JP7499031B2 - Fireproof wood - Google Patents

Description

The present invention relates to fire-resistant wood.

Conventionally, fire-resistant wood, as disclosed in Patent Document 1, is known as a wooden member that can be used as a pillar or beam member of a building and has high fire resistance in the event of a fire. In this specification, the state in which a fire is occurring is defined as "fire" and the state in which no fire is occurring is defined as "normal time."

The fireproof wood of Patent Document 1 has a wooden load-bearing part as a core material located at the center of the axis, a fireproof material layer provided over the entire outer surface of the wooden load-bearing part, and a burner wood layer provided on the outside of the fireproof material layer via a spacer (connecting member). A fireproof coating material such as heat-resistant rock wool is used as the fireproof material layer. Also, gypsum board or the like is used as the connecting member. The burner wood layer is the outermost layer of finishing material, and is fixed to the inner connecting member by adhesives or screws, etc., and forms part of the fireproof wood.

JP 2018-145654 A

However, in Patent Document 1, the finishing material is fixed to the connecting member and arranged to surround the core material, but the connecting member is merely arranged in contact with the inner fire-resistant covering material. In other words, because the connecting member is not attached to the fire-resistant covering material on the inside, there is a problem in that the connecting member is easily detached from the fire-resistant covering material, and as a result, the outer finishing material is also easily detached.

In view of the above problems, the present invention aims to provide fire-resistant wood that has excellent fire resistance and improved stable support for finishing materials.

The first aspect of the present invention has a rectangular core material made of wood, a thermal buffer material attached to the corners of the core material, a fireproof material attached to the outer surface side of the core material, and a finishing material supported by the thermal buffer material and covering the fireproof material and the thermal buffer material.

In the first embodiment, fireproofing material is attached to the outer surface of the core wood, increasing the fire resistance of the outer surface. In addition, heat buffering material is provided at the corners of the core wood to buffer the transfer of heat. Normally, the corners of a pillar are at a disadvantage in terms of fire resistance, since they are heated from two sides during a fire, but in the first embodiment, the heat buffering material suppresses the temperature rise at the corners, improving the overall fire resistance of the fireproof wood.

In addition to its function of buffering heat transfer, the thermal buffer also functions as a support for the finishing material. This makes it difficult for the finishing material to come off the core material.

In the second aspect of the fireproof wood of the present invention, in the first aspect, the thermal buffer material is a steel material, an air layer is formed on the inside, and the finishing material is attached to the thermal buffer material with a fastening member whose tip is located in the air layer.

In the fire-resistant wood according to the second aspect, the thermal buffer material is a steel material with a relatively large heat capacity, which can further increase the fire resistance of the fire-resistant wood. In addition, the air layer formed on the inside functions as an insulating layer, further improving the fire resistance of the fire-resistant wood.

In the second embodiment, the tip of the fastening member is located in the air layer of the thermal buffer material and does not reach the core material, so that in the event of a fire, the heat of the fastening member exposed to the flames is not directly transferred from the fastening member to the core material. On the other hand, if the finishing material is attached using a metal fastening member so that the tip of the fastening member reaches the core material, there is a concern that the heat of the fastening member will be directly transferred to the core material, accelerating carbonization and combustion of the core material. In this regard, in the second embodiment, heat is not directly transferred from the fastening member to the core material, reducing the possibility of carbonization and combustion of the core material, and the fire resistance of the fire-resistant wood can be further improved.

In addition, because the tip of the fastening member 22 is located in the air layer, the area where the outer surface of the fastening member comes into contact with the surroundings is reduced compared to when the tip is located at the core material 12. This reduces the frictional force that the fastening member receives from the surroundings when inserting and removing it, making it easier to insert and remove the fastening member and reducing the burden of the work of installing and removing the finishing material.

The fire-resistant wood according to the third aspect of the present invention is the first or second aspect, in which a lath mesh is attached to the outer surface side of the core material as a base material that supports the fire-resistant material, and the fire-resistant material is a foamable fire-resistant coating applied to the lath mesh.

In the fireproof wood according to the third aspect, the fireproof material is a foaming fireproof coating that expands when a certain amount of heat is applied, so that the thickness of the fireproof wood can be kept small under normal conditions when no fire is occurring. This allows the dimensions of the fireproof wood to be designed to be compact while increasing the fire resistance of the fireproof wood. In addition, because the base material for the fireproof coating is a lath net, the fireproof coating is entangled in the mesh of the lath net and is firmly supported. Therefore, according to the third aspect, even if the fireproof coating expands and increases in volume, the expanded fireproof coating can be prevented from falling off the base material.

