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

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.

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QUANTITATIVE RISK ASSESSMENT FOR COLLISIONS INVOLVING DOUBLE HULL OIL TANKERS

The International Journal of Maritime Engineering ◽

10.5750/ijme.v156ia2.924 ◽

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.

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Probabilistic Selection of Ship-Ship Collision Scenarios

Volume 2A: Structures, Safety and Reliability ◽

10.1115/omae2013-10316 ◽

2013 ◽

Cited By ~ 3

Author(s):

Samy A. M. Youssef ◽

Jeom K. Paik ◽

Yang Seop Kim ◽

Min Soo Kim ◽

Fai Cheng

Keyword(s):

Sampling Technique ◽

Random Variable ◽

Quantitative Risk Assessment ◽

Design Stage ◽

Density Distributions ◽

Design Loads ◽

Ship Collision ◽

Accident Scenarios ◽

Probability Density Distributions ◽

Double Hull

Within the framework of quantitative risk assessment and management in the design stage, it is essential to select relevant sets of accidental scenarios, while a huge number of possible scenarios are obvious. The current industry practices are likely based on prescriptive approaches for the most unfavorable accidental scenarios. However, these approaches are often inadequate for obvious reasons because they may result in too large values of design loads in some cases but they may underestimate design loads in other cases. In the present study, an innovative method using probabilistic approaches is suggested to select relevant sets of ship-ship collision accident scenarios which represent all possible ones. Historical database for each of individual collision parameters which is dealt with as a random variable have been collated and are analyzed by statistical methods to characterize the probability density distributions. A sampling technique is then applied to select collision scenarios. Applied examples to a double hull oil tanker are presented to demonstrate the applicability of the developed method.

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Quantitative Risk Assessment for Collisions Involving Double Hull Oil Tankers

10.3940/rina.ijme.2014.a2.288 ◽

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.

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Probability risk assessment of landslides: A case study at Finneidfjord

Canadian Geotechnical Journal ◽

10.1139/t08-055 ◽

2008 ◽

Vol 45 (9) ◽

pp. 1250-1267 ◽

Cited By ~ 31

Author(s):

Mark J. Cassidy ◽

Marco Uzielli ◽

Suzanne Lacasse

Keyword(s):

Risk Assessment ◽

Probabilistic Approach ◽

Quantitative Risk Assessment ◽

Historical Case Study ◽

Historical Case ◽

Second Moment ◽

Integrated Risk Assessment ◽

First Order Second Moment ◽

Probabilistic Risk Assessments

Probabilistic risk assessments are increasingly being considered the most appropriate framework for engineers to systematically base decisions on hazard mitigation issues. This paper aims to show the advantages of a quantitative risk assessment by application to a historical case study. The generalized integrated risk assessment framework has been applied retrospectively to a submarine landslide that occurred in 1996 near the village of Finneidfjord in northern Norway. Over 1 million cubic metres of predominantly quick clay was displaced. Even though it was triggered underwater on the embankment of the Sørfjord, the retrogressive nature of the slide resulted in it encroaching 100–150 m inland. The triggering mechanism is believed to have been the placement of fill, from a nearby tunnelling project, on the foreshore of the embankment. This paper is a retrospective quantitative evaluation of the risk to the neighbouring houses, the persons in those houses, and the persons in open spaces caused by the placement of increasing levels of embankment fill. A probabilistic approach, making use of second-moment modelling and first-order second-moment approximation is adopted. It aims to demonstrate the advantages of this type of risk assessment in understanding complex and integrated hazards, particularly those in populated environments.

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

Volume 3: Structures, Safety and Reliability ◽

10.1115/omae2016-54667 ◽

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.

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Mitigation of Risks Associated with Gas Pipeline Failure by Using Quantitative Risk Management Approach: A Descriptive Study on Gas Industry

Journal of Marine Science and Engineering ◽

10.3390/jmse9101098 ◽

2021 ◽

Vol 9 (10) ◽

pp. 1098

Author(s):

Avoce Honga Abdoul Nasser ◽

Petro Dickson Ndalila ◽

Edem A. Mawugbe ◽

Melaine Emmanuel Kouame ◽

Mioumnde Arthur Paterne ◽

...

Keyword(s):

Risk Assessment ◽

Oil And Gas ◽

Quantitative Risk Assessment ◽

Design Stage ◽

Management Approach ◽

Gas Industry ◽

Gas Dispersion ◽

Pipeline Networks ◽

Safety Studies ◽

Design Protection

Risk assessment is one of the main tools that oil and gas industries use to assess the hazards and risks in their facilities worldwide. Qualitative and quantitative risk assessments are carried out at various phases of the process industry: conceptual stage, design stage, construction stage, operational stage, decommissioning stage, etc. The quantitative risk assessment is directed during the detailed design stage to decide the spacing and layout out of equipment for safe operation and maintenance of oil and gas industries. The equipment layout and spacing are based on the safe distances are to be carried out on various design safety studies. In this work, a study was carried out on upstream onshore natural gas gathering stations and associated equipment and pipeline networks. The fire, explosion assessment, and toxic gas dispersion are conducted to evaluate how it affects people, assets, and the environment. Whether the design protection systems are adequate to mitigate the consequences or any additional measures to reduce risk to an acceptable level is analyzed.

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

International Oil Spill Conference Proceedings ◽

10.7901/2169-3358-2008-1-725 ◽

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.

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A New Method for Assessing the Safety of Ships Damaged by Grounding

10.3940/rina.ijme.2012.a1.218 ◽

2012 ◽

Vol 154 (A1) ◽

Keyword(s):

Residual Strength ◽

Structural Damage ◽

Damage Index ◽

Sampling Technique ◽

Damage Scenario ◽

Strength Performance ◽

Damage Scenarios ◽

Longitudinal Strength ◽

Oil Tankers ◽

Double Hull

The primary aim of the present study is to propose an innovative method for assessing the safety of ships which have suffered accidental or in-service damages. Only a small number of probable scenarios for accidental or in-service damage representing all possible damage scenarios are selected using a sampling technique in which the random variables affecting the damage are probabilistically characterized. A damage index for the corresponding damage scenario is defined as a function of damage characteristics such as location and extent of the damage. The residual strength performance of a ship with the corresponding damage scenario can then be calculated by analytical or numerical methods. Once this process has been carried out for each of the damage scenarios selected, a diagram relating the residual strength performance to the damage index (abbreviated as the R-D diagram) can be established. This diagram will be very useful for a first-cut assessment of a ship’s safety immediately after it has suffered structural damage. The diagram can also be used to determine acceptance criteria for a ship’s safety against accidental or in-service damage. An applied example is shown to demonstrate the applicability of the proposed method in terms of developing a diagram between the ultimate longitudinal strength versus grounding damage index for four types of double-hull oil tankers – VLCC, Suezmax, Aframax, and Panamax.

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