JP7613898B2 - Fireproof coating construction method - Google Patents

Description

Application of Article 30, Paragraph 2 of the Patent Act 2020 Architectural Institute of Japan Conference Academic Lecture Abstracts Publication date: July 20, 2020

The present invention relates to a fire-resistant coating structure with moisture-proofing function and a construction method thereof.

Traditionally, when steel beams or columns are installed near the exterior walls of a steel-framed building, the fireproof coating 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 proximity of the exterior wall to the steel frame makes it extremely difficult to apply fireproof coating to the exterior side of the steel frame.

Due to fire-resistance certification, insulation materials to prevent condensation cannot be installed on the exterior walls of synthetic fire-resistant structures, so in cold regions or buildings with high indoor humidity, such as IDCs, hospitals, homes, and hotels, large amounts of condensation can occur on the exterior walls and cause actual damage.

Condensation in a composite fireproof structure occurs when, for example, water vapor W generated on the room A side by heating, etc., penetrates 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 3. 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 fireproof coating materials currently on the market that have sufficient moisture permeability resistance to prevent condensation. In Figure 3, the reference numeral 6 denotes a foamed plastic insulation material for preventing condensation. In a composite fireproof structure, such insulation cannot be installed on the inner surface of the exterior wall 5 due to fireproof certification.

Conventional methods for preventing condensation in synthetic fireproof structures include using wrapped rockwool felt with a moisture-proof layer, such as Makibee with Moisture-Proof Layer ("Makibee" is a registered trademark), and applying in-situ foamed urethane to the surface of the fireproof coating material. However, wrapped rockwool felt with a moisture-proof layer is a dry construction method, which means that the workability of moisture-proofing treatment at the ends of the fireproof coating material and at the joints with members that penetrate the fireproof coating is poor, and in-situ foamed urethane does not have sufficient moisture permeability resistance to prevent condensation, and both methods have problems in terms of practicality and quality assurance.

Another known technique for preventing condensation in fire-resistant coating structures is described in, for example, Patent Document 1. Patent Document 1 relates to a fire-resistant coating structure that can improve the heat insulation and airtightness around a steel column while ensuring the fire resistance of the steel column that faces a non-combustible exterior wall. 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 column that does not face the exterior wall, an airtight layer of metal film that covers the surface of the fire-resistant coating sheet layer, and an insulating layer made primarily of phenolic resin foam that is provided between the exposed portion of the steel column and the fire-resistant coating sheet layer.

JP 2010-43445 A

As mentioned above, there was a need for an appropriate method of preventing condensation in composite fire-resistant structures of columns and beams. There was also a need for technology that could form a stable moisture-proof layer without gaps at the ends of fire-resistant coating materials and at the joints with components that penetrate the fire-resistant coating.

The present invention has been made in consideration of the above, and aims to provide a fire-resistant coating structure suitable for preventing condensation in composite fire-resistant structures of columns and beams, and a construction method thereof.

In order to solve the above problems and achieve the object, the fire-resistant coating structure according to the present invention is a fire-resistant coating structure comprising an inorganic fire-resistant coating 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 an organic coating material that is provided on the outside of the inorganic fire-resistant coating material to suppress the transmission of water vapor from the outside to the inside of the inorganic fire-resistant coating material and has a moisture permeability resistance higher than that of the inorganic fire-resistant coating material.

In addition, another fire-resistant coating structure according to the present invention is characterized in that in the above-mentioned invention, the organic coating material is composed of a material whose main component is any of the following: modified asphalt-based waterproofing material, asphalt-based emulsion moisture-proofing material, water-soluble acrylic-based waterproofing material, ultra-fast-curing urethane waterproofing material, highly elastic acrylic rubber-based wall waterproofing decorative material, ultra-low-pollution NAD elastic polyurethane resin paint, and ultra-low-pollution water-based elastic fluororesin paint.

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, and is characterized in that a sheet-like fire-resistant covering material is manufactured by providing an organic coating material 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.

Another method for constructing a fire-resistant coating structure according to the present invention is characterized in that, in the above-mentioned invention, a sheet-shaped fire-resistant coating material is produced by spraying an organic coating material onto the outside of a sheet-shaped inorganic fire-resistant coating material.

