Evacuation of people from tunnels and other closed rooms during fire involves many problems, in particular when the smoke emission is substantial. Modern tunnels are often built with pavements or cornices along the side walls to facilitate evacuating, but during fire conditions the tunnels in practise will be filled up with smoke within short. Persons in the area accordingly will have problems with finding the pavements, and cannot without problems be guided by such devices towards more safe areas.

Even if this invention has been developed to be used within tunnels, it may also be used in connection with other closed rooms, such as engine rooms, corridors and cabins, onboard vessels and on platforms. Everything which in the following description is said about use within tunnels, accordingly may be extended to use also in connection with other types of closed rooms where persons are staying or passing. Even if light is installed in many tunnels, the light beams will be attenuated and dispersed by smoke particles, so that the light does not give any helpful information for people present. In addition the electrical lines which supply power to such light sources will often be damaged during fire, or the fire may even begin in such lines and cables. Accordingly existing light and possibly installed fans, which otherwise could have removed some of the smoke, will be defective.

The object of the present invention mainly is to give a higher visibility within zones or areas in tunnels during fire, and at the same time to produce a more useful air quality in these zones, so that persons within the tunnel more easily may move towards safer zones within the tunnel or preferably may leave the tunnel completely. The zones with increased visibility and enhanced possibilities for breathing will also facilitate the work for the rescue personnel who more easier may understand the damages and

easier may find their way to the site of an accident.

Within some existing tunnels a ventilation plant has been installed. In this connection it may be referred to US patent No. 1.643.868 describing a ventilation system for tunnels, in which air ducts are provided below the track bed with air-inlets arranged where the ducts ends in the free, and return ducts, including fans, are arranged along the tunnel top. It should be emphasized that such ventilation systems are rather expensive as they include ducts both in the bottom of the tunnel for input of air as well as ducts in the tunnel top for exhausted air, at the same time as both types of ducts require fans or pumps to maintain the air circulation. In this patent it is not stated the amount of air that has to pass through the system during a certain time period, however, such conditions are mentioned e. g. in Swedish printed application No. 7211738, in which it is stated that the amount of air varies strongly, and is independent of the traffic through the tunnel, but may amount to 100 m'per sec. Ventilation systems normally will give such a high air circulation or air replacement within the tunnel that a possible fire will increase due to the supply of fresh oxygen, and accordingly generating smoke easily may be dissipated along a longer length of the tunnel than in corresponding plants without ventilation. Existing ventilation plants are also not designed to give narrow zones of a higher air quality along the tunnel.

From mining industry it is previously known to arrange devices for protection of personnel against fire damp which may gather within the mine. In German patent No. 1.948.278 a tent is described which may be collapsed along the mine wall in a stand-by position, but which may be deployed during emergency conditions and supplied with pressure air, prefer- ably from an upper tent pole within the tent.

When modern road and train tunnels with heavy traffic are considered, it should be pointed out that persons which are within such tunnels when a fire with unhealthy smoke and gas emissions starts, as a rule will have no specific remedies designed to bring them out or guide them away from a dangerous area to more safe zones or possibly quite out of the tunnel.

Security plants which today are planned and operated, e. g. in long road tunnels, are only based on alarm systems and communication systems. Accordingly both detection systems for detecting of smoke and harmful gasses and also systems for warning against such detrimental conditions at the tunnel entrance to prevent people from driving into harmful and dangerous areas, and also telecommunication plants including emergency phones from which it is possible to ask for assistance from relief stations, are developed.

When modern road tunnels and other high traffic tunnels, often built for two-way traffic within one single tunnel course, are considered, a collision will often lead to heavy damages as both traffic files within the tunnel will be blocked up and the warning systems will not in time prevent travellers to enter the tunnel from both sides.

During such conditions, and if a fire develops in damaged vehicles, all people within the tunnel will be exposed to mortally danger, and at the same time the access for relief forces is bared by the many vehicles and the smoke emission, including toxic fire gasses.

The type of disasters which can take place in long tunnels with heavy, modern traffic cannot be avoided by solutions according to the prior art mentioned. Depending of the circumstances previously known ventilation plants may make conditions worse and accordingly reduce the possibilities for survival within the tunnel, as a powerful air supply via a ventilation plant will stimulate the fire, once started. In a similar manner a relatively strong air flow may lead to a faster transportation of the smoke gasses along the complete tunnel, so that it is filled up with smoke and more dangerous conditions develop, even at large distances from a possible fire.

The present invention will facilitate access for rescue and relief forces into the tunnel to assist injured people, and at the same time the visibility and the fresh air supply will be sufficient so that persons who are not injured, may move themselves into safer zones without being exposed to harmful concentrations of fire gasses, even when the remaining parts of the tunnel's cross section substantially is filled by smoke.

