Smoke control in sloping tunnels

Atkinson, Graham T.; Wu, Ying

doi:10.1016/s0379-7112(96)00061-6

Cited by 163 publications

(70 citation statements)

References 2 publications

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“…For many typical road tunnels, the SCVV is found to be about 3 m s -1 , so many emergency ventilation strategies for longitudinally ventilated tunnels aim to achieve a longitudinal flow of about 3 m s -1 in the event of any fire, in order to control smoke. Ventilation studies since 1995 have tended to build on the work of Oka and Atkinson, adding various complexities relating to features such as tunnel slope [6], aspect ratio [7,8] and the presence of blockages [9,10], and the SCVV concept has become widely accepted in the industry.…”

Section: Introductionmentioning

confidence: 99%

Investigating the Throttling Effect in Tunnel Fires

2015

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Abstract. Critical ventilation velocity remains the most studied phenomenon in the tunnel fire literature. But focus on the velocity as the principal parameter may hide other features of the interaction between a fire and tunnel flow. The throttling effect was identified in the 1960s and described in the 1970s, yet it seems to be generally overlooked these days. In essence, the throttling effect is the tendency of a fire in a tunnel to resist the airflow; the larger the fire, the greater the resistance. Thus, while it has been shown that no increase in longitudinal flow velocity is required to control smoke from fires larger than the 'super critical' limit, in practice, an increasing number of ventilation devices are required to achieve this flow, and hence control the smoke from a fire, as the fire size grows. A CFD modelling study using the FDS model has been carried out to demonstrate this effect. It is clearly demonstrated that for fires larger than the 'super critical' limit, an increasing number of jet fans are required to control the smoke from increasingly larger fires. The results of the modelling study are presented.

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Section: Introductionmentioning

confidence: 99%

Investigating the Throttling Effect in Tunnel Fires

2015

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“…Many experimental and numerical studies are carried out to show the quality of the smoke propagation in the tunnel with longitudinal ventilation system [1-8]. The result of such studies confirmed the effect of some key parameters like tunnel geometry, especially longitudinal slope, heat release rate of the fire and air speed, in smoke and temperature distributions [9][10][11][12][13][14][15][16][17][18].…”

Section: Introductionmentioning

confidence: 91%

“…L.Yi et al have conducted a group of fire tests in a model scale to show the effect of the air velocity in the temperature profiles and back-layering over the tunnel length [3]. Atkinson and Wu have performed an experimental study in the model scale to show the critical velocity correlation factor and related temperature profiles in sloping tunnels with range of 0 to 10° [16]. In the other model scale experimental study, Liang Yi et al have investigated the critical velocity correlation factor in sloping tunnels in a range of 0 to ±3% [10].…”

Section: Introductionmentioning

confidence: 99%

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Full Scaled Numerical Simulation of the Critical Velocity in Sloping Tunnels during the High Load Fire Incidents

Rafiei

2015

IJCA

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Fire safety is considered as one of the major objectives in design, construction and specially tunnel operation. The hot and toxic smoke propagation is a fundamental reason of human losses during a fire inside the tunnels. Therefore, an exact analytical investigation on the probable fire scenarios and its destructive effects for passengers, vehicles and structure are the main part of the tunnel safety measures. The complications of tunnel fires can be reduced, using a suitable hot smoke management regime through the standard safety plan.In a unidirectional traffic tunnel, upstream of the fire is usually a place where people and vehicles are trapped and can leave the tunnel during a fire only via egress ways. Meanwhile, downstream the fire people and vehicles in most cases will have a chance to leave the tunnel. In order to have a full view of the problem and to find a proper solution, numerous effective parameters in smoke control and temperature distribution have to be considered in design phases. A sufficient longitudinal air speed is one of the most important parameters in the hot smoke management. Mentioned longitudinal airflow creates a safe place upstream the fire through preventing smoke back-layering from the location of the fire.The critical velocity is known as a required volume flow to prevent smoke back-layering from the location of the fire. The mentioned critical velocity is influenced by the heat release rate (HRR) of the fire, tunnel slope and structural characteristics. The implementation of small size fire tests is an easy and cheap way to see the performance of safety installations, smoke back-layering, and airflow and temperature distributions. However, as in most cases a fullscale fire tests is not easily feasible, CFD simulations can be a great opportunity to investigate the tunnel ventilation in a fire incident.In this numerical study, CFD simulation is employed, to demonstrate the effect of the required critical velocity during the fire with high heat release rates, in a tunnel with different longitudinal slopes. The results are compared with other experimental data and numerical studies.

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“…A wide range of factors were considered, including tunnel slope [64], the use of hydraulic diameter as the characteristic length [65], tunnel aspect ratio [66] and the prediction of critical velocity using CFD analysis [67]. Details of these studies are not included here as they specifically relate to the subject of tunnel fires rather than duct fires; however, Ingason [4,32] presents a good summary of this research.…”

Section: Critical Velocitymentioning

confidence: 99%

Fires in Ducts: A review of the early research which underpins modern tunnel fire safety engineering

Byrne

Georgieva

Carvel

2018

Tunnelling and Underground Space Technology

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Temperature difference due to stratification (K) ∆ Local gas temperature rise (K) ∆ %&'Average gas temperature rise (K) AbstractMuch of the early research which now underpins tunnel fire safety design was carried out experimentally, using small scale ducts. This paper reviews such experiments, mostly carried out in the 1960s, 1970s, and 1980s, highlighting the assumptions and limitations of the early studies, which may have been forgotten as the equations developed have been applied in practice in the subsequent years. The review covers three primary topics; fire propagation under 'turbulent slug flow' conditions, stratification & flame spread, and backlayering & critical ventilation velocity.

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Smoke control in sloping tunnels

Cited by 163 publications

References 2 publications

Investigating the Throttling Effect in Tunnel Fires

Investigating the Throttling Effect in Tunnel Fires

Full Scaled Numerical Simulation of the Critical Velocity in Sloping Tunnels during the High Load Fire Incidents

Fires in Ducts: A review of the early research which underpins modern tunnel fire safety engineering

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