Fire-resistant cladding structure for steel beams

Abstract

This invention provides a fire-resistant covering structure for steel beams that offers high airtightness against gases and other gases, making it difficult for gases to leak into adjacent rooms. [Solution] The present invention relates to a fire-resistant covering structure for a steel beam 1 installed so as to penetrate a wall 20, comprising a steel beam 1, a fire-resistant covering material 2, and a sealing material 3, wherein the steel beam 1 has a long web portion 1a and a pair of flange portions 1b formed at both ends of the web portion 1b, the sealing material 3 is provided on the web portion 1a and is positioned to connect with the wall 20, the fire-resistant covering material 2 is bonded to the side end surface and bottom surface of the sealing material 3 so as to cover the sides and bottom of the steel beam 1, and a sealing layer 30 is interposed between the fire-resistant covering material 2 and the sealing material 3.

Description

Technical Field

[0001] The present invention relates to a fireproof coating structure for a steel beam.

Background Art

[0002] In buildings where the installation of gas fire extinguishing equipment is mandatory under the Fire Service Act, airtightness with respect to gas is required so that the extinguishing gas generated when the gas fire extinguishing equipment operates due to a fire or the like does not leak into adjacent rooms.

[0003] Generally, in a building, walls such as walls (partition walls) and partition walls for forming a fire compartment (hereinafter simply referred to as walls) are installed to prevent the spread of fire in the building, and a steel beam is provided so as to penetrate the wall. A method of coating the steel beam with a refractory material to impart fire resistance and ensure airtightness is known, and by this method, it is possible to suppress the leakage of extinguishing gas or the like generated when the gas fire extinguishing equipment operates into adjacent rooms. As a specific method, a method of coating the steel beam with a fibrous refractory material such as rock wool is known.

[0004] Further, Patent Document 1 discloses a fireproof structure having a coating material formed by attaching and integrating an airtight sheet having airtightness on at least one surface of a refractory material, and it is considered that an airtight fireproof coating structure having sufficient fire resistance and airtightness can be obtained by such a fireproof structure.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] To ensure fire resistance, one possible method is to use foaming paint, which foams up during a fire (i.e., to form a carbonized layer). However, when using foaming paint, a gap (clearance) is required for the paint to foam, and the presence of this gap makes it prone to leakage of fire extinguishing gas.

[0007] For example, one method to improve airtightness is to cover the aforementioned steel frame with fibrous fire-resistant materials such as rock wool. However, because rock wool itself has relatively high gas permeability, there was a risk of fire extinguishing gases leaking out.

[0008] The present invention has been made in view of the above, and aims to provide a fire-resistant covering structure for steel beams that has high airtightness against gases and prevents gases from leaking into adjacent rooms. [Means for solving the problem]

[0009] As a result of diligent research to achieve the above objective, the inventors of the present invention have found that the above objective can be achieved by providing a fire-resistant coating material and a sealing material to a steel beam, and by interposing a sealing layer between the fire-resistant coating material and the sealing material, thereby completing the present invention.

[0010] In other words, the present invention encompasses, for example, the subject matter described in the following sections. Item 1 A fire-resistant covering structure for steel beams installed to penetrate a wall, It consists of steel beams, fire-resistant covering material, and sealing material. The steel beam has a long web portion and a pair of flange portions formed at both ends of the web portion. The aforementioned sealing material is provided in the web portion and is positioned at a location where it interacts with the wall. The fire-resistant covering material is attached to the side end surface and bottom surface of the sealing material and is provided to cover the sides and bottom of the steel beam. A fire-resistant covering structure for a steel beam, wherein a sealing layer is interposed between the fire-resistant covering material and the sealing material. Section 2 The fire-resistant covering structure for a steel beam according to item 1, wherein a clearance is formed between the fire-resistant covering material and the flange portion without contact. Section 3 The fire-resistant covering structure for a steel beam according to item 1 or 2, wherein the fire-resistant covering material and the side end face of the sealing material are connected by a fastener. Section 4 The fire-resistant covering material is a plate-shaped fire-resistant material formed in a long length, as described in any one of items 1 to 3, for the fire-resistant covering structure of a steel beam. Section 5 A fire-resistant covering structure for a steel beam according to any one of items 1 to 4, wherein the fire-resistant covering material is a calcium silicate board. Section 6 A fire-resistant covering structure for a steel beam according to any one of items 1 to 5, wherein the sealing material is a calcium silicate board. Section 7 A building having a fire-resistant covering structure for steel beams as described in any one of items 1 to 6. [Effects of the Invention]

