JP7363664B2 - Fireproof coating structure and its design method - Google Patents
Fireproof coating structure and its design method Download PDFInfo
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Description
本発明は、鋼構造物を構成する鋼部材の耐火被覆構造であって、特に鋼部材を覆うように配置された耐火被覆材と該耐火被覆材の外側に設けられた木質材とを備えて構成される耐火被覆構造、およびその設計方法に関する。 The present invention is a fireproof coating structure for steel members constituting a steel structure, and particularly includes a fireproof coating disposed to cover the steel member and a wood material provided outside the fireproof coating. The present invention relates to a fireproof covering structure constructed and a method for designing the same.
建築物では火災による倒壊及び延焼を防止するために主要構造部に耐火性能が要求され、鋼構造建物で鋼材が火災で高温になると強度が低下し倒壊の恐れがあるため耐火被覆がなされる。
耐火被覆材には不燃材が用いられ、その種類は吹付けロックウール、強化石膏ボード、けい酸カルシウム板、耐火塗料等多種多様である。
耐火被覆材にはそれぞれ特徴があり、吹付けロックウールはロックウール粒状綿を主原料とし、硬化材としてのセメント、水からなり、これらの混合物を現場で鉄骨構造体に専用の吹付け機で吹き付ける耐火被覆材であり、他の耐火被覆材に比べて安価であるが化粧材を別途設けたり、現場の養生、硬化の待機等で時間がかかる。
In buildings, fire-resistant performance is required for the main structural parts to prevent collapse and spread of fire.In steel structures, if the steel material becomes hot in a fire, its strength will decrease and there is a risk of collapse, so a fire-resistant coating is applied.
Noncombustible materials are used for fireproof covering materials, and there are a wide variety of types, including sprayed rock wool, reinforced gypsum board, calcium silicate board, and fireproof paint.
Each fireproof covering material has its own characteristics. Sprayed rockwool is made of rockwool granular cotton as the main raw material, cement as a hardening agent, and water. A mixture of these is sprayed onto steel structures on site using a special spraying machine. It is a spray-on fireproof coating, and although it is cheaper than other fireproof coatings, it takes time due to the separate installation of decorative materials, on-site curing, and waiting for curing.
強化石膏ボードやけい酸カルシウム板は意匠性もあるため化粧材を不要にできたり、耐火被覆材と鋼部材の間に隙間を設ける浮かし張りが可能であったりするものの、吹付けロックウールに比べると高価である。
また、浮かし張りの場合、耐火被覆材と鋼部材の間の隙間の大きさによって耐火性能が変わり、耐火被覆材と鋼部材の間に隙間を設けない直張りと比べて、耐火性能が優れる場合も劣る場合もある。
Reinforced gypsum board and calcium silicate board have a good design, making it possible to eliminate the need for decorative materials, and to create a gap between the fireproof coating and steel components, but they are not as effective as spray-on rock wool. and expensive.
In addition, in the case of floating cladding, the fire resistance performance changes depending on the size of the gap between the fireproof sheathing and the steel member, and the fire resistance performance may be superior to that of direct cladding, where there is no gap between the fireproof sheathing and the steel member. may also be inferior.
ところで、昨今CO2排出問題から木材の利用が推進されている。木材は建築物において構造材料として用いられるほかに、意匠性に優れていることから化粧材としても用いられる。木材は火災時に焼失するものの、焼失前に炭化し断熱性能を発揮する。このため、意匠材兼耐火被覆材としての利用が期待されているが、木材単体で長時間耐火性能を期待することは難しい。 By the way, the use of wood has recently been promoted due to the problem of CO 2 emissions. In addition to being used as a structural material in buildings, wood is also used as a decorative material due to its excellent design. Wood burns down in the event of a fire, but before it burns down, it chars and provides insulation. For this reason, it is expected to be used as both a decorative material and a fire-resistant covering material, but it is difficult to expect long-term fire resistance from wood alone.
特許文献１では、木材による構造材に対し、不燃材からなる燃え止まり層と、所定の厚さの木材からなる燃えしろ層、外側に配置した耐火構造材を提案している。 Patent Document 1 proposes, for a structural material made of wood, a fireproofing layer made of a noncombustible material, a burning layer made of wood having a predetermined thickness, and a fireproof structural material disposed on the outside.
また、特許文献２では、鋼部材に対し、耐火被覆材と、耐火被覆材の表面に化粧材として設けられる木質材の断熱性能を考慮して、耐火被覆材の厚さを従来より薄くできる耐火被覆構造が提案されている。 In addition, Patent Document 2 discloses a fireproof coating for steel members that allows the thickness of the fireproof coating to be made thinner than before, taking into account the heat insulation performance of the fireproof coating and the wood material provided as a decorative material on the surface of the fireproof coating. A covering structure has been proposed.
前述の通り、木材の利用が推進されている中、木材を化粧材兼耐火被覆材として利用する工法が提案されている。
しかし、木材単体で十分な耐火性能を得ることが難しいことから、特許文献１、２に示されるように、不燃材や従来の耐火被覆材を併用した耐火被覆構造が提案されている。
As mentioned above, while the use of wood is being promoted, construction methods have been proposed that use wood as both a decorative material and a fireproof covering material.
However, since it is difficult to obtain sufficient fireproof performance with wood alone, fireproof coating structures using a combination of noncombustible materials and conventional fireproof coating materials have been proposed, as shown in Patent Documents 1 and 2.
特許文献１によれば、木材と不燃材を組み合わせることで耐火被覆としての性能が得られることが示唆されている。
しかしながら、特許文献１は耐火構造材を提案するものであり、要求耐火時間の規定のある鋼部材の被覆構造ではない。
この点、特許文献２では、鋼部材の要求耐火時間との関係で、木質材の必要厚さを数式で規定している。
According to Patent Document 1, it is suggested that performance as a fireproof coating can be obtained by combining wood and noncombustible materials.
However, Patent Document 1 proposes a fire-resistant structural material, and is not a covering structure for steel members with a prescribed fire-resistant time.
In this regard, in Patent Document 2, the required thickness of the wood material is defined by a mathematical formula in relation to the required fire resistance time of the steel member.
鋼部材を被覆材で被覆する場合、必要とされる被覆厚さは鋼部材のサイズによっても異なり、鋼部材が厚いほど必要な被覆厚さは小さくなる。もちろん被覆材料の熱物性値、密度、水分量などの影響もある。このように、耐火性能は材料特性、被覆材の厚さ、鋼部材のサイズなど多様なパラメータの影響を受ける。
しかし、特許文献２では、鋼部材の形状、耐火被覆材の厚さ等、木材の厚さと要求耐火時間以外のパラメータが全て定数化されており、鋼部材のサイズや耐火被覆材の厚さなどの多様な仕様に十分対応できないという課題がある。
When covering a steel member with a coating material, the required coating thickness varies depending on the size of the steel member, and the thicker the steel member, the smaller the required coating thickness. Of course, there are also influences such as the thermophysical properties, density, and moisture content of the coating material. Thus, fire resistance performance is influenced by various parameters such as material properties, cladding thickness, and steel member size.
However, in Patent Document 2, all parameters other than the thickness of the wood and the required fire resistance time, such as the shape of the steel member and the thickness of the fireproof coating, are constants, and the size of the steel member, the thickness of the fireproof coating, etc. The problem is that it cannot adequately accommodate the diverse specifications of
本発明はかかる課題を解決するためになされたものであり、被覆対象となる鋼部材のサイズや、必要な耐火時間に応じて、耐火被覆材の厚さや木材の厚さが合理的に設定され、多様な仕様に対応した耐火被覆構造、該耐火被覆構造の設計方法を提供することを目的としている。 The present invention was made to solve this problem, and the thickness of the fireproof coating material and the thickness of the wood can be set rationally according to the size of the steel member to be coated and the required fire resistance time. The purpose of the present invention is to provide a fireproof coating structure that can meet various specifications, and a method for designing the fireproof coating structure.
