Fireproof board frame, ceiling embedded device installation structure, and ceiling embedded device installation method

Abstract

To provide a fireproof board frame, an installation structure of a ceiling-embedded device and an installation method of the ceiling-embedded device capable of forming a fire protection line without requiring a double ceiling structure and capable of being easily constructed.SOLUTION: A fireproof board frame 1 comprises: four vertical frame portions 11 fixed to a ceiling joist 6 formed around a rectangular opening 5 opened in a ceiling to extend upward and formed at each corner portion of the rectangular opening 5; and four upper frame portions 12 formed in a rectangular shape so as to connect upper ends of the vertical frame portions 11. The vertical frame portions 11 serve as substrates of side edges of side face fireproof boards 9 forming side faces of a box-like space 7 formed in a ceiling. The upper frame portions 12 serve as substrates of upper edges of the side face fireproof boards 9 and of an outer periphery of an upper face fireproof board 8 forming an upper face of the box-like space 7.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a fireproof board frame that serves as a base for fixing a fireproof board that forms a box-shaped space by recessing part of the ceiling surface upward in order to install a ceiling-embedded device such as a built-in air conditioner or a ventilation fan above the ceiling, an installation structure for the ceiling-embedded device using the fireproof board frame, and an installation method for the ceiling-embedded device. [Background technology]

[0002] Among conventional air conditioners and ventilation fans, various types of ceiling-embedded type that are embedded in the ceiling have been known. One known method for supporting such ceiling-embedded devices in a building is to support the ceiling-embedded device so that a hanging bracket protruding from the ceiling-embedded device is fixed to a hanging bolt supported on the building frame above the ceiling, thereby supporting the ceiling-embedded device in a suspended manner (see Patent Document 1 and Patent Document 2).

[0003] The above-mentioned ceiling-mounted device installation structure has hanging hardware and hanging bolts attached to the ceiling-mounted device, and these hanging hardware and hanging bolts get in the way, so when covering it with a mat of insulating material, it is difficult to wrap it around the ceiling-mounted device and it is also difficult to wrap it without gaps. Also, when covering it with a board of insulating material, it is difficult to avoid interference with the hanging hardware and hanging bolts, and on-site processing work such as cutting notches is required, which makes construction time-consuming.

[0004] Therefore, in order to facilitate the application of the insulating coating and to ensure a certain level of insulating performance, the applicant of the present application proposed an installation structure for a ceiling-embedded device in which an insulating box with an opening downward is suspended from the main body and the ceiling-embedded device is fixed inside the insulating box (see Patent Document 3). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-320888 [Patent Document 2] Japanese Patent Application Laid-Open No. 2001-235177 [Patent Document 3] Japanese Patent Application Laid-Open No. 2017-146012 Summary of the Invention [Problem to be solved by the invention]

[0006] Incidentally, the insulation box in Patent Document 3 is made of glass wool board or rock wool board, and is unable to ensure the fire resistance equivalent to the 15mm reinforced gypsum board required for a one-hour quasi-fire-resistant structure. Therefore, in order to design a one-hour quasi-fire-resistant structure while arranging ceiling-embedded devices, it is necessary to create a double ceiling structure by forming a fire line made of 15mm reinforced gypsum board above the ceiling and ceiling-embedded devices, and suspending the gypsum board that forms the ceiling and the ceiling-embedded devices below the fire line.

[0007] However, a double-ceiling structure reduces the ceiling's lowering, reducing design freedom and potentially reducing livability. It also requires two separate tasks: installing reinforced gypsum board for the fire line and installing the gypsum board for the ceiling, which increases the construction time and effort. Furthermore, the components for suspending the ceiling-mounted device penetrate the reinforced gypsum board that forms the fire line, making the construction more difficult and requiring additional work, such as applying fire-resistant putty to the penetrations to maintain the fire line.

[0008] Therefore, the present invention aims to provide a fireproof board frame, a ceiling-embedded device installation structure, and a ceiling-embedded device installation method that can form a fire prevention line without requiring a double ceiling structure and that also makes installation easy. [Means for solving the problem]

[0009] The fire-resistant board frame of the present invention extends upward and is fixed to ceiling joists formed around a rectangular opening in the ceiling, and is equipped with four vertical frame sections formed at each corner of the rectangular opening, and four upper frame sections formed in a rectangular shape so as to connect the upper ends of the vertical frame sections.The vertical frame sections form the base for the side edge sections of the side fire-resistant boards that form the sides of the box-shaped space formed above the ceiling, and the upper frame sections form the base for the upper edge sections of the side fire-resistant boards and the outer periphery of the upper fire-resistant board that forms the top surface of the box-shaped space.

[0010] The fire-resistant board frame of the present invention is characterized in that the vertical frame portion and the upper frame portion are detachable from each other.

