The emission of greenhouse gases has tightened up in the shipping industries, since the International Maritime Organization established the Emission Control Area (ECA), to reduce the emission of NOx and SOx. It results in an increase of Liquefied Natural Gas (LNG) as an alternative fuel for merchant vessels. However, the LNG-fueled ship should be verified with respect to reliability and its safety due to the high risk of natural gas. This work aims to establish the scenario of gas leak accident, and the critical zone due to fire spreading. The variables of leak size, leak location, wind direction and wind speed were included into the scenario. The probabilistic approach also applied to determine the scenario. This study provides the release duration which is associated to the ignition probability. The Latin Hypercube Sampling was used to generate the credible scenario. Finally, Computational Fluid Dynamics (CFD) analysis of fire release scenarios was performed by using a commercial package software, Kameleon FireEx. The numerical simulation results show the thermal radiations which consisted of several levels of heat intensity. The size of critical zone can be determined from the contour of thermal radiation.

The Great East Japan Earthquake that occurred in Japan in 2011, an innumerable number of buildings in the coastal part of the east side of Japan suffered catastrophic damage, and medical facilities in coastal areas have become dysfunctional because of the significant damage incurred due to the tsunami. And land routes are not passable, but there are records of support activities utilizing water areas such as sea and river networks being extremely effective in such disaster conditions. Therefore, as one of the effective methods of medical support in the affected area immediately after the disaster, a Floating Medical Support System (hereafter Medi-float) on big disaster that can be accessed from the water area was proposed. In the near future, the area along the Arakawa River is expected to be seriously damaged by the earthquake directly under the Tokyo metropolitan area. Therefore, by installing a Medi-float that can perform medical support activities from the water area to the land without being damaged by an earthquake, since Medi-float performs medical support activities in cooperation with medical facilities on land area, preventable death is reduced. In previous studies, a procedure to estimate the facilities scale and select a suitable site for Medi-float practically based on GIS data such as the number of collapsed buildings in the target area, distribution of injured people due to the earthquake were presented. However, even if Medi-float is installed in the target area, it cannot be denied that there is a shortage of medical facilities. In consideration of smooth transportation outside the region and cooperation with surrounding medical facilities, it is hoped that a concrete and realistic medical support system by Medi-float will be established. Therefore, in this study, in order to grasp the time it takes for the injured to be transported to the medical facility and the congestion status of the medical facility, the target area was divided into 250m meshes and a time-series simulation was performed. Specifically, the distribution of injured people during a disaster was calculated on a mesh basis from the number of buildings collapsed and the number of fires. And the transport time of the injured people is calculated from the distance between each mesh and the medical facility, the movement of the injured people in consideration of the congestion status of the medical facility was simulated, necessity of cooperation between medical facilities and wide area transportation was clarified, the effect of Medi-float, which is active in the disaster area, was also evaluated.

Blast panels are integral structures in offshore topside modules to protect personnel and safety critical equipment by preventing the escalation of events due to hydrocarbon explosions. As such, blast panels are expected to retain their integrity against any blast loading and subsequent hydrocarbon fire. Most of the blast panels currently installed in offshore structures have been designed using simplified calculation approaches such as the Single Degree of Freedom (SDOF) models, as recommended by offshore design codes and industry recommended practices. In this paper, the Non-Linear Finite Element Analysis (NLFEA) technique is used to simulate the structural response of corrugated panels subjected to blast loading. Detailed numerical analyses allow identifying the limits of the SDOF approach, and exploring different design options to optimize the structural response of corrugated blast panels. The blast load profile corresponding to an explosion is one of the most important factors to consider in the structural analysis. The mechanism of hydrocarbon explosions is very complex, and the corresponding blast load profile intimately depends on the type of explosion, the congestion and the structural confinement. A sensitivity analysis is performed to investigate the influence of the blast pulse shape, and in particular to evaluate the effect of the maximum peak pressure and the exposure time. To explore the benefits of introducing higher strength steels in demanding offshore applications, pressure-impulse diagrams have been derived for different high strength steel grades. In our analysis, (ultra)high strength cut-to-length plates from hot rolled coil are proposed to optimize the design of the blast panel whilst preserving the structural performance under demanding load conditions.