（１）本発明に係る耐火被覆構造は、鋼構造物を構成する鋼部材の表面に接するよう配置されて前記鋼部材を覆う耐火被覆材と、該耐火被覆材の外側に設けられた木質材とを備えた耐火被覆構造であって、下式を満たすことを特徴とするものである。
T≦TA+TB
TA=O×(tA×As/Hs)P+10
TB=X×(tB/VB)Y
ただし、T：要求耐火時間(min)
TA：耐火被覆材を鋼部材に接するように設けた場合の耐火時間(min)
TB：木質材による耐火時間(min)
tA：耐火被覆材の厚さ(mm)
As：鋼部材の断面積(mm2)
Hs：鋼部材表面の周長(mm)
O，P：耐火被覆材の熱物性値、密度等から決まる定数
tB：木質材の厚さ(mm)
VB：火災加熱時の木質材の炭化速度(mm/min)
X,Y：木質材の熱物性値，密度等から決まる定数
(1) The fire-resistant covering structure according to the present invention includes a fire-resistant covering material disposed in contact with the surface of a steel member constituting a steel structure and covering the steel member, and a wooden material provided outside the fire-resistant covering material. This is a fireproof coating structure having the following features:
T≦T A +T B
T A =O×(t A ×A s /H s ) P +10
T B =X×(t B /V B ) Y
However, T: Required fire resistance time (min)
T A : Fire resistance time (min) when fireproof coating is installed in contact with steel members
T B : Fire resistance time (min) of wood materials
t A : Thickness of fireproof coating material (mm)
A s : Cross-sectional area of steel member (mm 2 )
H s : Perimeter of steel member surface (mm)
O, P: Constants determined from the thermal properties, density, etc. of the fireproof coating material
t B : Thickness of wood material (mm)
V B : Carbonization rate of wood material during fire heating (mm/min)
X,Y: Constants determined from the thermophysical properties of wood, density, etc.
（２）また、鋼構造物を構成する鋼部材の表面から離隔するように配置され、前記鋼部材を覆う耐火被覆材と、該耐火被覆材の外側に設けられた木質材とを備えた耐火被覆構造であって、下式を満たすことを特徴とするものである。
T≦TA×α+TB
TA=O×(tA×As/Hs)P+10
α＝Q+R×(Hr/Hs)S
TB=X×(tB/VB)Y
ただし、T：要求耐火時間(min)
TA：耐火被覆材を鋼部材に接するように設けた場合の耐火時間(min)
α：耐火被覆材の設置位置による係数
TB：木質材による耐火時間(min)
tA：耐火被覆材の厚さ(mm)
As：鋼部材の断面積(mm2)
Hs：鋼部材表面の周長(mm)
O，P：耐火被覆材の熱物性値、密度等から決まる定数
Hr：耐火被覆材内面の周長(mm)
Q,R,S：鋼部材断面による定数
tB：木質材の厚さ(mm)
VB：火災加熱時の木質材の炭化速度(mm/min)
X,Y：木質材の熱物性値，密度等から決まる定数
(2) Also, a fireproofing device comprising a fireproofing material arranged so as to be spaced apart from the surface of a steel member constituting a steel structure and covering the steel member, and a wood material provided outside the fireproofing material. It is a covering structure, and is characterized by satisfying the following formula.
T≦T A ×α+T B
T A =O×(t A ×A s /H s ) P +10
α＝Q+R×(H r /H s ) S
T B =X×(t B /V B ) Y
However, T: Required fire resistance time (min)
T A : Fire resistance time (min) when fireproof coating is installed in contact with steel members
α: Coefficient depending on the installation position of fireproof covering material
T B : Fire resistance time (min) of wood materials
t A : Thickness of fireproof coating material (mm)
A s : Cross-sectional area of steel member (mm 2 )
H s : Perimeter of steel member surface (mm)
O, P: Constants determined from the thermal properties, density, etc. of the fireproof coating material
H r : Circumference of inner surface of fireproof coating (mm)
Q,R,S: Constants depending on the steel member cross section
t B : Thickness of wood material (mm)
V B : Carbonization rate of wood material during fire heating (mm/min)
X,Y: Constants determined from the thermophysical properties of wood, density, etc.
（３）また、上記（１）又は（２）に記載のものにおいて、前記鋼部材が箱形断面の柱であり、前記耐火被覆材の厚さ、もしくは密度が、耐火被覆材単独で前記鋼部材を被覆する場合に必要とされる厚さ、もしくは密度よりも、薄いもしくは小さいことを特徴とするものである。 (3) Further, in the item described in (1) or (2) above, the steel member is a column with a box-shaped cross section, and the thickness or density of the fireproof coating is different from that of the fireproof coating alone. It is characterized by being thinner or smaller than the thickness or density required for covering the member.
（４）また、上記（１）乃至（３）のいずれかに記載のものにおいて、前記耐火被覆材が吹付けロックウールであり、
前記木質材が、前記鋼部材の表面もしくは前記耐火被覆材の表面に設置された不燃材からなるスペーサーによって、前記鋼部材の表面から前記吹付けロックウールの必要厚さ以上の隙間を介して設置され、前記吹付けロックウールが前記隙間に設けられていることを特徴とするものである。
(4) Furthermore, in the product according to any one of (1) to (3) above, the fireproof covering material is sprayed rock wool,
The wooden material is installed from the surface of the steel member through a gap equal to or greater than the required thickness of the sprayed rock wool by a spacer made of a noncombustible material installed on the surface of the steel member or the surface of the fireproof coating material. and the sprayed rock wool is provided in the gap.
（５）本発明に係る耐火被覆構造の設計方法は、鋼構造物を構成する鋼部材の表面に接するよう配置されて前記鋼部材を覆う耐火被覆材と、該耐火被覆材の外側に設けられた木質材とを備えた耐火被覆構造の設計方法であって、下式を満たすように設計することを特徴とするものである。
T≦TA+TB
TA=O×(tA×As/Hs)P+10
TB=X×(tB/VB)Y
ただし、T：要求耐火時間(min)
TA：耐火被覆材を鋼部材に接するように設けた場合の耐火時間(min)
TB：木質材による耐火時間(min)
tA：耐火被覆材の厚さ(mm)
As：鋼部材の断面積(mm2)
Hs：鋼部材表面の周長(mm)
O，P：耐火被覆材の熱物性値、密度等から決まる定数
tB：木質材の厚さ(mm)
VB：火災加熱時の木質材の炭化速度(mm/min)
X,Y：木質材の熱物性値，密度等から決まる定数
(5) The method for designing a fire-resistant sheathing structure according to the present invention includes a fire-resistant sheathing material disposed so as to be in contact with the surface of a steel member constituting a steel structure and covering said steel member; This is a method for designing a fireproof covering structure equipped with a wooden material, characterized by designing the structure so as to satisfy the following formula.
