EP0627035B1 - Device for protecting buildings against the ingress of harmful gases, especially radon, from the ground - Google Patents

Abstract

The ingress of hazardous gases, especially radon, into buildings is completely or largely prevented by horizontal blocking systems in the floor. A further improvement in protection is to be attained by a device by means of which the rise of the hazardous gases via the vertical walls (2) of the buildings and lateral egress therefrom is largely prevented. In the vertical wall (2) there is a blocking layer (12) forming, with the blocking system in the floor (1) a continuous block consisting of a material barring a hazardous rising gas, especially radon, which is applied via drillings (13) in a row in the wall (2) terminating in the region of the horizontal blocking system in the floor (1). Protection against the ingress of hazardous gases in buildings erected on ground entailing such a hazard.

Description

The invention relates to a device for protecting buildings against the ingress of harmful gases, in particular radon, from the subsoil, a barrier system consisting of several horizontal layers between the subsoil and the interior of the building, said barrier system having horizontal boundary layers made of a plastic material, is built up in the floor and is laterally limited in particular by vertical walls of the building.

It is known that harmful gases, such as the radioactive gas radon and the resulting radon by-products, penetrate from a building site into a building in two ways.

This is done passively by convection. Even slight differences in air pressure are sufficient to transport radon-containing air from the ground into the interior of the building.

The further possibility of penetration is active by means of diffusion.

As a result of Brownian molecular motion, the radon atoms are able to migrate through substances to different degrees. They come from the adjacent earth material through porous cover layers, cavities, thin release agents in the basement or living area.

In houses with known foundation formation, the proportion of gases entering by convection is approximately 90% and that of gases entering by diffusion is approximately 10%. In areas heavily contaminated with radon, however, constant diffusion is sufficient to create a harmful concentration inside the houses.

• a) Meteorologische Luftdruckveränderungen
  Infolge der barometrischen Luftdruckveränderungen in der Außenluft verändert sich auch zeitlich verschoben der Luftdruck der Gase, die im Porenvolumen des Erdreiches enthalten sind.
  Folgt auf hohen Luftdruck eine Periode niedrigen Luftdruckes, so entspannt sich die in der Erde enthaltene Luft. Sie strömt z. B. unmittelbar durch Risse und Spalten im Kellerfußboden in den Kellerraum. Bei nicht unterkellerten Wohnungen, wie sie vielfach in Gebirgsgegenden anzutreffen sind, kann dieser Luftstrom direkt in den Wohnraum einfließen.
  Umgedreht, wenn ein Hochdruckgebiet einem Tiefdruckgebiet folgt, wird wieder Luft aus dem Wohnraum in den Boden nachgedrückt. In dieser Zeit kommt auf diesem Weg durch Konvektion kein Radon aus der Erde. Es dringt dann allein der Diffusionsanteil ein.
• b) Temperaturunterschiede zwischen Gebäude und Außenluft
  Durch die Nutzung der Gebäude wird in der Regel im Gebäude eine höhere Temperatur anzutreffen sein als im Freien. Mit dem Temperaturunterschied ist ein Druckunterschied verbunden. Die warme Luft steigt im Gebäude wie in einem Schornstein nach oben. Von außen und auch aus dem unten anliegenden Erdreich wird Luft nachgesogen.
• c) Eine weitere Möglichkeit, daß Radon passiv in die Gebäude eindringt, ist die Konvektion durch Luftbewegungen im Untergrund. Sie wird hervorgerufen durch Einfließen von kalter Luft ins Gebirge an entfernterer Stelle, die sich im Gestein erwärmt und somit durch ihren Auftrieb nach oben strömt. In ehemaligen Bergbaugebieten wird dieser Prozeß noch durch Hohlräume und vorhandene Gänge von Gruben verstärkt.