The new generation of value-added low carbon-low manganese-niobium microalloyed structural steels for both low and high yield strength, energy absorption, fatigue and fracture resistant applications is under development for offshore and arctic materials engineering applications. These materials engineering considerations are shifting designers to consider new lower cost and more robust construction materials even for low yield strength applications require improved fatigue, fracture arrest and toughness performance. The civil engineering and end user community demand structural reinforcing bars, shapes, beams and plates with improved energy absorption and fatigue properties. With more severe climatic conditions evolving every day, demands also necessitate improved fire and seismic resistance, yield-to-tensile ratio consistency, improved bendability and weldability. These attributes are difficult to obtain from steel producers today with their current higher carbon microalloyed steel approaches and hot rolling practices. There is a global shift in motion to low C-Nb-Mn bearing construction steels displacing traditional materials. The technological and metallurgical advancements of value-added niobium (Nb) microalloyed thermo-mechanical controlled process (TMCP) plate steels have been further developed to meet more demanding fatigue, fracture and low temperature toughness end user requirements. Niobium enables achievement of substantial grain refinement and grain size uniformity when the plate is rolled with the proper reduction, thermal schedule and process metallurgical operational practices. The effects of microalloying elements on the continuous cooling transformation behavior must be carefully controlled during the process metallurgy of the reheating and rolling process to successfully achieve the desired mechanical properties. TMCP applications have been successfully developed in numerous product sectors with thickness exceeding 120 mm. Since the very fine grained microstructure improves toughness and increases the yield strength, this Nb-TMCP process enables the required tensile properties with the growing trend to leaner chemical composition designs (less than 0.10%C) and excellent toughness properties. From an operational cost perspective, in today’s very competitive market environment, there exists a huge opportunity for structural offshore and arctic plate producing steel mills to improve their profitability by thoroughly assessing a shift to lower carbon and manganese steels in their product mix. Through the adoption of these lower carbon Nb-containing structural materials, several design and/or manufacturing companies are initiating new offshore steel designs that will further provide improved overall lifetime and cost performance at reduced maintenance expense. These high strength plate steels offer the opportunity to manufacture complex heavy-lift and fatigue-critical components for larger offshore structures without increasing the weight of the platforms.

Despite regulations becoming more and more stringent, significant quantities of gas are still flared around the world every year. Indeed, for safety reasons, flaring remains a usual practice in oil and gas production in cases of process upset. For instance, emergency shutdown, when the unit must be depressurized in a short period of time, most of the gas inventories are flared to limit as much as possible the potential consequences of fire and explosion within the facility. With the increase of the global demand for energy and especially in Liquefied Natural Gas (LNG), the recent development of Floating Liquefied Natural Gas unit (FLNG) has raised new challenges concerning flare stack design. Since FLNG facilities handle large flammable gas quantities the flare stack needs to be designed considering much more stringent cases. It results in an increased length of flare stack, to reduce the radiation effects on personnel and equipment. The thermal response of the flare structure needs also to be accounted for in the design, in addition to other load cases such as piping and structural weight or vessel accelerations. To accomplish the structural design of the flare stack, the engineers will have to convert the radiative heat fluxes from the flame into the resulting temperature of the structure exposed. Indeed, temperature is the parameter that can be used as a thermal load case in any finite element analysis calculation code. Current temperature mapping methodologies applied on projects are not exhaustive and are often based on a simplified approach which is now challenged by operators and certification bodies who require more detailed verifications on flare structure heating during continuous or emergency flaring. Moreover, such simplified modelling approaches tends to overestimate thermal protection to mitigate the heat radiation impact. The proposed approach described in this paper will address these points through a multidisciplinary workflow to form a flexible, simple and robust technical methodology to be applied during project execution. The proposed approach will assess heat radiation and temperature calculations in a spatial-temporal reference including the dynamic response. This transient approach is more attractive as computed temperatures will be lower than steady-state approach results which are the usual engineering practice, especially for accidental loading cases, such as emergency depressurization, where the flare release can decrease quickly.

