Offshore QRA and the ALARP principle

A discussion is presented of the use of QRA within a requirement, of the UK offshore safety case regime, to demonstrate that risks from offshore major accidents are ALARP. General considerations are given to uncertainties in failure and incident data, assumptions and consequence methodologies within the analysis element of offshore QRA. The validity of risk results arising from the analysis element is discussed in the context of such results being viewed on the basis of a classical interpretation of probability (the interpretation most often used for offshore QRA), and comments are made about the nature of results in relation to a distinction between objective knowledge and subjective ignorance. Consideration is given to a Bayesian interpretation of probability (rarely used for offshore QRA), and to the role that QRA may have when this interpretation is adopted against a background of some basic principles of engineering safety.     

On risk assessment in the petroleum activities on the Norwegian and UK continental shelves

This article discusses some key principles and tools of safety management, with focus on risk analyses, risk interpretation, risk acceptance criteria and risk communication, as well as emergency preparedness. The starting point for the discussion is the experience from the activity on the Norwegian and UK continental shelves, and the implementation of new safety regulations in particular.     

On the ALARP approach to risk management

There is an increasing trend by regulatory authorities for the introduction of the as low as reasonably practicable (ALARP) approach in dealing with risk management of proposed or existing complex hazardous systems. For these, decisions about acceptability or tolerability of risks and consequences can have very significant financial, economic and other consequences for the proponents. Conversely, there may be very significant social and socio-economic implications. ALARP as a guide to achieving a satisfactory outcome has a certain intuitive appeal for the practical management of industrial and other risks. However, as suggested herein, there are a number of areas of concern about the validity of this approach. These include representativeness, morality, philosophy, political reality and practicality. An important, and in some respects fundamental, difficulty is that the risk acceptance criteria are not fully open to public scrutiny and can appear to be settled by negotiation.     

On safety management in the petroleum activities on the Norwegian Continental Shelf

This paper discusses some key principles and tools of safety management. Emphasis is placed on the process of establishing cost-effective solutions which meet the risk acceptance criteria and emergency preparedness requirements. The starting point for the discussion is the new regulations issued by the Norwegian Petroleum Directorate on risk analysis and emergency preparedness in the petroleum activities on the Norwegian Continental Shelf.     

On the use of the hybrid causal logic method in offshore risk analysis

In the Norwegian offshore oil and gas industry risk analyses have been used to provide decision support for more than 20 years. The focus has traditionally been on the planning phase, but during the last years a need for better risk analysis methods for the operational phase has been identified. Such methods should take human and organizational factors into consideration in a more explicit way than the traditional risk analysis methods do. Recently, a framework, called hybrid causal logic (HCL), has been developed based on traditional risk analysis tools combined with Bayesian belief networks (BBNs), using the aviation industry as a case. This paper reviews this framework and discusses its applicability for the offshore industry, and the relationship to existing research projects, such as the barrier and operational risk analysis project (BORA). The paper also addresses specific features of the framework and suggests a new approach for the probability assignment process. This approach simplifies the assignment process considerably without loosing the flexibility that is needed to properly reflect the phenomena being studied.     

Major hazard risk indicators for monitoring of trends in the Norwegian offshore petroleum sector

The Petroleum Safety Authority Norway (PSA, formerly Norwegian Petroleum Directorate) took in 1999 the initiative to develop a method in order to assess trends and status for the risk levels in the Norwegian offshore petroleum industry. A method was developed, and a pilot study report was issued in April 2001, covering the period 1996–2000. Annual updates have been performed since then, and the latest report covers the period 1996–2004. The statistical approach is based on recording occurrence of near misses and relevant incidents, performance of barriers and results from risk assessments. Of similar importance is an evaluation of safety culture, motivation, communication and perceived risk. This is covered through the use of social science methods, such as questionnaire surveys and a number of interviews, audit and inspection reports as well as accident and incident investigations. There are also indicators for occupational accidents and occupational illness/-physical working environment factors.The focus is on the major hazard risk components for personnel staying on the offshore installations. An overview of the indicators used to illustrate these risk aspects is presented, followed by a discussion of the analytical approach used for these indicators. Results from the risk assessment for the Norwegian Continental Shelf in the period 1996–2004 are used throughout for illustration, and discussion of challenges.     

Perspectives on risk: review and discussion of the basis for establishing a unified and holistic approach

There exist many perspectives on risk, including safety engineering, social scientist perspectives, risk perception research and economic decision analysis. Traditionally, some of the different perspectives have been viewed to represent completely different frameworks, and the exchange of ideas and results has been difficult. Much of the existing discussions on risk perspectives have in our view lacked a sufficient level of precision on the fundamental ideas of risk assessments and management. For example, there is more than one line of thinking in risk analysis and assessment and mixing all approaches into one, gives a rather meaningless discussion. In this paper, we review some of the most common perspectives on risk. We show that it is possible to establish a common basis for the different perspectives, by looking at risk as the full spectrum of the dimensions (a) possible consequences and (b) associated uncertainties. Examples from the offshore oil and gas industry are included to illustrate ideas.     