T≦T A +T B
T A =O×(t A ×A s /H s ) P +10
T B =X×(t B /V B ) Y
However, T: Required fire resistance time (min)
T A : Fire resistance time (min) when fireproof coating is installed in contact with steel members
T B : Fire resistance time (min) of wood materials
t A : Thickness of fireproof coating material (mm)
A s : Cross-sectional area of steel member (mm 2 )
H s : Perimeter of steel member surface (mm)
O, P: Constants determined from the thermal properties, density, etc. of the fireproof coating material
t B : Thickness of wood material (mm)
V B : Carbonization rate of wood material during fire heating (mm/min)
X,Y: Constants determined from the thermophysical properties of wood, density, etc.
（６）また、鋼構造物を構成する鋼部材の表面から離隔するように配置され、前記鋼部材を覆う耐火被覆材と、該耐火被覆材の外側に設けられた木質材とを備えた耐火被覆構造の設計方法であって、下式を満たすように設計することを特徴とするものである。
T≦TA+TB
TA=O×(tA×As/Hs)P+10
α＝Q+R×(Hr/Hs)S
TB=X×(tB/VB)Y
ただし、T：要求耐火時間(min)
TA：耐火被覆材を鋼部材に接するように設けた場合の耐火時間(min)
α：耐火被覆材の設置位置による係数
TB：木質材による耐火時間(min)
tA：耐火被覆材の厚さ(mm)
As：鋼部材の断面積(mm2)
Hs：鋼部材表面の周長(mm)
O，P：耐火被覆材の熱物性値、密度等から決まる定数
Hr：耐火被覆材内面の周長(mm)
Q,R,S：鋼部材断面による定数
tB：木質材の厚さ(mm)
VB：火災加熱時の木質材の炭化速度(mm/min)
X,Y：木質材の熱物性値，密度等から決まる定数
(6) Also, a fireproofing device comprising a fireproof covering material disposed so as to be spaced apart from the surface of a steel member constituting a steel structure and covering the steel member, and a wood material provided outside the fireproof covering material. This is a method of designing a covering structure, and is characterized by designing the covering structure so as to satisfy the following formula.
T≦T A +T B
T A =O×(t A ×A s /H s ) P +10
α＝Q+R×(H r /H s ) S
T B =X×(t B /V B ) Y
However, T: Required fire resistance time (min)
T A : Fire resistance time (min) when fireproof coating is installed in contact with steel members
α: Coefficient depending on the installation position of fireproof covering material
T B : Fire resistance time (min) of wood materials
t A : Thickness of fireproof coating material (mm)
A s : Cross-sectional area of steel member (mm 2 )
H s : Perimeter of steel member surface (mm)
O, P: Constants determined from the thermal properties, density, etc. of the fireproof coating material
H r : Circumference of inner surface of fireproof coating (mm)
Q,R,S: Constants depending on the steel member cross section
t B : Thickness of wood material (mm)
V B : Carbonization rate of wood material during fire heating (mm/min)
X,Y: Constants determined from the thermophysical properties of wood, density, etc.
本発明に係る耐火被覆構造は、鋼構造物を構成する鋼部材の表面に接するよう配置されて前記鋼部材を覆う耐火被覆材と、該耐火被覆材の外側に設けられた木質材とを備えた耐火被覆構造であって、所定の数式を満たすことにより、被覆対象となる鋼部材のサイズや、必要な耐火時間に応じた合理的な構造になっている。
また、本発明に係る耐火被覆構造の設計方法によれば、被覆対象となる鋼部材のサイズや、必要な耐火時間等の多様な仕様に対応した合理的な耐火被覆構造の設計が可能である。
A fire-resistant covering structure according to the present invention includes a fire-resistant covering material disposed in contact with the surface of a steel member constituting a steel structure and covering the steel member, and a wood material provided outside the fire-resistant covering material. By satisfying a predetermined mathematical formula, it has a rational structure that corresponds to the size of the steel member to be coated and the required fire resistance time.
Furthermore, according to the method for designing a fireproof coating structure according to the present invention, it is possible to design a rational fireproof coating structure that corresponds to various specifications such as the size of the steel member to be coated and the required fire resistance time. .
［実施の形態１］
本発明の一実施の形態に係る耐火被覆構造１は、図１、２に示すように、鋼構造物を構成する角形鋼管からなる鋼部材３の表面に接するよう配置されて鋼部材３を覆う耐火被覆材５と、耐火被覆材５の外側に設けられた木質材７とを備えたものであって、下記式(1)を満たすことを特徴とするものである。
T≦TA+TB ・・・(1)
TA=O×(tA×As/Hs)P+10
TB=X×(tB/VB)Y
ただし、T：要求耐火時間(min)
TA：耐火被覆材を鋼部材に接するように設けた場合の耐火時間(min)
TB：木質材による耐火時間(min)
tA：耐火被覆材の厚さ(mm)
As：鋼部材の断面積(mm2)
Hs：鋼部材表面の周長(mm)
O，P：耐火被覆材の熱物性値、密度等から決まる定数
tB：木質材の厚さ(mm)
VB：火災加熱時の木質材の炭化速度(mm/min)
X,Y：木質材の熱物性値，密度等から決まる定数
以下、各構成を詳細に説明する。
[Embodiment 1]
As shown in FIGS. 1 and 2, a fireproof covering structure 1 according to an embodiment of the present invention is arranged so as to be in contact with the surface of a steel member 3 made of a square steel pipe that constitutes a steel structure, and covers the steel member 3. It comprises a fireproof covering material 5 and a wooden material 7 provided outside the fireproof covering material 5, and is characterized by satisfying the following formula (1).
T≦T A +T B・・・(1)
T A =O×(t A ×A s /H s ) P +10
T B =X×(t B /V B ) Y
However, T: Required fire resistance time (min)
T A : Fire resistance time (min) when fireproof coating is installed in contact with steel members
T B : Fire resistance time (min) of wood materials
t A : Thickness of fireproof coating material (mm)
A s : Cross-sectional area of steel member (mm 2 )
H s : Perimeter of steel member surface (mm)
O, P: Constants determined from the thermal properties, density, etc. of the fireproof coating material
t B : Thickness of wood material (mm)
V B : Carbonization rate of wood material during fire heating (mm/min)
X, Y: Constants determined from the thermophysical properties, density, etc. of the wood material Each configuration will be explained in detail below.
＜鋼部材＞
鋼部材３は鋼構造物を構成する部材であって被覆対象となるものであり、たとえば鋼管柱や鋼製梁等のように要求耐火時間の規定がある部材である。
<Steel parts>
The steel member 3 is a member constituting a steel structure and is to be coated, and is a member such as a steel pipe column or a steel beam that has a prescribed fire resistance time.
＜耐火被覆材＞
耐火被覆材５は、鋼部材３の外周部に鋼部材３が要求耐火時間を満たすようにするために被覆する部材であり、本実施の形態は鋼部材３の表面に接するように配置されたいわゆる直張り形式である。
耐火被覆材５は、図１に示す吹付けロックウールやロックウールフェルト、図２に示すようなけい酸カルシウム板や強化石膏ボード等の板状の耐火被覆材、耐熱性ロックウールフェルトが挙げられる。
<Fireproof covering material>
The fireproof coating material 5 is a member that covers the outer circumference of the steel member 3 so that the steel member 3 satisfies the required fire resistance time, and in this embodiment, the fireproof coating material 5 is arranged so as to be in contact with the surface of the steel member 3. This is the so-called direct tension type.
Examples of the fire-resistant covering material 5 include sprayed rock wool and rock wool felt shown in FIG. 1, plate-shaped fire-resistant covering materials such as calcium silicate board and reinforced gypsum board shown in FIG. 2, and heat-resistant rock wool felt. .
