Total risk exposure codes

The ten severity codes (Table 11-3) represent single event losses from less than 100 to over 10 billion, with each severity code increasing by an order of magnitude. This scale provides a more meaningful assessment of the hazards associated with systems capable of producing multiple deaths and hundreds of millions or even billions of dollars in total losses (such as transportation system accidents). 

Ten exposure codes (Table 11-4) represent estimates of the total number of accidents for the system.The low end of the scale (exposure code of 1) rep- 

The total risk exposure code is then determined by adding the severity code and the exposure code (Fig. 11-6). 

The TREC has a real relationship to the estimated dollar losses associated with a system over its lifetime. 

Use of the TREC allows the system safety working group to provide the project manager with the following types of information  

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If RACs are, in fact, going to serve as the drivers in the system and the basis for risk acceptance and resource allocation decisions, the numbers generated must have a positive correlation to the risk involved and to the resources required to control the hazard. A universal RAC matrix would provide a means of comparing relative risks associated with multiple projects, evaluating the allocation of funds, and determining the cost-effectiveness of various controls. Ideally, this universal risk assessment code matrix could provide an evaluation of risks in absolute as well as relative terms. Chapter 12 contains a proposed universal RAC matrix (Total Risk Exposure Codes). The use of a meaningful, quantified, expanded universal RAC matrix may represent a practical approach to probabilistic risk assessment. 

Review the Total Risk Exposure Code matrix and risk acceptance criteria in Chapter 11. Adopt the risk assessment and acceptance criteria and methodology (as presented or as modified by the planning group) or develop and adopt alternatives. 

Figure 11-6 Total risk exposure code (TREC) matrix.

Define and discuss total risk exposure codes. 

Therefore, extreme value projection may be useful in calculation probabilities to be used for risk assessment codes or total risk exposure codes based on actuarial data. Extreme value projection can also be useful in communicating hazard information to management and may aid in drawing management attention to a problem before a serious accident occurs. 

After numerical point values are given to each job/task for severity, probability, and exposure, the point values are added to produce a total risk assessment code (RAC). A total score can be as low as 3 or as high as 10. Thus, each task is given... 

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