QUANTITATIVE RISK ASSESSMENT FOR COLLISIONS INVOLVING DOUBLE HULL OIL TANKERS

2021 ◽  
Vol 156 (A2) ◽  
Author(s):  
S A M Youssef ◽  
S T Ince ◽  
Y S Kim ◽  
J K Paik ◽  
F Chang ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Structural Damage ◽  
Human Life ◽  
Quantitative Risk Assessment ◽  
Environmental Damage ◽  
Total Risk ◽  
Formal Safety Assessment ◽  
Environmental Damages ◽  
Oil Tankers ◽  
Double Hull

In recent decades, the safety of ships at sea has become a major concern of the global maritime industries. Ships are rarely subject to severe accidents during their life cycle. Collision is one of the most hazardous accidents, with potentially serious consequences such as the loss of human life, structural damage and environmental damage, especially if large tankers, LNG and/or nuclear-powered vessels are involved. This study presents a Quantitative Risk Assessment (QRA) for double hull oil tankers that have collided with different types of ships. The methodology used to perform the QRA is based on the International Maritime Organization’s (IMO) definition of a Formal Safety Assessment (FSA). Using probabilistic approaches, ship-ship collision scenarios are randomly selected to create a representative sample of all possible scenarios. The collision frequency is then calculated for each scenario. As this is a virtual experiment, the LS-DYNA nonlinear finite element method (NLFEM) is used to predict the structural consequences of each scenario selected. In addition, the environmental consequences are estimated by calculating the size of each scenario’s oil spill. To assess the economic consequences, the property and environmental damages are calculated in terms of monetary units. The total risk is then calculated as the sum of the resultant structural and environmental damages. Exceedance curves are established that can be used to define the collision design loads in association with various design criteria.

Quantitative Risk Assessment for Collisions Involving Double Hull Oil Tankers

2014 ◽  
Vol 156 (A2) ◽  
Keyword(s):  
Risk Assessment ◽  
Structural Damage ◽  
Human Life ◽  
Quantitative Risk Assessment ◽  
Environmental Damage ◽  
Total Risk ◽  
Formal Safety Assessment ◽  
Environmental Damages ◽  
Oil Tankers ◽  
Double Hull

In recent decades, the safety of ships at sea has become a major concern of the global maritime industries. Ships are rarely subject to severe accidents during their life cycle. Collision is one of the most hazardous accidents, with potentially serious consequences such as the loss of human life, structural damage and environmental damage, especially if large tankers, LNG and/or nuclear-powered vessels are involved. This study presents a Quantitative Risk Assessment (QRA) for double hull oil tankers that have collided with different types of ships. The methodology used to perform the QRA is based on the International Maritime Organisations' (IMO) definition of a Formal Safety Assessment (FSA). Using probabilistic approaches, ship-ship collision scenarios are randomly selected to create a representative sample of all possible scenarios. The collision frequency is then calculated for each scenario. As this is a virtual experiment, the LS-DYNA nonlinear finite element method (NLFEM) is used to predict the structural consequences of each scenario selected. In addition, the environmental consequences are estimated by calculating the size of each scenario's oil spill. To assess the economic consequences, the property and environmental damages are calculated in terms of monetary units. The total risk is then calculated as the sum of the resultant structural and environmental damages. Exceedance curves are established that can be used to define the collision design loads in association with various design criteria.

THE DEVELOPMENT OF A RISK ASSESSMENT MODEL TO COMPARE OIL SPILL RISK FOR SINGLE & DOUBLE HULLED FPSOS

2008 ◽  
Vol 2008 (1) ◽  
pp. 725-731
Author(s):  
Nicholas Cavaye ◽  
Gina Waibl
Keyword(s):  
Risk Assessment ◽  
Oil Spills ◽  
Environmental Benefits ◽  
Assessment Model ◽  
Environmental Damage ◽  
Strong Argument ◽  
Accidental Discharge ◽  
Using Data ◽  
Oil Tankers ◽  
Double Hull

