Method for determining depth position of fire-resistant structural materials and fixing members

Abstract

To provide a fire-resistant structural material capable of reliably stopping carbonization at a fire-stopping portion even when a metal fixing member is used. [Solution] This fire-resistant structural material comprises a load-bearing part 2 made of wood at its center, a fire-stopping part 3 located on the outside of the load-bearing part 2, and an intumescent fire-resistant layer 4 provided on the outside of the fire-stopping part 3. A metal fixing member 7 penetrates the fire-stopping part 3 from the side of the fire-stopping part 3 toward the load-bearing part 2, reaching the inside of the load-bearing part 2. In a preliminary fire resistance test based on ISO 834, the char depth [Cg] of the charred part of the fire-stopping part 3 in the area where the fixing member 7 was not present, and the length [Lc] from the boundary B between the charred and uncharred parts of the fire-stopping part 3 to the end of the fixing member 7 on the load-bearing part 2 side, satisfy the following formula (1): Lc>Cg …(1)

Description

[Technical Field]

[0001] The present invention relates to a fire-resistant structural material and a method for determining the depth position of a fixing member. [Background technology]

[0002] In wooden buildings, the structural materials that make up the columns and beams are required to be fire-resistant so that they do not collapse even in the event of a fire. It is desirable that the center (load-bearing portion) that supports the load of a structural material does not carbonize even when the surface is burned by exposure to flames. To achieve this, a fire-resistant structure has been studied that includes, for example, a fire-stop portion impregnated with a fire-retardant treatment agent and a surface layer that does not contain the fire-retardant treatment agent (Patent Document 1). This fire-resistant structure can prevent carbonization from progressing toward the center after the fire has ended by adjusting the thickness of the fire-stop portion so that the burning portion at the end of the fire is limited to the portion injected with the fire-retardant treatment agent, thereby naturally stopping the fire and preventing the building from collapsing. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4958098 Summary of the Invention [Problem to be solved by the invention]

[0004] When metal fastening members such as screws or nails are used to fasten fire-stopping layers or other components to load-bearing sections, the fastening members can form thermal bridges during a fire, transferring heat to the load-bearing sections and potentially carbonizing them. Therefore, the present invention aims to provide a fire-resistant structural material that can reliably prevent carbonization at the fire-stopping sections, even when metal fastening members are used. Another aim is to provide a method for determining the depth position of fastening members to provide such a fire-resistant structural material. [Means for solving the problem]

[0005] The present invention provides a fire-resistant structural material comprising a load-bearing section made of wood at its center and having a substantially rectangular cross section, a fire-stopping section located on the outside of the load-bearing section, and an intumescent fire-resistant layer provided on the outside of the fire-stopping section, wherein at least the outermost part of the fire-stopping section is made of wood, and a metal fixing member penetrates the fire-stopping section from the fire-stopping section side toward the load-bearing section, reaching the inside of the load-bearing section, and in a preliminary fire resistance test based on ISO 834, the char depth [Cg] of the charred part of the fire-stopping section in a location where the fixing member is not present and the length [Lc] from the boundary between the charred and uncharred parts of the fire-stopping section to the end of the fixing member on the load-bearing section side satisfy the following formula (1): Lc>Cg …(1)

[0006] Generally, when a fire-resistant structural material is exposed to the heat of a fire, carbonization of the wood progresses from the surface of the fire-resistant structural material, and the metal fixing members heat up, forming thermal bridges, which tend to carbonize quickly and deeply in the areas where the fixing members are in contact. In the fire-resistant structural material of the present invention, the metal fixing members also form thermal bridges, transmitting heat to the load-bearing parts. However, because the relationship of formula (1) is satisfied, the heat is dispersed over a wide area centered on the areas where the fixing members are in contact, making it difficult for the temperature of the load-bearing parts to reach a carbonizing temperature. Therefore, even when metal fixing members are used, carbonization can be reliably stopped at the fire-stopping parts.

