Wall element for building structures

Abstract

The invention relates to a wall element (1) for building structures, having an outer layer (6), an insulating layer (4) made of a biological material, and an inner layer (5). A high degree of fire resistance is achieved in that supporting beams (3) for supporting the insulating layer (4) are arranged between the outer layer (6) and the insulating layer (5), and in that at least one retaining grid (11) for retaining the insulating layer (4) is provided in the region of the outer layer (6), said retaining grid being fastened to the supporting beams (3). The combination of a clay layer (10) with an embedded metal grid (11a) results in the highest fire resistance rating. The invention also relates to a method for producing such a wall element.

Description

[0001] Wall element for buildings

[0002] The present invention relates to a wall element for buildings, comprising an outer layer, an insulating layer made of a biological material and an inner layer.

[0003] It is well known that natural building materials offer significant advantages because they are generally sustainable, have good structural properties, and are free of harmful substances. Clay, for example, is used very effectively in construction. Insulating materials, those made from organic materials, such as chopped straw, hemp, flax, etc., are often used because of their very advantageous properties in terms of thermal insulation, permeability, CO2 storage capacity, and recyclability.

[0004] One problem with these biological insulation materials is that they are generally not fire-resistant. In particular, in the event of a fire, the fire can destroy the layers that hold the insulation material, causing it to detach piecewise from the wall element and fall out. This is particularly problematic given the stringent fire safety requirements in multi-story residential buildings.

[0005] Clay, on the other hand, is a natural building material and free of environmentally harmful substances. It has excellent fire resistance because clay layers are fired through the application of heat, thus gaining hardness and strength. However, clay layers are sensitive to the effects of weathering and must therefore always be used with appropriate protection.

[0006] Conventional wall elements are not able to simultaneously meet the various requirements for thermal insulation, fire protection, freedom from problematic ingredients, sustainability and reasonable costs.

[0007] DE 20 2010 011 480 Ul discloses a wall element with a filling made of a clay-containing material, which additionally has a reed or coconut insert to regulate the moisture balance.

[0008] FR 2 555 221 A discloses a wall element comprising a perforated cardboard layer reinforced with steel wires. WO 2016 / 055936 A describes a wall structure with a honeycomb-shaped cardboard element designed to improve the adhesion of a casting compound.

[0009] None of the solutions described addresses the question of how the fire resistance of a wall element can be improved.

[0010] The object of the invention is to avoid these disadvantages and to provide a wall element for buildings with which both the other building physics requirements and high requirements for fire resistance can be achieved.

[0011] According to the invention, support beams are arranged between the outer layer and the inner layer to support the insulating layer, and at least one retaining grid is provided in the area of ​​the outer layer to hold the insulating layer, which grid is attached to the support beams. Holding the insulating layer in the sense of the invention also involves preventing the insulating layer from falling out after partial destruction of the outer layer due to fire.

[0012] The particular advantage of the solution according to the invention is that the insulating layer itself does not necessarily have to have special properties with regard to fire protection or its own structural integrity and can therefore be optimally designed to achieve the desired building physics properties and in particular to achieve the highest thermal insulation properties.

[0013] Particularly preferably, the insulating layer consists of chopped straw, which, when highly compressed without chemical additives within the wooden frame, has a comparable insulating value to conventional insulating materials and, in addition, achieves a significantly higher mass, thus offering advantages in terms of sound insulation and summer overheating. The use of other materials, such as hemp, rice pods, wool, or cellulose, is also possible. The special fire-retardant properties of the wall element according to the invention arise in particular from the fact that even if the outer layer has already been largely destroyed by a fire lasting for an extended period, the insulating layer is held together by the retaining grid and can burn slowly without parts becoming detached and falling off while burning. This can significantly improve fire resistance values.In particular, by combining the retaining grid with a clay layer, a fire resistance rating of 90 minutes or more according to DIN 4102-2 or EN 13501-2 can be achieved. The inner layer preferably consists of a carrier board with a layer of clay plaster applied on top. The clay plaster layer is preferably made of straw fiber clay plaster, in which the embedded straw fibers provide structural reinforcement in the form of reinforcement. This clay plaster layer provides excellent protection against fire penetrating from the inside. Furthermore, such a layer has a very positive effect on the indoor climate, as it can absorb or release moisture depending on the prevailing climatic conditions. Therefore, for structural reasons, such a clay plaster layer is highly valued in high-quality residential construction.