The air pressure differences for passive penetration by convection arise in three different ways:

• a) Meteorological changes in air pressure
  As a result of the barometric changes in air pressure in the outside air, the air pressure of the gases contained in the pore volume of the soil also changes with time.
  If a period of low air pressure follows high air pressure, the air contained in the earth relaxes. It flows z. B. directly through cracks and crevices in the basement floor in the basement. In apartments with no basement, as can often be found in mountainous areas, this air flow can flow directly into the living space.
  The other way round, when a high-pressure area follows a low-pressure area, air from the living space is pressed into the ground again. During this time, no radon comes out of the earth by convection. Then only the diffusion part penetrates.
• b) Temperature differences between the building and the outside air
  Due to the use of the buildings, a higher temperature will usually be found in the building than outdoors. A pressure difference is associated with the temperature difference. The warm air rises in the building like in a chimney. Air is drawn in from outside and also from the soil below.
• c) Another possibility for radon to passively enter the building is convection through air movements in the underground. It is caused by cold air flowing into the mountains at a more distant point, which warms up in the rock and thus flows upwards due to its buoyancy. In former mining areas, this process is reinforced by cavities and existing passages from pits.

In the same way, harmful gases of other types can penetrate into buildings built from former landfills.

The diffusion of the radon gas into a building is essentially dependent on the radon content in the subsoil under the building and the nature of the foundation.

In order to reduce or completely prevent the penetration of harmful gases such as radon gas from the building site into the building, it is necessary to counter the convection and diffusion of the gases.

It is known to increase the mechanical resistance between the building ground and the interior of the building. Foils, well-compacted concrete or materials with a similar effect prevent the air from moving further.

However, this method has the disadvantage that the smallest gaps in the barrier system (due to improper processing of the material, material deficiencies, temporal changes in the material, e.g. due to aging, due to the effects of external forces on the barrier with formation of cracks, etc.) have the effect decreased until completely canceled.

At the same time, it is possible that the diffusion process that is always present with a consequent sealing increases due to the creation of a greater pressure difference between the building site and the interior of the building and in this way radon penetrates into the building.

It has also been known from DE-GM 9 108 933.6 that the barrier system consists of one or more barrier layers, one in one barrier layer between two layers that inhibit the passage of air and gas, one for ambient pressure air-carrying intermediate layer having different air pressure is arranged, which is connected at least to a pressure-regulatable air line.

It is known that the air-guiding intermediate layer is arranged to further increase the seal between particularly dense boundary layers, which can consist of a plastic material.

A good sealing effect can be achieved with this device. However, the sealing is interrupted by the vertical walls or by joints that form practical gaps in the barrier system. Radon continues to penetrate the building through these gaps by climbing up the walls and emerging from them from the side. This occurs particularly when a building material that promotes leakage, such as lightweight concrete, is particularly rich in pores as gas or foam concrete and thus favors the ascent of the radon for the walls. The same effect occurs when masonry is made that consists of hollow bricks. These building materials have a wide range of applications because they have many advantages, particularly with regard to thermal insulation.

DE 39 10 440 A1 discloses a measure for weakening or preventing the diffusion of radon gas or radioactive decay products through a wall by arranging a barrier layer in the form of an uninterrupted shell made of rigid polyurethane foam with a closed-cell structure over a wall surface.

This solution ensures that when residues from uranium ore processing are stored in storage silos or waste pits, the escape of radon gas or radioactive decay products into the free outside atmosphere can be largely inhibited. It is necessary to cover the entire inner surface, namely to cover the vertical walls, the floor and the ceilings or the roof surfaces from the inside with such a barrier layer.

However, this solution does not prevent harmful gases, in particular radon, from penetrating into the floor itself and into the vertical walls from the building site. They rise up in the vertical walls and emerge from the walls into the interior at the end of the barrier layer. In the case of multi-storey buildings, all walls and the ceilings must be clad to achieve adequate protection, but radon gas or other harmful gases are always present in the walls, floors and ceilings. There is always a risk of them leaking into the rooms.

The invention has for its object a device for protecting buildings against the ingress of harmful gases, in particular radon, from the building site, a barrier system consisting of several horizontal layers between the building site and the interior of the building, these horizontal boundary layers made of a plastic material has, is built up in the floor and is laterally delimited, in particular, by vertical walls, by means of which a rise of dangerous gases, in particular radon, in the vertical walls and a lateral escape from these into the adjacent interior of the building is largely prevented.

