Fastening structure of fire-resistant covering material in exterior wall panels

Abstract

To provide a fastening structure for a fire-resistant covering material, which is inexpensive and excellent in workability, can effectively prevent hot air flowing into a joint from the outside from flowing over the stiffener into the ventilation space while securing an appropriate ventilation space between stiffeners installed near both side edges on the back side of a concrete panel. [Solution] A felt mat-like fire-resistant covering material 70 that covers the back surface of the concrete panel and the protruding portions of both stiffeners from the indoor side is fastened to the back surface 2a of the concrete panel 2 from the indoor side with fasteners 9 consisting of concrete screws 91 and washers 92. The fasteners 9 are arranged in a vertical row at a predetermined pitch so as to straddle the stiffeners 30, on the edge side of each stiffener 30 and on the central side of each stiffener 30. The fasteners 9 on the edge side and the fasteners 9 on the central side have individual heights that differ from each other, so that at least one fastener 9 on either side is arranged within the adjacent vertical spacing of the fasteners 9 on the other side.

Description

[Technical Field]

[0001] The invention disclosed in this application relates to a fastening structure for a fire-resistant covering material in an exterior wall panel in which a fiber-based fire-resistant covering material is laminated on the back surface of a plate-shaped concrete panel. [Background technology]

[0002] In order to improve the fire resistance of the exterior wall portions of buildings that use plate-shaped concrete panels as exterior wall materials, the applicant invented an exterior wall panel in which a fibrous fire-resistant covering material made of rock wool or glass wool is laminated onto the back surface of the concrete panel, and disclosed this in Patent Document 1.

[0003] 1 to 4 show an embodiment in which the exterior wall panel described in the document is used as a curtain wall material for a steel-frame building. The example exterior wall panel 1 includes a plate-shaped concrete panel 2, a hat steel beam 3 embedded in the concrete panel 2 with a portion exposed on the indoor side, an insert nut 4 placed in an appropriate position in a groove of the hat steel beam 3 and embedded in the concrete panel 2, a locking metal fitting 5 bolted to the insert nut 4 from the indoor side of the hat steel beam 3 to lock the exterior wall panel 1 to a steel beam X, a fire-resistant covering material 7 covering the back surface 2a of the concrete panel 2 and the exposed portion of the hat steel beam 3, and a fixing metal fitting 8 fixing the fire-resistant covering material 7 to the hat steel beam 3.

[0004] The hat steel 3 is a stiffening material for reinforcing the rigidity of the concrete panel 2. The hat steel 3 is arranged near both left and right edge portions of one concrete panel 2, extending vertically across the entire height of the concrete panel 2. The horizontal distance from both left and right edge portions of the concrete panel 2 to the core of each hat steel 3 is set to approximately 100 mm to 150 mm. The hat steel 3 has a bottom plate 31 and a pair of left and right side plates 32, which form a U-shaped groove opening toward the exterior, and each of the side plates 32 has a slat 33 extending from the exterior-facing edges of the side plates 32 to the outside of the groove. The slat 33 and the middle portions of the side plates 32 are embedded in the concrete panel, and the bottom plate 31 protrudes approximately 15 mm to 18 mm from the back surface 2a of the concrete panel 2 toward the interior.

[0005] After fastening the locking fittings 5 ​​to the hat steel 3 with bolts 6, the fire-resistant covering material 7 is fastened to the bottom plate 31 of the hat steel 3 so as to cover almost the entire back surface of the exterior wall panel 1 (the areas colored light gray in Figure 2) except for a portion of the upper and lower ends. The fire-resistant covering material 7 is made of rock wool, which has excellent fire resistance, or glass wool, which has excellent thermal insulation properties, and is formed into a felt mat with moderate flexibility. The thickness of the fire-resistant covering material 7 varies depending on the required performance and the area where it is used. For example, to ensure one-hour fire resistance, a 20 mm thick layer of rock wool can be layered on a 55 mm thick concrete panel 2.

