JP7561564B2

JP7561564B2 - Wood fireproof beam

Info

Publication number: JP7561564B2
Application number: JP2020171745A
Authority: JP
Inventors: 直人松岡; 誠治金森; 朗彦三宅
Original assignee: Kumagai Gumi Co Ltd
Current assignee: Kumagai Gumi Co Ltd
Priority date: 2020-10-12
Filing date: 2020-10-12
Publication date: 2024-10-04
Anticipated expiration: 2040-10-12
Also published as: JP2022063463A

Description

本発明は、木質梁と木質梁の側面と下面とを覆うように設けられた耐火被覆層とを備えた木質耐火梁に関する。 The present invention relates to a fire-resistant wooden beam that includes a wooden beam and a fire-resistant coating layer that is arranged to cover the sides and underside of the wooden beam.

従来、木質耐火梁として、荷重支持部としての木質梁と、木質梁の横断面のうち三方をその全長に亘って被覆する燃え代層と、木質梁と燃え代層との間に層状に介在された少なくとも１層の耐火被覆層としての燃え止まり層とを有した構成の木質耐火梁が知られている（特許文献１等参照）。
即ち、図４に示すように、荷重を支持する荷重支持部としての断面四角形状の木質梁２と、当該木質梁２の両方の側面２１，２１と下面２２とを覆うように設けられた耐火被覆層３とを備えた木質耐火梁１００が知られている。
尚、図４では、耐火被覆層３が、例えばせっこうボード等の板状の耐火被覆材３０の１枚分の厚さの１層の耐火被覆層により構成された例を示している。この場合、例えばせっこうボードは、当該せっこうボードの貼付面の全面に図外の接着剤が塗布されて当該貼付面が木質梁２の側面２１や下面２２に押し付けられた状態とされ、さらに、留付材６０としての例えばステープルが当該せっこうボードを貫通して木質梁２に打ち込まれることにより、木質梁２の両方の側面２１，２１と下面２２とを覆うようにせっこうボードが木質梁２に取付けられて１層の耐火被覆層３が構成される。また、木質梁２の上面２３には、床１０が構築される。 Conventionally, a known wooden fire-resistant beam has a structure including a wooden beam as a load-bearing portion, a substitute fire layer covering three sides of the cross section of the wooden beam over its entire length, and at least one fire-retardant layer as a fire-resistant coating layer interposed in a layered manner between the wooden beam and the substitute fire layer (see Patent Document 1, etc.).
That is, as shown in Figure 4, a wooden fire-resistant beam 100 is known which has a wooden beam 2 with a square cross-section as a load-bearing part that supports a load, and a fire-resistant coating layer 3 arranged to cover both side surfaces 21, 21 and a bottom surface 22 of the wooden beam 2.
4 shows an example in which the fireproof coating layer 3 is formed of one layer of fireproof coating layer having a thickness equivalent to that of one sheet of plate-shaped fireproof coating material 30 such as gypsum board. In this case, for example, an adhesive (not shown) is applied to the entire attachment surface of the gypsum board, and the attachment surface is pressed against the side surface 21 and the bottom surface 22 of the wooden beam 2. Furthermore, a fastening material 60, for example, a staple, is driven into the wooden beam 2 through the gypsum board, thereby attaching the gypsum board to the wooden beam 2 so as to cover both side surfaces 21, 21 and the bottom surface 22 of the wooden beam 2, thereby forming one layer of fireproof coating layer 3. A floor 10 is constructed on the top surface 23 of the wooden beam 2.

特開２０２０－６６８５０号公報JP 2020-66850 A

しかしながら、木質梁に荷重が加わった場合に、梁の梁端を支持点として梁の中央側が下方に湾曲するように撓む変形（即ち、梁特有のひずみ曲線変形）及び木質梁の下面を覆うように設けられた耐火被覆層を形成する耐火被覆材の自重の影響により、木質梁の下面を覆うように設けられた耐火被覆層が火災時などに早期に落下しやすくなる可能性があった。火災時などに当該耐火被覆層が早期に落下した場合、木質梁の表面が早期に高温に至りやすくなり、所期の耐火性能を十分に発揮できない木質耐火梁となってしまう。
特に、耐火時間を長くする場合、耐火被覆層として、例えば多数枚のせっこうボード等の耐火被覆材を積層した耐火被覆層が設けられるため、当該耐火被覆層の自重の影響がより大きくなって、木質梁の下面を覆うように設けられた耐火被覆層が火災時などにさらに早期に落下しやすくなる。
即ち、従来の木質耐火梁は、木質梁の下面を覆うように設けられた耐火被覆層が火災時などに早期に落下しやすくなり、所期の耐火性能を発揮できない木質耐火梁となってしまうという課題があった。
本発明は、上述した課題に鑑み、木質梁の下面を覆うように設けられた耐火被覆層の落下を抑制できて所期の耐火性能を発揮できるようにした木質耐火梁を提供するものである。 However, when a load is applied to a wooden beam, the beam end is supported by the center of the beam, and the center of the beam bends downward (i.e., a strain curve deformation specific to beams) and the weight of the fire-resistant coating material that forms the fire-resistant coating layer that covers the underside of the wooden beam may cause the fire-resistant coating layer that covers the underside of the wooden beam to easily fall off early in the event of a fire, etc. If the fire-resistant coating layer falls off early in the event of a fire, the surface of the wooden beam may easily reach high temperatures early, resulting in a fire-resistant wooden beam that cannot fully exhibit the desired fire resistance.
In particular, when the fire resistance time is to be extended, a fire-resistant coating layer formed by laminating a large number of fire-resistant coating materials such as gypsum boards is provided as the fire-resistant coating layer. This increases the effect of the fire-resistant coating layer's own weight, making the fire-resistant coating layer provided to cover the underside of the wooden beam more likely to fall off in the event of a fire.
In other words, conventional wooden fire-resistant beams had the problem that the fire-resistant coating layer applied to cover the underside of the wooden beam was prone to falling off early in the event of a fire, resulting in a wooden fire-resistant beam that was unable to exhibit the desired fire resistance performance.
In view of the above-mentioned problems, the present invention provides a wooden fire-resistant beam that can prevent the fire-resistant coating layer provided to cover the underside of the wooden beam from falling off, thereby enabling the desired fire-resistant performance to be exhibited.

