Fire-resistant structure of the joints of exterior wall panels

Abstract

To provide a fire-resistant joint structure that can improve the fire resistance of joints between exterior wall panels, such as sandwich panels, with a simple configuration. [Solution] The fire-resistant structure for the joints of exterior wall panels is a fire-resistant structure for the joints (21) of an exterior wall panel (1) in which a core material is covered with an outdoor steel plate and an indoor steel plate, and comprises a joint member (4, 5) including a first covering portion (42) that closes the outdoor end of the joint and a second covering portion (52) located on the indoor side of the first covering portion, a first thermal expansion fire-resistant material (71) attached to the back surface of the first covering portion as viewed from the outdoor side, and a second thermal expansion fire-resistant material (72) attached to the surface of the second covering portion as viewed from the outdoor side.

Description

Technical Field

[0001] The present invention relates to a joint fireproof structure of an outer wall panel, and particularly to a fireproof structure at a joint between outer wall panels (so-called sandwich panels) whose both sides of the outdoor side and the indoor side are covered with steel plates.

Background Art

[0002] In a steel-frame building such as a logistics facility, an outer wall panel having a metal sandwich structure may be used. This outer wall panel is covered on both sides by an outdoor steel plate and an indoor steel plate. A joint fireproof structure of this type of outer wall panel (hereinafter referred to as a "sandwich panel") is proposed in Japanese Patent Laid-Open No. 7-252928 (Patent Document 1).

[0003] The fireproof structure of Patent Document 1 is to couple an inverted hat-shaped metal decorative cover and a hat-shaped metal joiner at a joint portion, and insert a fireproof heat insulating material between them.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Generally, the exterior and interior steel plates of a sandwich panel are not connected to each other, and each is independently bonded to the core material. Furthermore, the sandwich panel is fixed to the furring strips only at the top end, and multiple sandwich panels are installed by fitting them together vertically. As a result, when heated from the outside, the exterior steel plate deforms due to heat, causing the side and bottom edges of the exterior steel plate to lift away from the core material. When the vertical and horizontal joints expand due to the lifting (opening) of the exterior steel plate, the combustion of the core material tends to be accelerated, making it difficult to obtain sufficient fire resistance even if a fire-resistant structure like that in Patent Document 1 is adopted.

[0006] The present invention was made to solve the above-mentioned problems, and its objective is to provide a joint fire-resistant structure that can improve the fire resistance of joints between exterior wall panels such as sandwich panels with a simple configuration. [Means for solving the problem]

[0007] A fire-resistant joint structure for an exterior wall panel according to a certain aspect of this invention is a fire-resistant structure for a joint in an exterior wall panel in which a core material is covered with an exterior steel plate and an interior steel plate, and comprises a joint member including a first covering portion that closes the exterior end of the joint and a second covering portion located more interior than the first covering portion, a first thermal expansion fire-resistant material attached to the back surface of the first covering portion as viewed from the exterior, and a second thermal expansion fire-resistant material attached to the surface of the second covering portion as viewed from the exterior.

[0008] In cases where the joint is a vertical joint, it is desirable that the first covering portion is composed of a hat-shaped protrusion of a first vertical joint member that covers the vertical joint, and the second covering portion is composed of a hat-shaped protrusion of a second vertical joint member that is fixed to the furring strip.

[0009] Preferably, the fire-resistant structure of the joints of the exterior wall panels further comprises a third thermally expanding fire-resistant material attached to the side end surface of the core material. In this case, the outdoor end of the third thermally expanding fire-resistant material is inserted into the gap between the bent piece of the outdoor steel plate and the side end surface of the core material.

[0010] In cases where the joint is a horizontal joint, it is desirable that the first covering portion is composed of the lower flange of the horizontal joint member positioned in a recess formed on the outdoor surface of the upper end of the exterior wall panel, and the second covering portion is composed of the upper flange of the horizontal joint member.

