Fire-resistant covering structure and method of constructing the same

Abstract

To provide a fire-resistant covering structure suitable as a dew condensation countermeasure for a composite fire-resistant structure of a column and a beam, and its construction method.SOLUTION: In a fire-resistant covering structure 10 comprising a fire-resistant covering material 16 continuously provided from the outside of a steel column or a steel beam 14 oppositely arranged in proximity to a wall body 12 to the surface of the wall body 12, a moisture-proof film 18 which is provided on the outside of the fire-resistant covering material 16 in order to suppress the transmission of steam W from the outside to the inside of the fire-resistant covering material 16 and whose moisture permeability resistance is higher than that of the fire-resistant covering material 16 is further provided.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a fire-resistant covering structure having a moisture-proof function and a construction method thereof. [Background technology]

[0002] Conventionally, when steel beams or columns are installed near the exterior walls of steel-framed buildings, the fireproof covering of the steel frame is often made into a composite fireproof structure with the exterior wall. The reason for adopting a composite fireproof structure is that the close proximity of the exterior wall to the steel frame makes it extremely difficult to apply the fireproof covering to the exterior side of the steel frame.

[0003] Since the exterior walls of synthetic fire-resistant structures do not usually have insulation or other measures in place to prevent condensation, in cold regions or buildings with high indoor humidity, such as IDCs, hospitals, homes, and hotels, large amounts of condensation can form on the exterior walls and cause actual damage.

[0004] Condensation in a composite fireproof structure occurs when, for example, water vapor W generated indoors by heating, etc., penetrates through the fireproof coating material 2 that covers the steel beams 1, penetrates into the interior 3 of the composite fireproof structure, and reaches the dew point on the inner surface of the exterior wall 5 that is cooled by the outside air 4, as shown in Figure 6. For this reason, it is thought that this condensation can be suppressed if the fireproof coating material 2 can ensure moisture permeability resistance. However, there are no construction methods using fireproof coating materials currently on the market that can maintain sufficient moisture permeability resistance to prevent condensation. In Figure 6, the reference numeral 6 denotes a foamed plastic insulation material for preventing condensation. In a composite fireproof structure, applying such insulation to the inner surface of the exterior wall 5 is not permitted as it would result in the structure being ineligible for fireproofing.

[0005] Conventional countermeasures against condensation in synthetic fire-resistant structures include, for example, applying urethane foam on the surface of fire-resistant covering materials. However, in harsh environments such as parapets, the moisture permeability resistance may not be sufficient to prevent condensation. In addition, the boundary between the area requiring moisture-proofing and other areas while maintaining the fire-resistant performance is not established, making it necessary to take moisture-proofing measures over a wide area.

[0006] In addition, other dew condensation prevention techniques in fire-resistant coating structures are known, for example, as described in Patent Documents 1 and 2. Patent Document 1 relates to a fire-resistant coating structure having a dew condensation prevention function that prevents dew condensation on the surface of a member such as a steel frame, improves water resistance, maintains fire resistance, and allows for decorative finishing. This fire-resistant coating structure has a foaming fire-resistant paint layer formed from a foaming fire-resistant paint on the surface of the structure from the structure side, and a dew condensation prevention paint layer formed from a dew condensation prevention paint. In addition, Patent Document 2 relates to a fire-resistant coating structure for a steel beam that can improve the heat insulation performance and airtightness performance around the steel beam while ensuring the fire resistance of the steel beam. This fire-resistant coating structure includes a heat-expandable fire-resistant coating sheet layer that covers the exposed portion of the outer periphery of the steel beam that does not face or abut against the exterior wall or floor, an airtight layer of a metal film that covers the surface of the fire-resistant coating sheet layer, and an insulating layer mainly made of a phenolic resin foam that is provided between the exposed portion and the fire-resistant coating sheet layer. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2001-200597 A [Patent Document 2] JP 2010-43444 A Summary of the Invention [Problem to be solved by the invention]

[0008] As mentioned above, there was a demand for an appropriate dew condensation prevention method for the composite fireproof structure of columns and beams. There was also a demand for the establishment of a technology to contain the boundary between the area requiring moisture prevention measures and the other areas while maintaining the continuity of fire resistance.

