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(11) | EP 2 453 098 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Access door and access door frame |
| (57) The invention relates to an access door (40), its frame (20) and a combination thereof.
The heat insulation of said access door (40) is composed of at least two different
insulation materials (32, 33), and the frame (20) is perforated in order to reduce
thermal conductivity.
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[0001] The invention relates to an access door and its frame. More precisely, the invention covers the scope defined in the independent claims.
[0002] An access door is installed in a wall or ceiling, and as for fire resistance and thermal conductivity, it must fulfill the fire safety requirements effective at each point of time. Access doors are used in buildings for maintenance, locking and other such purposes. An access door comprises a mounting rack that is attached in a wall or ceiling, and a lid element hinged in the mounting rack. The lid element and the mounting rack are conventionally metallic in structure, and the lid element also includes an insulation material layer. The conventional shape of the access door is either a square or a rectangle.
[0003] With access doors, it is a continuous objective to achieve an improved fire safety without remarkably increasing the door thickness. At the same time, the thermal conductivity of the access door frame, and the reducing of said conductivity, becomes all the more important in the big picture.
[0004] The objective of the present invention is to introduce a new access door with frame, which fulfill all the more stricter requirements for fire resistance and thermal conductivity. Said objective is achieved according to the characterizing features of the independent claims.
[0005] In the specification below, the invention is described in more detail with reference to the appended drawings, where:
Figure 1 is a side-view illustration of a prior art access door frame,
Figure 2 is a side-view illustration of an access door frame according to a preferred embodiment of the invention,
Figure 3 is a cross-sectional illustration of an access door lid element with frame according to an embodiment of the invention, and
Figure 4 is a cross-sectional illustration of an access door lid element with frame according to an embodiment of the invention, as mounted on a wall or ceiling.
[0006] Figure 1 illustrates part of an access door frame 1 according to the prior art. The center part of the frame 1 is completely cut off, apart from those points of the frame where the frame is attached to a wall or ceiling, and the frame corners 2, so that apertures 3 are formed in the frame. Said fastening points 4 are located at the center of the frame sides, so that each frame side includes two large holes 2. The purpose of the performed cut-offs is to reduce heat transfer through the frame 1. However, as the center part is completely removed by forming apertures 3, heat is explicitly conducted through the uniform areas of the frame, said areas being located at the frame corners 2 and the fastening points. With this kind of arrangement, the temperature distribution of the frame 1 becomes extremely uneven.
[0007] Figure 2 illustrates a preferred embodiment of an access door frame 20 according to the invention. In this arrangement, the frame 20 is perforated, so that in the perforated area, heat has partial access through the frame. This is facilitated by preparing the perforation in two or more rows, in which case the holes 21 of separate rows are centered, so that the passage of the heat transferred through the frame 20 becomes longer than the direct measure through the frame in the direction of the wall thickness. Thus heat is distributed more evenly through the frame 20. At the same time, the frame 20 includes more material, and it is capable of binding more heat than the arrangement according to the prior art. There is no perforation at the fastening points 11, but the perforation arranged in several rows can, according to Figure 2, also extend to the fastening area for one or more rows. This is not possible in the prior art arrangement. This in part slows down heat transfer at the fastening point. As for the corners 23, the frame according to the invention corresponds to the prior art arrangement. In shape the holes 21 illustrated in Figure 2 are rectangular, but for a person skilled in the art, it is obvious that a similar effect for thermal conductivity is also achieved by holes with another shape. The essential point is that in a perforated area, the passage of heat through the frame 20 is longer than in a non-perforated area. In a perforated area, the number of hole rows is anything up from two, and in each row, the number of holes 21 is anything up from one. Typically the number of hole rows is 3-5, and the number of holes 21 in each row is 2-10 by average.
[0008] Access doors are typically manufactured for square apertures with the size of 20x20, 30x30, 40x40, 50×50 or 60x60 cm. When necessary, it is also naturally possible to manufacture different sizes of doors, for instance with a rectangular shape.
[0009] Figure 3 illustrates in partial cross-section a preferred embodiment of an access door lid element 30 according to the invention. The access door lid element 30 is attached to the access door frame 20. The access door lid element 30 comprises a metallic surface plate 31 and insulation materials 32 and 33. In prior art arrangements, only one insulation material has been used together with a metallic surface plate 31. Among said insulators, there are typically included fireproof mineral wools and fireproof plates. One solution applied in prior art access doors is vermiculite plate.
