JP2016014230A - Fire-resistant exterior wall structure for wooden building - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fire-resistant exterior wall structure for a wooden building having fireproof performance, easily constructed and inexpensively built.SOLUTION: A fire-resistant exterior wall structure 1 includes a structural face material 24 attached to an outdoor side of a structural member 2 constituted with wood, a furring strip material 42a attached to an outdoor side face of the structural face material 24, and a lightweight cellular concrete panel 44 attached to an outdoor side face of the furring strip material 42a. The lightweight cellular concrete panel 44 has density d of 200 kg/mor more and 550 kg/mor less, a thickness t of 45 mm or more and 100 mm or less, and an ignition loss value α of 5 wt.% or more and 15 wt.% or less, and a value of d(kg/m)×t(mm)×α(wt%)÷100000 is 4000 or more and 30000 or less.

Description

  The present invention relates to a fireproof outer wall structure of a wooden building.

  Recently, there have been many studies on wooden refractory buildings. The reasons include the promotion of further use of timber under the initiative of the country, further spread of wooden buildings, and improvement of fire resistance of buildings from the viewpoint of disaster prevention due to earthquakes in urban areas.

  In order to construct a wooden fireproof building, it is required to make the outer walls, floors, beams, columns, roofs, and stairs, which are the main structural parts of the building, have a fireproof structure. Also, wooden fireproof buildings are required to be self-supporting without collapsing after the fire has occurred and the fire has extinguished.

  In order for an outer wall of a building to be recognized as fireproof, it must pass a test that tests fireproof performance. The evaluation test method is defined in JIS-A-1304. In the test method, a test body having an outer wall structure is heated from the outdoor side or from the indoor side twice in total. The heating conditions are specified in ISO-834, and the condition is that the temperature in the furnace in which the test body is installed is raised to about 950 ° C. over 1 hour, and then the heating is stopped and left as it is for 3 hours. It is.

  As a conventional fireproof outer wall structure of a wooden building, there is a structure in which a structural member made of wood is covered with a noncombustible material so that the structural member made of wood is not carbonized or ignited when a fire occurs. In the structure, a nonflammable interior member is disposed on the indoor side of the structural member, and a nonflammable exterior member is disposed on the outdoor side. In particular, research and development has been conducted on exterior members. As a conventional fireproof outer wall structure of a wooden building, the structures described in Patent Document 1 and Patent Document 2 are known.

  Patent Document 1 discloses a first covering layer formed by pressing and joining a lightweight cellular concrete panel with an exterior exterior member of a structural member made of wood, and a second covering formed by pressing and joining a calcium silicate plate. A structure is disclosed in which the coating layer is laminated and the first coating layer is installed on the outdoor side so that the joint portion of the lightweight cellular concrete panel and the calcium silicate joint portion do not overlap each other. ing.

  Patent Document 2 discloses a structure in which the exterior member is one type of calcium silicate plate, but two types of calcium silicates having different thickness dimensions and densities are used. In this structure, three calcium silicate plates are overlapped and the joint portions of the calcium silicate plates are not overlapped.

JP 2005-299194 A JP 2011-256536 A

  As a conventional exterior member of a fire-resistant outer wall structure of a wooden building, there are a structure in which a plurality of different types of materials are laminated together and a structure in which a plurality of the same materials are laminated together. In the outer wall structure of Patent Document 1, two types of exterior members, a lightweight cellular concrete panel and a calcium silicate plate, are used, and the joint portions of the exterior member need to be shifted from each other. Moreover, in the outer wall structure of patent document 2, it was necessary to laminate | stack the calcium silicate board from which specific gravity and thickness differ as an exterior member, and to shift a joint part mutually. The reason why several kinds or a plurality of exterior members are laminated and the joint portions are shifted from each other is to improve fire resistance.

  However, when several types of exterior members are present, procurement of materials and quality control become very laborious, leading to cost increase. Moreover, the number of man-hours increases and the construction period may be prolonged by constructing a plurality of exterior members. Furthermore, since the joint portions of the exterior member had to be shifted from each other, the design and construction were complicated and the construction period tended to be long.

  Then, this invention solves the subject which such a prior art has, and aims at providing the fireproof outer wall structure of a wooden building which has fireproof performance, is easy to construct, and is low-cost. .

  In order to solve the above problems, the present invention relates to the following [1] to [5].

[1] A fire-resistant outer wall structure of a wooden building, which is a structural face member attached to the outdoor side of a structural member made of wood, and a body frame member attached to the outdoor side surface of the structural face member And a lightweight cellular concrete panel attached to the outdoor side surface of the waistband material, and the lightweight cellular concrete panel has a density d of 200 kg / m ³ or more and 550 kg / m ³ or less and a thickness t of The ignition loss value α is not less than 45 mm and not more than 100 mm, and not less than 5 wt% and not more than 15 wt%, and d (kg / m ³ ) × t ³ (mm ³ ) × α (wt%) ÷ 100,000 is 4000 It is characterized by being 30000 or less.

[2] The density d of the lightweight cellular concrete panel may be 250 kg / m ³ or more and 400 kg / m ³ or less.

  [3] A thickness t of the lightweight cellular concrete panel may be 45 mm or more and 75 mm or less.