[0009] The present invention has been made in view of the above, and an object of the present invention is to provide a fire-resistant covering structure suitable as a measure against condensation in a composite fire-resistant structure of columns and beams, and a construction method thereof. [Means for solving the problem]

[0010] In order to solve the above-mentioned problems and achieve the object, the fire-resistant covering structure of the present invention is a fire-resistant covering structure comprising a fire-resistant covering material continuously provided from the outside of a steel column or steel beam arranged adjacent to and facing a wall to the surface of the wall, and further comprising a moisture-proof film provided on the outside of the fire-resistant covering material to suppress the transmission of water vapor from the outside to the inside of the fire-resistant covering material, and having a moisture permeability resistance higher than the moisture permeability resistance of the fire-resistant covering material.

[0011] In addition, another fire-resistant coating structure according to the present invention is characterized in that, in the above-mentioned invention, the moisture-proof film is continuously provided across the small edge portion of the end of the inorganic fire-resistant coating material that requires moisture-proofing measures and the portion adjacent to the end of the inorganic fire-resistant coating material that does not require moisture-proofing measures.

[0012] Further, another fire-resistant covering structure according to the present invention is characterized in that, in the above-mentioned invention, the moisture-proof film is composed of a film or sheet containing a polyester-based material or an aluminum-based material as a main material.

[0013] In addition, the method for constructing a fire-resistant covering structure according to the present invention is a method for constructing the above-mentioned fire-resistant covering structure, characterized in that a sheet-shaped fire-resistant covering material is manufactured by providing a moisture-proof film on the outside of a sheet-shaped inorganic fire-resistant covering material, and then this sheet-shaped fire-resistant covering material is attached from the outside of a steel column or steel beam to the surface of a wall. Effect of the Invention

[0014] The fire-resistant covering structure of the present invention is provided with a fire-resistant covering material that is continuously provided from the outside of a steel column or steel beam that is arranged adjacent to and facing a wall to the surface of the wall, and further includes a moisture-proof film that is provided on the outside of the fire-resistant covering material to suppress the transmission of water vapor from the outside to the inside of the fire-resistant covering material and has a moisture-proof property with a moisture permeation resistance higher than that of the fire-resistant covering material, thereby achieving the effect of suppressing the occurrence of condensation in the composite fire-resistant structure of the columns and beams.

[0015] In addition, according to another fire-resistant coating structure of the present invention, the moisture-proof film is continuously provided across the small edge portion of the end of the inorganic fire-resistant coating material that requires moisture-proofing measures and the portion adjacent to the end of the inorganic fire-resistant coating material that does not require moisture-proofing measures, thereby achieving the effect of separating the portion that requires moisture-proofing measures from other portions while maintaining continuity of fire-resistant performance.

[0016] In addition, according to another fire-resistant coating structure of the present invention, the moisture-proof film is composed of a film or sheet containing a polyester-based material or an aluminum-based material as a main material, thereby achieving the effect of ensuring moisture-proofing while reducing construction costs.

[0017] Furthermore, according to the method for constructing a fire-resistant covering structure of the present invention, a sheet-like fire-resistant covering material is manufactured by providing a moisture-proof film on the outside of a sheet-like inorganic fire-resistant covering material, and then this sheet-like fire-resistant covering material is attached from the outside of a steel column or steel beam to the surface of a wall, thereby achieving the effect of easily constructing a structure that ensures fire resistance at the boundary between the part requiring moisture-proofing measures and the other parts in a composite fire-resistant structure of columns and beams. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is a cross-sectional view showing an embodiment of a fire-resistant covering structure and its construction method according to the present invention, in which (1) is an example of boundary fitting around a steel beam, and (2) is an example of boundary fitting between a moisture-proof specification and a general specification. [Diagram 2] Figure 2 compares the changes in actual measured values ​​over time, where (1) is the amount of water vapor, (2) is the temperature, and (3) is the humidity. [Diagram 3] FIG. 3 is a cross-sectional view showing an example of fitting of a composite fireproof structure of steel beams according to this embodiment. [Figure 4] FIG. 4 is a cross-sectional view showing an example of fitting of a composite fireproof structure of a steel column according to this embodiment. [Diagram 5]FIG. 5 is a cross-sectional view showing an example of an end moisture-proofing treatment according to the present embodiment. [Figure 6] FIG. 6 is a cross-sectional view showing an example of a conventional composite fire-resistant structure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of a fire-resistant covering structure and a method for constructing the same according to the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to these preferred embodiments.