[0011] The fire-resistant covering structure for steel beams of the present invention has high airtightness against gases, making it difficult for gases such as fire extinguishing gases to leak into adjacent rooms. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic diagram showing an example of an embodiment of the fire-resistant covering structure for steel beams of the present invention, where (a) is a cross-sectional view and (b) is a side view. [Figure 2] This is a schematic diagram showing an example of an embodiment of the fire-resistant covering structure for steel beams of the present invention, and is a part of a cross-sectional view when the web portion of the steel beam is cut vertically along a plane perpendicular to the height direction. [Figure 3] This is a cross-sectional view showing an example of an embodiment of the fire-resistant coating structure formed in Comparative Example 1 and Comparative Example 2. [Figure 4] This is a schematic diagram illustrating an evaluation device for conducting airtightness tests. [Modes for carrying out the invention]

[0013] Hereinafter, embodiments of the present invention will be described in detail. In this specification, the expressions "containing" and "including" include the concepts of "containing", "including", "substantially consisting of", and "consisting only of".

[0014] The present invention is a fireproof coating structure of a steel beam installed so as to penetrate a wall, and includes a steel beam, a fireproof coating material, and a plugging material. The steel beam has a long web portion and a pair of flange portions formed at both ends of the web portion, and the plugging material is provided on the web portion and is disposed at a position facing the wall.

[0015] The fireproof coating material is provided by being bonded to the side end surface and the lower surface of the plugging material so as to cover the side and the lower part of the steel beam, and a sealing layer is interposed between the fireproof coating material and the plugging material.

[0016] According to the fireproof coating structure of the steel beam of the present invention, the airtightness against gases and the like is high, and it is possible to prevent gases such as fire extinguishing gases from leaking into adjacent rooms and the like.

[0017] FIG. 1 is a schematic view showing an example of an embodiment of the fireproof coating structure of the steel beam of the present invention, where (a) is a cross-sectional view and (b) is a side view. Specifically, FIG. 1(a) is a cross-sectional view when the steel beam is cut along the height direction (the direction from one flange portion to the other flange portion) so as to pass through the plugging material 3 (that is, the cross-section cut along the B-B' line in FIG. 1(b)). FIG. 1(b) is a side view from the long side of the steel beam.

[0018] FIG. 2 is a schematic view showing an example of an embodiment of the fireproof coating structure of the steel beam of the present invention, and is a cross-sectional view when the web portion of the steel beam is cut along a plane perpendicular to the height direction (that is, cut along the A-A' line in FIG. 1(a)).

[0019] Hereinafter, the fireproof coating structure of the steel beam of the present invention will be described with reference to FIGS. 1 and 2.

[0020] The fire-resistant covering structure for a steel beam according to this embodiment (hereinafter referred to as "this embodiment" or "fire-resistant covering structure of this embodiment") comprises a steel beam 1, a fire-resistant covering material 2, and a sealing material 3, as shown in Figure 1(a).

[0021] The steel beam 1 is a so-called H-shaped steel member, and as shown in Figures 1(a) and (b), it is formed having a long web portion 1a and a pair of flange portions 1b formed at both ends (upper and lower ends) of the web portion 1a. The pair of flange portions 1b are flat plates and are formed along the entire length of the web portion 1a, and each flange portion 1b is formed at a right angle or approximately right angle to the web portion 1a, thereby forming an H-shaped cross-section.

[0022] One of the pair of flange portions 1b of the steel beam 1 (the flange portion 1b located above the building) is positioned, for example, facing the building's slab, particularly the floor slab 10.

[0023] In this specification, of the pair of flange portions 1b, the flange portion 1b located above the building (the flange portion 1b facing the floor slab 10) may be referred to as the upper flange portion 1b, and the flange portion 1b on the opposite side of the upper flange portion 1b may be referred to as the lower flange portion 1b.

[0024] In the fire-resistant covering structure of this embodiment, the steel beam 1 is installed with both ends penetrating the wall 20, as can be seen in Figures 1(b) and 2.

