Wood-based refractory structures

Abstract

To provide a fire-resistant wooden structure that ensures fire resistance and offers excellent workability. [Solution] A fire-resistant wooden structure 1 used as a column or beam in a building comprises a wooden structural core 10 that supports the load, a first covering material 11 that covers the outer surface of the wooden structural core 10, and a second covering material 12 that covers the outer surface of the first covering material 11. The first covering material 11 contains organic fibers and has a water content of 6.0% or more derived from free water or crystal water, while the second covering material 12 has a water content of 3.0% or less derived from free water or crystal water. Furthermore, the first covering material 11 is made of either slag gypsum board or wood wool cement board, and the second covering material 12 is made of calcium silicate board.

Description

[Technical Field]

[0001] This invention relates to a wood-based fire-resistant structure. [Background technology]

[0002] Conventionally, fire-resistant structures have been known that, even if the surface is carbonized by exposure to flames during a fire, prevent the core material from carbonizing, thereby allowing it to maintain load over a long period of time. One example of a fire-resistant structure is a wood-based fire-resistant structure in which a non-combustible material is attached to the outer surface of a wood-based structural core material.

[0003] For example, Patent Document 1 discloses a wooden building member having a long, rectangular structural part that receives a load, a covering part that covers all four sides of the cross-section of the structural part along its entire length, and a gypsum board interposed in a layer between the structural part and the covering part to prevent the load acting on the structural part from being transmitted to the covering part. Since the structural part is covered with gypsum board, it is not directly exposed to flames and carbonization proceeds very slowly, thus improving fire resistance. In addition, since the surface of the wooden building member is covered with the covering part, the gypsum board is not exposed to the outside, thus ensuring its appearance. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Patent No. 4359275 [Overview of the project] [Problems that the invention aims to solve]

[0005] Incidentally, in the wooden building components described in Patent Document 1, gypsum board is used as the non-combustible material. However, gypsum board has the disadvantage of being heavy and difficult to work with as a covering material. Therefore, it is not desirable to use gypsum board alone as a covering material to ensure fire resistance.

[0006] Therefore, the present invention aims to provide a wood-based fire-resistant structure that ensures fire resistance and has excellent workability. [Means for solving the problem]

[0007] To address the above issues, the present invention provides a fire-resistant wooden structure for use in columns, beams, or walls of a building, comprising: a wooden structural core material that supports a load; a first covering material that covers the outer surface of the wooden structural core material; and a second covering material that covers the outer surface of the first covering material, wherein the first covering material contains organic fibers, free water, or crystalline water, and the proportion of water derived from free water or crystalline water is 6.0% or more, and the proportion of water derived from free water or crystalline water in the second covering material is 3.0% or less.

[0008] Here, the bulk density of the second coating material is 0.15 g / cm³. 3 More than 0.70g / cm 3 It is preferable that it be less than [a certain value].

[0009] Furthermore, the fire-resistant wooden structure of the present invention is a fire-resistant wooden structure used for columns, beams, or walls of a building, comprising: a wooden structural core material that supports a load; a first covering material that covers the outer surface of the wooden structural core material; and a second covering material that covers the outer surface of the first covering material, wherein the first covering material is made of slag gypsum board and the second covering material is made of calcium silicate board.

[0010] Furthermore, it is desirable that the thickness of the first covering material be 10 mm or more and 30 mm or less, and the thickness of the second covering material be 10 mm or more and 30 mm or less.

[0011] Furthermore, the fire-resistant wooden structure of the present invention is a fire-resistant wooden structure used for columns, beams, or walls of a building, comprising: a wooden structural core material that supports a load; a first covering material that covers the outer surface of the wooden structural core material; and a second covering material that covers the outer surface of the first covering material, wherein the first covering material is made of wood wool cement board, and the second covering material is made of calcium silicate board.

[0012] Furthermore, it is desirable that the thickness of the first covering material be 10 mm or more and 20 mm or less, and the thickness of the second covering material be 20 mm or more and 30 mm or less.

[0013] Here, it is desirable that the second covering material further comprises a surface material covering the outer circumferential surface, the surface material being fixed to the first covering material and the second covering material by a fixing member, and the tip of the fixing member being positioned inside the first covering material so as not to penetrate the first covering material.

[0014] Furthermore, it is desirable that the second covering material is further provided with a surface material covering its outer circumferential surface, and that the surface material is fixed to the wood structural core material by a fixing member that penetrates the first covering material and the second covering material.