The fire-resistant wood of the present invention provides fire-resistant wood that has excellent fire resistance and provides improved stable support for finishing materials.

FIG. 2 is a perspective view illustrating the configuration of the fire-resistant wood according to the present embodiment with a portion of the finishing material cut away. 1 is a cross-sectional view of a fire-resistant wood according to an embodiment of the present invention, taken perpendicular to an axial direction (the vertical direction in FIG. 1 ) and viewed from above. FIG. 2 is a cross-sectional view illustrating a state in which a fireproof coating, which is a fireproof material, is expanded in the fireproof wood according to the embodiment. FIG. 2 is a cross-sectional view of a fire-resistant wood according to a comparative example. FIG. 2 is a cross-sectional view of a fire-resistant wood according to a first modified example of the present embodiment. FIG. 11 is a cross-sectional view illustrating a state in which a fireproof coating, which is a fireproof material, of the fireproof wood according to the first modified example is expanded. 1A is a partial cross-sectional view of a fire-resistant wood according to a second modified example, and FIG. 1B is a partial cross-sectional view of a fire-resistant wood according to a third modified example. 13A is a partial cross-sectional view of a fire-resistant wood according to a fourth modified example, and FIG. 13B is a partial cross-sectional view of a fire-resistant wood according to a fifth modified example. FIG. 13 is a cross-sectional view of a fire-resistant wood according to a sixth modified example, cut perpendicularly to the axial direction and viewed from above.

The following describes an embodiment of the present invention. In the following description of the drawings, identical or similar parts are given the same or similar symbols. However, the relationship between thickness and planar dimensions in the drawings, and the ratio of thickness of each device and each component, etc., differ from the actual ones. Therefore, specific thicknesses and dimensions should be determined with reference to the following description. In addition, there are parts in which the dimensional relationships and ratios differ between the drawings.

<Fire-resistant wood structure>
1, the fire-resistant wood 10 according to this embodiment has a rectangular columnar core material 12 made of wood, a plurality of heat buffer materials 14A attached so as to cover the corners of the core material 12, and a fire-resistant material 18A attached to the outer surface side of the core material 12. The fire-resistant wood 10 also has a finishing material 20 supported by the heat buffer materials 14A and covering the fire-resistant materials 18A and the heat buffer materials 14A.

The core material 12 has a square prism shape, and the tree species may be, for example, cedar, cypress, or the like. In the present invention, the shape of the core material is not limited to a square prism shape, and may be another polygonal prism shape, such as an octagonal prism. The shape of the core material may be a square prism with chamfered corners. The core material is not limited to a single material, and may be a laminated material.

As shown in FIG. 2, the thermal buffer material 14A is a square steel pipe with a rectangular outer edge in cross section, and is attached to each of the four corners of the core material 12 so as to cover the corners of two adjacent faces. Specifically, one square steel pipe is placed on each of the two adjacent faces of the corners, so that the corners are in approximate linear contact with each other.

The length of the thermal buffer 14A in the longitudinal direction (the vertical direction in FIG. 1) is the same as the length of the core material 12 in the longitudinal direction, and the thermal buffer 14A buffers the heat applied to the core material 12 in the event of a fire. The thermal buffer 14A and the core material 12 are integrated together, for example, by adhesive or drift pins. An air layer is formed inside the steel pipe of the thermal buffer 14A, and the formed air layer functions as an insulating layer in the event of a fire.

The fire-resistant material 18A is, for example, a foaming fire-resistant coating that expands when heat is applied and exceeds a certain temperature. The thickness of the fire-resistant coating can expand to more than five times its normal thickness in the event of a fire. A lath mesh 16 is attached to the outer surface of the core material 12 as a base material that supports the fire-resistant material 18A.

The lath net 16 is attached to the pair of thermal buffer materials 14A, 14A, which are attached to the corners at both ends of one side of the core material 12 in FIG. 2, by spanning between them. Similarly, the lath net 16 is attached to the other sides of the core material 12 by spanning between the pair of thermal buffer materials 14A, 14A at both ends. The arrangement pattern of the lath net 16 is not limited to the one illustrated in FIG. 2, which spans between the pair of thermal buffer materials 14A, 14A, and may be arranged on the thermal buffer material 14A so that the entire outer surface of the thermal buffer material 14A is covered. The fireproof material 18A is applied continuously with a constant thickness on the lath net 16 and on the outer surface of the thermal buffer material 14A. The fireproof material 18A can be applied, for example, by spraying fireproof paint using a spraying device such as a sprayer, or by brushing.