＜木質材＞
木質材７は、耐火被覆材５の外側に設けられており、角部が釘やビス等の固定具９によって、耐火被覆材５、もしくは耐火被覆材５と木質材７の間に下地材として設けられる不燃部材に固定されている。
木質材７は、通常の木板だけでなく、CLT（Cross Laminated Timber）、集成材、合板、LVL（Laminated Veneer Lumber）といった単板やひき板による積層材も挙げられる。また角部だけでなく、板の中央付近でも耐火被覆材５もしくは下地材として設けられる不燃部材と木質材７を接合するようにしてもよく、このようにすれば、木質材７の反りなどの変形が抑えられる。
<Wood material>
The wooden material 7 is provided on the outside of the fireproof sheathing material 5, and its corner portions are attached to the fireproof sheathing material 5 or between the fireproof sheathing material 5 and the wood material 7 as a base material using fixing tools 9 such as nails or screws. It is fixed to the provided noncombustible member.
The wood material 7 includes not only ordinary wood boards but also laminated materials such as veneer and sawn boards such as CLT (Cross Laminated Timber), laminated wood, plywood, and LVL (Laminated Veneer Lumber). In addition, the wood material 7 may be joined to the fireproof covering material 5 or a noncombustible material provided as a base material not only at the corners but also near the center of the board. Deformation is suppressed.
＜式(1)＞
本実施の形態の耐火被覆構造１は、被覆対象である鋼部材３の外側に耐火被覆材５を配し、さらにその耐火被覆材５の外側に木質材７を配したものであり、鋼部材３のサイズ、耐火被覆材５の厚さ、木質材７の厚さなどから計算される予想耐火時間(TA+TB)が、鋼部材３の要求耐火時間Tを満足するように、耐火被覆材５の厚さ、木質材７の厚さが調整されており、この調整を行うための数式が式(1)である。
<Formula (1)>
The fireproof covering structure 1 of the present embodiment has a fireproof covering material 5 disposed on the outside of a steel member 3 to be covered, and a wood material 7 further disposed on the outside of the fireproof covering material 5. 3, the thickness of the fireproof covering material 5, the thickness of the wood material 7, etc., so that the expected fireproof time (T A +T B ) satisfies the required fireproof time T of the steel member 3. The thickness of the covering material 5 and the thickness of the wood material 7 are adjusted, and the formula for making this adjustment is Equation (1).
前述のように耐火性能は材料特性、被覆材の厚さ、直張り形式か浮かし張り形式といった張り形式、鋼部材３のサイズなど様々なパラメータの影響を受ける。この中で、比熱や熱伝導率等の材料の熱特性については、温度依存性が強いため、一義的に決定することは難しい。
そこで、本実施の形態では、直張り形式について、上記以外の形状に関するパラメータと、木質材７の板厚方向炭化速度の影響について考慮できるようにするために式(1)を規定した。
As mentioned above, the fire resistance performance is influenced by various parameters such as material properties, the thickness of the covering material, the tension type such as a straight tension type or a floating tension type, and the size of the steel member 3. Among these, it is difficult to unambiguously determine the thermal properties of materials such as specific heat and thermal conductivity because they are strongly temperature dependent.
Therefore, in the present embodiment, for the straight-strung type, Equation (1) is defined in order to be able to take into account parameters related to the shape other than those mentioned above and the influence of the carbonization rate in the thickness direction of the wood material 7.
上記の式(1)の導出根拠を以下に説明する。
まず、耐火被覆材単体を、直張り形式すなわち鋼部材３に接した状態で被覆した場合の耐火時間を予測するために、熱伝導計算による検討を行った。
被覆対象とした鋼部材３は□300x12（角形鋼管、幅，高さ=300mm、板厚=12mm、以下同じ。）、□300x16、□300x19、□300x22、□400x16、□500x16の６断面の角形鋼管とし、耐火被覆材５は吹付けロックウールとけい酸カルシウム板の２種類とし、被覆厚5～30mmの範囲で検討した。
The basis for deriving the above equation (1) will be explained below.
First, in order to predict the fire resistance time when a single fireproof coating material is coated in a straight-strung format, that is, in a state in which it is in contact with the steel member 3, a study was conducted using heat conduction calculations.
The steel member 3 to be coated is a rectangular shape with six cross sections: □300x12 (square steel pipe, width, height = 300 mm, plate thickness = 12 mm, the same applies hereinafter), □300x16, □300x19, □300x22, □400x16, □500x16. The steel pipe was used, and two types of fireproof coating material 5 were used: sprayed rock wool and calcium silicate plate, and the coating thickness was examined in the range of 5 to 30 mm.
吹付けロックウールは密度0.28g/cm3、含水率3%、けい酸カルシウム板は密度0.35g/cm3、含水率0%とした。
加熱温度はISO 834に規定される標準加熱温度曲線に準じ、鋼材温度が500℃に到達するまでの時間について検討した。図３に計算結果を示す。
図３の縦軸は耐火時間(min)で、横軸は被覆材の厚さtA(mm)である。図３に示すように、耐火時間(min)と耐火被覆材５の厚さtA(mm)との間には相関があることが分かる。
The sprayed rock wool had a density of 0.28 g/cm 3 and a water content of 3%, and the calcium silicate plate had a density of 0.35 g/cm 3 and a water content of 0%.
The heating temperature was determined according to the standard heating temperature curve specified in ISO 834, and the time required for the steel material temperature to reach 500°C was investigated. Figure 3 shows the calculation results.
The vertical axis of FIG. 3 is the fire resistance time (min), and the horizontal axis is the thickness t A (mm) of the coating material. As shown in FIG. 3, it can be seen that there is a correlation between the fireproof time (min) and the thickness t A (mm) of the fireproof coating 5.
そこで、耐火被覆材５の種類に共通する相関について検討したところ、図４に示すように、縦軸を耐火時間(min)とし、横軸を「被覆材の厚さtA(mm)」と「鋼部材の断面積Asを周長Hsで除した板厚相当値」との積(tA×As/Hs)とすることで、鋼部材３の大きさによらず一定の相関があることが分かった。
そして、両者の相関は、例えば吹付けロックウールとけい酸カルシウム板の場合でそれぞれ下記に示す式によって回帰でき、この回帰式によって耐火時間を精度予測できる。
吹付けロックウールの場合：TA=0.8291×(tA×As/Hs)0.8165+10
けい酸カルシウム板の場合：TA=0.925×(tA×As/Hs)0.8376+10
Therefore, we investigated the common correlation among the types of fireproof coating materials 5, and found that the vertical axis is the fire resistance time (min) and the horizontal axis is the "covering material thickness t A (mm)", as shown in Figure 4. By setting it as the product of "the plate thickness equivalent value obtained by dividing the cross-sectional area A s of the steel member by the circumference H s " (t A × A s /H s ), it is constant regardless of the size of the steel member 3. It turns out that there is a correlation.
The correlation between the two can be regressed using the following equations in the case of sprayed rock wool and calcium silicate plates, respectively, and the fire resistance time can be accurately predicted using this regression equation.
For sprayed rock wool: T A =0.8291×(t A ×A s /H s ) 0.8165 +10
For calcium silicate board: T A =0.925×(t A ×A s /H s ) 0.8376 +10
(tA×As/Hs)に係る係数は耐火被覆材５の熱物性値、密度、水分量などによって変化する。
また、鋼部材３が角形断面かH形断面かによっても変化する。
したがって、耐火被覆材５を鋼部材に接するように設けた場合の耐火時間TA(min)は下式によって求めることができる。
TA=O×(tA×As/Hs)P+10 ・・・(2)
ただし、O，P：耐火被覆材の熱物性値、密度等から決まる定数
The coefficient related to (t A ×A s /H s ) changes depending on the thermophysical property value, density, moisture content, etc. of the fireproof covering material 5.