The potential risk of an offshore processing facility is the major important part in the oil and gas industry due to its limited space causing difficulties in evacuation. An offshore processing facility is normally exposed to flammable oil and gas in the operating phase. Especially, uncontrolled hydrocarbon leaks or ruptures of the equipment present main threats. These failures can lead to fire and explosion disaster. Some studies have proposed fire and explosion assessment methodologies and made fire and explosion assessment tools. These tools can provide risk assessments result using physical effect modelling software and following the related standards or engineering practices according to accident scenarios. Nevertheless, existing fire and explosion assessment procedures are still not comprehensive enough to applicate a specific process due to its complexity and are not clear which stage in a project is appropriate for applying it. This paper focuses only on explosion accidents and discusses the development of an explosion risk analysis procedure possible to apply at process flow diagram (PFD) level. The explosion risk analysis procedure using PFD has 6 steps; modelling of a process, scenario selection, inventory calculation, frequency calculation, consequence modelling and risk estimation. It starts at modelling of a specific process using process simulation software, HYSYS. The process modelling can be optimized by the existing methods and finally provide the PFD for the specific process. In the scenario selection step, the information required to perform a risk analysis is identified. The inventory calculation conducts to calculate the inventory of a defined segment after sizing of the equipment in the PFD. The frequency calculation consists of leak frequency and ignition probability. The leak frequency can be calculated with historical database and the ignition probability can be calculated with a specific ignition probability model. The consequence modelling is conducted by using physical effect modelling software, PHAST. It can provide the distance to specified overpressure. Finally, at the risk estimation step, the risk results are evaluated. This procedure can help to applicate a specific process easily and provide explosion risk assessment tool at PFD level. This paper conducts the case study for a liquefied natural gas floating production storage offloading (LNG-FPSO) which is one of the representative offshore processing facilities. Especially, a natural liquefaction process in a LNG-FPSO, which liquefies the processed natural gas to store in a storage tank of a LNG-FPSO, is the most important process in terms of cost and risk. In the situation the most of ongoing or prospective projects for LNG-FPSO adopt dual mixed refrigerants (DMR) liquefaction process, the representative configurations of the DMR liquefaction processes are evaluated and compared. It can help decision making through providing which configuration has an advantage in terms of explosion accidents.

Axial thermal gradients in flexible pipes is a relatively novel area of research. New studies are putting focus on how the structural integrity of flexible pipes can be challenged by axial thermal gradients [1]. Significant axial thermal gradients occur, in particular, during start-up (heating) and shut-down (cooling) of the pipe in the vicinity of transition zones from pipe directly exposed to the surrounding environment, i.e. water or air, to thermally insulating parts, e.g. external anti-wear and fire protection layers, bend restrictors, bend stiffeners, and buoyancy modules. Along with differences in thermal expansion coefficients of the different pipe layers, the axial thermal gradients can cause significant shear stress in the interfaces between pipe layers. Thereby, axial thermal gradients may potentially cause relative axial displacement, or a slip displacement, between e.g. the pressure sheath and the pressure armor layers. In this way, axial loads in the pipe layers may not be properly transferred to, and thereby supported by, the tensile armor layer. A primary concern is the risk of e.g. pressure sheath pull-out of the end-fitting or carcass tearing failures. The present paper partially builds upon, and extends, the results presented earlier [1], primarily concerned with interface shear loads and slip displacements between the inner pipe layers, i.e. carcass, pressure sheath, and pressure armor, and extends that study in several ways. 1) Reconsiderations of the thermomechanical coupling between the radial and the axial spatial direction, and a detailed scale analysis, leads to a more rigorous derivation of the shear stress in the carcass / pressure sheath and pressure sheath / pressure armor interfaces in response to axial thermal gradients. These results deviate from the earlier published result only in terms of Poisson’s ratio dependent numerical pre-factors. 2) The established theoretical framework includes a thorough coupling between the interface shear stresses, and the radial, axial, and azimuthal normal stresses. This allows for an exhaustive evaluation of the mechanical state of the pipe in both pre-slip and post-slip conditions, including residual states. 3) The results are generalized to transient thermo-viscoelastic analysis, which is critical for conservatism due to the viscoelastic stress relaxation of the polymeric pressure sheath material during heating, cooling, and thermal cycling. Possible failure modes due to axial thermal gradients are currently not covered explicitly by design codes and conventional qualification testing. The model presented in this article can form basis for risk evaluations related to axial thermal gradients, input to formulations of design codes, and engineering design tools. The model contains the mechanisms that govern criticality in relation to axial thermal gradients, and its implications on interface shear stress, potential interface slip, and forces in the pipe, thereby also providing insights into possible mitigation actions for related failure modes.

