JP5839928B2 - Fireproof coated multilayer structure - Google Patents

Description

  The present invention relates to a fireproof coating to be applied to a pillar or beam that is a building frame.

  One of the verification methods in which a building is recognized as a fireproof building under the Building Standards Act is the fireproof performance verification method. In this verification method, the fire duration is calculated for each fire protection section, and the specifications of fireproof coating (used for the pillars and beams used as the building's building) are used so that the building can maintain its soundness as a structure during this fire duration. Material, coating thickness, etc.).

  Patent Document 1 discloses a fireproof coating in which a composite layer formed by laminating a heat-resistant bond layer, a heat-resistant ceramic fiber mat layer, a heat-resistant bond layer, and a stainless steel sheet layer on the surface of a construction structural material is used as one fire-resistant coating. A structure is disclosed.

  However, during renovation work (including design changes during construction) during use of the building, changes in the room usage that were originally set in the fire prevention area, opening size conditions when calculating the fire duration, etc. If the fire duration assumed for the fire protection zone becomes longer than the fire duration that was initially set due to changes in the conditions, the fireproof coating already applied is removed and a new setting is made. The building must have a fireproof coating with specifications that allow the building to remain sound as a structure during the fire duration.

JP-A-3-69758

  This invention considers the fact concerned, and makes it a subject to provide the fireproof coating multilayer structure which can respond to the specification change of a fireproof coating.

The invention of the first aspect is constituted by a steel frame member constituting a building beam or a column of a building, a fireproof coating structure constituted by a fireproof coating material surrounding the steel frame member, and a fireproof coating material surrounding the fireproof coating structure. A fireproof covering multilayer structure having a fireproof covering reinforcing structure.

In the first aspect of the invention, by surrounding the steel member with a plurality of fireproof coating materials, the fireproof performance can be improved as compared with the case of surrounding the steel member with one fireproof coating material. Moreover, when it becomes necessary to change the specifications of the fireproof coating, it is possible to respond flexibly (increase the fireproof performance).

The invention of a second aspect is the fireproof coating multilayer structure of the first aspect, wherein the fireproof coating reinforcing structure is constituted by a fireproof coating material surrounding the existing fireproof coating structure by post-construction.

In the second aspect of the invention, during the renovation work, the room use and the fire duration calculation conditions originally set in the fire prevention section are changed, and the fire duration assumed for the fire prevention section is changed. Ensure the fire resistance required in the modified fire protection area without raising the existing fireproof covering material (increase the fireproof performance) when it becomes longer than the fire duration set initially. Can do.

According to a third aspect of the present invention, in the fireproof coating multilayer structure of the first or second aspect, an end portion of the fireproof coating material surrounding the fireproof coating structure is fixed to the steel member.

In the invention of the third aspect , the fireproof coating material can be disposed so as to surround the fireproof coating structure when the fireproof coating material cannot be fixed to a floor slab or wall supported by the steel member.

According to a fourth aspect of the present invention, in the fireproof coating multilayer structure according to any one of the first to third aspects , a space is provided between the fireproof coating structure and the inner surface of the fireproof coating material surrounding the fireproof coating structure. Is formed.

In the invention of the fourth aspect, the steel member is surrounded by the space formed between the fireproof coating structure and the inner surface of the fireproof coating material surrounding the fireproof coating structure from the outside of the fireproof coating material surrounding the fireproof coating structure (fireproof coating). The heat transfer efficiency to the fireproof coating material (which constitutes the coating structure) can be reduced, and the heat shielding effect by the fireproof coating material surrounding the fireproof coating structure can be improved (the temperature rise of the steel member can be further reduced) . Moreover, a fireproof coating material can be easily attached compared with direct bonding.

  Since the present invention has the above-described configuration, it can cope with a change in specifications of the fireproof coating.