  [4] The ignition loss value α of the lightweight cellular concrete panel may be 8 wt% or more and 13 wt% or less.

[5] The value of d (kg / m ³ ) × t ³ (mm ³ ) × α (wt%) ÷ 100,000 may be 5000 or more and 150,000 or less.

  In such a configuration, a lightweight cellular concrete panel is provided as an exterior member. Since this lightweight cellular concrete panel has the design parameters described above, sufficient panel strength is ensured, and it is possible to exhibit high fire resistance while suppressing an increase in panel weight. Since the increase in the panel weight is suppressed, the deterioration of workability and the earthquake resistance of the building is suppressed. Further, since the exterior member is a lightweight lightweight concrete panel, the work of shifting the joints from each other is not necessary. Therefore, it is possible to realize a fire-resistant outer wall structure of a wooden building that is simple in construction and low in cost.

  Here, the relationship between the design parameters of the lightweight cellular concrete and the fire resistance performance will be described in detail. In order to configure the exterior members of a fire-resistant outer wall structure of a wooden building with a single layer of lightweight cellular concrete panels, the lightweight cellular concrete panels are designed in consideration of the following three parameters that are largely related to the fire performance of lightweight cellular concrete panels. There is a need to. The three parameters are (1) the density of the lightweight cellular concrete panel, (2) the thickness of the lightweight cellular concrete panel, and (3) the amount of “water” that the lightweight cellular concrete has, that is, the lightweight cellular concrete. It is the amount of “water” that calcium silicate hydrate has.

  The present inventors have intensively studied what factors determine the fire resistance of lightweight cellular concrete panels. As a result of the study, the present inventors have found that the fire resistance performance of the lightweight cellular concrete panel is determined by the amount of “water” possessed by the lightweight cellular concrete. The “water” described here is “water” of the calcium silicate hydrate constituting the lightweight cellular concrete. In other words, it is “water” hydrated with calcium silicate. The fire resistance performance of the lightweight cellular concrete panel improves as the amount of “water” contained in the calcium silicate hydrate increases.

  Here, since the absolute amount of calcium silicate hydrate increases by increasing the density of the lightweight cellular concrete panel, the fire resistance performance is improved. On the other hand, when the density is reduced, the fire resistance is lowered. On the other hand, when the density is increased, the panel weight increases, so that the workability may decrease, or the earthquake resistance may decrease due to the increase in the building weight. Moreover, if the density is too low, the physical strength of the lightweight cellular concrete panel may be insufficient.

  Moreover, since the absolute amount of calcium silicate hydrate increases by increasing the thickness of the lightweight cellular concrete panel, the fire resistance performance is improved. On the other hand, when the thickness is reduced, the fire resistance is lowered. On the other hand, when the thickness of the lightweight cellular concrete panel increases, the workability may decrease, and the earthquake resistance may decrease due to an increase in the building weight. If the thickness is too thin, the physical strength of the lightweight cellular concrete panel may be insufficient.

  Moreover, when the amount of water contained in the lightweight cellular concrete, that is, the amount of water contained in the calcium silicate hydrate constituting the lightweight cellular concrete panel is increased, the fire resistance performance is improved. Conversely, when the amount of water contained in the calcium silicate hydrate decreases, the fire resistance performance decreases. However, it is difficult to actually quantify the water of calcium silicate hydrate in lightweight cellular concrete. Therefore, in the present invention, the amount of water contained in the lightweight cellular concrete is defined as the amount of water contained in the lightweight cellular concrete by reducing the weight of the lightweight cellular concrete by heating. This value is defined as “ignition loss value”. Therefore, it can be said that the greater the ignition loss value, the higher the fire resistance.

  As described above, it is not appropriate to design the lightweight cellular concrete panel used for the outer wall structure considering only the ignition loss value deeply related to the fire resistance performance. That is, it is necessary to consider the thickness and density of lightweight cellular concrete panels that are related to panel strength and panel weight related to seismic performance and workability.

As a result of intensive studies on the above three parameters, the present inventors have (1) a density d of 200 kg / m ³ or more and 550 kg / m ³ or less, and (2) a thickness t of 45 mm or more and 100 mm or less. (3) The ignition loss value α is 5 wt% or more and 15 t% or less, and the value of d (kg / m ³ ) × t ³ (mm ³ ) × α (wt%) ÷ 100,000 is 4000 or more and 30000 or less. In this case, it has been found that it is possible to satisfy the requirements for all of panel weight, panel strength, and fire resistance.

  ADVANTAGE OF THE INVENTION According to this invention, it has fireproof performance, construction is easy, and the fireproof outer wall structure of a low-cost wooden building can be provided.

FIG. 1 is a perspective view showing a part of a fireproof outer wall structure of a wooden building according to an embodiment of the present invention. FIG. 2 is a horizontal sectional view showing a fireproof outer wall structure of a wooden building according to an embodiment of the present invention.

  Hereinafter, a preferred embodiment of a fireproof outer wall structure of a wooden building according to the present invention will be described in detail with reference to the drawings. In addition, as this embodiment, it demonstrates using the example which applied the fireproof outer wall structure to the frame structure of the wooden frame wall construction method. FIG. 1 is a perspective view showing a part of a fireproof outer wall structure according to an embodiment of the present invention. FIG. 2 is a horizontal sectional view showing a fireproof outer wall structure according to an embodiment of the present invention.

