Coarse analysis

Figure 21.2 illustrates how the starting point, the directions and the scope of each method fit into the accident-analysis framework of Chapter 6. Two of the methods. Fault tree analysis and Comparison analysis are deductive in that they start with the unwanted event. They proceed by analysing the underlying incidents and deviations (Fault tree analysis) or contributing factors (Comparison analysis). Several of the methods are mainly inductive in that they start with a deviation and proceed by studying the effects of this deviation. This applies to HAZOP, Failure mode and effect analysis. Event tree analysis and CRIOP, although they also have a component of causal analysis. Coarse analysis and Job-safety analysis start with the hazard and use a combination of inductive and deductive analyses. 

The first three methods analyse the risk of occupational accidents. They have a joint theoretical basis in the framework for accident analysis described in Chapter 6. The methods serve different purposes. Often, Coarse and Job-safety analysis are used in combination by starting with the Coarse analysis. A Job-safety analysis will follow when severe hazards have been identified and there is a need to go into details on how they may result in harm. We will... 

The aim of a Coarse analysis is to identify and evaluate the hazards of the different areas of a plant. The Energy model is its theoretical basis. Those hazards representing the potential of severe losses are focused upon. A Coarse analysis typically follows a stepwise procedure. 

This chapter gives a detailed description of each step of the Coarse analysis. We will apply the same basic steps in all the four risk-analysis methods presented here. We will not repeat the description of each basic step in such detail for the other risk-analysis methods. 

Example In a Coarse analysis of an aluminium plant, the plant was broken down into the following analysis objects carbon section for manufacturing of cathodes electrolysis foundry and transportation. The latter is geographically spread over the whole plant. 

The group or team leader has to be well acquainted with the Coarse analysis method and have management capabilities. The team leader is responsible for ... 

Preparation consists of the collection and review of documents about the analysis object and familiarisation with it. A typical list of documents for a Coarse analysis includes ... 

In the Coarse analysis, we especially want to focus on hazards that may result in serious consequences. It is also recommended to focus on hazards that may result in many (but less severe) accidents. Consult the accident statistics for the actual plant or similar plants for accident concentrations. Results are documented on a record sheet according to Table 22.3. 

Table 22.3 Record sheet for documentation of the results of a Coarse analysis. An example from a foundry at an aluminium plant is shown...

All findings from the analysis are documented in the Coarse analysis record sheet according to Table 22.3. The following outline is proposed for the analysis report ... 

A Coarse analysis results in information on hazards and potential accidents similar to that obtained though accident investigations. In many cases it may be practical to store the results in a computer for easy retrieval and summarisation. This approach offers several advantages ... 

Example An aluminium company conducted a Coarse analysis of its primary aluminium plants. An analysis team was established for each department that participated in the analysis. The teams were lead by SHE experts from the corporate staff. In addition the teams included the department supervisor and operations and maintenance personnel. 

The aim of a detailed job-safety analysis (JSA) is to identify and evaluate the hazards to which employees are exposed when performing work activities. It is similar to a Coarse analysis, but differs as to the level of detail by which the activities are broken down. 

In this step we find the largest differences between the Coarse analysis and the detailed JSA. The JSA team reviews and describes the activities, one after the other in a sequence. It is thus necessary that personnel with operational experience participate in the team. Remember to include all activities, also those outside normal practices. What disturbances can occur and what will then be done The checklist in Table 22.1 is used as an extra control to ensure that no activities have been forgotten. 

The subsequent steps do not in principle differ from those of the Coarse analysis, see Section 22.2. In JSA, there are requirements to comprehensiveness and no hazards are too insignificant to be documented. All hazards will sooner or later result in injuries or near accidents, if they are not remedied. 

All activities are reviewed by application of Coarse analysis. The results are used as a basis for decisions on which activities to focus upon in detailed JSA. 

In the Coarse risk assessment, the machinery mannfacturer or the party responsible for the assembly of machinery identifies the main hazards and necessary risk-reducing measures. The purpose is also to identify the need for detailed risk assessments. This activity has to be performed at an early design stage before layout freeze and placement of major purchase orders of subdeliveries. A team similar to the Coarse analysis team is responsible for the analysis, see Chapter 22. The procedure shown in Figure 24.2 is applied and the results are documented in a record sheet according to Table 24.1. 

The method that is selected for the detailed risk assessments may vary, depending on the types of safety problem involved. If, for example, the reliability of safety systems is a concern, fanlt tree analysis or failure mode and effect analysis may be the appropriate method. Here, a detailed risk assessment similar to the job-safety analysis of Chapter 23 is presented. It follows the general ontline of the coarse analysis of Figure 24.2 but is performed at a more detailed level. The aim is to study manual activities in the danger zones of the machinery in detail in order to take the necessary precautions. A team will be responsible for this analysis as well. Resnlts are documented in a record sheet according to Table 24.2. 

The project carries out coarse working environment evaluations including a Coarse analysis. These serve as input to concept selection. Norskoil s operations department participates in these evaluations. 

Figure 27.6 shows how the different analyses and evaluations of the risk of occupational accidents are co-ordinated with the design process (Kjellen, 1990 Kjellen, 1998). They are part of a total evaluation of all SHE aspects. Each activity has been defined and scheduled in Norskoil s and the contractor s SHE programmes for the Ymer project. During conceptual design, the experience checklist is established and the coarse analysis is carried out. 

Example A coarse-analysis team reviews the handling of heavy tools between the store and the drillfloor. They look especially into the layout of the store and the location of the monorail. They also review the line of sight from winch control panels into the danger zone for material handling. The analysis team decides about the exact position of the monorail and the location of winches. 

---