ES2309124T3 - PROCEDURE AND DEVICE FOR EXTINGUISHING FIRE IN TUNNELS. - Google Patents

Abstract

To extinguish a fire in a tunnel (2), e.g. a road tunnel, the site of the fire is isolated by curtains (6,8) on a fire detection signal to give a zone (14) for action. An inert gas floods the zone through flow openings from an external gas supply (31), to reduce the oxygen volume to an inert level. Smoke and fumes are extracted by suction (25) without affecting the inert level. A control unit (23) is linked to sensors to assess the oxygen content in the zone e.g. a smoke detector (5) and oxygen monitor (22), and set the flow of fire extinguishing gas accordingly.

Description

Procedure and device to extinguish fires in tunnels.

The present invention relates to a procedure to extinguish fires in tunnels or constructions tunnel type, in which in this tunnel or tunnel type construction in function of a first control signal is formed by separations an inertization space, which encloses the section affected by tunnel fire or tunnel type construction, and in which at an additional procedural stage the oxygen content in this inertization space through the Sudden introduction of an extinguishing gas in an inert volume. The invention also further relates to a device for performing this procedure, with separations by which you can divide the tunnel or tunnel type construction into areas of concentration, which form spaces of inertization, and with at least an extinguishing gas tank outside the spaces of inertization, which is linked through inlet openings with regarding the fluid technique with the spaces of inertization

Document DE 198 11 851 A discloses a inertization procedure to minimize the risk of and for extinguish fires in enclosed spaces as well as a device To perform the procedure. In this way it is foreseen that, in first, the oxygen content in space is decreased objective (inertization space) to a level of inertization determined basis, and that in the case of a fire decrease additionally the oxygen content already decreased to a level of determined total inertization.

EP 1 103 286 A1 refers to a device for fighting fires in tunnels, comprising  the device a gas tube that acts as a reservoir for a gas inert and opening accessories attached to it and designated as sectoral valves for the release of inert gas through nozzles in a tunnel sector.

By the expression "tunnel type construction", which is mentioned as a complement to the tunnels, they are understood essentially currently mine pits, galleries or spaces similar semi-open ones, which will hereafter respond for reasons of simplicity also to the term "tunnel". For the term "separations" are currently understood as barriers to concentration by which the tunnel can be divided into one or more areas, in which or in which the oxygen concentration (or the extinguishing gas concentration) differs from the other zones of the tunnel to a necessary extent for the extinction effect. Such areas of lower oxygen concentration or higher concentration of Extinguishing gas are currently designated as "zones of concentration".

A method and a device of the type mentioned at the beginning are known for example from DE 199 34 118 C2. The basis of this known method and device as well as the present invention is the so-called "inert gas extinction technique", as it is called the flooding of a space in danger of fire or that is set on fire by gases that displace oxygen as carbon dioxide, nitrogen, noble gases and mixtures of these gases. In this regard, these "inert gases", which are also referred to herein as "extinguishing gases", are generally stored in compressed form in special tanks in nearby spaces. In an emergency, then the extinguishing gas is conducted through a system of pipes and inlet openings corresponding to the inertization space in question. In this regard it is known that the effect of extinction with this inert gas technique is based on the principle of oxygen displacement. While normal ambient air consists in a known manner of 21% oxygen, 78% nitrogen and 1% other gases, for extinction by introducing, for example, pure nitrogen, the concentration of natural nitrogen is further increased in the inertization space in question and with it the proportion of oxygen is reduced. It is also known that an extinction effect then takes place depending on the material when the proportion of oxygen decreases below 15% by volume. In case of fires of solid materials, fires are already suffocated when the oxygen content in the air has decreased from 21 to 11% in volume. In case of fluid fires
and gases may be necessary despite a decrease in oxygen content below 3% by volume.