Another 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-like inorganic fire-resistant covering material is attached from the outside of the steel column or steel beam to the surface of the wall, and then an organic coating material is sprayed onto the outside of the sheet-like inorganic fire-resistant covering material.

The fire-resistant coating structure according to the present invention is a fire-resistant coating structure that includes an inorganic fire-resistant coating 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 an organic coating material that is provided on the outside of the inorganic fire-resistant coating material to suppress the transmission of water vapor from the outside to the inside of the inorganic fire-resistant coating material and has a moisture permeability resistance higher than that of the inorganic fire-resistant coating material, thereby achieving the effect of suppressing the occurrence of condensation in the composite fire-resistant structure of the columns and beams.

In addition, according to another fire-resistant coating structure of the present invention, the organic coating material is composed of a material whose main component is any of the following: modified asphalt-based waterproofing material, asphalt-based emulsion moisture-proofing material, water-soluble acrylic-based waterproofing material, ultra-fast-curing urethane waterproofing material, highly elastic acrylic rubber-based wall waterproofing decorative material, ultra-low-pollution NAD elastic polyurethane resin paint, and ultra-low-pollution water-based elastic fluororesin paint, which ensures moisture resistance and reduces construction costs.

In addition, the method for constructing the fire-resistant covering structure according to the present invention is a method for constructing the above-mentioned fire-resistant covering structure, in which a sheet-like fire-resistant covering material is manufactured by applying an organic coating material to 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 the wall, thereby achieving the effect of easily constructing a composite fire-resistant structure of columns and beams that suppresses the occurrence of condensation.

In addition, according to another method of construction of a fire-resistant coating structure according to the present invention, a sheet-shaped fire-resistant coating material is manufactured by spraying an organic coating material onto the outside of the sheet-shaped inorganic fire-resistant coating material, which has the effect of easily realizing the formation of a seamless moisture barrier layer even on a complex substrate shape.

In addition, according to another method for constructing a fire-resistant covering structure according to the present invention, a sheet-like inorganic fire-resistant covering material is attached from the outside of a steel column or steel beam to the surface of a wall, and then an organic coating material is sprayed onto the outside of the sheet-like inorganic fire-resistant covering material, which has the effect of forming a stable moisture-proof layer without gaps even at the ends of the fire-resistant covering material.

FIG. 1 is a cross-sectional view showing an embodiment of a fire-resistant covering structure and a construction method thereof according to the present invention. FIG. 2 is a table comparing the measured values of each coating material with the moisture permeability resistivity of in-situ foamed urethane. FIG. 3 is a cross-sectional view showing an example of a conventional composite fire-resistant structure.

Below, an embodiment of the fire-resistant covering structure and its construction method according to the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to this embodiment.

As shown in FIG. 1, a fire-resistant coating 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 coating structure 10 comprises an inorganic fire-resistant coating material 16 that is continuously provided on the surface of the steel beam 14 on the interior space A side and from this surface to the inner surface of the exterior wall 12. A moisture-proof coat 18 (organic coating material) is provided on the outer surface of the fire-resistant coating material 16.

The exterior wall 12 can be made of, for example, a precast reinforced concrete panel, an ALC plate, an extruded cement board (ECP), or the like. The steel beam 14 is made of an H-shaped steel having a web 20 and upper and lower flanges 22, 24. A floor 26 such as a reinforced concrete slab or an ALC plate is provided on the upper surface of the upper flange 22 of the steel beam 14. A layer seal 28 is provided between the floor 26 and the exterior wall 12. A heat insulating material 30 for preventing condensation is provided on the upper side of this layer seal 28 and on the inner surface of the exterior wall 12 below the fire-resistant coating structure 10. The heat insulating material 30 can be made of, for example, a foamed plastic heat insulating material. An interior material 32 is provided on the indoor side at a distance from the heat insulating material 30. A ceiling base material 34 and a ceiling material 36 are provided on the lower side of the lower flange 24 of the steel beam 14.

The fireproof coating material 16 can be made of an inorganic fireproof coating material such as sprayed rock wool, Makibee (registered trademark), or wrapped rock wool felt. In this embodiment, it is assumed that the inorganic fireproof coating material 16 is formed into a sheet shape.

