Patent Publication Number: US-2017370097-A1

Title: Facade assembly, building structure and method for mounting the facade assembly

Description:
The invention relates to a facade assembly for a building with at least one facade element, which can be fastened to a wall or a ceiling of the building, and with at least one fire-protection element, which can be mounted between the facade element and the wall. The invention further relates to a building structure using the facade assembly and to a method for mounting such a facade assembly. 
     Curtain facades that consist of individual facade elements, which are fastened to a shell of a building, are frequently used in the building sector. As an example, the shell is manufactured in skeleton form and the facade elements constitute the exterior skin of the building, in which case the facade elements take over the function of a wall construction. The individual facade elements usually have a substructure, for example a framework, by means of which the facade elements are fastened to the shell, in which case the individual facade elements bear only their own weight and have no static functions. These facade elements may take over insulating functions as well as stylistic functions for the exterior skin. 
     On the back side, the facade elements frequently have a cladding, which consists of steel sheet, for example. Joints sealed by insulating material, comprising mineral wool in the prior art, are usually present between the shell and the facade elements, in order to prevent propagation of fire behind the facade elements in the event of fire. These insulating elements are disposed at the height of the inter-story ceilings, so that spreading of the fire from one story to another story is prevented, in which case the fire-protection elements are also able to take over further insulating functions, such as sound protection, for example. 
     In the event of fire, however, the facade elements may expand and become deformed. Especially for facade elements with a sheet-metal element on the back side, large deformations of the sheet-metal elements and thus of the facade elements may occur. These deformations may cause the joint between the wall or the ceiling and the facade element to become so large that the insulating element is no longer able to fill the joint between the facade element and the wall or the ceiling completely and seal it against fire or smoke. 
     From U.S. Pat. No. 7,856,775 B2, it is known to fix an additional mineral-wool block on the steel sheet underneath the insulating element filling the joint. The additional mineral-wool block is intended to close the gap that develops in the event of fire. However, the attachment of the additional mineral-wool block necessitates tasks at ladder height in the floor underneath the insulating element and thus leads to a higher risk of injury as well as additional time requirements. 
     The object of the invention is to provide a facade assembly that permits better sealing of the joint between facade element and wall or ceiling in the event of fire and thus provides better fire protection and can be mounted with little working effort. 
     The object is achieved by providing a facade assembly for a building, with at least one facade element, which can be fastened to a wall or a ceiling of a building, and with at least one fire-protection element, which can be mounted between the facade element and the wall or the ceiling, wherein, according to the invention, the fire-protection element has at least one fire-protection course of an intumescent material. The intumescent material foams up under the effect of heat, and so it is able to fill any joint that develops in the event of fire or that is already present between facade element and wall or ceiling. Thereby reliable protection against propagation of fire and/or smoke is provided. Since the intumescent material has a very small volume in the non-activated condition, it can be used even in very narrow joints present between facade element and wall or ceiling in the regular installation condition. 
     The facade element is known in principle from the prior art. Preferably the facade element is designed as a curtain facade, with a frame construction, preferably of steel or aluminum, an outer covering, which is joined to the frame construction and can be formed from glass, ceramic, metal or natural stone. Cladding, preferably formed from steel sheet, is provided on the back side of the covering, which in the installed condition faces the building. A deadening or insulating layer, for example of mineral wool or foam, can be provided between the exterior covering and the cladding. 
     The fire-protection element may additionally have an insulating layer, especially a mineral-wool insulating layer, particularly preferably a compressed mineral-wool insulating layer. The insulating layer is able to establish sealing of the joint in the regular installation condition, i.e. when the intumescent material has not foamed up, and so the quantity of the intumescent material, i.e. the thickness of the fire-protection course can be reduced. In addition, the insulating layer is able to prevent or reduce penetration of smoke or fire before the intumescent material swells up, so that even better protection against propagation of fire and/or smoke is provided. The insulating layer is preferably designed such that the fire-protection element fills and seals the joint in the regular installation condition. 
     The insulating layer and the fire-protection course can be disposed in any desired manner relative to one another, as long as it is ensured that complete sealing of the joint will be achieved by the intumescent material as it foams up in the event of fire. 
     Preferably the at least one fire-protection course of intumescent material is disposed between the insulating layer and the facade element, i.e. directly on the facade element. In this way, the facade element being deformed and forced away from the wall or the ceiling is sealed against the insulating layer, whereby reliable sealing of the entire joint is achieved. 
     As an example, the fire-protection course may be fastened to the facade element, for which purpose any desired types of chemical or mechanical fastening are possible, for example adhesive bonding or fastening with additional fixation elements such as rivets or screws. 
     According to the invention, it is sufficient that a fire-protection course of an intumescent material be present. In order to permit better sealing of the joint, however, several fire-protection courses of intumescent material may also be provided. As an example, they may be disposed over the entire width of the joint, so that reliable sealing of the joint takes place in the event of fire. Alternatively, however, the fire-protection courses may also be disposed in such a way that they are forced away from one another in the event of fire, whereby even a larger gap can be closed. 
     In addition, it is conceivable that the fire-protection courses are joined flexibly to one another, so that they are movable relative to one another but nevertheless complete sealing of the joint is achieved. In particular, the fire-protection courses can be folded in single, multiple or accordion-like manner, in which case, in the event of fire, they can be forced away from one another due to foaming up and thus can be forced further into a broader joint before they foam up completely. 
     In order to ensure the stability of the fire-protection element with foamed-up fire-protection courses, preferably at least one retaining element is disposed on or in the fire-protection courses, thus imparting a more stable structure to the fire-protection element. In particular, the retaining element may consist of a glass-fiber fabric. This offers the advantage that it is flexible in the non-activated condition of the fire-protection courses, so that flexible joining of the fire-protection courses among one another can also be achieved by the glass-fiber fabric. In the event of fire, or after heating and subsequent cooling, the glass fibers are integrated into the ash crust and form, for the fire-protection courses, a stable retaining structure, which is also able to withstand greater forces, for example when impacted by extinguishing water. 
     In order to prevent damage to the fire-protection element during mounting or during construction of the building, a protective layer that at least partly covers the fire-protection element is optionally provided. As an example, this protective layer may consist of an elastic material such as a curable acrylic dispersion, which is able to even out the temperature-induced expansions of the building or of the facade assembly. 
     Further subject matter of the invention is a building, with at least one wall and/or one inter-story ceiling and at least one facade element, which is fastened to a wall or an inter-story ceiling, wherein a joint is formed between the facade element and the wall or the inter-story ceiling, and with at least one fire-protection element, which is mounted in the region of the joint between the facade element and the wall or the inter-story ceiling, wherein the fire-protection element has at least one fire-protection course of an intumescent material. 
     The facade element and the fire-protection element form the above-described facade assembly to which reference is made. 
     The object is further solved by a method for mounting a facade assembly for a building, with at least one facade element, which is fastened to a wall or a ceiling of the building and is mounted with at least one fire-protection element, which is mounted between the facade element and the wall or the ceiling, wherein the fire-protection element has at least one fire-protection course of an intumescent material, with the following steps:
         Attachment of the facade element to the wall or the inter-story ceiling of the building, wherein a joint is formed between the facade element and the wall or the inter-story ceiling,   Attachment of the fire-protection element to the facade element and/or to the wall or the inter-story ceiling of the building in the region of the joint.       