[0011] Preferably, the horizontal joint member includes a first horizontal joint member fixed to the recess and a second horizontal joint member fixed to the back surface of a downward projection formed at the lower end of the exterior wall panel, the second horizontal joint member having a hooking portion that hooks onto an upper protrusion of the recess or the first horizontal joint member. [Effects of the Invention]

[0012] According to the present invention, the fire resistance of the joints between exterior wall panels, such as sandwich panels, can be improved with a simple configuration. [Brief explanation of the drawing]

[0013] [Figure 1] This is a schematic front view showing the exterior wall of a building in an embodiment of the present invention. [Figure 2] This is a schematic cross-sectional view showing a fire-resistant structure for vertical joints in an embodiment of the present invention. [Figure 3] This is a cross-sectional view showing a disassembled fire-resistant reinforcement device for vertical joints in an embodiment of the present invention. [Figure 4] This is a schematic diagram illustrating the fire resistance performance of the vertical joint in an embodiment of the present invention. [Figure 5] This is a schematic cross-sectional view showing a fire-resistant structure for a horizontal joint in an embodiment of the present invention. [Figure 6] This is a disassembled cross-sectional view showing a fire-resistant reinforcing device for a horizontal joint attached to the lower end of an exterior wall panel in an embodiment of the present invention. [Figure 7] This is a cross-sectional view showing a disassembled fire-resistant reinforcing device for a horizontal joint attached to the upper end of an exterior wall panel in an embodiment of the present invention. [Figure 8] This is a perspective view showing the first horizontal joint member in an embodiment of the present invention. [Figure 9] It is a schematic diagram for explaining the fire resistance performance of the horizontal joint in the embodiment of the present invention. [Figure 10] It is a schematic front view of a known building exterior wall. [Figure 11] It is a diagram schematically showing the basic structure of the vertical joint of the building exterior wall. [Figure 12] It is a diagram schematically showing the basic structure of the horizontal joint of the building exterior wall. [Figure 13] It is a schematic diagram for explaining the fire resistance performance of a known joint structure (vertical joint). [Figure 14] It is a schematic diagram for explaining the fire resistance performance of a known joint structure (horizontal joint).

Embodiments for Carrying Out the Invention

[0014] Embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and their descriptions will not be repeated.

[0015] <Regarding the Basic Configuration of the Sandwich Panel> First, referring to FIGS. 10 to 12, the basic configuration of the sandwich panel 1 will be briefly described. FIG. 10 is a schematic front view of the configuration of the building exterior wall. FIG. 11 is a diagram schematically showing the basic structure of the vertical joint 21 of the building exterior wall, and is an enlarged cross-sectional view of the portion XI enclosed by the broken line in FIG. 10. FIG. 12 is a diagram schematically showing the basic structure of the horizontal joint 22 of the building exterior wall, and is an enlarged longitudinal sectional view of the portion XII enclosed by the broken line in FIG. 10. In these figures, the vertical direction of the sandwich panel 1 is indicated by an arrow A1, and the lateral width direction (left-right direction) of the sandwich panel 1 is indicated by an arrow A2. Also, the arrow A3 in FIG. 11 indicates the indoor side. The same applies to other figures.

[0016] As shown in FIG. 10, a plurality of sandwich panels 1 are arranged in alignment in the vertical direction (vertical direction) and the horizontal direction (horizontal direction) to form the building exterior wall. A vertical joint 21 is formed between the left and right sandwich panels 1, and a horizontal joint 22 is formed between the upper and lower sandwich panels 1.

[0017] As shown in Figure 11, the sandwich panel 1 is an exterior wall panel in which both the outdoor and indoor sides are covered with steel plates 11 and 12 (shown by thick lines in the drawing). The core material 13 of the sandwich panel 1 is made of an organic insulation material such as polyisocyanurate foam and is integrated with the outdoor steel plate 11 and the indoor steel plate 12. The outdoor steel plate 11 and the indoor steel plate 12 are bonded to the core material 13. The thickness of the sandwich panel 1 is relatively large, for example, about 100 mm.

[0018] The side end 11a of the outdoor steel plate 11 adjacent to the vertical joint 21 is bent into an L-shape, and the bent piece 11b is in contact with or close to a portion of the side end surface 13a of the core material 13 (in some cases, it is glued). On the other hand, the side end of the indoor steel plate 12 is not bent, and the remaining portion of the side end surface 13a of the core material 13 is exposed.

[0019] As shown in Figure 12, the sandwich panels 1, which are continuous in the vertical direction, are assembled by fitting the upper end 10a and the lower end 10b together. Generally, the upper end 10a of the sandwich panel 1 has a projection 15a that protrudes upward, and the lower end 10b has a groove 15b that receives the projection 15a. Two projections 15a and two grooves 15b are provided.