本発明に係る木質耐火梁は、木質梁と、当該木質梁の両方の側面と下面とを覆うように設けられた耐火被覆層とを備えた木質耐火梁において、木質梁の下面を覆うように設けられた耐火被覆層の落下を抑制する吊手段を備え、吊手段は、木質梁の両方の側面に設けられた耐火被覆層を形成する耐火被覆材の外側の面及び木質梁の下面に設けられた耐火被覆層を形成する耐火被覆材の外側の面に亘って連続するように設けられたメッシュシートと、メッシュシートを耐火被覆層を形成する耐火被覆材の外側の面に固定する固定手段とを備え、耐火被覆層は、板状の耐火被覆材を２層以上に積層して構成された耐火被覆層により形成され、メッシュシートは、耐火被覆層の最外層以外のいずれか任意の層を形成する耐火被覆材の外側の面に沿って設けられ、固定手段は、接着剤及び留付材であり、接着剤は、メッシュシートのメッシュの開口を介して、メッシュシートと耐火被覆層の外側の面との間、及び、メッシュシートの外側に行き渡るように塗布され、留付材は、所定の間隔を隔てて平行に設けられた一対の針部と、一対の針部の一端同士を連結する針頭部とを備えたステープルであり、ステープルは、一対の針部間の所定の間隔が、メッシュシートのメッシュの目開きの寸法よりも大きいことを特徴とするので、木質梁の下面を覆うように設けられた耐火被覆層が、吊手段によって吊られた状態となるので、木質梁の下面を覆うように設けられた耐火被覆層の落下を抑制できて所期の耐火性能を発揮できる木質耐火梁を提供できるようになった。また、耐火被覆層が複数層の耐火被覆層であっても、木質梁の下面を覆うように設けられた耐火被覆層の落下を抑制できて所期の耐火性能を発揮できる木質耐火梁を提供できるようになった。また、取扱性、施工性に優れた木質耐火梁を提供できる。また、メッシュシートと接着剤とが一体化された状態で耐火被覆層の外側の面に接着されることになるため、メッシュシートが耐火被覆層の外側の面に強固に接着されて固定された状態となるとともに、ステープルの針頭部が、必ず、メッシュシートの線材を耐火被覆材の外側の面に押し付けて固定できるようになるため、メッシュシートが耐火被覆材の外側の面に強固に固定された状態となり、メッシュシートによる吊支持力が維持されるので、木質梁の下面を覆うように設けられた耐火被覆層の落下抑制効果が向上する。
また、木質梁に貫入されて固定されるステープルは、１層目の耐火被覆材を木質梁に取付けるステープル及び２層目の耐火被覆材を木質梁に取付けるステープルだけであり、かつ、３層目以降の耐火被覆材を取付けるステープルは、木質梁に到達しない長さのステープルであることを特徴とするので、１層目と２層目の耐火被覆材の落下を防止できるとともに、熱橋の影響を排除できる。
また、４層目以降の耐火被覆材の外面にメッシュシートが設けられたことを特徴とする木質梁の下面に設けられた耐火被覆層の自重の影響を小さくできて、木質梁の下面を覆うように設けられた耐火被覆層の落下を抑制できる。
また、吊手段は、２層目の耐火被覆材と３層目の耐火被覆材との間、４層目の耐火被覆材と５層目の耐火被覆材との間、６層目の耐火被覆材と７層目の耐火被覆材との間に、それぞれ設けられたことを特徴とするので、２層分毎に、吊手段を設けたことで、１つ１つの吊手段に加わる吊重量を小さくでき、耐火被覆層の落下抑制効果がより向上する。
また、耐火被覆層は、８枚の耐火被覆材を積層して形成された８層構造の耐火被覆層により構成されたことを特徴とするので、木質梁の下面を覆うように設けられた耐火被覆層の落下を抑制できるとともに、３時間耐火試験に合格できる８層構造の耐火被覆層を備えた木質耐火梁を提供できるようになった。 The wooden fireproof beam according to the present invention is a wooden fireproof beam comprising a wooden beam and a fireproof coating layer provided to cover both side surfaces and an underside of the wooden beam, the wooden beam being provided with a suspending means for preventing the fireproof coating layer provided to cover the underside of the wooden beam from falling, the suspending means comprising a mesh sheet provided continuously across the outer surfaces of the fireproof coating material forming the fireproof coating layer provided on both side surfaces of the wooden beam and the outer surface of the fireproof coating material forming the fireproof coating layer provided on the underside of the wooden beam, and a fixing means for fixing the mesh sheet to the outer surface of the fireproof coating material forming the fireproof coating layer, the fireproof coating layer being formed by laminating two or more layers of plate-shaped fireproof coating material, the mesh sheet being provided on the outer surface of the fireproof coating material forming any layer other than the outermost layer of the fireproof coating layer, The fixing means is an adhesive and a fastening material, and the adhesive is applied between the mesh sheet and the outer surface of the fireproof coating layer and to the outside of the mesh sheet through the mesh openings of the mesh sheet, and the fastening material is a staple having a pair of needle parts arranged in parallel at a predetermined interval and a needle head part connecting one end of the pair of needle parts, and the staple is characterized in that the predetermined interval between the pair of needle parts is larger than the size of the mesh opening of the mesh sheet, so that the fireproof coating layer provided to cover the lower surface of the wooden beam is suspended by the suspension means, and it is possible to provide a fireproof wooden beam that can suppress the fall of the fireproof coating layer provided to cover the lower surface of the wooden beam and exhibit the desired fireproof performance. In addition, even if the fireproof coating layer is a multi-layer fireproof coating layer, it is possible to provide a fireproof wooden beam that can suppress the fall of the fireproof coating layer provided to cover the lower surface of the wooden beam and exhibit the desired fireproof performance. In addition, it is possible to provide a fireproof wooden beam that is excellent in handleability and workability. In addition , since the mesh sheet and adhesive are integrated and adhered to the outer surface of the fire-resistant coating layer, the mesh sheet is firmly adhered and fixed to the outer surface of the fire-resistant coating layer , and the needle heads of the staples are always able to press and fix the wires of the mesh sheet against the outer surface of the fire-resistant coating material, so that the mesh sheet is firmly fixed to the outer surface of the fire-resistant coating material and the hanging support force of the mesh sheet is maintained, improving the effect of preventing the fire-resistant coating layer, which is provided to cover the underside of the wooden beam, from falling.
Furthermore, the only staples that penetrate and fix the wooden beams are those that attach the first layer of fire-resistant covering material to the wooden beams and those that attach the second layer of fire-resistant covering material to the wooden beams, and the staples that attach the third and subsequent layers of fire-resistant covering material are of a length that does not reach the wooden beams. This prevents the first and second layers of fire-resistant covering material from falling off and eliminates the effects of thermal bridges.
In addition, the effect of the weight of the fire-resistant coating layer provided on the underside of the wooden beam, which is characterized by having a mesh sheet provided on the outer surface of the fire-resistant coating material from the fourth layer onwards, can be reduced, and the fire-resistant coating layer provided to cover the underside of the wooden beam can be prevented from falling off.
Furthermore, the hanging means are provided between the second and third layers of fire-resistant covering material, between the fourth and fifth layers of fire-resistant covering material, and between the sixth and seventh layers of fire-resistant covering material. By providing the hanging means every two layers, the hanging weight applied to each hanging means can be reduced, further improving the effect of preventing the fire-resistant covering layer from falling.
In addition, the fire-resistant coating layer is characterized in that it is composed of an eight-layer fire-resistant coating layer formed by stacking eight sheets of fire-resistant coating material, which makes it possible to prevent the fire-resistant coating layer provided to cover the underside of the wooden beam from falling off, and it is also possible to provide a wooden fire-resistant beam equipped with an eight-layer fire-resistant coating layer that can pass a three-hour fire resistance test.

木質耐火梁を示す断面図（実施形態１）。FIG. 1 is a cross-sectional view showing a wood fire-resistant beam (embodiment 1). 木質耐火梁を示す断面図（実施形態２）。FIG. 4 is a cross-sectional view showing a wood fire-resistant beam (embodiment 2). 木質耐火梁を示す断面図（実施形態３）。FIG. 13 is a cross-sectional view showing a wood fire-resistant beam (third embodiment). 木質耐火梁を示す断面図（従来例）。Cross-sectional view showing a wooden fire-resistant beam (conventional example).

実施形態１
図１に示すように、実施形態１に係る木質耐火梁１は、荷重を支持する荷重支持部としての断面四角形状の木質梁２と、当該木質梁２の両方の側面２１，２１と下面２２とを覆うように設けられた耐火被覆層３と、木質梁２の下面２２を覆うように設けられた耐火被覆層３の落下を抑制する吊手段４とを備える。また、木質梁２の上面には、床１０が構築される。 EMBODIMENT 1
As shown in Fig. 1, the fire-resistant wooden beam 1 according to the first embodiment includes a wooden beam 2 having a rectangular cross section as a load-bearing part for supporting a load, a fire-resistant coating layer 3 provided to cover both side surfaces 21, 21 and a bottom surface 22 of the wooden beam 2, and a hanging means 4 for preventing the fire-resistant coating layer 3 provided to cover the bottom surface 22 of the wooden beam 2 from falling. A floor 10 is constructed on the top surface of the wooden beam 2.

木質梁２は、例えば、ＣＬＴ（Cross Laminated Timber（直交集成板））又は集成材又はＬＶＬ（Laminated Veneer Lumber（単層積層材））又は無垢材等の木により形成された梁である。
尚、ＣＬＴとは、農林水産省告示第３０７９号に規定されたように、「ひき板又は小角材（これらをその繊維方向を互いにほぼ平行にして長さ方向に接合接着して調整したものを含む。）をその繊維方向を互いにほぼ平行にして幅方向に並べ又は接着したものを、主としてその繊維方向を互いにほぼ直角にして積層接着し３層以上の構造を持たせた一般材」である。
即ち、ＣＬＴは、一般に、張り合わせる板の繊維方向が直交するように複数の板を張り合わせて構成された木材であり、直交集成板と呼ばれている。
また、集成材は、一般に、張り合わせる板の繊維方向が並行方向となるように複数の板を張り合わせて構成された木材である。
また、ＬＶＬは、一般に、複数の単板（ベニヤ）を、単板の繊維方向に平行に積層して接着した木材である。 The wooden beam 2 is a beam made of wood such as CLT (Cross Laminated Timber), laminated timber, LVL (Laminated Veneer Lumber), or solid wood.
Additionally, CLT, as defined in Notification No. 3079 of the Ministry of Agriculture, Forestry and Fisheries, is "a general material made by arranging or gluing planks or small square timber (including those which have been adjusted by joining and gluing them lengthwise with their grain directions roughly parallel to each other) in the width direction with their grain directions roughly parallel to each other, and then laminating and gluing them together mainly with their grain directions roughly perpendicular to each other to create a structure of three or more layers."
That is, CLT is generally a type of wood constructed by gluing together multiple boards so that the grain directions of the boards cross at right angles, and is known as cross-laminated timber.
Generally, laminated lumber is wood made by bonding together a number of boards so that the grain directions of the boards are parallel to each other.
Moreover, LVL is generally a wood material in which a plurality of veneer panels are laminated and glued together in a manner that is parallel to the grain direction of the veneer panels.

実施形態１では、耐火被覆層３が、例えばせっこうボード等の板状の耐火被覆材３０の１枚分の厚さの１層の耐火被覆層により構成された例を示している。 In the first embodiment, the fire-resistant coating layer 3 is an example formed of a single fire-resistant coating layer having a thickness equivalent to that of one sheet of plate-shaped fire-resistant coating material 30, such as gypsum board.