[0025] As long as the steel beam 1 has a web portion 1a and a flange portion 1b, its type is not particularly limited, and for example, known H-shaped steel used in steel beams can be widely used.

[0026] The sealing material 3 is, for example, a plate-shaped member, or a member formed by laminating an airtight film (for example, an aluminum film) onto a fibrous base material such as a blanket.

[0027] As can be seen in Figure 1(b), the sealing material 3 is provided in the web portion 1a and is positioned where it connects with the wall 20.

[0028] As shown in Figures 1(a) and 2, the sealing material 3 is positioned on both sides of the web portion 1a such that the sealing material 3 protrudes perpendicularly from the web portion 1a. The sealing material 3 is positioned in contact with the web portion 1a and the pair of flange portions 1b.

[0029] As can be seen from Figure 2, the position in which the sealing material 3 interacts with the wall 20 means that the sealing material 3 is positioned so that its side end face (the end face opposite the web portion) faces the wall 20. In the fire-resistant covering structure of this embodiment, a fire-resistant covering material, which will be described later, is interposed between the side end face of the sealing material 3 and the wall 20, so the sealing material 3 and the wall 20 do not come into direct contact. The wall 20 can be, for example, a wall that constitutes a fire compartment, a so-called compartment wall.

[0030] The sealing material 3 can be fixed to the web portion 1a and flange portion 1b by, for example, an adhesive material. The type of adhesive material is not particularly limited, and for example, a wide range of known sealing adhesives can be applied. Examples of sealing adhesives include silicone adhesives, silylated acrylate adhesives, modified silicone adhesives, polysulfide adhesives, acrylic urethane adhesives, polyurethane adhesives, acrylic adhesives, butyl rubber adhesives, and water glass adhesives, as well as other known adhesives. If the sealing material 3 is a metal plate (steel plate) as described later, it can be attached to the web portion 1a by welding, in which case the welding itself can provide a sealing effect.

[0031] As shown in Figure 1(a), it is preferable that one end of the sealing member 3 protrudes outward from the long-side end face 1c of the flange portion 1b of the steel beam 1.

[0032] Furthermore, it is preferable that the sealing material 3 is in contact with the elongated end face 1c of the upper flange portion 1b. It is also preferable that the sealing material 3 is in contact with the elongated end face 1c of the lower flange portion 1b (the flange portion on the vertical side of the building), and that it covers the lower surface 1d of the flange portion 1b. As a result, the fire-resistant covering structure according to this embodiment has particularly improved airtightness. Such a sealing material 3 can be obtained by processing it to match the shape of the steel beam 1.

[0033] The thickness of the sealing material 3 is not particularly limited and can be in the range of 3 to 100 mm, for example.

[0034] As mentioned above, the sealing material 3 is positioned where it connects to the wall 20, so the number of sealing materials 3 provided on the steel beam is set appropriately according to the number of walls 20.

[0035] The material used to form the sealing material 3 is not particularly limited, but for example, it is preferable to form the sealing material 3 with a fire-resistant material for the purpose of providing fire resistance. The type of fire-resistant material is not particularly limited, but for example, known inorganic boards, concrete materials, cement mortar, and glass fiber reinforced cement are preferred, and specifically, calcium silicate boards, gypsum boards, ALC, GRC, etc. The sealing material 3 may also be a metal plate such as a steel plate. It is preferable that the sealing material 3 be an inorganic board such as a calcium silicate board because there is no need for welding to fix the sealing material 3 to the flange portion 1b, and it is easy to align it with the wall at the construction site (it is easy to connect with the wall).

[0036] The thickness of the sealing material 3 is not particularly limited, but it is preferable that it has a thickness such that the fire-resistant covering material 2 and the sealing material 3 can be connected by fasteners, as described later.

[0037] The fire-resistant covering material 2 is, for example, a plate-shaped member. The fire-resistant covering material 2 is attached to the side end surface 3a and the bottom surface 3b of the sealing material 3 so as to cover the sides and bottom of the steel beam 1. The bottom surface 3b of the sealing material refers to the surface on the vertical side in the room where the steel beam 1 is located.