Both in the procedure and device corresponding known by document DE 199 34 118 C2, as in the present invention is therefore formed by activation of at minus two separations an inertization space, isolating these separations the tunnel in front of and behind the focus of the fire in front of the rest of the tunnel relatively tightly to the gases These separations can be configured by mechanical devices, these mechanical devices being sheet curtains or down or telescopic screens or also smoke curtains, but also so preferred "gas flow barriers" that work so similar to air curtains at entrance to warehouses. The first control signal mentioned at the beginning to activate the separations can be triggered for example by emergency switches or on the initiative of a central surveillance center (for example, tunnel control, fire station), or also automatically by means of a fire detection device that will be done reference later.

During the recent tunnel catastrophe of Gotthard has shown again that in the fight against fires in tunnels the smoke generation is one of the biggest problems. This occurs especially in tunnels through which vehicles circulate, since in them as a rule the tires of vehicles feed the fire, which causes a huge smoke generation and also the formation of harmful vapors. Already in the preceding catastrophes of the Mont-Blanc tunnel and from the Tauern tunnel it became clear that it was certainly the very large heat generation, although especially the huge smoke generation, which made it impossible for days to approach to the sources of fire. The present invention is responsible for this problematic, as an objective it was considered to perfect a procedure and a device for extinguishing fires in Tunnels or tunnel type constructions of the type known by the DE 199 34 118 C2 in such a way that the smoke problem will be solved effectively in connection with the technique of extinguishing by inert gas.

This objective is solved by procedure for extinguishing fires in tunnels or tunnel type constructions of the type mentioned at the beginning, in which in a third stage of the procedure, a content of oxygen that can be predetermined in the inertization space by means of regulated additional extinguishing gas supply.

The objective is also solved by device for performing this procedure, which contains an oxygen measuring device, which emits measurement signals to a control unit, which regulates the gas supply of extinction and, if necessary, fresh air or oxygen to a space of inertization

The present invention therefore provides a procedure and a corresponding device with which you can extinguish a fire, such as those triggered for example in the Mont-Blanc tunnel, in the Tauern tunnel and recently in the Gotthard tunnel, with the extinction technique by known and very effective inert gas, and at the same time they can take the measures to dissipate the smoke that appears. Since the inertization space formed by the separations is, as explained above, a space largely isolated from the rest of the tunnel in a tight way to the gases, and since the conservation of the concentration of oxygen that allows extinction in the inertization space is very important for the lasting extinction of the fire, it cannot dissipate from this space of inertization without more smoke, since thus the oxygen concentration or the gas concentration of extinction in the inertization space would change so unwanted With the method according to the invention it is measured by both permanently the oxygen content in the space of inertization and if necessary extinguishing gas is introduced into the inertization space. Therefore, a possible compensation can be compensated loss of extinguishing gas due to smoke dissipation through a Extinction gas monitoring. Therefore, the advantages of a effective and modern inert gas extinguishing technique can apply, despite a strong generation of smoke or gases harmful, to fires in tunnels.

For this, the device according to the invention provides an oxygen measuring device, which sends measurement signals to a control unit, which regulates the extinguishing gas supply and, if necessary, fresh air or oxygen to the inertization space.

Advantageous improvements of the invention are indicated in the dependent claims.

Thus, for the process according to the invention it is provided for example in an additional procedure stage that is activated based on a second control signal a smoke dissipation device in the inertization space. From this mode the smoke dissipation device does not have to be present itself in the space of inertization; rather, it can also be provided centrally or at same time for two spaces of inertization and be connected only through suction ducts with their own spaces. In this way it is only important that the power of the device smoke dissipation according to the volume of the space of 1 or 2 inertization spaces. Thus the second control signal can fire in turn, just as described already previously for the first control signal, by emergency switches or through a lookout central, or automatically using a device fire detection referred to below. In In any case, this second control signal, which communicates a smoke generation, can also be used to stop the entrance of more vehicles in the tunnel, activating for example a signal of stop located at each tunnel entrance.