[0006] The fixing bracket 8 is used to secure the fire-resistant covering material 7 to the bottom plate 31 from the indoor side. The fixing bracket 8 shown in FIG. 4 is composed of a clamping bracket 81, which is wider than the bottom plate 31 of the hat steel 3, and a screw 82 for securing the clamping bracket 81 to the bottom plate 31. The clamping bracket 81 includes a rectangular plate portion 81a in front view and two trapezoidal clamping portions 81c in side view that protrude perpendicularly from both ends of the longitudinal edge 81b of the plate portion 81a and hold down the fire-resistant covering material 7. The distance C between the clamping portions 81c is set so that the hat steel 3 exposed indoors can be covered with the fire-resistant covering material 7. A screw hole 81d is formed in the center of the plate portion 81a, and four openings 81e are formed around it. These openings 81e serve to reduce heat buildup in the clamping bracket 81 during a fire.

[0007] By using such an exterior wall panel 1 as an exterior wall material, it is possible to improve the fire resistance of the exterior wall portion using a simple construction method while reducing the thickness and weight of the concrete panel 2. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2022-115268 Summary of the Invention [Problem to be solved by the invention]

[0009] In the conventional exterior wall panel 1, the concrete panel 2 and the fire-resistant covering material 7 are not in close contact over the entire surface, but are configured so that a moderate gap is created between them, which can be used as a ventilation space within the wall. In a normal single-panel fire-resistant wall, to prevent flames and heat from being transmitted from lower floors to upper floors, it is necessary to separate the space between the beams and the exterior wall material between floors with mortar or the like, and to install ventilation louvers in the exterior wall material of each floor for ventilation within the wall. However, by connecting the above-mentioned ventilation spaces between the upper and lower floors, it is possible to omit the ventilation louvers that would normally be installed in the exterior walls of the lower floors.

[0010] However, improving the air permeability between the concrete panels 2 and the fire-resistant covering material 7 also makes it easier for hot air to flow in during a fire, so measures to prevent this are necessary. In particular, the joints where the concrete panels 2 are adjacent have lower heat-shielding performance than the center parts of the concrete panels 2, making them weak points through which hot air from the outside can easily flow in. If the hot air that flows into the back side of the concrete panel 2 through these joints flows around the indoor side of the stiffeners (hat-shaped steel 3) and into the center of the concrete panel 2 (the ventilation space between the left and right stiffeners), the hot air will rapidly rise to the upper floors due to the chimney effect, and there is a risk that the entire exterior wall will become very hot in a short period of time.

[0011] One way to ensure an adequate ventilation space between the left and right stiffeners while preventing hot air flowing in through the joints from overflowing the stiffeners and into the central ventilation space is to narrow the spacing between the aforementioned fastening metal fittings 8. However, increasing the number of fastening metal fittings 8 with special shapes as shown in the example would undesirably increase material costs and installation labor.

[0012] The invention disclosed in this application was conceived in light of the above circumstances, and provides a fastening structure for fire-resistant covering material that is cheaper and easier to install than conventional structures, and that can effectively prevent hot air that has flowed into the joint from the outside from passing over the stiffeners and into the ventilation space while ensuring an appropriate ventilation space between the left and right stiffeners attached to the exterior wall panel. [Means for solving the problem]

[0013] In order to achieve the above-mentioned object, the invention disclosed in this application provides a fastening structure for a fire-resistant covering material in an exterior wall panel, which comprises a concrete panel erected on the exterior wall of a building, a pair of left and right stiffeners embedded in the vicinity of both side edges of the concrete panel so that a portion of the stiffeners protrudes indoors beyond the rear surface of the concrete panel and extends vertically over the entire height of the concrete panel, and a felt mat-like fire-resistant covering material covering the rear surface of the concrete panel and the protruding portions of both stiffeners from the indoor side, and which is a fastening structure for a fire-resistant covering material in which the fire-resistant covering material is fastened to the rear surface of the concrete panel from the indoor side with fasteners. Therefore, the fire-resistant covering material, which is layered over almost the entire surface of the concrete panel except for specified areas near the upper and lower edges, is fastened to the concrete panel so as to straddle the stiffeners by fasteners arranged in a vertical row at specified intervals on the edge side of the concrete panel relative to each stiffener, and fasteners arranged in a vertical row at specified intervals on the center side of the concrete panel relative to each stiffener, the fasteners fastened to the edge side and the fasteners fastened to the center side having different individual heights, and at least one fastener on either side is arranged within the adjacent vertical space between the fasteners on the other side.This is a basic configuration.