In offshore operations, overpressure of pressure vessels can arise in case of emergencies like fire or malfunction of valves. This situation can cause physical damages of the vessel and, operation break. Thus, managing overpressure is important in terms of safety of offshore facilities. To handle the overpressure problems, the rapid depressurization, so-called ‘Blowdown’, is used. During depressurization, temperature of internal fluids in a vessel get decreases by the expansion of the fluids. Predicting decrease of the temperature is critical to choose the material of a pressure vessel. Overdesign without the prediction leads to the rapidly decreasing profit margins. For these reasons, the analyzing dynamic behavior of thermodynamics properties like temperature is required for material selection and design verification during depressurization. In this study, a dynamic model for depressurization was developed to simulate thermodynamics behavior in a vessel during depressurization including low temperature phenomena. The model contains non-equilibrium zone between phases, heat transfer between walls and fluids in the vessels. The heat transfer coefficient between internal vapor and wall was calculated from a combined convection that includes the both natural and forced convection. This study includes the calculation of liquid/wall heat transfer coefficient. During depressurization, liquid in the vessel becomes boiling closed to surface of the wall because the temperature of the wall is higher than the boiling point of the liquid. This phenomenon can be described as ‘nucleate boiling’, causes decreasing convective heat transfer coefficient from inner wall to the liquid in the vessel. Using the proper correlations about this phenomenon, the calculated coefficient made this study get closer to reality. The results were compared to experimental and simulation data from literature and it shows this model can properly estimate the thermodynamic property change in a vessel.

In recent years, there has been unprecedented interest shown in the Arctic region by the industry, as it has become increasingly accessible for oil and gas exploration, shipping, and tourism. The decrease in ice extent in the Arctic has renewed the interest in the Northern Sea route, necessitating further research to evaluate the adequacy of the equipment and appliances used on vessels traversing in polar waters. In the oil and gas industry, exploration and production vessels and platforms are highly dependent on the piping facilities for rendering their intended function, and therefore, flow assurance is extremely crucial. If the winterization of pipes is not done properly, this could lead to massive cost overruns due to unplanned production shutdowns or even worse, accidents. A temperature drop between the different areas of the production facilities will change the thermodynamic properties of the fluids, and could cause the processing of the crude oil to become inefficient. The introduction of the Polar Code by the International Maritime Organization (IMO) attempts to mitigate some of the risks endangering the vessels in polar waters. The Polar Code is scheduled to take effect on 01.01.2017, and applies to all vessels traversing in polar waters. The Polar Code requires that all machinery installations and associated equipment required for the safe operation of ships shall be protected against the effect of freezing and increased viscosity of liquids, and that working liquids shall be maintained in a viscosity range that ensures the operation of the machinery. To account for this, the heat loss of pipes carrying liquid (water for fire extinguishing and hydraulic fluid amongst others) needs to be estimated and mitigating measures must be taken. In this study, methodology from the refrigeration industry is applied to calculate the estimated time to freeze for liquids in pipes. The methodology is adapted for use in the maritime industry, and results are presented in this study. The methodology used was found to be quite flexible, allowing for the calculation of complex scenarios and shapes, including the effect of varying degrees of insulation on pipes, and can easily be applied for approximating the best suitable method of insulating pipes to ensure flow assurance and maintain fluid properties at desired levels. Tables estimating the time-to-freeze for insulated pipes of different diameters and insulation thicknesses exposed to cross-winds of varying speeds are provided. The methodology is found to have great potential, and should be investigated further with experiments. The objective of the paper is thus to introduce the methodology for cold-climate engineering and use it for practical analysis of realistic estimates of insulated and non-insulated piping.