It is a front sectional view showing the fireproof covering multilayer structure concerning a 1st embodiment of the present invention. It is front sectional drawing which shows the fireproof coating multilayered structure which concerns on the 2nd Embodiment of this invention. It is front sectional drawing which shows the modification of the fireproof coating multilayered structure which concerns on the 2nd Embodiment of this invention. It is front sectional drawing which shows the modification of the fireproof coating multilayered structure which concerns on embodiment of this invention. It is front sectional drawing which shows the modification of the fireproof coating multilayered structure which concerns on embodiment of this invention. It is front sectional drawing which shows the modification of the fireproof coating multilayered structure which concerns on embodiment of this invention. It is front sectional drawing which shows the modification of the fireproof coating multilayered structure which concerns on embodiment of this invention. It is front sectional drawing which shows the modification of the fireproof coating multilayered structure which concerns on embodiment of this invention. It is front sectional drawing which shows the modification of the fireproof coating multilayered structure which concerns on embodiment of this invention. It is front sectional drawing which shows the modification of the fireproof coating multilayered structure which concerns on embodiment of this invention. It is front sectional drawing which shows the modification of the fireproof coating multilayered structure which concerns on embodiment of this invention. It is front sectional drawing which shows the modification of the fireproof coating multilayered structure which concerns on embodiment of this invention. It is front sectional drawing which shows the modification of the fireproof coating multilayered structure which concerns on embodiment of this invention. It is front sectional drawing which shows the modification of the fireproof coating multilayered structure which concerns on embodiment of this invention. It is front sectional drawing which shows the modification of the fireproof coating multilayered structure which concerns on embodiment of this invention. It is front sectional drawing which shows the modification of the fireproof coating multilayered structure which concerns on embodiment of this invention. It is front sectional drawing which shows the modification of the fireproof coating multilayered structure which concerns on embodiment of this invention.

  Embodiments of the present invention will be described with reference to the drawings. First, the fireproof coating multilayer structure according to the first embodiment of the present invention will be described.

  As shown in the front cross-sectional view of FIG. 1, the fireproof covering multilayer structure 10 includes a steel frame member 14 that constitutes a building beam of a building and supports the floor slab 12, a fireproof covering structure 16, and a fireproof covering reinforcing structure 18. ing. The floor slab 12 is formed of reinforced concrete or lightweight cellular concrete.

  The fireproof covering structure 16 is configured by directly sticking and surrounding the side and lower side of the steel frame member 14 with wet spray rock wool 20 as a fireproof covering material. The fireproof covering reinforcement structure 18 is configured by surrounding the sides and the lower side of the fireproof covering structure 16 with a box by a dry high heat-resistant rock wool sheet 23 as a fireproof covering material.

  The upper end portion of the high heat-resistant rock wool sheet 23 is fixed to the lower surface of the floor slab 12 with a concrete screw 26. Further, the lower end portion of the high heat-resistant rock wool sheet 23 is fixed to the lower flange 30 by welding the tip of the welding pin 28 penetrating the lower end portion to the lower surface of the lower flange 30.

  A space S is formed between the fireproof covering structure 16 (the outer surface of the spray rock wool 20) and the inner surface of the high heat resistant rock wool sheet 23.

  The fireproof coating structure 16 is an existing structure constructed during the new construction work, and the fireproof coating reinforcement structure 18 is a structure provided by post-construction work during the repair work.

  Next, the operation and effect of the fireproof multi-layer structure according to the first embodiment of the present invention will be described.

  In the fireproof coating multilayer structure 10 according to the first embodiment of the present invention, one fireproof coating is provided by surrounding the steel member 14 with a plurality of fireproof coating materials (sprayed rock wool 20 and high heat resistant rock wool sheet 23). The fire resistance can be improved as compared with the case where the steel member 14 is surrounded by the material. Moreover, when it becomes necessary to change the specifications of the fireproof coating, it is possible to respond flexibly (increase the fireproof performance).

  For example, during renovation work (including design changes in the middle of construction) during use of a building, etc., changes in the room usage originally set in the fire prevention area, opening size conditions when calculating the fire duration, etc. If the fire duration time assumed for the fire protection section becomes longer than the fire duration time initially set due to changes in the conditions, the spray rock wool 20 that is an existing fireproof covering material is removed. Without having to do so, it is possible to ensure the fire resistance required in the changed fire protection section (increase the fire resistance).

  In general, when changing usage from a merchandise store to a restaurant, depending on the specifications of the kitchen equipment, a new fire protection section (kitchen section) is required, and the fire duration required in this fire protection section (kitchen section) is required. It is often longer than the original design (product sales store). In addition, since the type of work accompanying this type of application change is often tenant work, and a short construction period and low cost are required, in such a situation, the fireproof covering compound according to the first embodiment of the present invention is required. Application of the layer structure 10 is particularly effective.