[0014] In the fastening structure of the fire-resistant covering material in the exterior wall panel relating to the basic configuration described above, it is more preferable that the back surface of the concrete panel is covered with one or more pieces of the fire-resistant covering material cut to a size that spans the entire width of the concrete panel.

[0015] Furthermore, the fastening structure of the fire-resistant covering material in the exterior wall panel of the invention disclosed in this application employs an additional configuration in which, where two concrete panels are adjacent to each other across a joint, a fire-resistant covering material for the back of the joint is layered between the stiffeners of both adjacent concrete panels.

[0016] In this case, it is more preferable that the fire-resistant covering material for the back of the joint and the fire-resistant covering material covering substantially the entire surface of the concrete panel are overlapped so that their respective joint positions do not coincide with each other. [Effects of the Invention]

[0017] The fastening structure for the fire-resistant covering material in the exterior wall panels configured as described above can be installed using an inexpensive and simple construction method that ensures an appropriate ventilation space between the left and right stiffeners, while effectively preventing hot air that has flowed from the outdoors into the joints between adjacent exterior wall panels from passing over the stiffeners and flowing into the ventilation space. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a partially omitted vertical cross-sectional view showing an exterior wall panel described in Patent Document 1, which is background art of the invention disclosed in the present application, installed on a steel-framed building. [Figure 2] FIG. 2 is an elevation view of the exterior wall panel of FIG. 1 as seen from the back side (indoor side). [Figure 3] 3 is a partially omitted cross-sectional view showing an enlarged view of a portion near a stiffener in the cross section of line AA in FIG. 2. FIG. [Figure 4] FIG. 1 is a perspective view of a fixing bracket used in the exterior wall panel described in Patent Document 1. [Figure 5] 1 is an elevation view showing the arrangement of fasteners of an exterior wall panel according to an embodiment of the invention disclosed in the present application, viewed from the back side (indoor side). FIG. [Figure 6] 6 is a partially enlarged cross-sectional view showing the state in which the fire-resistant covering material is laid over the area near the joint in the cross section of the exterior wall panel taken along line BB in FIG. 5. FIG. [Figure 7] FIG. 10 is an elevation view showing another example of the arrangement of fasteners. [Figure 8] FIG. 10 is a partially enlarged cross-sectional view showing another example of the state in which the fire-resistant covering material is laid in the vicinity of the joint. [Figure 9] FIG. 10 is a partially enlarged cross-sectional view showing yet another example of the state in which the fire-resistant coating material is laid in the vicinity of the joint. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, preferred embodiments of the invention disclosed in this application will be described with reference to the drawings. In the embodiments described below, components that are substantially the same as those in the conventional exterior wall panel 1 shown in Figures 1 to 4 are designated by the same reference numerals, and their description will be simplified.

[0020] Figures 5 and 6 show an example of an exterior wall panel 10 to which the invention disclosed in the present application is applied. Similar to the exterior wall panel 1 described in Patent Document 1 and shown in Figures 1 to 4, this exterior wall panel 10 includes a plate-shaped concrete panel 2, a stiffener 30 embedded in the concrete panel 2 with a portion exposed to the interior side, a fastening metal fitting 5 connected to the stiffener 30, and a fire-resistant covering material 70 that covers the back surface 2a of the concrete panel 2 and the exposed portion of the stiffener 30.

[0021] For the stiffener 30, a hat-shaped steel beam 3 similar to that used in the exterior wall panel 1 described in Patent Document 1 can be used, but in the illustrated embodiment, a channel steel beam with a U-shaped cross section is used. The channel steel beam is integrated with the concrete panel 2 by welding a pair of left and right side plates 32 to a mesh panel 34 placed inside the concrete panel 2, and by causing the bottom plate 31 to protrude toward the interior of the building beyond the back surface 2a of the concrete panel 2. Locking fittings 5 ​​are attached to appropriate locations near the upper and lower ends of the stiffener 30, and the locking fittings 5 ​​are locked to exterior wall mounting rails joined to the steel beam X (see Figure 1).