Here, for example, instead of using a fire-resistant coating, a method is known in which a fire-resistant coating is applied around the core material 12 to improve the fire resistance of wood. However, in order to ensure the fire resistance of flammable wood for a certain period of time, it is often necessary to apply a relatively thick fire-resistant coating, for example 60 mm or more. This poses the problem of laborious application work and high costs. Other methods are known, such as installing a fire-retardant layer around the core material 12 and combining wood materials with steel members to create so-called hybrid-type fire-resistant wood, but these have problems in that they require labor and time for quality control in addition to costs.

In this respect, in this embodiment, the entire outer surface of the core material 12 can be sprayed with fireproof paint in one go using a spray device, reducing the workload involved in fireproofing. In this embodiment, the fireproof material 18A of the fireproof paint is applied relatively thickly, at a thickness of about 5 mm or more, to achieve fire resistance equivalent to that of a fireproof coating without using a fireproof coating.

The lath net 16 may be formed, for example, by bending and intertwining iron or steel wires, or by combining reinforcing bars so that they cross each other. A lath net in which a mesh pattern is formed by punching an iron or steel plate may also be used. The mesh pattern may be in any suitable shape, such as a rectangular or circular shape, other than the diamond shape exemplified in FIG. 1. The lath net 16 may be formed by arranging linear members such as iron wires, steel wires, or reinforcing bars at right angles to each other so that the overall shape is a lattice when viewed from the front.

In the present invention, materials other than metal may be used for the lath net. Also, multiple linear members may be arranged in parallel along one direction without intersecting. However, when linear members intersect, as in the lath net 16 illustrated in FIG. 1, the shape of the intersection is not flat, and certain irregularities are formed at the intersection. At the intersection of the irregularities, the fireproof coating film is more likely to become entangled with the linear members, so the fireproof material 18A can be held more firmly.

The finishing material 20 can be made from wood (general wood) that is commonly used in wooden buildings, such as cedar or cypress. The finishing material 20 is attached to and supported by the thermal buffer material 14A using metal fastening members 22, such as screws or nails, that have a relatively high thermal conductivity. Note that pilot holes for inserting the fastening members 22 can be pre-drilled in the thermal buffer material 14A.

As shown in FIG. 2, the fastening member 22 is inserted from the outside, and the tip is located in the air space inside the steel pipe, which is the thermal buffer material 14A, and does not reach the inside of the core material 12. Note that the method of attaching the finishing material 20 to the thermal buffer material 14A is not limited to the fastening member 22, and other means, such as adhesive, may be used.

In addition, in the present invention, materials other than general wood can be appropriately used as the finishing material. In particular, a layer that can exert a fire-retarding effect (fire-retarding layer) can be suitably used as the finishing material for the purpose of increasing fire resistance. Fire-retarding layers include layers having flame retardancy and layers that can suppress thermal conduction. Specifically, for example, a layer having flame retardancy can be used as a layer that is injected with a flame retardant to make wood fireproof. In addition, the layer that can suppress thermal conduction can be formed from a material that has a larger heat capacity than general wood, a material that has higher insulation properties than general wood, or a material that has higher thermal inertia than general wood, or it can be formed by combining these materials with general wood.

Materials with a higher heat capacity than ordinary wood include, for example, mortar, stone, glass, fiber-reinforced cement, inorganic materials such as gypsum, and various metal materials. Materials with higher thermal insulation than ordinary wood include, for example, calcium silicate board, gypsum board, rock wool, and glass wool. Materials with a higher thermal inertia than ordinary wood include, for example, celanbu, jarrah, and bongosi. By increasing the fire resistance of the finishing material 20 in this way, the fire resistance of the fire-resistant wood 10 can be further strengthened.

The fire-resistant wood 10 according to this embodiment can be used as various components in a fire-resistant building, such as pillars, beams, floors, and walls. As shown in FIG. 3, when a fire breaks out, even if the finishing material 20 located on the outside of the fire-resistant wood 10 disappears, the fire-resistant material 18A1 expands due to heat for a certain period of time. The expanded 18A1 covers the entire outer surface of the fire-resistant wood 10, protecting the core material 12 and the thermal buffer material 14A from the flames.