[0020] The folded portion 11d of the upper end 11c of the outdoor steel plate 11 forms the convex shape of the outdoor protruding portion 15a, and the folded portion 12b of the upper end 12a of the indoor steel plate 12 forms the convex shape of the indoor protruding portion 15a. The upper end surface 13c of the core material 13 (or the waterproof film attached to the upper end surface 13c of the core material 13) is exposed between the two protruding portions 15a. The folded portion 11f of the lower end 11e of the outdoor steel plate 11 forms the concave shape of the outdoor groove portion 15b, and the folded portion 12d of the lower end 12c of the indoor steel plate 12 forms the concave shape of the indoor groove portion 15b. The lower end surface 13b of the core material 13 (or the waterproof film attached to the lower end surface 13b of the core material 13) is exposed between the two groove portions 15b.

[0021] In the installed state, the upper end portion 10a of the sandwich panel 1 is fixed to the furring strip 14 with fastening members 16 such as screws. The furring strip 14 is typically made of square steel, with the outdoor side forming the mounting surface. In the installed state of the sandwich panel 1, the heads 16h of the fastening members 16 (hereinafter referred to as "screw heads") are housed in the horizontal joint space S2 and are concealed by the downward projection 1b formed on the lower end portion 10b of the upper sandwich panel 1. The downward projection 1b overlaps in the inward and outward directions with the recess 1a formed on the upper end portion 10a of the sandwich panel 1, and in this embodiment, the horizontal joint space S2 is the space (gap) between the downward projection 1b and the recess 1a.

[0022] As shown in Figure 11, the sandwich panels 1, which are continuous in the left-right direction, do not overlap, and the gaps between two adjacent sandwich panels 1 in the left-right direction form vertical joints 21. The furring strips 14 are positioned at locations corresponding to the vertical joints 21 (joint centers). In known fire-resistant joint structures, a sealing member 131 (including, for example, an insulating material similar to the core material 13, or a wet or dry sealing material) is filled to fill the vertical joints 21 between the sandwich panels 1. Also, as shown in Figure 11, a sheet-like or thin plate-like waterproofing material 132 may be provided on the back side (indoor side) of the sandwich panel 1. The waterproofing material 132 is attached to the entire mounting surface of the furring strips 14. Note that in Figure 11, a gap is provided between the sealing member 131 and the side end surface 13a of the core material 13 for ease of understanding.

[0023] As shown in Figure 13(A), when the exterior wall of a building is heated from the outside, the exterior steel plate 11 warps over time due to thermal deformation, and as shown in Figure 13(B), the side edge 11a of the exterior steel plate 11 lifts up away from the core material 13. In this case, the gap between the lifted side edge 11a of the exterior steel plate 11 and the core material 13 becomes a passage for heat, promoting the combustion of the core material 13. Therefore, even if the vertical joint 21 is filled with a sealing member 131, the heat from the combustion of the core material 13 can reach the back side of the sandwich panel 1 and potentially cause flames to erupt on the indoor side. Specifically, flames may erupt from the tiny gap between the indoor steel plate 12 and the furring strip 14 of the sandwich panel 1.

[0024] Furthermore, as shown in Figure 14, at the lower end 10b of the sandwich panel 1, the lower end 11e of the outdoor steel plate 11 lifts away from the core material 13, and the horizontal joint space S2 expands. Also, at the upper end 10a of the sandwich panel 1, the upper end 11c of the outdoor steel plate 11 lifts away from the core material 13 in areas other than those fixed by the fastening member 16. As a result, heat penetrates from the horizontal joint space S2, accelerating the combustion of the core material 13 (indicated by the dashed arrow).

[0025] In contrast, the fire-resistant structure of the building's exterior wall in this embodiment includes a "fire-resistant reinforcement" that prevents heat transfer from the metal exterior steel plate 11 to the interior steel plate 12 while improving the fire resistance performance at the joints (vertical joints 21 and horizontal joints 22). The fire-resistant reinforcement will be described in detail below.

[0026] <Fire-resistant structure with vertical joints> Referring to Figures 1 to 3, the fire-resistant structure of the vertical joint 21 according to this embodiment will be described. Figure 1 is a front view (viewed from the outside) showing the vertical joint 21 with the fire-resistant reinforcement 3 installed. Figure 2 is a schematic cross-sectional view showing the fire-resistant structure of the vertical joint, and shows an enlarged view of the cross section II enclosed by the dashed line in Figure 1. Figure 3 is an exploded view of the fire-resistant reinforcement 3.