[0022] The fire-resistant covering material 70 may be a fiber-based covering material that is the same as or similar to the fire-resistant covering material 7 used in the exterior wall panel 1 described in Patent Document 1. The fire-resistant covering material 70 in this exemplary embodiment is assumed to be a long roll-type material in which rock wool is formed into a felt mat with a high-density nonwoven fabric attached to one side. The fire-resistant covering material 70 is cut from the long roll so that one sheet spans the entire width of the concrete panel 2, and the cut length is then overlapped on the back surface 2a of the concrete panel 2 in the width direction of the concrete panel 2. In other words, it is generally desirable not to patch the fire-resistant covering material 70 in the width direction of the concrete panel 2.

[0023] Then, multiple pieces of fire-resistant covering material 70 are patched together without gaps along the height direction of the concrete panel 2 over substantially the entire surface (between the upper and lower fastening fittings 5 ​​in the illustrated embodiment: the lightly shaded area in Figure 5) except for predetermined areas near the upper and lower edges of the concrete panel 2. If the total height of the concrete panel 2 is around 3m and the roll width (working width) of the fire-resistant covering material 70 is 900mm to 1000mm, three pieces of fire-resistant covering material 70 will be patched together in the height direction on one concrete panel 2. The upper and lower edges of the patched fire-resistant covering materials 70 are joined together, for example, by tape adhesion or the like.

[0024] In addition, if the roll width of the fire-resistant covering material 70 is larger than the width of the concrete panel 2, the fire-resistant covering material 70 can be cut to fit the height dimension of the concrete panel 2, and one piece of the fire-resistant covering material 70 can cover almost the entire back surface 2a of the concrete panel 2.

[0025] In this exterior wall panel 10, the fire-resistant covering material 70 is not fixed to the stiffener 30 with the fixing bracket 8 as shown in Fig. 4, but is fastened to the back surface 2a of the concrete panel 2 using a fastener 9 consisting of, for example, a concrete screw 91 and a washer 92. The key feature of the invention disclosed in this application lies in the arrangement of the fastener 9. The fastening positions of the fastener 9 are indicated by black circles in Fig. 5.

[0026] The fire-resistant covering material 70 is fastened to the concrete panel 2 so as to straddle the stiffener 30 by a plurality of fasteners 9 arranged in a vertical row at predetermined intervals outside the stiffener 30 (towards the edge of the concrete panel 2) and a plurality of fasteners 9 arranged in a vertical row at predetermined intervals inside the stiffener 30 (towards the center of the concrete panel 2). In other words, the fasteners 9 are arranged in a vertical row on both the left and right sides of the stiffener 30, along the length of the stiffener 30. A feature of the present invention is that the fasteners 9 fastened to the edge sides of the concrete panel 2 and the fasteners 9 fastened to the center of the concrete panel 2 are arranged at different heights on the left and right, in a zigzag or staggered pattern.

[0027] When the step between the back surface 2a of the concrete panel 2 and the bottom plate 31 of the stiffener 30 is approximately 15 to 18 mm, and the horizontal distance from the edge of the concrete panel 2 to the core of the stiffener 30 is approximately 100 to 150 mm, it is preferable that the distance D1 (see FIG. 6) between the arrangement line of the fasteners 9 and the side plate 32 of the stiffener 30 be set to approximately 30 to 60 mm on the edge side of the concrete panel 2 relative to the stiffener 30. In the illustrated embodiment, each fire-resistant covering material 70 is fastened at three locations: one near the top edge, one near the bottom edge, and one intermediate location between them. In this case, the vertical spacing P between adjacent fasteners 9 is approximately 400 to 450 mm.