(Action and Effect)
In the fire-resistant lumber 10 according to this embodiment, the fire-resistant material 18A is attached to the outer surface of the core material 12, thereby enhancing the fire resistance of the outer surface. In addition, the corners of the core material 12 are provided with heat buffer materials 14A that cover the corners and buffer the transfer of heat. Normally, the corners of a pillar are at a disadvantage in terms of fire resistance because they are heated from two sides during a fire, but in this embodiment, the heat buffer materials 14A suppress the temperature rise at the corners, thereby improving the fire resistance of the fire-resistant lumber 10 overall.

In addition to its function of buffering heat transfer, the thermal buffer material 14A also functions as a support material for supporting the finishing material 20. In this embodiment, the thermal buffer material 14A is attached to both the core material 12 and the finishing material 20, so the finishing material 20 is less likely to come off the core material 12 compared to a configuration in which the support material is simply supported by abutting against an inner member.

Therefore, according to the fire-resistant wood 10 of this embodiment, it is possible to provide fire-resistant wood 10 that has excellent fire resistance and has an improved stable support for the finishing material 20. In addition, since the thermal buffer material 14A is a member that also supports the finishing material 20, a support material other than the thermal buffer material 14A is not required, and it is possible to reduce the number of members that make up the fire-resistant wood 10.

In addition, according to this embodiment, the thermal buffer material 14A is a steel material with a relatively large heat capacity, which can further increase the fire resistance of the fire-resistant wood 10. In addition, the air layer formed on the inside functions as an insulating layer, further improving the fire resistance of the fire-resistant wood 10.

In addition, since the tip of the metal fastening member 22 is located in the air layer of the thermal buffer material 14A and does not reach the core material 12, in the event of a fire, the heat of the fastening member 22 exposed to the flames is not directly transferred from the fastening member 22 to the core material 12. On the other hand, as shown in FIG. 4, in the case of the fire-resistant wood 10Z according to the comparative example, the finishing material 20 is attached by the metal fastening member 22 so that the tip of the fastening member 22 reaches the core material 12.

In the comparative example, there is a concern that the heat of the fastening member 22 is directly transferred to the core material 12, accelerating the carbonization or combustion of the core material 12. In this regard, in the present embodiment, as shown in FIG. 3, the presence of the thermal buffer material 14A prevents the heat from being directly transferred from the fastening member 22 to the core material 12, reducing the possibility of the core material 12 carbonizing or burning, and further improving the fire resistance of the fire-resistant lumber 10. In addition, the core material 12 may become vulnerable to heat if it is damaged or scratched by the tip of the fastening member 22, but this embodiment prevents the core material 12 from being damaged or scratched.

In addition, because the tip of the fastening member 22 is located in the air layer, the area of contact of the outer surface of the fastening member 22 with the surroundings is reduced compared to when the tip is located at the core material 12. This reduces the frictional force that the fastening member 22 receives from the surroundings when inserting and removing it, making it easier to insert and remove the fastening member 22 and reducing the burden of the work of attaching and removing the finishing material 20. Therefore, according to this embodiment, combined with not damaging the core material 12, the finishing material 20 can be easily replaced during renovations, etc.

In addition, in this embodiment, the fire-resistant material 18A is a foaming fire-resistant coating that expands when a certain amount of heat is applied, so the thickness of the fire-resistant wood 10 can be kept small during normal times when no fire is occurring. This allows the dimensions of the fire-resistant wood 10 to be designed compactly while increasing the fire resistance of the fire-resistant wood 10.

In addition, since the base material for the fire-resistant coating is the uneven lath mesh 16, the fire-resistant coating is entangled in the mesh of the lath mesh 16 and is firmly supported. Therefore, according to this embodiment, even if the fire-resistant coating expands and increases in volume, the expanded fire-resistant coating can be prevented from falling off the base material. In addition, the lath mesh 16 makes it possible to apply a relatively thick coating of the fire-resistant material 18A to the outer surface side of the core material 12. Therefore, the necessary fire resistance can be achieved with just the fire-resistant material 18A of the fire-resistant coating, and it is possible to reduce the effort required for applying fire-resistant treatment other than the fire-resistant material 18A, such as fire-resistant coating.

