Analysis of a new strategy for emergency ventilation and escape scenario in long railway tunnels in the fire mode

2018 ◽  
Vol 233 (3) ◽  
pp. 239-250 ◽  
Author(s):  
Behtash Hakimzadeh ◽  
Mohammad Reza Talaee
Keyword(s):  
Ventilation System ◽  
Control Panel ◽  
Fire Dynamics ◽  
Railway Tunnel ◽  
Rescue Operation ◽  
Tunnel Ventilation ◽  
Precise Control ◽  
Ventilation Shaft ◽  
Emergency Ventilation ◽  
Safe Path

The creation of a safe path for evacuating passengers from a tunnel during fire accidents is an important function of a mechanical ventilation system in tunnels. In this work, the operation of emergency ventilation in the fire mode in a long railway tunnel with push–pull ventilation shafts is analyzed using a fire dynamics simulator. As the passenger trains are lengthy – and so is a tunnel – when trains pass through a tunnel, the position of fire on the train becomes an important parameter for rescuing the passengers through a safe path. The novelty of this study is in the design of emergency ventilation scenarios that consider the position of fire on the train in addition to the tunnel ventilation shafts. For this case study, a lengthy (8 km) urban railway tunnel in Tehran with four rail tracks and eight ventilation shafts is considered for designing emergency ventilation scenarios and control of fire products. The fire source is a passenger train wagon with a 25-MW heat release rate. It is shown that, during the rescue operation of the passengers, the location of fire on the train may lead to reverse the ventilation scenario compared with the traditional ones that use only the tunnel shafts. Also, it is observed that there is a region with 50 m radius around each ventilation shaft, i.e. the absolute exhaust zone, where the ventilation system must be set at the exhaust mode due to the presence of fire, to minimize the spreading of fire products downstream. All the logical scenarios of the tunnel ventilation system are designed and demonstrated to create a critical ventilation velocity in the tunnel, which would help in developing a more precise control panel of the tunnel in the fire mode.

A New Advance in Tunnel Ventilation Design Planning

2017 ◽  
Author(s):  
Mark P. Colino ◽  
Elena B. Rosenstein
Keyword(s):  
Ventilation System ◽  
National Fire Protection Association ◽  
Capital Cost ◽  
Smooth Transition ◽  
Mechanical Equipment ◽  
Tunnel Ventilation ◽  
Tunnel Fire ◽  
Ventilation Shaft ◽  
Emergency Ventilation ◽  
Ventilation Fan

The new train signaling, traction power and tunnel ventilation system coordination guidelines enacted in National Fire Protection Association (NFPA) Standard 130 have brought the necessity and cost of tunnel ventilation fan shafts into greater focus. The guidelines were aimed at coordinating the three aforementioned rail systems to control the number of trains that could be between successive ventilation shafts during an emergency — in recognition of the fact that the best protection to both incident and non-incident train passengers and crew is to allow no more than one train in each ventilation zone. Though based in safety, these new NFPA guidelines can substantially expand the capital cost and environmental impact of new rail tunnel projects by adding more ventilation shafts and tunnel fan equipment to the scope of work. In addition, the resulting increase in the required number of ventilation shafts and tunnel fan equipment can hinder existing railroad properties as they seek to either increase their train throughput rates, or reduce their tunnel electrical infrastructure. Fortunately, a new kind of emergency ventilation shaft has been developed to facilitate compliance with the NFPA 130 Standard without the excessive capital cost and far-reaching environmental impacts of a traditional emergency ventilation shaft. This new kind of emergency ventilation shaft is called the Crossflue. The Crossflue is a horizontal passage between parallel rail tunnels with a single ventilation fan-motor unit installation. The Crossflue fan is designed to transfer air/smoke flows from one (occupied, incident) tunnel to another (unoccupied, non-incident) tunnel — thereby protecting the incident tunnel at the expense of the non-incident tunnel. The Crossflue passage has angled construction to allow a smooth transition of airflows both into and out of the adjoining tunnels. In addition to the fan, the Crossflue contains a ventilation damper, sound attenuators, ductwork transitions and flexible connectors within the fan equipment line-up; the functionality of all this mechanical equipment is described in the paper. To preserve underground space and minimize the rock excavation, the Crossflue fan is both remotely-powered and remotely-controlled; the fan is only operated as part of a pre-programmed response to tunnel fire events. The methodology utilized to design the Crossflue was taken from the Subway Environmental Design Handbook (SEDH); the SEDH [1] was specifically developed for rail tunnel ventilation design and is the preeminent reference volume in the industry. In summary, the Crossflue provides a dual benefit of achieving NFPA 130 compliance, while at the same time minimizing the construction, equipment, environmental, and energy costs of a traditional tunnel ventilation shaft.