[0014] It is advantageous if the outer layer is made of a resin-bonded wood fiberboard. Such a vapor-permeable, moisture-resistant wood fiberboard, often referred to in the construction industry as a DHF board, is essential for the weather resistance of the wall element, especially with regard to the underlying components made of natural materials such as clay and straw. A layer of plaster or other exterior wall cladding can be applied to the outer layer.

[0015] Wooden posts are particularly preferred as support beams. These support beams are typically oriented horizontally when installed, thus providing downward support for the insulation layer, which is arranged in horizontal rows. The spacing of the support beams from each other and from the nearest frame element varies depending on the element size and the structural requirements. This design is particularly suitable for wall elements that do not have a structural function.

[0016] If a wall element is used in prefabricated construction and is also intended to perform structural functions, the support beams can run between vertical posts that carry the vertically acting loads. However, it is equally possible to arrange the support beams vertically and thus also use them as structurally effective components. In this case, the insulation layer is held in place by the grid even during normal operation and prevented from collapsing. In any case, it is also possible to provide openings in the wall element, for example, for windows or similar.

[0017] In order to achieve a fire resistance duration of 90 minutes or more even in the event of an external fire, a fire-retardant clay layer is provided directly behind the outer layer. This is primarily intended to delay the impact of the fire on the insulation layer. In a first embodiment of the invention, the fire-retardant clay layer is designed as a fiber clay board arranged between the outer layer and the retaining grid. To prevent the fiber clay board from falling out as a fire progresses, it is advisable to secure it with appropriate measures. One possibility is to form the clay fiber board over a large area and to construct it in one piece across several support beams in order to ensure appropriate structural integrity.The particular advantage of this design variant is that the retaining grille is additionally protected against fire from outside.

[0018] In a second preferred embodiment of the invention, the fire-retardant clay layer is alternatively designed as a fiber clay panel arranged between the support grid and the insulation layer. In this case, the support grid also secures the fiber clay panel in connection with the insulation layer. Careful selection of the material and correct dimensioning of the support grid are important, as it is positioned in an exposed location. For example, it is recommended that the support grid be made of stainless steel.

[0019] According to a third embodiment of the invention, it is particularly preferred that the retaining grid be at least partially embedded in the fire-retardant clay layer. This provides all-round protection for the retaining grid in its particularly exposed area along the outer layer, mechanically reinforcing the fire-retardant clay layer in the manner of a reinforcement, and simultaneously securing it in its designated location to protect the insulation layer behind it. Using this clay layer reinforced with a metal retaining grid, the fire resistance duration is at its highest.

[0020] A particularly robust and high-quality design is achieved by partially adhering the support grid to the side of the support beams and preferably fastening it there. With sufficiently long exposure to fire, as is naturally the case with the desired fire resistance duration of 90 minutes, it must be assumed that the sections of the support beams located near the outer layer will burn down or lose their structural functions. This also means that components attached there can no longer be held in place. In the preferred design, however, the fastening elements for the support grid can be relocated further toward the center of the structural element, ensuring secure cohesion even if the outer sections of the support beams have already been compromised.Even better protection for the support grid can be achieved by snugly fitting it along the entire side of the support beam and bending it around the support beam in the inner layer. The support grid is then clamped between the support beam and the wood fiberboard and can be attached at any desired location on the side or, if necessary, in the bent area.

[0021] It is particularly advantageous if the insulating layer consists of coarsely chopped straw, preferably dedusted. This has several advantages. By minimizing the dust content and the coarse chopping, which leaves the majority of the stalks intact, a porous structure with very good insulation is achieved, which simultaneously forms a robust, mechanically resilient insulating body, which is essential with regard to undesirable settlement and stability in the event of a fire. Tests have shown that the insulating layer of a wall element manufactured according to the invention, after disassembly, has the shape of a – albeit brittle – plate that can at least bear its own weight.

