Modeling the release, spreading, and burning of LNG, LPG, and gasoline on water

Current interest in the shipment of liquefied natural gas (LNG) has renewed the debate about the safety of shipping large volumes of flammable fuels. The size of a spreading pool following a release of LNG from an LNG tank ship has been the subject of numerous papers and studies dating back to the mid-1970s. Several papers have presented idealized views of how the LNG would be released and spread across a quiescent water surface. There is a considerable amount of publicly available material describing these idealized releases, but little discussion of how other flammable fuels would behave if released from similar sized ships. The purpose of this paper is to determine whether the models currently available from the United States Federal Energy Regulatory Commission (FERC) can be used to simulate the release, spreading, vaporization, and pool fire impacts for materials other than LNG, and if so, identify which material-specific parameters are required.

The review of the basic equations and principles in FERC's LNG release, spreading, and burning models did not reveal a critical fault that would prevent their use in evaluating the consequences of other flammable fluid releases. With the correct physical data, the models can be used with the same level of confidence for materials such as LPG and gasoline as they are for LNG.     

Accident investigation reporting deficiencies related to organizational factors in machinery space fires and explosions

Careful accident investigation provides opportunities to review safety arrangements in socio-technical systems. There is consensus that human intervention is involved in the majority of accidents. Ever cautious of the consequences attributed to such a claim vis-à-vis the apportionment of blame, several authors have highlighted the importance of investigating organizational factors in this respect. Specific regulations to limit what were perceived as unsuitable organizational influences in shipping operations were adopted by the International Maritime Organization (IMO). Guidance is provided for the investigation of human and organizational factors involved in maritime accidents. This paper presents a review of 41 accident investigation reports related to machinery space fires and explosions. The objective was to find out if organizational factors are identified during maritime accident investigations. An adapted version of the Human Factor Analysis and Classification System (HFACS) with minor modifications related to machinery space features was used for this review. The results of the review show that organizational factors were not identified by maritime accident investigators to the extent expected had the IMO guidelines been observed. Instead, contributing factors at the lower end of organizational echelons are over-represented.     

Formal safety assessment based on relative risks model in ship navigation

Formal safety assessment (FSA) is a structured and systematic methodology aiming at enhancing maritime safety. It has been gradually and broadly used in the shipping industry nowadays around the world. On the basis of analysis and conclusion of FSA approach, this paper discusses quantitative risk assessment and generic risk model in FSA, especially frequency and severity criteria in ship navigation. Then it puts forward a new model based on relative risk assessment (MRRA). The model presents a risk-assessment approach based on fuzzy functions and takes five factors into account, including detailed information about accident characteristics. It has already been used for the assessment of pilotage safety in Shanghai harbor, China. Consequently, it can be proved that MRRA is a useful method to solve the problems in the risk assessment of ship navigation safety in practice.     

Overview of critical risk factors in Power-Two-Wheeler safety

Power-Two-Wheelers (PTWs) constitute a vulnerable class of road users with increased frequency and severity of accidents. The present paper focuses of the PTW accident risk factors and reviews existing literature with regard to the PTW drivers’ interactions with the automobile drivers, as well as interactions with infrastructure elements and weather conditions. Several critical risk factors are revealed with different levels of influence to PTW accident likelihood and severity. A broad classification based on the magnitude and the need for further research for each risk factor is proposed. The paper concludes by discussing the importance of dealing with accident configurations, the data quality and availability, methods implemented to model risk and exposure and risk identification which are critical for a thorough understanding of the determinants of PTW safety.     

Analysis of the marine traffic safety in the Gulf of Finland

The Gulf of Finland (GOF) is geographically situated between Finland and Estonian waters. The seafloor varies between deep and shallow and a number of underwater rocks exist in the Finnish archipelago area. The marine traffic has been growing fast during the last years in this area, especially due to the rapid increase of the transportation of various cargoes to Russia and the transport of oil from Russia. In this paper the safety of the marine traffic in the GOF area is analysed. First a detail accident statistics during the last 10 years are described and thereafter the risk of ship collisions is studied by theoretical modelling in two locations. Finally the results of the theoretical models are compared with actual accident statistics. The results reveal that grounding is the dominating accident type in these waters and typically about 11 groundings take place annually, of which about one is a tanker grounding. For collision the highest risks are caused by the passenger ship/RoPax ships traffic between Helsinki and Tallinn together with the high traffic intensity eastwards/westward to and from Russian harbours. The theoretical collision models give good results when compared with the accident statistics. AIS data is utilised in the theoretical models to calculate the geometric collision probabilities.     