  Moreover, since it is not necessary to remove the spray rock wool 20 which is an existing fireproof coating material, it is expected to shorten the work period and reduce the cost which have been conventionally spent for the removal work of the existing fireproof coating material in the repair work or the like. . Further, by effectively utilizing the existing fireproof coating material, the material cost can be reduced and construction waste can be reduced.

  Further, the spray rock wool 20 from the outside of the high heat resistant rock wool sheet 23 is formed by the space S formed between the fireproof covering structure 16 (the outer surface of the spray rock wool 20) and the inner surface of the high heat resistant rock wool sheet 23. It is possible to reduce the heat transfer efficiency to and improve the heat shielding effect by the high heat-resistant rock wool sheet 23 surrounding the fireproof covering structure 16 (the temperature rise of the steel member 14 can be further reduced). Moreover, a fireproof coating material can be easily attached compared with direct bonding.

  The first embodiment has been described above.

  In the first embodiment of the present invention, the example in which the steel member 14 as the frame beam that supports the floor slab 12 is applied with fireproof coating has been described, but the present invention is also applied to the frame beam that does not support the floor slab 12. be able to. In this case, the fireproof coating structure 16 is configured by surrounding the entire outer periphery of the steel member 14 with the wet spray rock wool 20 as the fireproof coating material, and the dry high heat resistant rock wool sheet 23 as the fireproof coating material, The fireproof covering reinforcement structure 18 is configured by surrounding the entire outer periphery of the fireproof covering structure 16.

  Next, the fireproof multi-layer structure according to the second embodiment of the present invention, and its operation and effect will be described.

  In the description of the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals and are appropriately omitted. As shown in the front cross-sectional view of FIG. 2, the fireproof coated multilayer structure 32 of the second embodiment has the upper end portion of the high heat resistant rock wool sheet 23 fixed to the web 34 of the steel member 14 by the welding pin 28. Yes. Moreover, the blowing rock wool 20 that covers the upper flange 36 of the steel member 14 is not surrounded by the high heat-resistant rock wool sheet 23. In addition, a space S is formed between the fireproof covering structure 16 (the outer surface of the spray rock wool 20) and the inner surface of the high heat resistant rock wool sheet 23.

  Therefore, when it is difficult to fix the upper end portion of the high heat-resistant rock wool sheet 23 to the floor slab 12, the upper end portion of the high heat-resistant rock wool sheet 23 is fixed to the web 34 of the steel member 14, thereby providing a fireproof coating structure. The high heat-resistant rock wool sheet 23 can be disposed so as to surround 16 to form the fireproof covering reinforcing structure 38.

  Further, even when the blown rock wool 20 covering the upper flange 36 cannot be surrounded by the high heat-resistant rock wool sheet 23 due to the fact that a duct, wiring, or the like is disposed in the vicinity of the upper flange 36, fireproof coating reinforcement A structure 38 can be formed.

  The second embodiment of the present invention has been described above.

  In the second embodiment of the present invention, the spray rock wool 20 that covers the upper flange 36 of the steel member 14 is not surrounded by the high heat-resistant rock wool sheet 23, but the upper portion of the steel member 14 is shown. The blowing rock wool 20 covering the flange 36 may be surrounded by the high heat resistant rock wool sheet 23. Even if the spray rock wool 20 that covers the upper flange 36 of the steel frame member 14 is not surrounded by the high heat resistant rock wool sheet 23, the heat absorption effect of the spray rock wool 20 that constitutes the fireproof covering structure 16 is effective in the event of a fire. The fireproof covering structure 16 is configured by reducing the temperature rise of the steel member 14 to ensure fire resistance, and by the partial heat insulation (heat shielding) effect by the high heat resistant rock wool sheet 23 surrounding a part of the fireproof covering structure 16. Since the heat transmitted to the spray rock wool 20 is reduced and the temperature rise of the steel member 14 is further reduced, the fire resistance can be improved as compared with the case where the steel member 14 is surrounded by one fireproof covering material.

  Further, in the second embodiment of the present invention, the example in which the upper end portion of the high heat-resistant rock wool sheet 23 is fixed to the web 34 of the steel member 14 is shown, but the fireproof covering multilayer structure shown in the front sectional view of FIG. As shown at 40, the upper end portion of the high heat-resistant rock wool sheet 23 may be fixed to the upper flange 36 of the steel member 14 by the welding pin 28 to form the fireproof covering reinforcement structure 42.