Preferably, the first and second signals of control come from a fire detection device, whereby an association of the fire focus with one or more sections susceptible to tunnel inerting or tunnel type construction. A device of fire detection known in itself, which is installed in the tunnel or tunnel type construction such that they can detect existing or emerging fires by areas so exhaustive, and that in case a fire or a fire is detected emergent fire by means of a detector, emits the first signal of control to activate the separations and, if necessary, the second control signal to activate the smoke dissipation device in the area in question. In this way it is understood by the expression "fire detection device" preferably a suction device with which through a system of pipes with suction openings are permanently aspirated representative parts of the tunnel air and are conducted to a detector to detect a fire parameter. In this way understood by the expression "fire parameter" quantities that are subject to the environment of an emerging fire or an existing fire at measurable variations, for example the ambient temperature, the percentage of solid or fluid material or gaseous in ambient air (formation of smoke particles or aerosols or vapors), or ambient radiation. In the case more simple, the detector of a fire detection device of this type consists of a smoke sensor, which is oriented then exclusively to the fire parameter "particles of smoke".

In case the fire arises at the limit between two concentration spaces, it is detected by two devices  of adjacent fire detection, which is formed according to another improvement of the process according to the invention a double inertization space which then consists of two zones of adjacent concentration. This is planned according to the procedure that does not activate the central separation between two adjacent sections that can be inerted from the tunnel or the tunnel type construction when the detection device Fire reacts in both sections.

For the device according to the invention it is intended as improvement to each inertization space a smoke sensor that emits the first and / or the second is associated control signal to the control unit. The advantages of a sensor Smoke of this type has already been explained above; if a sensor Smoke of this type is present in each inertization space, that is to say in each zone of concentration of the tunnel, this simplifies of course the location of the fire focus.

Preferably, the measuring device of oxygen and / or the smoke sensor are part of the device fire detection by aspiration already described previously, which leads to a fire warning facility Clear and compact

An improvement, according to which to each inertization space is associated one of the control units  described, also serves to simplify the device according to the invention and especially for redundancy. To this In this regard, it is also preferably provided that each unit of control present additional inputs to receive command signals which are issued from a central surveillance post. A sign of command of this type can mean for example "total flood with N 2, that is nitrogen "to decrease the content in oxygen in the inertization space. This may be necessary when vehicle tires or fuel burn. In this way it is Obviously the total flood order is given with N_ {2} at central surveillance post, for example tunnel surveillance or a fire station, when it is guaranteed that it has been evacuated the inertization space in question. A command signal from this type could also mean however "flooding with air u O_ {2} ". Such an order may be useful when the fire has been safely extinguished and oxygen concentration should rise rapidly again to a non-dangerous level to living beings.

Although with the procedure and the device according to the state of the art constituted by document DE 199 34 18 C2 for each inertization space a deposit is planned of extinguishing gas, it can be absolutely advantageous to have only a single central extinguishing gas tank, which is attached, in terms of fluid technique, through a network of ducts With each space of inertization. An extinguishing gas tank Central of this type may consist of a battery of bottles of extinguishing gas, but also an auxiliary conduit or other auxiliary space of the tunnel forms the container for this deposit of extinguishing gas In any case, the gas tank of extinction must be sized to simultaneously flood two adjacent inertization spaces, specifically for the case in that the fire arises at the boundary between two spaces of concentration, then forming the double inertization space already described above.

A more detailed explanation is given below. preferred embodiment of the invention with the aid of a He drew.

They show:

Figure 1, a schematic representation of a tunnel, which is divided by separations into zones of concentration; Y

Figure 2, a partial longitudinal section schematic of a concentration zone of such a tunnel, in which a cargo vehicle burns.