Maritime accident statistics show that the majority of accidents/incidents are attributed to human errors as the initiating cause. Some studies put this as high as 95% of all accidents (collision, grounding, fire, occupational accidents, etc). The traditional way to investigate human factors in maritime industry is the statistical analysis of accident data. Although this analysis can provide key findings, it cannot capture the causal relationship between performance shaping factors and human performance in the everyday routine work, and is not suitable to be used in the individual assessment of cadets. To reveal the effects of human factors in maritime and assess the performance of cadets, a full-mission simulator is widely used. Different scenarios such as bad weather, day and night environment, different traffic load, etc. can be simulated. The fine details of the cadet performance can be recorded in the simulator during the assessment. As a result, other than performance failure, the near misses can also be detected. Additionally, a number of cadets can go through the same scenarios at the same time and between-subjects comparison is enabled. Besides the operations recording provided by the simulator, biosignal-based tools can additionally help in the human factors study in maritime. The existing methods include palmer perspiration, electrocardiography, etc. However, the psychophysiological states that can be recognized by these methods are limited. Electroencephalogram (EEG) biosignals can be used to directly assess the “inner” mental states of subjects. Nowadays, since the EEG devices become portable, easy to setup, and affordable in price, EEG-based tools can be used to assess psychophysiological state of subjects. Using the sensors during performing the task we can recognize the cadet/captain’s emotions, attentiveness/concentration, mental workload, and stress level in real time. In this work, we propose a real-time brain state recognition system using EEG biosignals to monitor mental workload and stress of cadets during simulator-based assessment. Currently, the proposed and implemented system includes stress and mental workload recognition algorithms. The EEG-based mental state monitoring can reflect the true “inner” feelings, stress level and workload of the cadets during the simulator-aided assessment. The time resolution is up to 0.03 second. As a result, we can analyze the recognized brain states and the corresponding performance and behavior recorded by the simulator to study how human factors affect the subject’s performance. For example, we can check is there any correlation of the cadet’s stress level and performance results. Finally, the proposed EEG-based system allows us to assess whether a cadet is ready to perform tasks on the bridge or needs more training in the simulator even if he/she navigated with few errors during the assessment.

As large offshore drilling facility, Floating Production Storage and Offloading (FPSO) faces with the risk of oil & gas leakage and subsequent effects (e.g. fire and explosion). In order to assess FPSO gas leakage and subsequent chain effects risk scientifically, a FPSO topsides is analyzed, and Failure Model and Effect Analysis (FMEA) method is applied to find out which equipment has high Risk Priority Number (RPN). The results show that gas washing pry of FPSO in operation phase has high RPN and needs significant attention. In this paper, CFD-model of FPSO topsides is established based on computational fluid dynamics (CFD) theory. The leak rate of gas with specified hole diameter is calculated based on appropriate leak source model according to the actual operating conditions of gas washing pry. Then based on the simulation results diffusion behavior is analyzed, as well as distribution law of gas and the hazardous area of gas of gas washing pry under the leakage conditions. Furthermore, one explosion model is selected, and then damaging over-pressure of explosion on each equipment surface and the variation trend and influence scope of explosion over-pressure are derived to evaluate personnel and equipment risk. Targeted technical measures will be put forward to reduce risk.

Safety Lifecycle is described in IEC61508 and IEC61511, but more detailed engineering procedure than IEC61508 and IEC61511 is required for real design and manufacture of safety system for offshore project. For the turret national research project, more detailed design procedure was applied for the design of turret. First of all, the nodes are defined based on EUC (Equipment Under Control) units and the hazards are analysed by 3 methodologies — Hazard Checklist, HAZOP and FMEA during hazard analysis phase. Then the risk are analysed quantitatively by LOPA methodology. To produce the safety requirement specification for function, the cause & effect, the logic diagram and IO list will be produced. The isolation countermeasures in case of explosion and fire and the SIFs (Safety Instrumented Function) in LOPA report and the process shutdown interlocks will be included in the cause & effect and the logic diagram will be developed based on this cause & effect. The safety requirement specification for safety will be developed by exSILentia from exida. Based on the safety requirement specification, the Functional Design Specification, the Safety Validation Plan including the test specification and test plan, the system configuration will be developed during the Basic Design phase and then IO list & terminal allocation, application software implementation, panel drawing will be developed during the detailed design.