Taxonomic analysis of Chinese power transmission and distribution industry accidents based on hazard components

Power transmission and distribution were critical components for the development of Chinese economy. As in all sectors of the economy it was important to reduce the accidents rate as low as possible. This research adapted accident taxonomic analysis to identify the main factors associated with accidents and then provided accident prevention countermeasures in the industry in China. Because of lack of systematic power transmission and distribution accident information in China, 324 power grid accidents from 1961 to 2008 were collected through a wide range of sources and classified according to hazard elements which were target and threat, hazard element and initiating mechanism respectively and then the initiating mechanisms were further classified by hazard types. Through taxon structures the direct and indirect factors were identified in the industry accidents and strategies of accident prevention were recommended based on them. The taxon structures also can be further developed to form tailored safety checklist for the front workers.     

A summary of some experimental data on LNG safety

In a recent paper, Luketa-Hanlin reviewed the information in the public domain related to LNG safety. The purpose of this paper is to supplement that work by providing a summary of the experimental information that Advantica has collected on LNG behaviour over the course of the last 30 years. This summary includes previously unpublished information obtained as a result of a number of collaborative projects. Subjective comments are also made on the status of modelling for each of the topic areas and, in a discussion, views are provided on those areas where there are currently gaps that may have a major impact on evaluating the individual or societal risks associated with LNG operations.     

United states regulations for siting LNG terminals: problems and potential

The regulations being applied to liquefied natural gas (LNG) import terminal siting in the United States are reviewed. There are no requirements for exclusion zones to protect the public from LNG spills onto water. Serious problems with current practices used to determine exclusion zones on the land-based part of the facility are identified. Many of the questions that are considered relate to the use of computational fluid dynamic (CFD) models, which appear to offer the best potential for realistic modeling to determine vapor cloud exclusion zones that result from LNG spills into impounded areas with or without dispersion in the presence of other obstacles to the wind flow. Failure to use CFD models, which are already approved by the regulation, and continued use of practices which have been demonstrated to be in error, raises important questions of credibility as well as denies the applicant full use of scientific tools that are available to optimize the design of such facilities so as to best provide for safety of the public.     

The role of LNG in energy supply

This paper reviews the current status of base-load LNG plants involved in international trade. In the historical review of the development of of the LNG industry brief references are made to peak-shaving LNG plants. The paper also describes the complex co-operative effort required to organize international LNG projects, and presents technical information concerning the refrigeration aspects of base-load LNG projects. The information includes brief reviews of liquefaction cycles, storage tanks, types of ships, receiving terminals, and the potential for utilizing the refrigeration available in revaporized LNG.     

Minimising earliness and tardiness by integrating production scheduling with shipping information

Minimisation of earliness and tardiness is known to be critical to manufacturing companies because it may induce numerous tangible and intangible problems, i.e. extra storage cost, spacing, risk of damages, penalty, etc. In literature, earliness and tardiness is usually determined based on order due date, generally regarded as the time of delivering the finished products to the customers. In many papers, delivery time and cost required are usually simplified during the production scheduling. They usually assume that transportation is always available and unlimited. However, transportation usually constructs a critical portion of the total lead time and total cost in practice. Ignoring that will lead to an unreliable schedule. This is especially significant for electronic household appliances manufacturing companies as the studied company in this paper. In general, they usually rely on sea-freight transportation because of the economic reasons. As different sea-freight forwarders have different shipments to the same destination but with different shipping lead time, cost and available time. Adequately considering this shipping information with the production scheduling as an integrated model can minimise the costs induced by earliness and tardiness and the reliability of the schedule planned. In this paper, a two-level genetic algorithm (TLGA) is proposed, which is capable of simultaneously determining production schedule with shipping information. The optimisation reliability of the proposed TLGA is tested by comparing with a simple genetic algorithm. The results indicated that the proposed TLGA can obtain a better solution with lesser number of evolutions. In addition, a number of numerical experiments are carried out. The results demonstrate that the proposed integrated approach can reduce the tardiness, the storage cost, and shipping cost.     

Analysis of the effect of car size on accident injury probability using automobile insurance data

The Highway Loss Data Institute (HLDI) compiles injury and collision claim information from major insurance companies. These data have indicated that a disproportionately large number of injury claims are made for small cars. As a result, it might be concluded that small cars increase injury risk to their occupants. Recent advertisements by a major automobile manufacturer suggest a similar conclusion should be drawn from these data. In this paper it is shown that the apparent higher injury risk attributed to small cars can reflect the behavior of persons driving small cars. The number of injury claim accidents per collision claim accident is examined as an alternative measure of injury risk. Possible problems in interpretation are discussed.     

