High Impact Low Probability Research Articles

Risk-informed decision making of safety investments by using the disproportion factor

To improve risk informed decision making, a systematic approach is developed. The goal is to analyze and to evaluate safety investments aimed at mitigating and preventing major accidents involving e.g. hazardous materials that might trigger significant financial losses and fatalities. A formulation, explicitly using a disproportion factor, is proposed as a simulation exercise approach to this end. The disproportion factor can be used by any private and public investor to bias decision-makers toward safety. This is especially interesting for deciding about the prevention of high impact low probability (HILP) accidents.Furthermore experimental simulations have been performed on realistic data to test the proposed decision model and to provide general recommendations. Several types of accidents were considered and the impacts of technical and financial parameters on the disproportion factor, possibly making a safety investment profitable from an economic perspective, are also investigated and discussed in this paper.

Assessment of domino effect: State of the art and research Needs

High-impact low-probability (HILP) accident scenarios in industrial sites are raising a growing concern. Domino effect was responsible of several catastrophic accidents that affected the chemical and process industry, as well as critical infrastructures for energy as oil refineries. However, there is still a poor agreement on assessment procedures to address escalation hazard resulting in domino scenarios. The present study presents a review of the work done in the last 30 years in the field, and a critical analysis of available tools and knowledge gaps concerning domino effect assessment. The analysis of scientific publications concerning domino effect in the process industry resulted in a database of more than 60 documents, addressing three main issues: past accident analysis, models for equipment damage, risk assessment and safety management of domino scenarios. The methods, models and tools developed make now possible the quantitative assessment of domino scenarios in risk analysis and in safety management of industrial sites. Nevertheless, a number of open points still remain, where existing tools may be improved and uncertainty may be reduced.

Quantitative assessment of domino and NaTech scenarios in complex industrial areas

Since the late 80s the application of quantitative risk assessment to the issue of land-use planning with respect to major accident hazards emerged as a topic to be addressed within the safety assessment of chemical and process plants. However, in the case of industrial clusters or complex industrial areas specific methodologies are needed to deal with high-impact low-probability (HILP) events. In the present study, innovative methodologies developed for the quantitative assessment of risk due to domino and NaTech scenarios are presented. In recent years a set of models for the calculation of equipment damage probability were developed. A specific effort was dedicated to the improvement of models for the calculation of equipment damage probability in these accident scenarios. In the present study, the application of these models to case-studies was analyzed. The results of the improved models obtained for NaTech quantitative assessment were compared to previous results in the literature. A specific innovative approach was developed to multi-level quantitative assessment of domino scenarios, and its potential was analyzed. The results were examined also evidencing the role and the progress with respect to the pioneering work started on these topics by Franco Foraboschi.

An analysis of tropical cyclones impacting the Southeast United States from a regional reanalysis

Extreme events (low probability–high impact events) such as tropical cyclones can result in loss of life, substantial socio-economic impacts and disrupt the natural environment. Atmospheric reanalysis products provide a means for understanding these events and their impacts. This paper examines the near-surface winds and precipitation from 42 observed land-falling tropical cyclones between 1979 and 2000 in a new high-resolution (10 km) reanalysis for the Southeast United States. It is shown that the near-surface wind speeds in the tropical cyclones are underestimated by almost half compared to the observed best-track data. The regional reanalysis resolves the pattern of coastal precipitation associated with the tropical cyclones; however, the average storm maximum precipitation is too high resulting in large storm-related precipitation farther inland than observed. Possible reasons for the deficiencies are discussed.

Analyzing abrupt and nonlinear climate changes and their impacts

AbstractThe Earth system shows the tendency to change in nonlinear and sometimes abrupt ways; small changes in external forcing can lead to large and perhaps irreversible changes in outcome. The prospect of crossing important ‘tipping points’ and realizing their impacts poses unique challenges to decision makers within society, hoping to avoid damaging anthropogenic influence on Earth systems. Abrupt and nonlinear changes are by their very nature highly uncertain and difficult to predict, and so hard to avoid or adapt to. After briefly introducing key concepts in nonlinear dynamics, we summarize paleoclimate evidence for past abrupt and nonlinear changes in major Earth systems such as, ocean and atmospheric circulation patterns, sea ice and terrestrial ice sheets, atmospheric composition, and the terrestrial biosphere. For each of these systems we then review observational, theoretical, and modeling evidence for potential future abrupt changes, and associated impacts. We outline the extra challenges that are faced in predicting abrupt or nonlinear as opposed to more gradual climate change, and in providing a risk analysis for their impacts on Earth and societal systems. We examine the potential for early warning systems of abrupt change, and discuss differences in attitude to risk which may dictate societal response to low probability–high impact events. Finally, we outline the promising directions of research needed to better quantify the risk of abrupt and nonlinear climate change. WIREs Clim Change 2011 2 663–686 DOI: 10.1002/wcc.130This article is categorized under: Assessing Impacts of Climate Change > Evaluating Future Impacts of Climate Change

The Northern Rock crisis: a multi‐dimensional problem waiting to happen

In August 2007, the UK experienced its first bank run since 1866. Northern Rock had adopted a business model (heavy reliance on securitization and wholesale market funding) that exposed itself to a low-probability-highimpact (LPHI) risk. The chapter argues that it was an accident waiting to happen in that there were fundamental fault lines in the institutional architecture for dealing with failing banks in the UK. In particular, there was an inconsistency in the deposit protection scheme, no special insolvency arrangements for dealing with failing banks, and no ex-ante Resolution procedure. There were also serious failings in the supervision of Northern Rock, and in the split of responsibilities between the Treasury, Bank of England, and the Financial Services Authority (FSA).

Preparing for the big one [supply chain management

The range of potential high impact-low probability (HILP) disruptions to the operations of retailers, manufacturers, transportation carriers, and all others involved in the supply chains of goods and services is infinite. They can be classified as follows: random phenomena, accidents of all kinds, and international disruptions. Each type of disruptions should be anticipated and defended against differently. For companies, resilience is the measure of their ability to, and speed at which they can, return to their normal performance level - production, services and fill rate - after an HILP disruption. Building a resilient supply chain can help a company survive in the face of a calamitous disruption.

Social scenarios of sea level rise

In the next 100 years a rise of the sea level will force The Netherlands to strengthen its coastal protection. Conservative forecasts mention rises up to 1m in this time. Low probability—high impact forecasts suggest a rise of 2m in the first 100 years and a further rise by 3m in the next 100 years. Higher dikes can protect the densely populated areas below sea level in The Netherlands to a limited extent only. If Dutch society gets caught in a downward cultural, economic and social spiral, improving the defence against the sea will become difficult. If, on the other hand, Dutch society shares in a development towards a more positive cultural, economic and social order, it is possible that the investments for improving the system of dikes and dunes can be realised without too much difficulty and that a relatively safe type of protection against the sea can be built. A substantially higher sea level may provide opportunities for producing electricity by using water power in The Netherlands. The article provides a mental exercise, based on a limited number of assumptions.