[0027] As shown in Figure 2, the fire-resistant reinforcement 3 comprises a first vertical joint member 4 and a second vertical joint member 5 arranged facing each other in the depth direction with the vertical joint 21 in between, and a fastener 61 that connects (fastens) the first vertical joint member 4 and the second vertical joint member 5. It also comprises heat-expandable fire-resistant materials 71 and 72 that are attached to the back surface of the first vertical joint member 4 and the front surface of the second vertical joint member 5, respectively, and a heat-expandable fire-resistant material 73 that is attached to the side end surface 13a of the core material 13. The heat-expandable fire-resistant materials 71, 72, and 73 are made of, for example, heat-expandable tape with adhesive tape applied to the back surface of a sheet-like heat-expandable fire-resistant material. In each figure, the heat-expandable fire-resistant material is shown in gray.

[0028] The first and second vertical joint members 4 and 5 are both made of long, vertically elongated (non-combustible) metal plate-like members (see Figure 1), and their thickness is, for example, greater than or equal to the thickness of the steel plates 11 and 12 of the sandwich panel 1. The width of the first and second vertical joint members 4 and 5 is typically approximately the same as the width of the furring strips 14. The material of the first and second vertical joint members 4 and 5 is not limited to metal, as long as it is a hard, fire-resistant material. Also, the first and second vertical joint members 4 and 5 do not have to be plate-like.

[0029] The first vertical joint member 4 is positioned on the outdoor side of the vertical joint 21 and functions as a vertical joint cover. The first vertical joint member 4 integrally includes a covering portion (outdoor covering portion) 42 that covers the vertical joint 21 and a contact portion (outdoor contact portion) 41 that is applied to the surface of the end portion 11a of the outdoor steel plate 11. As shown in Figures 2 and 3, the first vertical joint member 4 in this embodiment has a hat-shaped cross-section. Therefore, the first vertical joint member 4 is composed of a pair of contact portions 41 and a covering portion 42 that is connected to the widthwise inner ends (ends on the vertical joint 21 side) of the pair of contact portions 41 and is formed in a U-shape. A folded portion 41a that is folded inward is provided at the outer end of the contact portion 41.

[0030] In the installed state, the covering portion 42 is composed of a protrusion that extends inward from the pair of contact portions 41 and is housed within the vertical joint 21. Therefore, when the first vertical joint member 4 is viewed from the outside, a recess is formed by the covering portion 42. The covering portion 42 is composed of a pair of side portions that follow the end face of the sandwich panel 1 (typically the bent piece 11b of the outdoor steel plate 11) and a tip portion that is perpendicular (intersects) to the said end face.

[0031] It is desirable that the covering portion 42 be positioned within the range of the bent portion 11b of the outdoor steel plate 11. It is also desirable that the protruding length (height of the protrusion) of the covering portion 42 be greater than or equal to the depth of the horizontal joint 22 (depth of the recess 1a) of the sandwich panel 1. This prevents rainwater and heat from entering the insulated space S1 located on the indoor side of the covering portion 42, which will be described later, through the horizontal joint 22.

[0032] The second vertical joint member 5 is positioned on the indoor side of the vertical joint 21 and functions as a drip edge. It also functions as a fixing bracket for the first vertical joint member 4. The second vertical joint member 5 integrally has a covering portion (indoor covering portion) 52 that covers the vertical joint 21 and a contact portion (indoor contact portion) 51 that is applied to the surface of the end portion 12a of the indoor steel plate 12. As shown in Figures 2 and 3, the second vertical joint member 5 in this embodiment also has a hat-shaped cross-section. Therefore, the second vertical joint member 5 is composed of a pair of contact portions 51 and a covering portion 52 that is connected to the widthwise inner ends (ends on the vertical joint 21 side) of the pair of contact portions 51 and is formed in a U-shape.

[0033] In the installed state, the covering portion 52 is composed of protrusions that extend outward from the pair of contact portions 51 and is housed within the vertical joint 21. Therefore, when the second vertical joint member 5 is viewed from the indoor side, a recess is formed by the covering portion 52. The covering portion 52 is composed of a pair of side portions that follow the end face of the sandwich panel 1 (the side end face 13a of the core material 13) and a tip portion that is perpendicular (intersects) to the said end face. From the viewpoint of preventing thermal bridging, it is desirable that the covering portion 52 be located outside the range of the bent piece 11b of the outdoor steel plate 11.

[0034] The covering portion 52 (tip) of the second vertical joint member 5 and the covering portion 42 (tip) of the first vertical joint member 4 are separated in the depth direction, and the space between the two covering portions 42 and 52 is hereinafter referred to as the thermal insulation space S1. The thermal insulation space S1 is formed in a position that spans both the folded piece 11b and the exposed side end surface 13a of the core material 13. In this embodiment, as shown in Figure 2, the thermal insulation space S1 is provided in the center of the sandwich panel 1 in the thickness direction.