ABSTRACT In recent years, following a number of high profile oil spills internationally, there has been an increased focus on improving the safety of oil tankers to prevent the environmental damage caused by oil spills. Regulations developed focus on replacing single hulled trading tankers with a double hulled configuration. However, many of the risks associated with trading tankers do not apply to Floating Production, Storage and Offloading vessels (FPSOs). The risk assessment undertaken for this report compares single with double hull FPSOs, with respect to events causing serious environmental impact. The study considers external and on-board causes of events which may cause serious oil spills including fire, explosion, accidental discharge, grounding, collision and hull failure. The risk assessment comprises a limited quantitative analysis using data from the literature and observations from experience, which are consistently applied to each of the hazardous events identified as relevant. The report also looks at the wider environmental factors associated with single versus double hull FPSOs in order to inform policy makers. The findings indicate that risk profiles of oil tankers are markedly different from FPSOs, and that there is a strong argument that overall environmental risks from a single hull FPSOs are lower than those for a double hulled F?SO. A single sided hull has potentially better structural performance; no risk of inter-hull formation of volatile explosive mixtures; delivers environmental benefits; and has simpler operational requirements than a double sided FPSO. The main advantage for using a double sided hull is the higher collision impact energy it can withstand without releasing oil into the environment.

Toward a New Procedure for the Quantitative Risk Assessment of Double Hull Oil Tankers in Collisions

2015 ◽  
Author(s):  
Samy Adly Mansour Youssef ◽  
Serdar Turgut Ince ◽  
Yang Seop Kim ◽  
Muhammad Faisal ◽  
Jung Kwan Seo ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Residual Strength ◽  
Probabilistic Approach ◽  
Bending Moment ◽  
Quantitative Risk Assessment ◽  
Design Stage ◽  
Loading Ratio ◽  
Ship Collision ◽  
Oil Tankers ◽  
Double Hull

In recent decades, the number of ships increased substantially and it is still expected to continue to increase. Collision risk is one of the most serious accidents that can lead to severe consequences, such as casualty, property damage and environmental pollution. According to the statistics, it is found that the developments in collision avoidance systems and the related regulations have not contributed much to prevent the collision accidents. The aim of the present study is to develop a new methodology for the quantitative risk assessment of double–hull oil tankers. Within the framework of the methodology, a probabilistic approach is introduced to define a relevant set of ship–ship collision scenarios by treating the accidental influencing parameters as random variables. The collision frequency is calculated for each of the selected collision scenarios by considering a double–hull oil tanker collided with different types of striking ships. To predict the resulting collision damage to the struck ship, numerical simulations are conducted for each scenario by performing nonlinear finite element analyses. Based on the calculated risks, exceedance curves are established that can be used to define the collision design loads in association with various design criteria. In addition, to give a more complete picture of the risk assessment, a new method is proposed for assessing the risk of ship’s hull collapse following a collision. The results are formulated in terms of the residual strength index (RSI) and the loading ratio to produce the relationship between residual strength (R) and loading ratio of horizontal bending moment to vertical bending moment (L) and design formulations for predicting the RSI of damaged ship hulls are derived in an empirical manner. As an applied example, a hypothetical Suezmax–class double hull tanker is considered as a struck ship. Collision risks to asset and the environment are assessed. It is considered that the developed methodology can be useful in the early design stage of oil tankers.

Rapid Assessment of Hull Girder Collapse for Corroded Double Hull Oil Tanker After Collision

2016 ◽  
Author(s):  
Sung Hwan Noh ◽  
Jung Kwan Seo ◽  
Jeom Kee Paik ◽  
Samy A. M. Youssef
Keyword(s):  
Finite Element ◽  
Structural Damage ◽  
Rapid Assessment ◽  
Probabilistic Approach ◽  
Hull Girder ◽  
The Alps ◽  
Oil Tankers ◽  
Double Hull ◽  
Oil Tanker ◽  
Probability Density Function Pdf