  The first and second embodiments of the present invention have been described above.

  In the first and second embodiments of the present invention, the fireproof coating material surrounding the steel member 14 (which constitutes the fireproof coating structure 16) is the spray rock wool 20, and the fireproof coating material surrounding the fireproof coating structure 16 is used. Although the example made into the high heat-resistant rock wool sheet | seat 23 was shown, the fire-resistant coating | covering material which surrounds the steel frame member 14 (it comprises the fire-resistant coating structure 16) should just be a member which can provide fire resistance to the steel frame member 14, and fireproof coating | covering The fireproof covering material surrounding the structure 16 may be any member that can impart fire resistance to the fireproof covering structure 16 and improve the fire resistance of the steel member 14.

  Examples of the fireproof coating material surrounding the steel member 14 (which constitutes the fireproof coating structure 16) and the fireproof coating material surrounding the fireproof coating structure 16 include wet spray rock wool, fireproof paint, dry rock wool sheets, A heat-resistant rock wool sheet, a thermal expansion sheet, a calcium silicate board, and a gypsum board are mentioned.

  The dry fireproof covering material may be attached directly to the steel member 14, the fireproof covering structure 16 or the like, or may be attached by box attachment. Further, when the wet type fireproof coating material surrounding the fireproof coating structure 16 is used as the fireproof coating material, the fireproof coating material may be applied to the surface of the fireproof coating material surrounding the steel member 14 (which constitutes the fireproof coating structure 16). . Further, a plurality of fireproof coating materials surrounding the steel member 14 (which constitute the fireproof coating structure 16) and fireproof coating materials surrounding the fireproof coating structure 16 may be provided in a stacked manner.

  Further, the fireproof coating material surrounding the steel member 14 (which constitutes the fireproof coating structure 16) and the fireproof coating material surrounding the fireproof coating structure 16 may be the same material or different materials. For example, it is good also as fireproof covering multilayer structure 44, 46, 48, 50 shown to front sectional drawing of FIGS.

  In the fireproof coating multilayer structure 44 of FIG. 4, the fireproof coating reinforcing structure 52 is formed by directly pasting the sides and the lower side of the fireproof coating structure 16 with a dry high heat resistant rock wool sheet 23 as a fireproof coating material. It is composed. In the case where the beam penetration part is formed in the steel member 14, the fire resistance around the beam penetration part can be ensured, and thus the fireproof covering multilayer structure 44 is suitable.

  In the fireproof coating multilayer structure 46 of FIG. 5, a fireproof coating structure 54 is formed by applying a wet fireproof paint 58 as a fireproof coating material to the surface of the steel member 14, and a dry high heat resistance as a fireproof coating material. The rock wool sheet 23 forms a fireproof covering reinforcing structure 56 by surrounding the fireproof covering structure 54 on the sides and the lower side thereof with a box. A space S is formed between the fireproof covering structure 54 (the outer surface of the fireproof paint 58) and the inner surface of the high heat resistant rock wool sheet 23.

  In the fireproof covering multilayer structure 48 of FIG. 6, the fireproof covering structure 60 is configured by surrounding the side and bottom of the steel member 14 with a box by a dry high heat resistant rock wool sheet 23 as a fireproof covering material. The fireproof covering reinforcing structure 62 is configured by directly adhering the sides and the lower side of the fireproof covering structure 60 with the dry high heat resistant rock wool sheet 23 as the fireproof covering material. A space V is formed between the steel member 14 and the inner surface of the high heat-resistant rock wool sheet 23 constituting the fireproof covering structure 60.

  In the fireproof covering multilayer structure 50 of FIG. 7, the fireproof covering structure 64 is constituted by directly sticking the side and the lower side of the steel member 14 with the dry high heat resistant rock wool sheet 23 as the fireproof covering material. The fireproof covering reinforcing structure 66 is configured by directly adhering the sides and the lower side of the fireproof covering structure 64 with the dry high heat resistant rock wool sheet 23 as the fireproof covering material.

  Further, in the first and second embodiments of the present invention, an example in which the side and the lower side of the fireproof coating structure 16 are surrounded by the dry high heat resistant rock wool sheet 23 as the fireproof coating material is shown. A part of the fire-resistant coating structure 16 may be covered with a fire-resistant coating material, as in the fire-resistant coating multilayer structures 68, 100, 106, and 110 shown in the front sectional views of FIGS.

