EP2360326B1 - Construction element for constructing the external shell of buildings - Google Patents

Description

The invention relates to a device for the construction of the outer shell of buildings according to the preamble of claim 1. Such a device is made DE 200 14 795 U known. In particular, the invention is based on a component comprising an outer layer, a supporting structure, an insulating layer and an inner layer, wherein the inner layer consists of a planking, to which a clay building material layer is applied.

As a component in the above sense primarily wall elements for the outer walls of houses are meant, but the present invention is also applicable to horizontally arranged structural elements, such as floor, roof or ceiling elements. The term outer shell should make it clear that it is the components of the invention are those that take over static tasks in addition to the tasks of highly efficient thermal insulation and fire protection.

The present invention is intended in particular for structures with particularly high demands on ecology, sustainability and energy efficiency, such as passive house buildings or low energy houses. It should be ensured in particular a favorable room climate.

It is also known, walls of buildings with insulating layers of compacted and with binders or z.T. toxic additives against fire and pest exposure provided layers of vegetable material such as cellulose fiber or flax fiber. Furthermore, it is known to use building materials based on clay in various ways for the production of walls for buildings.

• hervorragende Wärmedämmung;
• ausreichende Stabilität;
• vorteilhaftes Raumklima;
• hohe Brandbeständigkeit;
• kostengünstige industrielle Herstellbarkeit;
• sehr gute Recyclierbarkeit; und
• beste Ökobilanz im Vergleich zu allen üblichen Bausystemen.

The US 7,073,306 B shows different ways of constructing such walls. However, so far no wall construction has become known which satisfies all the requirements for an ideal highly efficient building envelope in a sufficient manner, namely:

• excellent thermal insulation;
• sufficient stability;
• favorable room climate;
• high fire resistance;
• inexpensive industrial manufacturability;
• very good recyclability; and
• best eco-balance compared to all common building systems.

Object of the present invention is to provide a device that meets these requirements equally well. Another object of the present invention is to provide an economically efficient and resource efficient method of manufacturing such a device.

According to the invention, these objects are achieved by the features of claim 1. In particular, it is provided that the insulating layer of untreated shrubs, preferably straw chaff, consists, and that the outer layer of a permeable during the production process air-permeable and in the finished passive-house airtight, but diffusible remaining planking is constructed. The inner layer can also be constructed as shown above.

Preferably, the outer layer or occasionally the inner layer of a perforated wood or Holzwerkstoffbeplankung is constructed. But it can also be other forms of perforation such. Slots are used to achieve the building physics desired properties. In itself, however, the natural limited air permeability of wood-based panels is sufficient in many cases, especially if additional measures are taken.

The planking can not only be done by panels, it is also a wood Rauschalung used, especially with double-sided non-woven clay layer and with ventilated facade. This results in a completely open to diffusion structure, but is relatively expensive.

An essential aspect of the present invention is to utilize the excellent thermal insulation properties of untreated shredded plants in a novel manner which has significant advantages over baled straw, or chemical shredded shreds or processed fibers, by utilizing the wall structure of the present invention , together with a through this enabled Einbringtechnik for chaff compensates the immanent disadvantages of untreated straw chaff as insulation material, namely increased risk of subsidence and worse fire behavior against bales straw or stabilized straw chop.

The technical advantage of using straw chop instead of using bale straw is the increased flexibility in planning a building since there is no need to comply with grid dimensions that result from the usual use of plant straw bales from the dimensions of these typically parallelepiped pressed bales. Another significant advantage of Invention is the much more cost-effective way of introducing plant straw as an insulating material in industrially prefabricated components. The increased costs for processing and incorporating plant straw have hitherto prevented the widespread use of the sustainable natural insulation material, which is available in large quantities at low cost, and so far prevented significant use in the construction industry.

The advantages of using untreated plant straw chaff compared to using chemically stabilized chaff is that, in addition to avoiding material costs, the entire problem of introducing additional amounts of water, or solvent-like chemicals, or other chemicals incorporated into a generally airtight wall construction for a stabilization process must be completely eliminated.

The possibility of mechanical stabilization of shreds by mixing suitable fibers in the chaff is complex and the required uniformity of the mixture is a technically demanding and risky process that is superfluous by the inventive design of the corresponding parts of the building envelope.

