Basic theory you should know about tunnel fire evacuation

With the vigorous development of China's transportation infrastructure, the number of tunnels is increasing and the length is getting longer.

In order to protect the safety of tunnels, the fire and disaster relief is all the more important.

I. Study on the law of smoke flow in tunnel fires

Unlike general buildings, tunnel vents are relatively small. In the event of a fire accident, the fumes from the fire are difficult to eliminate. In recent years, a series of tunnel fire accidents at home and abroad have shown that most people are poisoned by smoke.

A large number of scholars at home and abroad have carried out extensive research on the spread and development of tunnel fire smoke, which has provided some help for revealing the development law of tunnel fire smoke and controlling fire smoke.

Aiming at the research on the flow law of tunnel fire smoke, many foreign scholars such as CarvelR, ThomasP, IngasonH, etc. have carried out a lot of research through simulation and experimental means, and have achieved many results.

In China, research on tunnel fire smoke has gradually increased in recent years. Hu Longhua et al. studied the influence of different layouts of air inlets on the efficiency of exhaust ventilation in underground tunnels, and proposed optimization suggestions for tunnel exhaust systems. Zhang Peng et al. used CFD numerical software to simulate the fire of tunnel buildings and revealed the tunnel. The characteristics of internal smoke movement and fire spread under different combustion conditions; Xu Qinkun found in the study that when the tunnel fire develops to the flashback stage after a certain period of time, the fire smoke will pulsate, so that the smoke will reciprocate in the narrow tunnel. motion.

The research of these scholars has laid a certain theoretical foundation for the fire spread of tunnel fires, and also provided theoretical support for fire fighting and rescue and smoke control of tunnels.

Table 6.1 summarizes some domestic and foreign scholars' research on the smoke flow law of tunnel fires.

Table 6.1 Study on the law of tunnel fire

Second, the tunnel fire way

As various types of tunnels increase year by year, equipment becomes more and more complicated, and there are more and more factors that cause fires, and tunnel fire accidents occur frequently.

Table 6.2 lists several tunnel fires and their methods of smoke extraction in the country since 2009.

Table 6.2 Tunnel fire case

In the case of several fires listed in Table 6.2, the effect of smoke from the fire was not ideal.

The internal space of the tunnel makes the natural smoke exhaust slow, and the mechanical exhaust of the fixed system cannot meet the demand.

In addition to the fixed system using a mobile firefighting team exhaust equipment, a smoke tunnel by way of positive pressure air supply, exhaust is another effective way. Strengthening the fire and air exhaust of mobile equipment has become an inevitable demand for tunnel fire smoke control.

Third, the fixed smoke exhaust facilities are difficult to meet the smoke demand of the fire

The tunnel fires the smoke, mainly relying on natural smoke and fixed smoke. However, when a fire occurs, once the temperature of the fire smoke is too high, the fixed mechanical smoke exhausting facilities such as the exhaust fan and the jet fan installed in the tunnel may not operate effectively due to the high temperature.

At this time, the fixed smoke exhaust system cannot meet the smoke control under fire conditions, and is extremely disadvantageous for evacuation of personnel and fire fighting.

Fourth, the development of mobile smoke

Based on the positive pressure Ventilation Theory (Positive Pressure Ventilation) has been widely used abroad, and domestic research on the exhaust of mobile fans has begun.

Ministry of Public Security Fire Department issued in August 2013 under the "fire water investigation and protection equipment smoke actual testing manual", emphasized the important role played by mobile exhaust equipment in fire fighting and fire brigade specially equipped for all kinds of Fans have been tested for smoke extraction in a variety of locations.

The mobile fire field air-selling technology and tactics have begun to attract much attention in China. Su Lin and Li Chunxiao have made preliminary research on the mobile fire-discharge and smoke exhaust from the technical and tactical aspects of smoke exhaust.

With the increasing use of mobile smokers in fire fighting in the actual fire fighting, the technical and tactics of fire, smoke and smoke will become more mature.

According to the actual needs of fire fighting and emergency rescue, the fire brigade conducted many drills for the smoke and fire extinguishing of tunnel fires. For example, in June 2011, the Hubei Fire Corps organized a special seminar on tunnel fire fighting and rescue in Enshi Autonomous Prefecture, and proposed the technical and tactical measures for smoke exhausting of mobile smoke exhaust equipment in the rescue of tunnel fires, and compiled the business operation method of mobile fan exhaust training. .

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