浅谈国内LNG产业链发展前景

天然气作为一种清洁低碳能源,对我国调整能源结构和节能减排具有重要的战略意义.我国天然气资源储量仅占全球1.7％,且主要分布着人口稀少的西部地区,因此对海外LNG需求量巨大.我国的LNG产业起步较晚,但发展迅速,目前已建成6个LNG接收站,并具有一定的转运能力.本文从我国现状出发,从LNG资源开采、运输、商业模式及应用等方面分析了国内LNG产业发展的前景,并指出天然气发电将会极大推动LNG产业的发展.     

Cost-effectiveness criteria for marine oil spill preventive measures

Oil tanker accidents resulting in large quantities of oil spills and severe pollution have occurred in the past, leading to major public attention and an international focus on finding solutions for minimising the risks related to such events. This paper proposes a novel approach for evaluating measures for prevention and control of marine oil spills, based on considerations of oil spill risk and cost effectiveness. A cost model that incorporates all costs of a shipping accident has been established and oil tanker spill accidents have been further elaborated as a special case of such accidents. Utilising this model, novel implementation criteria, in terms of the Cost of Averting a Tonne of oil Spilt (CATS), for risk control options aiming at mitigating the environmental risk of accidental oil spills, are proposed. The paper presents a review of previous studies on the costs associated with oil spills from shipping, which is a function of many factors such as location of spill, spill amount, type of oil, etc. However, ships are designed for global trade, transporting different oil qualities. Therefore, globally applicable criteria must average over most of these factors, and the spill amount is the remaining factor that will be used to measure cost effectiveness against. A weighted, global average cleanup cost of USD 16,000/tonne of oil spilt has been calculated, considering the distribution of oil tanker traffic densities. Finally, the criteria are compared with some existing regulations for oil spill prevention, response and compensation (OPA 90).     

Models relating traffic safety with road environment and traffic flows on arterial roads in Addis Ababa

This paper presents the study carried out to develop accident predictive models based on the data collected on arterial roads in Addis Ababa. Poisson and negative binomial regression methods were used to relate the discrete accident data with the road and traffic flow explanatory variables. Significant accident predictive models were found with a number of significant explanatory variables. The results show that the existing inadequate road infrastructure and poor road traffic operations are the potential contributors of this ever-growing challenge of the road transport in Addis Ababa. The results also indicate that improvements in roadway width, pedestrian facilities, and access management are effective in reducing road traffic accidents.     

A systems approach to accident causation in mining: An application of the HFACS method

This project aimed to provide a greater understanding of the systemic factors involved in mining accidents, and to examine those organisational and supervisory failures that are predictive of sub-standard performance at operator level. A sample of 263 significant mining incidents in Australia across 2007–2008 were analysed using the Human Factors Analysis and Classification System (HFACS). Two human factors specialists independently undertook the analysis. Incidents occurred more frequently in operations concerning the use of surface mobile equipment (38%) and working at heights (21%), however injury was more frequently associated with electrical operations and vehicles and machinery. Several HFACS categories appeared frequently: skill-based errors (64%) and violations (57%), issues with the physical environment (56%), and organisational processes (65%). Focussing on the overall system, several factors were found to predict the presence of failures in other parts of the system, including planned inappropriate operations and team resource management; inadequate supervision and team resource management; and organisational climate and inadequate supervision. It is recommended that these associations deserve greater attention in future attempts to develop accident countermeasures, although other significant associations should not be ignored. In accordance with findings from previous HFACS-based analyses of aviation and medical incidents, efforts to reduce the frequency of unsafe acts or operations should be directed to a few critical HFACS categories at the higher levels: organisational climate, planned inadequate operations, and inadequate supervision. While remedial strategies are proposed it is important that future efforts evaluate the utility of the measures proposed in studies of system safety.     