ALARP—What does it really mean?

This paper examines the requirements that might reasonably be regarded as being implied by the ALARP principle. The principle stipulates that those responsible should reduce risks of death and injury for workers and members of the public to levels that are ‘As Low As Reasonably Practicable’. The main aim of the paper is to resolve the apparent conflict between the ALARP principle on the one hand and, on the other, conventional social cost-benefit analysis. In particular, cost-benefit analysis prescribes that a safety improvement should be undertaken only if the cost of doing so is less than or equal to the resultant benefits, whereas some regulatory agencies interpret ALARP as requiring that the improvement must be undertaken provided that costs are not in ‘gross disproportion’ to benefits, which would clearly include cases in which costs might substantially exceed benefits.     

Acceptance rules for concrete strength

Compliance criteria proposed in the literature are examined and analytical expressions for the owner's and the producer's risk implied by these criteria are given. For safety, as well as for economical reasons, the equality of the two risks is proposed and from this equality the constants of the compliance criteria are computed. It is shown that the common risk becomes lower if instead of the two acceptance rules proposed in the literature a single rule is applied and the constants of the single rule which minimizes the common risk are determined.     

A decision framework for risk management, with application to the offshore oil and gas industry

In this paper we present and discuss a decision framework for risk management. The framework comprises the basic elements: problem definition (challenges, goals and alternatives), stakeholders, concerns that affect the consequence analyses and the value judgments related to these consequences and analyses (frame conditions and constraints), identification of which consequence analyses to execute and the execution of these, managerial review and judgement, and the decision. The framework has novel aspects on the way of classifying the decision situations and characterising risks. The classification is based on the two dimensions, expected consequences, and uncertainties. Our starting point is the offshore oil and gas industry, but our framework and discussion is to a large extent general and could also be applied in other areas. An example is outlined to illustrate the use of the framework.     

On the consistency of risk acceptance criteria with normative theories for decision-making

In evaluation of safety in projects it is common to use risk acceptance criteria to support decision-making. In this paper, we discuss to what extent the risk acceptance criteria is in accordance with the normative theoretical framework of the expected utility theory and the rank-dependent utility theory. We show that the use of risk acceptance criteria may violate the independence axiom of the expected utility theory and the comonotonic independence axiom of the rank-dependent utility theory. Hence the use of risk acceptance criteria is not in general consistent with these theories. The level of inconsistency is highest for the expected utility theory.     

Reliability modeling of surface controlled subsurface safety valves

The article discusses the consequences of choosing a Weibull life distribution instead of an exponential distribution. The discussions are based on a specific data set for surface controlled subsurface safety valves (SCSSVs) used in offshore oil and gas production wells. The estimates of the mean time to failure and the mean fractional dead-time based on the stochastic censored data set, are shown to be non-robust with respect to variations of the Weibull parameters. The availability of the SCSSV as a safety barrier against blowouts is discussed in relation to risk acceptance criteria and the principle of ‘as low as reasonably practicable’. Replacement policies to balance the risk and operational cost are proposed and discussed.     

Quantitative risk analysis offshore—Human and organizational factors

Quantitative Risk Analyses (QRAs) are one of the main tools for risk management within the Norwegian and UK oil and gas industry. Much criticism has been given to the limitations related to the QRA-models and that the QRAs do not include human and organizational factors (HOF-factors). Norway and UK offshore legislation and guidelines require that the HOF-factors are included in the QRAs. A study of 15 QRAs shows that the factors are to some extent included, and there are large differences between the QRAs. The QRAs are categorized into four levels according to the findings. Level 1 QRAs do not describe or comment on the HOF-factors at all. Relevant research projects have been conducted to fulfill the requirements of Level 3 analyses. At this level, there is a systematic collection of data related to HOF. The methods are systematic and documented, and the QRAs are adjusted. None of the QRAs fulfill the Level 4 requirements. Level 4 QRAs include the model and describe the HOF-factors as well as explain how the results should be followed up in the overall risk management. Safety audits by regulatory authorities are probably necessary to point out the direction for QRA and speed up the development.     

A "worst case" methodology for obtaining a rough but rapid indication of the societal risk from a major accident hazard installation

This paper describes a methodology developed to provide a rough but rapid indication of the magnitude of the societal risks at and in the vicinity of a major accident hazard installation. It is intended to be used by the UK Health & Safety Executive (HSE) as a first screening tool when examining safety reports submitted under The Control of Major Accident Hazards (COMAH) Regulations 1999. These are the Regulations which implement in the UK the major aspects of Council Directive 96/82/EC, the "Seveso II" Directive. Within the methodology a new weighted risk integral parameter is defined, suitable for comparison with criteria, and its value calculated. The paper includes examples to illustrate the use of the methodology.     