吊手段４は、木質梁２の両方の側面２１，２１に設けられた耐火被覆層３を形成する耐火被覆材３０の外側の面及び木質梁２の下面２２に設けられた耐火被覆層３を形成する耐火被覆材３０の外側の面に亘って連続するように設けられた面材５と、当該面材５を耐火被覆層３の外側の面に固定する固定手段６とを備えた構成とした。
面材５は、耐火被覆層３を形成する耐火被覆材３０の外側の面の全体に設けられる。
ここで、「耐火被覆層３を形成する耐火被覆材３０の外側の面」とは、実施形態１のように、耐火被覆層３が、板状の耐火被覆材３０の１枚分の厚さの１層の耐火被覆層により構成されている場合には、当該耐火被覆層３を構成する耐火被覆材３０の外面３１を意味し、また、後述する実施形態２，３のように、耐火被覆層３が板状の耐火被覆材３０を２枚以上重ねて形成された２層以上の耐火被覆層により構成されている場合には、最外層以外のいずれか任意の層を形成する耐火被覆材３０の外面３１を意味する。 The hanging means 4 is configured to include a surface material 5 that is provided continuously over the outer surface of the fire-resistant coating material 30 that forms the fire-resistant coating layer 3 provided on both side surfaces 21, 21 of the wooden beam 2 and the outer surface of the fire-resistant coating material 30 that forms the fire-resistant coating layer 3 provided on the underside 22 of the wooden beam 2, and a fixing means 6 that fixes the surface material 5 to the outer surface of the fire-resistant coating layer 3.
The face material 5 is provided on the entire outer surface of the fire-resistant coating material 30 that forms the fire-resistant coating layer 3 .
Here, "the outer surface of the fire-resistant coating material 30 that forms the fire-resistant coating layer 3" means the outer surface 31 of the fire-resistant coating material 30 that forms the fire-resistant coating layer 3 when the fire-resistant coating layer 3 is composed of a single fire-resistant coating layer with the thickness of one plate-shaped fire-resistant coating material 30, as in embodiment 1, or means the outer surface 31 of the fire-resistant coating material 30 that forms any layer other than the outermost layer when the fire-resistant coating layer 3 is composed of two or more fire-resistant coating layers formed by stacking two or more plate-shaped fire-resistant coating materials 30, as in embodiments 2 and 3 described below.

面材５は、例えば薄厚（例えば厚さ１ｍｍ以下）のメッシュシートである。
固定手段６は、例えば接着剤６１及び留付材６２である。 The face material 5 is, for example, a thin mesh sheet (for example, 1 mm or less in thickness).
The fixing means 6 is, for example, an adhesive 61 and a fastening material 62 .

実施形態１に係る木質耐火梁１の具体的構成の一例を図１を参照しながら説明する。
１層の耐火被覆層３を形成する板状の耐火被覆材３０としては、板厚１２．５ｍｍの普通硬質せっこうボード（以下、単に、せっこうボードという）を用いた。
当該せっこうボードの貼付面の全面に図外の無機系の接着剤が塗布されて当該せっこうボードの貼付面が木質梁２の側面２１や下面２２に押し付けられた状態とされ、さらに、留付材６０として針部の長さ２２ｍｍ針部間幅４ｍｍのステープルを用い、当該ステープルの針部がせっこうボードを貫通して木質梁２に打ち込まれることによって、木質梁２の両方の側面２１，２１と下面２２とにせっこうボードが取付けられる。以上により、木質梁２の両方の側面２１，２１と下面２２とを覆う１層の耐火被覆層３が形成される。 An example of a specific configuration of a fire-resistant wooden beam 1 according to the first embodiment will be described with reference to FIG.
As the plate-shaped fireproof coating material 30 forming one fireproof coating layer 3, a normal hard gypsum board (hereinafter simply referred to as gypsum board) having a plate thickness of 12.5 mm was used.
An inorganic adhesive (not shown) is applied to the entire attachment surface of the gypsum board, and the attachment surface of the gypsum board is pressed against the side surface 21 and underside 22 of the wooden beam 2, and staples with needle lengths of 22 mm and needle spacing of 4 mm are used as fastening materials 60, and the needles of the staples are driven through the gypsum board and into the wooden beam 2, thereby attaching the gypsum board to both side surfaces 21, 21 and the underside 22 of the wooden beam 2. As a result of the above, one fire-resistant coating layer 3 is formed which covers both side surfaces 21, 21 and the underside 22 of the wooden beam 2.

尚、ステープルは、所定の間隔を隔てて平行（平行又は略平行を含む）に設けられた一対の針部と、一対の針部の一端同士を連結する針頭部とを備えた、コ字状の留付針であり、ステープル釘打機を用いて打ち込まれる。 The staple is a U-shaped fastening needle that has a pair of needle parts that are arranged parallel (including parallel or nearly parallel) at a specified distance and a needle head that connects one end of the pair of needle parts, and is driven into the stapler using a staple nailer.

次に、図１に示すように、木質梁２の両方の側面２１，２１に設けられた耐火被覆層３を形成するせっこうボードの外面３１及び木質梁２の下面２２に設けられた耐火被覆層３を形成するせっこうボードの外面３１に亘って連続するように面材５を取付ける。
面材５としては、ガラス繊維強化プラスチック（グラスファイバー）製のメッシュシート（テープ）を用いた。また、当該メッシュシートとしては、厚さが０．２ｍｍ、目開きの寸法が３ｍｍのメッシュシートを用いた。
例えば、せっこうボードの外面３１に当該メッシュシートを設置して当該メッシュシートの上から無機系の接着剤６１を扱くようにして塗りつけることで、メッシュシートと接着剤６１とが一体化した状態でせっこうボードの外面３１にメッシュシートが接着されるようになる。
さらに、留付材６２として針部の長さ２２ｍｍ針部間幅４ｍｍのステープルを用い、当該ステープルの針部が、せっこうボードの外面３１に接着されたメッシュシート、及び、せっこうボードを貫通して木質梁２に打ち込まれることにより、当該メッシュシートが、木質梁２に取付けられるとともに、せっこうボードの外面３１に固定されるようになる。 Next, as shown in FIG. 1 , a surface material 5 is attached so as to extend continuously over the outer surface 31 of the gypsum board that forms the fire-resistant coating layer 3 provided on both side surfaces 21, 21 of the wooden beam 2 and the outer surface 31 of the gypsum board that forms the fire-resistant coating layer 3 provided on the underside 22 of the wooden beam 2.
A mesh sheet (tape) made of glass fiber reinforced plastic (glass fiber) was used as the face material 5. The mesh sheet used had a thickness of 0.2 mm and an opening size of 3 mm.
For example, the mesh sheet is placed on the outer surface 31 of a gypsum board and an inorganic adhesive 61 is gently spread over the mesh sheet, so that the mesh sheet is bonded to the outer surface 31 of the gypsum board with the mesh sheet and the adhesive 61 integrated together.
Furthermore, staples having a needle length of 22 mm and a needle spacing of 4 mm are used as fastening material 62, and the needles of the staples are driven into the mesh sheet adhered to the outer surface 31 of the gypsum board, and through the gypsum board, into the wooden beam 2, so that the mesh sheet is attached to the wooden beam 2 and fixed to the outer surface 31 of the gypsum board.

以上により、木質梁２の両方の側面２１，２１に設けられた耐火被覆層３を形成するせっこうボードの外面３１及び木質梁２の下面２２に設けられた耐火被覆層３を形成するせっこうボードの外面３１に亘って連続するように設置された面材５としてのメッシュシートが、接着剤６１及びステープル（留付材６２）により構成された固定手段６によって、１層の耐火被覆層３を形成する耐火被覆材３０としてのせっこうボードの外面３１に固定された木質耐火梁１が構成される。
尚、実施形態１に係る木質耐火梁１では、メッシュシートを覆う図外の化粧材（表面材）を設けることが好ましい。 As a result of the above, a wooden fire-resistant beam 1 is constructed in which a mesh sheet serving as a surface material 5 is installed continuously over the outer surface 31 of the gypsum board that forms the fire-resistant coating layer 3 on both side surfaces 21, 21 of the wooden beam 2 and the outer surface 31 of the gypsum board that forms the fire-resistant coating layer 3 on the underside 22 of the wooden beam 2, and is fixed to the outer surface 31 of the gypsum board as a fire-resistant coating material 30 that forms one layer of fire-resistant coating layer 3 by fixing means 6 consisting of adhesive 61 and staples (fastening material 62).
In addition, in the wood fire-resistant beam 1 according to the first embodiment, it is preferable to provide a decorative material (surface material) not shown in the figure that covers the mesh sheet.

図１のＡ部拡大断面図（メッシュシート（面材５）と接着剤６１との関係を示す拡大断面図）に示すように、面材５としてメッシュシートを用いた場合、メッシュ開口５１を介して、メッシュシート（面材５）とせっこうボード（耐火被覆材３０）の外面３１との間、及び、メッシュシート（面材５）の外側に、接着剤６１が行き渡り、メッシュシートと接着剤６１とが一体化された状態でせっこうボードの外面３１に接着されることになるため、メッシュシートがせっこうボードの外面３１に強固に接着されて固定された状態となり、メッシュシートによる吊支持力が維持される。 As shown in the enlarged cross-sectional view of part A in FIG. 1 (an enlarged cross-sectional view showing the relationship between the mesh sheet (face material 5) and the adhesive 61), when a mesh sheet is used as the face material 5, the adhesive 61 spreads between the mesh sheet (face material 5) and the outer surface 31 of the gypsum board (fire-resistant covering material 30) and to the outside of the mesh sheet (face material 5) through the mesh openings 51, and the mesh sheet and adhesive 61 are bonded together to the outer surface 31 of the gypsum board, so that the mesh sheet is firmly bonded and fixed to the outer surface 31 of the gypsum board, and the suspension support force provided by the mesh sheet is maintained.