It also changes depending on whether the steel member 3 has a square cross section or an H-shaped cross section.
Therefore, the fireproof time T A (min) when the fireproof covering material 5 is provided in contact with a steel member can be determined by the following formula.
T A =O×(t A ×A s /H s ) P +10 ・・・(2)
However, O, P: Constants determined from the thermophysical property values, density, etc. of the fireproof coating material.
次に木質材７を設けることによる耐火時間の増加量について検討した。
前述のように、同じ要求耐火時間に対しては、木質材７を設けることによって耐火被覆材単体で使用する場合よりも、耐火被覆材５の厚さを薄くすることが可能となる。そこで、木質材７を設けることによる耐火時間の増加量を求めるために木質材７の厚さをパラメータとした熱伝導計算を実施した。
Next, the amount of increase in fire resistance time due to the provision of the wood material 7 was examined.
As mentioned above, for the same required fire resistance time, by providing the wood material 7, it is possible to make the thickness of the fireproof covering material 5 thinner than when using the fireproof covering material alone. Therefore, in order to determine the amount of increase in fire resistance time due to the provision of the wood material 7, a heat conduction calculation was performed using the thickness of the wood material 7 as a parameter.
被覆対象の鋼部材３は□300x16の角形鋼管、耐火被覆材５は厚さ15mmのけい酸カルシウム板とし、木質材７は、木材を用いて木材板厚を0mm～100mmとした。また、直張り形式と浮かし張り形式の両方で検討を行い、浮かし張り形式では鋼部材３と耐火被覆材間距離trは、20mm、50mm、100mm、200mmとした。
図５に木材厚さtBと耐火時間の関係を示す。図５に示されるように、木材厚さtBが大きくなるにつれて耐火時間も長くなる。
The steel member 3 to be covered is a 300 x 16 square steel pipe, the fireproof covering material 5 is a calcium silicate plate with a thickness of 15 mm, and the wood material 7 is wood with a thickness of 0 mm to 100 mm. In addition, both the direct tension type and the floating type were investigated, and in the floating type, the distance t r between the steel member 3 and the fireproof coating was 20 mm, 50 mm, 100 mm, and 200 mm.
Figure 5 shows the relationship between wood thickness tB and fire resistance time. As shown in FIG. 5, as the wood thickness tB increases, the fire resistance time also increases.
図６に縦軸に木材ありのケースと木材無しのケースの耐火時間差を、横軸に木材の焼失までの時間（木材厚さtB/木材の焼失速度VB）をとったグラフを示す。図６に示されるように、直張り形式、浮かし張り形式の違いに関わらず、木材の焼失までの時間（tB/VB）が長くなれば、木材による耐火時間の増分が増加しており、増加の程度は木材の焼失までの時間と相関が見られる。
図６に示すグラフから、木材による耐火時間の増加量TBは以下の回帰式によって予測できる。
木材による耐火時間の増加量：TB=0.09×(tB/VB)1.4 ・・・(3)
FIG. 6 shows a graph in which the vertical axis shows the difference in fire resistance time between the case with wood and the case without wood, and the horizontal axis shows the time until the wood burns out (wood thickness t B / wood burning rate V B ). As shown in Figure 6, regardless of the difference between straight and floating types, as the time until wood burns out (t B /V B ) increases, the fire resistance time of the wood increases. , the degree of increase is correlated with the time until the wood burns out.
From the graph shown in FIG. 6, the amount of increase T B in fire resistance time due to wood can be predicted by the following regression equation.
Increase in fire resistance time due to wood: T B =0.09×(t B /V B ) 1.4 ...(3)
(2)式と(3)式から、耐火被覆材５を直張り形式で設置し、木質材７を耐火被覆材５の外側に設けた場合の鋼部材３の耐火時間Tcは、耐火被覆材５を単体で取り付けた場合の耐火時間TAと木質材７を耐火被覆材５に設けた場合の増加耐火時間TBの和、すなわちTc=TA＋TBとなる。
そして、このTcが鋼部材３に要求される耐火時間T以上であればよいので、T≦Tcすなわち、下記に示す式(1)を満たせばよい。
T≦TA＋TB ・・・(1)
From equations (2) and (3), the fire resistance time T c of the steel member 3 when the fire-resistant sheathing material 5 is installed in a straight-strung format and the wooden material 7 is provided outside the fire-resistant sheathing material 5 is calculated as follows: The sum of the fire resistance time T A when the wood material 5 is attached alone and the increased fire resistance time T B when the wood material 7 is provided on the fireproof covering material 5, that is, T c =T A +T B.
Since it is sufficient that this T c is equal to or longer than the fire resistance time T required for the steel member 3, it is sufficient that T≦T c , that is, the following formula (1) is satisfied.
T≦T A +T B・・・(1)
以上のように、本実施の形態によれば、被覆材を直張り形式とした場合において、被覆対象となる鋼部材３のサイズや、必要な耐火時間等の多様な仕様に対応し、かつ合理的に耐火被覆材５、木質材７の厚さが設定された耐火被覆構造となっている。
より具体的には、本実施の形態の図１、２に示す例では、被覆対象が鋼部材３を箱形断面の鋼管柱とし、建築物の梁のように天井に隠れることなく露出するもので耐火被覆材５の厚さを、従来の耐火被覆材単体による耐火被覆時の厚さよりも薄く設定している。
被覆対象の鋼部材３が梁の場合、多くの建物では天井に隠れているため、意匠性を考慮する必要がなく、被覆材の表面にさらに木質材７を設ける効果が小さい。
しかし、鋼管柱の場合は露出することが多いため、意匠性の観点から木質材７を用いるメリットがあり、この場合において、被覆材の厚みや密度を小さくすることで、合理的な耐火被覆構造となっており、また空間の自由度を増すことができる。
As described above, according to the present embodiment, when the sheathing material is directly stretched, it is possible to accommodate various specifications such as the size of the steel member 3 to be sheathed and the necessary fire resistance time, and to make it rational. The fireproof coating structure has a fireproof coating structure in which the thickness of the fireproof coating material 5 and the wood material 7 are set according to the specifications.
More specifically, in the example shown in FIGS. 1 and 2 of this embodiment, the steel member 3 to be coated is a steel pipe column with a box-shaped cross section, and is exposed without being hidden behind the ceiling like a beam of a building. The thickness of the fireproof covering material 5 is set to be thinner than the thickness of the conventional fireproof covering material alone.
When the steel member 3 to be covered is a beam, it is hidden behind the ceiling in many buildings, so there is no need to consider the design, and the effect of further providing the wood material 7 on the surface of the covering material is small.
However, in the case of steel pipe columns, they are often exposed, so there is an advantage of using wood material 7 from the viewpoint of design.In this case, by reducing the thickness and density of the covering material, a rational fire-resistant covering structure This also increases the degree of freedom in space.
なお、被覆材として吹付けロックウールを用いた場合において、図７に示すように、吹付けロックウールの必要厚さ以上の高さの不燃材からなるスペーサー１１を設け、木質材７とスペーサー１１を接合するようにしてもよい。
吹付けロックウールは、吹付け後に押圧した上で必要な厚さと密度を満足しなければならない。そのため押圧の仕方次第では密度や厚さにムラができ、場所によって耐火性能が異なってしまうことが懸念される。これに対して、図７に示すように、スペーサー１１を予め設けた上で、吹付けロックウールを十分な厚さだけ吹き付け、木質材７でスペーサー１１の高さ以下まで押圧することで一様な耐火被覆層が得られる。
また、木質材７が吹付けロックウールの水分を吸収して反ってしまうことが考えられるが、木質材７をスペーサー１１と接合することでこのような反りを抑えることが可能となる。
In addition, when sprayed rock wool is used as the covering material, as shown in FIG. may be joined together.