  As shown in FIGS. 8 and 9, in the fireproof coating multilayer structures 68 and 100, the fireproof coating reinforcing structure 70, by covering only the sides of the fireproof coating structure 16 with a dry calcium silicate plate 72 as a fireproof coating material, 102 is configured. In the fireproof coating multilayer structure 68, a space S is formed between the fireproof coating structure 16 (the outer surface of the spray rock wool 20) and the inner surface of the calcium silicate plate 72. In the fireproof coating multilayer structure 100, the fireproof coating structure 16 (the outer surface of the spray rock wool 20) and the inner surface of the calcium silicate plate 72 are in contact.

  In the fireproof coating multilayer structure 106 of FIG. 10, only the sprayed rock wool 20 covering the lower flange 30 of the steel member 14 is directly pasted and surrounded by the dry high heat resistant rock wool sheet 23 as the fireproof coating material. A fireproof covering reinforcing structure 108 is formed. The upper end portion of the high heat resistant rock wool sheet 23 is fixed to the upper surface of the lower flange 30 of the steel member 14 by a welding pin 28, and the lower end portion of the high heat resistant rock wool sheet 23 is fixed to the lower flange of the steel member 14 by the welding pin 28. 30 is fixed to the lower surface.

  11, the dry high heat-resistant rock wool sheet 23 as a fireproof coating material is used to form a part of the lower flange 30 of the steel member 14 and part of the web 34 (for example, the lower 1/3 of the web 34). The fireproof covering reinforcement structure 112 is configured so as to surround only the sprayed rock wool 20 covering about 1/2) with a box. Further, the upper end portion of the high heat resistant rock wool sheet 23 is fixed to the web 34 of the steel member 14 by the welding pin 28, and the lower end portion of the high heat resistant rock wool sheet 23 is fixed to the lower surface of the lower flange 30 of the steel member 14 by the welding pin 28. It is fixed to.

  In the fireproof covering multilayer structure 68, 100, 106, 110, the heat absorption effect of the spray rock wool 20 reduces the temperature rise of the steel frame member 14 at the time of a fire to ensure fire resistance, and the calcium silicate plate 72 and the high heat resistance Since the heat transmitted to the spray rock wool 20 is reduced by the partial heat insulation (heat shielding) effect by the rock wool sheet 23, the temperature rise of the steel member 14 is further reduced. The fire resistance can be improved as compared with the case of surrounding 14. Moreover, since only a part of the fireproof coating structure 16 may be covered with the fireproof coating material (calcium silicate plate 72, high heat resistant rock wool sheet 23), the construction can be easily performed. Moreover, in the fireproof covering multilayered structures 106 and 110, when the beam penetration part is formed in the steel member 14, it can prevent that construction of a fireproof coating reinforcement structure becomes complicated by presence of this beam penetration part. .

  Further, in the first and second embodiments of the present invention, an example in which the side and the lower side of the fireproof coating structure 16 are surrounded by the dry high heat resistant rock wool sheet 23 as the fireproof coating material is shown. As shown in the fire-resistant covering multilayer structure 74 shown in the front sectional view of FIG. 12, the sides and the lower side of the fire-resistant covering structure 16 from which a part of the spray rock wool 20 is removed may be surrounded. In FIG. 12, the side and the lower side of the fireproof covering structure 16 from which a part of the sprayed rock wool 20 (two-dot chain line part) is removed are covered with a dry high heat resistant rockwool sheet 23 as a fireproof covering material. The fireproof covering reinforcing structure 76 is configured by the above.

  In the fireproof covering multi-layer structure 74, in the repair work, the construction labor is reduced compared to removing all of the high heat resistant rock wool sheet 23 and newly covering.

  In the first and second embodiments of the present invention, the steel member 14 constituting the building beam of the building has been shown as an application target of the fireproof coated multilayer structures 10, 32, 40. Steel frame members constituting the columns may be applied to the fireproof multi-layer structures 10, 32, and 40.

  When a fireproof coating is applied to a frame column supporting a wall, for example, the fireproof coating multilayer structure 10, 32, 40, 44, 46, 48, 50, 68, 74, 100 shown in FIGS. , 106, 110 may be regarded as a plan sectional view, and the steel member 14 may be a frame column and the floor slab 12 may be a wall.