[0035] The thermal expansion fire-resistant material 71 is attached to almost the entire back surface (concave side) of the first vertical joint member 4 (excluding the folded portion 41a) when viewed from the outside. The thermal expansion fire-resistant material 72 is attached to almost the entire surface (convex side) of the second vertical joint member 5 when viewed from the outside. The outdoor end of the thermal expansion fire-resistant material 73 is inserted into the gap between the folded piece 11b of the outdoor steel plate 11 and the side end surface 13a of the core material 13. The thermal expansion fire-resistant material 73 is applied in an L-shape, and the indoor end of the thermal expansion fire-resistant material 73 overlaps (is attached to) the indoor steel plate 12.

[0036] The installation method for the fire-resistant reinforcement device 3 is as follows: First, heat-expandable fire-resistant material 73 is pre-attached to cover the side end surface 13a (exposed portion) of the core material 13 of the sandwich panel 1. Also, heat-expandable fire-resistant material 71 is attached to the back surfaces of the pair of contact portions 41 and covering portions 42 of the first vertical joint member 4 so as to conform to the shape of the first vertical joint member 4. Furthermore, heat-expandable fire-resistant material 72 is attached to the back surfaces of the pair of contact portions 51 and covering portions 52 of the second vertical joint member 5 so as to conform to the shape of the second vertical joint member 5, and fire-resistant material 94 is pre-filled inside the covering portion 52 of the second vertical joint member 5. As the fire-resistant material 94, for example, fibrous material such as AES (alkali earth silicate) wool can be used.

[0037] First, the second vertical joint member 5 is fixed to the furring strip 14 with fasteners 62 such as screws. Next, a wet or dry fire-resistant sealant 93 is applied to or attached to the outer end of the contact portion 51 of the second vertical joint member 5. The heat-expanding fire-resistant material 72 is attached with an excess at the outer end of the contact portion 51, and the outer space of the heat-expanding fire-resistant material 72 is sealed by the fire-resistant sealant 93. In this state, the sandwich panel 1 is assembled and fixed to the furring strip 14.

[0038] Next, the interior of the vertical joint 21 (insulation space S1) is filled with fire-resistant material 91, and then the first vertical joint member 4 is fixed in place. The first vertical joint member 4 is connected and fixed to the second vertical joint member 5 by fasteners 61 that penetrate the covering portion 42 and the covering portion 52. The fasteners 61 are made of, for example, tapping screws. The fasteners 61 fasten both ends of the first vertical joint member 4 and the second vertical joint member 5, with the contact portion 41 of the first vertical joint member 4 and the contact portion 51 of the second vertical joint member 5 clamping the end of the sandwich panel 1 in the thickness direction. It is desirable that the fasteners 61 be installed only at the upper and lower ends of the sandwich panel 1.

[0039] Finally, a wet or dry fire-resistant sealant 95 is filled into the recess of the first vertical joint member 4.

[0040] <Effects and Effects> The fire resistance performance of the building's exterior wall (sandwich panel 1) with the fire-resistant reinforcement device 3 described above applied to the vertical joints 21 will be explained.

[0041] As shown in Figure 2, a pair of contact portions 41 of the first vertical joint member 4 are in surface contact with the ends 11a of the outdoor steel plates 11 located on both sides of the vertical joint 21 via the heat-expanding fire-resistant material 71. In addition, the fasteners 61 maintain a constant distance between the first vertical joint member 4 and the second vertical joint member 5 (preventing them from separating). Therefore, even when heated from the outside, the lifting of the ends 11a due to thermal deformation of the outdoor steel plates 11 can be suppressed. Furthermore, since the heat-expanding fire-resistant material 71 is provided on the back surface of the covering portion 42 of the first vertical joint member 4, even if heat penetrates from the outer end of the contact portion 41, the heat-expanding fire-resistant material 71 expands, effectively suppressing heat input at the entrance to the insulated space S1.

[0042] Furthermore, even if heat were to penetrate the insulated space S1, the heat-expanding fire-resistant material 72 is also provided on the surface of the covering portion 52 of the second vertical joint member 5, which can delay heat transfer from the insulated space S1 to the back side. In this way, the penetration of heat through the insulated space S1 can be suppressed in stages (at the inlet and outlet).

[0043] Furthermore, since the second vertical joint member 5 is separated from both the first vertical joint member 4 and the bent piece 11b of the outdoor steel plate 11, heat transfer from the first vertical joint member 4 and the bent piece 11b to the second vertical joint member 5 can be suppressed. In other words, the first vertical joint member 4 and the second vertical joint member 5 do not form a thermal bridge.

