Critical Velocity and Backlayering Conditions in Rail Tunnel Fires: State-of-the-Art Review

Haddad, Razieh Khaksari; Maluk, Cristián; Reda, E.; Harun, Zambri

doi:10.1155/2019/3510245

Cited by 17 publications

(12 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These temperatures are approximately 25% higher than the peak temperatures recorded during fire tests in the Runehamar Tunnel (whose cross-section has similar dimensions as Tunnel 2) in Norway for a 200 MW fire (21). It is important to note that the Runehamar 200 MW fire test included forced ventilation at critical velocity, which it commonly implemented to mitigate the effects of fire in tunnels (22) and can decrease the maximum recorded temperature due to increased longitudinal air flow (23).…”

Section: Fire Characterizationmentioning

confidence: 89%

Vulnerability of Drop Ceilings in Roadway Tunnels to Fire-Induced Damage

Ouyang

Guo

Quiel

et al. 2021

Transportation Research Record: Journal of the Transportation R

View full text Add to dashboard Cite

Roadway tunnels often include a reinforced concrete drop ceiling that is hung from the liner to create a plenum that facilitates ventilation and houses utilities. Drop ceiling panels are lightweight compared with the much thicker tunnel liner and can experience significant damage from a fire on the roadway below. This paper examines the flexural response of drop ceiling panels in two representative tunnels to standard fire curves as well as several realistic fires due to vehicular accidents. Standard fire demands as per the Rijkswaterstaat and ASTM E1529 fire curves are uniformly applied to the ceiling panels, and heat exposure contours for typical vehicle fires with heat release rates of 30, 100, and 200 MW are generated from the software CFAST. The finite element analysis software SAFIR is used to evaluate the thermo-mechanical behavior of the ceiling panels when subjected to various thermal demands from the fire below. The analysis results indicate that drop ceiling panels are highly vulnerable to fire-induced damage and potential collapse both during a fire’s active heating phase (from simultaneous loss of capacity and restraint of thermal expansion) and during the subsequent cooling period (from tension that develops when the permanently deformed panel thermally retracts). The potential for fire-induced damage or collapse of the drop ceiling panels can be mitigated by reducing the fire hazard, removing the drop ceiling, or enhancing the fire resistance of the panels via the application of passive protection or structural hardening.

show abstract

Section: Fire Characterizationmentioning

confidence: 89%

Vulnerability of Drop Ceilings in Roadway Tunnels to Fire-Induced Damage

Ouyang

Guo

Quiel

et al. 2021

Transportation Research Record: Journal of the Transportation R

View full text Add to dashboard Cite

show abstract

“…Many researchers have developed models for quantifying smoke characteristics under the ceiling in case of a tunnel fire (Yan et al 2009;Li et al 2011;Li et al 2012a;Ji et al 2011). Research related to smoke properties, which focused on experimental and theoretical research, was reviewed by Haddad et al (2019). However, most studies have aimed at addressing situations in which the burner is located at the origin of the tunnel; a few studies have considered the contexts of different longitudinal fire source locations.…”

Section: Discussion On Analyzed Models and Experimentsmentioning

confidence: 99%

Experimental Investigation on the Influences of Different Horizontal Fire Locations on Smoke Temperature Stratification under Tunnel Ceiling

Haddad¹,

Zulkifli²,

Maluk³

et al. 2020

JAFM

View full text Add to dashboard Cite

The increased probability of fire occurrence in urban tunnels has led researchers to investigate this issue extensively. Although fire can occur at any point in a tunnel, the effect of fire source position on temperature distribution has not received considerable attention in most of previous investigations. In this research, the influences of varying horizontal fire source locations on temperature diffusion in particular maximum smoke temperature stratification beneath the ceiling has been investigated. A set of scale-down experiments was performed in a model tunnel [3 m (length) × 0.6 m (width) × 0.96 m (height)]. n-Heptane and gasoline were used as fuels in rectangular pools to generate a heat source. The analysis reveals that typical temperature curves have a similar trend when the fire source location changes. Furthermore, the temperature profile tip (maximum smoke temperature) is located between the burner and the origin of the tunnel. The modified model of maximum temperature, which considers the horizontal fire source location, is defined. The results here complement existing literature where the effects of variable fire position in a tunnel have not been considered.

show abstract

“…Additionally, many scholars [22][23][24][25][26][27][28] have studied the influence of blockage on the smoke back-layering length. Haddad et al [29] reviews recent research advances relating to critical velocity and the back-layering length of tunnel fires, mainly analyzing the experimental and theoretical studies on the effects of blockage, inclination, and fire source location. Chaabat et al [30] studied the effect of solid barriers and blockages on the length of smoke back-layering and critical velocity for a fire in a longitudinally ventilated tunnel.…”

Section: Hmentioning

confidence: 99%

“…Table 3 lists the result of dimensionless smoke back-layering length in the simulation cases. Based on the theoretical analysis of Section 3.2.2, by combining Equations ( 18), (19), and (29), it is obtained:…”

Section: Smoke Is Restricted To the Length Of The Metro Trainmentioning

confidence: 99%

Effect of the Metro Train on the Smoke Back-Layering Length under Different Tunnel Cross-Sections

et al. 2022

View full text Add to dashboard Cite

Smoke back-layering length is an important aspect of tunnel fire research, and the influence of metro train blockage cannot be ignored. In previous studies, less attention has been paid to the phenomenon of back-layering caused by the same train blocked in tunnels with different cross-sections. This paper investigates this point through dimensionless analysis and fire dynamic simulator (FDS) numerical simulation. Several full-scale model tunnels (300 m in length), with different tunnel cross-sections, were constructed in FDS. According to the FDS simulation result, the smoke back-layering length was compared and analyzed. To investigate the effect of the tunnel cross-sections on smoke back-layering length under metro train blocking, the headroom ratio ε was proposed. Then, the influence of the tunnel cross-section on the smoke back-layering length was discussed in detail. Based on the dimensional analysis and FDS simulation results, a new model for predicting the smoke back-layering length was proposed. The prediction model obtained in this paper was compared with the FDS simulation results and the prediction model proposed by our predecessors. It is proven that the proposed model can better predict the length of smoke back-layering when metro trains are blocked in tunnels with different cross-sections. The outcomes of this work are expected to provide theoretical guidance for fire smoke control in metro tunnels with different cross-sections.

show abstract

Critical Velocity and Backlayering Conditions in Rail Tunnel Fires: State-of-the-Art Review

Cited by 17 publications

References 45 publications

Vulnerability of Drop Ceilings in Roadway Tunnels to Fire-Induced Damage

Vulnerability of Drop Ceilings in Roadway Tunnels to Fire-Induced Damage

Experimental Investigation on the Influences of Different Horizontal Fire Locations on Smoke Temperature Stratification under Tunnel Ceiling

Effect of the Metro Train on the Smoke Back-Layering Length under Different Tunnel Cross-Sections

Contact Info

Product

Resources

About