Safety cases introduction

The regulatory environment is changing in Victoria with introduction from March 2000 of the Major Hazard Facilities Regulations, based on the Seveso II Directives. These are expected to flow on to the other states considered in this chapter. The key requirement of these regulations is the preparation of a Safety Case, which must demonstrate, among other requirements, that the risk from the new plant has been reduced to as low as is reasonably practicable - ALARP . The plants will incorporate a number of design features intended to reduce the risk from the facilities and demonstrate compliance with this criterion. 

The stories we tell should have a resolution. In the case of major events such as Piper Alpha or Deepwater Horizon, the resolution could be new ways of managing safety (Safety Cases) or the introduction of new regulations (SEMS). Even less dramatic stories should always provide guidance to better behaviors or improved management systems. 

Whereas it is sensible to produce a (Project) Safety Case whenever a substantial change to an existing safety-related system (including the introduction of a new system) is to be undertaken, if that is all that we do - ie we do no also establish the absolute safety of the on-going service - then there is a risk that such changes are... 

The challenge from a governance perspective is to ensure that the operational safety case has identified the correct safety indicators and that these are being monitored sufficiently. Such identification is unlikely to be straightforward at the point of introduction of the equipment (or in this case infrastructure). The governance controls must therefore be sufficiently flexible to support the transition into operation and react as necessary to the indicator data. 

Identification of operational indicators Lack of explicit consideration of the issues within an operational safety case, as compared to a developmental safety case A non-adaptive governance system that is unable to support the transition from novel introduction to mature practice... 

We have limited our discussion in this paper to safety cases, but the concepts apply immediately to any property of interest. Thus, for example the notions of assured security cases or assured reliability cases are appropriate, and each would benefit from the explicit introduction of a confidence argument in the same way that a safety argument does. Naturally, the content of an assured security case would differ from the content of an assured safety case, but the overall structures and approaches would be identical. 

The scientific method, as currently understood, might not be familiar to engineers involved in system safety. A short introduction is therefore given here. Note that this addresses the process of science, not technical methods or scientific theories. This is followed by some comments on safety case fundamentals. The next section considers how a safety case can be seen from the viewpoint of scientific... 

Bell R(2010) Introduction and revision of lEC 61508. SIAS 2010, Tampere, Finland Bishop P, Bloomfield R (1998) A methodology for safety case development. In Redmill F, Anderson T (eds) Industrial perspectives of safety-critical systems. Springer Docker TWO (1979) Some aspects of computer simulation modelling. In Computer performance evaluation - a professional development seminar. New Zealand Computer Society, Hamilton... 

Prior to the introduction of the final SEMS rule there has been some speculation that the MMS/BOEMRE would require that safety cases be prepared for deepwater platforms. Many companies develop risk-based analyses of these platforms anyway because their loss would be so costly. Therefore, a safety-case requirement for those platforms may not be as demanding as it may sound. 

Finally, it must be stressed that a safety case is not a one-time event. A series of safety cases for each facility will be developed one each for design, operations and decommissioning as a minimum, in the case of production platforms. Moreover, none of these safety cases are static documents they need to be updated whenever there is a significant change to the design or operation of an offshore facility, say from a major expansion or the introduction of a new, hazardous chemical. 

The Introduction to the Safety Case summarizes issues such as the physical scope of work, the methods used to analyze risk, the project phases that are covered, and other major factors, such as the regulations that have to be addressed. 

Recent disasters in Australia in different industries have prompted different regulatory responses. In the state of Victoria, a gas plant accident which disrupted supplies to the state for two weeks (Hopkins, 2000) has led to the introduction of a safety case regime, while in the state of Queensland, a coal mine explosion which killed eleven men (Hopkins, 1999) led to a requirement that mines develop principle hazard management plans. This paper looks at the characteristics of the two different styles of regulation, explores reasons for these different responses, and draws some tentative policy conclusions. 

The process model is used to set a context for the safety case argument and to focus specific justification for each of the main areas of concern, as indicated by the GSN. For the relevant phase of the project, testing of the new trains in traffic hours, the only elements of tte overall process for train movements represented by the process model Figure 7-5, which are changed from the existing Victoria Line, are those associated with the introduction of the new train and the signalling system. The changes comprise ... 

Among the conclusions to a discussion of the potential for the introduction of a Safety Case approach to mining risk management, Rasche (2001) states ... 

However, even if there is little justification for the introduction of formalised Safety Cases based on quantified probabilistic risk assessment, the idea of using (qualitative) risk assessment to provide safety assurance for the introduction of new equipment, systems and operating practices has considerable potential merit. In order to distinguish such an approach from the formalised Safety Case approach, a simplified qualitative risk assessment approach to new equipment etc. could be usefully described as a Case for Safety approach. 

Part I of an operational safety case is an introduction and management summary. It will ... 

Table 6.1 Representative Safety Case Sizes Part Title 1 Executive Summary and Introduction Pages 40-50...

This book briefly reviews ammonia synthesis, its importance in the chemical process industry, and safety precautions. This case study is integrated into several chapters in the text. See the Introduction for further details. 

Significant modifications were made to the following topics dispersion modeling, source modeling, flammability characterization, explosion venting, fundamentals of electrostatics, and case histories. This new edition also includes selected materials from the latest AICHE Center for Chemical Process Safety (CCPS) books and is now an excellent introduction to the CCPS library. 

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