The moisture-proof coat 18 is an organic coating material for suppressing the transmission of water vapor W from the outside to the inside of the fire-resistant coating material 16, and can be composed of materials such as modified asphalt-based waterproofing materials, asphalt-based emulsion moisture-proofing materials, water-soluble acrylic waterproofing materials, ultra-fast curing urethane waterproofing materials, highly elastic acrylic rubber-based wall waterproofing decorative materials, ultra-low-pollution NAD elastic polyurethane resin paints, ultra-low-pollution water-based elastic fluororesin paints, and other materials, or materials that mainly contain these materials. By using such general-purpose waterproofing materials, moisture resistance can be ensured and construction costs can be reduced. However, the moisture-proof coat 18 is not limited to this, and any organic coating material having a moisture permeability resistance higher than that of the fire-resistant coating material 16 can be used. By providing the moisture-proof coat 18 on the outer surface of the fire-resistant 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.

When constructing this fire-resistant coating structure 10, for example, a sheet-like inorganic fire-resistant coating material 16 is prepared, and a moisture-proof coating 18 is applied to the outer surface of this fire-resistant coating material 16 to produce a sheet-like fire-resistant coating material. This sheet-like fire-resistant coating material is then attached from the outside of the steel beams 14 to the surface of the exterior wall 12. In this way, the fire-resistant coating structure 10 that suppresses the occurrence of condensation can be easily constructed. Here, the moisture-proof coating 18 may be applied by spraying onto the outer surface of the fire-resistant coating material 16. In this way, the formation of a seamless moisture-proof layer can be easily achieved even on a complex substrate shape.

Instead of applying the material in this manner, a sheet-like inorganic fireproof coating material 16 may be attached from the outside of the steel beams 14 to the surface of the exterior wall 12, and then the moisture-proof coating 18 may be sprayed onto the surface of the attached fireproof coating material 16. In this way, a stable moisture-proof layer without gaps can be formed even at the ends of the fireproof coating material 16.

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 from the indoor side to pass through, the moisture-proof coating 18 with high moisture permeability resistance is provided on the surface of the fire-resistant coating material 16 to suppress the permeation of water vapor W from the indoor side. 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 in the interior 38 of the composite fire-resistant structure is lowered, and the occurrence of condensation is reduced.

Therefore, according to this embodiment, it is possible to suppress the occurrence of condensation inside 38 of the composite fireproof structure of the steel beam 14. In addition, by applying the moisture-proof coating 18 by a spraying method, it is possible to easily form a seamless moisture-proof layer even on a complex base shape. In addition, it is possible to improve workability.

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-proofing function of the fire-resistant coating material can be guaranteed in an exposed state (without a ceiling). This has the effect of making it highly applicable in rooms where ceilings are not normally installed, such as machine rooms and warehouses.

In the above embodiment, the application to a composite fire-resistant structure of steel beams has been described as an example, but the present invention is not limited to this, and can also be applied to a composite fire-resistant structure of steel columns. In this case, the same effects as those described above can be achieved.

(Example)
Next, an embodiment of the present invention will be described.
As the moisture-proof coating, two types of modified asphalt-based waterproofing materials (waterproofing materials A and B), an asphalt-based emulsion moisture-proofing material, a water-soluble acrylic fire-resistant joint spray (organic waterproofing material), a two-component ultra-fast-curing urethane waterproofing material, and an organic insulating material (on-site foamed urethane) were selected, and the moisture permeability resistance and moisture permeability specific resistance of each material were measured. The measured values of each moisture-proof coating are shown in Figure 2. The modified asphalt-based waterproofing material corresponds to an embodiment of the present invention, and the other materials correspond to comparative examples. Note that for the on-site foamed urethane, no actual measurements were made, and the values listed in Reference 1 were used.