[0028] On the more central side of the concrete panel 2 than the stiffeners 30, it is preferable that the distance D2 (see FIG. 6) between the arrangement line of the fasteners 9 and the stiffeners 30 is set to be approximately the same as or slightly larger than the distance D1 between the arrangement line of the fasteners 9 on the edge side and the stiffeners 30. In the illustrated embodiment, the fasteners 9 on the more central side than the stiffeners 30 are fastened at two positions at a height intermediate between the three fastening positions of the fasteners 9 on the edge side. In this case, the vertical spacing Q between adjacent fasteners 9 is approximately 400 mm to 450 mm, the same as P, and the distance R from that position to the upper or lower edge of the fire-resistant covering material 70 is approximately 230 mm to 300 mm.

[0029] Basically, no further fastening is performed further toward the center of the concrete panel 2. As a result, between the fasteners 9 arranged in a row toward the center of the left and right stiffeners 30, a ventilation space S (see FIG. 6) is formed, which allows the fire-resistant covering material 70 to be appropriately spaced from the back surface 2a of the concrete panel 2. Note that to make it easier to form the ventilation space S, an appropriate spacer may be inserted between the back surface 2a of the concrete panel 2 near the center and the fire-resistant covering material 70.

[0030] By adopting such an arrangement of the fasteners 9, lifting of the fire-resistant covering material 70 on both the left and right sides of the stiffener 30 is suppressed approximately uniformly along the length of the stiffener 30, improving the adhesion of the fire-resistant covering material 70 to the concrete panel 2 and the stiffener 30. As a result, hot air that flows into the back surface 2a of the concrete panel 2 from the joints where the concrete panels 2 are adjacent is blocked by the stiffener 30, and does not flow into the ventilation space S formed more toward the center than the stiffener 30.

[0031] Increasing the number of fastening devices 9 by further narrowing the vertical spacing between adjacent fastening devices 9 or aligning the heights of the fastening devices on the edge and center sides improves the adhesion of the fire-resistant covering material 70 in the areas spanning the stiffeners 30. However, increasing the number of fastening devices 9 also increases the amount of work required for installation. Therefore, by arranging the fastening devices 9 in a zigzag or staggered pattern on the left and right sides of the stiffeners 30, as in the illustrated embodiment, it is possible to minimize the number of fastening devices 9 and significantly reduce the amount of work required for installation while still ensuring a practically sufficient level of heat-shielding effect.

[0032] FIG. 7 shows another example of the arrangement of fastening devices 9. The arrangement shown in FIG. 5 is the same as that shown in FIG. 5 on the edge side of the concrete panel 2 relative to the stiffener 30, with the vertical spacing P between adjacent fastening devices 9 being approximately 400 mm to 450 mm. On the other hand, closer to the center of the concrete panel 2 relative to the stiffener 30, the fastening devices 9 are arranged in four locations, dividing the height of each fire-resistant covering material 70 into five equal parts. In this case, the vertical spacing T between adjacent fastening devices 9 at the center is approximately 180 mm to 200 mm, meaning that two central fastening devices 9 are arranged within each vertical spacing between adjacent fastening devices 9 at the edge side. In this way, the spacing between adjacent fastening devices 9 arranged closer to the edge of the concrete panel 2 relative to the stiffener 30 may be different from the spacing between adjacent fastening devices 9 arranged closer to the center of the concrete panel 2 relative to the stiffener 30, and the spacing relationship between the fastening devices may even be reversed. Furthermore, it is more preferable to fasten the fire-resistant covering material 70 at points including near the corners of the upper edge and near the corners of the lower edge on the edge side of the concrete panel 2, as this makes it less likely that the corners of the fire-resistant covering material 70 will curl or lift up.