A Study on Optimization of Middle Vent Shaft in Subway Tunnel Ventilation System

2013 ◽  
Vol 838-841 ◽  
pp. 1381-1386
Author(s):  
Fang Lin ◽  
Yan Hua Zeng ◽  
Xiao Han Zhou ◽  
Jian Feng He
Keyword(s):  
Simulation Analysis ◽  
Geometric Model ◽  
Ventilation System ◽  
Subway Tunnel ◽  
Railway Tunnel ◽  
Tunnel Ventilation ◽  
Advantages And Disadvantages ◽  
Transportation Capacity ◽  
Design Documents ◽  
Wall Surface Temperature

The air flow and temperature variation in the subway tunnel are different in the railway tunnel. Its necessary to study the middle vent shaft in subway tunnel ventilation system. According to the primary design documents of one subway line in Chengdu, the paper sets up the metros geometric model which is used in the SES program and also does the simulation analysis of the biggest transportation capacity in the line. The simulation mainly analyzes the adoption of the middle vent shaft which is located in the running tunnel between the station A and B. Meanwhile it also analyzes the influence of middle vent shaft on the nearby piston vent shaft, the wall surface temperature and the air temperature in the tunnel. Finally it takes temperature as the estimated index, analyzes the advantages and disadvantages of the middle vent shaft and makes the theoretic accounts for the design. The comprehensive analysis is that this middle vent shaft could be canceled.

One Train per Ventilation Zone: Application and Innovation

2010 ◽  
Author(s):  
Mark P. Colino ◽  
Elena B. Rosenstein
Keyword(s):  
Ventilation System ◽  
National Fire Protection Association ◽  
Plant Design ◽  
Construction Costs ◽  
Tunnel Ventilation ◽  
Existing Structures ◽  
Passenger Rail ◽  
Ventilation Shaft ◽  
Design Coordination ◽  
Traction Power

In recognition of paragraph 7.2.5 of the National Fire Protection Association (NFPA) Standard 130 for Fixed Guideway and Passenger Rail Systems, a major commuter railroad project design team has undertaken detailed coordination of its train signaling, traction power and tunnel ventilation systems. Per the writing of the Standard, the coordination effort was aimed at designing the systems to match the total number of trains that could be between ventilation shafts during an emergency, but also recognized that, the best protection to passengers is to allow no more than one train in a ventilation zone. The coordination of the train signaling, traction power and tunnel ventilation system designs per NFPA 130 paragraphs 7.2.5 and A.7.2.5 has permitted the project to achieve a reasonable degree of safety from fire and its related hazards, while at the same time: preserving the commuter railroad’s throughput requirements; reducing overall construction costs; and, minimizing civic/environmental impacts. In particular, the design coordination has permitted the project to forego tunnel fan installations within existing structures in one portion of the project, and an innovative fan plant design between two tunnels has precluded the need for an additional tunnel ventilation shaft in another portion of the project.

scholarly journals Fire safety case study of a railway tunnel: Smoke evacuation

2007 ◽  
Vol 11 (2) ◽  
pp. 207-222 ◽  
Author(s):  
Maele van ◽  
Bart Merci
Keyword(s):  
Fire Safety ◽  
Large Scale ◽  
Natural Ventilation ◽  
Real Life ◽  
Test Case ◽  
Fire Dynamics ◽  
Railway Tunnel ◽  
Tunnel Section ◽  
Safety Case ◽  
Smoke Evacuation

When a fire occurs in a tunnel, it is of great importance to assure the safety of the occupants of the tunnel. This is achieved by creating smoke-free spaces in the tunnel through control of the smoke gases. In this paper, results are presented of a study concerning the fire safety in a real scale railway tunnel test case. Numerical simulations are performed in order to examine the possibility of natural ventilation of smoke in inclined tunnels. Several aspects are taken into account: the length of the simulated tunnel section, the slope of the tunnel and the possible effects of external wind at one portal of the tunnel. The Fire Dynamics Simulator of the National Institute of Standards and Technology, USA, is applied to perform the simulations. The simulations show that for the local behavior of the smoke during the early stages of the fire, the slope of the tunnel is of little importance. Secondly, the results show that external wind and/or pressure conditions have a large effect on the smoke gases inside the tunnel. Finally, some idea for the value of the critical ventilation velocity is given. The study also shows that computational fluid dynamics calculations are a valuable tool for large scale, real life complex fire cases. .