  Here, "wooden building" is a general term for buildings in which main structural members such as pillars, beams, girders, etc. are made of wood, and the construction method of a building is a wooden frame construction method, a wooden frame construction method, etc. The construction method. “Wood” refers to a wooden material, and includes a woody material formed by processing wood fibers. The “structural member” refers to a main part that supports the load and external force of a building such as a frame member (a beam, a column, a brace, etc.) of a wooden frame structure method or a frame structure of a wooden frame wall method. The meanings of the terms “fireproof structure” and “fireproof performance” are the same as those defined in Article 2 of the Building Standard Law and Article 107 of the Building Standard Law Enforcement Order.

<Fireproof outer wall structure 1>
As FIG. 1 and FIG. 2 show, the fireproof outer wall structure 1 which concerns on this embodiment is a wall body which partitions the indoor and outdoor of a building, and the structure used for a frame wall construction method is employ | adopted. The fireproof outer wall structure 1 includes a structural member 2, an interior member 3 provided on the indoor side of the structural member 2, and an exterior member 4 provided on the outdoor side of the structural member 2.

<Structural member 2>
The structural member 2 is a member that becomes a skeleton of the wall body, and supports the load and external force of the building. The structural member 2 includes a plurality of vertical frame members 21, an upper frame member 22 that connects the upper ends of the plurality of vertical frame members 21, and a lower frame member 23 that connects the lower ends of the plurality of vertical frame members 21. And have. A structural face member 24 is attached to the frame member 21 on the surface of the structural member 2 on the outdoor side.

  The vertical frame member 21, the upper frame member 22, and the lower frame member 23 are long wooden members each having a cross-sectional dimension of, for example, 38 mm × 89 mm, which are known as wood for a frame wall construction method, such as nails or screws. Are fastened together. The vertical frame material 21 is erected at equal intervals with a horizontal interval of 455 mm or less.

  The structural face material 24 is fixed by nailing to a frame composed of the vertical frame material 21, the upper frame material 22, and the lower frame material 23, and constitutes an outdoor-side surface. In this manner, the vertical frame member 21, the upper frame member 22, the lower frame member 23, and the structural face member 24 are integrated, thereby exhibiting performance as the structural member 2.

As the structural face material 24, for example, a structural plywood conforming to Japanese Agricultural Standards having a thickness of 9 mm and a density of 0.55 g / cm ³ can be used. Further, as the structural face material 24, for example, a structural board having a thickness of 9 mm or more, a structural panel having a thickness of 9 mm or more, a particle board having a thickness of 9 mm or more, or a sieving board having a thickness of 12 mm or more. And a hard wood chip cement board with a thickness of 12 mm to 25 mm, a pulp cement board with a thickness of 9 mm or more, a flexible board with a thickness of 9 mm or more, a calcium silicate board with a thickness of 9 mm or more, a thickness of 9 mm or more A volcanic glassy multilayer board, a gypsum board having a thickness of 12 mm or more, and the like can be used.

<Insulation 25>
Since the architectural style of the refractory outer wall structure 1 is a wooden frame wall construction method, it is preferable from the viewpoint of improving heat insulation performance that the heat insulating material 25 is filled between the adjacent frame materials 21. As the heat insulating material 25, for example, glass wool having a density of 24 kg / m ³ or rock wool can be used. In addition, when the architectural style of the fireproof outer wall structure 1 is a wooden frame construction method, a heat insulating material may be filled between the columns and the intercolumns and between the intercolumns and the intercolumns.

<Interior member 3>
The interior member 3 constitutes a wall surface on the indoor side of the wall body, and protects the structural member 2 from a flame such as a fire generated indoors. The interior member 3 includes an interior underlayer 31 made of reinforced gypsum board attached to the indoor side of the structural member 2 and an interior overcoat layer 32 made of reinforced gypsum board laminated on the indoor side of the interior underlayer 31. doing.

  The interior underlayer 31 is configured by abutting and joining the small edge surfaces of a plurality of reinforced gypsum boards to each other. The interior underlayer 31 is fixed to the structural member 2 with a gypsum board nail.

  The interior overlying layer 32 is configured by butting and joining the small edge surfaces of a plurality of reinforced gypsum boards. The interior upper layer 32 penetrates the interior underlayer 31 and is fixed to the structural member 2 with a plaster board nail.

  These reinforced gypsum boards preferably have a thickness of 21 mm or more and a bulk specific gravity of 0.75 or more. According to such a reinforced gypsum board, the water in the reinforced gypsum board is vaporized by the heat of the fire when a fire occurs indoors, so it is possible to consume the heat of the fire and delay the transfer of heat. . Therefore, carbonization and ignition of the structural member 2 can be prevented, and fire resistance against heat from the indoor side can be ensured. The interior member 3 may have an aluminum foil that is sandwiched between the interior underlayer 31 and the interior overlayer 32.

<Exterior member 4>
The exterior member 4 constitutes a wall surface on the outdoor side of the wall body, and protects the structural member 2 from flames such as a fire that occurs outdoors. The exterior member 4 includes a waterproof layer 41 formed on the outdoor side surface of the structural member 2, a ventilation layer 42 (see FIG. 2) formed on the outdoor side surface of the waterproof layer 41, and the outdoor side of the ventilation layer 42. A lightweight cellular concrete panel layer 43 disposed on the wall.