[0015] Furthermore, it is desirable that the thickness of the first coating material be three times or less the thickness of the second coating material. Alternatively, it is desirable that the thickness of the second coating material be three times or less the thickness of the first coating material. Alternatively, it is desirable that the first coating material has the same thickness as the second coating material. [Effects of the Invention]

[0016] Thus, in the wooden fire-resistant structure of the present invention, the first covering material that covers the outer peripheral surface of the core material for the wooden structure contains organic fibers and has a moisture ratio derived from free water or crystal water of 6.0% or more, and the second covering material that covers the outer peripheral surface of the first covering material has a moisture ratio derived from free water or crystal water of 3.0% or less. Further, in the wooden fire-resistant structure of the present invention, the first covering material that covers the outer peripheral surface of the core material for the wooden structure is composed of a slag gypsum board or a wood wool cement board, and the second covering material is composed of a calcium silicate board.

[0017] Thereby, the periphery of the core material for the wooden structure is covered with the first covering material and the second covering material having high fire resistance so as to form a layer structure. Therefore, it is possible to improve the fire resistance of the wooden fire-resistant structure and ensure excellent workability.

[0018] Here, the bulk density of the second covering material is 0.15 g / cm 3 or more and less than 0.70 g / cm 3 Thereby, by using the second covering material having a bulk density smaller and lighter than that of the reinforced gypsum board, the workability can be further improved.

[0019] Further, the wooden fire-resistant structure further includes a surface material that covers the outer peripheral surface of the second covering material, and the surface material is fixed to the first covering material and the second covering material by fixing members, and the tips of the fixing members are arranged inside the first covering material so as not to penetrate the first covering material. Thereby, it is possible to prevent the fixing members from becoming heat bridges that carbonize the core material for the wooden structure during a fire. Therefore, it is possible to further improve the fire resistance of the wooden fire-resistant structure.

[0020] Further, the surface material is fixed to the core material for the wooden structure by fixing members that penetrate the first covering material and the second covering material. Thereby, the fixing members can integrate the surface material, the first covering material, the second covering material, and the core material for the wooden structure more firmly.

[0021] Furthermore, the thickness of the first covering material is three times or less the thickness of the second covering material, or the thickness of the second covering material is three times or less the thickness of the first covering material, or the first covering material has the same thickness as the second covering material. In any of these cases, the core material for the wood structure can be covered with a highly fire-resistant material to form a layered structure. Therefore, in any of these cases, the fire resistance of the wood fire-resistant structure can be further improved.

[0022] Furthermore, when the first covering material is slag gypsum board and the second covering material is calcium silicate board, the thickness of the first covering material is 10 mm to 30 mm, and the thickness of the second covering material is 10 mm to 30 mm. Also, when the first covering material is wood wool cement board and the second covering material is calcium silicate board, the thickness of the first covering material is 10 mm to 20 mm, and the thickness of the second covering material is 20 mm to 30 mm. In other words, by using a non-combustible first covering material and a lightweight calcium silicate board in combination within the above thickness ranges, both fire resistance and excellent workability can be ensured. [Brief explanation of the drawing]

[0023] [Figure 1] This is a partial perspective view showing the interior of a wood fire-resistant structure according to an embodiment of the present invention. [Figure 2] This is a cross-sectional view of a wood fire-resistant structure according to an embodiment of the present invention. [Figure 3] (a) is a schematic enlarged cross-sectional view of the wood fire-resistant structure before heating, and (b) is a schematic enlarged cross-sectional view of the wood fire-resistant structure in the first stage during heating. [Figure 4] (a) is a schematic enlarged cross-sectional view of the wood fire-resistant structure during the second stage of heating, and (b) is a schematic enlarged cross-sectional view of the wood fire-resistant structure during the third stage of heating. [Figure 5] This graph shows the relationship between temperature changes and thermal conductivity for each material. [Figure 6] This graph shows the relationship between temperature changes and linear shrinkage rates for each material. [Figure 7]This graph shows the relationship between the temperature change of each material and its apparent volumetric specific heat. [Figure 8] This figure shows the relationship between the temperature rise of each material and the amount of heat required to achieve that temperature rise. [Figure 9] This is a diagram illustrating the outline of the test specimen used in fire resistance experiments. [Figure 10] This graph shows the temperature change inside the heating furnace during a refractory test. [Figure 11] This graph shows the temperature changes at each measurement point on the test specimen during a fire resistance test. [Modes for carrying out the invention]

[0024] Embodiments of the present invention will now be described with reference to the drawings. Figure 1 is a perspective view of a fire-resistant wooden structure according to an embodiment of the present invention, and Figure 2 is a cross-sectional view thereof.

