Quantitative evaluation of the safety barriers to prevent fired domino effect

A simplified methodology was developed for the assessment of fire protection barriers and to support the Quantitative Risk Assessment (QRA) of industrial facilities. Given a generic fire scenario, the aim of the methodology was to evaluate the probability of fire damages on industrial equipment both considering the availability and effectiveness of the protective barriers. Fire protections for industrial equipment were first classified, and then literature reliability data were used to build a dataset of Probability of Failure on Demand (PFD) for each protection type. Next, the effectiveness was determined from specific studies and surveys available in the literature. For passive protections, the effectiveness evaluation was based on the protective barrier response to fire. A case study was presented and discussed in order to exemplify the methodology implementation and to show the potential application in simplified QRA studies

Innovative LOPA-based methodology for the safety assessment of chemical plants

The aim of the present work was the development and application of a methodology for the safety assessment of chemical plants based on LOPA (Layer of Protection Analysis) techniques. The approach integrates the use of consolidate hazard identification techniques (HazOp) and the adoption of quantitative literature models for consequence assessment (e.g., integral models) into the LOPA framework, allowing to limit the role played by expert judgment in the evaluation in order to reduce the causes of uncertainty in the results. Furthermore, a systematic and quantitative assessment of safety measures contribution to the reduction of plant residual risk was included in the analysis. In order to apply the methodology, a case study was defined taking into account an actual industrial facility. The results obtained allowed demonstrating the potentialities of the method

Agopuntura comunitaria. Una strategia abitativa per Vila Nova Esperança

I numerosi programmi di slum upgrading in atto nello Stato di São Paulo perseguono l’integrazione socio-spaziale attraverso la rigenerazione delle realtà informali, per far sì che gli abitanti possano avere accesso a beni e servizi primari e raggiungere così, in maniera reale, standard di vita cittadini. Tali interventi sono diversificati: risentono del luogo, della storia della comunità, della sua permanenza nell’area, della presenza o assenza di zone di rischio. Tra le tante strategie percorribili, il nostro contributo intende presentare un’ipotesi di intervento per insediamenti informali. Si tratta di un progetto sperimentale per abitazioni unifamiliari verificato in Vila Nova Esperança, piccola favela ricadente in parte nel Comune di São Paulo e in parte in quello di Taboão da Serra, e per la quale attualmente non sono previsti interventi di rigenerazione. Lo studio, condotto attraverso sopralluoghi e interviste ai favelados, ha consentito una mappatura dell’area, alla luce degli obiettivi della ricerca. Il fine è stato quello di definire un progetto di abitazioni di base minima, la cui realizzazione potesse avvenire in tempo breve, prevedendo al contempo anche un’espansione programmata tanto dell’impianto quanto del sistema-casa. La caratteristica principale della strategia proposta è infatti la volontà di fornire una possibile metodologia di intervento a lungo termine, potenzialmente capace di incidere gradualmente sull’assetto della comunità. L’elaborazione si basa sulla volontà di conservare la ricchezza sociale riscontrata nella comunità, incidendo sulle condizioni di vita e di convivenza attraverso il progetto dell’abitare quale motore per attivare il miglioramento e contribuire allo sviluppo dell’area. Così, partendo da considerazioni urbano-architettoniche ampie ed articolate, si è ragionato sulle modalità di recupero e riconfigurazione degli spazi aperti. Mentre il progetto di architettura, calato nel tessuto consolidato del caso di studio, ha parallelamente previsto la definizione di luoghi a carattere collettivo destinati ad accrescere la coesione comunitaria già riscontrata nella favela

Experimental and numerical characterization of fireproofing materials based on ASTM E162 standard

Fires may affect process and storage equipment causing severe damages and potential accident escalation. Passive protections, based on the application of fireproofing coatings, are usually implemented in order to prevent or mitigate such events. The design and testing of this type of barriers is a critical task due to the extreme heat exposure conditions. For this purpose, several standard tests, based on the use of large scale furnaces and experimental facilities, are adopted. In the present study, a methodology for the assessment of fireproofing materials performance was presented. The methodology was aimed at reducing the costs of fire tests by the combined use of small scale experiments and modeling activities. A novel inorganic formulation based on basalt fibers and silica aerogel was tested and compared with commercial fireproofing materials. A specific Key Performance Indicator (KPI) was evaluated in order to support the effective design of passive fire protections

Frequency evaluation for domino scenarios triggered by heat radiation exposure

Severe fires may damage process equipment or pipes, leading to accident escalation and domino effect. Several accidents that occurred in the chemical and petrochemical industry presented these features. In order to account for these accident scenarios in conventional Quantitative Risk Analysis (QRA) studies, the more critical step is the availability of reliable models to estimate the probability of escalation given the fire impact mode on industrial equipment. The present contribution was aimed at developing a methodological approach to the assessment of the damage probability of process and storage vessels, identified as escalation targets, with the final aim of quantifying the frequency of accidents triggered by domino effect and the implementation in QRA studies. Efforts were devoted to include in the analysis relevant site-specific factors and to consider the presence of eventual mitigation measures. The developed methodology was applied to a case study dealing with the escalation of a primary fire scenario