  The waterproof layer 41 protects the structural member 2 from rainwater or the like that has penetrated from the gaps in the exterior member 4 and is attached to the surface on the outdoor side of the structural face material 24 with an adhesive, tape, staple, or the like. As the waterproof layer 41, it is preferable to use an asphalt felt according to JIS-A-6006 or a moisture-permeable waterproof sheet according to JIS-A-6111.

  The ventilation layer 42 allows air to flow in the vertical direction and prevents corrosion of the structural member 2 due to moisture. The ventilation layer 42 is configured by installing a plurality of trunk edges 42a at predetermined intervals in the horizontal direction on the outdoor side of the waterproof layer 41. A space that communicates from the lower end portion of the exterior member 4 to the upper end portion is formed between the waterproof layer 41 and the lightweight cellular concrete panel layer 43 and between the adjacent trunk edge materials 42a. . The trunk edge member 42a is an elongated thin plate-like member having a cross-sectional dimension of 18 mm × 90 mm made of, for example, a surplus material. The trunk edge member 42a is fixed to the structural member 2 with nails, screws, or the like.

  The lightweight cellular concrete panel layer 43 is formed by pressing and joining a plurality of lightweight cellular concrete panels 44 to the outdoor side surface of the trunk edge material 42a.

  The lightweight cellular concrete panel 44 is a panel molded into a plate shape and has excellent characteristics such as light weight, high heat insulation, high workability, and high fire resistance. Therefore, lightweight cellular concrete panels are used in many buildings in a wide range of fields, from high-rise buildings to ordinary houses. For example, lightweight cellular concrete panels are used in parts such as outer walls, partitions, floors, and roofs. In the lightweight cellular concrete panel, a slurry obtained by mixing a siliceous raw material, a calcareous raw material, water, a foaming agent, and the like is poured into a mold to foam the mixture. Subsequently, the semi-cured mixture is obtained by curing at high temperature and high pressure steam in an autoclave.

The lightweight cellular concrete panel 44 is a plate-like panel. The lightweight cellular concrete panel 44 is fixed to the structural member 2 by screwing or the like. The lightweight cellular concrete panel 44 has a density d of 200 kg / m ³ or more and 550 kg / m ³ or less, a thickness t of 45 mm or more and 100 mm or less, and an ignition loss value α of 5 wt% or more and 15 wt%. It is as follows. The value of density d (kg / m ³ ) × thickness t ³ (mm ³ ) × ignition loss value α (wt%) ÷ 100,000 is 4000 or more and 30000 or less. According to the lightweight cellular concrete panel 44 satisfying such parameters, the structural member 2 can be prevented from being carbonized or ignited against a fire from the outside.

  The lightweight cellular concrete panel 44 preferably has a reinforcing reinforcing bar and a reinforcing wire mesh embedded therein. Here, the reinforcing reinforcing bars are obtained by arranging reinforcing bars in a desired shape and welding the crossing contacts. Further, the reinforcing wire mesh is obtained by processing iron into a net shape, and a lath net or the like is a typical example. The shape, size, thickness of the reinforcing bar, size of the mesh of the reinforcing mesh, etc. are not limited. These reinforcing reinforcing bars or reinforcing wire meshes are preferably subjected to a rust preventive treatment effective for durability. As the rust preventive material, a known synthetic resin material or the like can be used.

  As the density d of the lightweight cellular concrete panel 44 is larger, the absolute amount of calcium silicate hydrate constituting the lightweight cellular concrete is increased, and the fire resistance performance is improved. However, as the density d of the lightweight cellular concrete panel 44 increases, the panel weight increases. According to the increase in the panel weight, the workability is reduced, the building weight is increased, the seismic performance is reduced, and the raw material for manufacturing the lightweight cellular concrete panel 44 is increased, so that the manufacturing cost is increased. Cases can arise.

  On the other hand, the lower the density d of the lightweight cellular concrete panel 44, the lighter the panel weight. Therefore, there are advantages that workability is improved, earthquake resistance is improved by reducing the weight of the building, and raw materials for manufacturing the lightweight cellular concrete panel 44 are reduced, thereby reducing manufacturing costs. However, as the density d of the lightweight cellular concrete panel 44 is lower, the absolute amount of calcium silicate is reduced, so that the fire resistance may be lowered or the panel strength may be lowered.

Therefore, as a result of intensive studies, the present inventors have found that the range of the density d of the lightweight cellular concrete panel 44 is 200 kg / m ³ or more and 550 kg / m ³ or less, preferably 230 kg / m ³ or more and 500 kg / m ^3. It has been found that it is not less than 250 kg / m ³ and more preferably not more than 400 kg / m ³ . Here, when the density d is less than 200 kg / m ³ , the panel strength is low and the fire resistance is low, which is not practical. On the other hand, when the density d exceeds 550 kg / m ³ , the panel weight is heavy, so that the workability is reduced and the building weight is increased and the seismic performance is lowered, which is not practical.