A further object of the present invention, and then in particular related to specific embodiments of the same, is to provide emergency light along the courses with enhanced visibility, and in particular an emergency light of a type which does not need separate power supply and where the power supply is not very vulnerable against high local temperatures.

A further object of the invention is to screen off at least one zone having an acceptable visibility and acceptable fresh air supply, from the smoke filled area of the tunnel, and then preferably by means of screens which also may protect against heat radiation.

Finally it is an object of the present invention to provide means which contribute to the removal of smoke and soot particles from the evacuating zones, and at the same time these means will contribute to a better visibility and protection against heat radiation.

It should be noted that the preferred embodiment of the present invention also is the simplest, most reliable and less expensive embodiment, which also may be used in all existing and also in new tunnel plants without large costs.

However, this solution will, all the same, provide zones with relatively fresh air and relatively good visibility, which zones may be used both by rescue personnel on their way into the tunnel and by injured people on their way out from the tunnel, and at the same time this solution will provide waiting zones adapted for relaxing and medical examination of injured persons before transportation out into fresh air takes place. This preferred solution includes only features as stated in claim 4.

More sophisticated solutions may also be produced, and will be preferred in large tunnel plants. Such solutions also will be understood from a method and a system according to the claims below.

To give a more clear understanding of the invention it is referred to the detailed embodiments below, and to the accompanying drawings, in which: Fig. 1 illustrates a cross section through a road traffic tunnel provided with a system according to the present invention.

On the figure some of the details which may be required to give a practical implementation of the system, are omitted to avoid crowded drawings including unnecessary details. And the scale is not necessarily the same for the different components.

The main principles of the invention is briefly explained in connection with an embodiment shown in Fig. 1, in which the cross section through a tunnel with evacuating equipment according to the invention is depicted.

A cross section through a road traffic tunnel 1 is shown on Fig. 1, including a carriage way 2, pavements 3,4, a support wall 5, air pipe 6, air-powered lamps 7, and water pipe 8 with nozzles 9. On Fig. 1 the cross section of a corridor or an evacuation course 10 is also assumed with dotted lines, however, only to show the location of the evacuation zones. This corridor may be built with or without physical limitations to the surroundings.

The main idea is to arrange air supply pipes 6 of a relative coarse dimension within the tunnel 1, preferably at or above a normal persons hight. These pipes 6 are connected to aggregates (not shown) which may be placed within shafts or quite outside of the tunnel 1, and these aggregates, which may be operated in any conventional manner by combustion engines and/or electrical motors, are made and connected in such a way that they can blow large amounts of fresh air into the pipes 6, which preferably are laid out substantially along the complete tunnel length. The aggregates do not have to be in continuous operation, but may be started automatically or manually at any sign of fire. All the same the air pipe 6 which is used, may be the pipe normally used for ventilation of the tunnel, and such a solution may be preferred as it then is ensured that the pipe is applicable and usable at any time, and this regularly used pipe may then easily, when a disaster or an accident takes place, in an automatic or manual manner be changed to another mode of operation, so that the pipe then may act as an air pipe according to the present invention.

The pipe or the pipes 6 is (are), in accordance to the present invention, provided with openings such as recesses or nozzles 11, at spaced intervals along the pipe. When the

aggregate (not shown) is working, air will be blown into the pipe 6, possibly from both sides of the tunnel or from a plurality of shafts along the tunnel, and this clean air will be forced out through the nozzles 11 or the recesses along the pipeline. This clean or fresh air then will replace smoke and impurities and build up a zone of relatively clean air resulting in enhanced viability along the tunnel, and at the same time persons in the tunnel will have a more clean air for breathing. It is important that the air supply per time unit is correct, i. e. so low that not a substantial ventilation draught is generated along the tunnel. The amount of supplied air for a tunnel having a normal cross section area, may be approximately 50 1/min per metre tunnel. The air supply should not be so large that smoke in the tunnel is widely distributed.

According to a preferred embodiment one or more such pipes 6, which may be made of metal, may be arranged 2-3 m above a pavement 3,4 which is arranged close to the tunnel wall. However, such air supply pipes may possibly be arranged quite down on the tunnel bottom, e. g. alone or as a supplement to pipes mounted at a higher level, to enhance the breathing possibility at ground level.

The air pipes 11 may be of a previously per se known type, and each single nozzle may be pre-set to deliver a suitable amount of air at the prevailing air pressure within the pipe 6, just where each single nozzle is arranged.

The evacuating system may preferably be provided with further remedies which may be of great value in emergency cases.

Along the pipe 6 which supply clean air with some over- pressure, lamps 7 operated by the supply of pressurized air and being of a type per se known in connection with mining, may also be arranged. If the pressure within the pipe 6 is sufficient to operate such lamps 7, the lamps may e. g. be arranged in connection with some or all nozzle openings 11, which in all cases shall deliver fresh air to the area around the pipeline. If the air pressure within the pipe 6 is not high enough to operate such air operated lamps 7, these may be operated by a separate air supply line (not shown on the Figure) having a higher pressure and being

adapted to a separate supply aggregate or a separate pump.