The performance of inorganic passive fire protections: An experimental and modelling study

The installation of fireproofing materials on equipment and structures is a widely applied and effective solution for the protection of critical process elements against severe fires, in order to prevent possible damages escalation. The choice and design of fireproofing materials is crucial for granting adequate performances. As a matter of fact, properties such as, among others, thermal conductivity and density change substantially when the material is exposed to severe temperatures. In the present study, a methodological approach, integrating experimental and modelling activities, was proposed. Focus was set on a particular class of PFP: inorganic fireproofing materials. A reference set of commercial PFP materials (rock wool, glass wool, silica blanket, etc.) was selected. Small scale experiments allowed determining the variation of the most relevant thermal properties of the coatings and to obtain detailed correlation models for their description. A finite element model (FEM) was developed in order to reproduce the behaviour of real scale equipment exposed to fire and to provide a sound design of the fire protection system

Accident Scenarios Caused by Lightning Impact on Atmospheric Storage Tanks

In recent years, severe natural events raised the concern for the so-called NaTech (natural-technological) accident scenarios: technological accidents caused by the impact of a natural event on an industrial facility or infrastructure. Severe scenarios typical of the process industry, as fires, explosions, toxic releases, and water pollution were reported as the consequence of natural events in industrial areas. The historical analysis of accidental scenarios triggered by lightning shows that the impact of a lightning on an atmospheric storage tank might be the initiating event of a severe accident. The analysis of past accident evidences that several alternative damage mechanisms and accident scenarios may follow lightning impact. Although lightning hazard is well known and is usually considered in the risk analysis of chemical and process plants, well accepted quantitative procedures to assess the contribution of accidents triggered by lightning to industrial risk are still lacking. In particular, the approaches to the assessment of accident scenarios following lightning strike are mostly based on expert judgment. In the present study, a detailed methodology is presented for the assessment of quantified event trees following lightning impact on an atmospheric tank. Different damage mechanisms have been considered in order to assess the frequencies of loss of containment due to lightning strikes. The results were used in a case study to assess the overall risk due to lightning impact scenarios in typical lay-outs of tank farms of oil refineries.JRC.G.6-Security technology assessmen

Accident scenarios caused by lightning impact on atmospheric storage tanks

In recent years, severe natural events raised the concern for the so-called NaTech (natural-technological) accident scenarios: Technological accidents caused by the impact of a natural event on an industrial facility or infrastructure. Severe scenarios typical of the process industry, as fires, explosions, toxic releases, and water pollution were reported as the consequence of natural events in industrial areas. The historical analysis of accidental scenarios triggered by lightning shows that the impact of a lightning on an atmospheric storage tank might be the initiating event of a severe accident. The analysis of past accident evidences that several alternative damage mechanisms and accident scenarios may follow lightning impact. Although lightning hazard is well known and is usually considered in the risk analysis of chemical and process plants, well accepted quantitative procedures to assess the contribution of accidents triggered by lightning to industrial risk are still lacking. In particular, the approaches to the assessment of accident scenarios following lightning strike are mostly based on expert judgment. In the present study, a detailed methodology is presented for the assessment of quantified event trees following lightning impact on an atmospheric tank. Different damage mechanisms have been considered in order to assess the frequencies of loss of containment due to lightning strikes. The results were used in a case study to assess the overall risk due to lightning impact scenarios in typical lay-outs of tank farms of oil refineries. Copyright © 2013, AIDIC Servizi S.r.l

Ren: a novel, developmentally regulated gene that promotes neural cell differentiation

Expansion and fate choice of pluripotent stem cells along the neuroectodermal lineage is regulated by a number of signals, including EGF, retinoic acid, and NGF, which also control the proliferation and differentiation of central nervous system (CNS) and peripheral nervous system (PNS) neural progenitor cells. We report here the identification of a novel gene, REN, upregulated by neurogenic signals (retinoic acid, EGF, and NGF) in pluripotent embryonal stem (ES) cells and neural progenitor cell lines in association with neurotypic differentiation. Consistent with a role in neural promotion, REN overexpression induced neuronal differentiation as well as growth arrest and p27Kip1 expression in CNS and PNS neural progenitor cell lines, and its inhibition impaired retinoic acid induction of neurogenin-1 and NeuroD expression. REN expression is developmentally regulated, initially detected in the neural fold epithelium of the mouse embryo during gastrulation, and subsequently throughout the ventral neural tube, the outer layer of the ventricular encephalic neuroepithelium and in neural crest derivatives including dorsal root ganglia. We propose that REN represents a novel component of the neurogenic signaling cascade induced by retinoic acid, EGF, and NGF, and is both a marker and a regulator of neuronal differentiation