Ventilation effects in confined and mechanically ventilated fires

Lassus, Julie; Courty, Léo; Garo, Jean-Pierre; Studer, Etienne; Jourda, P.; Aine, P.

doi:10.1016/j.ijthermalsci.2013.07.015

Cited by 43 publications

(22 citation statements)

References 9 publications

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“…The powers tested are lower than 130 kW, which corresponds to a maximum HRR of 1 MW at full scale. Details on the derivation of the scaling laws can be found in [15]. Picture and scheme of the experimental setup are presented in Fig.…”

Section: Methodsmentioning

confidence: 99%

“…Inlet duct is located at the bottom of the room test at a 0.3 meter high and extraction network is located near the ceiling, at a 1.7 meter height. The acquisition time is chosen at 6 s. This reduced-scale compartment has already been used in Lassus et al [15] for the investigation of the ventilation effects in confined and mechanically ventilated fires. Let us notice that with this experimental setup air is injected at the bottom of the compartment and the extraction duct is located at the top of the compartment, on the side opposite to the air inlet duct.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Experimental approach to estimate species concentrations in a compartment fire

Lassus¹,

Courty²,

Studer³

et al. 2014

Fire Saf. Sci.

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An approach for estimating species concentration during a fire in a well-stirred compartment is investigated. A semi-empirical model based on oxygen concentration is used. It gives an estimate of the concentrations of carbon monoxide, carbon dioxide, hydrogen and hydrocarbons with a carbon chain length lower than five. Three intervals of oxygen concentration are noticed, they correspond to sufficiently ventilated, underventilated and very underventilated fires. In order to validate this model, fire experiments are performed in a reduced-scale compartment . Species concentrations predicted by the model are in good agreement with our experimental data and with those of literature. Coefficients used for the model are obtained for heptane and dodecane fires.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Experimental approach to estimate species concentrations in a compartment fire

Lassus¹,

Courty²,

Studer³

et al. 2014

Fire Saf. Sci.

Self Cite

View full text Add to dashboard Cite

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“…However, all these experiments were conducted in open atmosphere conditions, and very few studies were performed in confined and mechanically ventilated rooms, such as those found in NPPs. In contrast, many investigations, using hydrocarbon (Pretrel et al, Nasr et al, Melis and Audouin, Lassus et al), alcohol, polymethyl methacrylate (PMMA), or wood (Delichatsios et al) as fuel, were conducted in mechanically ventilated compartments. These fire tests showed a significant influence of the ventilation on both the combustion behaviour and species product formation.…”

Section: Introductionmentioning

confidence: 99%

Cable tray fire tests with halogenated electric cables in a confined and mechanically ventilated facility

2019

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Summary Cable fires are one of the main fire hazards present in nuclear power plants (NPPs). Therefore, as part of the Organisation for Economic Co‐operation and Development (OECD) PRISME‐2 project, cable tray fire tests were performed both in open atmosphere conditions and in a confined and mechanically ventilated facility, called DIVA. These tests aim at showing the effects of a confined and ventilated environment on fire characteristics and consequences. This study deals with five fire tests, which used halogenated (poly [vinyl chloride] or PVC) cable types. Two tests were carried out in open atmosphere and three tests in the DIVA facility. The latter used a ventilation renewal rate (VRR) of either 4 or 15 h−1. The confined and ventilated conditions reduced the mass loss rate and heat release rate than did those obtained in open atmosphere. Furthermore, the three confined tests produced unburnt gases, which ignited in the fire room. Two explosions were highlighted for the tests that used a VRR of 4 h−1. These explosions indeed led to fast flame propagations over the entire upper part of the fire room and steep overpressures of almost 150 hPa. The low‐qualified PVC cables and the ventilation set‐up used in this study strongly contributed to the occurrence of these explosions.

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“…Compared with mechanical ventilation, natural ventilation does not consume electricity and causes less disturbance to the smoke layer stratification, which can be considered as an economic and effective mode . The natural exhausting ventilation mainly uses the buoyancy of the smoke itself, and for natural ventilation shaft, the driving force is the stack effect formed inside the shaft, which is different from the traditional transverse ventilation mode using mechanical smoke extraction vents installed on the tunnel ceiling …”

Section: Introductionmentioning

confidence: 99%

“…Compared with mechanical ventilation, [29][30][31] natural ventilation does not consume electricity and causes less disturbance to the smoke layer stratification, which can be considered as an economic and effective mode. 32,33 The natural exhausting ventilation mainly uses the buoyancy of the smoke itself, and for natural ventilation Nomenclature: A, cross-section area of the shaft (m 2 ); d, smoke layer thickness below smoke vent without smoke exhaust (m); D, longitudinal distance from fire source to shaft (m); D f , transverse distance from fire source to tunnel sidewall (m); D s , transverse distance from shaft to tunnel sidewall (m); F h , horizontal inertia force of the smoke without smoke exhaust (N); F v , vertical buoyancy force of the smoke (N); g, gravitational acceleration (m/s 2 ); h, shaft height (m); v, smoke velocity measured under the smoke vent without smoke exhaust (m/s); w, shaft width (m) Greek letters: ρso, smoke density without smoke exhaust (kg/m 3 ); Δρ, density difference between smoke and ambient air without smoke exhaust (kg/m 3 ) shaft, the driving force is the stack effect [34][35][36] formed inside the shaft, which is different from the traditional transverse ventilation mode using mechanical smoke extraction vents installed on the tunnel ceiling.…”

Section: Introductionmentioning

confidence: 99%

A numerical study on the effects of naturally ventilated shaft and fire locations in urban tunnels

Fan

Chen

Mao³

et al. 2019

Fire and Materials

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Summary In more and more tunnels, natural ventilation mode with vertical shafts has been gradually employed. However, there are few studies investigating the influences of fire and shaft positions on natural ventilation performance currently. Therefore, this study investigated the effects of the transverse distance from fire source to tunnel sidewall, the longitudinal distance from fire source to shaft, and the transverse distance from shaft to sidewall on natural ventilation effectiveness in a tunnel fire by using Fire Dynamics Simulator. The typical characteristic parameters of smoke, such as mass flow rate, temperature distribution, and velocity vector were analyzed; besides, the phenomenon of plug‐holing was discussed. The results have shown that the mass flow rate of gas exhausted by the shaft decreases slightly with the increase of longitudinal distance from fire source to shaft. When the longitudinal distance from fire source to shaft is constant, changing the transverse distance from shaft to sidewall will have a more obvious effect on the effectiveness of exhausting smoke than changing the transverse distance from fire source to sidewall; in addition, the phenomenon of plug‐holing is more serious when the shaft is close to the sidewall.

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Ventilation effects in confined and mechanically ventilated fires

Cited by 43 publications

References 9 publications

Experimental approach to estimate species concentrations in a compartment fire

Experimental approach to estimate species concentrations in a compartment fire

Cable tray fire tests with halogenated electric cables in a confined and mechanically ventilated facility

A numerical study on the effects of naturally ventilated shaft and fire locations in urban tunnels

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