  Further, as the thickness t of the lightweight cellular concrete panel 44 is increased, the absolute amount of calcium silicate hydrate constituting the lightweight cellular concrete panel 44 is increased, and the fire resistance is improved. However, the greater the thickness t of the lightweight cellular concrete panel 44, the greater the panel weight. According to the increase in the panel weight, the workability is reduced, the building weight is increased, the seismic performance is reduced, and the raw material for manufacturing the lightweight cellular concrete panel 44 is increased, so that the manufacturing cost is increased. Cases can arise.

  On the other hand, the smaller the thickness t of the lightweight cellular concrete panel 44, the lighter the panel weight. According to the weight reduction of the panel weight, the workability is improved, the building weight is lightened, the earthquake resistance is improved, and the raw material for producing the lightweight cellular concrete panel 44 is reduced, so that the manufacturing cost is reduced. There are benefits. However, there may be a case where the fire resistance performance decreases due to a decrease in the absolute amount of calcium silicate hydrate.

  Therefore, as a result of intensive studies, the present inventors have found that the range of the thickness t of the lightweight cellular concrete panel 44 is 45 mm to 100 mm, preferably 45 mm to 80 mm, more preferably 45 mm to 75 mm. I found out. Here, when the thickness t is less than 45 mm, the fire resistance is low, which is not practical. On the other hand, when the thickness t exceeds 100 mm, the workability deteriorates and is not practical.

  Further, as the ignition loss value α of the lightweight cellular concrete panel 44 is larger, the fire resistance performance of the lightweight cellular concrete panel 44 is higher. That is, when the ignition loss value α is large, the amount of water that the lightweight cellular concrete panel 44 has, that is, the “water” that the calcium silicate hydrate constituting the lightweight cellular concrete has is large in the lightweight cellular concrete. It is because it is doing. However, the production of lightweight cellular concrete panels 44 containing a large amount of calcium silicate hydrate is technically difficult, so there is an upper limit to the amount of calcium silicate hydrate that can be present in lightweight cellular concrete. On the other hand, the smaller the ignition loss value α, the lower the fire resistance performance of the lightweight cellular concrete panel 44.

  Accordingly, as a result of intensive studies, the inventors have determined that the range of the ignition loss value α of the lightweight cellular concrete panel 44 is 5 wt% or more and 15 wt% or less, preferably 7 wt% or more and 14 wt% or less, more preferably 8 wt%. % To 13 wt%. Here, when the ignition loss value α is less than 5 wt%, the fire resistance is low, so the fire resistance required for the fire resistant outer wall structure 1 cannot be satisfied.

However, in order to satisfy all of the panel weight, panel strength, and fire resistance required for the lightweight cellular concrete panel 44, the lightweight cellular concrete panel 44 has the above three parameters: (1) density d (kg / M ³ ), (2) thickness t (mm), and (3) ignition loss value α (wt%) may be insufficient even in the above numerical range.

  For example, even if the density d, the thickness t, and the ignition loss value α are within the above numerical range, the lightweight cellular concrete having the density d and the thickness t close to the upper limit of the numerical range. The panel 44 satisfies the fire resistance performance, but the panel weight increases, so that the workability is lowered and may not be practical.

  Moreover, although the density d is in the above numerical range, the lightweight cellular concrete panel 44 in which the density d is close to the lower limit of the numerical range may not satisfy the fire resistance. In that case, it is necessary to increase the thickness t of the lightweight cellular concrete panel 44 or the ignition loss value α.

Accordingly, in order to satisfy all of the panel weight, panel strength, and fire resistance required for the lightweight cellular concrete panel 44, the lightweight cellular concrete panel 44 needs to comprehensively evaluate the above three parameters. . As a result of intensive studies on the evaluation method, the present inventors have conducted a new study of density d (kg / m ³ ) × (thickness t) ³ (mm ³ ) × ignition loss value α (wt%) ÷ 100,000. We found that it can be evaluated by parameters.

The value of density d (kg / m3) × (thickness t) ³ (mm ³ ) × ignition loss value α (wt%) ÷ 100,000, which is a new parameter, is not less than 4000 and not more than 30000, preferably 4500 It has been found that the panel weight, the panel strength, and the fire resistance can be suitably satisfied when the value is 25000 or less and more preferably 5000 or more and 15000 or less.

  According to the fireproof outer wall structure 1 including the lightweight cellular concrete panel 44, it is possible to satisfy the panel weight, the panel strength, and the fireproof performance required for the lightweight cellular concrete panel 44 in a balanced manner. Therefore, the exterior member 4 can be composed of only one kind of material and a single exterior member, that is, a lightweight cellular concrete panel 44. For this reason, construction is simple and low-cost fireproof outer wall structure 1 is realizable. For example, according to the fireproof outer wall structure 1, heating is performed for 1 hour under the heating conditions specified by ISO-834 from the outdoor side or indoor side, and after the heating is stopped, the structural member is carbonized. It has been confirmed that no ignition is observed. And according to the fireproof outer wall structure 1, it becomes possible to construct | assemble a wooden fireproof building easily, and the greater spread of wooden construction can be aimed at.