また、図１のＢ部拡大正面図（メッシュシート（面材５）とステープル（留付材６２）との関係を示す拡大正面図）に示すように、メッシュシート（面材５）として、目開きの寸法ａが３ｍｍのメッシュシートを用いるとともに、針部６３，６３の長さ２２ｍｍ、針部間幅ｂが４ｍｍのステープル（留付材６２）を用いたので、当該ステープルを打ち込んだ場合、ステープルの両方の針部６３，６３が、メッシュシートの線材５２を挟んで隣り合うメッシュ開口５１，５１を通過して、一対の針部６３，６３の一端同士を連結する針頭部６４が、メッシュシートの線材５２をせっこうボード（耐火被覆材３０）の外面３１に押し付けるようになる。
即ち、メッシュシートの目開きの寸法ａとステープルの針部間幅ｂとの関係が、ａ＜ｂとなるような、メッシュシートとステープルとを使用したことにより、ステープルの針頭部６４が、必ず、メッシュシートの線材５２をせっこうボード（耐火被覆材３０）の外面３１に押し付けて固定できるようになるため、メッシュシート（面材５）がせっこうボード（耐火被覆材３０）の外面３１に強固に固定された状態となり、メッシュシートによる吊支持力が維持される。 As shown in the enlarged front view of portion B in FIG. 1 (an enlarged front view showing the relationship between the mesh sheet (face material 5) and the staples (fastening material 62)), a mesh sheet having an opening dimension a of 3 mm was used as the mesh sheet (face material 5), and staples (fastening material 62) having needle portions 63, 63 of 22 mm in length and a needle-to-needle width b of 4 mm were used. Therefore, when the staples are driven into the groove, both needle portions 63, 63 of the staples pass through adjacent mesh openings 51, 51 sandwiching the wire material 52 of the mesh sheet, and the needle head portions 64 connecting one ends of the pair of needle portions 63, 63 press the wire material 52 of the mesh sheet against the outer surface 31 of the gypsum board (fire-resistant covering material 30).
In other words, by using a mesh sheet and staples such that the relationship between the mesh opening dimension a of the mesh sheet and the needle spacing b of the staples is a < b, the needle heads 64 of the staples can always press and fix the wires 52 of the mesh sheet against the outer surface 31 of the gypsum board (fire-resistant covering material 30), so that the mesh sheet (face material 5) is firmly fixed to the outer surface 31 of the gypsum board (fire-resistant covering material 30), and the hanging support force provided by the mesh sheet is maintained.

即ち、面材５としてのメッシュシートが、木質梁２の両方の側面２１，２１に設けられた耐火被覆層３を形成する耐火被覆材３０としてのせっこうボードの外面３１及び木質梁の下面２２に設けられた耐火被覆層３を形成する耐火被覆材３０としてのせっこうボードの外面３１に亘って連続するように設けられて、固定手段６により、耐火被覆層３の外面３１に強固に固定された構成の木質耐火梁１となる。 In other words, the mesh sheet as the facing material 5 is provided so as to be continuous across the outer surface 31 of the gypsum board as the fire-resistant coating material 30 forming the fire-resistant coating layer 3 provided on both side surfaces 21, 21 of the wooden beam 2 and the outer surface 31 of the gypsum board as the fire-resistant coating material 30 forming the fire-resistant coating layer 3 provided on the underside 22 of the wooden beam, and is firmly fixed to the outer surface 31 of the fire-resistant coating layer 3 by the fixing means 6 to form a wooden fire-resistant beam 1.

従って、実施形態１に係る木質耐火梁１によれば、面材５と当該面材５を木質梁２の両方の側面２１，２１及び下面２２に設けられた耐火被覆層３の外面３１に固定する固定手段６とで構成された吊手段４を備えたので、当該吊手段４によって、木質梁２の下面２２を覆うように設けられた耐火被覆層３が吊られた状態となる。
即ち、木質梁２の両方の側面２１，２１に設けられた耐火被覆層３の外面３１及び木質梁２の下面２２に設けられた耐火被覆層３の外面３１に亘って連続するように設けられて、かつ、固定手段６により、耐火被覆層３の外面３１に強固に固定された面材５を備えたので、耐火被覆層３の外面３１に強固に固定された面材５によって、木質梁２の下面２２を覆うように設けられた耐火被覆層３が吊られた状態となるため、木質梁２の下面２２を覆うように設けられた耐火被覆層３の落下を、火災時などに抑制できるようになり、所期の耐火性能を発揮できる木質耐火梁１を得ることができるようになった。
また、面材５としてメッシュシートを用いたので、面材５を接着剤６１や留付材６２で耐火被覆材３０の外面３１に固定しやすくなり、取扱性、施工性に優れた木質耐火梁１を提供できる。 Therefore, according to the wooden fire-resistant beam 1 of embodiment 1, a hanging means 4 is provided which is composed of a surface material 5 and a fixing means 6 for fixing the surface material 5 to the outer surface 31 of the fire-resistant coating layer 3 provided on both side surfaces 21, 21 and the underside 22 of the wooden beam 2, so that the fire-resistant coating layer 3 provided to cover the underside 22 of the wooden beam 2 is suspended by the hanging means 4.
In other words, the surface material 5 is provided so as to extend continuously over the outer surface 31 of the fire-resistant coating layer 3 provided on both side surfaces 21, 21 of the wooden beam 2 and the outer surface 31 of the fire-resistant coating layer 3 provided on the underside 22 of the wooden beam 2, and is firmly fixed to the outer surface 31 of the fire-resistant coating layer 3 by fixing means 6.As a result, the fire-resistant coating layer 3 provided to cover the underside 22 of the wooden beam 2 is suspended by the surface material 5 firmly fixed to the outer surface 31 of the fire-resistant coating layer 3, so that the falling of the fire-resistant coating layer 3 provided to cover the underside 22 of the wooden beam 2 can be suppressed in the event of a fire, etc., and a wooden fire-resistant beam 1 capable of exhibiting the desired fire resistance performance can be obtained.
Furthermore, since a mesh sheet is used as the surface material 5, it becomes easier to fix the surface material 5 to the outer surface 31 of the fire-resistant covering material 30 with adhesive 61 or fastening material 62, thereby providing a wooden fire-resistant beam 1 with excellent handling and workability.

また、面材５としてのメッシュシートを耐火被覆層３の外面３１に固定するための接着剤６１を、メッシュシートのメッシュの開口５１を介して、メッシュシートと耐火被覆層３の外面３１との間、及び、メッシュシートの外側に行き渡るように塗布したので、メッシュシートと接着剤６１とが一体化された状態で耐火被覆層３の外面３１に接着されることになるため、メッシュシートが耐火被覆層３の外面３１に強固に接着されて固定された状態となり、メッシュシートによる吊支持力が向上するので、木質梁２の下面２２を覆うように設けられた耐火被覆層３の落下抑制効果が向上する。 In addition, the adhesive 61 for fixing the mesh sheet as the facing material 5 to the outer surface 31 of the fire-resistant coating layer 3 is applied between the mesh sheet and the outer surface 31 of the fire-resistant coating layer 3, and to the outside of the mesh sheet, through the mesh openings 51 of the mesh sheet. This means that the mesh sheet and the adhesive 61 are bonded together and bonded to the outer surface 31 of the fire-resistant coating layer 3. This means that the mesh sheet is firmly bonded and fixed to the outer surface 31 of the fire-resistant coating layer 3, improving the hanging support force of the mesh sheet, and improving the fall prevention effect of the fire-resistant coating layer 3 provided to cover the underside 22 of the wooden beam 2.

また、留付材６２として、所定の間隔ｂを隔てて平行に設けられた一対の針部６３，６３と、一対の針部６３，６３の一端同士を連結する針頭部６４とを備えたステープルを用い、当該ステープルとして、一対の針部６３，６３間の所定の間隔ｂが、メッシュシートのメッシュの目開きの寸法ａよりも大きいものを使用したので、留付材６２としてのステープルの針頭部６４が、必ず、メッシュシートの線材５２を耐火被覆層３の外面３１に押し付けて固定できるようになるため、メッシュシート（面材５）が耐火被覆層３の外面３１に強固に固定された状態となり、メッシュシートによる吊支持力が向上するので、木質梁２の下面２２を覆うように設けられた耐火被覆層３の落下抑制効果が向上する。 As the fastening material 62, a staple having a pair of needles 63, 63 arranged in parallel with a predetermined distance b therebetween and a needle head 64 connecting one end of the pair of needles 63, 63 is used, and the predetermined distance b between the pair of needles 63, 63 is larger than the size a of the mesh opening of the mesh sheet. Therefore, the needle head 64 of the staple as the fastening material 62 can always press and fix the wire 52 of the mesh sheet against the outer surface 31 of the fire-resistant coating layer 3. As a result, the mesh sheet (face material 5) is firmly fixed to the outer surface 31 of the fire-resistant coating layer 3, and the suspension support force of the mesh sheet is improved, which improves the fall prevention effect of the fire-resistant coating layer 3 provided to cover the lower surface 22 of the wooden beam 2.