[0025] As shown in Figure 1, the fire-resistant wooden structure 1 is a structure used for columns, beams, or walls of a building, and comprises a wooden structural core material 10 that supports the load, a first covering material 11 that covers the outer surface of the wooden structural core material 10, a second covering material 12 that covers the outer surface of the first covering material 11, and a surface material 13 that covers the outer surface of the second covering material 12.

[0026] <Core material for wood-based structures> The core material 10 for the wood structure is formed in the shape of a rectangular prism with four sides. The core material 10 for the wood structure is not limited to the type of tree, and can be made from wood such as cedar, cypress, Japanese red pine, Japanese black pine, Japanese cypress, Japanese larch, Western red cypress, Western red cypress, Western hemlock, Japanese zelkova, chestnut, oak, or beech. The core material 10 for the wood structure can be solid wood, laminated wood, veneer laminated wood, orthogonal laminated wood, or ungraded wood. The core material 10 for the wood structure can be made from commonly available materials or custom-made materials.

[0027] The core material 10 for wood structures has no density limit, but for example, a density of 0.38 ± 0.08 g / cm³ is acceptable. 3It can be as described above. The core material 10 for the wooden structure contains moisture, and there is no limit on the ratio of moisture. For example, the moisture content can be 15% or less. As shown in FIGS. 1 and 2, the core material 10 for the wooden structure can be a square bar with a rectangular cross-section (for example, 600 mm × 600 mm).

[0028] <First coating material> The first coating material 11 is formed in a cylindrical shape in cross-section so as to surround the four side surfaces of the core material 10 for the wooden structure. As shown in FIG. 2, the first coating material 11 is composed of a plurality of plate-like members, and each plate-like member is fixed to each side surface of the core material 10 for the wooden structure by a first fixture 21 such as a screw. The first fixture 21 penetrates the first coating material 11 in the thickness direction, and the tip is inserted into the core material 10 for the wooden structure. The first coating material 11 is formed of, for example, a slag gypsum board or a wood wool cement board.

[0029] <Slag gypsum board> The slag gypsum board is a material classified as a fiber-reinforced cement board specified in JIS A5430, and in addition to slag and gypsum, it has organic fibers mainly composed of waste paper. Specifically, the slag gypsum board is a non-combustible material mixed with 1 to 5 wt% or less of organic fibers (waste paper), and contains 30 to 50 wt% of blast furnace slag, 30 to 50 wt% of gypsum dihydrate, and 5 wt% or less of waste paper. The slag gypsum board is a material with high hardness from before heating and maintains the same hardness during heating as before heating. Since the slag gypsum board contains highly tough organic fibers, the occurrence of cracks due to heating is extremely small, and breakage can be prevented. In addition, the inflow of heat from the cracks to the back surface can be reduced.

[0030] The slag gypsum board contains free water and crystal water, and the bulk density is 0.90 g / cm 3 above 1.20 g / cm 3 less, and as an example, those stored in an environment of 23°C and 50% RH were 1.17 g / cm 3 . The slag gypsum board has a moisture ratio derived from free water and crystal water of about 13.2%, and the amount of free water and crystal water is 0.16 g / cm 3This is an example of a sample stored at 23°C and 50% RH. The amount of free water and crystal water contained in the slag gypsum board is equal to or greater than that of reinforced gypsum board in the same volume. In an example where slag gypsum board was used as the first coating material, the maximum temperature reached by the slag gypsum board was approximately 300°C.

[0031] Here, crystalline water refers to water that is chemically bonded to the material components in slag gypsum board, and is different from water that is not chemically bonded (free water). The gypsum in slag gypsum board is dihydrate gypsum (CaSO4·2H2O), similar to the gypsum in reinforced gypsum board, and becomes hemihydrate gypsum (CaSO4·1 / 2H2O) while releasing water when heated. When hemihydrate gypsum is heated, it becomes anhydrous gypsum (CaSO4) while releasing water. The crystalline water contained in the gypsum exhibits fire-resistant properties, making it usable as a fire-resistant material. For slag gypsum board, the amount of water was defined as the mass loss from room temperature to 200°C.

[0032] Furthermore, the gypsum and blast furnace slag contained in slag gypsum boards are by-products, and while discarding them as is would be an environmental burden, using them in slag gypsum boards helps reduce the environmental impact. In addition, the waste paper used in slag gypsum boards is also a recycled material. Since 87% of the material used in slag gypsum boards is recycled, it can reduce CO2 emissions.

[0033] <Wood wool cement board> Wood wool cement board is a material classified as a wood-based cement board as defined in JIS A5404. For example, it is a semi-noncombustible material that uses 100% domestically produced cypress thinnings as organic fibers. Specifically, wood wool cement board is a semi-noncombustible material that contains 1 to 30 wt% or less of organic fibers (wood wool), with 70 wt% or more of cement and 30 wt% or less of wood wool. Wood wool cement board is a material that has hardness even before heating, and maintains the same hardness during heating as before heating.