  The fireproof outer wall structure 1 includes an interior underlayer 31 made of reinforced gypsum board on the indoor side of the structural member 2 made of wood, and an interior overcoat layer made of reinforced gypsum board on the indoor side of the interior underlayer 31. 32 is laminated. According to this two-layer structure, the heat of the fire transmitted to the structural member 2 made of wood can be reduced and the carbonization and ignition of the structural member 2 can be prevented against an indoor fire.

  Next, the Example at the time of performing a fireproof performance evaluation test using the fireproof outer wall structure 1 shown by FIG. 1, FIG. 2 is described. In addition, this invention is not limited to the specific dimension illustrated by a following example.

  First, the fireproof outer wall structure 1 will be described in detail. The structure is comprised from the structural member 2, the interior member 3, and the exterior member 4, and the structure used for the wooden frame wall construction method is employ | adopted.

<Structural member 2>
The structural member 2 includes a plurality of vertical frame members 21, an upper frame member 22 that connects the upper ends of the plurality of vertical frame members 21, and a lower frame member 23 that connects the lower ends of the plurality of vertical frame members 21. It is comprised from the structural surface material attached to the surface of the outdoor side of a vertical frame. The vertical frame member 21, the upper frame member 22, and the lower frame member 23 are long wooden members each having a cross-sectional dimension of 38 mm × 89 mm used as wood for the frame wall construction method. The vertical frame member 21, the upper frame member 22, and the lower frame member 23 were fastened to each other with screws. The vertical frame material 21 was erected at equal intervals of 455 mm. The structural face material 24 was a structural plywood having a thickness of 9 mm. The structural face material 24 was fixed to the vertical frame material 21, the upper frame material 22, and the lower frame material 23 by hitting nails on the outdoor side surface of the vertical frame. In addition, glass wool having a density of 24 kg / m ³ was filled as the heat insulating material 25 between the adjacent vertical frame members 21.

<Interior member 3>
The interior member 3 has a reinforcing gypsum board having a thickness of 21 mm as an interior underlayer 31 on the surface of the structural member 2 on the indoor side, and a thickness of 21 mm as an interior upper layer 32 on the interior side of the interior underlayer 31. The reinforced gypsum board was laminated with a two-layer structure. The interior underlayer 31 is configured by abutting and joining a plurality of reinforced gypsum boards to each other. The structural member 2 was struck with nails for plasterboard. The interior overlying layer 32 is configured by abutting and joining a plurality of reinforced gypsum boards to each other. The interior upper layer 32 penetrated the interior underlayer 31 with nails and was applied to the structural member 2. Further, a joint treatment agent for gypsum board according to JIS-A-6914 was applied to the joint portion of the interior overlying layer 32 as a joint treatment agent for interior material to finish it smoothly.

<Exterior member 4>
The exterior member 4 includes a waterproof layer 41 on the outdoor side of the structural face material 24, a ventilation layer 42 on the outdoor side surface of the waterproof layer 41, and a lightweight cellular concrete panel layer 43 on the outdoor side surface of the trunk edge material 42 a. Has been. The waterproof layer 41 is a moisture permeable waterproof sheet (manufacturer: Asahi, Deyupon, Flash, Span Product Co., Ltd., trade name: Tyvek), and was affixed to the outdoor side surface of the structural face material 24 using staples. The seam of the moisture permeable waterproof sheet was overlapped at 90 mm both vertically and horizontally. The ventilation layer 42 is configured by placing a plurality of trunk edge members 42a on the outdoor side of the waterproof layer 41 with a predetermined interval in the horizontal direction and hitting the structural face material 24 using nails. The trunk edge member 42a is an elongated thin plate-like member having a cross-sectional dimension of 18 mm × 90 mm made of a surplus material. The lightweight cellular concrete panel layer 43 was formed by abutting and joining a plurality of lightweight cellular concrete panels 44 to the outdoor side surface of the trunk edge material 42a. The lightweight cellular concrete panel 44 was fixed to the structural member 2 with screws. An acrylic sealing material was applied to the joints of the lightweight cellular concrete panel layer 43.

  The fire-resistant outer wall structure 1 of the present example was constituted by the structural member 2, the interior member 3, and the exterior member 4.

  Next, a method for measuring each value of the lightweight cellular concrete panel 44 and a fire resistance evaluation test method for the fire resistant outer wall structure will be described.

<Density of lightweight cellular concrete panel>
A block having a size of 100 (mm) × 100 (mm) × 40 (mm) was cut out from the lightweight cellular concrete panel, and the block was dried to a constant weight with a dryer at 105 ° C. The weight W (kg) after the drying and the volume V (m ³ ) of the block were measured and calculated by the formula (1).
Density d (kg / m ³ ) = W / V (1)

<Thickness t of lightweight cellular concrete panel>
The thickness t of the lightweight cellular concrete panel was measured to the unit of 1 mm with a caliper.

