8. Use of tunnel ventilation for fire safety

Jagger, Stuart; Grant, George

doi:10.1680/hotfs.31685.0008

Cited by 4 publications

(4 citation statements)

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“…Oka et al [54] and Kuwana et al [55] have examined the variation of flame length and tilt for flames which did not reach to the ceiling. They obtained a similar dependence on ventilation rate although the dependence on heat release rate was somewhat weaker [56]. Lönnermark and Ingason [39] developed a flame length correlation based on a combination of a plume flow correlation and equation (7):…”

Section: Flame Lengthmentioning

confidence: 93%

State of the Art of Tunnel Fire Research

Ingason¹

2008

Fire Saf. Sci.

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This paper gives an overview of the tunnel fire research, both experimental and theoretical work with the exception of computer modelling. The overview shows that the critical velocity for longitudinal flow in a tunnel is the single most well investigated fire phenomenon found in the tunnel fire research literature. This knowledge has reached a high level but there are still some areas that need to be investigated further. For example, very little work has been done on backlayering of smoke upstream a fire and cross-sectional effects on heat release rates, temperatures, flame lengths, fire spread and toxic conditions. Extensive work using model scale tunnels has contributed with new information and clarified many phenomena but the lack of good large scale experimental data is and will be a key issue in near future. This concerns mainly the correlation between heat release rate and maximum ceiling temperatures, the influence of ventilation on maximum heat release rate and fire growth rate and fire spread in and between vehicles. The extensive theoretical work which has been conducted concerning the effects of ventilation on heat release rates needs to be further investigated in large scale tests.* Q dimensionless heat release rate 0 ambient conditions

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Section: Flame Lengthmentioning

confidence: 93%

State of the Art of Tunnel Fire Research

Ingason¹

2008

Fire Saf. Sci.

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“…Dua zmienno prdkoci przepływu powietrza oraz kierunku jest zjawiskiem szczególnie niepodanym. Moe ona powodowa zaburzenie zakładanego rozdziału warstwy dymu od warstwy chłodnego powietrza [1], [2] , [3], co w konsekwencji moe powoda nieskuteczne odprowadzanie dymu i ciepła z tunelu.…”

Section: System Wentylacji Naturalnej Tuneli Drogowychunclassified

Wind influence on the flow inside the road tunnels in the case of the fire

Sztarbała

2013

Bud-Arch

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An important factor in ensuring the fire safety of a construction works, such as a tunnel, is the effective evacuation of smoke and heat to allow people to evacuate and enable to fight a fire. In short tunnels natural ventilation is used, where the flow of air is caused by natural convection phenomena and weather conditions. The results of this research show that the stratification phenomenon in naturally ventilated tunnels occurs in windless conditions only. Flow blockage was observed for a wind angle equal to 90°, causing smoke and heat to remain in the tunnel. The use of natural ventilation to remove smoke and heat from short tunnels is inappropriate due to the ineffective functioning, in the case of the fire and wind action.

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“…Ventilation system helps in controlling smoke in case of fire inside tunnel. There are three commonly employed ventilation systems for tunnels, namely longitudinal, transverse, and semi-transverse systems (Jagger and Grant 2005). The longitudinal ventilation system creates a longitudinal flow of air along the length of the tunnel by introducing or removing air from the tunnel at a limited number of points.…”

Section: Introductionmentioning

confidence: 99%

“…The ability of the longitudinal ventilation system to prevent back layering is a measure of the adequacy of the ventilation system for smoke control. The minimum air velocity necessary to prevent back layering of smoke over the stalled vehicle is known as the critical velocity (Danziger and Kennedy 1982;Jagger and Grant, 2005). The critical velocity depends on the fire heat release rate (fire size), the slope, and the tunnel section geometry.…”

Section: Introductionmentioning

confidence: 99%

Numerical studies on evaluation of smoke control system of underground metro rail transport system in India having jet injection system: A case study

2011

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The rail based urban transport system is being developed for national capital of India, New Delhi. The smoke control using ventilation in case of fire inside the tunnel, similar to Delhi Metro corridor has been investigated using computational fluid dynamics technique. A section of tunnel having dimensions 400 m long, 5.5 m wide and 6 m high is considered for simulation. The analysis has been carried out by assuming a variable fire source with a peak heat release rate (HRR) of 16 MW, located at the center of the tunnel. Ventilation ducts are located in the ceiling near the tunnel portals and are inclined at 10 degrees to the plane of the ceiling through which fans discharge air. The influence of the fire HRR curve slope on the smoke flow dynamics in a realistic tunnel model fitted with jet injection type longitudinal ventilation system has been investigated. In case of fire two cases are studied: (1) fans activated immediately after detection, (2) fans activated at delayed times to take into account the response time for the fans to achieve its maximum speed. The velocity of supply and exhaust fans necessary to remove smoke in 30 s from the upstream direction is determined. The velocities of fan required to produce desired critical velocity in the longitudinal direction for different HRR of fire is predicted. Keywordstunnel fires, computational fluid dynamics, ventilation, inclined ducts Article History

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8. Use of tunnel ventilation for fire safety

Cited by 4 publications

References 0 publications

State of the Art of Tunnel Fire Research

State of the Art of Tunnel Fire Research

Wind influence on the flow inside the road tunnels in the case of the fire

Numerical studies on evaluation of smoke control system of underground metro rail transport system in India having jet injection system: A case study

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