[0020] As shown in Fig. 1 (1), a fire-resistant covered structure 10 according to an embodiment of the present invention is applied to a steel beam 14 arranged adjacent to an exterior wall 12 (wall body) that separates an interior space A from an exterior space B. This fire-resistant covered structure 10 comprises an interior-side surface of the steel beam 14 and an inorganic fire-resistant covering material 16 that is continuously provided from this surface to the interior surface of the exterior wall 12. A moisture-proof film 18 is provided on the outer surface of the fire-resistant covering material 16.

[0021] The exterior wall 12 can be made of, for example, extruded cement board (ECP). The steel beam 14 is made of H-shaped steel having a web 20 and upper and lower flanges 22, 24. A floor deck 26 is provided on the upper surface of the upper flange 22 of the steel beam 14. An interlayer seal 28 (interlayer partition material) is provided between the floor deck 26 and the exterior wall 12. An insulating material 30 for preventing condensation is provided on the upper side of this interlayer seal 28 and on the inner surface of the exterior wall 12 below the fire-resistant covering structure 10. The insulating material 30 can be made of, for example, a foamed plastic insulating material. The insulating material 30 is not essential and may be omitted. An interior material 32 is provided on the indoor side at a distance from the insulating material 30. A ceiling base material 34 and a ceiling material 36 are provided below the lower flange 24 of the steel beam 14.

[0022] The fireproof coating material 16 can be constructed using an inorganic fireproof coating material such as sprayed rock wool. In this embodiment, it is assumed that the inorganic fireproof coating material 16 is formed into a sheet. The moisture-proof film 18 is for suppressing the permeation of water vapor W from the outside to the inside of the fireproof coating material 16, and can be constructed, for example, of a film or sheet containing a polyester-based material as a main material, such as a polyester-based moisture-proof film or sheet. By using such a material, it is possible to ensure moisture resistance and reduce construction costs. However, the moisture-proof film 18 is not limited to this, and any moisture-proof film or sheet having a moisture permeation resistance higher than that of the fireproof coating material 16 may be used. Examples of such a film or sheet include a film or sheet containing, as a main material, a rubber-based material, an aluminum-based material such as aluminum foil, other film materials, urethane foam, etc., in addition to a polyester-based material. By providing the moisture-proof film 18 on the outer surface of the fireproof coating material 16, it is possible to prevent the water vapor W in the room A from condensing on the inner surface of the exterior wall 12.

[0023] When constructing this fire-resistant covered structure 10, first, a sheet-like inorganic fire-resistant covering material 16 is prepared. Next, a moisture-proof film 18 is provided on the outer surface of this fire-resistant covering material 16 to produce a sheet-like fire-resistant covering material. This sheet-like fire-resistant covering material is then attached from the outside of the steel beams 14 to the surface of the exterior wall. In this manner, the fire-resistant covered structure 10 can be easily constructed. As a method for providing the moisture-proof film to the fire-resistant covering material, for example, a method of attaching it via an adhesive or the like can be used.

[0024] The operation and function of the above configuration will now be described. Although the inorganic fire-resistant coating material 16 has low moisture permeability resistance and allows water vapor W on the indoor side to pass through, the transmission of water vapor W on the indoor side is suppressed by providing a moisture-proof film 18 with high moisture permeability resistance on the surface of the fire-resistant coating material 16. By reducing the amount of water vapor W penetrating into the interior 38 of the composite fire-resistant structure formed by the fire-resistant coating structure 10, the dew point temperature of the air inside 38 of the composite fire-resistant structure is lowered and the occurrence of condensation is reduced.