実施形態２
図２に示すように、実施形態２に係る木質耐火梁１は、木質梁２の両方の側面２１，２１と下面２２とを覆うように設けられた耐火被覆層３が、所定厚さの板状の耐火被覆材３０を複数枚積層して形成された複数層構造の耐火被覆層により構成されたものとした。
例えば、図２に示すように、耐火被覆層３は、８枚の耐火被覆材３０，３０…を積層して形成された８層構造の耐火被覆層により構成されたものとした。
尚、図２において、実施形態１の図１に示した部分と同一部分又は相当部分には同一符号を付し、詳細な説明は省略する。 EMBODIMENT 2
As shown in Figure 2, in the wood fire-resistant beam 1 of embodiment 2, the fire-resistant coating layer 3 provided to cover both side surfaces 21, 21 and the underside 22 of the wood beam 2 is composed of a fire-resistant coating layer with a multi-layer structure formed by stacking multiple sheets of plate-shaped fire-resistant coating material 30 of a predetermined thickness.
For example, as shown in FIG. 2, the fire-resistant coating layer 3 is configured of an eight-layer fire-resistant coating layer formed by laminating eight fire-resistant coating materials 30, 30 . . .
In FIG. 2, the same or corresponding parts as those shown in FIG. 1 of the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

実施形態２に係る木質耐火梁１の具体的構成の一例を図２を参照しながら説明する。
８層の耐火被覆層３を形成する板状の耐火被覆材３０としては、せっこうボードと火山性ガラス質複層板とを用いた。 An example of a specific configuration of the fire-resistant wooden beam 1 according to the second embodiment will be described with reference to FIG.
As the plate-shaped fire-resistant covering material 30 forming the eight-layer fire-resistant covering layer 3, a gypsum board and a volcanic vitreous laminate plate were used.

８層の耐火被覆層３を構成する８枚のせっこうボードのうち、木質梁２に近い側から１層目を形成する耐火被覆材３０としての厚さ１２．５ｍｍのせっこうボードは、当該せっこうボードの貼付面の全面に図外の接着剤が塗布されて当該貼付面が木質梁２の側面２１，２１や下面２２に押し付けられた状態とされ、さらに、留付材６０としての針部の長さ３８ｍｍ針部間幅４ｍｍのステープルが当該せっこうボードを貫通して木質梁２に打ち込まれることにより、木質梁２に取付けられる。
また、木質梁２に近い側から２層目を形成する耐火被覆材３０としての厚さ１２．５ｍｍのせっこうボードも１層目のせっこうボードと同様に、木質梁２に取付けられる。この場合、留付材６０としての針部の長さ３８ｍｍ針部間幅４ｍｍのステープルが当該２層目のせっこうボード及び１層目のせっこうボードを貫通して木質梁２に打ち込まれることにより、当該２層目のせっこうボードが木質梁２に取付けられる。 Of the eight gypsum boards that make up the eight-layer fire-resistant coating layer 3, the gypsum board with a thickness of 12.5 mm that forms the first layer from the side closest to the wooden beam 2 is coated with adhesive (not shown) over the entire attachment surface of the gypsum board so that the attachment surface is pressed against the side surfaces 21, 21 and underside 22 of the wooden beam 2. Furthermore, staples with needle lengths of 38 mm and needle spacing widths of 4 mm that serve as fastening materials 60 are driven into the wooden beam 2 through the gypsum board, thereby attaching it to the wooden beam 2.
Similarly to the first layer of gypsum board, a 12.5 mm thick gypsum board serving as a fireproof covering material 30 forming the second layer from the side closer to the wooden beam 2 is also attached to the wooden beam 2. In this case, the second layer of gypsum board is attached to the wooden beam 2 by driving a staple having a needle length of 38 mm and a needle distance of 4 mm serving as a fastening material 60 into the wooden beam 2 through the second layer of gypsum board and the first layer of gypsum board.

木質梁２に近い側から３層目、４層目、５層目を形成する耐火被覆材３０としての厚さ１２．５ｍｍのせっこうボードは、当該せっこうボードの貼付面の全面に図外の接着剤が塗布されて当該貼付面が前層のせっこうボードの外面３１に押付けられた状態とされ、さらに、留付材６０としての針部の長さ２２ｍｍ針部間幅４ｍｍのステープルが当該せっこうボードを貫通して前層のせっこうボードに打ち込まれることにより、前層のせっこうボードに取付けられる。 The gypsum boards, each 12.5 mm thick, which form the third, fourth, and fifth layers from the side closest to the wooden beam 2, are attached to the gypsum boards by applying adhesive (not shown) to the entire attachment surface of the gypsum boards, which is pressed against the outer surface 31 of the gypsum board of the previous layer. Furthermore, staples with needle lengths of 22 mm and needle spacing of 4 mm serving as fastening materials 60 are driven through the gypsum boards and into the gypsum board of the previous layer, thereby attaching the gypsum boards to the gypsum board of the previous layer.

木質梁２に近い側から６層目を形成する耐火被覆材３０としての厚さ９．５ｍｍのせっこうボードは、当該せっこうボードの貼付面の全面に図外の接着剤が塗布されて当該貼付面が前層のせっこうボードの外面３１に押付けられた状態とされ、さらに、留付材６０としての針部の長さ２２ｍｍ針部間幅４ｍｍのステープルが当該せっこうボードを貫通して前層のせっこうボードに打ち込まれることにより、前層のせっこうボードに取付けられる。 The gypsum board, 9.5 mm thick, which serves as the fireproof covering material 30 forming the sixth layer from the side closest to the wooden beam 2, has adhesive applied to the entire attachment surface of the gypsum board (not shown) so that the attachment surface is pressed against the outer surface 31 of the gypsum board of the previous layer, and is attached to the gypsum board of the previous layer by driving staples 60, each staple having a needle length of 22 mm and a needle width of 4 mm, through the gypsum board and into the gypsum board of the previous layer.

木質梁２に近い側から７層目を形成する耐火被覆材３０としては、厚さ６．０ｍｍの火山性ガラス質複層板を用いた。この火山性ガラス質複層板は、当該火山性ガラス質複層板の貼付面の全面に図外の接着剤が塗布されて当該貼付面が前層のせっこうボードの外面３１に押付けられた状態とされ、さらに、留付材６０としての針部の長さ２２ｍｍ針部間幅４ｍｍのステープルが当該せっこうボードを貫通して前層のせっこうボードに打ち込まれることにより、前層及び前々層のせっこうボードに取付けられる。 A 6.0 mm thick volcanic glass laminate was used as the fireproof coating material 30 forming the seventh layer from the side closest to the wooden beam 2. This volcanic glass laminate is attached to the previous and previous layers of gypsum board by applying an adhesive (not shown) to the entire surface of the attachment surface of the volcanic glass laminate, with the attachment surface pressed against the outer surface 31 of the previous layer of gypsum board, and then by driving a staple with a needle length of 22 mm and a needle width of 4 mm as a fastening material 60 through the gypsum board and into the previous layer of gypsum board.

木質梁２に近い側から８層目、即ち、耐火被覆層３の最外層を形成する耐火被覆材３０としての厚さ９．５ｍｍのせっこうボードは、当該せっこうボードの貼付面の全面に図外の接着剤が塗布されて当該貼付面が前層の火山性ガラス質複層板の外面３１に押付けられた状態とされ、さらに、留付材６０としての針部の長さ２２ｍｍ針部間幅４ｍｍのステープルが当該せっこうボードを貫通して前層の火山性ガラス質複層板及び前々層のせっこうボード及びに打ち込まれることにより、前層の火山性ガラス質複層板及び前々層のせっこうボードに取付けられる。 The 9.5 mm thick gypsum board that forms the 8th layer from the side closest to the wooden beam 2, i.e., the outermost layer of the fire-resistant coating layer 3, is attached to the previous layer of volcanic vitreous laminate board and the previous layer of gypsum board by applying adhesive (not shown) to the entire attachment surface of the gypsum board, which is pressed against the outer surface 31 of the previous layer of volcanic vitreous laminate board. Furthermore, staples with needle lengths of 22 mm and needle spacing of 4 mm that serve as fastening materials 60 are driven through the gypsum board and into the previous layer of volcanic vitreous laminate board and the gypsum board before the previous layer, thereby attaching the gypsum board to the previous layer of volcanic vitreous laminate board and the gypsum board before the previous layer.

実施形態２では、例えば図２に示すように、４層目のせっこうボードと５層目のせっこうボードとの間に、実施形態１と同様な面材５としてのメッシュシートを設けて、当該メッシュシートを実施形態１と同様な接着剤６１と留付材６２とで構成された固定手段６を用いて、耐火被覆層３の４層目を形成するせっこうボードの外面３１に固定するようにした。
つまり、４層目のせっこうボードと５層目のせっこうボードとの間に、吊手段４を設けた構成とした。 In the second embodiment, as shown in FIG. 2, for example, a mesh sheet is provided as a facing material 5 similar to that in the first embodiment between the fourth layer and the fifth layer of gypsum board, and the mesh sheet is fixed to the outer surface 31 of the gypsum board forming the fourth layer of the fire-resistant coating layer 3 using a fixing means 6 composed of an adhesive 61 and a fastening material 62 similar to that in the first embodiment.
That is, the suspension means 4 is provided between the fourth layer of gypsum board and the fifth layer of gypsum board.