[0010] In the embodiment of Figure 3, there is used one gypsum board 32 and two fireproof mineral wool plates 33 (for example Isover Ultimate KPV 100). For a person skilled in the art, it is obvious that the number and thickness of the wool plates 33 is chosen among the readily available alternatives according to the thickness of the access door. Thus it is possible to use one or several wool plates 33 with identical or different thicknesses. The essential point is that two different materials are used. In this embodiment, they are gypsum board 32 and fireproof wool 33. Instead of fireproof wool 33, some other known fireproof material can be used with the gypsum board 32. The use of a gypsum board 32 in the access door structure is advantageous for example owing to the moisture released thereby as it is warmed up, in which case it, together with other fireproof material, very effectively prevents heat from being conducted through the access door. Gypsum board 32 can be used in the structure in a way illustrated in Figure 3, or so that the gypsum board is installed on the other side of the other fireproof material 33. Gypsum boards 32 can also be installed on both sides of the other fireproof material 33.
[0011] Typically the thickness of the access door corresponds to the material thickness of the mounting location (wall/ceiling). By employing an arrangement according to the invention, with two different materials in the door structure the door thickness is reduced, so that the usability (ease of opening) is improved. For instance, it is possible to manufacture a door comprising two 6.5 mm thick gypsum boards, with a 20 mm thick wool plate 33 in between. In that case the door thickness remains below 40 mm.
[0012] Figure 3 also illustrates a device 34 to be installed in the access door frame 20, such as a tack, screw, peg or the like, which supports the access door surface plate 31 so that it is not buckled owing to the thermal stress.
[0013] Figure 4 illustrates an arrangement according to the invention of the access door 40 and its frame 20, as mounted on a wall or ceiling 41. In between the access door 40 and the frame 20, as well as in between the access door and the wall/ceiling 41, there are installed sealings 42 for preventing a direct heat transfer through said gaps. The employed sealing material can be some known sealing. The sealing materials used in access doors 40 are strongly expansive owing to the effect of heat. Their volume may increase up to even 20-fold. When employing a frame 20 for an access door 40, the sealing 42 is expanded, so that it penetrates through the frame perforation and realizes a double sealing, as the sealing material protrudes to both sides of the frame and gets into contact with the door structures as well. Advantageously the sealing can be realized in a way described in Figure 4, so that the sealing strip 42 is mounted in between the frame 20 and the lid element 30 of the access door 40, as well as between the frame and the wall/ceiling 41.
1. An access door (40) to be mounted on a wall/ceiling (41), comprising a metallic surface
material (31) and heat insulation, characterized in that the heat insulation of the access door (40) is composed of at least two different
insulation materials (32, 33).
2. An access door (40) according to claim 1, characterized in that the heat insulation employed in the access door (40) includes at least one gypsum
board (32) and at least one plate (33) made of some other fireproof material.
3. An access door (40) according to claim 2, characterized in that the gypsum board (32) can be mounted on either side of the other fireproof material
(33).
4. An access door (40) according to claim 2, characterized in that the heat insulation of the access door (40) is composed of two gypsum boards (32)
and other fireproof material (33) placed in between said boards.
5. An access door (40) according to any of the claims 2-4, characterized in that the fireproof material used in addition to the gypsum board (32) is vermiculite,
mineral wool or some other corresponding fireproof material.
6. A frame (20) for an access door (40), made of metal, characterized in that the frame (20) is provided with two or several rows of holes (21) placed in the wall
depth direction in that area of the frame (20) that corresponds to the thickness of the wall/ceiling (41),
said holes (21) being aligned so that the uniform metal surface in the perforated
area forms a longer length of passage from one surface of the wall/ceiling (41) to
the other than the thickness of the wall/ceiling (41).
7. A frame (20) according to claim 6, characterized in that the rows of holes do not extend as far as the frame corners (23).
8. A combination of access door (40) and access door frame (20), characterized in that the combination includes at least one of the arrangements according to claims 1 and
6.
9. A combination according to claim 8, characterized in that the access door frame (20) includes a tack, screw, peg or other such element (34)
to be installed on the side of the access door (40), which element supports and protects
the metal surface (31) of the access door from being buckled.