[0044] Furthermore, as shown in Figure 4, while the outdoor steel plate 11 expands outward due to thermal expansion when heated, the core material 13 inside the outdoor steel plate 11 contracts due to combustion, and the gap in the vertical joint 21 (insulation space S1) expands. However, the heat-expanding fire-resistant material 73 attached to both sides of the insulation space S1 (side end faces 13a of the core material 13) expands and fills the gap. This slows down the decrease in insulation performance in the insulation space S1. As a result, heat transfer to the back side is delayed, and fire resistance is improved. In other words, it is possible to prevent flames from igniting on the back side (indoor side) of the sandwich panel 1, as shown in Figure 13(B).

[0045] Furthermore, the fixing position of the fastener 61 of the first vertical joint member 4 is approximately the same as the fixing position of the fastener 16 for fixing the sandwich panel 1 (no fastener 61 is installed in the vertical center of the sandwich panel 1). As a result, the deflection of the first vertical joint member 4 between the upper and lower fasteners 16 and the out-of-plane deflection of the first vertical joint member 4 are approximately the same. Therefore, even when the outdoor steel plate 11 undergoes thermal expansion, the outdoor steel plate 11 and the first vertical joint member 4 remain in close contact, making it difficult for large gaps to form and preventing a decrease in fire resistance.

[0046] <Fire-resistant structure with horizontal joints> Referring to Figures 5 to 7, the fire-resistant structure of the horizontal joint 22 in this embodiment will be described. Figure 5 is a schematic cross-sectional view showing the fire-resistant structure of the horizontal joint 22. Figures 6 and 7 are disassembled cross-sectional views showing the fire-resistant reinforcement 8 of the horizontal joint 22.

[0047] As shown in Figure 5, a fire-resistant reinforcement 8 is placed in the horizontal joint space S2 formed by the overlapping portion of the upper sandwich panel 1 and the lower sandwich panel 1. The fire-resistant reinforcement 8 includes first and second joint members 81 and 82 placed in the horizontal joint space S2. It also includes thermally expanding fire-resistant materials 74 and 75 that cover the lower end surface 13b and upper end surface 13c of the core material 13.

[0048] The first horizontal joint member 81 is typically composed of a metal plate-like member having a substantially U-shaped (U-shaped) cross-section and is fixed to the outdoor surface of the upper end 10a of the sandwich panel 1. As shown in Figure 8, it is desirable that the first horizontal joint member 81 is a long member that extends along the width direction (horizontal direction) of the sandwich panel 1. The thickness of the first horizontal joint member 81 is, for example, about 0.5 to 1.6 mm.

[0049] The first horizontal joint member 81 is sized to fit within the horizontal joint space S2 and is fixed to the recess 1a. The first horizontal joint member 81 includes a vertical portion 811 extending in the vertical direction and flanges 812 and 813 protruding to the outside from the upper and lower edges of the vertical portion 811. The first horizontal joint member 81 is fastened to the upper end portion 11c of the outdoor steel plate 11 by screws that pass through the vertical portion 811. As shown in Figure 8, the first horizontal joint member 81 may have pre-drilled holes 810 for inserting screws. The fixing pitch (screw arrangement pitch) of the first horizontal joint member 81 is shorter than the left-right arrangement pitch of the fasteners 61 (arrangement pitch of the furring strips 14). As shown in Figure 7, in this embodiment, the protruding dimension of the upper flange 812 is shorter than the protruding dimension of the lower flange 813.

[0050] The second horizontal joint member 82 is also sized to fit within the horizontal joint space S2 and is composed of a metal plate-like member extending horizontally. The second horizontal joint member 82 is fixed to the back surface of the lower end portion 10b (downward projection 1b) of the sandwich panel 1. The second horizontal joint member 82 includes a vertical portion 821 extending in the vertical direction and flanges 822 and 823 protruding to the outside from the upper and lower edges of the vertical portion 821. The second horizontal joint member 82 is fastened to the lower end portion 11e of the outdoor steel plate 11 by screws that pass through the vertical portion 821. The upper flange 822 is oriented diagonally upward so as to conform to the shape of the back surface of the downward projection 1b.

[0051] With the first and second horizontal joint members 81 and 82 fixed in place, the upper and lower sandwich panels 1 are assembled. The fastening member 16 for fixing the upper end 10a of the sandwich panel 1 to the furring strip 14 passes through the first horizontal joint member 81. As a result, the first horizontal joint member 81 is firmly fastened to the furring strip 14 and also functions as a pressing member that presses down on the upper end 11c of the outdoor steel plate 11 from the outside.