[0038] The fire-resistant covering material 2, which is bonded to the side end surface 3a of the sealing material 3, is positioned to face the web portion 1a of the steel beam 1 and is provided to cover the entire lateral surface of the steel beam 1. Therefore, the fire-resistant covering material 2 bonded to the side end surface 3a of the sealing material 3 is large enough to cover at least the upper flange portion 1b, the web portion 1a, and the lower flange portion 1b of the steel beam 1. The fire-resistant covering material 2 may be formed in a long length so as to cover the entire lateral surface of the steel beam 1. Alternatively, two or more fire-resistant covering materials 2 can be joined together without gaps to cover the entire lateral surface of the steel beam 1.

[0039] The fire-resistant coating material 2, which is attached to the side end surface 3a of the sealing material 3, is positioned so as to be in contact with the wall 20, as can be seen in Figures 1(a) and 2. As shown in Figure 2, a sealant 50 can be provided between the fire-resistant coating material 2 and the wall 20 to prevent fire extinguishing gases and the like from entering.

[0040] The fire-resistant coating material 2, which is bonded to the lower surface 3b of the sealing material 3, is positioned to face the lower flange portion 1b of the steel beam 1 and is provided to cover the entire lower surface of the steel beam 1. The fire-resistant coating material 2, which is bonded to the lower surface 3b of the sealing material 3, may also be directly bonded to the lower flange portion 1b. Alternatively, as shown in Figure 1(a), if the sealing material 3 covers the lower surface 1d of the flange portion 1b, the fire-resistant coating material 2 does not come into contact with the lower flange portion 1b, and the sealing material 3 is interposed between the fire-resistant coating material 2 and the lower flange portion 1b.

[0041] The fire-resistant covering material 2, which is attached to the lower surface 3b of the sealing material 3, may be formed to be long enough to cover the entire lower surface of the steel beam 1. Alternatively, two or more fire-resistant covering materials 2 can be joined together without gaps to cover the entire lower surface of the steel beam 1. The fire-resistant covering material 2 positioned opposite the lower flange portion 1b of the steel beam 1 is connected to the fire-resistant covering material 2 positioned on the side of the steel beam 1. This connection can be made, for example, with a fastener 40.

[0042] The fire-resistant coating material 2 attached to the side end surface 3a of the sealing material 3 and the fire-resistant coating material 2 attached to the bottom surface 3b of the sealing material 3 may be independent members. Alternatively, the fire-resistant coating material 2 attached to the side end surface 3a of the sealing material 3 and the fire-resistant coating material 2 attached to the bottom surface 3b of the sealing material 3 may be integrated. Specifically, a fire-resistant coating material formed integrally in a U-shape can be attached to the side end surface 3a and the bottom surface 3b of the sealing material 3.

[0043] The fire-resistant coating material 2, which is attached to the lower surface 3b of the sealing material 3, is positioned so as to be in contact with the wall 20, as can be seen in Figures 1(a) and 2. In this case as well, a sealant 50 can be provided between the fire-resistant coating material 2 and the wall 20 to prevent fire extinguishing gases from entering.

[0044] As described above, in the fire-resistant covering structure of this embodiment, the fire-resistant covering material 2 is bonded to both sides and the bottom of the steel beam 1 via sealing material 3. This ensures airtightness of the space between the steel beam 1 and the fire-resistant covering material 2, thereby suppressing the leakage of fire extinguishing gases, etc., into adjacent rooms.

[0045] The fire-resistant coating material 2 is preferably a long, plate-shaped fire-resistant material. The material for forming the fire-resistant coating material 2 is not particularly limited, and for example, known fire-resistant coating materials can be widely used. The type of fire-resistant coating material is not particularly limited, and for example, inorganic boards can be used, as well as metal fibers, inorganic fibers, composite fibers, foamed sheets, etc. Specifically, examples include calcium silicate boards, gypsum boards, composite materials (for example, wrap-around type fire-resistant coating materials) made by laminating a fibrous base material such as nonwoven fabric onto metal fibers such as rock wool, and among these, calcium silicate boards are preferred.

[0046] In other words, both the fire-resistant coating material 2 and the sealing material 3 can be calcium silicate boards. In this case, not only is fire resistance improved, but airtightness against gases, etc., is particularly enhanced, making it especially difficult for fire extinguishing gases, etc., to leak into adjacent rooms, etc.