Corroded tankers might be subjected to a very serious structural damage if involved in collision accidents. For understanding or preventing the collision accidents, various studies are being proposed by researchers to improve the analysis method. In this paper, four types of double hull oil tankers (Panamax, Aframax, Suezmax and VLCC) are used. Probabilistic approach is used to create ship-ship collision scenarios for each target structure and the ultimate longitudinal hull girder strength of the hypothetical oil tanker’s hull cross-section. The ALPS/HULL is used to simulate and is intelligent supersize finite element method (ISFEM) software. A relevant probability density function (PDF) is introduced using the results from finite element simulations of the ship-ship collisions, which is commonly used to predict residual strength.

Quantitative risk assessment of rock slope instabilities that threaten a highway near Canmore, Alberta, Canada: managing risk calculation uncertainty in practice

2020 ◽  
Vol 57 (3) ◽  
pp. 337-353 ◽  
Author(s):  
Renato Macciotta ◽  
Chris Gräpel ◽  
Tim Keegan ◽  
Jason Duxbury ◽  
Roger Skirrow
Keyword(s):  
Risk Assessment ◽  
Decision Making ◽  
Quantitative Risk Assessment ◽  
Environmental Concerns ◽  
Individual Risk ◽  
Total Risk ◽  
Economic Activities ◽  
Rock Falls ◽  
Risk Calculation ◽  
Fall Protection

We present a quantitative risk assessment (QRA) to guide decision-making for selection of rock fall protection strategies. The analysis corresponds to a section of highway near Canmore, Alberta, Canada; where rock falls are common. Environmental concerns, tourism, and economic activities overlap the project area, which increased the complexity of the decision-making process. QRA was adopted to improve highway user safety and minimize effects on natural, social, and economic environments. Uncertainty was associated with hazard and consequence quantification, and the study elicited plausible ranges of input variables for risk calculation. Expected and range in risk were calculated for current conditions and after mitigation. Individual risk to highway users was found to be low, following the limited exposure of any particular individual. Current total risk was calculated at 2.9 × 10−4probability of fatality and a plausible range between 2.0 × 10−5and 5.5 × 10−3. The slope protection configuration selected had a residual total risk between 9.0 × 10−4and 2.9 × 10−6, and a best estimate of 4.5 × 10−5. The risk levels were evaluated against criteria previously used in Canada and were considered an appropriate balance between project costs, public safety, environmental concerns, tourism, and economic activities after mitigation.

On the Use of Proper Fragility Models for Quantitative Seismic Risk Assessment of Process Plants in Seismic Prone Areas

2017 ◽  
Author(s):  
Silvia Alessandri ◽  
Antonio C. Caputo ◽  
Daniele Corritore ◽  
Giannini Renato ◽  
Fabrizio Paolacci ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Seismic Risk ◽  
Structural Damage ◽  
Fragility Curves ◽  
Probabilistic Method ◽  
Quantitative Risk Assessment ◽  
Actual Process ◽  
Consequence Analysis ◽  
Process Plant ◽  
Process Plants

Quantitative Risk Assessment (QRA) is a classical method for the calculation of risk in process plants, which is based on the logic of the consequence analysis. This intrinsically probabilistic method has been thought for classical accident conditions, where the damage events and the relevant consequences start from a preselected component and a standard loss of containment (LOC) and follow all possible scenarios for the calculation of individual and societal risk. This final risk metric is usually expressed in terms of probability of fatality in a specific location of the surrounding area or a certain number of fatalities in the area surrounding the accident. In presence of Na-Tech events, like earthquakes, a multi-source condition can be caused by multi-damage conditions simultaneously involving more than one equipment, which in turn can generate a multiple-chain of events and consequences. In literature, several attempts of modifying the classic QRA approach to account for this important aspect have been formalized without converging toward a unified approach. In this paper, a fragility-based method for Quantitative Seismic Risk Analysis (QSRA) of a process plant is investigated. This method takes into account all possible damage/losses of containment conditions in the most critical equipment, e.g., storage tanks. Fragility curves, which are analytically evaluated for each unit with respect to its seismic damage conditions, are utilized inside the procedure. The Monte Carlo Simulation (MCS) method is then used with the aim to follow all steps of QSRA. In particular, starting from the seismic hazard curve of the site where the plant is placed, a multi-level approach is proposed. In this approach, the first level is represented by the components seismically damaged, whereas the following levels are treated through a classical consequence analysis, including the propagation of multiple simultaneous and interacting chains of accidents. These latter are applied by defining proper correspondences for all relevant equipment between structural damage (i.e., limit states) and LOC events. The application of the method to an actual process plant permits to investigate its high potentiality and the dependency of the risk assessment from the proper fragility models.