According to the invention the object is achieved in that a barrier layer forming a continuous barrier with the barrier system in the floor is arranged in the vertical wall, said barrier layer consisting of a material preventing the rise of dangerous gases, in particular radon, which is in a row in the wall arranged holes that end in the area of the horizontally arranged barrier system in the floor, and that for connecting the barrier layer in the wall with the barrier system of the floor, a slot receiving the boundary layers of the same protrudes into the barrier layer and is closed by a filler material.

The barrier layer in the wall preferably consists of a synthetic resin or also of a wax, preferably a paraffin.

It is particularly important to arrange the barrier layer in a vertical wall consisting of masonry made of hollow bricks. This also applies to a vertical wall made of a pore-rich material such as lightweight concrete.

Since dangerous gases from the building ground penetrate into a building through convection and diffusion, as described above, it is often also necessary to place such a barrier layer in vertical walls, which consist of a largely dense material, such as concrete, or in a wall made of natural stones bring in. This is especially possible through the use of paraffin as a barrier layer.

It is also possible that, in the case of a joint in the floor locking system over which a wall is arranged, the barrier layer extends above this joint over the entire width of the wall. In this way, the wall is practically provided with a diffusion-inhibiting layer in the form of a seal.

In a further embodiment of the invention, vent holes can be arranged in one or more layers in the wall above the barrier layer, which are in communication with the outside atmosphere. This ensures that, especially in the case of radon by diffusion, residual amounts of radon penetrating the barrier layer can be discharged into the outside atmosphere via the ventilation holes.

It is advantageous if the ventilation bores open into a channel which is connected to the outside atmosphere via one or more openings, an overpressure or underpressure being present in the channel relative to the ambient pressure. With appropriate thermal insulation of the building, the duct can be arranged between the outside of an outer wall of the building and a thermal insulation layer attached to it.

It is furthermore possible for an insulating layer to be arranged on the sides of the wall located inside the building and extending upwards from the floor and covering the wall in whole or in part. This is particularly advantageous if there are ventilation bores in the wall in this section which are connected to the outside atmosphere.

The inventive arrangement of a barrier layer and its connection to the barrier system of the floor; the arrangement of ventilation holes for the discharge of gases into the outside atmosphere as well as the arrangement of an insulating layer provides comprehensive protection against the ingress of dangerous gases through walls into the building. The arrangement of the barrier layer is the prerequisite for overall success.

Fig. 1:

die Vorderansicht der Einrichtung in einer Außenwand eines Gebäudes aus Mauerwerk,

Fig. 2:

die Vorderansicht der Einrichtung in der Zwischenwand eines Gebäudes aus porenreichem Material.

The invention is explained in more detail using an exemplary embodiment. Show in the accompanying drawing

Fig. 1:

the front view of the device in an outer wall of a masonry building,

Fig. 2:

the front view of the device in the intermediate wall of a building made of porous material.

In Fig. 1 the part of a building with a floor 1 and a wall 2 are shown. The wall 2 forms the part of an outer wall in the region of a window 20. In the floor 1, a device for protection against the penetration of dangerous gases, in particular radon, from the building ground can be arranged as a blocking system in a manner known per se.

In the device shown in FIG. 1 there is between two layers 3; 4, an air-guiding intermediate layer 5 having a different air pressure than the ambient pressure is arranged. This intermediate layer 5 is connected in a manner not shown to a pressure-regulatable air line. In the intermediate layer 5, it is possible to build up both positive and negative pressure. The intermediate layer 5 can contain a thermal insulation material. To improve the sealing of this air-conducting intermediate layer 5, horizontal boundary layers 6 are arranged in a manner known per se. In the example shown, they consist of a plastic material. It is for a secure seal even in the joint area between the floor 1 and the wall 2 Expedient to include the boundary layers 6 as sealing elements of the locking system of the floor 1 in the adjacent wall 2. In this case, a slot 21 (FIG. 2) is arranged in the wall 2, which is closed after the boundary layers 6 have been introduced by a filling material such as concrete. It is possible to provide the wall 2 on the inside of the building with an insulating layer 7 in whole or in part. When a window 20 is arranged (FIG. 1), the insulating layer 7 is expediently drawn up to below the lintel. This insulating layer 7 can consist of a film, but also of an insulating paint. This provides additional protection against the lateral escape of dangerous gases, such as radon, from wall 2 into the rooms of the building. These rise up from the building ground via the vertical walls 2 of the building by convection or diffusion. Such an ascent into walls 2, which are very pore-rich or have cavities, is particularly favored. 1 shows a corresponding wall 2 made of masonry 10 with hollow bricks 10 ', which have cavities 11 and between which mortar layers 18 are located. The wall 2 is provided with an interior plaster 8 and an exterior plaster 9.