[0007] The fire-resistant structural material of the present invention may have at least one of the following characteristics. The load-bearing section and the flame-stopping section are independent components. ·Lc in the above formula (1) is 10 mm or more. -A foam fire-resistant layer is also provided on the surface of the end of the fixing member on the fire-stop side. The end of the fixing member on the fire-stopping part side is located inside the fire-stopping part and in the part that will char during the fire resistance test, and a plug is placed to fill the gap between the end and the surface of the fire-stopping part. The fire-stopping section is made of wood impregnated with a fire-retardant agent. The fire-resistant structural materials are components that make up columns, beams, walls, and ceilings.

[0008] The present invention also provides a method for determining the depth position of a fixing member for a fire-resistant structural material comprising a load-bearing section made of wood at the center and having a substantially rectangular cross section, a fire-stopping section located on the outside of the load-bearing section, and an intumescent fire-resistant layer provided on the outside of the fire-stopping section, where at least the outermost part of the fire-stopping section is made of wood.When a metal fixing member is applied from the fire-stopping section side towards the load-bearing section so as to penetrate the fire-stopping section and reach the inside of the load-bearing section, the method determines the length of the fixing member to be applied and the depth position of the end part on the fire-stopping section side so that in a preliminary fire resistance test based on ISO 834, the char depth [Cg] of the charred part of the fire-stopping section where the fixing member is not present and the length [Lc] from the boundary between the charred and uncharred parts of the fire-stopping section to the end part on the load-bearing section side of the fixing member satisfy the following formula (1): Lc>Cg …(1)

[0009] This method makes it possible to determine the depth position of the fixing member that will prevent the load-bearing portion from carbonizing when the fire-resistant structural material is exposed to the heat of a fire and will reliably stop carbonization at the fire-extinguishing portion. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a fire-resistant structural material that can reliably stop carbonization at the fire-stop portion even when using metal fixing members, and a method for determining the depth position of fixing members for providing such a fire-resistant structural material. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a cross-sectional view of a fire-resistant structural material according to a first embodiment of the present invention. [Figure 2] 1(a) to 1(f) are cross-sectional views showing embodiments of the fixing member. [Figure 3] 10A and 10B are diagrams showing various dimensions of the fixing member and the carbonized portion. [Figure 4] FIG. 4 is a cross-sectional view of a fire-resistant structural material according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] The fire-resistant structural material of the present invention is made of wood and is intended to be used primarily as pillars, beams, walls, and ceilings, and to improve the fire resistance of such structures. Preferred embodiments of the present invention will be described in detail below with reference to the drawings. Note that the same or corresponding parts in each drawing will be designated by the same reference numerals, and duplicate explanations will be omitted.

[0013] First Embodiment A first embodiment of the present invention is an embodiment in which the load-bearing portion and the flame-extinguishing portion are independent members.

[0014] As shown in Figure 1, the fire-resistant structural material 1A of this embodiment is an example of a column, and includes a long load-bearing portion 2 with a square cross section, a fire-stopping portion 3 provided on the outside of the load-bearing portion 2, and an intumescent fire-resistant layer 4 provided on the outside of the fire-stopping portion 3. Here, "outside" refers to the side that is visible externally in the radial direction of the fire-resistant structural material 1A. In the fire-resistant structural material 1A, the fire-stopping portion 3 is arranged so as to surround the entire outer periphery of the side surface of the load-bearing portion 2, which forms the center of the fire-resistant structural material 1A, and the intumescent fire-resistant layer 4 is arranged so as to surround the entire outer periphery of the fire-stopping portion 3.

[0015] The load-bearing portion 2 is a core portion that supports the load of the building. The load-bearing portion 2 is made of wood, and the specific type and density of the wood may be the same as that used for the fire-stopping portion 3 described below, or a tree species with a higher density and better structural performance may be used. The size of the cross section of the load-bearing portion 2 may be 120 mm to 1200 mm, 180 mm to 560 mm, or 240 mm to 440 mm as one side of a square. When the fire-resistant structural material 1A is a beam, the beam cross section may have a beam depth of 120 mm to 1200 mm and a beam width of 120 mm to 480 mm. The wall cross section may have a wall thickness of 90 mm to 210 mm.

[0016] Although the load-bearing portion 2 is depicted as a single piece of solid wood in FIG. 1, the load-bearing portion 2 may be made of laminated wood in which a plurality of laminas are stacked, CLT, LVL, or the like.