scholarly journals Risk Assessment Models to Improve Environmental Safety in the Field of the Economy and Organization of Construction: A Case Study of Russia

2021 ◽  
Vol 13 (24) ◽  
pp. 13539
Author(s):  
Arkadiy Larionov ◽  
Ekaterina Nezhnikova ◽  
Elena Smirnova
Keyword(s):  
Risk Assessment ◽  
Monte Carlo ◽  
Monte Carlo Method ◽  
Rapid Development ◽  
Environmental Safety ◽  
Quantitative Risk Assessment ◽  
Optimal Decision ◽  
Environmental Damage ◽  
The Monte Carlo Method ◽  
The Future

This article assesses risks in order to substantiate the economic and organizational efficiency of housing and industrial construction. This topic is relevant because it is necessary for sustainable development. In Russia, environmental safety in construction and housing, as well as communal services, is poorly developed and not regulated by the legal system. As building construction, housing, and communal services should be based on environmental safety, this topic requires rapid development. Methods related to quantifying environmental risk and making decisions under conditions of uncertainty were studied. A quantitative risk assessment was performed using the Monte Carlo method for pessimistic and optimistic options to prevent environmental damage. The model reproduced the distribution derived from the evidence-based fit. The results of sensitivity analysis are also presented to prove the hypothesis. The selection of the most appropriate probability density functions for each of the input quantities was implemented through settings in a computer program. The simulation modeling results clearly illustrate the choice of the general principle of assessment and the adoption of the optimal decision. In conditions of uncertainty, the decision to choose the optimistic options with high cost (to maintain the reliability of the technical system) but less risk plays a decisive role in the future environmental safety strategies of construction projects. The Monte Carlo method is preferable for environmental impact assessments. In the future, the amended methodology can be applied to raise environmental safety in the field of construction.

Development of Rapid Prediction Method for Residual Strength of Oil Tankers Subjected to Ship-Ship Collision

2018 ◽  
Author(s):  
Seung Jun Baek ◽  
Jung Min Sohn ◽  
Jeom Kee Paik ◽  
Sang Jin Kim
Keyword(s):  
Empirical Formula ◽  
Structural Damage ◽  
Marine Pollution ◽  
Prediction Method ◽  
Financial Loss ◽  
Hull Girder ◽  
Special Skill ◽  
Oil Tankers ◽  
Marine Accidents ◽  
Double Hull

Collision and grounding accidents account for more than half of all accident cases in most cases. Such marine accidents cause severe structural damage to the ship and lead to marine pollution as well as life and financial loss. For preventing the loss of property and pollution, and preparing a countermeasure, it is needed to predict a residual hull girder strength after accident regardless of someone’s special skill. The aims of this study are to i) investigate the residual hull girder strength by quantitative approach with collision location (height and penetration), ii) develop an empirical formula for calculating a residual hull girder strength which whoever can calculate in association with collision locations. In this study, three kinds of ships such as very large crude oil carrier, Suezmax, and Aframax class double hull oil tankers are selected as target struck vessels. And, the Intelligent Supersize Finite Element Method (ISFEM) is applied to assess the residual hull girder strength of damaged structures after collisions. Based on the ISFEM results, an empirical formula for calculation of residual hull girder strength is developed as a function of the collision depth and penetration. The developed formula in this study can be applied by anyone, and rapidly calculate its strength for preventing sequential events (collapse, fuel spill, etc.) after collision.