従って、実施形態２に係る木質耐火梁１によれば、木質梁２の下面２２を覆うように設けられた耐火被覆層３の１層目から４層目までのせっこうボードの部分が、吊手段４によって吊られた状態となる。
即ち、木質梁２の下面２２を覆うように設けられた耐火被覆層３の１層目から４層目までのせっこうボードの部分が、木質梁２の両方の側面２１，２１に設けられた耐火被覆層３を形成する４層目のせっこうボードの外面３１及び木質梁の下面２２に設けられた耐火被覆層３を形成する４層目のせっこうボードの外面３１に亘って連続するように設けられて、かつ、固定手段６により当該耐火被覆層３の４層目のせっこうボードの外面３１に固定された面材５によって、吊られた状態となるため、木質梁２の下面２２を覆うように設けられた耐火被覆層３の落下を、火災時などに抑制できるようになり、所期の耐火性能を十分に発揮できる木質耐火梁１を得ることができるようになった。
つまり、実施形態２に係る木質耐火梁１によれば、耐火被覆層３が複数層の耐火被覆層であっても、木質梁２の下面２２を覆うように設けられた耐火被覆層３の落下を、火災時などに抑制できるようになり、所期の耐火性能を十分に発揮できる木質耐火梁１となる。 Therefore, according to the wooden fire-resistant beam 1 of embodiment 2, the gypsum board portions from the first layer to the fourth layer of the fire-resistant coating layer 3 arranged to cover the underside 22 of the wooden beam 2 are suspended by the suspension means 4.
In other words, the first to fourth layers of the gypsum board of the fire-resistant coating layer 3, which is provided to cover the underside 22 of the wooden beam 2, are provided so as to be continuous over the outer surface 31 of the fourth layer of gypsum board which forms the fire-resistant coating layer 3 provided on both side surfaces 21, 21 of the wooden beam 2 and the outer surface 31 of the fourth layer of gypsum board which forms the fire-resistant coating layer 3 provided on the underside 22 of the wooden beam, and are in a suspended state by the facing material 5 which is fixed to the outer surface 31 of the fourth layer of gypsum board of the fire-resistant coating layer 3 by the fixing means 6. Therefore, it is possible to prevent the fire-resistant coating layer 3 provided to cover the underside 22 of the wooden beam 2 from falling in the event of a fire, etc., and it is possible to obtain a wooden fire-resistant beam 1 which can fully exhibit the desired fire resistance performance.
In other words, according to the wood fire-resistant beam 1 of embodiment 2, even if the fire-resistant coating layer 3 is a multi-layer fire-resistant coating layer, the falling of the fire-resistant coating layer 3 provided to cover the underside 22 of the wood beam 2 can be suppressed in the event of a fire, etc., resulting in a wood fire-resistant beam 1 that can fully exhibit the desired fire resistance performance.

比較例１
実施形態２で説明した木質耐火梁１との比較例１について説明する。
比較例１は、実施形態２で説明した木質耐火梁１の吊手段４を備えず、かつ、木質梁２に近い側から１層目及び２層目を形成するせっこうボードの留付材６０として針部の長さ２２ｍｍ針部間幅４ｍｍのステープルを用いた構成の木質耐火梁とした。
当該比較例１の木質耐火梁の３時間耐火試験を実施した結果、木質梁２の下面２２を覆うように設けられた８層の耐火被覆層３を形成する耐火被覆材３０，３０…のすべてが落下して、木質梁２の下面２２が焦げてしまったため、３時間耐火試験には合格できなかった。 Comparative Example 1
A comparative example 1 of the wood fire-resistant beam 1 described in the second embodiment will be described.
Comparative Example 1 was a wooden fire-resistant beam that did not have the hanging means 4 of the wooden fire-resistant beam 1 described in embodiment 2, and was configured using staples with a needle length of 22 mm and a needle spacing of 4 mm as fastening materials 60 for the gypsum board that forms the first and second layers from the side closer to the wooden beam 2.
As a result of conducting a three-hour fire resistance test on the wooden fire-resistant beam of Comparative Example 1, all of the fire-resistant coating materials 30, 30... forming the eight layers of fire-resistant coating layer 3 provided to cover the underside 22 of the wooden beam 2 fell off, and the underside 22 of the wooden beam 2 was scorched, so that the three-hour fire resistance test could not be passed.

比較例２
比較例１の木質耐火梁において、８層の耐火被覆層における木質梁２に近い側から１層目及び２層目を形成するせっこうボードの留付材６０としてのステープルを、針部の長さ２２ｍｍ針部間幅４ｍｍのステープルから針部の長さ３８ｍｍ針部間幅４ｍｍのステープルに変更した構成とした。
当該比較例２の木質耐火梁の３時間耐火試験を実施した結果、木質梁２の下面２２を覆うように設けられた８層の耐火被覆層３の３層目以降を形成する耐火被覆材３０，３０…、即ち、６層分の耐火被覆材３０，３０…が落下して、木質梁２の下面２２が焦げてしまったため、３時間耐火試験には合格できなかった。 Comparative Example 2
In the wooden fire-resistant beam of Comparative Example 1, the staples used as fastening materials 60 for the gypsum boards forming the first and second layers of the eight-layer fire-resistant coating layer from the side closest to the wooden beam 2 were changed from staples with a needle length of 22 mm and a spacing width of 4 mm to staples with a needle length of 38 mm and a spacing width of 4 mm.
As a result of conducting a three-hour fire resistance test on the wooden fire-resistant beam of Comparative Example 2, the fire-resistant coating materials 30, 30... forming the third layer and beyond of the eight-layer fire-resistant coating layer 3 provided to cover the underside 22 of the wooden beam 2, i.e., six layers of fire-resistant coating materials 30, 30..., fell off, causing the underside 22 of the wooden beam 2 to scorch, and the three-hour fire resistance test was not passed.

比較例３
比較例１や比較例２で用いた留付材６０としてのステープルの代わりに、３層目以降の耐火被覆材３０の外面３１から木質梁２に貫入して固定される長さの釘や傘釘等の留付材を用いて、１層目から３層目以降までの３層以上の耐火被覆層３を形成する耐火被覆材３０，３０…を木質梁２に固定した構成の木質耐火梁とすることも考えられる。
比較例３の木質耐火梁の場合、比較例１や比較例２の木質耐火梁と比べて、木質梁２の下面２２を覆うように設けられた耐火被覆層３の落下を抑制できると想定される。
しかしながら、比較例３の木質耐火梁の場合、３時間耐火試験において、木質梁２に貫入して固定される釘や傘釘等の留付材の頭部が、火源側に近い位置に設けられることになるため、火源からの熱が釘や傘釘等の留付材を介して木質梁２の内部に伝達される熱橋現象によって留付材が接触する木質梁２の部分が焦げてしまう可能性が高く、３時間耐火試験に合格できない可能性が高い。 Comparative Example 3
Instead of the staples used as fastening material 60 in Comparative Examples 1 and 2, it is also possible to use fastening materials such as nails or parapets of a length that can penetrate from the outer surface 31 of the fire-resistant coating material 30 from the third layer onwards into the wooden beam 2 and fix it thereto, thereby making a wooden fire-resistant beam in which the fire-resistant coating materials 30, 30... that form three or more fire-resistant coating layers 3 from the first layer to the third layer onwards are fixed to the wooden beam 2.
In the case of the wooden fire-resistant beam of Comparative Example 3, it is expected that the falling off of the fire-resistant coating layer 3 arranged to cover the underside 22 of the wooden beam 2 can be suppressed compared to the wooden fire-resistant beams of Comparative Examples 1 and 2.
However, in the case of the wooden fire-resistant beam of Comparative Example 3, in the three-hour fire resistance test, the heads of the fastening materials such as nails and parapets that penetrate and fix the wooden beam 2 are positioned close to the fire source, so there is a high possibility that the part of the wooden beam 2 that comes into contact with the fastening materials will burn due to the thermal bridge phenomenon in which heat from the fire source is transferred to the inside of the wooden beam 2 through the fastening materials such as nails and parapets, and there is a high possibility that the three-hour fire resistance test will not be passed.