In addition, in this embodiment, a steel pipe is used as the thermal buffer material 14A, and steel materials including steel pipes have a large heat capacity, but also a relatively high thermal conductivity. However, because the fire-resistant material 18A is coated all over the outer surface of the thermal buffer material 14A of the steel pipe, the transfer of heat from the thermal buffer material 14A to the core material 12 can be suppressed in the event of a fire.

<First Modification>
Next, fire-resistant lumber 10A to 10E according to the first to fifth modified examples of the present embodiment will be described. In the following description of the fire-resistant lumber 10A to 10E according to the modified examples, differences from the fire-resistant lumber 10 shown in Figures 1 to 3 will be mainly described, and duplicate descriptions of equivalent members with the same names will be omitted.

In the fire-resistant wood 10 shown in Figures 1 to 3, the fire-resistant material 18A is provided continuously on the lath mesh 16 and on the outer surface of the thermal buffer material 14A, but as shown in Figure 5, the fire-resistant material 18B does not have to be provided on the outer surface of the thermal buffer material 14A. In the fire-resistant wood 10A according to the first modified example shown in Figure 5, the fire-resistant material 18B is provided only on the lath mesh 16, and is not provided on the outer surface of the thermal buffer material 14A except in the area near the lath mesh 16.

In the case of the fire-resistant wood 10A according to the first modification, the fire-resistant material 18B provided on the lath mesh 16 also expands in the event of a fire. As shown in FIG. 6, the fire-resistant material 18B1 expands outward from each of the four sides of the core material 12. At the corners of both ends of each side of the core material 12, the fire-resistant material 18B1 expanding from adjacent sides joins together and covers the outer surface of the thermal buffer material 14A. In other words, in the first modification, the thickness of the coating of the fire-resistant material 18B under normal conditions is set so that the fire-resistant material 18B1 expanding in the event of a fire joins together at the corners of the adjacent sides, preventing the outer surface of the thermal buffer material 14A from being exposed.

According to the first modified example, under normal circumstances, the fire-resistant material 18B is not provided on the portion of the outer surface of the heat buffer material 14A that faces the finishing material 20, and the outer surface of the heat buffer material 14A is exposed, so pilot holes for inserting the fastening members 22 can be easily drilled. Also, compared to the fire-resistant wood 10 shown in Figures 1 to 3, it is possible to reduce the amount of fire-resistant material 18B used within the range in which the necessary fire resistance of the fire-resistant wood 10A can be achieved.

In FIG. 5, the fireproof material 18B is not applied to the opposing outer surfaces of the two adjacent thermal buffer materials 14A at the corner. However, by partially applying the fireproof material 18B to the opposing outer surfaces, the resistance to heat from the finishing material 20 side toward the center of the core material 12 at the corner may be further increased.

The fire resistance may be improved by filling (packing) the hollow inside the steel pipe of the thermal buffer material 14A with a fire-resistant material such as rock wool. The fire-resistant material may be other than rock wool. For example, the fire-resistant material may be formed by pouring mortar or gypsum into the hollow after the fastening member 22 is inserted. In this way, the fire-resistant material is filled in the hollow of the thermal buffer material 14A to increase the fire resistance of the corners, thereby reducing the amount of fire-resistant material 18B used while further reinforcing the fire resistance of the fire-resistant wood 10A. Note that the configuration in which the fire-resistant material is filled in the hollow of the thermal buffer material is not limited to the case of the fire-resistant wood 10A according to the first modified example, and can be applied to all fire-resistant wood according to the present invention, such as the fire-resistant wood 10 shown in FIG. 1.

<Second Modification>
In the fire-resistant wood 10 shown in Figures 1 to 3, the thermal buffer material 14A is a square steel pipe. However, as shown in Figure 7(A), a steel channel material with a C-shaped cross section may be provided adjacent to the corner of the core material 12 as the thermal buffer material 14B, and an air layer may be formed between the thermal buffer material 14B and the core material 12 on the inside. As in the case of the fire-resistant wood 10B according to the second modified example shown in Figure 7(A), any bent or curved steel material that can form an air layer on the inside can be used as the thermal buffer material in the present invention, even if it is not a square steel pipe.

