Safety system goal

Step 2 Do Begin the implementation of the safety system goals and objectives. 

Another way of interpreting absolute risk estimates is through the use of benchmarks or goals. Consider a company that operates 50 chemical process facilities. It is determined (through other, purely qualitative means) that Plant A has exhibited acceptable safety performance over the years. A QRA is performed on Plant A, and the absolute estimates are established as calibration points, or benchmarks, for the rest of the firm s facilities. Over the years, QRAs are performed on other facilities to aid in making decisions about safety maintenance and improvement. As these studies are completed, the results are carefully scrutinized against the benchmark facility. The frequency/consequence estimates are not the only results compared—the lists of major risk contributors, the statistical risk importance of safety systems, and other types of QRA results are also compared. As more and more facility results are accumulated, resources are allocated to any plant areas that are out of line with respect to the benchmark facility. 

At this point, a task analysis is performed. A "task" is defined as an activity oi performance (hat the operator sees as a unit either because of its performance character]stic.s or becau.se that activity is required as whole to achieve some part of the system goal. Only the tasks that are relevant lo the system safety are considered. A task analysis involves decomposition of each task into individual units of behavior. Unusually, this analy.sis tabulates information about each specific human aciiun. The format of such a table is not rigid - any style that allows easy retrieval ot the information can be used. The format reflects the level of detail and the type of task analysis performed. The analysis yields... 

The reliability and availability performance requirements of safety systems and especially fire protection systems should be considered in the design. Fire protection systems are not used on a regular basis, but must work when required. It is also important that the design of the fire protection system facilitate a testing and maintenance program for achieving these goals. 

An engineering evaluation should then be made of the worst case consequences with the goal that the plant will be safe even if the worst case occurs. When the process designers know what the worst case conditions are, they should try to avoid worst case conditions, be sure adequate redundancy of safety systems exists, and identify and implement lines of defense. These lines of defense could be preventive measures, corrective measures or sometimes as a last resort, containment or possibly abandonment of the process if the hazard is unacceptable. It is important to note that the worst case should be something that is realistic, not something that is conceivable but extremely unlikely. 

Process safety improvement efforts will include performance goals that define the desired future state for the various elements of the process safety system. Examples may include 100-percent reporting of process safety incidents and near misses, 100-percent on-time completion of process safety training, and timely resolution for all hazards analysis recommendations. 

The ultimate goal of the process safety system is to prevent process safety incidents. The Center for Chemical Process Safety s Process Safety Leading and Lagging Metrics Report (CCPS, 2007b) defines a consensus from several chemical and allied processing industries for definitions of process safety incidents and process safety near misses. If an organization adopts these definitions, a... 

As described in Chapter 4, in an ideal process safety system, the organization s goals, objectives, and metrics should be reflected across the organization and, as appropriate, in the performance expectations and contracts of individuals with responsibilities under the system. A key factor in ensuring that systems perform as intended is to hold responsible personnel accountable for desired results—objective metrics are one way to measure and document... 

The human factors literature is rich in task analysis techniques for situations and jobs requiring rule-based behavior (e.g., Kirwan and Ainsworth 1992). Some of these techniques can also be used for the analysis of cognitive tasks where weU-practiced work methods must be adapted to task variations and new circumstances. This can be achieved provided that task analysis goes beyond the recommended work methods and explores task variations that can cause failures of human performance. Hierarchical task analysis (Shepherd 1989), for instance, can be used to describe how operators set goals and plan their activities in terms of work methods, antecedent conditions, and expected feedback. When the analysis is expanded to cover not only normal situations but also task variations or changes in circumstances, it would be possible to record possible ways in which humans may fail and how they could recover from errors. Table 2 shows an analysis of a process control task where operators start up an oil refinery furnace. This is a safety-critical task because many safety systems are on manual mode, radio communications between control room and on-site personnel are intensive, side effects are not visible (e.g., accumulation of fuel in the fire box), and errors can lead to furnace explosions. 

To achieve the goals set at the end of the last chapter, a new theoretical underpinning is needed for system safety. Systems theory provides that foundation. This chapter introduces some basic concepts in systems theory, how this theory is reflected in system engineering, and how all of this relates to system safety. 

Efforts to develop nuclear power reactors have been focused on the enhancement of safety and reliability by using active safety systems with redundancy and diversity while improving economy through scale factor. Although the goals have been fairly achieved, traditional power reactors can be used only under the prerequisites and are thus usable for a limited area of application. 

Monitor company goals and safety system compliance in areas of responsibility and report deviations to management. 

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