Risk Assessment. Marvin Rausand
documents and other information sources used in the risk assessment should be listed, together with proper references.
3.3.1.5 Acronyms and Glossary
Special terms or concepts that are used in the study should be listed and defined and/or explained.
3.3.1.6 Study Team
The name, position, competence, and role of each member of the study team should be listed.
3.3.1.7 Introduction
The introduction should describe the background for the study, the objectives, and the assumptions, together with a clear and concise tabulation of all known limitations and constraints associated with the risk assessment. Incidents and accidents that have taken place in similar systems should be listed.
The time interval during which the risk assessment was performed should also be recorded.
3.3.1.8 Description of the Study Object
The study object is described briefly together with its main functions. References to more detailed descriptions should be given. Conditions and limitations for operation of the study object should also be mentioned, for example, owners, responsibilities, location, staffing level, and important stakeholders (e.g. customers, passengers).
The description should contain sufficient information to verify that the study object is consistent with the assumptions made in the risk assessment.
3.3.1.9 Analysis Approach
This part of the report should give an overview of the analytical methods that have been used, for example, FMECA and HAZOP (see Chapter 10). In general, arguments for the choice of method should also be given.
3.3.1.10 Risk Acceptance Criteria
Acceptance criteria are important for evaluating the risk and should, therefore, be listed in the report. If risk matrices are used, the frequency and severity classification should be defined.
3.3.1.11 Hazards and Hazardous Events
Hazards, threats, and hazardous events that have been identified should be listed in this part: for example, in the format of a table. In some cases, it may be relevant to give a more detailed description of the most important hazardous events.
3.3.1.12 Models
The models, methods, and tools that are used in the risk assessment should be described, together with possible limitations of these in relation to the assessment.
3.3.1.13 Data and Data Sources
It is important to list and describe the information that is used such that the risk assessment can be verified by a third party. The data used should, as far as possible, be documented in a data dossier (see Chapter 9). A review of previous accidents and near‐accidents in similar applications should be part of this chapter.
3.3.1.14 Frequency and Consequence Analysis
This chapter presents the frequency and the consequences of each hazardous event. These should be combined to present the risk picture. Depending on the analytical approach selected, the results may often be presented in tables.
3.3.1.15 Sensitivity and Uncertainty Assessments
The results from the risk assessment are subject to a wide range of uncertainties, depending on the input data, the models and methods used, and the knowledge of the study team (see Chapter 19). To give a realistic picture of the risk, the uncertainty of the input data should be discussed. In some cases, it may be relevant to run sensitivity analyses to show how the uncertainty in the input data influences the end result.
The report should address any analytical limitations that are expected to affect the main results of the risk assessment.
3.3.1.16 Identification and Assessment of Risk Reduction Measures
Based on the results from the risk assessment, it should be considered whether any risk reduction measures should be implemented. Possible measures that have been identified in the assessment should be described in this chapter.
3.3.1.17 Discussions of Results
It is important to discuss the results from the risk assessment and to check that they are compatible with the objectives of the study. Have we addressed the questions we were asked to answer? We must check whether the analyses are sufficient, or if it is necessary to do more detailed analyses. All this should be mentioned in the report.
3.3.1.18 Conclusions and Recommendations
Finally, all the conclusions that may be drawn from the risk assessment should be listed, along with possible proposals for further work. It is important to check that all recommended changes to the study object or its operation have properly been listed as action items.
3.3.1.19 Appendices
In most cases, several documents, drawings, detailed worksheets, and so on, have been used in the risk assessment. These are often too voluminous to be included in the main report and should therefore either be included as appendices to the report or be mentioned in the document references.
The amount of information in the appendices should be limited. If in doubt about the benefit of including material as an appendix, it should probably be omitted.
3.3.1.20 General Comments
A slightly different report structure is described in Chapter 5 of U.S. DOE (2004), and some valuable advice on writing an efficient report based on a risk assessment is given by IAEA (1994).
The report must always be written such that it can be reviewed, verified, and updated. After completion, the risk assessment report should be reviewed and factually validated by the company. It may also be beneficial to have a third‐party review before the results are used.
The risk assessment will sometimes cover deliberate actions and the system's vulnerability relative to these threats. It is then important to realize that notes, worksheets, and other documentation from the risk assessment will be sensitive data that should be kept confidential. This documentation must therefore be graded and kept confidential. Nothing makes a company more vulnerable than a vulnerability study that has gone astray.
3.4 Risk Assessment in Safety Legislation
A number of EU directives and regulations make it mandatory to carry out various types of risk assessment of a wide range of potentially hazardous systems and activities. This is also the case in other parts of the world. Some main laws are introduced briefly below to illustrate the wide span of application:
The Seveso directive. The EU Directive on the control of major accident hazards involving dangerous substances (82/501/EEC) is often referred to as the Seveso directive because it was issued in response to the Seveso accident in 1977. The Seveso directive was amended in 1986 and 1988 to take into account the lessons learned from the Bhopal accident and the Sandoz fire. A more significant revision of the directive was issued in 1996 as a consequence of the Piper Alpha accident, and is called the Seveso II directive (EU 1996).