1, the device according to the invention has bores 13 which generally run obliquely from top to bottom in the wall 2.

A sealant 14, which forms a barrier layer 12, is introduced into the cavities 11 thereof via the holes 13 in the lowermost stone layer of the masonry 10, which is arranged in the area of the barrier system of the floor 1. For a better understanding, the sealing compound 14 in the bore 13 and the barrier layer 12 in FIG. 1 are shown in different hatching. A suitable material for the barrier layer 12 is paraffin. With this material, the masonry 10, that is, the bottom stone layer forming hollow chamber stones 10 'and the cavities 11 filled. The hollow bricks 10 'in the barrier layer 12 with the locking system of the floor 1 are positively connected. This can be done as described above by the slot 21 with the boundary layer 6 extends into the corresponding hollow chamber stone 10 '.

Vent holes 19 are arranged in the upper stone layers of the masonry 10. The air enriched with radon flows out of the cavities 11 in the direction of the arrow outward through these, into which no sealing compound 14 is introduced.

In these areas, radon has already increased in much smaller quantities than in the subsoil, mainly due to diffusion processes. Conversely, convection of radon is largely prevented by the barrier layer 12.

For a safe exit of the radon from the wall 2, it is advantageous to connect it to one another by a channel 15. The channel 15 is then connected to the outside atmosphere via one or more openings 17. In order to achieve a flow, an overpressure or underpressure must be generated in the channel 15. This can be done by measures known in ventilation technology, for example using fans. It is also possible to lead duct 15 into the roof area of a building, in which case the resulting suction can be sufficient for ventilation. Of course, it is necessary to introduce air from the outside atmosphere into the ventilation system. Such a construction of a channel 15 can be achieved particularly advantageously if a heat insulation layer 16 is arranged on the outside of the outer wall is. The space between this and the outside of the wall 2, in FIG. 1, the exterior plaster 9, can then be used as a channel 15 in whole or in part.

It is of course also possible to arrange a channel 15 on a wall 2 of masonry 10 lying in a building, in which the ventilation bores 19 for the outflow of gases, in particular radon, then open. This is particularly necessary if there are load-bearing walls 2 made of masonry 10 with cavities 11 having stone layers in the building. The vent holes 19 can also be arranged offset to one another in the transverse direction. Different positions mean that the ventilation holes 19 to the floor 1 of the building are arranged at different heights.

2 shows a further embodiment of the device. Here, the example of an inner wall was chosen, although it is of course also possible to use it on an outer wall.

The structure of the floor 1 corresponds to the structure as described with reference to FIG. 1. The lower and upper horizontal boundary layer 6, which preferably consist of a plastic film, is guided into a slot 21, which is likewise closed by a filling material, such as concrete, after the boundary layers 6 have been introduced.

In the present exemplary embodiment, the boundary layers 6 now project horizontally into the wall 2 from both sides. The wall 2 consists of a pore-rich material 25, such as lightweight concrete, for example in the form of gas or foam concrete. Its outer layers can be more densely compacted or a plaster can also be applied.

By means of this material 25, the dangerous gas, such as radon, rises by convection and also by diffusion in relatively large quantities.

In this case, the device has bores 22 running obliquely downwards in a row, which lead into the area between the boundary layers 6. A sealing compound, for example in the form of a wax or a synthetic resin, is introduced into this area via the bores 22. This mass penetrates into the pores and closes them, thus forming a barrier layer 24 which is connected to the boundary layers 6 in a form-fitting manner. A continuous barrier is created between the barrier system of the floor 1 and the barrier layer 24. This prevents or greatly reduces the rise of radon.