From an economic point of view, the development of a large mass potential of harmless and renewable insulation will be of great importance in the future. For example, because the necessary stabilization of insulating cellulose with boron salts places a potentially mutagenic substance on the market in large quantities. An even bigger problem is the use of polystyrene insulation for building façades, which is used in huge quantities. The admixture of highly toxic polybrominated flame retardants to polystyrene, which is necessary for such building insulation, causes mutagenic toxic chemicals to be put into circulation massively, their industrial applications for other purposes by REACH regulation is / is banned in Europe.

The planned EU Passive House standard for new buildings is one of the most effective parts of the EU's energy efficiency strategy. It becomes problematic only through environmentally damaging insulation materials, if they have to be produced in large quantities and released latently into the biosphere, as long as they can not be replaced by technically inherently safe, pollutant-free insulation technologies, such as these.

This high inherent safety of the vegetable hull insulation according to the invention is achieved by its function as a core in the system of capillary conductive inclusion in diffusible layers, the necessary fire resistance "at the forefront" of layers of Faserlehmbaustoff is made highly effective.

In addition to the thermal insulation properties to meet the requirements of fire resistance and the formation of a correspondingly advantageous indoor climate, a Faserlehmbaustoffschicht is applied to a corresponding planking on the inside of the room. The fiber-clay building material layer is dimensioned so that it can simultaneously fulfill the function of an installation level and a fire-retardant layer.

In this way, on the interior side, a thermal and hygric storage mass lying in the optimal weight range for highly insulated buildings is produced, which can also be used for component activation. For the component activation concrete is usually used as mineral building material. This is limited in lightweight construction possible and structurally problematic in conventional lightweight constructions.

Here, the structure of the invention provides a timely alternative. As a heavy mineral component here a clay building material is used, which makes it possible to combine the principal advantages of solid construction with the advantages of lightweight wood construction, as specially fiber clay plaster due to its high elasticity, its similar expansion and shrinkage behavior and its capillary conductivity in contrast to Concrete but also plasterboard can be permanently optimally connected with statically effective wooden structures. The resulting design has an order of magnitude better energy and eco-efficiency. (Wiss. Evidence available).

With the two construction variants, a vapor diffusion capacity increasing towards the outside of the building is produced. The fire safety is achieved by the clay building material layer, which stabilizes in case of fire due to the heat in the sense of a burning process and the static load capacity of the construction together with the insulating layer unexpectedly long and permanently protected from the fire.

Inner layer and outer layer may be formed in particular of wood-based panels of appropriate thickness, it being possible depending on structural and static requirements, both the inner layer and the outer layer structurally effective train or optionally form only the inner layer statically.

A particularly preferred embodiment of the present invention provides that the planking of the outer or inner layer consists of a wood-based panel having a perforated grid or other perforation. To this In the first instance, the blowing out of the component with insulation chaff can be carried out efficiently, and in the finished state, a capillary, moisture-conducting but at the same time airtight layer is formed.

In particular, it is advantageous in this context if the planking has an air permeability of between 0.5% and 5%, preferably between 1% and 3%. Air permeability is the area fraction of the openings (e.g., holes or slits) in the total area of the component. In this case, the outer plate, so for example, an array of holes with 16 mm diameter, which are arranged in a square grid with a pitch of 100 mm, so that the hole proportion is about 2%. But it is also possible to use a limited air permeability through the full material.

The orientation of the straw fragments in the component in relation to the heat flow direction passing through the wall structure is, in addition to the cutting length, of great importance for the heat transfer resistance lambda of the straw used. This orientation is caused by the applied insertion technique.

The assumption that the crushed-straw fragments would be arranged in a barely directed, chaotic random position as they were blown in by the transport air turned out to be false in all length categories, and the influence of a deviation from directionlessness had been underestimated.

The compensation of this effect by simply increasing the insulation thickness would be uneconomical due to follow-up costs.

In order to remain at an economic insulation thickness, the design value of the straw bale insulation must be <0.045 W / mK.

This is achieved by optimizing the length of straw chopped into the components of the outer shell and then mechanically pouring them in so that the majority of the half-crumb pieces are aligned transversely to the heat flow direction. The shaking of the component at a suitable frequency during the filling process may be advantageous for the orientation of the straw particles.

In order to achieve the required settlement safety, it has been found that a second step is necessary in which additional insulant is introduced by injection (or other methods) until a settling-proof density is achieved. This step can in principle account for only horizontal components of the precast system.