A risk analysis of winter navigation in Finnish sea areas

Winter navigation is a complex but common operation in north-European sea areas. In Finnish waters, the smooth flow of maritime traffic and safety of vessel navigation during the winter period are managed through the Finnish–Swedish winter navigation system (FSWNS). This article focuses on accident risks in winter navigation operations, beginning with a brief outline of the FSWNS. The study analyses a hazard identification model of winter navigation and reviews accident data extracted from four winter periods. These are adopted as a basis for visualizing the risks in winter navigation operations. The results reveal that experts consider ship independent navigation in ice conditions the most complex navigational operation, which is confirmed by accident data analysis showing that the operation constitutes the type of navigation with the highest number of accidents reported. The severity of the accidents during winter navigation is mainly categorized as less serious. Collision is the most typical accident in ice navigation and general cargo the type of vessel most frequently involved in these accidents. Consolidated ice, ice ridges and ice thickness between 15 and 40 cm represent the most common ice conditions in which accidents occur. Thus, the analysis presented in this article establishes the key elements for identifying the operation types which would benefit most from further safety engineering and safety or risk management development.     

Multiday driving patterns and motor carrier accident risk: a disaggregate analysis.

A method has been developed to estimate the relative accident risk posed by different patterns of driving over a multiday period. The procedure explicitly considers whether a driver is on duty or off duty for each half hour of each day during the period of analysis. From a data set of over 1,000 drivers, nine distinct driving patterns are identified. Membership in the patterns is determined exclusively by the pattern of duty hours for seven consecutive days; for some drivers an accident occurred on the eighth day while others had no accident, therefore each pattern can be associated with a relative accident risk. Additional statistical modeling allowed the consideration, in addition to driving pattern, of driver age, experience with the firm, hours off duty prior to the last trip and hours driving on the last trip (either until the accident or successful completion of the trip). The finding of the modeling is that driving patterns over the previous seven days significantly affect accident risk on the eighth day. In general, driving during the early and late morning (e.g., midnight to 10 A.M.) has the highest accident risk while all seven other multiday patterns had indistinguishable risk. Consecutive hours driven also has a significant effect on accident risk: the first hour through the fourth hour having the lowest risk with a fluctuating increase in risk to a maximum beyond nine hours. Driver age and hours off duty immediately prior to a trip do not appear to affect accident risk significantly. These findings quantitatively assess the relative accident risk of multiday driving patterns using data from actual truck operations. Further research is recommended in the areas of refining model structures, adding explanatory variables (such as highway type), and testing more complex models.     

Car driver casualty rates in Great Britain by type of car

Since 1989, the British STATS19 national road accident reporting system has included the Vehicle Registration Mark (VRM). This allows the basic vehicle record to be augmented with details such as the date of first registration and codes that specify the vehicle's make and model. In order to examine the influence of car type upon the driver casualty rate, this paper groups car models into six types, ranging from 'Minis and Superminis' to '4x4s and people carriers (pc)'. Exploratory analyses of data from accidents that occurred between 2001 and 2005 show that the driver casualty rate falls markedly with size of car. In car-car collisions, the rate also rises markedly with the size of the other car. The car's year of first registration also influences the casualty rate, and represents the influence of changes in the characteristics of new cars. Statistical models are fitted to identify the separate influences on a driver's risk of injury in a car-car collision of the type and registration year of the driver's car and the type and registration year of the other car in the collision. The analysis is extended to include collisions with other vehicles such as lorries and buses.     

Multiple Stimuli-Response Polychromatic Carbon Dots for Advanced Information Encryption and Safety

Optical information encryption and safety have aroused great attention since they are closely correlated to data protection and information safety. The development of multiple stimuli-response optical materials for constructing large-capacity information encryption and safety is very important for practical applications. Carbon dots (CDs) have many gratifying merits, such as polychromatic emission, diverse luminous categories, and stable physicochemical properties, and are considered as one of the most ideal candidates for information protection. Herein, carbon core, functional groups, solvents, and other crucial factors are reviewed for outputting polychromatic emission of multiple luminous categories. In particular, substrate engineering strategies have been emphasized for their critical role in yielding excellent optical features of multiple luminous categories. High-capacity information encryption and safety strategies are reviewed by relying on the rich optical properties of CDs, such as polychromatic emission, multiple luminous categories of fluorescence, afterglow, and upconversion, as well as external-stimuli-assisted optical changes. Some perspectives for preparing excellent CDs and further developing information security strategies are proposed. This review provides a good reference for the manipulation of polychromatic CDs and the development of next-generation information encryption and safety.     

Sources of error in road safety scheme evaluation: a method to deal with outdated accident prediction models

This paper considers the errors that arise in using outdated accident prediction models in road safety scheme evaluation. Methods to correct for regression-to-mean (RTM) effects in scheme evaluation normally rely on the use of accident prediction models. However, because accident risk tends to decline over time, such models tend to become outdated and the estimated treatment effect is then exaggerated. A new correction procedure is described which can effectively eliminate such errors.