Fire door

Abstract

 A steel-structured door (1), which comprises a steel door frame (2), a refractory thermal insulation, and a door panel (3) on either face of the door, one of said door panels making up an external side of the door, whereby the door has its refractory thermal insulation comprising a layer (5) composed of a gypsum material in a plane defined by the door's height and width (an XY-plane).

Description

[0001] The invention relates to a steel-structured door, comprising a steel door frame, a refractory thermal insulation, and a door panel on either face, said door panels making up external sides of the door.

[0002] Steel-structured doors are typically used for applications in which the door is employed for constructing a compartment retarding or stopping the spread of fire in a building. Such typical applications include, among others, doors in shopping centers and office buildings between emergency exit staircases and other business premises or other space, doors between parking garages and exits, and so forth. Especially in public premises, the rate of using a door can often be remarkably high, the door being thus subjected to numerous applications of load over the course of a day.

[0003] Usually the in-door fire resistant thermal insulation employed in prior art fire rated steel doors comprises fire protection insulation based on mineral wool, such as PAROC FPS 14, ISOVER PKOL or the like.

[0004] However, there are new European regulations becoming effective in the near future, according to which the temperature rise of available prior art fire doors shall no longer fulfill these new, more stringent regulations. Nevertheless, it could still be possible to meet such regulations with prior art fire door structures, but that would involve a substantial increase in the door thickness from that of currently available fire doors. This, in turn, increases e.g. the weight of doors and thereby hampers the use thereof.

[0005] The construction of a fire door set forth in the present invention provides for a steel-structured fire door, which complies with said new, more stringent regulations and enables its thickness to be substantially maintained within the conventional fire door thickness range.

[0006] The thermal insulation set inside a fire door of the invention comprises an insulation layer made from a gypsum material, the vaporization of crystal water present in said gypsum material in fire situation resisting effectively the transfer of heat through the door.

[0007] In a solution according to the invention, the layer of gypsum material can be made for example by cutting from a ready-to-use board of gypsum material, such as a building board composed of a gypsum material. Alternatively, the layer of gypsum material can be made for example by casting the gypsum material to its position inside the door.

[0008] The solution according to the invention is not limited just to steel-structured fire doors, but it can be used advantageously also in other steel-structured door designs.

[0009] More specifically, the door according to the invention is characterized by what is presented in the characterizing part of claim 1.

[0010] Referring to the specification of this invention, the applied directions relevant to the construction will be as follows. The X-direction represents a longitudinal direction of the construction, hence for example a vertical direction of the door. The Y-direction represents a lateral direction of the doorway opening. Consequently, the XY-plane is substantially the same as a direction of the door plane. The Z-direction is a thickness or depth direction. As this invention is particularly concerned with the thermal engineering aspects of structural elements, the Z-direction is also generally consistent with the temperature gradient direction of an installed structure in the event of a fire.

[0011] The invention will now be described more precisely by way of example with reference to the accompanying figures, in which:

fig. 1 shows schematically a steel-structured fire door in accordance with the invention,

fig. 2 shows schematically the fire door of fig. 1 in a vertically directed cross-section,

fig. 3 shows schematically the fire door of fig. 1 in a laterally directed cross-section, and

fig. 4 shows diagrammatically the results of a fire test performed on a fire door construction of the invention.

[0012] The construction of a fire door 1 shown in fig. 1 comprises a steel door frame 2, a door panel 3 on either face of the door 1, and a refractory thermal insulation set inside the door frame 2 and the door panels 3, said thermal insulation being depicted more precisely in the subsequent figures.

[0013] Figs. 2 and 3 illustrate more accurately the internal fire door construction of the invention in cross-sectional views.

[0014] In a solution of the invention, the refractory thermal insulation set in a space defined by the door frame 2 and the door panels 3 of the door 1 consists, in the illustrated embodiment, of mineral wool layers 4, as well as an unbroken gypsum material layer 5 interposed therebetween.