Since the required amount of insulating material to be introduced in a second operation is now greatly reduced, the specification of a minimum percentage of perforation for component layers for the passage of the transport air will no longer make sense. It could also be used methods for producing sufficient overcrowding of the insulating layer, which do not require transport air.

It is particularly favorable if the clay building material layer of the inner layer is designed as a biofiber clay layer. Biofiberlehm is known and in the EP 0 903 328 A described in its production and application. It is essential that the clay mass in the preparation of suitable vegetable fibers are mixed in order to improve the building physics properties accordingly. In the context of the present invention, an essential feature of biofiber clay is to provide additional safety against spalling in case of fire and to create a porosity by burning out the biological components, the fire resistance due to reduced susceptibility to crack analogous to the effect of porosity of clay tiles in the burning process on elevated. In particular, the significant increase in fire resistance through the use of Biofaserlehm is a surprising result that greatly improves the value and usability of the device. Fire resistance values under load of REI-90 have already been achieved with the present invention and up to REI-120 are expected.

Furthermore, preferably the clay building material layer of the inner layer is applied to a plaster base, such as reed stucco and / or a grid. In addition, it can be provided that in the clay building material layer as installation level installation pipes, such as pipes for process water, electricity, but also heating or cooling coils are embedded. Particularly advantageous here is the good thermal conductivity and the high specific gravity of the clay as preferably after EP 0 903 328 A used.

However, it is preferable to an alternative construction variant. In this case, the classic plaster carrier reed stucco omitted, as well as in principle a grid. Instead, brackets (for example in a grid of 10 x 10 cm) are placed in the sheathing of shingle or OSB so that they reach just below the future surface of the biofiber cladding layer applied in the factory (eg 65 mm brackets, the 34 mm in the 35 mm installation level protruding from BFL). This novel connection system from support structure to biofilm level has two main advantages:

In contrast to the reed stucco, such a nailing with clips can be cost-effectively integrated into an automated production process according to the state of the art.

Given a suitable composition of the biofiber clay layer, this plane, (presumably) from 35 mm thick, can improve the statics of the component by virtue of this effective way of introducing shear forces into the construction.

Side advantages are that the installations can be optimally distributed on the surface before the operation Benageln without a plaster carrier makes editing difficult and reduces the height.

By this novel frictional connection of Biofaserlehmschicht with the supporting structure, the shear forces occurring in the earthquake are substantially attenuated by the viscoelastic property of a suitably assembled Faserlehmbaustoffschicht and so there is a failure of the construction only at higher quake levels than in conventional design.

Furthermore, the fire resistance of the structure improves by the improved connection of the clay building material layer in the remaining static-efficient zone of the structure in the event of a fire.

The static construction is particularly preferably formed of insulating stands, laminated wood web supports, which are usually arranged perpendicular to the wall plane.

Furthermore, the present invention relates to a method for producing a structural element for the construction of the outer shell of buildings, in which a supporting structure is produced, which is provided with an inner layer and an outer layer, wherein a clay building material layer is applied to the inner layer. According to the invention it is provided that in the cavity between the inner layer and the outer layer an insulating layer of untreated shredded shrubs, preferably straw chaff is blown, wherein the injected air escapes through the outer layer.

In the manufacturing process, another particular advantage of the invention perforated planking on the inside or outside comes to light. Namely, it can be ensured by the large-scale escape of air in the injection process, a particularly high and efficient filling of the components without having to set elaborate measures to avoid cavities. In this case, injection openings are created at suitable points of the component and the plant shred is blown at these points. The necessary compression is mainly due to the inventive design achieved because the Ausblasluft large Ausströmquerschnitte are available. In addition, shaking can be done to improve compaction. Separate exhaust openings, which must be closed afterwards, need not be provided thanks to the outer or inner layer, which is permeable to air depending on the design variant. However, it is possible to provide ventilation openings at the end faces of the component when the injection speed is to be increased.

A particularly advantageous feature of the method according to the invention is that it does not set a chaotic random position of the individual half fragments of the insulating layer, but that in the finished product, the individual half fragments of the insulating layer of untreated shrubs are preferably aligned transversely to the heat flow direction. This means that the individual parts of the insulating layer are arranged substantially parallel or at a very acute angle to the plane of the plate. Investigations have shown that more than 90% of the straw fragments are at an angle <10 ° to the plane of the plate, if the injection is carried out carefully and if necessary further measures, such as shaking, are carried out.