[0017] The fire-stopping portion 3 functions as a layer that stops the progression of carbonization of the fire-resistant structural material 1A in the event of a fire, and is designed to be thick enough that it will not burn up completely in its thickness direction even during a fire. Materials that make up the fire-stopping portion 3 include not only conventional wood, but also wood injected with a fire-retardant treatment agent. Alternatively, the outermost portion may be made of wood, and the side closer to the load-bearing portion 2 may be made of a non-flammable inorganic material or foam material such as gypsum board, calcium silicate board, or mortar. In this case, the thickness is preferably set to a thickness that will stop the fire with the inorganic material layer.

[0018] Generally, the greater the density of wood, the greater its heat capacity and the easier it is to stop burning. Therefore, the density of the wood that makes up the fire-stopping portion 3 is 350 kg / m 3 It is preferable that the saturation is 450 kg / m or more. 3 More preferably, it is 480 kg / m or more. 3 The upper limit is preferably 600 kg / m or more. 3 , 580 kg / m 3 , 550 kg / m 3 Examples of wood having such a density include cedar, larch, cypress, fir, Japanese cypress, white pine, Yezo spruce, camphor tree, red pine, etc. Larch is preferred in terms of abundance of resources and market price.

[0019] The wood that forms the fire-stopping portion 3 has a density of 400 kg / m3 so that it can be easily impregnated with fire-retardant chemicals. 3 The density may be less than 390 kg / m 3 may be less than 380 kg / m 3 The lower limit of the density is 250 kg / m 3 , 270 kg / m 3 , 290 kg / m 3Examples of wood with such a density include cedar, Paulownia, and Japanese black pine. When wood with a low density is selected, it may be necessary to make the fire-stopping portion 3 thicker than when wood with a high density is selected. Cedar is suitable in terms of abundance of resources and market price.

[0020] The fire retardant treatment agent injected into the wood that constitutes the fire-stopping portion 3 can be any type, including phosphorus-based, nitrogen-based, boron-based, and halogen-based agents. The method for injecting the fire retardant treatment agent into the wood can be any method, including dipping, painting, spraying, and vacuum / pressure treatment.

[0021] The thickness of the fire-stopping portion 3 varies depending on the type of wood that makes up the fire-stopping portion 3 and the desired fire resistance time, but for example, if 60 minutes of fire resistance is desired, it is preferably 25 mm to 65 mm, more preferably 35 mm to 55 mm. If 90 minutes of fire resistance is desired, it is preferably 30 mm to 70 mm, more preferably 40 mm to 60 mm.

[0022] In this embodiment, the fire-retardant portion 3 is made up of four fire-retardant layers 3a that sandwich the load-supporting portion 2 from all sides. The fire-retardant layers 3a are fixed to the load-supporting portion 2 using a metal fixing member 7, which will be described later.

[0023] The intumescent fire-resistant layer 4 is a layer containing an intumescent fire-resistant agent. Examples of the intumescent fire-resistant agent include ammonium polyphosphate, ammonium phosphate, sodium silicate, melamine, and silicone. Polymers having reactive silicon groups

[0024] When the fireproofing agent is a solid, the intumescent fireproof layer 4 can be formed by dispersing the fireproofing agent in a resin to prepare a coating liquid, which is then applied to the surface of the fire-stopping portion 3. Methods for curing the resin include air drying, heating, and ultraviolet irradiation. By this method, the intumescent fireproof layer 4 can be laminated on the fire-stopping portion 3.

[0025] Alternatively, the intumescent fire-resistant layer 4 may be formed by laminating an intumescent fire-resistant sheet 4a, which has been formed into a sheet shape, onto the fire-stopping portion 3. When forming the intumescent fire-resistant sheet 4a into a sheet shape, it is preferable to prepare a liquid in which the fire-resistant agent is dispersed in resin, and then pour this into a predetermined space to form the sheet. Methods for laminating the intumescent fire-resistant sheet 4a onto the fire-stopping portion 3 include providing a layer of adhesive or adhesive material on the back of the sheet and attaching it to the fire-stopping portion 3, fixing the sheet to the fire-stopping portion 3 by driving fastening members such as screws into the sheet, and a combination of these methods. When driving fastening members, it is preferable to use fastening members that are shorter than the thickness of the fire-stopping portion 3 (i.e., do not penetrate the fire-stopping portion 3) so as not to reach the fire-resistant object.

