In recent years, many large cities in Italy and the world have created a subway transport system to deal with the increasingly frequent problems due to road congestion, taking advantage of the unused spaces in the subsoil. However, precisely because of the location of the system and the complexity of the work and the high number of people who may be present, the underground has proved to be an environment in which even very serious consequences can occur in the event of a fire. This thesis work was created in collaboration with METRO BLU SCA RL, an organization that deals with the design and construction of the new Milan M4 underground line, with the aim of studying the fire case of a metropolitan train that has arrested within the tunnel segment between two stations, and to analyze the method of exodus of passengers. The thesis was carried out in light of the dictates of the Fire Safety Engineering (FSE) which, by introducing the performance (or engineering) approach, makes it possible to tackle the problems of fire safety according to innovative methodologies, especially with respect to the national planning and regulatory framework. In the first part of the work, after briefly describing the characteristics of the M4 line, the subject of the thesis is framed. Initially, a reference was made to the evolutionary state of the “driverless” technology of metropolitan transport systems, to continue by listing the significant incidents related to fire events inside a subway. Immediately afterwards, the national regulatory references of the sector and the basic principles of fire prevention on the underground were presented. Finally, the main sources on which the current knowledge of fire safety is based are presented: large-scale experimental simulations and those with computational models. Subsequently the key principles are introduced to master the theme of fire, phenomenology, chemistry and the physics of combustion. We then move on to discuss fluid dynamics and the laws that describe it and that are at the base of the equations governing computational fluid dynamics models. Among these, the FDS software is presented in detail, which was implemented in this thesis work to solve a fire simulation. In the second part of the work it is accurately described how FDS was used to model the expected fire scenario, which were the major problems faced and how they were overcome. The adoption of a software to simulate the fire object of the study allowed me to investigate the most influential parameters for the determination of the maximum permissible time of permanence in the tunnel for users without these being in unacceptable living conditions (ASET). Finally, the other software used during this thesis work, Pathfinder, was described in the following chapter. This modeling program allows to simulate the characteristics of the exodus of the people towards a safe place and was used to analyze the behavior assumed by the passengers during the emergency. The output of this type of simulation was the time required to complete the evacuation from the tunnel (RSET). To conclude, the parameters of ASET and RSET were compared, according to the principles of the Fire Safety Engineering, and the results obtained were discussed.
Negli ultimi anni molte grandi città in Italia e nel mondo hanno realizzato un sistema di trasporto metropolitano per poter affrontare le problematiche, sempre più frequenti, dovute alla congestione stradale, sfruttando gli spazi inutilizzati nel sottosuolo. Tuttavia, proprio per la particolare sede del sistema unitamente alla complessità dell’opera e all’elevato numero di persone che vi possono essere presenti, la metropolitana si è dimostrata essere un ambiente in cui si possono verificare conseguenze anche molto gravi in caso d’incendio. Il presente lavoro di tesi nasce in collaborazione con METRO BLU S.C.A R.L., ente che si occupa della progettazione e della realizzazione della nuova linea della Metropolitana di Milano M4, con l’intento di studiare il caso d’incendio di un treno metropolitano che si è arrestato all’interno del segmento di galleria tra due stazioni, e di analizzare la metodologia d’esodo dei passeggeri. La tesi è stata realizzata alla luce dei dettami della Fire Safety Engineering (FSE) che, introducendo l’approccio prestazionale (o ingegneristico), permette di affrontare le problematiche della sicurezza antincendio secondo delle metodologie innovative, soprattutto rispetto al panorama progettuale e normativo nazionale. Nella prima parte del lavoro, dopo aver descritto brevemente le caratteristiche della linea M4, viene inquadrato l’argomento oggetto della tesi. Inizialmente è stato fatto un accenno allo stato evolutivo della tecnologia “driverless” dei sistemi di trasporto metropolitani, per proseguire elencando gli incidenti significativi connessi ad eventi d’incendio all’interno di una metropolitana. Subito dopo sono stati presentati i riferimenti normativi di settore a livello nazionale ed i principi base della prevenzione incendi in metropolitana. Infine, sono state esposte le principali fonti su cui si basa l’attuale conoscenza in merito alla sicurezza antincendio: le simulazioni sperimentali su larga scala e quelle con modelli computazionali. Successivamente vengono introdotti i principi chiave per padroneggiare la tematica dell’incendio, la fenomenologia, la chimica e la fisica della combustione. Si passa poi a discutere di fluidodinamica e delle leggi che la descrivono e che sono alla base delle equazioni governanti i modelli fluidodinamici computazionali. Tra questi viene presentato in dettaglio il software FDS, che è stato implementato in questo lavoto di tesi per risolvere una simulazione d’incendio. Nella seconda parte del lavoro si descrive accuratamente come è stato impiegato FDS per modellare lo scenario d’incendio previsto, quali sono stati i maggiori problemi affrontati e come sono stati superati. L’adozione di un software per simulare l’incendio oggetto dello studio mi ha permesso di indagare i parametri più influenti per la determinazione del tempo massimo ammissibile di permanenza nella galleria per gli utenti senza che questi si trovino in condizioni di vivibilità non accettabili (ASET). Infine, nel capito successivo è stato descritto l’altro software utilizzato durante questo lavoro di tesi, Pathfinder. Questo programma di modellazione permette di simulare le caratteristiche dell’esodo delle persone verso un luogo sicuro ed è stato impiegato per analizzare il comportamento assunto dai passeggeri durante l’emergenza. Il dato di output di questo tipo di simulazioni è stato il tempo necessario per completare l’evacuazione dalla galleria (RSET). Per concludere sono stati confrontati i parametri di ASET e RSET, secondo i principi della Fire Safety Engineering, e sono stati discussi i risultati ottenuti.
Incendio ed esodo in una galleria per metropolitane a funzionamento automatico
BROGIOLI, CARLO ALBERTO
2017/2018
Abstract
In recent years, many large cities in Italy and the world have created a subway transport system to deal with the increasingly frequent problems due to road congestion, taking advantage of the unused spaces in the subsoil. However, precisely because of the location of the system and the complexity of the work and the high number of people who may be present, the underground has proved to be an environment in which even very serious consequences can occur in the event of a fire. This thesis work was created in collaboration with METRO BLU SCA RL, an organization that deals with the design and construction of the new Milan M4 underground line, with the aim of studying the fire case of a metropolitan train that has arrested within the tunnel segment between two stations, and to analyze the method of exodus of passengers. The thesis was carried out in light of the dictates of the Fire Safety Engineering (FSE) which, by introducing the performance (or engineering) approach, makes it possible to tackle the problems of fire safety according to innovative methodologies, especially with respect to the national planning and regulatory framework. In the first part of the work, after briefly describing the characteristics of the M4 line, the subject of the thesis is framed. Initially, a reference was made to the evolutionary state of the “driverless” technology of metropolitan transport systems, to continue by listing the significant incidents related to fire events inside a subway. Immediately afterwards, the national regulatory references of the sector and the basic principles of fire prevention on the underground were presented. Finally, the main sources on which the current knowledge of fire safety is based are presented: large-scale experimental simulations and those with computational models. Subsequently the key principles are introduced to master the theme of fire, phenomenology, chemistry and the physics of combustion. We then move on to discuss fluid dynamics and the laws that describe it and that are at the base of the equations governing computational fluid dynamics models. Among these, the FDS software is presented in detail, which was implemented in this thesis work to solve a fire simulation. In the second part of the work it is accurately described how FDS was used to model the expected fire scenario, which were the major problems faced and how they were overcome. The adoption of a software to simulate the fire object of the study allowed me to investigate the most influential parameters for the determination of the maximum permissible time of permanence in the tunnel for users without these being in unacceptable living conditions (ASET). Finally, the other software used during this thesis work, Pathfinder, was described in the following chapter. This modeling program allows to simulate the characteristics of the exodus of the people towards a safe place and was used to analyze the behavior assumed by the passengers during the emergency. The output of this type of simulation was the time required to complete the evacuation from the tunnel (RSET). To conclude, the parameters of ASET and RSET were compared, according to the principles of the Fire Safety Engineering, and the results obtained were discussed.File | Dimensione | Formato | |
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https://hdl.handle.net/10589/146423