実施形態２及び比較例１乃至３で説明したような、８層の耐火被覆層３を備えた木質耐火梁においては、３時間耐火試験に合格するためには、以下の条件（１），（２）が必要であると考えられる。
（１）まず、木質梁２に貫入されて固定される留付材は、１層目の耐火被覆材３０を木質梁２に取付ける留付材及び２層目の耐火被覆材３０を木質梁２に取付ける留付材だけとして、かつ、当該留付材は、木質梁２に対する貫入長さが十分に確保される長さのものを用いること、及び、３層目以降の耐火被覆材３０を取付ける留付材は、木質梁２に到達しない長さの留付材を用いることにより、１層目と２層目の耐火被覆材３０，３０の落下を防止するとともに、熱橋の影響を排除すること。
（２）さらに、木質梁２の下面２２に設けられた３層目～８層目を形成する耐火被覆材３０，３０…の落下を防止するために、木質梁２の両方の側面２１，２１に設けられた耐火被覆層３を形成する４層目以降の耐火被覆材３０の外面３１及び木質梁の下面２２に設けられた耐火被覆層３を形成する４層目以降の耐火被覆材３０の外面３１に亘って連続するように面材５を設け、かつ、この面材５を、上述した接着剤６１と留付材６２とで構成された固定手段６を用いて、耐火被覆層３の４層目以降の耐火被覆材３０の外面３１に固定することにより、耐火被覆層３の１層目から４層目までの耐火被覆材３０，３０…の部分を吊る吊手段４を設けること。 In a wood fire-resistant beam having eight fire-resistant coating layers 3 as described in the second embodiment and comparative examples 1 to 3, it is considered that the following conditions (1) and (2) are necessary to pass a three-hour fire resistance test.
(1) First, the fastening materials that penetrate and fix the wooden beam 2 are limited to the fastening materials that attach the first layer of fire-resistant coating material 30 to the wooden beam 2 and the fastening materials that attach the second layer of fire-resistant coating material 30 to the wooden beam 2, and the fastening materials should be of a length that ensures a sufficient penetration length into the wooden beam 2. Furthermore, the fastening materials that attach the third and subsequent layers of fire-resistant coating material 30 should be of a length that does not reach the wooden beam 2, thereby preventing the first and second layers of fire-resistant coating materials 30, 30 from falling and eliminating the effects of thermal bridges.
(2) Furthermore, in order to prevent the third to eighth layers of fire-resistant coating materials 30, 30... provided on the underside 22 of the wooden beam 2 from falling off, a surface material 5 is provided so as to continue over the outer surface 31 of the fourth and subsequent layers of fire-resistant coating materials 30 that form the fire-resistant coating layer 3 provided on both side surfaces 21, 21 of the wooden beam 2 and the outer surface 31 of the fourth and subsequent layers of fire-resistant coating materials 30 that form the fire-resistant coating layer 3 provided on the underside 22 of the wooden beam, and this surface material 5 is fixed to the outer surface 31 of the fourth and subsequent layers of fire-resistant coating materials 30 of the fire-resistant coating layer 3 using the fixing means 6 composed of the above-mentioned adhesive 61 and fastening material 62, thereby providing a suspending means 4 for suspending the first to fourth layers of fire-resistant coating materials 30, 30... of the fire-resistant coating layer 3.

即ち、比較例１乃至比較例３で説明した８層構造の耐火被覆層３を備えた木質耐火梁と比べて、実施形態２の８層構造の耐火被覆層３を備えた木質耐火梁１によれば、吊手段４を備えたことにより、耐火被覆層３の１層目から４層目までの耐火被覆材３０，３０…の部分が吊られた状態となるため、木質梁２の下面２２に設けられた耐火被覆層３の自重の影響を小さくできて、木質梁２の下面２２を覆うように設けられた耐火被覆層３の落下を抑制できる。
つまり、比較例１の木質耐火梁では、木質梁２の下面２２に設けられた耐火被覆層３の自重が、８層分の耐火被覆材３０，３０…となり、また、比較例２の木質耐火梁では、木質梁２の下面２２に設けられた耐火被覆層３の自重が、６層分の耐火被覆材３０，３０…となるのに対して、実施形態２の木質耐火梁１によれば、木質梁２の下面２２に設けられた耐火被覆層３の自重が、４層分の耐火被覆材３０，３０…となるため、木質梁２の下面２２に設けられた耐火被覆層３の自重の影響を小さくできる。
また、８層構造の耐火被覆層３の３層目以降を形成する耐火被覆材の留付材として、木質梁２に貫入しないステープルを用いたので、木質梁２に対する熱橋現象も抑制できる。 In other words, compared to the wooden fire-resistant beams having a fire-resistant coating layer 3 with an eight-layer structure described in Comparative Examples 1 to 3, the wooden fire-resistant beam 1 having the fire-resistant coating layer 3 with an eight-layer structure of embodiment 2 is provided with the hanging means 4, so that the first to fourth layers of the fire-resistant coating material 30, 30... of the fire-resistant coating layer 3 are suspended, thereby reducing the effect of the weight of the fire-resistant coating layer 3 provided on the underside 22 of the wooden beam 2 and preventing the fire-resistant coating layer 3 provided to cover the underside 22 of the wooden beam 2 from falling.
In other words, in the wooden fire-resistant beam of Comparative Example 1, the weight of the fire-resistant coating layer 3 provided on the underside 22 of the wooden beam 2 is eight layers of fire-resistant coating material 30, 30..., and in the wooden fire-resistant beam of Comparative Example 2, the weight of the fire-resistant coating layer 3 provided on the underside 22 of the wooden beam 2 is six layers of fire-resistant coating material 30, 30..., whereas according to the wooden fire-resistant beam 1 of Embodiment 2, the weight of the fire-resistant coating layer 3 provided on the underside 22 of the wooden beam 2 is four layers of fire-resistant coating material 30, 30..., thereby reducing the impact of the weight of the fire-resistant coating layer 3 provided on the underside 22 of the wooden beam 2.
In addition, since staples that do not penetrate the wooden beams 2 are used as fastening materials for the fire-resistant coating material that forms the third layer and beyond of the eight-layer fire-resistant coating layer 3, the thermal bridging phenomenon with respect to the wooden beams 2 can also be suppressed.

従って、実施形態２によれば、木質梁２の下面２２を覆うように設けられた耐火被覆層３の落下を抑制できるとともに、木質梁２に対する熱橋現象も抑制でき、３時間耐火試験に合格できる８層構造の耐火被覆層３を備えた木質耐火梁１を提供できるようになった。 Therefore, according to the second embodiment, it is possible to prevent the fire-resistant coating layer 3 provided to cover the underside 22 of the wooden beam 2 from falling off, and also to prevent the thermal bridging phenomenon on the wooden beam 2, and it is now possible to provide a wooden fire-resistant beam 1 equipped with an eight-layer fire-resistant coating layer 3 that can pass a three-hour fire resistance test.

実施形態３
例えば、８層構造の耐火被覆層３を備えた構成において、吊手段４を、２層目と３層目との間、４層目と５層目との間、６層目と７層目との間に、それぞれ設けた構成の木質耐火梁１とした。
即ち、図３に示すように、８層構造の耐火被覆層３における２層目と３層目との間に第１の吊手段４を設け、４層目と３層目との間に第２の吊手段４を設け、６層目と７層目との間に第３の吊手段４を設けた構成とした。
尚、吊手段４の配置以外のその他の構成は、図２に示した実施形態２の構成と同じである。 EMBODIMENT 3
For example, in a configuration having an eight-layer fire-resistant coating layer 3, the wooden fire-resistant beam 1 has suspension means 4 provided between the second and third layers, between the fourth and fifth layers, and between the sixth and seventh layers, respectively.
That is, as shown in FIG. 3, a first suspension means 4 is provided between the second and third layers of the eight-layer fire-resistant coating layer 3, a second suspension means 4 is provided between the fourth and third layers, and a third suspension means 4 is provided between the sixth and seventh layers.
The configuration other than the arrangement of the hanging means 4 is the same as that of the second embodiment shown in FIG.

実施形態３に係る木質耐火梁１によれば、第１の吊手段４によって、耐火被覆層３の１層目及び２層目の耐火被覆材３０，３０の部分が吊られた状態となり、第２の吊手段４によって、耐火被覆層３の３層目及び４層目の耐火被覆材３０，３０の部分が吊られた状態となり、第３の吊手段４によって、耐火被覆層３の５層目及び６層目の耐火被覆材３０，３０の部分が吊られた状態となる。
従って、実施形態３に係る木質耐火梁１によれば、木質梁２の下面２２に設けられた耐火被覆層３の自重が、２層分の耐火被覆材３０，３０となるため、木質梁２の下面２２に設けられた耐火被覆層３の自重の影響を小さくできて、木質梁２の下面２２を覆うように設けられた耐火被覆層３の落下を、火災時などにおいてより効果的に抑制できるようになり、所期の耐火性能を十分に発揮できる木質耐火梁１を得ることができるようになった。
特に、２層分毎に、吊手段４を設けたので、１つ１つの吊手段４に加わる吊重量を小さくでき、耐火被覆層３の落下抑制効果がより向上する。 In the wood fire-resistant beam 1 of embodiment 3, the first hanging means 4 suspends the first and second layers of fire-resistant coating material 30, 30 of the fire-resistant coating layer 3, the second hanging means 4 suspends the third and fourth layers of fire-resistant coating material 30, 30 of the fire-resistant coating layer 3, and the third hanging means 4 suspends the fifth and sixth layers of fire-resistant coating material 30, 30 of the fire-resistant coating layer 3.
Therefore, according to the wooden fire-resistant beam 1 of embodiment 3, the weight of the fire-resistant coating layer 3 provided on the underside 22 of the wooden beam 2 is two layers of fire-resistant coating material 30, 30, so the effect of the weight of the fire-resistant coating layer 3 provided on the underside 22 of the wooden beam 2 can be reduced, and the falling of the fire-resistant coating layer 3 provided to cover the underside 22 of the wooden beam 2 can be more effectively suppressed in the event of a fire, etc., and it is possible to obtain a wooden fire-resistant beam 1 that can fully exhibit the desired fire resistance performance.
In particular, since the hanging means 4 is provided for every two layers, the hanging weight applied to each hanging means 4 can be reduced, and the effect of preventing the fire-resistant coating layer 3 from falling is further improved.

尚、実施形態２，３に係る木質耐火梁１では、最も外側に位置される耐火被覆材３０の外面を覆う図外の化粧材（表面材）を設けることが好ましいが、当該化粧材を設けないようにしてもよい。 In addition, in the wood fire-resistant beam 1 according to the second and third embodiments, it is preferable to provide a decorative material (surface material) not shown in the figure that covers the outer surface of the fire-resistant covering material 30 located on the outermost side, but it is also possible not to provide such a decorative material.