[0026] The thickness of the intumescent fire-resistant layer 4 varies depending on the required fire resistance time. For example, when 60 minutes of fire resistance is required, the thickness of the intumescent fire-resistant layer 4 is 0.1 mm or more. This thickness may be 0.15 mm or more and 3.0 mm or less, or 0.2 mm or more and 2.5 mm or less. When 90 minutes of fire resistance is required, the thickness of the intumescent fire-resistant layer 4 is preferably 0.2 mm or more, and may be 0.3 mm or more and 6.0 mm or less, or 0.4 mm or more and 5.0 mm or less.

[0027] In fire-resistant structural material 1A, metal fixing member 7 penetrates fire-stop portion 3 toward load-supporting portion 2, reaching the inside of load-supporting portion 2. This fixes fire-stop portion 3 to load-supporting portion 2. The end of metal fixing member 7 on the fire-stopping portion 3 side is located inside fire-stopping portion 3, in a portion that will be carbonized in a fire resistance test, which will be described later.

[0028] The metallic fixing member (hereinafter simply referred to as "fixing member") 7 is preferably a shaft-shaped fixing member, examples of which include a screw, a nail, a drift pin, and a lag screw.

[0029] FIG. 2 shows an example of how the fixing member 7 is fastened. The fixing member 7 may be fastened after the intumescent fire-resistant layer 4 is provided (FIG. 2(a)). Then, for design considerations, the intumescent fire-resistant layer 4 may be provided on the surface of the end of the fixing member 7 on the fire-stopping portion 3 side (FIG. 2(b)). The intumescent fire-resistant layer 4 may be provided by applying a coating liquid of the material for the intumescent fire-resistant layer 4 to the end of the fixing member 7, or by patching a piece of intumescent fire-resistant sheet onto the end. The fixing member 7 may be fastened to secure the fire-stopping portion 3 to the load-supporting portion 2 before the intumescent fire-resistant layer 4 is provided. In this case, the intumescent fire-resistant layer 4 is then provided on the entire surface of the fire-stopping portion 3, including the end of the fixing member 7 (FIG. 2(c)).

[0030] Furthermore, the fixing member 7 may be fastened to the inside of the fire-stopping portion 3 after the intumescent fire-resistant layer 4 is provided. In this case, the step between the end of the fixing member 7 on the fire-stopping portion 3 side and the surface of the fire-stopping portion 3 is filled with a wooden plug 8 (FIG. 2(d)). After that, the intumescent fire-resistant layer 4 may be provided on the surface of the wooden plug 8 for design considerations. When providing the intumescent fire-resistant layer 4, a coating liquid of the material for the intumescent fire-resistant layer 4 may be applied to the end of the wooden plug 8, or a piece of an intumescent fire-resistant sheet may be patched onto the wooden plug 8. Note that the intumescent fire-resistant layer 4 may be provided before the intumescent fire-resistant layer 4 is provided. In this case, after the fixing member 7 is fastened, the intumescent fire-resistant layer 4 is provided on the entire surface of the fire-stopping portion 3, including the end of the wooden plug 8 (FIG. 2(e)).

[0031] In addition, in the case where the fire-stopping portion 3 is carved, the wooden plug 8 can be divided into two or used in combination with a different type of plug 8a made of a material that is more fire-resistant than wood (Figure 2(f)).

[0032] The length of the fixing member 7 is determined after a fire resistance test based on ISO 834 is conducted in advance. In the fire resistance test based on ISO 834, the fire-resistant structural material 1A of this embodiment was found to have a char depth [Cg] of the charred portion of the fire-stopping portion 3 in the carbonized portion (reference symbol D in FIG. 3) where the fixing member 7 is not present, and a length [Lc] from the boundary (reference symbol B in FIG. 3) between the charred and uncharred portions of the fire-stopping portion 3 to the end of the fixing member 7 on the load-supporting portion 2 side, as shown in FIG. 3, satisfy the following formula (1). The unit is the same for both sides, for example, mm. Lc>Cg …(1)