[0033] In the fastening structure for fire-resistant covering material disclosed herein, the multiple fasteners 9 fastened in a vertical row on each of the left and right sides of the stiffener 30 are arranged in a "zigzag or staggered" configuration with different heights on the left and right sides. This configuration also encompasses a configuration in which, as shown in FIG. 7 , the fasteners 9 on either side of the left and right rows are arranged in at least one location within the vertical spacing of the fasteners 9 on the other side. Practically, one to three locations is preferable for balance. In this case, the fasteners 9 on one side and the other side are not fixed to the entire stiffener 30. For example, the vertical spacing and height relationship between the fasteners 9 on the left and right sides may be reversed at a midpoint in the longitudinal direction of the stiffener 30, as in the upper and lower joints of the fire-resistant covering material 70 in the configurations shown in FIGS. 5 and 7 . Furthermore, the arrangement of the fasteners 9 may differ between the left and right edges of one concrete panel 2, or between the edges of adjacent left and right concrete panels across a joint.

[0034] Furthermore, the fastening structure of the fire-resistant covering material disclosed in the present application employs a configuration in which a fire-resistant covering material 71 for the back of the joint is laid over and overlapped between the stiffeners 30 of both adjacent concrete panels 2 across the joint M, in order to reliably prevent the inflow of hot air through the joints where the concrete panels 2 are adjacent. The fire-resistant covering material 71 for the back of the joint can be of the same quality as the fire-resistant covering material 70 described above, which covers almost the entire back surface 2a of the concrete panel 2, but it is preferable to use a slightly thinner material (approximately 20 mm) so that it can easily fit into the recess behind the joint surrounded by the step between the concrete panel 2 and the stiffener 30.

[0035] In the embodiment shown in FIG. 6 , for each of two adjacent concrete panels 2, a fire-resistant covering material 71 for the back of the joint is laid on the edge of the concrete panel 2 closer to the stiffener 30 than the stiffener 30. The fire-resistant covering material 71 is cut to a width that extends to the center of the joint M and is temporarily fixed in place in advance using adhesive or double-sided tape. When the concrete panels 2 are installed adjacent to each other with the joint M in between, the side edges of the left and right fire-resistant covering materials 71 for the back of the joint butt together along the joint M, sealing the back of the joint. A fire-resistant covering material 70 that covers substantially the entire surface of the concrete panel 2 is laid on the interior side of the fire-resistant covering material 70, and the two layers are fastened together using fasteners 9. At this time, it is desirable to offset the joint position of the fire-resistant covering material 70 that covers substantially the entire surface of the concrete panel 2 (the position where the side edges butt together) from the joint position of the fire-resistant covering material 71 for the back of the joint (same as above) so that they do not coincide with each other.

[0036] Similarly, when multiple pieces of fire-resistant covering material 71 for the back of the joints are patched along the height direction of the concrete panel 2, it is desirable to align them vertically so that their patching positions do not coincide with the patching positions of the fire-resistant covering material 70 that covers almost the entire surface of the concrete panel 2. By taking these considerations into account, the effect of preventing hot air from entering through the joints M can be further improved.

[0037] As shown in Figure 8, the fire-resistant covering material 71 for the back of the joint may be cut to a width that matches the spacing between the stiffeners 30 of two adjacent concrete panels 2, and may be stretched across the joint M to seamlessly cover the space between both stiffeners 30.

[0038] 9 , a fire-resistant covering material 70 cut to a width sufficiently larger than the distance between the stiffeners 30 of two adjacent concrete panels 2 can be prepared and overlapped on a joint-back fire-resistant covering material 71 so as to straddle both stiffeners 30, thereby preventing the fire-resistant covering material 70 from being patched near the joint M. This fire-resistant covering material 70 may extend across the width of the concrete panel 2 to an extent not shown in the figure. However, in the illustrated embodiment, another fire-resistant covering material 72 covering the central side of the concrete panel 2 is fastened with fasteners 9 near the edge of the fire-resistant covering material 70 straddling the stiffeners 30, closer to the center of the concrete panel 2 than each stiffener 30. In this embodiment, a ventilation space S is formed between the fire-resistant covering material 72 overlapped at the center and the back surface 2a of the concrete panel 2. For example, even if the width of the concrete panel 2 is large, the fire-resistant covering materials 70, 72 may be patched together in the middle of the width direction, and the invention disclosed in this application also encompasses such a configuration.