[0015] The gypsum material layer 5 is positioned in the internal space of a door in such a way that the gypsum material layer has its face in a substantially parallel relationship with the door panels 3 of the door 1. In addition, the gypsum material layer 5 substantially fills the space defined by the door frame in an XY-plane.

[0016] The gypsum material layer 5 is secured in place inside the door 1 by means of brace blocks 6, said brace blocks being attached to the door frame 2 and/or the door panels 3. The brace blocks 6 are preferably made from steel hollow profile.

[0017] In a solution of the invention, the gypsum material layer 5 can be made for example by cutting from a ready-to-use gypsum material board, such as from a building board of gypsum material. Alternatively, the gypsum material layer 5 can be made for example by casting the gypsum material to its position inside the door 1.

[0018] In a solution of the invention, the door frame is preferably made from steel profile, having its interior filled with mineral wool. In addition, the door frame 2 has its steel profile provided with heat discontinuities, said heat discontinuities retarding the propagation of heat in a Z-direction across the door. The door panels 3 are preferably manufactured in steel sheet. Attachment of the door panels 3 to the door frame 2 can be carried out for example by welding, a screw attachment and/or gluing. The useful mineral wool in a solution of the invention is for example PAROC FPS 14, ISOVER PKOL or the like fire resistant mineral wool.

[0019] Fig. 4 shows diagrammatically the results of a fire test performed on a fire door construction of the invention. This particular fire test was conducted in a gas furnace, in which the door construction of the invention had been positioned to close the combustion chamber. In fig. 4, a line A represents, as a function of time, the average temperature rise measured at several measuring points in coincidence with the brace block 6 on the external surface of a door construction according to the invention. A line B represents, as a function of time, the average temperature rise measured at several measuring points in coincidence with the refractory thermal insulation on the external surface of a door construction according to the invention. A line C represents, as a function of time, the average temperature rise measured at several measuring points in coincidence with the door frame 2 on the external surface of a door construction according to the invention.

[0020] It can be seen from the diagram of fig. 4 that the temperature rise in coincidence with the refractory thermal insulation, as represented by the line B, climbs in about 35 minutes to about 100°C, which temperature remains unchanged to the point of about 65 minutes, after which the temperature begins to rise further. Relating to this, it should be noted that the initial temperature of the fire test is the normal room temperature, i.e. about 20°C.

[0021] This substantially flat section of the line B, depicted in fig. 4 at the temperature of about 100° between time points of about 35 minutes and about 65 minutes and thereby representing the temperature of a fire door's external surface in coincidence with the refractory thermal insulation, results from the fact that crystal water, which is contained in the gypsum material layer 5 present in the thermal insulation, is escaping from the gypsum material. This escape of crystal water by evaporation has a cooling effect on the thermal insulation and maintains it at a steady temperature until the evaporation of crystal water from the gypsum material is complete. The relatively steep temperature rise at the time point of about 67 minutes along the line B represents a situation in which all of the crystal water has evaporated from the gypsum material, allowing the gypsum material temperature to rise again.

[0022] It should also be noted in fig. 4 that the criteria defined according to new, more stringent regulations, regarding the rise of temperature in 60 minutes, are fulfilled by a fire door construction according to the invention.

Claims

1. A steel-structured door (1), comprising a steel door frame (2), a refractory thermal insulation, and a door panel (3) on either face, one of said door panels making up an external side of the door, characterized in that the refractory thermal insulation of the door comprises a layer (5) composed of a gypsum material in a plane defined by the door's height and width (an XY-plane).

2. A door according to claim 1, characterized in that the layer (5) composed of a gypsum material is placed in a space defined by the door frame (2).

3. A door according to claim 1 or 2, characterized in that the refractory thermal insulation further comprises mineral wool layers (4) placed on both sides of the layer (5) composed of a gypsum material.

4. A door according to any of claims 1-3, characterized in that the layer (5) composed of a gypsum material is made from a building board of gypsum.

5. A door according to any of claims 1-3, characterized in that the layer (5) composed of a gypsum material is made by casting.

6. A door according to any of claims 1-5, characterized in that the door is a fire door (1).

Drawing