[0047] It is preferable that a sealing layer 30 is interposed between the fire-resistant coating material 2 and the sealing material 3. In this case, the adhesion between the fire-resistant coating material 2 and the sealing material 3 is strengthened, and the airtightness of the fire-resistant coating structure of this embodiment is further improved.

[0048] The sealing layer 30 can use, for example, a wide range of known sealing adhesives, and the type is not particularly limited. Examples of sealing adhesives include silicone-based adhesives, silylated acrylate-based adhesives, modified silicone-based adhesives, polysulfide-based adhesives, acrylic urethane-based adhesives, polyurethane-based adhesives, acrylic-based adhesives, butyl rubber adhesives, and the like.

[0049] When the fire-resistant coating material 2 is bonded to the sealing material 3, it is preferable that the fire-resistant coating material 2 and the flange portion 1b are not in contact. That is, it is preferable that a gap is formed between the fire-resistant coating material 2 and the flange portion 1b without them being in contact. In this invention, this gap is referred to as the clearance portion, and in Figure 1, this clearance portion is indicated as clearance portion 15.

[0050] In the fire-resistant coating structure according to this embodiment, the clearance portion 15 exists between the elongated end face 1c of the flange portion 1b and the fire-resistant coating material 2, and also between the lower surface 1d of the flange portion 1b and the fire-resistant coating material 2. In this case, where a sealing material 3 is placed, the sealing material 3 is placed in the clearance portion 15. That is, it is preferable that the sealing material 3 is formed to extend into a part of the area of ​​the clearance portion 15. The presence of the sealing material 3 in the clearance portion 15 provides particularly high airtightness to gases, etc., in the fire-resistant coating structure of this embodiment, making it particularly difficult for fire extinguishing gases, etc., to leak into adjacent rooms, etc.

[0051] The length of the clearance portion 15, that is, the shortest distance between the fire-resistant coating material 2 and the long side end face 1c or the bottom surface 1d of the flange portion, is preferably 10 to 100 mm.

[0052] Preferably, the fire-resistant coating material 2 and the side end surface 3a of the sealing material 3 are connected by a fastener 40. In this case, the fire-resistant coating material 2 is firmly attached to the sealing material 3, and the airtightness of the fire-resistant coating structure is easily improved.

[0053] The fastener 40 can be made from a wide range of known materials, such as nails, screws, and bolts.

[0054] The fire-resistant covering structure of this embodiment may include other components as long as it comprises a steel beam 1, a fire-resistant covering material 2, and a sealing material 3.

[0055] The fire-resistant coating structure of this embodiment has high airtightness against gases, making it difficult for fire extinguishing gases to leak into adjacent rooms, etc. Therefore, it can be suitably applied to buildings where the installation of gas fire extinguishing equipment is mandated by the Fire Service Act, for example. Buildings equipped with the fire-resistant coating structure of this embodiment can prevent fire extinguishing gases from leaking into adjacent rooms, etc.

[0056] The method for constructing the fire-resistant covering structure of this embodiment is not particularly limited. For example, with the floor slab 20 installed above the steel beam 1, the sealing material 3 is attached to the web portion 1a of the steel beam 1, and then the fire-resistant covering material 2 is bonded to the sealing material 3 to cover the sides and bottom of the steel beam 1, and then the wall 20 is installed. This allows the fire-resistant covering structure of this embodiment to be constructed.

[0057] In identifying the inventions contained herein, the components (properties, structures, functions, etc.) described in each embodiment of this disclosure may be combined in any way. That is, this disclosure encompasses all subject matter consisting of any combination of the combinatable components described herein. [Examples]

[0058] The present invention will be described more specifically below with reference to examples, but the present invention is not limited to the embodiments of these examples.

[0059] (Example 1) A fire-resistant covering structure as shown in Figure 1 was constructed. Specifically, an H-shaped steel beam 1 was prepared, having a web portion 1a and a pair of flange portions 1b formed at both ends of the web portion 1a. The total length of the steel beam 1 was 1500 mm, the height of the web portion 1a (length between the pair of flange portions 1b) was 374 mm, and the width of the flange portions 1b was 200 mm. After attaching the floor slab 10 to the upper flange portion 1b of the steel beam 1, a calcium silicate board (thickness 35 mm x height 485 mm x width 150 mm) was prepared as a sealing material 3, and the sealing material 3 was attached perpendicularly to both sides of the web portion 1a at the midpoint in the longitudinal direction of the steel beam 1 using a water glass adhesive. Both of the sealing materials 3 (calcium silicate boards) were pre-cut to a shape that could cover the longitudinal end faces 1c of the upper flange portion 1b and the lower flange portion 1b, and the lower surface 1d of the lower flange portion 1b.