In the upper area, the wall 2 according to FIG. 2 can be provided in the same way as the wall 2 according to FIG. 1 with ventilation bores 19, through which the radon still passing through the barrier from the sealing compound 24 and the boundary layers is preferably provided via a channel 15 or is discharged via channels 15. Insulating layers 7 can be applied to the sides of the wall 2 in the manner described above.

A further embodiment, which is not shown in a figure, consists in that in the case of a joint in the barrier system of the floor 1, over which a wall 2 is arranged, the barrier layer 12; 24 in the same extends over the entire width of the wall 2. This forms a seal and results in a continuous barrier in the sense of the solution according to the invention.

A barrier system in the floor 1 of a building can also be understood to mean a diffusion-inhibiting concrete layer that sufficiently prevents radon from rising.

By means of the device according to the invention it is achieved that no dangerous gases, in particular radon, can escape through the walls from the building ground, even if they are pore-rich or have numerous cavities, into the interior in an amount which causes a concentration of such gases which is hazardous to health. This is also avoided in particularly critical areas of the room, such as room corners. By means of the device according to the invention, it is possible to ensure adequate protection against rising radon even in buildings which have been built on a building site which contains a large amount of radon.

A particularly useful protection against the penetration of radon is achieved in that the barrier layer 12, 24 in the wall 2, as explained in more detail with reference to FIG. 1, consists of a paraffin. The use of paraffin, for a barrier layer 12; 24 is possible regardless of the structure and composition of the vertical wall 2. The paraffin can be introduced into the wall 2 to be blocked in the heated state. It is advantageous if the wall 2 itself is heated and thus also dried out.

Claims (10)

1. Device for protecting buildings against the ingress of harmful gases, in particular radon, from the ground, a barrier system which consists of a plurality of horizontal layers being constructed in the floor between the ground and the interior of the building and being laterally bounded in particular by vertical walls of the building, the barrier system having horizontal boundary layers made of a plastic material, characterized in that a barrier layer (12; 24) forming a continuous barrier with the barrier system in the floor (1) is arranged in the vertical wall (2), this barrier layer (12; 24) being made of a material which inhibits the rising of hazardous gases, in particular radon, and is introduced via bores (13; 22) which are arranged in a row in the wall (2) and end in the area of the horizontally arranged barrier system in the floor (1), and in that, to connect the barrier layer (12; 24) in the wall (2) to the barrier system of the floor (1), a slot (21) accommodating the boundary layers (6) of the same projects with the latter into the barrier layer (12; 24) and is closed by a filling material.
2. Device according to Claim 1, characterized in that the barrier layer (12; 24) in the wall (2) is made of a synthetic resin.
3. Device according to Claim 1, characterized in that the barrier layer (12; 24) in the wall (2) is made of a wax, preferably a paraffin.
4. Device according to Claims 1 to 3, characterized in that the barrier layer (12; 24) is arranged in a vertical wall (2) consisting of masonry (10) formed from hollow chamber blocks (10′).
5. Device according to Claim 1, characterized in that the barrier layer (12; 24) is arranged in a vertical wall (2) made of a material (25) containing a large number of pores, such as lightweight concrete.
6. Device according to Claim 1, characterized in that, at a joint in the barrier system of the floor (1), across which joint a wall (2) is arranged, the barrier layer (12; 24) extends above the joint over the entire width of the wall (2).
7. Device according to one or more of Claims 1 to 6, characterized in that vent bores (19) are arranged in one or more layers in the wall (2) above the barrier layer, which vent bores (19) are connected to the outer atmosphere.
8. Device according to Claim 7, characterized in that the vent bores (19) lead into a duct (15) which is connected to the outer atmosphere via one or more openings (17), there being a positive pressure or a vacuum in the duct (15) relative to the ambient pressure.
9. Device according to Claim 8, characterized in that the duct (15) is arranged between the outside of an outer wall of the building and a heat-insulating layer (16) applied to said outer wall.
10. Device according to one or more of Claims 1 to 8, characterized in that an insulating layer (7) extending upwards from the floor (1) and completely or partly covering the wall (2) is arranged on the sides of the wall (2) which are located in the interior of the building.

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