[0052] As shown in Figure 1, when the upper and lower sandwich panels 1 are fitted together, the first and second horizontal joint members 81 and 82 are housed in the horizontal joint space S, facing each other. The horizontal joint space S2 is surrounded (without any intentional gaps) by the first and second horizontal joint members 81 and 82. The upper flange 822 of the second horizontal joint member 82 is provided with a hooking portion 824 at its tip so as to catch on a protrusion 11g formed above the recess 1a of the sandwich panel 1.

[0053] As shown in the figure, the thermal expansion fire-resistant material 76 is attached to the entire inner surface of the first horizontal joint member 81. Similarly, the thermal expansion fire-resistant material 77 is attached to the entire inner surface of the second horizontal joint member 82.

[0054] In the installed state, the lower flange 813 of the first horizontal joint member 81 extends to the vicinity of the back surface of the downward projection 1b, and the lower flange 823 of the second horizontal joint member 82 overlaps with the tip of the lower flange 813 (thermal expansion fire-resistant material 76) of the first horizontal joint member 81. As a result, the lower end (outdoor side end) of the horizontal joint space S2 is closed by the lower flange 813 of the first horizontal joint member 81 alone, or in combination with the lower flange 823 of the second horizontal joint member 82. In this embodiment, the lower flange 813 functions as a first covering portion that closes the lower end of the horizontal joint space S2.

[0055] The tip of the upper flange 812 of the first horizontal joint member 81 contacts or is close to the locking portion 824 of the upper flange 822 of the second horizontal joint member 82. As a result, the upper end of the horizontal joint space S2 is closed by the combination of the upper flange 812 of the first horizontal joint member 81 and the upper flange 822 of the second horizontal joint member 82. In this embodiment, the two upper flanges 812 and 822, which are located further back (indoor side) than the lower flange 813 (first covering portion) when viewed from the outdoor side, function as a second covering portion that closes the upper end (indoor side end) of the horizontal joint space S2.

[0056] Since the first horizontal joint member 81 has a heat-expanding fire-resistant material 76 attached to it, and the second horizontal joint member 82 also has a heat-expanding fire-resistant material 77 attached to it, the horizontal joint space S is almost completely enclosed by the heat-expanding fire-resistant materials 76 and 77.

[0057] It is desirable that the heat-expanding fire-resistant material 74 provided on the lower end surface of the sandwich panel 1 be positioned so that both ends overlap the folded portion 11f of the lower end 11e of the outdoor steel plate 11 and the folded portion 12d of the lower end 12c of the indoor steel plate 12. It is also desirable that the heat-expanding fire-resistant material 75 provided on the upper end surface of the sandwich panel 1 be positioned so that both ends overlap the folded portion 11d of the upper end 11c of the outdoor steel plate 11 and the folded portion 12b of the upper end 12a of the indoor steel plate 12. In the installed state, the upper and lower heat-expanding fire-resistant materials 74 and 75 overlap in close contact at least a portion (the central part). It is also desirable that the groove 15b formed in the lower end 10b of the sandwich panel 1 be pre-filled with fire-resistant sealing material 96.

[0058] <Effects and Effects> The fire resistance performance of the building's exterior wall (sandwich panel 1) with the above-described fire-resistant reinforcement device 8 applied to the horizontal joint 22 will be explained.

[0059] As shown in Figure 9, when heated from the outside, the outdoor steel plate 11 of the sandwich panel 1 bulges outward due to the heating, causing the horizontal joint space S2 to open. However, the latching portion 824 of the second horizontal joint member 82 catches on the protrusion 11g of the sandwich panel 1, thus suppressing the opening of the horizontal joint space S2. In other words, the separation of the first horizontal joint member 81 and the second horizontal joint member 82 can be suppressed. This delays the intrusion of heat into the interior of the horizontal joint space S2.

[0060] Furthermore, since the heat-expanding fire-resistant material 76 is provided up to the tip of the lower flange 823 of the first horizontal joint member 81, even if heat enters from the tip side of the lower flange 823, the heat-expanding fire-resistant material 76 will expand, effectively suppressing heat input at the entrance of the horizontal joint space S2.