[0022] In this context, it is particularly advantageous if the chopped straw consists of fiber segments with a length between 3 cm and 8 cm, and preferably between 4 cm and 6 cm. This refers to the average length or the length of the majority of the fiber segments. For example, a maximum fiber length of 5 cm is achieved through appropriate screening, and fine particles and short fiber segments are removed so that the majority of the material consists of fiber segments with a length of 5 cm or just under. This creates a compact yet porous structure with good thermal insulation properties.

[0023] An optimum of the desired properties is achieved when the insulation layer has a density between 95 kg / m 3 and 120 kg / m 3 , preferably between 100 kg / m 3 and 110 kg / m 3This density can be achieved by openly inserting the insulation with mechanical compaction. However, it is particularly preferred to blow in the insulation layer, and this density is controlled by the pressure during blowing.

[0024] The present invention also relates to the use of a wall element of the type described above for the production of skeleton structures. In an alternative variant, the present invention also relates to the use of a wall element of the type described above for the production of prefabricated structures.

[0025] The present invention also relates to a method for producing wall elements for buildings, in which an outer layer is connected to an inner layer via support beams in order to form at least one cavity intended to receive an insulating layer.

[0026] According to the invention, this method is characterized in that at least one holding grid is arranged in the region of the outer layer, which is provided for holding the insulating layer, and in that the insulating layer made of a biological material is blown into the cavity.

[0027] In principle, the wall element described above can be manufactured by first creating a semi-open shell into which the insulation layer is inserted and then mechanically compacted, after which the wall element is closed by applying the second wall layer.

[0028] However, a particularly preferred method according to the invention is for the insulation to be blown into the otherwise largely finished wall element. The particular advantage of this method is that the density of the insulation layer can be adjusted very precisely by regulating the blowing pressure. Density is crucial for the thermal insulation properties and the internal stability of the insulation layer. The blowing opening is created, for example, in a support beam at the edge and is closed after blowing.

[0029] Preferably, chopped straw is blown into the wall element as an insulating layer through an injection opening, through which the injection air can simultaneously escape. The injection takes place under very high pressure to compact the straw into an insulating layer. The injection nozzle is pivoted in various directions during the injection process to prevent the formation of cavities. Since the straw consists of fiber sections and is preferably dedusted, the injection air can be guided out of the cavity via a sieve directly next to the injection nozzle and released into the environment via a suitable filter or cyclone, or alternatively, it can be reused as injection air.

[0030] The present invention will now be explained in more detail with reference to the exemplary embodiments illustrated in the figures. Fig. 1 shows a schematic, partially open plan view of a wall element according to the invention.

[0031] Fig. 2 shows a simplified section along line II -II in Fig. 1;

[0032] Fig. 3 shows a detail A according to a first embodiment of the invention;

[0033] Fig. 4 shows a detail A according to a second embodiment of the invention;

[0034] Fig. 5 shows a detail A according to a third embodiment of the invention;

[0035] Fig. 6 shows a detail A according to a fourth embodiment of the invention;

[0036] Fig. 7 shows a detail A according to a fifth embodiment of the invention; and

[0037] Fig. 8 schematically shows the injection of the inner layer.

[0038] Figure 1 shows a wall element 1, which is preferably intended for use in structures constructed using a skeleton construction method. This means that the structurally supporting structure consists of floor slabs and / or horizontal beams and vertical girders, but the wall elements 1 do not perform any structural functions for the overall structure. The skeleton can be constructed of reinforced concrete or as a timber frame structure. Such wall elements 1 are also referred to in the construction industry as suspended wall elements.

[0039] The wall element 1 has a surrounding frame 2 made of wooden posts, into which support beams 3 are inserted, which are arranged horizontally when installed. An inner layer 4 is inserted in the space between the frame 2 and the support beams 3 and between the support beams 3. This layer is an insulating material consisting essentially of chopped straw, i.e., it is designed as chopped straw insulation.