[0025] Therefore, according to this embodiment, it is possible to suppress the occurrence of condensation inside 38 of the composite fireproof structure of steel beams 14. Also, since construction is possible only in areas where moisture-proofing measures are required (such as only on the exterior wall side), the sheet-like fireproof covering material 16 without the moisture-proof film 18 can be used in areas where other moisture-proofing measures are not required.

[0026] In addition, in rooms subject to interior design restrictions under the Building Standards Act (rooms where the surface material must be non-combustible or semi-non-combustible), the moisture-proof function of the fireproof coating material can be guaranteed on the surface (without ceiling). This makes it highly valuable in rooms where ceilings are not normally installed, such as machine rooms and warehouses.

[0027] In the above embodiment, the steel beam is an H-shaped steel beam, but the present invention is not limited to this, and any steel material that can be used for a steel beam may be used. For example, the steel beam may be made of steel material having a different cross-sectional shape. In this case, the same effect as the above can be obtained.

[0028] (Verification of the Effects of the Invention) Next, a demonstration experiment conducted to verify the effects of the present invention will be described.

[0029] In this experiment, the fireproof covering structure according to the present invention was constructed under conditions close to those of actual construction, and its workability and moisture-proofing were confirmed. Specifically, a sheet-shaped fireproof covering material with a moisture-proof film was constructed on the pillars and beams of an actual building. A wrapped fireproof covering material made of heat-resistant rock wool felt was used as the fireproof covering material. As a result, it was confirmed that the fireproof covering material could be constructed without gaps at its ends. After that, the outer periphery of the synthetic fireproof structure of this embodiment was covered with a vinyl sheet, and the temperature and humidity were measured while humidifying the inside of the vinyl sheet, and the moisture-proofing effect was confirmed. In addition, as a comparative example, a synthetic fireproof structure constructed with a sheet-shaped fireproof covering material without a moisture-proof film was also covered with a vinyl sheet in the same manner to confirm its moisture-proofing effect.

[0030] The results of the actual measurements are shown in Figure 2. In the figure, the Example (inside vinyl) and Comparative Example (inside vinyl) are the measurements taken inside the vinyl sheet. As shown in this figure, by applying a sheet-type fireproof covering material with a moisture-proof film, the water vapor pressure inside the composite fireproof structure is reduced, and the occurrence of condensation can be suppressed and reduced.

[0031] (Example of boundary between moisture-proof and general specifications) Next, an example of the boundary between the moisture-proof specification and the general specification will be described. As shown in FIG. 1(2), this arrangement is such that inorganic fireproof coating material 16 is divided into a moisture-proof specification that requires moisture-proofing measures and a general specification that does not require moisture-proofing measures on the indoor-side surface of steel beams 14 and exterior wall 12. Moisture-proof film 18 is provided at the boundary between them. Specifically, moisture-proof film 18 is continuously provided in a substantially Z-shape in cross section from the front side of moisture-proof fireproof coating material 16 through the small end portion to the back side of general specification fireproof coating material 16. In this way, it is possible to separate the part that requires moisture-proofing measures from the other parts while maintaining a continuous fire-resistance performance.

[0032] (Example of fitting of composite fireproof structure of steel beams) Next, an example of how the steel beams 14 are fitted into the composite fireproof structure will be described. As shown in FIG. 3, this arrangement is such that a sheet-like inorganic fireproof coating material 16 with a moisture-proof film 18 is continuously provided on the inner surface of the exterior wall 12 from the end of the upper flange 22 of the steel beam 14 through the end of the lower flange 24. The upper end 40 of the fireproof coating material 16 is bent outward. This bent portion is fixed to the upper flange 22 by a fixing pin 42 with an insulating material by welding or the like. The periphery of the end 40 of the fireproof coating material 16 is sealed with a moisture-proof tape 48. Specifically, the moisture-proof tape 48 is continuously applied from the vicinity of the end 40 of the fireproof coating material 16 to the floor deck 26 so as to straddle the head and end 40 of the fixing pin 42. The moisture-proof tape 48 can be made of the same material as the moisture-proof film 18.