The ships and offshore structures are exposed to inherently the risk of fire and explosion. These fire and explosion, accident caused by grave consequences not only to the ships and offshore platforms on the sea but the environment all mankind. The aim of this paper is to focus on an optimization of water deluge and mist spray system locations subjected to jet on the ships and offshore platforms. A trustworthy set of fire scenarios is identified and classified using probabilistic sampling methods calling for Latin Hyper Sampling. These events of fire are numerically calculated for selected scenarios by the computational Fluid Dynamic (CFD) code using a KFX. The Water Deluge Location Index (WLI) is then calculated by using the frequency and consequence of fire scenarios. And then, WLI are utilized to prioritize the optimal locations of water deluge and mist spray systems. The recommended methodology believes that can increase to certainties in the design procedure of unreliability and can regard the cost-effectiveness of safety design.

Ships and offshore structures are exposed to various types of extreme and accidental events including fire, explosion, collision, dropped objects, etc. These events lead to nonlinear structural consequences. This paper focused on grated-steel deck structures subjected to dropped-objects. The aim of this paper is to confirm the nonlinear impact response of grated-steel deck structures. An experimental study was undertaken in a dropped object test facility and LS-DYNA nonlinear finite element computations were also performed for the corresponding test models. It is noted that nonlinear finite element analyses are useful in the analysis of the nonlinear impact structural responses as long as the modeling techniques are adequate. The conclusions developed in this paper will be informative in the safety design of ships and offshore structures.

This work is motivated by the need to identify the fire and explosion risk on LNGCs developed by Daewoo Shipbuilding & Marine Engineering Co., Ltd. (DSME) because the main engines are designed to use highly pressurized natural gas (about 300 bar), which has caused vague fears of fire and explosion risks. In this context, to identify the risk of fires and explosions quantitatively caused by ignitions of unintended leaked gas from fuel gas lines, a FERA was carried out for the LNGCs [1]. This paper, as a part of the FERA, presents the results of a preliminary investigation on the effect of introducing the highly pressured fuel gas system into LNGCs on the fire and explosion risk especially in the cargo compressor room. This study is conducted in a comparative way considering the risk contribution of each parameter that could impact on the fire and explosion risk in LNGCs. The effect of the highly pressured fuel gas is indirectly taken into account by the change of the initial leak rate in the system. To identify effects of the considered parameters quantitatively, dozens of simulations for the selected gas dispersion, explosion and fire scenarios were carried out using FLACS and KFX. Based on the results from the simulations, it is concluded that, in case of the LNGCs, the effects of the initial large leak rate due to the high pressure in the fuel gas pipes on fire and explosion risk are not significant compared with the other parameters’ effects.

The present study compares the progressive collapse approach with the traditional temperature screening method on determination of PFP requirements at topside offshore structures. The advantage to evaluate the consequences of fire scenarios on the global integrity and stability of topside modules can be revealed by a substantial reduction of the required amount of PFP, and consequently significant cost savings for operators, when compared to the traditional approach. In the case study presented in this paper, there is a reduction of 79% in PFP allocation.