It is particularly favorable if, before the insulating layer is injected, a diffusion-open cover layer, preferably a nonwoven layer, preferably a fleece fleece, is applied to the planking of the perforated or otherwise perforated outer layer. The particular advantage lies in the fact that a dust load during manufacture can be prevented, since this cover layer retains dusts in the manner of a filter that arise during the blowing. This nonwoven layer subsequently also serves as an additional plaster carrier for the clay plaster layer and forms an airtight composite with the latter, so that these perforations do not pose any danger to the passively compliant airtightness of the building envelope. (This function of this so-called clay nonwoven technology has already been proven by measurements in a research and demonstration project).

Furthermore, the perforation allows a capillary conductive contact between the capillary conductive insulating material and a kaput very well conductive clay plaster building material layer. Due to the difference in the low equilibrium moisture content of clay plaster (preferably qualitatively the Biofaserlehm according to EP 0 903 328 A accordingly) and the higher equilibrium moisture content of plant fibers, since the clay plaster layer is kept dry by the construction, a permanent capillary suction effect for moisture from the insulation layer out in the direction of the component surface. This capillary transport potential is more efficient than the transport effect of the simultaneously existing opposite process of vapor diffusion against the vapor diffusion resistance of the inside of the insulating layer lying building material layers of the construction. These structural-physical dynamic effects are used here to indirectly secure the long-term stability of this construction against microbial decomposition processes by, for example, avoiding condensation water drainage and, according to experience, even minor design defects tend to remain without damage. The design is thus more forgiving than conventional designs, which are based on the concept of a theoretically ideally dense, static enclosure of capillary non-conductive insulation materials in lightweight walls.

Fig. 1

eine teilweise axonometrische Ansicht eines erfindungsgemäßen Bauelementes;

Fig. 2

einen Horizontal-Schnitt durch ein solches Bauelement;

Fig. 3

einen Vertikal-Schnitt durch ein solches Bauelement;

Fig. 4

und Fig. 5 Ansichten einer alternativen Ausführungsvariante von vorne bzw. von oben.

As a result, the present invention will be explained in more detail with reference to the embodiments illustrated in FIGS. Show it:

Fig. 1

a partial axonometric view of a device according to the invention;

Fig. 2

a horizontal section through such a device;

Fig. 3

a vertical section through such a device;

Fig. 4

and Fig. 5 Views of an alternative embodiment of the front or from above.

The inventive component according to Fig. 1 . Fig. 2 and Fig. 3 basically consists of an inner layer 1, a supporting structure 2, an outer layer 3 and an insulating layer 4, which is arranged in the cavity between the inner layer 1 and the outer layer 3. The inner layer 1 consists of a planking 6 with a wood-based panel on which a grid 15, for example made of reed, is applied as a plaster base to carry a clay building material layer 5 of biofiber clay. Alternatively, the plaster base may consist of a plurality of brackets, which are only partially driven into the one planking 6 and accordingly protrude beyond the surface. In the Lehmbaustoffschicht 5 installation pipes 16 for heating and plumbing or electrical cables are embedded.

The outer layer 3 consists of a planking 7 of a wood-based panel in which holes 9 are provided, for example, in a rectangular grid with the pitch a of 100 mm, which have a diameter d of, for example, 16 mm. This results in a hole proportion of about 1.8%. The wood-based panel of the planking 7 is covered with a layer 8 of Flachsvließ with thin plaster. In the planking 7 closable openings 11 are provided for blowing the insulating layer 4.

The main static function is represented by the supporting structure 2, which is constructed of web supports. These web supports consist of posts 12 which are interconnected by a thin-walled plate 13. This ensures a high bending stiffness with minimum heat transfer. Shear loads are absorbed by the planking 7 of the outer layer 3, which is firmly connected to the double-web carriers of the supporting structure 2. In order to limit the cavity for receiving the insulating layer 4 is on both sides of the plate 13 each a soft-fiber plate 18 used as an insulating element.