<Third Modification>
Moreover, it is not essential that two thermal buffer materials are disposed for each corner of the core material 12, and as shown in Fig. 7(B), one thermal buffer material 14C may be disposed for each corner of the core material 12. In the fire-resistant wood 10C according to the third modified example shown in Fig. 7(B), the thermal buffer material 14C is also a channel material, and an air layer is formed between the thermal buffer material 14C and the core material 12 on the inside. In the case of the third modified example, the thermal buffer material 14C is disposed so that the corner of the core material 12 is located on the inside of the C-shape of the thermal buffer material 14C, thereby mitigating two-sided heating of the corner and making it possible to reduce the amount of the thermal buffer material 14C used within a range that allows the required fire resistance to be achieved.

<Fourth Modification>
In the case of the fire-resistant wood 10D according to the fourth modification shown in FIG. 8(A), the channel material as the thermal buffer material 14D has three outer surfaces forming a C-shape, and one of the three outer surfaces is joined to the outer surface of the core material 12. The present invention is valid even if a closed air layer is not formed inside the thermal buffer material 14D, in other words, an open air layer is formed, as in the fire-resistant wood 10D according to the fourth modification. In addition, according to the fourth modification, the thermal buffer material 14D is joined to the core material 12 using an outer surface wider than the end surface. Therefore, the unity between the thermal buffer material 14D and the core material 12 can be improved compared to the case where the end surfaces of the thermal buffer materials 14B and 14C are joined to the outer surface of the core material 12 as shown in FIG. 7.

In FIG. 8(A), a case is illustrated in which fire-resistant material 18A is applied to the outer surface of heat buffer material 14D facing finishing material 20, and finishing material 20 is supported by heat buffer material 14D via the applied fire-resistant material 18A. However, the present invention is not limited to this. For example, fire-resistant material 18A may not be applied to the outer surface of heat buffer material 14D facing finishing material 20, and finishing material 20 may be directly supported by heat buffer material 14D. In other words, as long as the required fire resistance is achieved, fire-resistant material 18A may be partially omitted.

<Fifth Modification>
Also, as shown in Fig. 8(B), the thermal buffer material 14E may be an angle material (equal leg angle steel) having an L-shaped cross section. In the case of the fire-resistant wood 10E according to the fifth modified example shown in Fig. 8(B), the thermal buffer material 14E has two outer surfaces forming an L shape, and one of the two outer surfaces is joined to the outer surface of the core material 12. In addition, an auxiliary support member 26 is attached to the portion where the other outer surface of the thermal buffer material 14E is located via a fixing device 28 such as a screw or a nail.

The auxiliary support member 26 has an L-shaped cross section and connects the thermal buffer material 14E and the finishing material 20. Like the thermal buffer material 14E, the auxiliary support member 26 has two L-shaped outer surfaces, one of which is joined to the inner surface of the thermal buffer material 14E. The other outer surface of the auxiliary support member 26 is joined to the inner surface of the finishing material 20. The auxiliary support member 26 is attached to the finishing material 20 by a fastening member 22.

The longitudinal length of the auxiliary support member 26 may be the same as that of the thermal buffer material 14E, or may be shorter than that of the thermal buffer material 14E, so long as it can support the finishing material 20. In addition, while FIG. 8(B) illustrates a fastener 28 with a pointed tip, such as a screw or nail, the present invention is not limited to this. The fastener may be, for example, a bolt and nut, as long as it can fasten the thermal buffer material 14E and the auxiliary support member 26 together. Alternatively, the thermal buffer material 14E and the auxiliary support member 26 may be joined with an adhesive.

<Sixth Modification>
1 to 8, the fire-resistant materials 18A and 18B of the fire-resistant lumber 10, 10A to 10E are each formed of a single layer, but the present invention is not limited to this, and the fire-resistant material may have two or more layers. For example, as shown in Fig. 9, a fire-resistant lumber 10F according to a sixth modified example has a two-layer fire-resistant material 18C consisting of an inner layer 18C1 and an outer layer 18C2.

The inner layer 18C1 of the fire-resistant material 18C is, for example, gypsum board, and is arranged in the central region of the outer surface (periphery) of the core material 12, excluding the corners where the thermal buffer material 14A is arranged. That is, in the fire-resistant lumber 10F, the inner layers 18C1 of the four gypsum boards are attached to the parts of the four outer surfaces of the core material 12 where the thermal buffer material 14A is not arranged. The inner layers 18C1 are fixed directly to the core material 12 by fixing members (not shown) such as screws, or indirectly via rafters, etc.