[0034] Because wood wool cement board contains highly tough organic fibers, it is extremely resistant to cracking due to heating, thus enhancing impact resistance. The wood wool cement board contains free water and crystalline water, and has a bulk density of 1.0 g / cm³. 3 As an example, when stored at 23°C and 50% RH, the concentration was 1.13 g / cm³. 3 The wood wool cement board had a moisture content of approximately 7.0% derived from free water and crystal water, and the amount of free water and crystal water was 0.08 g / cm³. 3 This is an example of a sample stored at 23°C and 50% RH. For the wood wool cement board, the mass loss from room temperature to 200°C was considered to be the amount of moisture. In addition, as one example, the maximum temperature reached by the wood wool cement board is approximately 300°C.

[0035] In wood wool cement boards, decomposition of the crystalline water in the hardened cement paste occurs at around 450°C. However, when wood wool cement boards are used to cover the inside of calcium silicate boards, depending on the heating conditions, the wood wool cement boards may not reach 450°C, and decomposition of the crystalline water may not occur.

[0036] The bulk density of reinforced gypsum board is 0.75-0.95 g / cm³. 3 For example, a sample stored at 23°C and 50% RH contains approximately 0.79 g / cm³. 3 That was the case.

[0037] <Second covering material> The second covering material 12 is formed in a cylindrical shape in cross-section so as to cover the outer surface of the first covering material 11. The second covering material 12 is formed of, for example, a calcium silicate board.

[0038] As shown in Figure 2, the second covering material 12 is composed of a plurality of plate-like members, and each plate-like member is fixed to the first covering material 11 by a second fastener 22 such as a screw. When the first covering material 11 and the second covering material 12 are firmly fixed to the wooden structural core material 10, the second fastener 22 penetrates the second covering material 12 in the thickness direction, and its tip is inserted into the first covering material 11. It is desirable that the second fastener 22 penetrates the first covering material 11 and the second covering material 12 in the thickness direction and is inserted into the wooden structural core material 10. It is desirable that the second fastener 22 be located at least 30 mm away from the corners of the wooden structural core material 10, for example. It is preferable to use stainless steel, which has a lower thermal conductivity than iron, as the material for the second fastener 22.

[0039] <Calcium silicate board> The calcium silicate board according to the embodiment of the present invention is a non-combustible material belonging to the xonotlite system, exhibiting minimal structural change due to heating shrinkage and high fire resistance and heat insulation properties. It contains 65-80 wt% calcium silicate, less than 10 wt% calcium hydroxide, and less than 3 wt% crystalline silica (quartz). The calcium silicate board maintains a low thermal conductivity from low to high temperatures, meaning it is a material with high heat insulation properties, and its fire resistance temperature is approximately 1000°C. The calcium silicate board contains moisture and has a bulk density of 0.15 g / cm³. 3 More than 0.70g / cm 3 It is less than 0.30 g / cm³, for example, when stored at 23°C and 50% RH. 3 Furthermore, the calcium silicate board had a water content of approximately 2.2% (less than 3.0%) derived from free water and crystal water, and a water content of 0.007 g / cm³. 3 This is an example of a sample stored at 23°C and 50% RH. Since calcium silicate plates contain virtually no crystal water, the amount of water was determined by the mass loss due to drying at 105°C.

[0040] <Surface material> The surface material 13 is formed in a cylindrical shape in cross-section so as to surround the second covering material 12. The surface material 13 can be made of, for example, wood formed into a general plate shape, and the material is not particularly limited. The surface of the surface material 13 may be coated not only with paint to enhance weather resistance, durability, and aesthetics, but also with boric acid-based or phosphoric acid-based chemicals. Boric acid-based and phosphoric acid-based chemicals release moisture when heated, slowing the temperature rise of the present invention in the event of a fire and improving fire resistance.

[0041] The surface material 13 is fixed to the first covering material 11 and the second covering material 12 by a third fastener (fixing member) 23 such as a screw. The tip of the third fastener 23 is positioned inside the first covering material 11 so as not to penetrate the first covering material 11. That is, the third fastener 23 penetrates the surface material 13, the second covering material 12, and the first covering material 11 in this order in the thickness direction, and its tip does not reach the wood structural core material 10.

