 

In addition to incident reporting systems, root cause analysis techniques can be used to evaluate the causes of serious incidents where resources are usually available for in-depth investigations. A practical example of root cause investigation methods is provided in Chapter 7. 

Chapter 6 discusses the ways in which feedback for operational experience can be enhanced by improved data collection and root cause analysis tech-... 

Root cause analysis systems, intended to provide in-depth evaluations of major incidents... 

This section discusses the company culture that is necessary to support effective data collection and root cause analysis. 

The types of data required for incident reporting and root cause analysis systems are specified. Data Collection practices in the CPI are described, and a detailed specification of the types of information needed for causal analyses is provided. 

However, in the case of a root cause analysis system, a much more comprehensive evaluation of the structure of the accident is required. This is necessary to unravel the often complex chain of events and contributing causes that led to the accident occurring. A number of techniques are available to describe complex accidents. Some of these, such as STEP (Sequential Timed Event Plotting) involve the use of charting methods to track the ways in which process and human events combine to give rise to accidents. CCPS (1992d) describes many of these techniques. A case study involving a hydrocarbon leak is used to illustrate the STEP technique in Chapter 7 of this book. The STEP method and related techniques will be described in Section 6.8.3. 

In the case of root cause analysis systems, more comprehensive evaluations of PIFs will normally be carried out as part of a full-scale human factors audit. This could make use of the types of comprehensive PIF evaluation methods described in Chapter 2 (see Section 2.7.7 and Figure 2.12). 

For a major incident investigation using a comprehensive root cause analysis system, teams will be formed to acquire information relevant to determine the structure and analyze the causes in depth. In addition to evaluations of the immediate causes, imderlying causes are likely to be evaluated by investigations in areas such as safety and quality management. Both paper- and computer-based systems will be used to acquire and record information for subsequent detailed analyses. 

In the following sections, a number of methodologies for accident analysis will be presented. These focus primarily on the sequence and structure of an accident and the external causal factors involved. These methods provide valuable information for the interpretation process and the development of remedial measures. Because most of these techniques include a procedure for delineating the structure of an incident, and are therefore likely to be time consuming, they will usually be applied in the root cause analysis of incidents with severe consequences. 

Identify human performance difficulties for Root Cause Analysis... 

Workforce Support for Data Collection and Incident Analysis Systems Few of the incident investigation and data collection systems reviewed provide any guidelines with regard to how these systems are to be introduced into an organization. Section 6.10 addresses this issue primarily from the perspective of incident reporting systems. However, gaining the support and ownership of the workforce is equally important for root cause analysis systems. Unless the culture and climate in a plant is such that personnel can be frank about the errors that may have contributed to an incident, and the factors which influenced these errors, then it is unlikely that the investigation will be very effective. 

In the second case study, variation tree analysis and the events and causal factors chart/root cause analysis method are applied to an incident in a resin plant. This case study illustrates the application of retrospective analysis methods to identify the imderlying causes of an incident and to prescribe remedial actions. This approach is one of the recommended strategies in the overall error management framework described in Chapter 8. 

The case study has documented the investigation and root cause analysis process applied to the hydrocarbon explosion that initiated the Piper Alpha incident. The case study serves to illustrate the use of the STEP technique, which provides a clear graphical representation of the agents and events involved in the incident process. The case study also demonstrates the identification of the critical events in the sequence which significantly influenced the outcome of the incident. Finally the root causes of these critical events were determined. This allows the analyst to evaluate why they occurred and indicated areas to be addressed in developing effechve error reduchon strategies. 

To gather information about the factors which contributed to the above incident, interviews were held with the workers and their management. Relevant documentation such as standard operating procedures and documentation relating to the incident was also collected. A task analysis (see Case Study 3) of the job of the top floor person was carried out in order to examine the operations involved and the factors which could affect job performance. Two techniques were used for the analysis of this incident, namely variation tree analysis and root cause analysis. 

This involves the development of data collection and root cause analysis systems as described in Chapter 6. 

Armstrong, M. E., Cecil, W. L., Taylor, K. (1988). "Root Cause Analysis Handbook." Report No. DPSTOM-81, E. I. DuPont De Nemours Co., Savannah River Laboratory, Aiken, SC 29808. 

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