     Preferably an insulating layer, especially a mineral-wool insulating layer, is additionally mounted as part of the fire-protection element between the facade element and the wall or ceiling, wherein the insulating layer in particular is disposed substantially at the same height as the fire-protection course. Preferably the insulating layer is compressed, so that it is able to expand upon a slight deformation of the facade element and at least partly close the resulting joint. 
     In order to protect the fire-protection element and to seal it against propagation of smoke, a protective layer, especially of an elastic material, is preferably applied, wherein the protective layer covers the fire-protection element at least partly, preferably completely. 
     It is particularly advantageous when all tasks for mounting of the inventive facade assembly can be performed on one building level, especially ground level. 
    
    
     
       Further advantages and features will become obvious from the description hereinafter in conjunction with the attached drawings, wherein: 
         FIG. 1  shows a sectional view through a building with a facade assembly according to the prior art, 
         FIG. 2  shows a sectional view through a building with a first embodiment of a facade assembly according to the invention, 
         FIG. 3  shows a sectional view through a building with a second embodiment of a facade assembly according to the invention, 
         FIG. 4  shows a sectional view through a building with a third embodiment of a facade assembly according to the invention, 
         FIG. 5  shows a detail view of the facade assembly from  FIG. 4 . 
     
    
    
       FIG. 1  shows a section of a building  10 ′ with an inter-story ceiling  12 ′. A facade assembly  14 ′ is hung in curtain style on the exterior of building  10 ′. 
     Facade assembly  14 ′ consists of a facade element  16 ′ as well as a fire-protection element  18 ′, which is disposed in a joint  20 ′ between inter-story ceiling  12 ′ and facade element  16 ′. Fire-protection element  18 ′ consists here of an insulating layer  19 ′, for example of mineral wool. 
     Facade element  16 ′ forms an exterior wall construction or the facade of building  10 ′ and has a substructure, not illustrated in detail here, for example a framework, on which the individual elements of the exterior facade, for example wall elements, windows as well as insulating layers, are retained. The substructure serves for fastening of facade elements  16 ′ on building  10 ′. 
     Facade assembly  14 ′ serves stylistic purposes and/or protection of building  10 ′, wherein exterior side  22 ′ of such a facade element  16 ′ can be configured in any desired manner, especially as a function of viewpoints related to style and/or building physics. As an example, exterior side  22 ′ may have elements of glass, ceramic, metal or other suitable materials. 
     Facade assembly  14 ′ or facade elements  16 ′ bear only their own weight and have no static function for building  10 ′. 
     On back side  24 ′ facing building  10 ′, cladding is provided, which may be part of the interior wall of building  10 ′ and consists here of steel sheet  26 ′. This steel sheet  26 ′ may be part of the substructure or may form merely the interior closure of the facade element. 
     By virtue of fire-protection element  18 ′ provided between inter-story ceiling  12 ′ and facade element  16 ′ penetration of smoke and fire from a region below inter-story ceiling  12 ′ into the region above inter-story ceiling  12 ′ in the event of fire is prevented, and so the propagation of a fire can be prevented or at least slowed. 
     Due to the high temperatures occurring during a fire, however, deformation of facade element  16 ′, especially of steel sheet  26 ′, may occur (see dashed line in  FIG. 1 ). This deformation may cause a gap  30 ′, through which penetration of smoke or fire is possible, to develop between fire-protection element  18 ′ and facade element  16 ′. This means that fire-protection element  18 ′ is not able to fulfill its fire-protection function completely if facade element  16 ′ becomes badly deformed. 
     In order to eliminate this disadvantage, facade assembly  14  shown in  FIG. 2  is provided. The basic design of building  10  with an inter-story ceiling  12  as well as curtain-type facade element  16  corresponds substantially to the design shown in  FIG. 1 . 
     As a supplement to insulating layer  19 , however, fire-protection element  18  additionally has a fire-protection course  32 , which consists of an intumescent material. In the embodiment shown here, fire-protection course  32  is disposed between insulating layer  19  and facade element  16  and in particular is directly fastened on steel sheet  26  of facade element  16 . 