[0042] Furthermore, when the first covering material 11 and the second covering material 12 are firmly fixed to the wooden structural core material 10, it is desirable that the third fastener 23 penetrates the first covering material 11 and the second covering material 12 and is inserted into the wooden structural core material 10. It is desirable that the third fastener 23 be located at least 30 mm away from the corner of the wooden structural core material 10. It is preferable to use stainless steel, which has a lower thermal conductivity than iron, as the material for the third fastener 23.

[0043] Furthermore, the third fastener 23 may be fitted with a wooden plug 23a to conceal the screw head, or non-combustible wood or material may be used instead of the wooden plug 23a. The wooden plug 23a, non-combustible wood, or non-combustible material fitted to the screw head in this way can reduce thermal bridging of the screw.

[0044] Here, the changes in the wood fire-resistant structure 1 as heating progresses during a fire will be explained based on Figures 3 and 4. Figure 3(a) is a schematic enlarged cross-sectional view of the wood fire-resistant structure 1 before heating, Figure 3(b) is a schematic enlarged cross-sectional view of the wood fire-resistant structure in the first stage of heating, Figure 4(a) is a schematic enlarged cross-sectional view of the wood fire-resistant structure in the second stage of heating, and Figure 4(b) is a schematic enlarged cross-sectional view of the wood fire-resistant structure in the third stage of heating.

[0045] As shown in Figure 3(a), before heating, the first coating material 11 and the surface material 13 contain a large amount of moisture W (see circles in the figure). The second coating material 12, which is placed for the purpose of heat insulation, contains almost no moisture. In the first stage during heating shown in Figure 3(b), the surface material 13, which is heated from the outside by a flame or the like, carbonizes, and the moisture in the heated first coating material 11 decreases.

[0046] In the second stage of heating shown in Figure 4(a), the carbonized surface material 13 burns away, and the moisture content in the first coating material 11 heated via the second coating material 12 further decreases. Furthermore, in the third stage of heating shown in Figure 4(b), the moisture content in the first coating material 11 heated via the second coating material 12 further decreases. It is believed that as long as the first coating material 11 retains free water and crystal water, the first coating material 11 can suppress the temperature rise of the wood structural core material 10 and keep it below the carbonization temperature of the wood structural core material 10 (approximately 260°C). Therefore, a higher moisture content in the first coating material 11 is desirable. However, as shown in Figure 4(b), even if the moisture content in the first coating material 11 and the second coating material 12 decreases, they can still maintain their fire-resistant coating performance as insulating materials.

[0047] To improve the fire resistance of the wood fire-resistant structure 1, it is important that at least one of the first covering material 11 and the second covering material 12 has a high moisture content, in other words, that its temperature does not rise easily. Below, we will compare and explain the materials that make up the first covering material 11 or the second covering material 12.

[0048] This paper describes the thermal conductivity, linear shrinkage rate, apparent volumetric specific heat, and heat required for temperature rise of the slag gypsum board used in the first coating material 11 and the calcium silicate board used in the second coating material 12. For comparison, conventionally used reinforced gypsum board is also described.

[0049] Figure 5 is a graph showing the relationship between temperature and thermal conductivity for slag gypsum board, calcium silicate board, and reinforced gypsum board. The lower the thermal conductivity, the less heat is transferred, and the calcium silicate board had the lowest thermal conductivity. For example, it is thought that using calcium silicate board as the second coating material 12 has the effect of suppressing the inflow of heat into the interior.

[0050] Figure 6 is a graph showing the relationship between the temperature of slag gypsum board, calcium silicate board, and reinforced gypsum board and the linear shrinkage rate of the coating material due to heating. For all materials, the linear shrinkage rate gradually increased with increasing temperature within the range from room temperature to approximately 600°C, and above 600°C, the linear shrinkage rate of reinforced gypsum board and slag gypsum board increased sharply.

[0051] The linear shrinkage rate is thought to affect how easily joints open and how easily cracks form, and calcium silicate board had the smallest linear shrinkage rate. By using calcium silicate board for the outer fire-resistant coating layer (second coating material 12), which is prone to high temperatures, it is thought that the inflow of heat into the interior due to joint opening and cracking can be suppressed.

[0052] Figure 7 is a graph showing the relationship between the temperature of slag gypsum board, calcium silicate board, and reinforced gypsum board and the apparent volumetric specific heat, which represents the resistance to temperature rise. The apparent volumetric specific heat of reinforced gypsum board and slag gypsum board increased significantly at approximately 100-200°C. This is thought to be due to the latent heat of vaporization of the crystal water contained in the reinforced gypsum board and slag gypsum board.