[0033] The lower end 44 of the fire-resistant covering material 16 is bent and positioned so as to fit along the lower and inner surfaces of a base material 46 made of L-shaped steel fixed to the inner surface of the exterior wall 12. This end 44 extends to a position below the base material 14 and is fixed to the inner surface of the base material 46 by welding or the like with a fixing pin 42 with an insulating material. In addition, the periphery of the end 44 of the fire-resistant covering material 16 is sealed with a moisture-proof tape 48. Specifically, the moisture-proof tape 48 is continuously applied from the vicinity of the end 44 of the fire-resistant covering material 16 to the inner surface of the exterior wall 12 so as to straddle the head and end 44 of the fixing pin 42.

[0034] The fireproof covering material 16 is fixed to the lower surface of the lower flange 24 by welding or the like using fixing pins 42 with insulating material. The heads of the fixing pins 42 are sealed with moisture-proof tape 48 or the like. The upper corners of the interlayer plug 28 are also sealed with moisture-proof tape 48 or the like.

[0035] According to the above-mentioned arrangement, the moisture-proof tape 48 seals gaps that occur around the ends of the fire-resistant covering material 16 and the fixing pins 42, and also suppresses the occurrence of condensation inside the composite fire-resistant structure.

[0036] (Example of fitting of composite fireproof structure of steel columns) Next, an example of the fit of the composite fire-resistant structure of steel columns will be described. As shown in FIG. 4, this arrangement is applied to a steel column 50 arranged close to and facing the exterior wall 12. The steel column 50 is made of H-shaped steel. A sheet-like inorganic fireproof coating material 16 equipped with a moisture-proof film 18 is provided around the outer periphery of the steel column 50, except for the surface facing the exterior wall 12. This fireproof coating material 16 is provided continuously from the steel column 50 to the inner surface of the exterior wall 12 in a substantially U-shaped shape in a plan view. The end of the fireproof coating material 16 is bent outward along the inner surface of the exterior wall 12, and is fixed to the inner surface of the exterior wall 12 by a fixing pin 42 with an insulating material. The fireproof coating material 16 is fixed to the outer flange of the steel column 50 by welding or the like with the fixing pin 42 with an insulating material. The heads of these fixing pins 42 are sealed with a moisture-proof tape 48 or the like.

[0037] According to the above-mentioned arrangement, the moisture-proof tape 48 closes the gaps around the fixing pins 42 and suppresses the occurrence of condensation inside the composite fireproof structure. In the above, the steel frame column 50 is made of H-shaped steel, but the steel frame column 50 may be made of a steel pipe column such as a square steel pipe. In this case, the same effect as above can be achieved.

[0038] (Example of moisture-proofing treatment for edges) Next, a specific example of moisture-proofing treatment for the ends of the fire-resistant covering material 16 will be described. A in Fig. 5 is an example where the end is treated with moisture-proof tape 48 and urethane foam 52, and B in Fig. 5 is an example where the end is treated only with urethane foam 52. A corresponds to a high-grade specification with high moisture-proof performance, B corresponds to a low-grade specification with low moisture-proof performance, and A omitting urethane foam 52 corresponds to a medium-grade specification in between. Note that in each figure, beam 1 indicates the case where the steel beam 14 and floor deck 26 are perpendicular to each other, beam 2 indicates the case where the steel beam 14 and floor deck 26 are parallel to each other, and beam 3 and column indicate the joint with the exterior wall 12.

[0039] As shown in A of FIG. 5, after the moisture-proof tape 48 is continuously applied so as to straddle each end of the fire-resistant covering material 16 having the moisture-proof film 18 on the outside, the urethane foam 52 is applied thereon. The moisture-proof tape 48 can be made of the same material as the moisture-proof film 18. In this way, the moisture-proof tape 48 is continuously applied across the small end portion of the inorganic fire-resistant covering material 16 that requires moisture-proofing measures and the portion adjacent to the end of the inorganic fire-resistant covering material 16 that does not require moisture-proofing measures, so that the fire resistance performance can be ensured at the boundary between the portion that requires moisture-proofing measures and the other portion. In addition, if the urethane foam 52 is omitted in A, the moisture-proof performance can be made medium grade. Also, as shown in B of FIG. 5, if the application of the moisture-proof tape 48 is omitted and the end portion is treated only with the urethane foam 52, the moisture-proof performance can be made low grade. In this way, it is possible to use the moisture-proof performance (high, medium, low) according to the required grade.