[0033] As shown in Figure 3, the char depth [Cs] at the location where the thermal bridge fixing member 7 is present is generally greater than the char depth [Cg] at the location where the fixing member 7 is not present. The difference between these values, i.e., the increase in char depth [Ci] due to the use of the fixing member 7, is preferably 5 mm or less, more preferably 4 mm or less, and even more preferably 3 mm or less. The smaller this value, the thinner the thickness of the fire-stop portion 3 can be. Furthermore, [Cg] is preferably 31 mm or less, more preferably 29 mm or less, and even more preferably 27 mm or less. [Lc] is preferably 10 mm or more, more preferably 20 mm or more, even more preferably 30 mm or more, and particularly preferably 35 mm or more.

[0034] In Fig. 3, [Ls] is the length (total length) of the fixing member 7, and [Lp] is the depth of the end of the fixing member 7 on the side of the fire-extinguishing portion 3. The sum of these is the depth [Lt] of the end of the fixing member 7 on the side of the load-supporting portion 2.

[0035] When applying fixing member 7 to fix flame-stop portion 3 to load-bearing portion 2, [Cg] and [Lc] are determined in advance through a fire resistance test based on ISO 834, and the length [Ls] of fixing member 7 and the depth [Lp] of the end portion on the flame-stop portion 3 side are determined so as to satisfy the above formula (1). In other words, the depth position of fixing member 7 can be determined by taking into consideration the four factors [Cg], [Lc], [Ls], and [Lp].

[0036] Generally, when a fire-resistant structural material is exposed to the heat of a fire, the wood carbonizes from its surface, and the metal fixing members heat up, forming thermal bridges, which tend to carbonize quickly and deeply in the areas where the fixing members are in contact. In the fire-resistant structural material 1A of this embodiment, the metal fixing members 7 also act as thermal bridges, transmitting heat to the load-bearing portion 2. However, because the relationship "Lc > Cg" is satisfied, the heat is dispersed over a wide area centered on the areas where the fixing members are in contact, making it difficult for the temperature of the load-bearing portion 2 to reach a carbonizing temperature. Therefore, even when a metal fixing member 7 is used, carbonization can be reliably stopped at the fire-stop portion.

[0037] Before the fire-stop portion 3 begins to carbonize, the intumescent fire-resistant layer 4 foams and expands due to the heat of the fire, providing a heat insulating effect. The fire-stop portion 3 burns and carbonizes, and the carbonization gradually spreads inside the fire-stop portion 3 toward the load-bearing portion 2, but the entire thickness does not burn, and the fire stops inside the fire-stop portion 3 some time after the fire is extinguished.

[0038] As described above, the relationship "Lc>Cg" and the function of the intumescent fire-resistant layer 4 ensure that carbonization is stopped at the fire-stopping portion 3, even when a metal fixing member 7 is used. Furthermore, the fire-resistant time of the fire-resistant structural material 1A can be extended without increasing the thickness of the fire-stopping portion 3.

[0039] Second Embodiment As a second embodiment of the present invention, an aspect in which the load-bearing portion and the flame-extinguishing portion are integrally formed will be described. The differences from the first embodiment will be mainly described as follows.

[0040] The fire-resistant structural material 1B shown in Figure 4 is made of laminated timber with eight laminated lamina 6 and has a square cross section. Each lamina 6 is bonded to the other lamina using an adhesive or the like. Resorcinol-based resin is a preferred adhesive material. The central part of this laminated timber is the load-bearing part 2, and the surrounding area is the fire-stopping part 3. The boundary between the load-bearing part 2 and the fire-stopping part 3 is determined by whether or not this part should be included in the structural calculations. The part to be included in the structural calculations is the load-bearing part 2.

[0041] The outside of the fire-stop portion 3 is provided with an intumescent fire-resistant layer 4, similar to the first embodiment.

[0042] In the fire-resistant structural material 1B, a metal fixing member 7 penetrates the fire-stopping portion 3 toward the load-supporting portion 2, reaching the inside of the load-supporting portion 2. This situation is similar to that of the first embodiment, but its purpose is different. That is, in the first embodiment, the fixing member 7 is used to fix the fire-stopping layer 3a, which is a component of the fire-stopping portion 3, to the load-supporting portion 2, but in this embodiment, the fixing member 7 is used to attach the bracket 9 to the fire-resistant structural material 1B.