[0053] The greater the amount of free water and crystal water contained in slag gypsum board, reinforced gypsum board, and calcium silicate board, the greater the apparent volumetric specific heat, and the greater the apparent volumetric specific heat, the slower the temperature rises. The guideline for the carbonization temperature of wood used as the core material 10 for wood structures is approximately 260°C, but by using slag gypsum board, which does not easily reach a temperature of approximately 100-200°C, as the inner first coating material 11, it is thought that the time it takes for the surface of the core material 10 for wood structures to reach the carbonization temperature is extended.

[0054] Figure 8 shows the relationship between the temperature rise of slag gypsum board, calcium silicate board, and reinforced gypsum board and the amount of heat required to achieve that temperature rise. The temperature rise range was calculated from the apparent volumetric specific heat for four ranges: 20°C to 260°C, 20°C to 300°C, 20°C to 400°C, and 20°C to 500°C.

[0055] As shown in Figure 8, it was confirmed that in all temperature ranges, the amount of heat required to raise the temperature was greatest for slag gypsum board, followed by reinforced gypsum board and then calcium silicate board. The greater the amount of heat required to raise the temperature, the more difficult it is for the temperature to rise. In the temperature range shown in the graph, the amount of heat required to raise the temperature was greatest for slag gypsum board in all cases. From this, it was confirmed that slag gypsum board heats up more slowly than reinforced gypsum board.

[0056] As described above, in the fire-resistant wooden structure 1 according to this embodiment, the first covering material 11 covering the outer surface of the wooden structural core material 10 contains organic fibers, free water, or crystalline water, and the proportion of water derived from free water or crystalline water is 6.0% or more, and the second covering material 12 covering the outer surface of the first covering material 11 has a proportion of water derived from free water or crystalline water of 3.0% or less. Furthermore, the first covering material 11 is made of either slag gypsum board or wood wool cement board, and the second covering material 12 is made of calcium silicate board.

[0057] As a result, the core material 10 for the wood structure is covered with a first and second covering material 11 and a second covering material 12, which have high fire resistance, in a layered structure. Therefore, a wood fire-resistant structure 1 can be obtained that ensures fire resistance and excellent workability.

[0058] Here, the bulk density of the second coating material 12 is 0.15 g / cm³. 3 More than 0.70g / cm 3 It is less than [amount missing]. This makes it possible to improve workability by using a second covering material 12 that has a lower bulk density and is lighter than reinforced gypsum board.

[0059] Furthermore, the fire-resistant wooden structure 1 is further equipped with a surface material 13 that covers the outer surface of the second covering material 12. The surface material 13 is fixed to the first covering material 11 and the second covering material 12 by a third fastener (fixing member) 23, and the tip of the third fastener 23 is positioned inside the first covering material 11 so as not to penetrate the first covering material 11. This prevents the fixing member from becoming a thermal bridge that carbonizes the core material of the wooden structure during a fire. Therefore, the fire resistance of the fire-resistant wooden structure 1 can be further improved.

[0060] Furthermore, the surface material 13 is fixed to the wood structural core material by a third fastener 23 that penetrates the first covering material 11 and the second covering material 12. This causes the third fastener 23 to integrate the surface material 13, the first covering material 11, the second covering material 12, and the wood structural core material 10. Thus, the overall strength of the wood fire-resistant structure can be ensured.

[0061] Furthermore, the thickness of the first covering material 11 is three times or less the thickness of the second covering material 12, or the thickness of the second covering material 12 is three times or less the thickness of the first covering material 11, or the first covering material 11 has the same thickness as the second covering material 12. In any of these cases, the core material 10 for the wood structure can be covered with a highly fire-resistant material to form a layered structure. Therefore, in any of these cases, the fire resistance of the wood fire-resistant structure 1 can be further improved.

[0062] Furthermore, when the first covering material 11 is slag gypsum board and the second covering material 12 is calcium silicate board, the thickness of the first covering material 11 is 10 mm to 30 mm, and the thickness of the second covering material 12 is 10 mm to 30 mm. Also, when the first covering material 11 is wood wool cement board and the second covering material 12 is calcium silicate board, the thickness of the first covering material 11 is 10 mm to 20 mm, and the thickness of the second covering material 12 is 20 mm to 30 mm. In other words, by using a non-combustible first covering material 11 and a lightweight calcium silicate board in combination within the above thickness ranges, fire resistance and excellent workability can be ensured.

[0063] Next, a fire resistance experiment to confirm the fire resistance performance of the wood fire-resistant structure 1 according to the embodiment will be described. The wood fire-resistant structure 1, used as a test specimen, was placed in a heating furnace and heated for 1 hour according to a standard heating temperature curve. After heating was stopped, it was allowed to cool for approximately 180 minutes (see Figure 10).