[0040] Through special processing of the chopped straw in the horizontal component by pressing or compacting after installation, a particularly high degree of compaction can be achieved, thus also enabling improved structural properties in terms of insulation, soundproofing, and suitability for summer use. Blowing in the insulation layer is particularly advantageous. Fig. 2 shows the basic structure of a wall element 1, in particular, that the structure, consisting of frame 2, support beams 3, and an inner layer 4 in the form of chopped straw insulation, is paneled on both sides. Structural cohesion is ensured by an inner layer 5 and an outer layer 6.

[0041] The inner layer 5, which in the installed state is directed towards the interior of the building, consists of a carrier plate 7, which can be, for example, an OSB board (coarse particle board), on which a clay plaster layer 8 made of straw fiber clay plaster is applied.

[0042] The outer layer 6 consists of a diffusion-open, moisture-resistant wood fiber board 9.

[0043] Fig. 3 shows a first embodiment of the invention, in which fiber clay panels 10 are inserted on the inside of the outer layer 6 in the spaces between the frame 2 and the support beams 3. A stainless steel retaining grid 11 is provided within the fiber clay panels 10. This structure is designed to prevent a fire acting on the wall element 1 from attacking the chopped straw insulation for an extended period of time by the fiber clay panels 10. However, even if the fiber clay panels 10 have become ineffective and the chopped straw insulation of the inner layer 4 is attacked, the retaining grid 11 prevents parts of the chopped straw insulation from falling out.

[0044] The support grid 11 is bent in the area of ​​the outer layer 6 and extended along the side surfaces 3a (top and bottom surfaces when installed) of the support beams 3, where it is secured with clamps. Therefore, the structure remains coherent even if the outer sections of the support beams 3 have already burned and lost their structural integrity.

[0045] A sub-variant of the embodiment of Fig. 3 (not shown) is constructed such that a fiber clay board 10 rests over its entire surface on the vapor-permeable, moisture-resistant wood fiber board 9. In this way, the support beams 3 are additionally protected against external fire exposure by the fiber clay board 10, because the fiber clay board 10 then also extends between the support beams 3 and the vapor-permeable, moisture-resistant wood fiber board 9. This can increase the fire resistance duration. The embodiment of Fig. 4 differs from that of Fig. 3 in that the section 11a of the support grid 11 extending along the outer layer 6 is embedded in the fiber clay board 10. Furthermore, the end sections 11b of the support grid 11 are bent over in the area of ​​the inner layer 5 and end between the support beams 3 and the carrier plate 7. They are fixed to the support beams 3 by screws 12.In this way, on the one hand, the inner layer 4 in the form of chopped straw insulation is better held and reinforced in the manner of a reinforcement, but also protected for a longer period from the effects of fire.

[0046] In the third embodiment, which is shown in Fig. 5, the fiber clay panels 10 are each arranged between the holding grid 11 and the straw chopping insulation and are thus additionally held by the holding grid 11.

[0047] A fourth embodiment, shown in Fig. 6, differs from the variants shown above in that the retaining grid 11 runs through the support beams 3 and is clamped there between the support beams 3 and the wood fiber board 9, and is fastened together with the wood fiber board 9 to the support beams 3 by nails or staples (not shown). Fiber clay panels 10 are inserted on the inside. The retaining grid 11 can thus prevent the inner layer 4, including the fiber clay panels 10, from falling out in the event of a fire. This embodiment also offers production-related advantages, since the attachment of the retaining grid 11 is significantly simplified and can be carried out over a large area.

[0048] Alternatively, it is also possible to vary this design variant such that the fiber clay panels 10 are also continuous and are fastened to the support beams 3 together with the wood fiber board 9 and the retaining grid 11. In any case, it is important that the nails or staples with which the wood fiber board 9 and, if applicable, the fiber clay panel 10 and the retaining grid 11 are fastened to the support beams 3 are long enough to hold these components securely even if part of the support beams 3 has burned down in the event of a fire. This maintains the structural integrity of the component as long as the fastening elements are anchored in still intact sections of the support beams 3.