The face plates 10 are made of wooden strips, web supports or wood glue carriers 19, are used in the insulation elements 20 to improve the insulation properties. The insulating elements consist of soft fiber plates 20, which are optionally reinforced by wooden strips 19. Out Fig. 3 It can be seen that the closable openings 11 can be used for blowing the insulating layer 4 in the soft fiber boards 20 when access via the end faces is desired and possible, but alternatively or additionally the closable openings 11 can be provided in the planking 7 of the outer layer 3 , In Fig. 4 this is shown in detail.

Fig. 5 shows alternatives to the arrangement of the closable openings 11 for blowing the insulating layer. 4

In an alternative embodiment of the method according to the invention, not yet completed, the component is placed horizontally and the insulating layer 4 is poured in. In order to allow a sufficiently dense filling must be shaken either during or after pouring and / or compacted. Surprisingly, this makes it possible to achieve a corresponding alignment of the fiber elements parallel or at least approximately parallel to the plane of the plate, and above all, the finished component is settling safe. This means that even with prolonged use in a vertical state, the entire wall element remains filled with insulating material. After the appropriate compaction, the wall element is completed by applying the inner layer or outer layer.

The present invention makes it possible to represent very energy-efficient components, which consist largely of biological, renewable building materials and at the same time show high thermal insulation properties with extremely good fire resistance.

Claims (15)

1. Structural element for constructing the outer shell of buildings, comprising an outer layer (3), a supporting structure (2), an insulating layer (4) and an inner layer (1), said inner layer being designed as a wooden planking (6) onto which a layer of clay material (5) is applied, characterised in that the insulating layer (4) consists of untreated vegetable chaff, preferably chopped straw, and that the outer layer (3) is designed as a wooden planking (7), which is at least partially air-permeable during the production process and remains open for diffusion in the finished state.
2. Structural element according to claim 1, characterised in that a diffusion-open cover, preferably a further layer of clay material, is applied on the outer layer (3).
3. Structural element according to any of claims 1 or 2, characterised in that the planking (7) of the outer layer (3) is a board of wood-based material, which together with the outer plaster layer has sufficient diffusion capability.
4. Structural element according to claim 3, characterised in that one of the plankings (7) has an air-permeability of 0.5% to 5.0%, and preferably 1% to 3%.
5. Structural element according to any of claims 1 to 4, characterised in that the clay-material layer (5) of the inner layer (1) is realized as a layer of organic fibre-clay material preferably applied on a plaster base.
6. Structural element according to any of claims 1 to 5, characterised in that installation pipes (16) and/or heating and/or cooling batteries are imbedded in the clay-material layer (5).
7. Structural element according to any of claims 1 to 6, characterised in that the supporting structure (2) is formed of insulation studs, glued-timber joists, or I- joists.
8. Structural element according to claim 7, characterised in that the inner layer (1) is made of boards of wood-based material or other panels that are statically effective, such as gypsum-fibre-panels, or panels made of bamboo-based material, which are rigidly attached to the supporting structure (2) for taking up shear forces.
9. Structural element according to claim 7, characterised in that the outer layer (3) is made of boards of wood-based material or other panels that are statically effective, such as gypsum-fibre-panels, or panels made of bamboo-based material, which are rigidly attached to the supporting structure (2) for taking up shear forces.
10. Structural element according to any of claims 1 to 9, characterised in that the individual pieces of straw making up the insulating layer (4) of untreated chopped straw are preferably oriented tranversely to the direction of heat flow.
11. Method for manufacturing a structural element according to claim 1 for constructing the outer shell of buildings, where a supporting structure (2) is built, which is provided with an inner layer (1) and an outer layer (3) and where a layer of clay material (5) is applied on the inner layer (1), characterised in that an insulating layer (4) of untreated vegetal chaff, preferably chopped straw, is introduced, and preferably blown, into the hollow space between the the inner layer (1) and the outer layer (3).
12. Method according to claim 11, characterised in that the air blown in will at least partially escape through the planking (7) on the outer layer (3).
13. Method according to claim 11, characterised in that the air blown in will at least partially escape through openings (9) in the planking (7) on the outer layer (3).
14. Method according to any of claims 11 to 13, characterised in that prior to blowing in the insulating layer (4) a covering layer (8) open for diffusion, i.e. preferably a fleece layer, is applied on the planking of the outer layer, and that a plaster base (15) is applied before application of the clay-material layer (5).
15. Method according to any of claims 11 to 14, characterised in that at least part of the insulating layer (4) is poured into the horizontally lying structural element.

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