Figure 1 shows a representation schematic of a tunnel 2, whose tunnel walls 18 in the inside the tunnel is arranged for example a device of fire detection by aspiration with suction ducts 1 and suction openings 3 provided therein. These ducts 1 suction are arranged for example on both sides of a lane indicated with and equipped with reference number 21 in the longitudinal direction of tunnel 2 and joined in terms of technique of fluids with a detector 5 disposed outside the conduit passable from the tunnel or its walls 18. The detector 5 serves as known way to monitor aspirated air samples by fire parameters and is electrically connected to your  Once with an evaluation unit 7.

Tunnel 2 can be divided transversely to its longitudinal direction by a total of four separations 4, 6, 8, 10, in three zones 12, 14, 16 concentration. Of this separations three, specifically separations 4, 6 and 8 are totally descended while separation 10 is found still in half state lowered. While in this example they are provided mechanical separations in the form of rolling doors, for such separations of course can also be used air curtains, which belong to the state of the art. In In any case, the separations stagnate zones 12, 14, 16 of concentration in a largely gas-tight manner about with respect to others and in front of the rest of the tunnel and act therefore as concentration barriers

Outside each inertization space are provided in the embodiment shown in this case 9, 11, 13, 15, 17, 19 extinguishing gas tanks containing a reserve of extinguishing gas in the form of nitrogen at high pressure and are linked in terms of fluid technique with entrance openings 20 in or on the walls 18 of the tunnel.

The method according to the invention and the device shown by way of example in figures 1 and 2 for  performing the procedure take advantage of the "technique of extinction by inert gas ", that is to say the flooding of a space at risk of fire or set on fire by means of a gas extinction, in this case preferably nitrogen. From this mode the device 1, 3, 5, 7 fire detection detects by fire 5 a fire, in this case by example in concentration zone 14. Depending on a first control signal or depending on a second control signal, also intended to activate a dissipation device of smoke (25; explained in more detail by figure 2) is immediately activate the separations 6, 8, that is to say they descend, so that with the concentration zone 14 a inertization space that encloses the area of the tunnel affected by The focus of the fire. At the same time it is activated with the first control signal an inertization device that enters from the reserve containers 13 and 15 through the openings 20 of rapid and very sudden entry of extinguishing gas into the concentration zone 14. At the same time the oxygen content in the concentration zone 14, which is explained in more detail below by figure 2, and by means of a control unit it is tried to maintain, once reached, a concentration of oxygen or extinguishing gas that allow extinction, introducing in a regulated manner additionally extinguishing gas in the concentration zone 14. By therefore, by rapid flooding with extinguishing gas, by example nitrogen, the oxygen content in space is reduced of inertization in an inert volume that rises in a fire of solid material at approximately 11% by volume and in a fire of fluids or gases at approximately 3% by volume.

Figure 2 shows a longitudinal section schematic of a concentration zone 14, specifically as basically corresponds to the concentration zone 14 of the figure 1, but with separations 6, 8 and 10 of another type and equipped with a extended technical device First of all it has to be staked that the Burning cargo vehicle represented in Figure 2 is not represented in scale as to the height of the tunnel duct passable. Normally between the top edge of a vehicle loading and the tunnel roof is only available approximately 1 to 1.2 meters. For this concentration zone 14 represented in Figure 2, which in turn forms an inertization space, are represented as separations 6, 8 by way of example two curtains air doubles, which belong to the state of the art and are suitable for largely insulating gas tight the concentration zone 14 of the tunnel sections adjacent.

Also in this case in zone 14 of concentration of figure 2 is installed a device fire detection with a suction duct 1 and openings 3 suction provided therein. Through these ducts air samples are permanently aspirated interior space of the concentration zone 14, which is indicated by arrows directed vertically upwards. These air samples are fed to a measuring unit and detection, which consists of a measuring device 22 of oxygen, a detector 5 to detect a fire parameter, also in an evaluation unit 7 and finally in a fan 24 to aspirate air samples. The concentration value of oxygen measured with the oxygen measuring device 22 is issues to a control unit 23, which compares the value of concentration measured with a predetermined value and adopts measures corresponding. Detector 5 also emits, when it has discovered a fire parameter, through its unit 7 of evaluation, a first control signal to the control unit 23. This then activates separations 6, 8, after which isolates concentration zone 14 from the rest of the tunnel largely gas tight way. In addition, unit 23 of control emits a signal to the extinguishing gas tank 31 and starts the inertization operation by sudden introduction of gas from extinction from each tank 31 of extinguishing gas in zone 14 of concentration