[0064] As shown in Figure 9, the measurement points in the fire-resistant wooden structure 1 were eight locations A1 to A8 inside the fire-resistant wooden structure 1. Specifically, the corner temperature was measured at four locations A1, A3, A5, and A7, and the flat surface temperature was measured at four locations A2, A4, A6, and A8.

[0065] The results of the fire resistance test are shown in Figure 11. From the experimental results, the temperature of the wood fire-resistant structure 1 was higher at the corners (A1, A3, A5, A7) than at the flat surfaces (A2, A4, A6, A8), and at all measurement points, the temperature was below the carbonization temperature guideline of 260°C for the wood structural core material 10. Furthermore, after the experiment, the covering material was removed and the condition of the wood structural core material 10 was checked, and there was no carbonization in the wood structural core material 10, confirming that the present invention has fire-resistant properties. <Test specimen specifications> • Core material for wood structural (laminated timber), 600mm x 600mm • Slag gypsum board, 12mm thick Calcium silicate board, 30mm thick • Surface material (laminated wood), 18mm thick [Examples]

[0066] (Example 1) An elemental test specimen of the wood fire-resistant structure 1 was prepared by arranging the wood structural core material 10, the first covering material 11, and the second covering material 12 in that order from the inside out. Slag gypsum board was used for the first covering material 11, and calcium silicate board was used for the second covering material 12. <Test specimen specifications> • Core material for wood structural components (sawn lumber), 60mm thick • Slag gypsum board, 30mm thick Calcium silicate board, 10mm thick

[0067] (Examples 2-3) Examples 2 and 3 are similar to Example 1 except for the difference in the thickness of the first coating material 11 and the second coating material 12. Specifically, in Example 2, a 20 mm thick slag gypsum board was used for the first coating material 11, and a 20 mm thick calcium silicate board was used for the second coating material 12. In Example 3, a 10 mm thick slag gypsum board was used for the first coating material 11, and a 30 mm thick calcium silicate board was used for the second coating material 12.

[0068] (Comparative Examples 1-4) Comparative Example 1 used only 40mm thick slag gypsum board. Comparative Example 2 used only 40mm thick calcium silicate board. Comparative Example 3 used a 20mm thick calcium silicate board for the first coating material 11 and a 20mm thick slag gypsum board for the second coating material 12. Comparative Example 4 used only 40mm thick reinforced gypsum board.

[0069] (Examples 4-5) Next, examples and comparative examples of a wood-based fire-resistant structure 1 in which the first covering material 11 is made of wood wool cement board and the second covering material 12 is made of calcium silicate board will be described. In Examples 4 and 5, elemental test specimens of the wood-based fire-resistant structure 1 were prepared by arranging the wood structural core material 10, the first covering material 11, and the second covering material 12 in that order from the inside. Wood wool cement board was used for the first covering material 11, and calcium silicate board was used for the second covering material 12. <Test specimen specifications> • Core material for wood structural components (sawn lumber), 60mm thick • Wood wool cement board Calcium silicate board

[0070] Example 4 used a 20mm thick wood wool cement board and a 20mm thick calcium silicate board. Example 5 used a 10mm thick wood wool cement board and a 30mm thick calcium silicate board.

[0071] (Comparative Example 5) Comparative Example 5 used only a 40 mm thick wood wool cement board. The experimental conditions for Examples 1-5 and Comparative Examples 1-5 are shown in Table 1.

[0072] <Rating> In Examples 1-5 and Comparative Examples 1-5, the wood was heated in a small electric furnace, and the time elapsed until the surface temperature reached 260°C was measured. Furthermore, the constructability was evaluated based on the total weight of the wood fire-resistant structure 1. The evaluation results are shown in Table 1.

[0073] [Table 1]

[0074] Examples 1-3 showed a longer time to reach a surface temperature of 260°C compared to Comparative Examples 1-5. In particular, Examples 1 and 2 took longer to reach a surface temperature of 260°C than the other examples and Comparative Examples 1-4. Furthermore, by combining with calcium silicate boards, weight reduction can be achieved, thereby improving workability.

[0075] Thus, the overall evaluation of Examples 1 to 3, in which the fire-resistant covering material located on the inside of the wood fire-resistant structure 1 was slag gypsum board and the fire-resistant covering material located on the outside was calcium silicate board, was a "○" (good), and it was confirmed that both the fire resistance performance and workability were satisfied compared to Comparative Examples 1 to 5, which received an "×" (bad) overall evaluation.