[0061] Furthermore, even if heat were to penetrate the horizontal joint space S2, the heat-expanding fire-resistant materials 76 and 77 are also provided on the surfaces of the upper flange 812 of the first horizontal joint member 81 and the upper flange 822 of the second horizontal joint member 82, which are located above the horizontal joint space S2. This delays the transfer of heat from the horizontal joint space S2 to the upper and lower fitting gaps of the sandwich panel 1 (the fitting locations of the protruding portion 15a and the groove portion 15b). In this way, the penetration of heat through the insulating space S1 can be suppressed in stages (at the inlet and outlet).

[0062] Furthermore, even if the first horizontal joint member 81 and the second horizontal joint member 82 separate, the periphery of the horizontal joint space S2 is surrounded by the thermally expanding fire-resistant materials 76 and 77. Therefore, the expansion of the thermally expanding fire-resistant materials 76 and 77 fills the gap in the horizontal joint space S2, slowing down combustion inside.

[0063] Furthermore, even if the core material 13 burns due to heating and shrinks, the thermally expanding fire-resistant material 74 on the lower end surface 13b and the thermally expanding fire-resistant material 75 on the upper end surface 13c of the core material 13 expand, filling the gaps between the core materials 13. This delays heat transfer to the back side, thereby improving fire resistance.

[0064] In this configuration, the latching portion 824 of the second horizontal joint member 82 latches onto the protrusion 11g above the recess 1a, but it may also latch onto the tip of the upper flange 812 of the first horizontal joint member 81.

[0065] Furthermore, in this embodiment, an example is shown in which the first horizontal joint member 81 and the second horizontal joint member 82 are arranged facing each other in the horizontal joint space S2. However, the horizontal joint member arranged in the horizontal joint space S2 may consist only of the first horizontal joint member 81, and the upper flange 812 may be made longer.

[0066] As explained above, since the building exterior wall according to this embodiment is provided with the aforementioned fire-resistant reinforcement in the joints, it is possible to achieve (or approach) the desired fire resistance performance even when the thermal insulation performance of the core material 13 of the existing sandwich panel 1 is relatively low.

[0067] Furthermore, since the fire-resistant reinforcement does not have metal fittings that form a thermal bridge between the outdoor steel plate 11 and the indoor steel plate 12, it is possible to improve heat resistance performance inexpensively and easily.

[0068] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of Symbols]

[0069] 1: Sandwich panel, 1a: Recessed section, 1b: Downward protrusion, 3: Fire-resistant reinforcement, 4: First vertical joint member, 5: Second vertical joint member, 8: Fire-resistant reinforcement, 11: Outdoor steel plate, 12: Indoor steel plate, 13: Core material, 14: Furring strip, 16: Fastening member, 21: Vertical joint, 22: Horizontal joint, 42: Covering section, 52: Covering section, 71-77: Thermal expansion fire-resistant material, 81: First horizontal joint member, 82: Second horizontal joint member, S1: Insulation space, S2: Horizontal joint space.

Claims

1. A fire-resistant structure for the joints of exterior wall panels in which a core material is covered with an exterior steel plate and an interior steel plate, A joint member comprising a first covering portion that closes the outdoor end of the joint and a second covering portion located on the indoor side of the first covering portion, A first heat-expandable fire-resistant material is attached to the back surface of the first covering portion as viewed from the outside, A fire-resistant joint structure for an exterior wall panel, comprising a second heat-expandable fire-resistant material attached to the surface of the second covering portion as viewed from the outside.

2. The aforementioned joint is a vertical joint, The first covering portion is composed of a hat-shaped protrusion of the first vertical joint member that covers the vertical joint, The fire-resistant joint structure for an exterior wall panel according to claim 1, wherein the second covering portion is composed of a hat-shaped second vertical joint member fixed to the furring strip.

3. The core material further comprises a third heat-expandable fire-resistant material attached to its side end surface, The fire-resistant joint structure for an exterior wall panel according to claim 2, wherein the outdoor end of the third heat-expandable fire-resistant material is inserted into the gap between the bent piece of the outdoor steel plate and the side end face of the core material.

4. The aforementioned joint is a horizontal joint, The first covering portion is composed of the lower flange of a horizontal joint member that is positioned in a recess formed on the outdoor surface of the upper end of the exterior wall panel. The fire-resistant joint structure for an exterior wall panel according to claim 1, wherein the second covering portion is formed by the upper flange of the horizontal joint member.

5. The horizontal joint member includes a first horizontal joint member fixed to the recessed portion and a second horizontal joint member fixed to the back surface of the downward projection formed at the lower end of the exterior wall panel. The fire-resistant joint structure for an exterior wall panel according to claim 4, wherein the second horizontal joint member has a protrusion above the recess or a hooking portion that hooks onto the first horizontal joint member.

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