scholarly journals Numerical Study of Smoke Propagation in a Simulated Fire in a Wagon Within a Subway Tunnel

2008 ◽  
Author(s):  
Felipe Vittori ◽  
Luis Rojas-Solo´rzano ◽  
Armando J. Blanco ◽  
Rafael Urbina
Keyword(s):  
Numerical Study ◽  
Ventilation System ◽  
Road Tunnel ◽  
Subway Tunnel ◽  
Longitudinal Ventilation ◽  
Emergency Ventilation ◽  
Tunnel Section ◽  
Fire Scenarios ◽  
Subway Stations ◽  
Set Up

This work deals with the numerical (CFD) analysis of the smoke propagation during fires within closed environments. It is evaluated the capacity of the emergency ventilation system in controlling the smoke propagation and minimizing the deadly impact of an eventual fire in a wagon within the Metro de Caracas subway tunnel on the passengers safety. For the study, it was chosen the tunnel section between Teatros and Nuevo Circo subway stations, which consists of two parallel independent twin tunnels, connected through a transverse passage. The tunnels are provided by a longitudinal ventilation system, integrated by a set of reversible fans located at both ends of the tunnels. Three stages were considered in the study: (a) Model set up; (b) Mesh sensitivity analysis; (c) Validation of the physical-numerical parameters to be used in the numerical model; and (d) Simulation of fire scenarios in Metro de Caracas subway stations. Stages (b)–(c), aimed to testing and calibrating the CFD tool (ANSYS-CFX10™), focused on reproducing experimental data from Vauquelin and Me´gret [1], who studied the smoke propagation in a fire within a 1:20 scale road tunnel. Stage (d) critical scenarios were established via a preliminary discussion with safety experts from Metro de Caracas, in order to reduce the computer memory and the number of simulations to be performed. The analyses assessed the reliability of escape routes and alternative paths for the evacuation of passengers. Additionally, the smoke front movement was particularly computed, as a function of time, in order to determine the possible presence of the “backlayering” phenomenon [5]. Results demonstrate the strengths and weaknesses of the current ventilation system in the event of a fire in the subway tunnel, and suggest new strategies to address this potentially lethal event to minimize the risks for passengers.

Underground Research Laboratories in Japan: What Are the Important Factors for Facilities Design?

2003 ◽  
Author(s):  
T. Sato ◽  
S. Mikake ◽  
M. Sakamaki ◽  
K. Aoki ◽  
S. Yamasaki ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
Sedimentary Rock ◽  
Mechanical Stability ◽  
Ventilation System ◽  
Sedimentary Rocks ◽  
Crystalline Rock ◽  
Ventilation Network ◽  
Main Stage ◽  
Middle Stage ◽  
Ventilation Shaft

This paper describes the current status of two Japanese off-site Underground Research Laboratories (URLs) Projects, one for crystalline rock and the other for sedimentary rock. This paper is focused on mechanical stability and ventilation, important factors relevant to the design and construction of deep underground facilities. High-pressure inflow, another important factor, will be included in the URL project for crystalline rock. The site of the URL project for crystalline rock is located in Mizunami, Gifu, in the central part of the main island of Japan. The regional geology consists of the Tertiary and Quaternary sedimentary rocks overlying Cretaceous granitic basement. Surface-based investigations, including geological mapping, a seismic refraction survey and shallow borehole investigations, and site preparation at the MIU (Mizunami Underground Research Laboratory) Project site have started in 2002. Numerical analysis is carried out to understand mechanical stability around the openings. The ventilation system design is based on numerical analysis using a ventilation network model. Grouting against the high-pressure inflow is planned. Conceptual design for the MIU at present is as follows: • Two 1,000 m shafts, a Main Shaft (6.5m φ) and a Ventilation shaft (4.5m φ); • Two experimental levels, the Main Stage at 1,000 m and the Middle Stage, at 500 m depths. The site of the URL project for sedimentary rock is located in Horonobe, Hokkaido, north of the main island of Japan. The geology consists of Tertiary sedimentary rocks. Surface-based investigation phase started in 2001. Numerical analysis is carried out to understand mechanical stability of the openings, and to design support. The numerical analysis using ventilation network model is carried out to design the ventilation system and disaster prevention method. Conceptual design for the Hnb-URL at present is as follows: • Two 500 m shafts and a Ventilation shaft; • Two experimental levels, the Main Stage at 500 m and the Middle Stage at 250 m depths.

Sign in / Sign up

Export Citation Format

Share Document