<Light loss value α of lightweight cellular concrete panel>
The lightweight cellular concrete was pulverized until it became powdery. The powder was dried with a dryer at 105 ° C. until a constant weight was reached. The weight after drying was defined as A (g). Next, the powder which became the constant weight was heated for 1 hour using the electric furnace of 1000 degreeC. The weight after heating was measured, and the weight was defined as B (g). The ignition loss value α was calculated by the equation (2).
Ignition loss value α (wt%) = (A−B) × 100 / B (2)

<Moisture content β of lightweight cellular concrete panel>
A block having a size of 600 (mm) × 600 (mm) × 40 (mm) was cut out from the lightweight cellular concrete panel, and the weight C (kg) of the block was measured. The block was dried with a dryer at 105 ° C. until a constant weight was reached. The dried weight D (kg) is measured. The moisture content β of the lightweight cellular concrete panel was calculated by the formula (3).
Moisture content β (wt%) = (C−D) × 100 / D (3)

<Evaluation method of fireproof performance of fireproof outer wall structure>
A specimen having a fire-resistant outer wall structure was heated from the outdoors or indoors for 1 hour according to the heating curve defined in ISO-834, and then the heating was stopped and left as it was for 3 hours. Thereafter, the test body was disassembled, and the structural member 2 was visually inspected for carbonization and ignition. Further, when heating from the outside, a thermocouple was attached to the surface of the structural face material 24 on the outdoor side, and the temperature was measured every minute using a data logger. The highest temperature measured at that time is referred to as “the highest temperature of the structural face material 24”.

Example 1
In Example 1, fire resistance performance evaluation of the fire resistant outer wall structure 1 comprised of the structural member 2, the interior member 3, and the exterior member 4 was performed. The density d, thickness t, and ignition loss value α of the lightweight cellular concrete panel 44 are as follows.
Density d = 375 (kg / m ³ )
Thickness t = 50 (mm)
Ignition loss value α = 11.5 (wt%)
Density d × (thickness t) ³ × ignition loss value α ÷ 100,000 = 5391
Moisture content β = 2.6 (wt%)

(Fire resistance evaluation result of Example 1)
Indoor heating: No carbonization or ignition was observed in the structural member 2.
Heating from outside: The structural member 2 was not carbonized or ignited.
The maximum temperature of the structural face material 24 was 245 ° C.

(Example 2)
In Example 2, fire resistance performance evaluation of the fire resistant outer wall structure 1 constituted by the structural member 2, the interior member 3, and the exterior member 4 was performed. The density d, thickness t, and ignition loss value α of the lightweight cellular concrete panel 44 are as follows.
Density d = 490 (kg / m ³ )
Thickness t = 50 (mm)
Ignition loss value α = 8.1 (wt%)
Density d × (thickness t) ³ × ignition loss value α ÷ 100,000 = 4961
Moisture content β = 2.8 (wt%)

(Fire resistance evaluation result of Example 2)
Indoor heating: No carbonization or ignition was observed in the structural member 2. Heating from outside: The structural member 2 was not carbonized or ignited. The maximum temperature of the structural face material 24 was 240 ° C.

(Example 3)
In Example 3, fire resistance performance evaluation of the fire resistant outer wall structure 1 constituted by the structural member 2, the interior member 3, and the exterior member 4 was performed. The density d, thickness t, and ignition loss value α of the lightweight cellular concrete panel 44 are as follows.
Density d = 275 (kg / m ³ )
Thickness t = 75 (mm)
Ignition loss value α = 11.4 (wt%)
Density d × (thickness t) ³ × ignition loss value α ÷ 100,000 = 13226
Moisture content β = 2.9 (wt%)

(Fire resistance evaluation result of Example 3)
Indoor heating: No carbonization or ignition was observed in the structural member 2. Heating from outside: The structural member 2 was not carbonized or ignited. The maximum temperature of the structural face material 24 was 120 ° C.

Example 4
In Example 4, the fireproof performance evaluation of the fireproof outer wall structure 1 composed of the structural member 2, the interior member 3, and the exterior member 4 was performed. The density d, thickness t, and ignition loss value α of the lightweight cellular concrete panel 44 are as follows.
Density d = 510 (kg / m ³ )
Thickness t = 50 (mm)
Ignition loss value α = 11.8 (wt%)
Density d × (thickness t) ³ × ignition loss value α ÷ 100,000 = 7526
Moisture content β = 2.9 (wt%)

(Fire resistance evaluation result of Example 4)
Indoor heating: No carbonization or ignition was observed in the structural member 2. Heating from outside: The structural member 2 was not carbonized or ignited. The maximum temperature of the structural face material 24 was 220 ° C.

(Comparative Example 1)
In Comparative Example 1, fire resistance performance evaluation of the fire resistant outer wall structure 1 constituted by the structural member 2, the interior member 3, and the exterior member 4 was performed. The density d, thickness t, and ignition loss value α of the lightweight cellular concrete panel 44 are as follows.
Density d = 350 (kg / m ³ )
Thickness t = 50 (mm)
Ignition loss value α = 8.3 (wt%)
Density d × (thickness t) ³ × ignition loss value α ÷ 100,000 = 3631
Moisture content β = 3.0 (wt%)

(Results of fire resistance evaluation of Comparative Example 1)
Indoor heating: No carbonization or ignition was observed in the structural member 2. Heating from outside: Carbonization was observed in the structural member 2. Moreover, since the structural member 2 ignited, the test was interrupted.