[0060] Next, two types of calcium silicate boards, A (15 mm thick x 500 mm wide x 1200 mm long) and B (15 mm thick x 300 mm wide x 1200 mm long), were prepared as fire-resistant covering material 2. Calcium silicate board A was bonded to the side end surface 3a of the sealing material 3, and calcium silicate board B was bonded to the bottom surface 3b of the sealing material 3. In this bonding process, a sealing adhesive was interposed between the fire-resistant covering material 2 and the sealing material 3 to form a sealing layer 30. Subsequently, the fire-resistant covering material 2 and the sealing material 3 were connected by fasteners 40 by nailing them from the outside of the fire-resistant covering material 2 bonded to the sealing material 3. Next, a wall 20 was installed so as to meet the pair of sealing materials 3, and the joint between the fire-resistant covering material 2 and the wall 20 was sealed with sealant 50. In this way, the fire-resistant covering structure shown in Figure 1 was formed, and the space between the fire-resistant covering material 2 and the steel beam 1 was made airtight.

[0061] In this fire-resistant coating structure, the distance between the long-side end face 1c of the flange portion 1b and the fire-resistant coating material 2 is 50 mm (i.e., the clearance portion is 50 mm), and the distance between the lower surface 1d of the flange portion 1b and the fire-resistant coating material 2 is 85 mm (i.e., the clearance portion is 85 mm).

[0062] (Comparative Example 1) A fire-resistant covering structure as shown in Figure 3 was constructed. Specifically, an H-shaped steel beam 1 was prepared, having a web portion 1a and a pair of flange portions 1b formed at both ends of the web portion 1a. The total length of the steel beam 1 was 1500 mm, the height of the web portion 1a was 374 mm, and the width of the flange portion 1b was 200 mm. After attaching the floor slab 10 to the upper flange portion 1b of the steel beam 1, a steel plate (thickness 6 mm x height 374 mm x width 96 mm) was prepared as a sealing material 3 and attached perpendicularly to the web portion 1a by welding at the midpoint of the length of the steel beam 1. The outer end of the sealing material 3 was not to protrude outward beyond the outer end of the flange portion 1b. Specifically, the dimensions of the sealing material 3 were adjusted so that the outer end of the sealing material 3 and the side ends of the pair of flange portions 1b were on the same plane (i.e., no clearance was provided).

[0063] Next, two types of calcium silicate boards, A (15 mm thick x 500 mm wide x 1200 mm long) and B (15 mm thick x 300 mm wide x 1200 mm long), were prepared as fire-resistant covering material 2. Calcium silicate board A was bonded to the side end surface 3a of the sealing material 3, and calcium silicate board B was directly bonded to the underside of the lower flange portion 1b (no sealing layer 30 was provided on either calcium silicate board). Next, a wall 20 was installed so as to meet the pair of sealing materials 3, and sealing 50 was applied to the joint between the fire-resistant covering material 2 and the wall 20. In this way, the fire-resistant covering structure shown in Figure 3 was formed, and the space between the fire-resistant covering material 2 and the steel beam 1 was made airtight.

[0064] (Comparative Example 2) A fire-resistant covering structure as shown in Figure 3 was constructed. Specifically, an H-shaped steel beam 1 was prepared, having a web portion 1a and a pair of flange portions 1b formed at both ends of the web portion 1a. The total length of the steel beam 1 was 1500 mm, the height of the web portion 1a was 374 mm, and the width of the flange portion 1b was 200 mm. After attaching the floor slab 10 to the upper flange portion 1b of the steel beam 1, a steel plate (thickness 6 mm x height 374 mm x width 96 mm) was prepared as a sealing material 3 and attached perpendicularly to the web portion 1a by welding at the midpoint in the longitudinal direction of the steel beam 1. The outer end of the sealing material 3 was not to protrude outward beyond the outer end of the flange portion 1b. Specifically, the dimensions of the sealing material 3 were adjusted so that the outer end of the flange portion 1b abutted against the surface passing through the outer end of the sealing material 3 (i.e., no clearance was provided). No sealing material 3 was provided on the lower surface 1d of the flange portion 1b.