Sprayed rock wool must meet the required thickness and density after being pressed after spraying. Therefore, depending on the method of pressing, there may be unevenness in density and thickness, and there is a concern that the fire resistance performance will differ depending on the location. On the other hand, as shown in FIG. 7, spacers 11 are provided in advance, sprayed rock wool is sprayed to a sufficient thickness, and the wooden material 7 is pressed down to the height of the spacers 11 or below to uniformly A fire-resistant coating layer is obtained.
Furthermore, it is conceivable that the wooden material 7 absorbs water from the sprayed rock wool and becomes warped, but by joining the wooden material 7 with the spacer 11, such warping can be suppressed.
［実施の形態２］
上記の実施の形態は、鋼部材３の表面に接するように耐火被覆材５を配置した直張り形式の場合であったが、本実施の形態に係る耐火被覆構造１３は、図８に示すように、耐火被覆材５を鋼部材３から浮かした状態で配置する浮かし張り形式の場合である。
より具体的には、本実施の形態に係る耐火被覆構造１３は、鋼構造物を構成する鋼部材３の表面から離隔するように配置され、鋼部材３を覆う耐火被覆材５と、耐火被覆材５の外側に設けられた木質材７とを備えたものであって、下記の式(4)を満たすことを特徴とするものである。
T≦TA×α+TB (4)
TA=O×(tA×As/Hs)P+10
α＝Q+R×(Hr/Hs)S
TB=X×(tB/VB)Y
ただし、T：要求耐火時間(min)
TA：耐火被覆材を鋼部材に接するように設けた場合の耐火時間(min)
α：耐火被覆材の設置位置による係数
TB：木質材による耐火時間(min)
tA：耐火被覆材の厚さ(mm)
As：鋼部材の断面積(mm2)
Hs：鋼部材表面の周長(mm)
O，P：耐火被覆材の熱物性値、密度等から決まる定数
Hr：耐火被覆材内面の周長(mm)
Q,R,S：鋼部材断面による定数
tB：木質材の厚さ(mm)
VB：火災加熱時の木質材の炭化速度(mm/min)
X,Y：木質材の熱物性値，密度等から決まる定数
[Embodiment 2]
In the above embodiment, the fireproof covering structure 13 according to the present embodiment is a straight type in which the fireproof covering material 5 is arranged so as to be in contact with the surface of the steel member 3, but the fireproof covering structure 13 according to the present embodiment is In this case, the fireproof covering material 5 is placed in a floating state from the steel member 3.
More specifically, the fireproof covering structure 13 according to the present embodiment includes a fireproof covering material 5 that is arranged to be spaced apart from the surface of the steel member 3 constituting the steel structure, and a fireproof covering material 5 that covers the steel member 3; It is equipped with a wooden material 7 provided on the outside of the material 5, and is characterized in that it satisfies the following formula (4).
T≦T A ×α+T B (4)
T A =O×(t A ×A s /H s ) P +10
α＝Q+R×(H r /H s ) S
T B =X×(t B /V B ) Y
However, T: Required fire resistance time (min)
T A : Fire resistance time (min) when fireproof coating is installed in contact with steel members
α: Coefficient depending on the installation position of fireproof covering material
T B : Fire resistance time (min) of wood materials
t A : Thickness of fireproof coating material (mm)
A s : Cross-sectional area of steel member (mm 2 )
H s : Perimeter of steel member surface (mm)
O, P: Constants determined from the thermal properties, density, etc. of the fireproof coating material
H r : Circumference of inner surface of fireproof coating (mm)
Q,R,S: Constants depending on the steel member cross section
t B : Thickness of wood material (mm)
V B : Carbonization rate of wood material during fire heating (mm/min)
X,Y: Constants determined from the thermophysical properties of wood, density, etc.
本実施の形態に係る耐火被覆構造１は、図８に示すように、耐火被覆材５を浮かし張り形式で設置する場合を示しており、板状の耐火被覆材５と鋼部材３、具体的には角形鋼管柱との間に隙間を設けるために不燃材からなるスペーサー１５を設け、このスペーサー１５を介して耐火被覆材５と鋼部材３を接合している。そして、耐火被覆材５の角部は釘やビス等の固定具９で接合されている。 As shown in FIG. 8, the fireproof covering structure 1 according to the present embodiment shows a case where the fireproof covering material 5 is installed in a floating manner. A spacer 15 made of a noncombustible material is provided to provide a gap between the steel member and the square steel pipe column, and the fireproof covering material 5 and the steel member 3 are joined via this spacer 15. The corners of the fireproof coating 5 are joined with fixing tools 9 such as nails or screws.
実施の形態１の式(1)と本実施の形態の式(4)が異なる点は、本実施の形態では、TAに耐火被覆材５の設置位置による係数αを掛けている点である。
以下、αを掛けることの意義について説明する。
The difference between equation (1) of the first embodiment and equation (4) of this embodiment is that in this embodiment, T A is multiplied by a coefficient α depending on the installation position of the fireproof covering material 5. .
The significance of multiplying by α will be explained below.
前述のように、直張り形式と浮かし張り形式では耐火性能が異なり、その差は耐火被覆材５と鋼部材３の隙間の大きさや、鋼部材３のサイズによっても異なる。
そこで鋼部材３のサイズ、鋼部材３と耐火被覆材５の隙間の大きさをパラメータとした解析による検討を行った。
鋼部材３は□250x16、□300x16、□300x22、□500x16、□700x16の5断面の角形鋼管とし、鋼部材３と耐火被覆材５の隙間は10～300mmとした。耐火被覆材５は厚さ20mmのけい酸カルシウム板とした。物性値は実施の形態１と同様とした。解析結果を図９に示す。図９の縦軸は、耐火時間であり、横軸は耐火被覆材５と鋼部材３の距離trとした。
As mentioned above, the fire resistance performance differs between the direct tension type and the floating tension type, and the difference also varies depending on the size of the gap between the fireproof covering material 5 and the steel member 3 and the size of the steel member 3.
Therefore, an analysis was conducted using the size of the steel member 3 and the size of the gap between the steel member 3 and the fireproof coating 5 as parameters.
The steel member 3 was a square steel pipe with five cross sections of □250x16, □300x16, □300x22, □500x16, and □700x16, and the gap between the steel member 3 and the fireproof covering material 5 was 10 to 300 mm. The fireproof covering material 5 was a calcium silicate plate with a thickness of 20 mm. The physical property values were the same as in the first embodiment. The analysis results are shown in Figure 9. The vertical axis in FIG. 9 is the fire resistance time, and the horizontal axis is the distance tr between the fireproof coating 5 and the steel member 3.
図９を見ると分かるように、trが大きいほど耐火時間が低下しているが、その低下は、鋼部材３の大きさによって異なっている。
そこで、縦軸を耐火時間を直張り形式時の耐火時間で除した値とし、横軸を耐火被覆材５の内面の周長Hrを鋼部材３の周長Hsで除した値（Hr/Hs）としたグラフを図１０に示す。
図１０を見ると、断面サイズの違いによらず明瞭な相関が確認できる。そして、浮かし張り形式の場合の耐火時間と直張り形式の耐火時間比αは以下の回帰式によって予測できる。
α=0.15+1.1×(Hr/Hs)-0.83
As can be seen from FIG. 9, the fire resistance time decreases as t r increases, but the decrease differs depending on the size of the steel member 3.