[0039] The fastener 9 is not limited to the combination of the concrete screw 91 and washer 92 shown in the example. For example, a fastener configured as follows can be used: a push-pin-shaped inserting member having a flat base of an appropriate shape and a puncture pin protruding from the center perpendicular to the surface of the base; the base is attached to a predetermined position on the concrete panel; the fire-resistant covering 70 is pressed against the puncture pin protruding toward the interior; and a retaining cap that also protects the tip of the puncture pin that penetrates the fire-resistant covering is fitted over the puncture pin. Like the fastener 9 consisting of the combination of the concrete screw 91 and washer 92, this type of fastener is also extremely inexpensive and easy to use.

[0040] The fastening structure for the fire-resistant covering material in the exterior wall panels described above is a labor-saving construction method that uses simple fastening tools, and while ensuring an appropriate ventilation space between the left and right stiffeners, it is possible to effectively prevent hot air that has flowed from the outdoors into the joints between adjacent exterior wall panels from passing over the stiffeners and flowing into the ventilation space.

[0041] The technical scope of the invention disclosed herein should not be construed as being limited by the exemplified embodiments, but should be construed conceptually based on the claims. The names of elements used in the claims and the specification are for convenience in making the invention easier to understand, and the names do not unnecessarily limit the concepts or properties of the elements. When implementing the invention disclosed herein, the detailed shape, dimensions, structure, materials, quantity, connection form with other elements, relative positional relationship, etc. of elements not specifically specified in the claims may be appropriately modified within the scope of utilizing an operating principle substantially equivalent to the exemplified embodiments or within the scope of obtaining effects substantially equivalent to or greater than those of the exemplified embodiments. [Explanation of symbols]

[0042] 10 Exterior wall panels 2. Concrete panels 2a back side 30 Stiffener 31 Bottom plate 32 Side panel 5 Locking hardware 70 Fireproof cladding 71 Fire-resistant coating material for joint lining 9 Fasteners 91 Concrete screws 92 Washer M joint S Ventilation space

Claims

1. Concrete panels installed on the exterior walls of the building, a pair of left and right stiffeners embedded in the vicinity of both side edges of the concrete panel so that a portion of the stiffener protrudes indoors beyond the rear surface of the concrete panel and extends vertically over the entire height of the concrete panel; a felt mat-like fireproof covering material that covers the rear surface of the concrete panel and the protruding portions of both stiffeners from the indoor side; In an exterior wall panel comprising: A fastening structure for a fire-resistant covering material in which the fire-resistant covering material is fastened to the back surface of the concrete panel from the indoor side by a fastener, The fire-resistant covering material is superimposed on substantially the entire surface of the concrete panel except for predetermined ranges near the upper and lower edges thereof, and is fastened to the concrete panel so as to straddle the stiffeners by the fasteners arranged in a vertical row at predetermined intervals on the edge side of the concrete panel relative to each stiffener, and the fasteners arranged in a vertical row at predetermined intervals on the center side of the concrete panel relative to each stiffener, The fastening tools attached to the edge side and the fastening tools attached to the center side are different in height from each other, and at least one fastening tool on one side is disposed within an adjacent interval in the height direction between the fastening tools on the other side. A fastening structure for a fire-resistant covering material in an exterior wall panel.

2. The fastening structure for a fire-resistant covering material in an exterior wall panel according to claim 1, The back surface of the concrete panel is covered with one or more pieces of the fire-resistant covering material cut to the full width of the concrete panel. A fastening structure for a fire-resistant covering material in an exterior wall panel.

3. The fastening structure for a fire-resistant covering material in an exterior wall panel according to claim 1 or 2, Where two concrete panels are adjacent across a joint, a fire-resistant coating material is laid between the stiffeners of the adjacent concrete panels. A fastening structure for a fire-resistant covering material in an exterior wall panel.

4. The fastening structure for a fire-resistant covering material in an exterior wall panel according to claim 3, The fire-resistant covering material for the back of the joint and the fire-resistant covering material covering substantially the entire surface of the concrete panel are overlapped so that their joint positions do not match each other. A fastening structure for a fire-resistant covering material in an exterior wall panel.

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