[0076] Examples 4 and 5 showed a longer time to reach a surface temperature of 260°C compared to Comparative Examples 2 to 5. Furthermore, by combining them with calcium silicate boards, weight reduction can be achieved, thereby improving workability. Comparative Example 1 also showed a longer time to reach a surface temperature of 260°C than Examples 4 and 5, but because it was composed solely of slag gypsum boards, weight reduction was difficult, resulting in poor workability.

[0077] Thus, the overall evaluation of Examples 4-5, in which the fire-resistant covering material located on the inside of the wood fire-resistant structure 1 was wood wool cement board and the fire-resistant covering material located on the outside was calcium silicate board, was a "○" (good), and it was confirmed that both the fire resistance performance and workability were satisfied compared to Comparative Examples 1-5, which received an "×" (bad) overall evaluation.

[0078] While embodiments of the present invention have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments, and any design modifications that do not depart from the spirit of the present invention are included in the present invention.

[0079] For example, in the above embodiment, the fixing of the wood structural core material 10 to the first covering material 11, the fixing of the first covering material 11 to the second covering material 12, and the fixing of the second covering material 12 to the surface material 13 may be done by screws alone, by adhesive alone, or by a combination of screws and adhesive.

[0080] Furthermore, in the above embodiment, the first covering material 11, the second covering material 12, and the surface material 13 are all made of single-layer plate-like members, but multiple plate-like members may be stacked in the thickness direction. Also, the first covering material 11 and the second covering material 12 may each be applied as a single layer or as multiple layers. Specifically, the second covering material 12, which is positioned to cover the periphery of the first covering material 11, may be further covered with the first covering material 11, or the periphery of the first covering material 11 may be further covered with the second covering material 12. In addition, the wood structural core material 10 may be coated to enhance its durability. [Explanation of symbols]

[0081] 1: Wooden fireproof structure 10: Core material for wood-based structures 11:First covering material 12:Second covering material 13: Surface material

Claims

1. A fire-resistant wooden structure used for columns, beams, or walls of a building, A core material for wooden structures that supports loads, A first covering material that covers the outer surface of the aforementioned wood structural core material, The system comprises a second covering material that covers the outer surface of the first covering material, The first coating material contains organic fibers, free water, or crystal water, and the proportion of water derived from free water or crystal water is 6.0% or more. The second coating material has a water content of 3.0% or less derived from free water or crystal water. A wood-based fire-resistant structure characterized by the following features.

2. The bulk density of the second coating material is 0.15 g / cm³. ３ 0.70g / cm or more ３ A wood fire-resistant structure according to claim 1, characterized in that it is less than [amount missing].

3. A fire-resistant wooden structure used for columns, beams, or walls of a building, A core material for wooden structures that supports loads, A first covering material that covers the outer surface of the aforementioned wood structural core material, The system comprises a second covering material that covers the outer surface of the first covering material, The first covering material is made of slag gypsum board, The second coating material is made of calcium silicate board. A wood-based fire-resistant structure characterized by the following features.

4. A fire-resistant wooden structure used for columns, beams, or walls of a building, A core material for wooden structures that supports loads, A first covering material that covers the outer surface of the aforementioned wood structural core material, The system comprises a second covering material that covers the outer surface of the first covering material, The first covering material is made of wood wool cement board, The second coating material is made of calcium silicate board. A wood-based fire-resistant structure characterized by the following features.

5. The second covering material further comprises a surface material that covers the outer circumferential surface, The surface material is fixed to the first covering material and the second covering material by a fixing member. The wood fire-resistant structure according to any one of claims 1 to 4, characterized in that the tip of the fixing member is positioned inside the first covering material so as not to penetrate the first covering material.

6. The second covering material further comprises a surface material that covers the outer circumferential surface, The wood fire-resistant structure according to any one of claims 1 to 4, characterized in that the surface material is fixed to the wood structural core material by a fixing member that penetrates the first covering material and the second covering material.

7. The wood fire-resistant structure according to any one of claims 1 to 4, characterized in that the thickness of the first covering material is three times or less the thickness of the second covering material.

8. The wood fire-resistant structure according to any one of claims 1 to 4, characterized in that the thickness of the second covering material is three times or less the thickness of the first covering material.

9. The wood fire-resistant structure according to any one of claims 1 to 4, characterized in that the first covering material has the same thickness as the second covering material.

10. The thickness of the first covering material is 10 mm or more and 30 mm or less. The wood fire-resistant structure according to claim 3, characterized in that the thickness of the second covering material is 10 mm or more and 30 mm or less.

11. The thickness of the first covering material is 10 mm or more and 20 mm or less. The wood fire-resistant structure according to claim 4, characterized in that the thickness of the second covering material is 20 mm or more and 30 mm or less.

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