If detector 5 also discovers the parameter of fire "smoke", then emits a second control signal  to the control unit 23, whereby it activates a device 25 smoke dissipation. At the same time, device 22 of oxygen measurement measures the oxygen content in space 14 of inertization and emits signals corresponding to unit 23 of control, with which this, after reaching the oxygen concentration  or the concentration of extinguishing gas that allows extinction, continue to additionally feed extinguishing gas from the tank 31 to keep the oxygen content low and that allows the extinction in the inertization space 14, although the device 25 smoke dissipation influence the composition of gases within the space

By additional command signals 27, 28, for example they are emitted from a tunnel surveillance to the control unit 23, either a total inertization or a supply of air or oxygen from reservoirs 29, 30 of reserve additional.

Claims (10)

1. Procedure for extinguishing fires in tunnels or tunnel-type constructions, in which this tunnel or tunnel-type construction is formed based on a first control signal by separating an inertization space, which encloses the tunnel or construction section tunnel type affected by the fire, and in which in an additional procedure stage the oxygen content in this inertization space is reduced by the sudden introduction of an extinguishing gas to an inert volume, characterized in that in a third process stage an oxygen content is maintained that can be predetermined in the inertization space by means of regulated additional extinguishing gas feed, and because in a further process step a smoke dissipation device (25) is activated based on a second control signal in the inertization space. 2. Method according to claim 1, in that the first and second control signals come from a fire detection device, by which it is performed an association of the focus of the fire with one or more sections that they can be inerted from the tunnel or tunnel type construction. 3. Method according to claim 2, in the one that the central separation between two sections that can inert adjacent to the tunnel or the tunnel type construction not is activated when the fire detection device reacts in both sections. 4. Device for carrying out the method according to one of claims 1 to 3, with separations (4, 6, 8, 10), by means of which the tunnel (2) or the tunnel type construction can be divided into zones (12, 14 , 16) concentration, which form inertization spaces, and with at least one reservoir (9, 11, 13, 15, 17, 19; 31) of extinguishing gas outside the inertization spaces, which is connected through input openings (20) regarding the fluid technique with the inertization spaces, characterized by an oxygen measuring device (22), which emits measurement signals to at least one control unit (23), which regulates the supply of extinguishing gas and, where appropriate, fresh air or oxygen in an inertization space, and a smoke dissipation device (25), which is activated based on a control signal in the inertization space. 5. Device according to claim 4, in the that to each inertization space is associated a sensor (5) of smoke emitting a control signal to the control unit (23) for form an inertization space by separations and / or to activate the smoke dissipation device (25). 6. Device according to claim 5, in the that the oxygen measuring device (22) and / or the sensor (5) of smoke are part of a device (1, 3, 5, 7, 24) for detecting suction fires. 7. Device according to one of the claims 4 to 6, in which to each inertization space is associated a control unit (23). 8. Device according to one of the claims 4 to 7, in which each control unit (23) presents inputs for receive command signals (27, 28), which are emitted from a post central surveillance 9. Device according to one of the claims 4 to 8, which also presents a network of conduits through which a gas tank (31) is connected to the fluid technique of central extinction with each inertization space. 10. Device according to one of the claims 4 to 9, wherein the gas tank (31) of central extinction or and / or also each deposit (9, 11, 13, 15, 17, 19) Additional extinguishing gas is housed in one or more auxiliary spaces or an auxiliary space of this kind in itself form the container for the extinguishing gas tank.