As an alternative the air supply pipe may along all the tunnel consist of only one relatively thin metal tube which mainly is dimensioned and calculated for operation of the pressure air operated lamps 7, and this pipe may in addition be provided with minor nozzles 11 adapted to expel clean air to the tunnel at wanted locations. All or some of these nozzles may possibly be remotely operated, so that exactly the nozzles that are to be activated may be controlled from a monitoring centre, in accordance to the present situation.

At several places along the tunnel, e. g. in connection with all or some of the nozzles 11 or the lamps 7, there may be arranged fans operated by pressurized air, which fans in particular may take care of two tasks, viz. assisting with removing smoke and fire gasses out of the tunnel 1 or assisting with removing smoke and fire gasses away from the tunnel walls and the evacuation course 10, at which places the pavements 3,4 are situated.

Finally the system may include a water supply means designed as a water pipe 8 associated with atomizing nozzles 9 along the pipe. By emission of atomized water droplets a powerful cooling may be obtained, which may be essential when persons are to be rescued from a tunnel fire, and the small, hovering water droplets will adhere to smoke and soot particles in the air and cause precipitation of the same, which again enhances the viability within the tunnel. Such water nozzles 9 may also be pre-set and possibly remotely operated so that they may be opened/closed, or controlled according to the present situation.

More details may be mentioned in connection with this idea, e. g. use of Alvenius-tubes with fast coupling connections, and the possibility of arranging evacuating pockets representing safe zones within the tunnel, while fans will move the smoke gasses to other zones.

At local positions within the tunnel the air filled pipes 6 may lead out into tube sections or tunnel sections provided with entrances with air locks having so large cross sectional dimensions that persons may move into these tubes, and internally along these tube sections to safer zones or to safer"protection-rooms"with fresh air supply, from

which zones or rooms injured persons later on may be collected by means of vehicles or like.

Zones such as corridors 10 with a low smoke intensity and fresh air supply, may also physically be confined from the surroundings by means of curtains 12 which may be pulled down or rolled up and which possibly may be moistened.

The capacity of aggregates, pumps, nozzles and valves, may be calculated in each single case. Long tunnels may be separated in sections which may be supplied with air/water separately from the tunnel entrance or from different shafts or cross connections.

The system comprises in its simplest embodiment only one single air pipe 6 having a relatively large transportation capacity, provided with fixedly arranged and pre-adjusted and pre-set nozzles 11, arranged at intervals along the pipe. These nozzles normally will be adjusted in such a manner that the nozzles close to the compressor will have a small nozzle opening, while the nozzles arranged a long way from the compressor will be adjusted so that they have a somewhat larger nozzle opening. These conditions are adjusted so that mainly the same air flow is obtained from all nozzles along the pipeline. When long tunnels are considered, the plant may of course be separated in several independent sections. For relatively short tunnels where no surveillance systems are available, it will be a simple solution to implement the different remedies mentioned, with a possibility for manual start or triggering. It should be noted that the amount of air used, should be adjusted in relation to the tunnel plant in question, and in all cases also in such a manner that the air supply does no give a strong flow or air within the tunnel, but only a sufficient supply of fresh air so that the visibility is increased and it is possible to breath close to the air pipe 6. The assumed air supply of approximately 50 1/min. per running metre of tunnel, has be found to be a useful value for road traffic tunnels having two opposite directed files. All the same this air supply is not critical, as the conditions will be acceptable for a rather wide rage of air supply values as long as the air supply does not generate a strong draught in zones within the tunnel. Across the nozzles a differential

pressure of at least 4 bars may be used.

In connection with large tunnel plants with monitoring rooms and surveillance by means of detectors and possible video cameras, the start and control of the plant may also be undertaken from such a control room. In these cases it may be preferred to use nozzles which may be remotely operated by opening/closing, controlling, so that the operation may be adjusted according to the present accident.

When the water supply is considered, this should not be excessive, only sufficient to generate a small area with atomized water close to the evacuating zone. Tests have shown that a water supply of approximately 100 1/h for each metre tunnel may be suitable for a road traffic tunnel of usual dimensions.

The initiation or start of the plant may take place automatically, controlled by smoke, temperature, and/or photo detectors; or a manual start may be used, controlled by people in the tunnel or by surveillance personnel, e. g. from separate operator rooms.

As mentioned above the method and the system may also be used for other closed rooms where people are staying or have to pass during fire or other situations with smoke and/or gas emission.

The system may be designed so that it is activated according to the present situation, or in such a manner that it always is operative. With continuous operation there is no risk that the system when seldom needed; without a warning will not operate adequately.