[0043] The fire-resistant structural material 1B of this embodiment is easy to manufacture because the load-bearing portion 2 and the fire-stopping portion 3 can be constructed from laminated lumber of the lamina 6. In addition, because the bracket 9 can be fixed to the load-bearing portion 2, the bracket 9 will not fall off even if the fire-stopping portion 3 is carbonized during a fire.

[0044] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. For example, in the above embodiments, the load-bearing portion 2 has a square cross section, but the load-bearing portion may have a rectangular cross section, and may also be rectangular. Furthermore, the fire-resistant structural material is not limited to a column, but may also be a beam, wall, or ceiling. In the case of a beam, a fire-stopping portion is formed on three sides of the approximately rectangular shape, and in the case of a wall or ceiling, a fire-stopping layer is formed on one side of the approximately rectangular shape.

[0045] Furthermore, the fire-resistant structural material of the present invention may further include a finishing layer on the outside of the intumescent fire-resistant layer. That is, the finishing layer may be disposed so as to surround the entire periphery of the intumescent fire-resistant layer. The finishing layer is also called a decorative layer, and is a layer that building users come into contact with on a daily basis. Since the finishing layer may be touched by hand, if the fire-stopping portion contains a fire-retardant treatment agent, it acts as a lid to prevent the fire-retardant treatment agent from leaking out. Examples of materials that constitute the finishing layer include wood similar to the wood that constitutes the fire-stopping portion, and cedar or larch is particularly preferred.

[0046] The thickness of the finishing layer is preferably 20 mm to 40 mm, more preferably 25 mm to 35 mm, and even more preferably 28 mm to 33 mm. Since the production of a fire-stopping portion requires a lot of effort and expense, in order to improve the fire resistance of a fire-resistant structural material, the finishing layer, which is the outermost layer and can be produced relatively easily, should have a thickness within the above range, thereby easily allowing time for heat to be transferred to the interior. When the finishing layer is 30 mm or less in thickness, it does not interfere with the expansion of the intumescent fire-resistant layer, allowing the intumescent fire-resistant layer to fully demonstrate its performance. [Example]

[0047] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0048] [Comparative Example 1] A 0.5mm layer of fire-resistant paint (ammonium polyphosphate-based) was applied to a 100mm-thick piece of larch laminated timber that had not been injected with a fire-retardant treatment agent, and screws were then attached to it (as shown in Figure 2(a)). A one-hour fire resistance test (one-hour fire resistance test based on ISO 834 or JIS A 1304) was conducted, and the cross section of the screw attachment point was visually inspected to compare the char depth of the "general part" where no screws were attached and the "screw part" where screws were attached. The dimensional relationship between the screws and the test board is summarized in Table 1. The symbols have the following meanings. All measurements are in mm.

[0049] [Ls]: Screw length (total length) [Lp]: Screw embedment depth [Lt]: Reaching depth of the tip of the screw (= [Ls] + [Lp]) [Cg]: Carbonization depth of general part [Cs]: Carbonization depth of the screw [Lc]: Fixed length after carbonization [Ci]: Increase in carbonization depth of screw part (= [Cs] - [Cg])

[0050] [Comparative Examples 2 to 5, Example 1] The various values ​​were changed as shown in Table 1 and a fire resistance test was carried out.

[0051] [Example 2] A 0.4 mm thick layer of fire-resistant paint (ammonium polyphosphate-based) was applied to a 100 mm thick piece of larch laminated timber that had not been injected with a fire-retardant treatment agent, and a screw was then attached to the timber. 0.4 mm of fire-resistant paint was applied to the head of the screw (as shown in Figure 2(b)). Various values ​​were adjusted as shown in Table 1. A fire resistance test was then conducted in the same manner as in Comparative Example 1.

[0052] Comparative Example 6 A 0.4 mm thick layer of fire-resistant paint (ammonium polyphosphate) was applied to a 100 mm thick piece of larch laminated timber that had not been injected with a fire-retardant treatment agent, and a 1 cm deep recess was made. A screw was attached to the bottom of the recess. A wooden plug was inserted into the recess (as shown in Figure 2(d)). Various values ​​were adjusted as shown in Table 1. A fire resistance test was then conducted in the same manner as in Comparative Example 1.

