The present invention relates to an active fire protection system for a tunnel.

Tunnels, for example road or rail tunnels, are typically equipped with active fire protection systems. Contrary to a passive fire protection system, which includes compartmentaliza- tion of the overall structure through the use of fire-resistance rated walls or floors, an active fire protection system requires some actuation in order to work.

Fires in tunnels have been caused by many reasons, such as car crash, broken catenary leading to fire, overheated brakes catching on fire, or electrical equipment catching on fire. Catastrophic consequences have been observed, for example loss of life, property losses, or long periods of interruption of the use of the tunnel. The particular features of a tunnel provide good conditions for a fire to spread rapidly due to radiation. Charged particles are reflected from the internal surfaces of the tunnel, making it act like an oven. Hot gases accumulating in the tunnel can lead to a flashover. Also, improper ventilation in an emergency situation can lead to ventilated oven conditions, increasing the convection effect and allowing the fire to gain intensity and to spread inside the tunnel. For example, a heavy goods vehicle fire needs only ten minutes to exceed 100 MW and 1200 ^e C, which are fatal conditions. Furthermore, the visibility within the tunnel becomes increasingly hard due to the accumulated smoke. Therefore, a fire in a tunnel should be controlled in its early stages in order to limit its spread.

Advantageously, an active fire protection system allows fighting a fire in a tunnel, in its early stages. However, there are challenges in providing an active fire protection system that is efficient in fighting a fire in its early stages while being easy to build, install, and/or repair.

Known solutions typically provide tunnels with customised active fire protection systems fixed to the tunnel walls or ceiling. These are normally customized for the tunnel on which they are implemented. However, these solutions require a significant effort in planning the installation beforehand. Customised support structures may need to be designed for the purposes of fixing the active fire protection systems on the tunnel. The complexity of this task increases further when a support needs to hold several kinds of components. Also, typically the initial design is performed in a permanent fashion, i.e. during the planning stage it is usually assumed that the installation will not require substantial changes over time. However, this creates difficulties in dealing with a varying risk of fire along the tunnel. If after having made the installation it is found that a certain part of the tunnel requires more fire detector sensors, then it may be difficult to adapt the installed systems, requiring a lot of effort and time in performing the required changes.

The present invention will now be disclosed.

According to an aspect of the invention there is provided an active fire protection system for a tunnel, comprising:

- at least one section comprising at least one pipe for conveying a fire extinguishing agent and at least one duct for extracting smoke from the tunnel, wherein the at least one pipe comprises at least one sprinkler for spraying the fire extinguishing agent, and wherein the at least one pipe comprises at least one inlet vent for extracting smoke from the tunnel to the duct;

- at least one sensor for detecting fire;

- a pump for pumping the fire extinguishing agent to a pipe of the at least one section;

- an exhaust fan for extracting smoke from the tunnel, the exhaust fan being connected to a duct of the at least one section; and

- a computational device for controlling the pump and the exhaust fan based on the at least one sensor,

wherein the at least one pipe and the at least one duct are adapted to be joined with at least one other pipe or duct comprised by another section, respectively, so as to connect at least two sections continuously.

The at least one section may further comprise at least one support adapted to be fixed to the tunnel.

Any of the at least one pipe and of the at least one duct, may be made of any of steel, plastic, aluminium, or fiberglass.

The fire extinguishing agent may be any of water, foam, water/foam, gas, or powder.

The at least one sensor may be any of a heat detector, a smoke detector, a flame detector, or a fire gas detector. The pump and the exhaust fan may be connected to an end of a pipe and an end of a duct, respectively, from an end of the tunnel.

According to another aspect of the present invention, there is provided a method of operating a computational device of an active fire protection system as described above, the method comprising:

- the computational device detecting a fire;

- the computational device waiting a pre-configured amount of time to be overridden;

- if the pre-configured amount of time has expired the computational device proceeding into automatically fighting the detected fire;

- otherwise, the computational device performing at least one command received from a central control room.

The step in which the computational device detects a fire, may comprise the computational device sending a notification to at least one central control room.

The step of the computational device proceeding into automatically fighting on a detected fire, may comprise:

- receiving at least one command from a central control room;

- performing the at least one command.

Embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which:

Figure 1 is a bottom view of three section embodiments joined continuously and installed on the ceiling of a tunnel;

Figures 2a-2b are a perspective view of an active fire protection system embodiment, each figure showing a different moment during a fire incident; and

Figure 3 illustrates a block diagram of a method embodiment for operating a computational device in an active fire protection system embodiment.