[0065] Next, felt (20 mm thick, 1200 mm long, Nichias Corporation "Makibee" (registered trademark)) was prepared as the fire-resistant covering material 2, and the felt was attached to cover both sides of the upper flange portion 1b and the lower flange portion 1b, as well as the underside of the lower flange portion 1b. The felt was also made to be in contact with the pair of sealing members 3. Next, a wall 20 was installed so as to connect with the pair of sealing members 3, and the joint between the fire-resistant covering material 2 and the wall 20 was sealed with sealant 50. In this way, the fire-resistant covering structure shown in Figure 3 was formed, and the space between the fire-resistant covering material 2 and the steel beam 1 was made airtight.

[0066] (Evaluation method) An airtightness test of the fire-resistant coating structure obtained in the example was conducted using the evaluation apparatus shown in Figure 4. Specifically, as shown in Figure 4, a space surrounding the steel beam 1 to which the sealing material 3 and fire-resistant coating material 2 were attached was formed by plywood 80 and floor slab 10, and the steel beam 1 to which the sealing material 3 and fire-resistant coating material 2 were attached was placed within this space (note that the wall 20 is not shown in Figure 4). The volume of the space S enclosed by plywood 80 and floor slab 10 was 0.54 m³. 3The dimensions were set to (750mm × 600mm × 1200mm). Nitrogen gas was flowed into this space S at a constant flow rate (15L / min, 30L / min, and 50L / min) for 3 minutes, and the pressure rise in the space was measured. The same evaluation apparatus was assembled and the pressure rise in the space was measured for the fire-resistant coating structures formed in Comparative Examples 1 and 2 using the same method.

[0067] Table 1 shows the pressure increase results for the fire-resistant coating structures formed in each example and comparative example.

[0068] As shown in Table 1, the fire-resistant coating structure formed in Example 1 showed a greater pressure increase compared to the fire-resistant coating structures of Comparative Examples 1 and 2. Therefore, it was demonstrated that the fire-resistant coating structure formed in Example 1 has higher airtightness than the fire-resistant coating structures of Comparative Examples 1 and 2.

[0069] [Table 1] [Explanation of Symbols]

[0070] 1: Steel beam 1a: Web Department 1b: Flange section 1c: Long side end surface 1d: Lower surface of flange 2: Fireproof covering material 3: Sealing material 3a: Side end face of the sealing material 3b: Bottom surface of the sealing material 15: Clearance section 10: Floor slab 20: Wall 30: Sealing layer 40: Fixtures 50: Ceiling 80: Plywood S: Space

Claims

1. A fire-resistant covering structure for steel beams installed to penetrate a wall, It consists of steel beams, fire-resistant covering material, and sealing material. The steel beam has a long web portion and a pair of flange portions formed at both ends of the web portion. The aforementioned sealing material is provided in the web portion and is positioned at a location where it interacts with the wall. The fire-resistant covering material is attached to the side end surface and bottom surface of the sealing material and is provided to cover the sides and bottom of the steel beam. A fire-resistant covering structure for a steel beam, wherein a sealing layer is interposed between the fire-resistant covering material and the sealing material.

2. The fire-resistant covering structure for a steel beam according to claim 1, wherein a clearance is formed between the fire-resistant covering material and the flange portion without contact.

3. The fire-resistant covering structure for a steel beam according to claim 1, wherein the fire-resistant covering material and the side end surface of the sealing material are connected by a fastener.

4. The fire-resistant covering material is a plate-shaped fire-resistant material formed in a long length, as described in claim 1, for the fire-resistant covering structure of a steel beam.

5. The fire-resistant covering structure for a steel beam according to claim 1, wherein the fire-resistant covering material is a calcium silicate board.

6. The fire-resistant covering structure for a steel beam according to claim 1, wherein the sealing material is a calcium silicate board.

7. A building comprising a fire-resistant covering structure for steel beams as described in any one of claims 1 to 6.

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