Methods for analysis of and ways to minimize energy providers’ technology and technical risks

2017 ◽  
pp. 39-48
Author(s):  
Aleksandra Sukhova ◽  
Elena Elizareva
Keyword(s):  
Risk Assessment ◽  
Risk Analysis ◽  
Human Life ◽  
Practical Importance ◽  
Gas Pipeline ◽  
Industrial Safety ◽  
Quantitative Risk Assessment ◽  
Risk Level ◽  
Engineering System ◽  
Gland Seal

Objective: Identifying an accurate quantitative risk assessment. FEC (Fuel and Energy Complex) plants are a high-risk area as they may cause manmade disasters, various accidents, pose a threat to human life and environment. In addition, the Russian energy industry is noted for its high complexity and social responsibility. Its specific feature is that it is not always possible to make an accurate quantitative risk assessment reasonably in advance and its degree determination methods are not well enough developed. In view of the above, there are some difficulties in minimizing the risks and estimating risk management costs. There has been a recent trend in improved current legislation on industrial safety and Rostechnadzor (Federal Environmental, Industrial and Nuclear Supervision Service of Russia) oversight and supervision activity practice toward implementing a risk-based approach using the risk analysis methods. It allows optimizing the methods and frequency of inspections made by regulatory bodies depending on the risk level of facilities supervised. Methods: The (accident) risk analysis is performed as a certain scientific justification set forth using qualitative and quantitative analysis of a potential accident likelihood, consequences of its occurrence, and identification of the weakest points in the engineering system or complex. Using fault tree analysis, this article identifies hazards and assesses the high-pressure gas pipeline loss of containment risk, one of the events possible for an energy provider in operation. Results: Based on the risk analysis, there has been a proposal to replace gland seal valves with bellows seal valves noted for their optimum relationship between the unit reliability, cost and sophistication level. In case the facilities with gland seal valves remain in operation, improved production process monitoring is recommended using gas leak detectors and automatic interlocking devices. Practical importance: The measures proposed will allow minimizing the gas pipeline loss of containment risk.

scholarly journals DOUBLE HULL OIL TANKERS—HOW EFFECTIVE ARE THEY?

1993 ◽  
Vol 1993 (1) ◽  
pp. 745-751
Author(s):  
Virgil F. Keith
Keyword(s):  
Control Systems ◽  
Oil Spill ◽  
Structural Damage ◽  
Oil Spills ◽  
State Of The Art ◽  
North Slope ◽  
First Line ◽  
Safety Measures ◽  
Oil Tankers ◽  
Double Hull

ABSTRACT The groundings of the Exxon Valdez on Bligh Reef in Prince William Sound, spilling more than 10 million gallons of Alaska North Slope crude, and the American Trader off Huntington Beach, spilling almost 400,000 gallons of Alaska North Slope crude, suggest that the construction of oil tankers be re-examined with respect to a design which could reduce both the number and magnitude of oil spills. This paper discusses state-of-the-art tanker technology with respect to spill prevention, effectiveness, and cost. The design features include double hulls, centralized bunker tankers, vacuum-retaining valves, cargo control systems, auxiliary thrusters, electronic charting, and the retransmission of the ship's position. Double hulls provide the highest probability of surviving damage, either from a collision or grounding, with no loss of cargo. Use of double hulls can reduce oil spill incidence by 90 percent in grounding situations and by 75 percent in collisions. The oil spill from the American Trader could have been completely avoided by double hull construction. The arrangement provides spaces below the cargo tanks and on the vessel's sides solely for the carriage of ballast water when the tanker is in ballast condition. These tanks are empty when the tanker is loaded and then also act as the first line of defense in the event of structural damage to the cargo tanks. Tanker design is integrated with port safety measures, including vessel monitoring systems, in this total spill prevention analysis. All aspects of the tanker transportation system are considered.

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