To reduce environmental impact and to manage weight in shipping and offshore, lightweight structures are becoming increasingly important. A critical issue for loadbearing structures is their structural fire integrity. It is generally evaluated by loaded furnace fire resistance tests based on ISO 834. As part of the EU project BESST, a series of such tests were performed with typical lightweight fiber reinforced polymer (FRP) composite sandwich structures. The purpose was to determine whether structural fire integrity is sensitive to the design load, design method and safety factor against buckling. In particular was examined whether the temperature at the interface between the exposed laminate and the core is critical for structural integrity and how it depends on the applied loading. Independence of the applied load would make performance solely a matter of heat transfer, which would significantly reduce necessary testing. The tests were carried out with starting point in an insulated sandwich panel system, certified as a 60 minute Fire Resisting Division (FRD-60) for high-speed craft in accordance with the Fire Test Procedures (FTP) Code. The structure consisted of 1.3 mm glass fiber reinforced polyester laminates surrounding a cross linked PVC foam core called Divinycell H80 (80 kg/m 3 ). It was constructed for a 7 kN/m design load, which is the loading applied in the FTP Code furnace test for high-speed craft. Hence, with a conventional safety factor against buckling of 2.5 it was designed to resist a critical load of 17.4 kN/m. With basis in this design, tests were performed with structures where the thickness of the laminates or core had been altered and with adjusted safety factor against the applied loading. In addition, a test was performed with a stiffened panel. Firstly it was noted that 60 minutes of fire resistance was not achieved in most of the tests, which was a consequence of an alteration in the FTP Code test procedures. The FRD-60 structure used as starting point was certified before the 2010 edition of the FTP Code was ratified. This harmonized the test procedure between laboratories and gave a slightly tougher temperature development than when the structure was certified. However, the test results are still valid and show a small variation in the time to failure in the tests with unstiffened sandwich structures, ranging between 51 and 58.5 minutes. Changing the safety factor from 2.5 to 1.5 resulted in a relatively small decrease in time to failure of 3 minutes. The stiffened test showed that structural resistance is better achieved by use of stiffeners than by thick laminates. Furthermore, applying this as a design principle and using a safety factor of 2.5 leaves a test variation between 55 and 58.5 minutes. The temperature at the exposed laminate-core interface was quite similar in the tests at the time of failure. This excludes the test when the laminate thickness was increased as a measure for structural improvement. In conclusion, the test series shows that fire resistance bulkhead testing of insulated FRP composite panels can be simplified and does not have to be performed with varying design loads. To achieve conservative evaluation, a design concept should be evaluated by testing the panel designed for the highest applicable load level, not by testing a weak panel at 7 kN/m loading. This applies to non-stiffened solutions.

An outer shield breach is the most common form of damage that can occur to a subsea flexible pipe during both installation and operation. Definitive and accurate detection and location of such damage is imperative in triggering the appropriate repair response. The overall aim is to minimise corrosion damage to the carbon steel strength elements in the pipe annulus, which occurs from the resulting ingress of seawater. GE Oil & Gas, in collaboration with Photon Fire Ltd have developed a new method of detecting seawater in a subsea flexible pipe annulus. This paper describes a novel breach detection system developed to monitor pipes using very low energy electrical signals appropriate for use in hazardous areas. The technique provides an enduring record of the occurrence of a breach and the extent of the subsequent flooding. A brief outline of the development programme is presented. The work involved determining the sensing technique used, development of appropriate electronic instrumentation, the optimised method for installing the sensor into the riser, and bespoke connection to the instrumentation. A prototype system, approved for use in Hazardous Area ATEX zone zero has been implemented on midscale pipe samples and the transient and steady state ‘scans’ of the pipe have been investigated. A summary of the test results and a proposed testing regime is presented. Results show that using this technique can accurately determine that a breach has occurred in the wall of the riser and the extent of the flooding.

The lithium-ion battery (LIB) is widely used in portable devices, power tools and electric vehicles, which becomes one of the most important moving power sources. However, inevitable internal short circuits may cause the pressure inside the battery rising, leading to fire or intensive explosion. In this paper, a finite element (FE) model is established to reasonably capture the major explosion behavior of 18650 battery, one of the most prevailing battery models in electric vehicles, caused by internal short circuit. An explosive load is applied to the 18650 battery FE model based on ABAQUS platform to simulate the internal short circuit. The FE model includes key components such as anode part, cathode part, multi-layered separator and the outside shell. Mechanical parameters are taken from previous studies [1] as well as current mechanical testing, with the consideration of temperature, strain rate and anisotropy effect. Result may provide future in-depth studies to study the lithium-ion battery explosion which are not available from the real-world experiment such to guide the optimal design for safe battery manufacturing.

The paper presents the background and major ideas behind the computer program USFOS. The program is today widely used by the offshore industry to assess the resistance of oil and gas installations against abnormal environmental loads and accidental actions, such as ship collisions, fires and explosions. The assessment is normally performed in the accidental limit states; i.e. substantial yielding, buckling, partial collapse may take place, but the structure should maintain overall integrity. The features and concepts and models adopted in USFOS have also proved to be very useful in the analysis of totally different edifices. A few examples of this are given in the paper.