人工智能时代的设计创新及其价值重塑

在探讨人工智能影响和意义的基础上,梳理当代设计的形式和思维,明确当代设计创新的本质和方式。从人工智能时代设计的呈现面貌、表达方式、思维结构及价值规范等方面来分析设计现状和趋势,指出人工智能在设计创作和接受层面带来的变革,以及在人工智能背景下,设计创新的必要性和伦理观。自包豪斯、乌尔姆确立高度系统设计原则以来,基于系统化原则的现代设计不断地突破和发展,极大地完善了社会功能结构。在人工智能的影响下,当代设计不断加强对社会全链条的支持力度,拓展了设计思维在社会各领域的可实现路径,促进了设计的概念延展、观念创新和产业转型,不仅为当代设计创新提供了新的契机,而且在重塑社会关系的过程中形成了新的价值观念。     

Justification in clinical radiological practice: a survey among staff of five London hospitals

This study represents a survey performed among staff who, according to the Ionising Radiation (Medical Exposures) Regulations of 2000 (IRMER), are responsible for justifying radiological examinations in the UK. The aim of the survey is to map the current situation regarding knowledge of risks from X-ray exposures and the criteria used for their justification. An anonymous electronic questionnaire was emailed to 219 radiologists and radiographers of five National Health Service hospitals. The questions were designed to investigate the way the sample group defines/assesses risk and benefit when justifying medical exposures, and to test their knowledge on radiation doses, risk communication, and on relevant national legislation. The majority of the respondents are aware of the relevant legislation/guidelines. Patient's medical condition, age and sex, and alternative techniques using less or no ionising radiation are the main criteria used for justification. However, when estimating the effective dose of various examinations in chest radiograph equivalents, the majority of the responses were incorrect. Although there is good knowledge of legislation around justification of medical exposures, there seems to be a lack of knowledge on radiation doses and risks among IRMER practitioners.     

Time effects in criteria for acceptable risk

A simple normative theory is proposed for the responsible management of risks to the public. A ‘lifesaving’ alternative, if it is truly to save lives, should return to the community more years of life expectancy in good health than the years of work consumed to pay for its cost. This common-sense time principle of risk management provides a criterion for acceptable risk that is applicable in connection with cost-utility analysis. The principle is a benchmark, providing a unified rationale for the assessment of risks in health care and technology. Integration of acceptable risk criteria with criteria for national performance can be achieved via applicable compound social indices such as the Life Quality Index or the Human Development Index.     

Stochastic modelling for the analysis of blowout risk in exploration drilling

This article discusses the theoretical basis and the general framework related to stochastic blowout modelling in an offshore risk management context. The general scope is put forward by the Norwegian Petroleum Directorate (NPD) and the operating companies' need for an adequate decision making tool that permits studies of the effects of implemented risk reducing measures based on local conditions. Previous work and today's practices regarding stochastic modelling for the analysis of blowout risk are reviewed and discussed. Moreover, a different and perhaps more thorough approach to blowout risk modelling in exploration drilling is suggested that is based upon physical causal mechanisms and expert judgements combined with hard data rather than world wide blowout statistics.     

Family planning and the health of women and children

Use of family planning has the potential to produce reductions of 10–20% in infant and child mortality. Similar reductions in the mortality rate associated with pregnancy can be expected for mothers. A larger impact on maternal mortality is possible through fertility reduction with decreased exposure to the risks of pregnancy. First births carry excess risks for mothers and children, but these are, by definition, unavoidable. Births to young mothers also pose increased risks for mothers and children. High birth order and older age of mothers probably have been overemphasized as risk factors for children. Very high parity does pose risks to mothers. Poor spacing of births is associated with increased health risks to children. Estimation of mortality reduction through family planning requires knowledge of risk distribution as well as relative risk. High-risk births are relatively rare, and most deaths occur to mothers and babies at average or low risk. Family planning does not avert all high-risk pregnancies because of a lack of acceptance and imperfect use.     

How accurately does the public perceive differences in transport risks?: An exploratory analysis of scales representing perceived risk

This paper probes the extent to which the public accurately perceives differences in transport risks. The paper is based on a survey of a random sample of the Norwegian population, conducted in September 2003. In the survey, respondents were asked: “How safe do you think it is to travel by means of (bus, train, etc.)?” Answers were given as: very safe, safe, a little unsafe, and very unsafe. A cursory examination of the answers suggested that the Norwegian public was quite well informed about differences in the risk of accident between different modes of transport, as well as between groups formed according to age and gender for each mode of transport. This paper probes the relationship between statistical estimates of risk and summary representations of perceived risk more systematically. It is found that the differences in fatality rate between different modes of transport are quite well perceived by the Norwegian public, irrespective of the way in which perceived risk is represented numerically. The relationship between statistical estimates of risk and numerical representations of perceived risk for each mode of transport is more sensitive to the choice of a numerical representation of perceived risk. A scale in which the answer “very safe” is assigned the value of 0.01 and the answer “very unsafe” is assigned the value of 10 is found to perform quite well. When the perception of risk is represented numerically according to this scale, a positive correlation between statistically estimated risk and perceived risk is found in seven of the eight comparisons that were made to determine how well variation in accident rates according to age and gender for car occupants, car drivers, cyclists and pedestrians are perceived.