(Comparative Example 2)
In Comparative Example 2, fire resistance performance evaluation of the fire resistant outer wall structure 1 composed of the structural member 2, the interior member 3, and the exterior member 4 was performed. The density d, thickness t, and ignition loss value α of the lightweight cellular concrete panel 44 are as follows.
Density d = 490 (kg / m ³ )
Thickness t = 37 (mm)
Ignition loss value α = 8.8 (wt%)
Density d × (thickness t) ³ × ignition loss value α ÷ 100000 = 2184
Moisture content β = 3.1 (wt%)

(Fire resistance evaluation result of Comparative Example 2)
Indoor heating: No carbonization or ignition was observed in the structural member 2.
Heating from outside: Carbonization was observed in the structural member 2. Moreover, since the structural member 2 ignited, the test was interrupted.

(Comparative Example 3)
In Comparative Example 3, the fire resistance performance of the fire resistant outer wall structure 1 constituted by the structural member 2, the interior member 3, and the exterior member 4 was evaluated. The density d, thickness t, and ignition loss value α of the lightweight cellular concrete panel 44 are as follows.
Density d = 375 (kg / m ³ )
Thickness t = 37 (mm)
Ignition loss value α = 11.7 (wt%)
Density d × (thickness t) ³ × ignition loss value α ÷ 100,000 = 2222
Moisture content β = 2.6 (wt%)

(Fire resistance evaluation result of Comparative Example 3)
Indoor heating: No carbonization or ignition was observed in the structural member 2.
Heating from outside: Carbonization was observed in the structural member 2. Moreover, since the structural member 2 ignited, the test was interrupted.

  As shown in Examples 1 to 4, as a result of heating from the indoor side and the outdoor side, the structural member 2 was not carbonized or ignited, so the fire-resistant outer wall structure 1 is a “fire-resistant structure”. I understood.

In order to achieve a fire-resistant outer wall structure of a wooden building with a simple construction, low cost, only one type of exterior member, and a fire-resistant structure with only one exterior member, as a result of intensive studies, the exterior member The conclusion is that it is a lightweight cellular concrete panel. The fireproof outer wall structure includes a structural face member attached to an outdoor side of a structural member made of wood, a trunk edge member attached to an outdoor side surface of the structural face member, and A lightweight cellular concrete panel 44 is configured as an exterior member on the outdoor side surface, and the density d of the lightweight cellular concrete panel is 200 kg / m ³ or more and 550 kg / m ³ or less, and the thickness t is 45 mm or more and 100 mm or less. And the ignition loss value α is 5 wt% or more and 15 wt% or less, and the value of d (kg / m ³ ) × t ³ (mm ³ ) × α (wt%) ÷ 100,000 is 4000 or more and 30000 or less. is there.

  As mentioned above, although one Example form of this invention was described, this invention is not limited to the said embodiment. For example, although this embodiment demonstrated as an example the case where this invention was applied to the wall body used for a wooden frame wall construction method, you may apply to other wall bodies, such as a wooden frame construction method.

  According to the present invention, the exterior member can be composed of only one type of material and a single exterior member, that is, the lightweight cellular concrete panel 44, and the fire-resistant outer wall structure of a low-cost wooden building that is easy to construct. Can be provided. Therefore, it becomes possible to construct a wooden fireproof building easily, and the wooden construction can be more widely spread.

DESCRIPTION OF SYMBOLS 1 ... Fireproof outer wall structure, 2 ... Structural member, 3 ... Interior member, 4 ... Exterior member, 21 ... Frame material, 22 ... Upper frame material, 23 ... Lower frame material, 24 ... Structural surface material, 25 ... Thermal insulation material, DESCRIPTION OF SYMBOLS 31 ... Interior undercoat layer, 32 ... Interior overcoat layer, 41 ... Waterproofing layer, 42 ... Breathable layer, 42a ... Body edge material, 43 ... Lightweight cellular concrete panel layer, 44 ... Lightweight cellular concrete panel, D ... Weight, d ... density, t ... thickness, V ... volume, W ... weight, α ... ignition loss value, β ... moisture content.

Claims (5)

A fireproof outer wall structure of a wooden building,
A structural face material attached to the outdoor side of a structural member made of wood;
A torso material attached to the outdoor side surface of the structural face material;
A lightweight cellular concrete panel attached to the outdoor side surface of the waistband;
With
The lightweight cellular concrete panel has a density d of 200 kg / m ³ or more and 550 kg / m ³ or less, a thickness t of 45 mm or more and 100 mm or less, and an ignition loss value α of 5 wt% or more and 15 wt% or less. and ^{d (kg / m 3) ×} t 3 (mm 3) × α wherein the value of (wt%) ÷ 100000 is 4000 to 30,000, refractory outer wall structure of the wooden buildings. 2. The fireproof outer wall structure of a wooden building according to claim 1, wherein a density d of the lightweight cellular concrete panel is 250 kg / m ³ or more and 400 kg / m ³ or less.   The fireproof outer wall structure of a wooden building according to claim 1 or 2, wherein a thickness t of the lightweight cellular concrete panel is 45 mm or more and 75 mm or less.   The fire-resistant outer wall structure of a wooden building according to any one of claims 1 to 3, wherein an ignition loss value α of the lightweight cellular concrete panel is 8 wt% or more and 13 wt% or less. The value of d (kg / m3) × t ³ (mm ³ ) × α (wt%) ÷ 100,000 is 5000 or more and 15000 or less, according to any one of claims 1 to 4, Fireproof outer wall structure of a wooden building.

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