[Reference 1] "Condensation in Buildings - Its Causes and Countermeasures," by Masashi Yamada, Inoue Shoin Publishing, 1996, p. 286

As shown in Figure 2, the moisture permeability resistance of the modified asphalt-based waterproofing material of this embodiment is significantly higher than that of moisture-proof coatings such as urethane foamed in place. Therefore, by applying the moisture-proof coating of this embodiment to the surface of the inorganic fire-resistant coating material that constitutes the composite fire-resistant structure, it is possible to suppress and reduce the occurrence of condensation inside the composite fire-resistant structure.
In addition, with other waterproofing materials and highly waterproof paints, by increasing the thickness of the coating film, it is possible to ensure the same moisture-proofing effect as the modified asphalt-based waterproofing material of this embodiment.

As described above, the fire-resistant coating structure according to the present invention is a fire-resistant coating structure that includes an inorganic fire-resistant coating material that is continuously provided from the outside of the steel columns or steel beams that are arranged adjacent to and facing the wall to the surface of the wall, and further includes an organic coating material that is provided on the outside of the inorganic fire-resistant coating material to suppress the transmission of water vapor from the outside to the inside of the inorganic fire-resistant coating material and has a moisture permeability resistance higher than that of the inorganic fire-resistant coating material, thereby suppressing the occurrence of condensation in the composite fire-resistant structure of the columns and beams.

In addition, according to another fire-resistant coating structure of the present invention, the organic coating material is composed of a material whose main component is any of the following: modified asphalt-based waterproofing material, asphalt-based emulsion moisture-proofing material, water-soluble acrylic-based waterproofing material, ultra-fast-curing urethane waterproofing material, highly elastic acrylic rubber-based wall waterproofing decorative material, ultra-low-pollution NAD elastic polyurethane resin paint, and ultra-low-pollution water-based elastic fluororesin paint, ensuring moisture-proofing properties while reducing construction costs.

In addition, according to the method for constructing the fire-resistant covering structure of the present invention, a sheet-like fire-resistant covering material is manufactured by applying an organic coating material to 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 the wall, so that a composite fire-resistant structure of columns and beams that suppresses the occurrence of condensation can be easily constructed.

In addition, according to another method of construction of a fire-resistant coating structure according to the present invention, a sheet-shaped fire-resistant coating material is manufactured by spraying an organic coating material onto the outside of a sheet-shaped inorganic fire-resistant coating material, so that a seamless moisture barrier layer can be easily formed even on a complex substrate shape.

In addition, according to another method for constructing a fire-resistant covering structure according to the present invention, a sheet-like inorganic fire-resistant covering material is attached from the outside of the steel column or steel beam to the surface of the wall, and then an organic coating material is sprayed onto the outside of the sheet-like inorganic fire-resistant covering material, so that a stable moisture-proof layer without gaps can be formed even at the ends of the fire-resistant covering material.

As described above, the fire-resistant coating structure and its construction method according to the present invention are useful for fire-resistant coating in composite fire-resistant structures of columns and beams, and are particularly suitable for suppressing the occurrence of condensation inside composite fire-resistant structures.

10 Fireproof coating structure 12 Exterior wall (wall body)
14 Steel beam 16 Fireproof coating material 18 Moisture-proof coating (coating material)
20 Web 22 Upper flange 24 Lower flange 26 Floor 28 Layer sealing 30 Heat insulating material 32 Interior material 34 Ceiling underlayment material 36 Ceiling material 38 Inside A Indoors B Outdoors

Claims (2)

A method for constructing a fire-resistant covering structure comprising: an inorganic fire-resistant covering material provided continuously 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; and an organic coating material provided on the outside of the inorganic fire-resistant covering material in order to suppress water vapor transmission from the outside to the inside of the inorganic fire-resistant covering material, the organic coating material having a moisture permeation resistance higher than that of the inorganic fire-resistant covering material,
A method for constructing a fire-resistant covering structure, comprising the steps of: spraying the organic coating material onto the outside of the sheet - like inorganic fire-resistant covering material to produce a sheet-like 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. The method for constructing a fire-resistant coating structure according to claim 1, characterized in that the organic coating material is composed of a material whose main component is any of the following: modified asphalt-based waterproofing material, asphalt-based emulsion moisture-proofing material, water-soluble acrylic-based waterproofing material, ultra-fast-curing urethane waterproofing material, highly elastic acrylic rubber-based wall waterproofing decorative material, ultra-low-pollution NAD elastic polyurethane resin paint, and ultra-low-pollution water- based elastic fluororesin paint.

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