     In the event of fire, the intumescent material of fire-protection course  32  swells up, and so increases its volume. Thereby gap  30  formed between insulating layer  19  and facade element  16  can be closed, so that reliable fire protection is ensured even if facade element  16  becomes deformed. 
     In the embodiment shown here, insulating layer  19  is fastened on inter-story ceiling  12 , whereas fire-protection course  32  is fastened on facade element  16 , in which case the fastening may have the form of a frictional, interlocking and/or substance-to-substance joint, obtained by mechanical or chemical types of fastening, for example. Both insulating layer  19  and fire-protection course  32  are fastened at the height of inter-story ceiling  12 . 
     As soon as facade element  16  becomes deformed due to the intense heat during a fire, gap  30  is developed. Fire-protection course  32 , which is located in this gap  30  due to the positioning on facade element  16 , will be exposed to the heat, and so rapid foaming up of fire-protection course  32  and thus sealing of gap  30  take place. 
     As can be seen in  FIG. 2 , fire-protection course  32  ends flush on its underside with insulating layer  19 , and so is directly exposed to the rising heat in the event of heat generation, so that foaming up of fire-protection course  32  can take place without further delay in the event of heat generation, for example even before a gap  30  is formed. 
     Preferably fire-protection course  32  extends beyond insulating layer  19  or projects out from it, so that even faster activation of the intumescent material can occur. 
     Regardless of this, however, first-protection layer  32  may be positioned in any desired way, as long as foaming-up of the intumescent material is able to close a gap  30  being formed. Alternatively, it is also conceivable, for example, for fire-protection course  32  to be fastened to the underside of insulating layer  19 . 
     According to a further embodiment, fire-protection element  18  consists only of at least one fire-protection course  32  of intumescent material without an additional insulating layer  19  of mineral wool. 
     A second embodiment of an inventive facade assembly  14  is shown in  FIG. 3 . Therein several fire-protection courses  32  spaced apart in vertical direction are provided at the height of inter-story ceiling  12  and are respectively fastened on steel sheet  26  of facade element  16 . They are able to foam up individually, so that, depending on the heat generation and the deformation of facade element  16 , better sealing of gap  30  is possible. 
     In the embodiment shown in  FIG. 4 , two fire-protection courses  32  are disposed parallel to one another and are flexibly joined to one another along an edge  34 . In the event of fire, the expanding intumescent material forces fire-protection course  32 , which is spaced apart from steel sheet  26 , away in clockwise direction around edge  34  from fire-protection course  32  bearing on steel sheet  26 , so that fire-protection courses  32  spaced apart from steel sheet  26  already penetrate further into gap  30  before they foam up completely. In this way a larger gap  30  can be closed during the subsequent foaming-up of the intumescent material. 
     As can be seen in  FIG. 5 , fire-protection courses  32  in this embodiment are joined to one another by a retaining element  36 . As an example, retaining element  36  consists of a glass-fiber fabric, which has high flexibility. In the event of fire, the glass-fiber fabric becomes heated and hardens during the subsequent cooling, so that a stable stiffening structure is formed for fire-protection element  18 , with the result that fire-protection courses  32  are reliably fixed and gap  30  is closed. Thus fire-protection element  18  is also able, for example, to withstand the impact of extinguishing water. 
     As can be seen in  FIG. 5 , retaining element  36  extends into fire-protection courses  32 , so that a stable frictional and interlocking bond is formed with retaining element  36 . 
     Alternatively, it is also conceivable for retaining element  36  to be adhesively bonded to the exterior of fire-protection courses  32 , thus forming additional protection for fire-protection courses  32 . 
     As can be further seen in  FIG. 4 , an elastic protective layer  38  is provided that covers the entire fire-protection element  18  externally, so that fire-protection element  18  is reliably protected against mechanical stress and strain.