また、面材５としてのメッシュシートは、耐火被覆層３の外側の面全体に設けられることが好ましいが、木質梁２の延長方向（材軸方向）に沿って間欠的に設けるようにしてもよい。 The mesh sheet as the surface material 5 is preferably provided on the entire outer surface of the fire-resistant coating layer 3, but may be provided intermittently along the extension direction (material axis direction) of the wooden beam 2.

また、上記では、メッシュシートとして、ガラス繊維強化プラスチック（グラスファイバー）製のメッシュシートを用いた例を示したが、メッシュシートの材質は特に限定されず、例えば、金属製、その他の合成樹脂製等のメッシュシートを用いてもかまわない。 In the above, an example was given in which a mesh sheet made of glass fiber reinforced plastic (glass fiber) was used as the mesh sheet, but the material of the mesh sheet is not particularly limited, and for example, a mesh sheet made of metal or other synthetic resins may be used.

また、上記では、固定手段６が、面材５としてのメッシュシートを耐火被覆層３の外側の面に固定するための留付材６２と接着剤６１とで構成された例を示したが、一対の針部６３，３６間の所定の間隔ｂが、メッシュシートのメッシュの目開きの寸法ａよりも大きいステープルだけを用いて面材５としてのメッシュシートを耐火被覆層３の外側の面に固定するようにしても良い。
また、接着剤６１だけを用いて、メッシュシートのメッシュの開口５１を介して、メッシュシートと耐火被覆層３の外側の面との間、及び、メッシュシートの外側に行き渡るように接着剤６１を塗布することによって、メッシュシートを耐火被覆層３の外側の面に固定するようにしても良い。 In the above example, the fixing means 6 is composed of the fastening material 62 and the adhesive 61 for fixing the mesh sheet as the face material 5 to the outer surface of the fire-resistant coating layer 3. However, the mesh sheet as the face material 5 may be fixed to the outer surface of the fire-resistant coating layer 3 using only staples in which the predetermined distance b between a pair of needle portions 63, 36 is larger than the mesh opening dimension a of the mesh sheet.
Alternatively, the mesh sheet may be fixed to the outer surface of the fire-resistant coating layer 3 by applying only the adhesive 61 through the mesh openings 51 in the mesh sheet, between the mesh sheet and the outer surface of the fire-resistant coating layer 3, and over the outside of the mesh sheet.

面材５としては、薄厚（例えば厚さ１ｍｍ以下）の面シート（薄板材）を用いてもよい。また、当該面シートの材質は特に限定されず、例えば、金属製、その他の合成樹脂製等の面シートを用いてもかまわない。 The face material 5 may be a thin (e.g., 1 mm or less) face sheet (thin plate material). The material of the face sheet is not particularly limited, and face sheets made of, for example, metal or other synthetic resins may be used.

また、上記では、板状の耐火被覆材としてのせっこうボードと火山性ガラス質複層板とを用いて構成された８層の耐火被覆層を備えた木質耐火梁を例示したが、耐火被覆層を形成する耐火被覆材として、せっこうボードや火山性ガラス質複層板以外の耐火被覆材を用いてもかまわない。
また、耐火被覆層は、上述した１層や８層の耐火被覆層に限らず、８層以外の複数層の耐火被覆層であっても良く、層数に対応して、吊手段４を設ける位置を適宜選定すればよい。 In addition, in the above example, a wooden fire-resistant beam having eight fire-resistant layers composed of gypsum board and volcanic vitreous laminated board as plate-shaped fire-resistant coating materials was given as an example, but fire-resistant coating materials other than gypsum board and volcanic vitreous laminated board may also be used as the fire-resistant coating material that forms the fire-resistant coating layer.
Furthermore, the fire-resistant coating layer is not limited to the one-layer or eight-layer fire-resistant coating layer described above, but may be a fire-resistant coating layer with multiple layers other than eight layers, and the position at which the hanging means 4 is provided may be appropriately selected according to the number of layers.

尚、木質梁２の両方の側面２１，２１と下面２２とを覆うように設けられた耐火被覆層３が、複数層構造の耐火被覆層により構成された木質耐火梁１の場合は、実施形態２のように、いずれかの層間に１つだけ吊手段４を設けた構成よりも、実施形態３のように、いくつかの層間にそれぞれ個別に吊手段４，４…を設ける構成としたほうが、耐火被覆層３の落下抑制効果がより向上して、所期の耐火性能を十分に発揮できる木質耐火梁１を得ることができるようになるので、好ましい。 In the case of a fire-resistant wooden beam 1 in which the fire-resistant coating layer 3 provided to cover both side surfaces 21, 21 and the underside 22 of the wooden beam 2 is composed of a fire-resistant coating layer having a multi-layer structure, it is preferable to provide individual hanging means 4, 4... between several layers as in embodiment 3, rather than providing only one hanging means 4 between any of the layers as in embodiment 2, because this improves the effect of preventing the fire-resistant coating layer 3 from falling, and makes it possible to obtain a fire-resistant wooden beam 1 that can fully exhibit the desired fire resistance performance.

本発明の木質耐火梁１によれば、木質梁１の下面２２を覆うように設けられた耐火被覆層３の落下を抑制する吊手段４を備えており、少なくとも、当該吊手段４で吊られた耐火被覆層３の落下を抑制できるようになることから、吊手段４を備えない従来の木質耐火梁と比べた場合に、耐火被覆層３の落下を抑制できて所期の耐火性能を発揮できる木質耐火梁１を提供できるようになった。 The wooden fire-resistant beam 1 of the present invention is provided with a hanging means 4 that prevents the fire-resistant coating layer 3, which is provided to cover the underside 22 of the wooden beam 1, from falling. This makes it possible to prevent at least the fire-resistant coating layer 3 suspended by the hanging means 4 from falling. This makes it possible to provide a wooden fire-resistant beam 1 that can prevent the fire-resistant coating layer 3 from falling and exhibit the desired fire resistance performance, compared to a conventional wooden fire-resistant beam that does not have a hanging means 4.

１木質耐火梁、２木質梁、３耐火被覆層、４吊手段、５面材、
６固定手段、２１，２１木質梁の両方の側面、２２木質梁の下面、
３０耐火被覆材、５１メッシュの開口、５２メッシュシートの線材、
６１接着剤、６２留付材、６３ステープルの針部、
６４ステープルの針頭部、ａメッシュシートのメッシュの目開きの寸法、
ｂステープルの一対の針部間の所定の間隔。 Reference Signs List 1 Wood fireproof beam, 2 Wood beam, 3 Fireproof coating layer, 4 Suspension means, 5 Face material,
6 fixing means, 21, 21 both side surfaces of wooden beam, 22 underside of wooden beam,
30 fireproof coating material, 51 mesh opening, 52 mesh sheet wire,
61 adhesive, 62 fastening material, 63 staple portion,
64: staple head; a: mesh opening size of mesh sheet;
b) a predetermined distance between a pair of staples.

Claims

A fire-resistant wooden beam having a wooden beam and a fire-resistant coating layer provided so as to cover both sides and a bottom surface of the wooden beam,
A hanging means is provided to prevent the fireproof coating layer provided to cover the underside of the wooden beam from falling off,
The suspension means is
A mesh sheet is provided so as to be continuous across the outer surfaces of the fire-resistant coating material forming the fire-resistant coating layer provided on both side surfaces of the wooden beam and the outer surfaces of the fire-resistant coating material forming the fire-resistant coating layer provided on the underside of the wooden beam;
and a fixing means for fixing the mesh sheet to an outer surface of the fire-resistant covering material that forms the fire-resistant covering layer ,
The fire-resistant coating layer is formed by laminating two or more layers of plate-shaped fire-resistant coating materials,
The mesh sheet is provided along the outer surface of the fire-resistant coating material that forms any layer other than the outermost layer of the fire-resistant coating layer;
The fixing means is an adhesive and a fastener.
The adhesive is applied between the mesh sheet and the outer surface of the fire-resistant coating layer through the mesh openings of the mesh sheet, and to the outside of the mesh sheet;
The fastening material is a staple having a pair of needle portions arranged in parallel with a predetermined distance therebetween and a needle head portion connecting one ends of the pair of needle portions to each other,
The staple is a wooden fire-resistant beam characterized in that the predetermined distance between a pair of needle portions is larger than the size of the mesh opening of the mesh sheet .

A wooden fire-resistant beam as claimed in claim 1, characterized in that the staples which penetrate and fix the wooden beam are only the staples which attach the first layer of fire-resistant covering material to the wooden beam and the staples which attach the second layer of fire-resistant covering material to the wooden beam, and the staples which attach the third layer and subsequent layers of fire-resistant covering material are of a length which does not reach the wooden beam .

3. A wooden fire-resistant beam according to claim 1 or 2, characterized in that a mesh sheet is provided on the outer surface of the fourth or subsequent layers of fire-resistant coating material .

A wooden fire-resistant beam as claimed in claim 1 or 2, characterized in that the suspension means are provided between the second and third layers of fire-resistant covering material, between the fourth and fifth layers of fire-resistant covering material, and between the sixth and seventh layers of fire-resistant covering material .

The wooden fire- resistant beam according to any one of claims 1 to 4, characterized in that the fire-resistant coating layer is composed of an eight-layer fire-resistant coating layer formed by stacking eight sheets of fire-resistant coating material .