Therefore, the vertical axis is the value obtained by dividing the fire resistance time by the fire resistance time in direct tension type, and the horizontal axis is the value obtained by dividing the inner circumference H r of the fireproof coating 5 by the circumference H s of the steel member 3 (H r /H s ) is shown in FIG. 10.
Looking at FIG. 10, a clear correlation can be confirmed regardless of the difference in cross-sectional size. The fire resistance time for the floating type and the fire resistance time ratio α for the direct type can be predicted by the following regression equation.
α=0.15+1.1×(H r /H s ) -0.83
したがって、浮かし張り形式の場合の耐火時間は、直張り形式時の耐火時間TAを用いて、TA×αと表すことができる。 Therefore, the fire resistance time in the floating type can be expressed as T A ×α using the fire resistance time T A in the direct type.
本実施の形態によれば、被覆材を浮かし張り形式とした場合において、実施の形態１と同様の効果、すなわち被覆対象となる鋼部材３のサイズや、必要な耐火時間等の多様な仕様に対応し、かつ合理的に耐火被覆材５、木質材７の厚さが設定された耐火被覆構造となっているという効果が得られる。 According to this embodiment, when the coating material is of a floating type, the same effect as in the first embodiment can be achieved, that is, it can be applied to various specifications such as the size of the steel member 3 to be coated and the required fire resistance time. The effect is that the fireproof coating structure has a correspondingly set thickness of the fireproof coating material 5 and the wood material 7 in a rational manner.
なお、上記の実施の形態１、２では、物の発明について説明したが、本発明は実施の形態１、２のそれぞれに対応する耐火被覆構造の設計方法としても構成することができる。この場合の設計方法としては、以下のようになる。 In the first and second embodiments described above, the invention of a product has been described, but the present invention can also be configured as a method for designing a fireproof covering structure corresponding to each of the first and second embodiments. The design method in this case is as follows.
＜直張り形式の場合の設計方法＞
鋼構造物を構成する鋼部材３の表面に接するよう配置されて鋼部材３を覆う耐火被覆材５と、耐火被覆材５の外側に設けられた木質材７とを備えた耐火被覆構造の設計方法であって、下式を満たすように設計することを特徴とする耐火被覆構造の設計方法。
T≦TA+TB
TA=O×(tA×As/Hs)P+10
TB=X×(tB/VB)Y
ただし、T：要求耐火時間(min)
TA：耐火被覆材を鋼部材に接するように設けた場合の耐火時間(min)
TB：木質材による耐火時間(min)
tA：耐火被覆材の厚さ(mm)
As：鋼部材の断面積(mm2)
Hs：鋼部材表面の周長(mm)
O，P：耐火被覆材の熱物性値、密度等から決まる定数
tB：木質材の厚さ(mm)
VB：火災加熱時の木質材の炭化速度(mm/min)
X,Y：木質材の熱物性値，密度等から決まる定数
<Design method for direct tension type>
Design of a fireproof covering structure comprising a fireproof covering material 5 placed in contact with the surface of a steel member 3 constituting a steel structure and covering the steel member 3, and a wood material 7 provided outside the fireproof covering material 5 A method for designing a fire-resistant covering structure, the method comprising designing a fire-resistant covering structure to satisfy the following formula.
T≦T A +T B
T A =O×(t A ×A s /H s ) P +10
T B =X×(t B /V B ) Y
However, T: Required fire resistance time (min)
T A : Fire resistance time (min) when fireproof coating is installed in contact with steel members
T B : Fire resistance time (min) of wood materials
t A : Thickness of fireproof coating material (mm)
A s : Cross-sectional area of steel member (mm 2 )
H s : Perimeter of steel member surface (mm)
O, P: Constants determined from the thermal properties, density, etc. of the fireproof coating material
t B : Thickness of wood material (mm)
V B : Carbonization rate of wood material during fire heating (mm/min)
X,Y: Constants determined from the thermophysical properties of wood, density, etc.
＜浮かし張り形式の場合の設計方法＞
鋼構造物を構成する鋼部材３の表面から離隔するように配置され、鋼部材３を覆う耐火被覆材５と、耐火被覆材５の外側に設けられた木質材７とを備えた耐火被覆構造の設計方法であって、下式を満たすように設計することを特徴とする耐火被覆構造の設計方法。
T≦TA+TB
TA=O×(tA×As/Hs)P+10
α＝Q+R×(Hr/Hs)S
TB=X×(tB/VB)Y
ただし、T：要求耐火時間(min)
TA：耐火被覆材を鋼部材に接するように設けた場合の耐火時間(min)
α：耐火被覆材の設置位置による係数
TB：木質材による耐火時間(min)
tA：耐火被覆材の厚さ(mm)
As：鋼部材の断面積(mm2)
Hs：鋼部材表面の周長(mm)
O，P：耐火被覆材の熱物性値、密度等から決まる定数
Hr：耐火被覆材内面の周長(mm)
Q,R,S：鋼部材断面による定数
tB：木質材の厚さ(mm)
VB：火災加熱時の木質材の炭化速度(mm/min)
X,Y：木質材の熱物性値，密度等から決まる定数
<Design method for floating type>
A fireproof covering structure that includes a fireproof covering material 5 that is arranged so as to be spaced apart from the surface of a steel member 3 constituting a steel structure and covers the steel member 3, and a wood material 7 that is provided on the outside of the fireproof covering material 5. A method for designing a fire-resistant covering structure, characterized in that the structure is designed to satisfy the following formula.
T≦T A +T B
T A =O×(t A ×A s /H s ) P +10
α＝Q+R×(H r /H s ) S
T B =X×(t B /V B ) Y
However, T: Required fire resistance time (min)
T A : Fire resistance time (min) when fireproof coating is installed in contact with steel members
α: Coefficient depending on the installation position of fireproof covering material
T B : Fire resistance time (min) of wood materials
t A : Thickness of fireproof coating material (mm)
A s : Cross-sectional area of steel member (mm 2 )
H s : Perimeter of steel member surface (mm)
O, P: Constants determined from the thermal properties, density, etc. of the fireproof coating material
H r : Circumference of inner surface of fireproof coating (mm)
Q,R,S: Constants depending on the steel member cross section
t B : Thickness of wood material (mm)
V B : Carbonization rate of wood material during fire heating (mm/min)
X,Y: Constants determined from the thermophysical properties of wood, density, etc.
１ 耐火被覆構造（実施の形態１）
３ 鋼部材
５ 耐火被覆材
７ 木質材
９ 固定具
１１ スペーサー
１３ 耐火被覆構造（実施の形態２）
１５ スペーサー
1 Fireproof coating structure (Embodiment 1)
3 Steel member 5 Fireproof coating material 7 Wooden material 9 Fixture 11 Spacer 13 Fireproof coating structure (Embodiment 2)
15 Spacer
Claims (3)
回帰式である下式を満たし、かつ前記耐火被覆材の厚さが、耐火被覆材単独で前記鋼部材を被覆する場合に必要とされる厚さよりも薄いことを特徴とする耐火被覆構造。
T≦TA×α+TB
TA=O×(tA×As/Hs)P+10
α＝Q+R×(Hr/Hs)S
TB=X×(tB/VB)Y
ただし、T：要求耐火時間(min)
TA：耐火被覆材単体を鋼部材に接するように設けた場合の耐火時間(min)
α：耐火被覆材の設置位置による係数
TB：木質材による耐火時間の増加量(min)
tA：耐火被覆材の厚さ(mm)
As：鋼部材の断面積(mm2)
Hs：鋼部材表面の周長(mm)
O，P：耐火被覆材の熱物性値、密度等から決まる定数
Hr：耐火被覆材内面の周長(mm)
Q,R,S：鋼部材断面による定数
tB：木質材の厚さ(mm)
VB：火災加熱時の木質材の炭化速度(mm/min)
X,Y：木質材の熱物性値，密度等から決まる定数 A plate-shaped fire-resistant covering material that is arranged via a spacer so as to be spaced apart from the surface of a steel member that is a column with a box-shaped cross section and covers the steel member, and a wooden material provided on the outside of the fire-resistant covering material. A fireproof covering structure comprising:
A fireproof coating structure that satisfies the following equation, which is a regression equation , and is characterized in that the thickness of the fireproof coating material is thinner than the thickness required when covering the steel member with the fireproof coating material alone.