The inner layer 18C1 is a layer that enhances heat insulation and has fire resistance. In the present invention, the inner layer is not limited to gypsum board, and other materials can be used as appropriate. For example, calcium silicate board, precast concrete board, ALC board, water glass impregnated cork, wrapped rock wool mat, water glass impregnated rock wool mat, sprayed rock wool, etc. can be used as the inner layer. In other words, it is preferable that the inner layer is a material that is normally solid and retains moisture in an air-dry state.

In the sixth modified example, a pair of thermal buffer materials 14A, 14A are attached to the corners of both ends of one side of the core material 12, as in the case of the fireproof material 18A of the fireproof wood 10 illustrated in FIG. 2, and a lath net 16 is placed between the pair of thermal buffer materials 14A, 14A. However, as shown in FIG. 9, in the fireproof material 18C of the sixth modified example, an inner layer 18C1 is provided, so the lath net 16 is attached on the outer surface of the thermal buffer material 14A, further outboard than in the case of the fireproof material 18A of the fireproof wood 10 illustrated in FIG. 2.

The outer layer 18C2 of the fire-resistant material 18C is a foaming fire-resistant paint that is applied continuously with a constant thickness, similar to the case of the fire-resistant material 18A of the fire-resistant wood 10 illustrated in FIG. 2. The outer layer 18C2 can be similarly applied to the outer peripheral surface of the inner layer 18C1 and the thermal buffer material 14A by spraying using a spraying device such as a sprayer or by brushing. The outer layer 18C2 is formed of a material that can have air bubbles at least at a predetermined temperature or higher.

The "predetermined temperature" is the temperature at which the moisture held in the inner layer 18C1 evaporates due to flame or heat, specifically, a temperature of 100 degrees Celsius. In the sixth variant, when the outer layer 18C2 is heated to a temperature equal to or higher than the predetermined temperature in the event of a fire, the outer layer 18C2 foams and forms bubbles, increasing the volume of the outer layer 18C2. Then, as shown in FIG. 3, the outer layer 18C2 expands, achieving fire resistance.

In the sixth variant, a gypsum board that further enhances heat insulation is provided as an inner layer 18C1 inside the outer layer 18C2 of fire-resistant paint. Therefore, compared to a case where the fire-resistant material is composed of only one layer of fire-resistant paint, it is possible to effectively achieve both enhanced heat insulation and improved fire resistance.

<Other embodiments>
Although the present invention has been described by the above disclosed embodiment, this description does not limit the present invention. It should be considered that various alternative embodiments, examples and operating techniques will become apparent to those skilled in the art from the present disclosure.

For example, in this embodiment, the thermal buffer materials 14A to 14E are all steel materials, but the present invention is not limited to this, and materials other than steel materials, such as concrete, ceramic, wood, gypsum, gypsum board, calcium silicate board, etc., may be used as the thermal buffer material. As other materials, various materials that can be used as fire-retardant layers, as mentioned in the description of the finishing material 20, can be used.

In addition, in this embodiment, a foamable fireproof coating supported by the lath net 16 is exemplified as the fireproof material 18A, but the present invention is not limited to this combination, and for example, the fireproof paint may be directly applied to the outer surface of the core material 12. In addition, the fireproof material 18A does not need to be a fireproof paint, and materials other than fireproof paint, such as a fireproof coating, may be used.

The present invention can also be constructed by combining the components of each of the fire-resistant woods 10, 10A-10F shown in Figures 1-9. The present invention includes various embodiments not described above, and the technical scope of the present invention is determined only by the invention-specific matters in the claims that are appropriate from the above explanation.

10, 10A to 10F Fireproof wood 12 Core material 14A to 14E Heat buffer material 16 Lath net 18A, 18A1 Fireproof material 18B, 18B1 Fireproof material 18C Fireproof material 20 Finishing material 22 Fastening member

Claims (3)

A prismatic core material made of wood material;
A thermal buffer material attached to a corner of the core material;
A fireproof material attached to the outer surface side of the core material;
a finishing material supported by the thermal buffer material and covering the fireproof material and the thermal buffer material;
Fire-resistant wood having The thermal buffer material is a steel material, and an air layer is formed inside the steel material.
The fire-resistant wood of claim 1 , wherein the finishing material is attached to the thermal buffer material with a fastening member whose tip is located in the air space. A lath mesh is attached to the outer surface of the core material as a base material for supporting the fireproof material,
The fireproof wood according to claim 1 or 2, wherein the fireproof material is a foamable fireproof coating applied to the lath net.