[0049] The fifth embodiment, shown in Fig. 7, largely corresponds to the fourth embodiment of Fig. 6, with the difference that the continuous holding grids 11 are arranged on the inside of the likewise continuous fiber clay panels 10. Fig. 8 shows a schematic representation of the blowing in of the inner layer 4. An injection device 20 is inserted through an opening 3a in a support beam 3 and sealed with a seal 19. An injection pipe 16 with a nozzle 14 conveys the chopped straw together with the injection air into the cavity 13 formed between the inner layer 5 and the outer layer 6. The nozzle 14 is angled so that different areas of the cavity 13 can be reached with the jet 15 by rotating the nozzle 14.

[0050] The blown-in air escapes from the cavity 13 through a sieve 17 arranged around the nozzle 14, retaining the chopped straw. The blown-in air is discharged via a discharge line 18.

Claims

PATENT CLAIMS 1. Wall element (1) for buildings, with an outer layer (6), an insulating layer (4) made of a biological material and an inner layer (5), characterized in that support beams (3) for supporting the insulating layer (4) are arranged between the outer layer (6) and the inner layer (5) and that in the region of the outer layer (6) at least one holding grid (11) for holding the insulating layer (4) is provided, which is fastened to the support beams (3).

2. Wall element according to claim 1, characterized in that the inner layer (5) consists of a carrier plate (7) and a clay plaster layer (8) applied thereon.

3. Wall element according to one of claims 1 or 2, characterized in that the outer layer (6) comprises a resin-bonded wood fiber board.

4. Wall element according to one of claims 1 to 3, characterized in that wooden posts are provided as support beams (3).

5. Wall element according to one of claims 1 to 4, characterized in that a fire-retardant clay layer is provided in the region of the outer layer (6).

6. Wall element according to claim 5, characterized in that the fire-retardant clay layer is designed as a fiber clay plate (10) which is arranged between the outer layer (6) and the holding grid (11).

7. Wall element according to claim 5, characterized in that the fire-retardant clay layer is designed as a fiber clay plate (10) which is arranged between the holding grid (11) and the insulating layer (4).

8. Wall element according to claim 5, characterized in that the retaining grid (11) is at least partially embedded in the fire-retardant clay layer.

9. Wall element according to one of claims 1 to 8, characterized in that the holding grid (11) partially rests on the side of the support beam (3) and is preferably fastened there.

10. Wall element according to claim 9, characterized in that the retaining grid (11) rests against the entire side of the support beam (3) and is bent around the support beam (3) in the region of the inner layer (5).

11. Wall element according to one of claims 1 to 10, characterized in that the holding grid (11) is made of stainless steel.

12. Wall element according to one of claims 1 to 8, characterized in that the holding grid (11) runs between the support beams (3) and the outer layer (6).

13. Wall element according to one of claims 1 to 12, characterized in that the outer layer (6) comprises a moisture-resistant wood fiber board (9).

14. Wall element according to one of claims 1 to 13, characterized in that the fire-retardant clay layer in the form of a fiber clay plate (10) runs between the support beams (3) and the outer layer (6).

15. Wall element according to one of claims 1 to 14, characterized in that the insulating layer (4) consists of coarsely chopped straw, which is preferably dedusted.

16. Wall element according to claim 15, characterized in that the chopped straw consists of fiber sections with a length of between 3 cm and 8 cm and preferably between 4 cm and 6 cm.

17. Wall element according to one of claims 15 or 16, characterized in that the insulating layer (4) has a density of between 95 kg / m 3 and 120 kg / m 3 , preferably between 100 kg / m 3 and 110 kg / m 3 amounts.

18. Use of a wall element according to one of claims 1 to 17 for the production of skeleton structures.

19. Use of a wall element according to one of claims 1 to 17 for the production of prefabricated structures.

20. A method for producing wall elements (1) for buildings, in which an outer layer (6) is connected to an inner layer (5) via support beams (3) in order to form at least one cavity which is provided for receiving an insulating layer (4), characterized in that at least one holding grid (11) is arranged in the region of the outer layer (6), which is provided for holding the insulating layer (4), and that the insulating layer (4) made of a biological material is blown into the cavity.

21. Method according to claim 20, characterized in that chopped straw is blown in as an insulating layer (4) through an injection opening through which the injection air can simultaneously escape.

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