In one example, an active fire protection system embodiment is installed in a tunnel. Figure 1 illustrates part of the embodiment in which a bottom view of three sections is shown. Each section has one pipe 101 for conveying a fire extinguishing agent, for example water, foam, a combination of water and foam, gas, or powder, and one duct 102 for extracting smoke from the tunnel. Each pipe 101 of the sections has two sprinklers 103 for extinguishing a fire and each duct 102 of the sections has one inlet vent 104 for letting smoke get into the duct. The pipe and/or the duct may be made of steel, plastic, aluminium, or fiberglass. Also, the sections include a sensor 105 for detecting fire, for example a heat detector, a smoke detector both ionic and/or optical type, a flame detector, or a fire gas detector.

Preferably, each section includes a central sector 106 on which other components may be supported, such as lights, surveillance cameras, or cables. In this example, the sensor 105 is attached to the central sector 106. It is appreciated that many arrangements are possible in this respect, for example having a sensor 105 attached to another part of the section suitable for the detection of fire. Furthermore, the sensors 105 in an active fire protection system embodiment may be scattered through the tunnel in many different ways. For example, they may be scattered through the tunnel in such a way that different segments of the tunnel are monitored by a different number of sensors 105. Likewise, the distance between sensors 105 may vary along the tunnel. In some segments, some sections may even exist without any sensor 105 attached to them.

In the present example, the installation is provided on the ceiling of the tunnel; it is appreciated that many other installations are possible such as on a wall or a floor. Also, the central sector 106 and the components therein installed are optional, as will be apparent from the description throughout. Furthermore, in the present example the sections are attached to the tunnel by at least one support fixed to the tunnel; it is appreciated that there are many ways of attaching a section to the tunnel, for example with a quick release skewer, a push to open lock, or any other mechanism for attaching a section to the tunnel.

The three sections are joined between pipes 101 and ducts 102. Consequently, when extracting smoke or air from the ducts 102 to the outside of the tunnel, the continuous connection established by the joints between ducts 102 will allow to extract smoke or air from the tunnel, through the inlet vents 104 and ducts 102, to the outside of the tunnel. Similarly, when a fire extinguishing agent is pumped into the pipes 101 it will reach the sprinklers 103 where it will be sprayed from the ceiling of the tunnel. Figures 2a and 2b illustrate an active fire protection system embodiment including a pump

201 for pumping the fire extinguishing agent 205 to a pipe 101 of sections similar to the ones in figure 1 . Also shown is an exhaust fan 202 for extracting smoke 206 out of the tunnel, the exhaust fan 202 being connected to a duct 102 of sections similar to the ones in figure 1 .

For the purposes of simplifying the present example, the pump 201 and the exhaust fan

202 are connected to an end of a pipe 101 and an end of a duct 102, respectively, from an end of the tunnel. It will be appreciated that many other arrangements are possible, for example where the structure of the tunnel allows for a different positioning of these components. Furthermore, there may be provided more than one pump 101 and/or exhaust fan

102, for example one at each end of the tunnel, which may be particularly relevant if the length of the tunnel so requires.

The active fire protection system embodiment includes a computational device 203, for example a Programmable Logic Controller (PLC), for receiving data from the sensors 105 and controlling the pump 201 and the exhaust fan 202. Figure 2a illustrates a moment of the method implemented by the computational device, when a fire 204 has struck in the tunnel: the two sensors 105, connected to the computational device 203, detect the fire (indicated by arrows). The connection between the two sensors 105 may be a wired connection, such as a fibre optic cable, or a wireless connection. Figure 2b shows another moment of the method implemented by the computational device 203, in which the computational device 203 activates the pump 201 and the exhaust fan 202. The sprinklers

103, preferably the ones over the fire 204, spray the fire extinguisher agent 205 and the smoke 206 from the fire 204 is extracted through the inlet vents 104 on the ducts 102.

When the pump 201 and the exhaust fan 202 are activated, all the sprinklers 103 and inlet vents 104 may be operational. It is appreciated that it can also be that only the sprinklers 103 and inlet vents 104 nearby the fire 204 are activated. In this respect, proper actuation means for opening and closing the sprinklers 103 and the inlet vents 104 is provided. Also, further data, besides the data from the sensors 105 indicating if a fire has been detected, may also be established by the computational device 203 indicating the location of the sensor 105 that detected the fire 204 within the tunnel. It is appreciated that there are many possible implementations of this aspect of the method, for example by concatenating a sample from a sensor 105 with the location of the sensor 105 on the tunnel, when the sample is transmitted from the sensor 105 to the computational device 203. Or the computational device 203 being pre-configured with a list correlating an identification of a sensor 105 with its location within the tunnel; or alternatively, the list correlating an identification of a section with its location within the tunnel. Thus, any sample received with an identified sensor 105 or section is processed by the computational device 203 to establish a location within the tunnel.

Consequently, the appropriate sprinklers 103 and inlet vents 104 are activated, as well as the pump 201 and the exhaust fan 202. Many alternatives are further possible in this regard. For example, instead of controlling the activation of individual sprinklers 103 and inlet vents 104, the computational device 203 may in turn control the sprinklers 103 and inlet vents 104 of a section as a unit. Furthermore, the computational device 203 may activate several sprinklers 103 and inlet vents 104 surrounding the location where a fire 204 has been detected.