[0053] [Example 3] A 0.4 mm thick layer of fire-resistant paint (ammonium polyphosphate) was applied to a 100 mm thick piece of larch laminated timber that had not been injected with a fire-retardant treatment agent, and a 2 cm deep recess was cut into the recess, with a screw attached to the bottom. A wooden plug was inserted into the recess (as shown in Figure 2(d)). Various values ​​were adjusted as shown in Table 1. A fire resistance test was then conducted in the same manner as in Comparative Example 1.

[0054] [Example 4] A 0.4 mm thick layer of fire-resistant paint (ammonium polyphosphate) was applied to a 100 mm thick piece of larch laminated timber that had not been injected with a fire-retardant treatment agent, and a 2 cm deep recess was cut into the recess, with screws attached to the bottom of the recess. The recess was plugged with a fire-resistant joint sealant containing a silicone resin ("Bond Fire-Resistant Joint Sealant" manufactured by Konishi Co., Ltd.) (as shown in Figure 2(d)). Various values ​​were adjusted as shown in Table 1. A fire resistance test was then conducted in the same manner as in Comparative Example 1.

[0055] [Example 5] A 0.4 mm thick layer of fire-resistant paint (ammonium polyphosphate) was applied to a 100 mm thick piece of larch laminated timber that had not been injected with a fire-retardant treatment agent, and a 4 cm deep recess was made. A screw was attached to the bottom of the recess. The recess was plugged with a fire-resistant joint sealant (as shown in Figure 2(d)). Various values ​​were adjusted as shown in Table 1. A fire resistance test was then conducted in the same manner as in Comparative Example 1.

[0056] [Example 6] A 0.4 mm thick layer of fire-resistant paint (ammonium polyphosphate) was applied to a 100 mm thick piece of larch laminated timber that had not been injected with a fire-retardant treatment agent, and a 2 cm deep recess was cut into the recess, with screws attached to the bottom of the recess. The recess was plugged with fire-resistant putty (Nitto Kasei Kogyo Co., Ltd.'s "Plaseal NF-11TF") (as shown in Figure 2(d)). Various values ​​were adjusted as shown in Table 1. A fire resistance test was then conducted in the same manner as in Comparative Example 1.

[0057] [Example 7] A 2cm deep recess was made in a 100mm thick piece of larch laminated timber that had not been injected with a fire retardant treatment agent, and a screw was attached to the bottom of the recess. A wooden plug was inserted into the recess, and a 0.4mm layer of fire-resistant paint (ammonium polyphosphate-based) was applied to the entire surface of the board (as shown in Figure 2(e)). Various values ​​were adjusted as shown in Table 1. A fire resistance test was then conducted in the same manner as in Comparative Example 1.

[0058] [Example 8] A 100-mm-thick laminated lumber of larch without injection of a flame-retardant treatment agent was carved out to a depth of 4 cm, and screws were attached at the bottom of the carved-out part. The carved-out part was plugged, and a fire-resistant paint (ammonium polyphosphate-based) was applied to the entire surface of the board to a thickness of 0.4 mm (the mode of Fig. 2(e)). Various numerical values were adjusted as shown in Table 1. Hereinafter, a fire resistance test was conducted in the same manner as in Comparative Example 1.

[0059] [Example 9] A fire-resistant paint (ammonium polyphosphate-based) was applied to a 100-mm-thick laminated lumber of larch without injection of a flame-retardant treatment agent to a thickness of 0.4 mm, and it was carved out to a depth of 2 cm, and screws were attached at the bottom of the carved-out part. The carved-out part was plugged with a 2-cm-thick plug made of a calcium silicate board first, and then a 2-cm-thick wooden plug was stacked on it (the mode of Fig. 2(f)). Various numerical values were adjusted as shown in Table 1. Hereinafter, a fire resistance test was conducted in the same manner as in Comparative Example 1.