[0040] According to the above configuration, it is possible to achieve a fit that ensures fire resistance at the boundaries between areas requiring condensation countermeasures (moisture prevention) and other areas, making it possible to carry out construction that limits moisture prevention measures to the necessary area.

[0041] As described above, the fire-resistant covering structure of the present invention is a fire-resistant covering structure comprising a fire-resistant covering material that is continuously provided from the outside of a steel column or steel beam that is arranged adjacent to and facing a wall to the surface of the wall, and further comprises a moisture-proof film that is provided on the outside of the fire-resistant covering material in order to suppress the transmission of water vapor from the outside to the inside of the fire-resistant covering material and has a moisture permeability resistance higher than that of the fire-resistant covering material, thereby making it possible to suppress the occurrence of condensation in the composite fire-resistant structure of the columns and beams.

[0042] In addition, according to another fire-resistant coating structure of the present invention, the moisture-proof film is continuously provided across the small edge portion of the end of the inorganic fire-resistant coating material that requires moisture-proofing measures and the portion adjacent to the end of the inorganic fire-resistant coating material that does not require moisture-proofing measures, thereby making it possible to separate the portion that requires moisture-proofing measures from other portions while maintaining continuity of fire-resistant performance.

[0043] In addition, according to another fire-resistant coating structure of the present invention, the moisture-proof film is composed of a film or sheet containing a polyester-based material or an aluminum-based material as a main material, thereby ensuring moisture resistance while reducing construction costs.

[0044] Furthermore, according to the method for constructing a fire-resistant covering structure of the present invention, a sheet-like fire-resistant covering material is manufactured by providing a moisture-proof film on the outside of a sheet-like inorganic fire-resistant covering material, and then this sheet-like fire-resistant covering material is attached from the outside of a steel column or steel beam to the surface of a wall, so that a structure that ensures fire resistance at the boundary between the part requiring moisture-proofing measures and the other parts in a composite fire-resistant structure of columns and beams can be easily constructed. [Industrial Applicability]

[0045] INDUSTRIAL APPLICABILITY As described above, the fire-resistant covering structure and its construction method according to the present invention are useful for fire-resistant covering of composite fire-resistant structures of columns and beams, and are particularly suitable for suppressing the occurrence of condensation inside the composite fire-resistant structure. [Explanation of symbols]

[0046] 10 Fire-resistant coating structure 12 Exterior wall (wall) 14 Steel beam 16 Fireproof cladding 18 Moisture-proof film 20 Web 22 Upper flange 24 Bottom flange 26 Floor Deck 28 Layer sealing 30 Insulation 32 Interior materials 34 Ceiling underlayment 36 Ceiling materials 38 Internal 40,44 End 42 Fixing pin 46 Base material 48 Moisture-proof tape 50 Steel column 52 Urethane foam A Indoor B Outdoors

Claims

1. A fire-resistant covering structure comprising a fire-resistant covering material continuously provided from the outside of a steel column or steel beam arranged adjacent to and facing a wall body to a surface of the wall body, the fire-resistant covering structure further comprising a moisture-proof material provided on the outside of the fire-resistant covering material in order to suppress the transmission of water vapor from the outside to the inside of the fire-resistant covering material, the moisture-proof material having a moisture permeability resistance higher than the moisture permeability resistance of the fire-resistant covering material, A fire-resistant coating structure characterized in that the moisture-proof material is continuously provided from the front side of the inorganic fire-resistant coating material that requires moisture-proofing measures, through the small end portion, to the back side of the inorganic fire-resistant coating material that does not require moisture-proofing measures.

2. A method for applying the fire-resistant coating structure of claim 1, comprising the steps of: A method for constructing a fire-resistant covering structure, comprising the steps of: producing a sheet-like fire-resistant covering material by providing the moisture-proof material on the outside of the sheet-like inorganic fire-resistant covering material; and then attaching the sheet-like fire-resistant covering material from the outside of the steel column or steel beam to the surface of the wall.

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