New Technology for Fire Fighting in Tunnels


A high-tech pulse equipment for extinguishing tunnel fires has been successfully developed by the Swedish Fire Science and Technology Department not long ago, which has been highly valued by the International Fire Technology Committee (CTIF).

There are many fire hazards in tunnels

With the increasingly busy traffic, many countries have rapidly developed train and automobile tunnel traffic, but there are many fire hazards in the tunnel and the danger is great. In recent years, there have been many tunnel fires with heavy losses, such as the English Channel Tunnel Fire and the Austrian Lambuet Tunnel Fire in Europe alone. According to the recent inspection of multinational tunnels by the International Fire Protection Technical Committee, many tunnels currently have various fire hazards due to design and management defects:

1. There are few ventilation and exhaust channels. There are few ventilation and exhaust channels in the tunnel, which will inevitably lead to poor ventilation and rapid temperature rise. Many harmful gases will stay in the tunnel, which will not only harm human health, but also cause fires and explosions, causing heavy losses.

2. Lack of emergency exit and exit channels. At present, the appearance of tunnels in various countries is relatively beautiful, the structure is different, and the height and density are also different, but they all lack emergency exit and exit passages. Many road tunnels can only enter and exit from both ends, and subway tunnels can only enter and exit from the station. Although some tunnels have a small number of entrance and exit passages, the signs are not conspicuous, or they are blocked for other purposes. In the event of a disaster such as a fire, not only firefighting and ambulance vehicles will not be able to arrive at the scene quickly, but also victims will be difficult to escape smoothly, which will inevitably cause major disasters.

3. Few fire rescue equipment. Many tunnels lack fire extinguishing water sources and fire extinguishers, fire hydrants are too far apart, and rescue tools are few. In the event of disasters such as a fire, rescuers cannot extinguish the fire and provide disaster relief in time.

4. There are many dangerous goods transported in the tunnel. Chemicals and various flammable and explosive materials are often transported in tunnels. Due to poor ventilation, many harmful substances are trapped in the tunnel, which is prone to fire and explosion when encountering high temperature and open flame. In addition, there are many risk factors that people do not pay attention to or understand. As stated in the multiple fire case reports of the International Fire Protection Technical Committee, organic matter powders such as flour, coffee powder, and milk powder transported through the tunnel are mixed with dust in the tunnel, and fires will also occur when encountering high temperature or open flames. . Many tunnel fire hazards mentioned above lead to many tunnel fires every year.

Tunnel fire test

In order to test the important role of high-tech pulse fire extinguishing equipment in extinguishing tunnel fires, under the auspices of the International Fire Protection Technical Committee, the Swedish Fire Protection Association invited fire experts from Britain, France, Germany and other countries to conduct a fire extinguishing test in a 260-kilometer tunnel on the west coast of Sweden . At the beginning of the test, they lit a fire in the middle of the tunnel, and the environmental protection department immediately detected the temperature and the content of various harmful gases in different stages of the fire. The fire department then quickly extinguished the fire with new technology equipment. Since then, many tests have been carried out, and the results of each test have confirmed that using this new equipment to extinguish fires has the following advantages:

1. Fast fire extinguishing speed. When using this equipment to extinguish a fire, firstly a large number of mist-like fine water droplets are sprayed, which absorb heat and cool down quickly, and the fire can be quickly controlled and extinguished within a few minutes.

2. Save a lot of water for fire fighting. When this equipment is used to extinguish a fire, a large number of mist-like small water droplets sprayed by 1 liter of water can extinguish a fire of 200 square meters. Compared with fire-extinguishing equipment such as water spray, it can save 95% of fire-extinguishing water.

High-tech pulse fire extinguishing equipment

The pulse fire extinguishing equipment developed by the Swedish Fire Science and Technology Department mainly uses water as a fire extinguishing agent. The unique advantage of water is that it can quickly absorb a large amount of heat, and the higher the temperature, the more heat it absorbs. This equipment sprays a large amount of mist water droplets to the fire site when extinguishing the fire, absorbing heat rapidly, causing the temperature of the fire site to drop rapidly, so that the fire is controlled and extinguished. This device can spray a large amount of water mist within 10 to 50 milliseconds, and the sprayed water mist can cover 200 square meters per liter of water. Not only the fire extinguishing speed is fast, but also a large amount of fire extinguishing water is saved and the environment is protected.

The high-power high-pressure system in this equipment can accelerate the switch cycle of the water spray valve, and each switch only takes 10 to 30 milliseconds, with fast speed, more water spray, fast heat absorption and fire extinguishing speed. The high-pressure valve is installed between the driving equipment and the water storage tank to separate the driving fuel and fire extinguishing agent. When the fire is extinguished, the high air pressure forces the water in the water storage to flow out. After the equipment is started, the valve will automatically open to spray water to extinguish the fire.

At present, this equipment has been mass-produced, and fire departments in many countries have used or are planning to use this equipment to extinguish tunnel fires. It has a variety of specifications, it can be portable and mobile, and it can be fixed at the fire place to extinguish fire. It can also be installed on a helicopter to extinguish forest fires or assist ground firefighters to extinguish fires.

Firefighting Equipment in Tunnels

When using this new equipment to extinguish tunnel fires, matching fire prevention equipment should also be prepared, such as infrared detectors, temperature sensors, program control computers and tunnel water transport trucks. When the temperature in the tunnel is higher than the limit value, the temperature-sensitive alarm will send out a signal. At this time, the pulse fire extinguishing equipment will automatically start to spray mist water to extinguish the fire. If it is a smoldering fire, use an infrared detector to quickly determine the source of the fire, and immediately cool down to extinguish the fire.

The International Fire Protection Technical Committee calls on the fire departments of various countries: with the increase of tunnels, on the basis of doing a good job in tunnel fire prevention, they should consider using this new type of pulse fire extinguishing equipment