In another example, an active fire protection system embodiment is provided with a connection to a central control room or a fire station, from which the embodiment is monitored and controlled if necessary. It is appreciated that the central control room may itself be situated in a fire station. This connection may be established through the Internet, for example by providing the computational device with communication interface such as a wireless (GSM, UMTS, or LTE) or wired connection. Also, the central control room may be connected to other active fire protection system embodiments, which are all monitored and controlled from there.

In the present example, a particular configuration of the computational device is provided, which is illustrated by the block diagram in figure 3. When a fire is detected at the computational device 301 , the computational device sends a notification to the at least one central control room 302 and waits a pre-configured amount of time for a manual override to occur 303, for example ten seconds. If the pre-configured amount of time has expired 304 it proceeds into automatically fighting on the detected fire 305. Otherwise, the manual override occurs 306 and the central control room remotely takes control of the actuating means of the active fire protection system embodiment.

This arrangement allows sharing the control of the actuating means, when fighting a fire, between the configured logic on the computational device and the central control room. If no manual override occurs (ie the central control room does not take control of the actuating means of the active fire protection system embodiment before the pre-configured amount of time expires), the embodiment proceeds automatically into fighting the fire in accordance with the configurations programmed in it. As explained above, there are many possible configurations in this respect, for example all the sprinklers in the tunnel may be activated or only some of them are activated around the location where the fire was detected. In this last regard, the two or three sprinklers that are the most proximal to the location where the fire was detected may be the ones activated. If the manual override occurs, the embodiment gives remote control of its actuating means to the central control room from which the override originates. Particularly, this situation may be complemented by transmitting possible camera feeds from the tunnel to the central control room.

However, it may even occur that no override occurs, the computational device automatically starts to fight the fire, and afterwards an override is given to certain aspects of the actuation from the central control room, for example by activating additional sprinklers to the ones that have been automatically activated by the computational device.

Thus, in this respect it is possible to detect false alarms by providing a pre-configured amount of time for an override to occur from the central control room. Also, it is possible for the central control room to let the computational device take control and fight the detected fire, and only overriding the actuation if required.

Further, the operation may be complemented by allowing a further portable device to connect to the computational device. The portable device could be carried by a firefighter and, preferably, connected wirelessly to the computational device, allowing for the firefighter to move in the tunnel and further control the operation of the active fire protection system. For example, more sprinklers or inlet vents can be activated as the firefighters sees necessary. This manner of remotely controlling the computational device may be understood as an alternative to controlling the active fire protection system from a central control room or from a physical interface available at the computational device, such as buttons or a screen.

In another example, an active fire protection system may be connected with at least two central control rooms. In this case, when a fire is detected, any of the central control rooms may override the computational device.

In another example, an active fire protection system embodiment is provided with additional features as follows. A control panel may be provided in the computational device, which may be used by firefighters fighting a fire at the tunnel. The control panel may provide a status for the activated components of the system and may also allow for a manual override to occur from there. The data displayed on the control panel may be transmitted to a central control room as well as any other additional data such as camera feeds.

Additional safety means may be provided in connection with an active fire protection system embodiment, such as loudspeakers for aiding any user of the tunnel escaping a fire, electronic signs, or boom barriers controllable by the computational device.

Further safety measures may be provided by an emergency power system in addition to the power source available for powering the system.

Invention embodiments may have some or all of the following advantages:

• reduces the costs of building, installing, and maintaining an active fire protection system for a tunnel

• due to its modularity, it is easy to install or repair; it is also easy to adapt an installed system

• reduces the downtime after an incident, for example by making it easier to replace damaged sections if any

• permits confirmation of a detected fire from the computational device, by a central control room

• allows to monitor and further control the computational device when this it is

fighting a fire automatically

Generally, the terms used in this description and claims are interpreted according to their ordinary meaning the technical field, unless explicitly defined otherwise. Notwithstanding, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or integers are included. These terms are not interpreted to exclude the presence of other features, steps or integers. Furthermore, the indefinite article "a" or "an" is interpreted openly as introducing at least one instance of an entity, unless explicitly stated otherwise. An entity introduced by an indefinite article is not excluded from being interpreted as a plurality of the entity. The features disclosed in the foregoing description, or in the following claims, or in the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for obtaining the disclosed results, as appropriate, may, separately, or in any combination of such features, be utilised for re- alising the invention in diverse forms thereof.

While the invention has been described in conjunction with the embodiments described above, many equivalent modifications and variations will be apparent to those skilled in the art when given this disclosure. Accordingly, the embodiments of the invention set forth above are considered to be illustrative and not limiting. Various changes to the described embodiments may be made without departing from the spirit and scope of the invention.