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Hydrogen is a promising zero-emission fuel that could play a key role in the transition towards a more sustainable economy. It is regarded as a possible fuel for the future that could replace traditional fossil fuels and reduce the consequent amount of greenhouse gas emissions. In contrast with the undeniable benefits introduced by the use of hydrogen as a fuel, its hazardous properties rise concern from the safety standpoint. A potential loss of integrity of the storage equipment might lead to severe consequences such as fires and explosions. The current investigation aims at quantifying the impact of the outcomes of an unexpected hydrogen release from the storage vessels designed for hydrogen-powered buses. A comparative analysis is carried out considering the different conditions in which hydrogen is currently stored on board: as a high-pressure gas, as a cryogenic liquid or as a cryo-compressed gas. According to the operating conditions, a set of accident scenarios that may follow the release of hydrogen is identified and an event tree analysis is carried out to determine the resulting dangerous phenomena. The impact of such phenomena is assessed in terms of damage distances. The results of the study demonstrate the high hazardousness of cryo-compression and highlight that liquid and compressed hydrogen are the preferable solutions from a safety standpoint. [ABSTRACT FROM AUTHOR]

Decarbonization represent one of the main challenges of the maritime transport sector for the near future. As recent international environmental regulations have set more stringent emission limits, the use of liquefied natural gas (LNG) as alternative ship fuel has proven to be a viable and less-polluting solution, compared to conventional oil-based fuels. However, LNG is a highly flammable substance and safety aspects need to be assessed thoroughly, especially for its use on board passenger ships. Two different gas engine concepts are typically used for ship propulsion: Low-Pressure Dual Fuel (LPDF) and High-Pressure Dual Fuel (HPDF) engines. Regardless of the gas engine technology, the fuel gas supply system process equipment is located inside a specific enclosed space, the fuel preparation room (FPR), that can be sited below deck. Given this background, this study aims to investigate the consequences of LNG pool fires occurring inside a confined space, assessing the influence of different operating conditions. Credible loss of containment events were identified to define the characteristics of LNG pools. Furthermore, LNG pool fires were simulated using the fire dynamic simulator (FDS) to estimate the radiation heat flux received by the process equipment installed inside the FPR and to assess the possibility of experiencing accident escalation on board. To evaluate the effect of forced mechanical ventilation of the FPR, two different cases were modelled: one assuming the standard functioning of the ventilation system, while the other one considered a halted air supply inside the FPR with a working exhaust system only. The outcomes of this study provide useful data for the consequence estimation of small-scale LNG pool fires occurring inside enclosed spaces, also addressing the possibility of accident escalation on board LNG-fuelled ships. [ABSTRACT FROM AUTHOR]

Wildfires approaching the Wildland-Industrial Interfaces can be a serious threat for industrial items located at the plant boundary. These items are typically storage tanks involving large amounts of hazardous substances. Ensuring their integrity is of paramount importance to prevent the wildfire spread inside the industrial plant, avoiding the occurrence of major accidents such as fires, explosions and toxic releases. A methodology for the evaluation of safety distances between tanks and vegetation for the protection from wildfire hazard was developed and applied to a case study. The outcomes provide useful information for an effective emergency response planning in the case of wildfire. Moreover, the results obtained rise concern about the appropriateness of clearance areas between the vegetation and industrial areas currently adopted. [ABSTRACT FROM AUTHOR]

A methodology to conduct the Response Gap Analysis (RGA) for offshore oil spill emergency activities was developed, able to identify, for a given area and a given time period, if the response, which depends on the combination of the environmental factors affecting the performance of the contingency actions, is favourable, impaired, or ineffective. The necessity for offshore oil and gas operators to perform a RGA derives from the provisions of the Directive 2013/30/EU on safety of offshore oil and gas operations. In this Directive, "oil spill response effectiveness" means the effectiveness of spill response systems in combating an oil spill, on the basis of the "analysis of the frequency, duration, and timing of environmental conditions that would preclude a response. Furthermore, the assessment of oil spill response effectiveness is to be expressed as a percentage of time that such conditions are not present and is to include a description of the operating limitations placed on the installations concerned as a result of that assessment". Firstly, a gap analysis was conducted, aimed at highlighting the state of the art of RGA. The various literature reports on RGA are based on different environmental factors, as well as on different response strategies. A detailed analysis of the available information allowed identifying 9 environmental factors to be included in RGA: the wind speed, the wave height, the air temperature, the wind chill, the superstructure icing, the daylight / darkness conditions, the horizontal visibility, the cloud ceiling, and the sea ice coverage. In addition, also the shoreline distance and the bathymetry, which are location specific factors, could impair the response. Thus, a total number of 11 "environmental factors" is taken into account in the new RGA methodology. The definition of threshold values to be applied to each environmental factor was also addressed. In literature, usually two limit values are adopted and three zones are identified: a green zone, where the factor is favourable to the response; a yellow zone, where it is marginal, and a red zone, where it is unfavourable. Technical reports were analysed in order to retrieve the limit values of the environmental factors mentioned. Thus, a set of threshold values was proposed for mechanical recovery, application of dispersants by vessel and by aircraft, and in-situ burning. As a further step, the criteria adopted to combine the environmental factors in order to evaluate the effectiveness of the response were investigated. All the most recent studies identify for the response a green zone for the favourable response, a yellow zone corresponding to the impaired response, and a red one, where the response is ineffective. This criterion is adopted in the RGA method developed in the present study. The RGA methodology was implemented in a software code, which was applied to a case study area, allowing the validation of the RGA procedure. [ABSTRACT FROM AUTHOR]

Wildland Urban Interface (WUI) fires are posing tremendous management challenges in terms of civil protection and fire mitigation. Many critical factors are contributing and increasing the risk at the WUI, such as the presence of all sorts of fuels whose hazard is poorly characterized and disregarded by residents, the existence of vulnerable elements in houses and industrial installations and the absence of standards that deal with the WUI problem at the homeowner/ property scale. The WUIVIEW project aims at developing an innovative risk management tool that will help WUI communities to adapt in order to face the new generation of forest fires. This is being done by designing, setting up and testing a virtual workbench service for the performance-based analysis of fire environments in the surroundings of buildings at the WUI. In this framework, a methodological approach for the assessment of LPG domestic tanks vulnerability under fire exposure at the WUI has been developed. The present work provides a demonstration of such methodology through a realistic case study, together with an overview of the WUIVIEW project activities. [ABSTRACT FROM AUTHOR]