  Further, when the fireproof coating is applied to the frame pillar that does not support the wall, for example, the fireproof coating multilayer structures 80, 82, 84, 86, and 104 shown in the plan sectional views of FIGS. Good. That is, you may make it comprise the fireproof covering multilayer structure 80, 82, 84, 86, 104 by enclosing all the outer periphery of the steel frame member 78 as a frame pillar with a fireproof covering material doubly.

  Further, in the first embodiment of the present invention, the fireproof coating structure 16 is an existing structure constructed during the new construction, and the fireproof coating reinforcement structure 18 is a structure provided by post-construction during the repair work, Although the example which applied the fireproof covering multilayered structure 10 to repair work was shown, the fireproof covering multilayered structures 10, 32, and 40 shown in the first and second embodiments may be applied to repair work. It may be applied to new construction. For example, when building a new building with various fire durations for each fire protection section, the same specifications (material type and thickness) of the fireproof covering are applied to the frame pillars and beams in each fire protection section. After covering with a material, if a fireproof covering reinforcing structure having specifications according to the fire duration time of each section is constructed, construction can be performed efficiently.

  Further, in the first embodiment, it has been described that the heat shielding effect of the fireproof coating material surrounding the fireproof coating structure is improved by the space S of the fireproof coating multilayer structure 10, but the fireproof coating multilayer structure 32, The same effect can be obtained by the space S of 40, 46, 68, 74, 80, 84, 86, 110.

  In addition, as a fireproof design method for constructing the fireproof coated multilayer structures 10, 32, and 40 shown in the first and second embodiments of the present invention, first, a steel member constituting a building beam or a building column of a building is used. A fireproof coating material is arranged so as to surround the fireproof coating structure, and then a fireproof coating material is arranged so as to surround the fireproof coating structure to constitute a fireproof coating reinforcing structure.

  In addition, the fireproofing used in the fireproof coated multilayer structures 10, 32, 40, 44, 46, 48, 50, 68, 74, 80, 82, 84, 86, 100, 104, 106, 110 described so far. It is preferable that the covering material has received “Ministerial certification as a material” for the use of a plurality of layers, but even when such “Ministerial certification as a material” is not received, a plurality of fireproof coating materials are used. If you have obtained “Ministerial certification as a building” including the use of multiple items as certification conditions, you can use multiple items under the Construction Standard Act.

  As mentioned above, although 1st and 2nd embodiment of this invention was described, this invention is not limited to such embodiment at all, You may use combining 1st and 2nd embodiment, Needless to say, the present invention can be implemented in various modes without departing from the gist of the present invention.

10, 32, 40, 44, 46, 48, 50, 68, 74, 80, 82, 84, 86, 100, 104, 106, 110 Fireproof multi-layer structure 14, 78 Steel members 16, 54, 60, 64 Fireproof covering structure 18, 38, 42, 52, 56, 62, 66, 70, 76, 102, 108, 112 Fireproof covering reinforcing structure 20 Spray rock wool (fireproof covering material)
23 High heat-resistant rock wool sheet (fireproof coating)
58 Fireproof paint (fireproof coating)
72 Calcium silicate board (fireproof coating)
S space

Claims (5)

A steel member constituting the building beam or column of the building;
A fireproof covering structure constituted by a first fireproof covering material surrounding the steel member;
A fireproof covering reinforcing structure constituted by a second fireproof covering material surrounding only the fireproof covering structure surrounding the lower flange of the steel member and the web, or surrounding only the fireproof covering structure surrounding the web of the steel member ;
A fireproof coated multilayer structure. A steel member constituting the building beam or column of the building;
A fireproof covering structure constituted by a first fireproof covering material surrounding the steel member;
A fireproof covering reinforcing structure constituted by a second fireproof covering material surrounding only the fireproof covering structure surrounding the lower flange of the steel member;
A fireproof coated multilayer structure. The fireproof coating multilayer structure according to claim 1, wherein a space is formed between the fireproof coating structure and an inner surface of the second fireproof coating material surrounding the fireproof coating structure. The fireproof covering multilayer structure according to any one of claims 1 to 3, wherein the second fireproof covering material surrounding the fireproof covering structure is fixed to the steel member. The construction method of the fireproof coating multilayer structure of any one of Claims 1-4 WHEREIN: The construction method of the fireproof coating multilayer structure which surrounds the said existing fireproof coating structure by said 2nd fireproof coating material by post-construction.

Images