T≦T A ×α+T B
T A =O×(t A ×A s /H s ) P +10
α＝Q+R×(H r /H s ) S
T B =X×(t B /V B ) Y
However, T: Required fire resistance time (min)
T A : Fire resistance time (min) when a single fireproof coating is installed in contact with a steel member
α: Coefficient depending on the installation position of fireproof covering material
T B : Increase in fire resistance time due to wood material (min)
t A : Thickness of fireproof coating material (mm)
A s : Cross-sectional area of steel member (mm 2 )
H s : Perimeter of steel member surface (mm)
O, P: Constants determined from the thermal properties, density, etc. of the fireproof coating material
H r : Circumference of inner surface of fireproof coating (mm)
Q,R,S: Constants depending on the steel member cross section
t B : Thickness of wood material (mm)
V B : Carbonization rate of wood material during fire heating (mm/min)
X,Y: Constants determined from the thermophysical properties of wood, density, etc.
TA=O×(tA×As/Hs)P+10で示される回帰式１を導出するステップと、
TB=X×(tB/VB)Yで示される回帰式２を導出するステップと、
当該鋼構造物の鋼部材に要求される要求耐火時間Tとの関係で、T≦TA+TBを満たすように耐火被覆材の耐火時間TA及び木質材による耐火時間TBを決定するステップと、
前記鋼部材との関係で、回帰式１を満たすように、耐火被覆材の厚さtAを決定するするステップと、回帰式２を満たすように、木質材の厚さtBを決定するするステップと、
を備えることを特徴とする耐火被覆構造の設計方法。
ただし、T：要求耐火時間(min)
TA：耐火被覆材単体を鋼部材に接するように設けた場合の耐火時間(min)
TB：木質材による耐火時間の増加量(min)
tA：耐火被覆材の厚さ(mm)
As：鋼部材の断面積(mm2)
Hs：鋼部材表面の周長(mm)
O，P：耐火被覆材の熱物性値、密度等から決まる定数
tB：木質材の厚さ(mm)
VB：火災加熱時の木質材の炭化速度(mm/min)
X,Y：木質材の熱物性値，密度等から決まる定数 A method for designing a fire-resistant covering structure comprising a fire-resistant covering material disposed in contact with the surface of a steel member constituting a steel structure and covering the steel member, and a wood material provided outside the fire-resistant covering material. hand,
a step of deriving regression equation 1 expressed as T A =O×(t A ×A s /H s ) P +10;
a step of deriving regression equation 2 represented by T B =X×(t B /V B ) Y ;
In relation to the required fire resistance time T required for the steel members of the steel structure, determine the fire resistance time T A of the fireproof coating material and the fire resistance time T B of the wood material so that T≦T A +T B is satisfied. step and
In relation to the steel member, the thickness tA of the fireproof covering material is determined so as to satisfy regression formula 1, and the thickness tB of the wood material is determined so as to satisfy regression formula 2. step and
A method for designing a fire-resistant covering structure, characterized by comprising:
However, T: Required fire resistance time (min)
T A : Fire resistance time (min) when a single fireproof coating is installed in contact with a steel member
T B : Increase in fire resistance time due to wood material (min)
t A : Thickness of fireproof coating material (mm)
A s : Cross-sectional area of steel member (mm 2 )
H s : Perimeter of steel member surface (mm)
O, P: Constants determined from the thermal properties, density, etc. of the fireproof coating material
t B : Thickness of wood material (mm)
V B : Carbonization rate of wood material during fire heating (mm/min)
X,Y: Constants determined from the thermophysical properties of wood, density, etc.
TA=O×(tA×As/Hs)P+10で示される回帰式１を導出するステップと、
TB=X×(tB/VB)Yで示される回帰式２を導出するステップと、
耐火被覆材の設置位置による係数αを導出するステップと、
当該鋼構造物の鋼部材に要求される要求耐火時間Tとの関係で、T≦TA×α+TBを満たすように耐火被覆材の耐火時間TA及び木質材による耐火時間TBを決定するステップと、
前記鋼部材との関係で、回帰式１を満たすように、耐火被覆材の厚さtAを決定するするステップと、回帰式２を満たすように、木質材の厚さtBを決定するするステップと、
を備えることを特徴とする耐火被覆構造の設計方法。
ただし、T：要求耐火時間(min)
TA：耐火被覆材単体を鋼部材に接するように設けた場合の耐火時間(min)
α：耐火被覆材の設置位置による係数
TB：木質材による耐火時間の増加量(min)
tA：耐火被覆材の厚さ(mm)
As：鋼部材の断面積(mm2)
Hs：鋼部材表面の周長(mm)
O，P：耐火被覆材の熱物性値、密度等から決まる定数
Hr：耐火被覆材内面の周長(mm)
Q,R,S：鋼部材断面による定数
tB：木質材の厚さ(mm)
VB：火災加熱時の木質材の炭化速度(mm/min)
X,Y：木質材の熱物性値，密度等から決まる定数 A method for designing a fire-resistant covering structure, which includes a fire-resistant covering material arranged to be spaced apart from the surface of a steel member constituting a steel structure and covering the steel member, and a wood material provided outside the fire-resistant covering material. And,
a step of deriving regression equation 1 expressed as T A =O×(t A ×A s /H s ) P +10;
a step of deriving regression equation 2 represented by T B =X×(t B /V B ) Y ;
a step of deriving a coefficient α depending on the installation position of the fireproof covering;
In relation to the required fire resistance time T required for the steel members of the steel structure, the fire resistance time T A of the fireproof coating material and the fire resistance time T B of the wood material are set so that T ≤ T A × α + T B. Steps to decide;
In relation to the steel member, the thickness tA of the fireproof covering material is determined so as to satisfy regression formula 1, and the thickness tB of the wood material is determined so as to satisfy regression formula 2. step and
A method for designing a fire-resistant covering structure, characterized by comprising:
However, T: Required fire resistance time (min)
T A : Fire resistance time (min) when a single fireproof coating is installed in contact with a steel member
α: Coefficient depending on the installation position of fireproof covering material
T B : Increase in fire resistance time due to wood material (min)
t A : Thickness of fireproof coating material (mm)
A s : Cross-sectional area of steel member (mm 2 )
H s : Perimeter of steel member surface (mm)
O, P: Constants determined from the thermal properties, density, etc. of the fireproof coating material
H r : Circumference of inner surface of fireproof coating (mm)
Q,R,S: Constants depending on the steel member cross section
t B : Thickness of wood material (mm)
V B : Carbonization rate of wood material during fire heating (mm/min)
X,Y: Constants determined from the thermophysical properties of wood, density, etc.
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