[0060] [Judgment of Fire Resistance Test] The judgment criteria for the fire resistance test are as follows. · When the reach depth [Lt] of the screw tip is smaller than the char depth [Cs] of the screw part (Lt < Cs), it means that the charring has progressed inward from the tip of the screw, so the judgment was made as poor (× mark). · When the reach depth [Lt] of the screw tip is larger than the char depth [Cs] of the screw part (Lt > Cs), it means that the effect of embedding the screw continues to be exerted even after a fire, so the judgment was made as excellent (〇 mark). · However, even if "Lt > Cs", if the increase amount Ci of the char depth of the screw part is 5 mm or more (which means that the increase in the char depth of the screw part is obvious), it is recognized that the charring of the wood around the screw due to thermal crosslinking is large, so the judgment was made as insufficient (△ mark).

[0061] [Results] From the results shown in Table 1, it can be seen that when the fixed length [Lc] after charring is larger than the char depth [Cg] of the general part (Lc > Cg), the judgment of the fire resistance test is excellent. In Table 1, the case where Lc > Cg is indicated as "OK", and the case where it is not satisfied is indicated as "NG".

[0062] [Table 1] [Industrial Applicability]

[0063] The present invention can be used in wooden buildings. [Explanation of symbols]

[0064] 1A, 1B...fire-resistant structural material, 2...load-bearing part, 3...fire-stopping part, 3a...fire-stopping layer, 4...foam fire-resistant layer, 4a...foam fire-resistant sheet, 6...lamina, 7...fixing member, 8...wooden plug, 8a...plug, 9...bracket, B...boundary, D...carbonized part.

Claims

1. a load-bearing portion having a central portion made of wood and a substantially rectangular cross section; a flame-extinguishing portion located outside the load-bearing portion; A fire-resistant structural material comprising: an intumescent fire-resistant layer provided on the outside of the fire-stopping portion; At least the outermost part of the fire-stopping portion is made of wood, a metal fixing member extends from the fire-stopping portion toward the load-supporting portion, passing through the fire-stopping portion and reaching the inside of the load-supporting portion; A fire-resistant structural material in which, in a preliminary fire resistance test based on ISO 834, the char depth [Cg] of the charred portion of the fire-stopping portion in a location where the fixing member is not present and the length [Lc] from the boundary between the charred and uncharred portions of the fire-stopping portion to the end of the fixing member on the load-supporting portion side satisfy the following formula (1): Lc>Cg ... (1)

2. 2. The fire-resistant structural material according to claim 1, wherein the load-bearing portion and the fire-stopping portion are independent members.

3. 2. The fire-resistant structural material according to claim 1, wherein the Lc is 10 mm or more.

4. 2. The fire-resistant structural material according to claim 1, wherein the intumescent fire-resistant layer is also provided on the surface of the end of the fixing member on the side of the fire-stopping portion.

5. an end of the fixing member on the side of the fire-stopping portion is located inside the fire-stopping portion and in a portion that will be charred in the fire resistance test; 2. The fire-resistant structural material according to claim 1, further comprising a plug disposed therein to fill a step formed between the end portion and the surface of the fire-stop portion.

6. 2. The fire-resistant structural material according to claim 1, wherein the fire-stopping portion is made of wood impregnated with a fire-retardant agent.

7. 2. The fire-resistant structural material according to claim 1, which is a member constituting a pillar, a beam, a wall, or a ceiling.

8. When a fire-resistant structural material is used that has a load-bearing portion whose central portion is made of wood and whose cross section is substantially rectangular, a fire-stopping portion located outside the load-bearing portion, and an intumescent fire-resistant layer provided on the outside of the fire-stopping portion, and at least the outermost portion of the fire-stopping portion is made of wood, and a metal fixing member is applied from the fire-stopping portion side toward the load-bearing portion so as to penetrate the fire-stopping portion and reach the inside of the load-bearing portion, A method for determining the depth position of a fixing member, which determines the length of the fixing member to be applied and the depth position of the end portion on the side of the fire-stopping portion so that, in a preliminary fire resistance test based on ISO 834, the char depth [Cg] of the charred portion of the fire-stopping portion in a location where the fixing member is not present and the length [Lc] from the boundary between the charred and uncharred portions of the fire-stopping portion to the end portion of the fixing member on the side of the load-supporting portion satisfy the following formula (1): Lc>Cg ... (1)

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