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Industrial accidents can be triggered by natural hazards (as earthquakes, floods, lightning, and extreme temperatures) which can result in fires, explosions, or release of hazardous substances. These high impact accidents are called NaTech (Natural Hazards Triggered Technological Accident). NaTech can determine huge damages and their rapid growth in the latter years is also associated with climate change evolution. In this context, refineries are among the facilities majorly affected by NaTech and the presence of large amounts of hazardous materials makes easier to envisage potentially catastrophic scenarios. Risk assessments should include NaTech scenarios, and this should come with the availability of robust and efficient screening tools for safety engineering applications. Due to the complexity of extreme natural events, no general or reference models are officially available, leaving to the analyst the duty to estimate aspects such as probability of occurrence of an extreme natural event. Extreme events weather databases are also often incomplete, reporting data on past natural events with insufficient information for risk assessment purposes. This is particularly true for extreme winds. This paper applies a modified version of a literature reference model, based on the analysis of the occurrence of extreme winds on a Lat-Long quadrant classification. A grid choice dependence is shown, highlighting the variation of extreme winds likelihood of extreme winds on 3 Italian refineries located close to the sea. By changing the reference area for extreme winds analysis, the screening analysis leads to different results. [ABSTRACT FROM AUTHOR]

The main goal of process safety is to analyse and reduce risks related to industrial processes in order to ensure that the final risk on people and environment is as low as possible. To establish whether the risk related to the process is tolerable or not it is therefore necessary to calculate the risk associated with the events under consideration and to compare the result with the selected tolerability criteria: this is the common approach used in Quantitative Risk Assessment (QRA) analysis. The risk associated with an event, whatever is its nature (on people, on the environment or financial) is a function of the likelihood of the event (generally expressed in events/year) and the consequences (expressed in terms of damage) of the event itself. The aim of this article is to focus on the first parameter (frequency evaluation): the main goal is not to write a math paper on frequency calculation (there are a lot of articles and specialised sources in the scientific literature that deal with the theory of probability calculation and, therefore, it would not make sense to focus on math) but to report the main conceptual errors in frequency calculation found in existing risk analysis reports. Frequency calculation depends especially on the quality of the performed hazard identification study (e.g HAZOP) and on the proper identification of the common cause failures present within a complex system which, if not properly identified, can lead to an incorrect assessment of the likelihood of a dangerous event. The final scope is to show how it is possible to fall into pitfalls during frequencies calculation if the hazards identification is not properly performed and if dependencies between safeguards are not properly assessed: usually these errors lead to obtain frequency values that have no physical meaning. [ABSTRACT FROM AUTHOR]

In recent years, hydrogen use has dramatically increased, mainly due to its growth in status as a transportation fuel. A new wave of interest in hydrogen has also been generated by actions taken by the European Union regarding ecological transition, promoting "hydrogen valleys" for the local production and use of the so-called green hydrogen. To achieve a safe and sustainable growth in the use of hydrogen as an alternative energy vector, every actor in the hydrogen value chain shall be aware of its inherent hazards, so that the appropriate preventive and protective measures required to mitigate the associated risks are enforced. This article shall review the main physical properties of hydrogen, and how these relate to some safety challenges such as its low ignition energy and its unusually wide flammability range. Attention is given also to the high laminar burning velocity of hydrogen-air mixtures, and how this parameter influences the sizing of deflagration vents which shall be protected against confined cloud explosions. Hazards associated with handling of liquified hydrogen are discussed as well (such as the risk of cryogenic burns). This article shall review the main physical properties of hydrogen, and how these relate to some safety challenges such as its low ignition energy and its unusually wide flammability range. Attention is given also to the high laminar burning velocity of hydrogen-air mixtures, and how this parameter influences the sizing of deflagration vents which shall be protected against confined cloud explosions. Hazards associated with handling of liquified hydrogen are discussed as well (such as the risk of cryogenic burns). In the article, a HAZOP (Hazard and Operability) analysis is carried out on a typical electrolysis unit for hydrogen production, together with its hydrogen storage tank, identifying a number of potentially hazardous scenarios. For each scenario, the effectiveness of existing safety barriers is discussed, also with respect to international codes and engineering best practices, and additional preventive and protective measures are illustrated. [ABSTRACT FROM AUTHOR]

Il pastiche gaddiano è un fenomeno particolarmente complesso, poiché stravolge tanto gli elementi linguistici quanto quelli iconografici della tradizione letteraria contaminandoli e, di fatto, riscrivendoli. Un esempio di questo fenomeno è certamente la riscrittura dei tòpoi della tradizione lirica amorosa che l'Ingegnere compie ribaltando i canoni dello stilnovismo – che già nei secoli precedenti erano mutati dando vita ai rifacimenti di maniera –, attraverso la deformazione dell'immagine di Amore e della domina angelicata. Partendo dalla lettura di alcuni passi tratti da articoli, racconti e romanzi, l'intento di questo saggio è sottolineare come, mediante la manipolazione dei tòpoi canonici dello stilnovismo, Gadda pervenga a delineare una propria dichiarazione di poetica in una commistione di toni tragici, umoristici e caricaturali. [ABSTRACT FROM AUTHOR]