SYSTEM FOR PRESSURIZING THE INSIDE SPACE OF A BUILDING, E.G. THE STAIRWAY OF AN APARTMENT BLOCK, IN A FIRE SCENARIO

The object of this invention is a system for pressurizing the inside space of a building, e.g. the stairway of an apartment block, in a fire scenario as well as for removing smoke from the relevant space, which system comprises a fan for pressurizing as well as one or more openable and closable louvers that are in connection with the outdoor air for removing smoke.

The basic task of smoke management in a fire scenario is to keep the means of egress free of smoke and to safeguard the unhindered evacuation of people from the building. In apartment blocks pressurization of the stairway, hall and elevator shaft has become general, in which case a large amount of clean air is brought to these spaces in a fire scenario. The spaces are kept overpressurized with respect to their environment. A fan is needed for this, with which the pressurization is achieved. In this way the means of egress are kept free of smoke and the evacuation of people from the building is safeguarded. In addition to improving evacuation safety, pressurization creates substantially better operating conditions for those performing rescue work in a fire scenario.

In addition to this the stairway is provided with smoke extraction, which most generally is located e.g. in the top part of the stairway and via which the fire gases are ventilated to the outdoor air. An outward opening louver without a fan or as an additional component of a fan is most generally used in smoke extraction. Typically the fire brigade starts the smoke extraction from a separate switch after arriving at the site of the fire.

The operating principle is that after a fire has broken out in some apartment, the fire detector of this apartment transmits a signal to the pressurizing fan, which starts. Typically the pressurizing fan is disposed e.g. in the bottom part of the stairway. Overpressure is produced in the stairway when the fan is operating, which overpressure prevents the access of smoke from the burning apartment to the stairway as long as most of the doors are closed. In the stage when the fire brigade arrives at the site, the smoke extraction and ventilation is generally started.

A modern system thus requires a separate fan and smoke extraction louver. The purpose of the invention is to achieve a new and better appliance than before. The system according to the invention is characterized in that the system comprises an appliance that is in connection with the outdoor air, which appliance comprises an air duct, a fan arranged in the air duct and one or more openable and closable louvers between the air duct and the outdoor air.

One preferred embodiment of the system according to the invention is characterized in that the direction of rotation of the fan can be changed, in which case the first direction of rotation is intended to pressurize the stairway and the second direction of rotation is intended to enhance smoke extraction via the opened louvers.

Another preferred embodiment of the system according to the invention is characterized in that there are two openable and closable hinged louvers, to both of which an arm is connected for moving them, and in that the apparatus comprises linear motors, by means of which the arms are arranged to move and the louvers to open and close by means of them.

Some of the advantages of the invention that can be mentioned are that it improves personal safety during a fire in an evacuation situation and in those apartments that are located in the same stairway as the burning apartment. The invention facilitates the design and implementation of pressurization and smoke extraction compared to existing solutions. The appliance used in the system according to the invention is compact.

In the following, the invention will be described in more detail by the aid of a preferred embodiment with reference to the attached drawings, wherein

Fig. 1 presents a side view of an appliance according to the invention with the louvers open.

Fig. 2 presents an A-A section of Fig. 1.

The drawings thus present an appliance 1 according to the invention for pressurizing the inside space of a building, e.g. the stairway, and for removing smoke from the relevant space. Both functions are integrated into the same

appliance. The appliance is disposed e.g. in the top part of the stairway, preferably on the roof of it, such that it is in connection with the outdoor air. The appliance is thus generally disposed on the roof of the building. The appliance comprises walls 3, which border e.g. an essentially rectangular shaped air duct 4 inside them. The top part of the duct is in a normal situation closed with the louvers 2, but the drawings present a situation, generally a fire scenario, in which the louvers are open. The louvers 2 are hinged at their outer edges to the wall 3. The louvers are provided with arms 5, which are moved backwards and forwards in the longitudinal direction with linear motors 6 for opening and closing the louvers. The air duct 4 is protected at it bottom end with a protective net 7.

An axial fan 8, the direction of rotation of which can be changed, is installed in the duct 4. The structure of the axial fan is not described in more detail in this context because it can be any prior-art solution whatsoever that is suited to its purpose. The system according to the invention and the appliance 1 used in it operate e.g. as follows:

A fire breaks out in some apartment, in which case the fire detector of the apartment gives a signal to the appliance 1 according to the invention. In this case the louvers 2 of the appliance open and the axial fan 8 starts, blowing clean outdoor air into the stairway. In this case overpressure (e.g. approx. 50

Pa) is produced in the stairway, which prevents the access of fire gases into the stairway. The overpressure of course starts to decrease when a door is opened, e.g. when residents leave their apartments out of the bottom door of the stairway. In that stage when the smoke finally starts to enter the stairway, the fire brigade personnel can start smoke removal with the appliance according to the invention. This occurs from a separate switch, by means of which the direction of rotation of the axial fan 8 is changed and the fire gases start to exit into the outdoor air via the duct 4 of the appliance 1.

It is obvious to the person skilled in the art that the invention is not limited to the embodiments presented above, but that it can be varied within the scope of the claims presented below. For example, the cross-sectional shape of the duct 4 of the appliance 1 can be other than a rectangle. There are one or more louvers 2 and the shape of them can vary. Likewise their opening and closing mechanism can also be other than what is presented above.