[0011] The fire-resistant board frame of the present invention is characterized in that an intermediate frame portion, which serves as a base for the upper fire-resistant board, is installed midway in the lengthwise direction between the two opposing upper frame portions.

[0012] The fire-resistant board frame of the present invention is characterized in that the vertical frame portion is formed with a fall prevention portion that abuts against the upper surface of the ceiling joist.

[0013] The fire-resistant board frame of the present invention is characterized in that it has a locking portion at its upper end that locks into a fixing hole formed in the upper frame portion, and further comprises a fall prevention hook that hangs down inside the side fire-resistant board and has a temporary fixing portion at its lower end for suspending an equipment fixing frame that fixes a ceiling-embedded device installed in the box-shaped space.

[0014] The installation structure of the ceiling embedded device of the present invention comprises: The above a fire-resistant board frame; an upper fire-resistant board to which the upper frame portion of the fire-resistant board frame is attached as a base; and a side fire-resistant board to which the vertical frame portion of the fire-resistant board frame is attached as a base; 5. The upper surface of the fireproof board and Side fireproof board The ceiling mounting device is characterized by comprising: an equipment fixing frame that is arranged inside the box-shaped space formed by the above and fixed to the ceiling joist; and a ceiling embedding device that is arranged in the box-shaped space and fixed to the equipment fixing frame.

[0015] The installation method for a ceiling-embedded device of the present invention is a method for installing a ceiling-embedded device that constructs the installation structure for the above-mentioned ceiling-embedded device, and is characterized by comprising the steps of: fixing the vertical frame portion of the fire-resistant board frame to the ceiling joist; fixing the top fire-resistant board to the upper frame portion of the fire-resistant board frame and fixing the side fire-resistant board to the vertical frame portion; placing the equipment fixing frame inside the box-shaped space formed inside by the top fire-resistant board and the side fire-resistant board and fixing it to the ceiling joist; and placing the ceiling-embedded device in the box-shaped space and fixing it to the equipment fixing frame. [Effects of the Invention]

[0016] According to the fireproof board frame of the present invention, the four vertical frame portions form the base for the side edges of the four side fireproof boards that form the box-shaped space, and the upper frame portion forms the base for the upper edges of the side fireproof boards and the outer periphery of the top fireproof board. By using the ceiling joists as the base for the lower edges of the side fireproof boards, the peripheries of the side fireproof boards and the top fireproof board can be fixed with appropriate screw pitches, forming a box-shaped space with appropriate fire resistance, thereby creating an appropriate fire protection line without requiring a double ceiling structure. Furthermore, since the base for the fireproof boards is formed simply by fixing such fireproof board frames to the ceiling joists, construction is simplified. Since there is no need to lower the ceiling because it is not a double ceiling, design freedom is increased, and the construction effort required to create a double ceiling is reduced.

[0017] According to the fire-resistant board frame of the present invention, the vertical frame portion and the upper frame portion are configured to be detachable from each other, which makes it easy to transport the fire-resistant board frame to a construction site.

[0018] According to the fire-resistant board frame of the present invention, an intermediate frame portion that serves as the base for the upper fire-resistant board is erected midway between the two opposing upper frame portions in the longitudinal direction, so that the upper fire-resistant board can be fixed with an appropriate screw pitch not only around its periphery but also in the middle, thereby ensuring sufficient fire resistance of the ceiling.

[0019] According to the fire-resistant board frame of the present invention, a fall prevention portion that abuts the upper surface of the ceiling joist is formed in the vertical frame portion.Therefore, when fixing the fire-resistant board frame to the ceiling joist, the fall prevention portion can be hooked onto the ceiling joist to prevent the fire-resistant board frame from falling, thereby improving workability and safety.

[0020] According to the fireproof board frame of the present invention, the fall prevention hooks hang down from the inside of the side fireproof board to suspend the equipment fixing frame, so that the height of the equipment fixing frame can be adjusted and it can be easily installed in an appropriate position, making the installation work of the equipment fixing frame safe and easy.

[0021] According to the installation structure for a ceiling-embedded device of the present invention, a box-shaped space is formed by attaching a top fireproof board and side fireproof boards to a fireproof board frame, and the equipment fixing frame and ceiling-embedded device are installed inside the box-shaped space. Therefore, the top fireproof board and side fireproof boards can serve as a fire prevention line, and the opening in the ceiling formed for installing the ceiling-embedded device can be properly fireproofed. Furthermore, because the equipment fixing frame that fixes the ceiling-embedded device is fixed to the ceiling joist, there is no need for a member to suspend the ceiling-embedded device, and there is no need to penetrate the fireproof board to connect the suspending member to the ceiling-embedded device. This makes installation easier and eliminates the installation work of applying fireproof putty to the penetration part.

[0022] According to the method for installing a ceiling-embedded device of the present invention, a fireproof board frame is fixed to a ceiling joist, and then a top fireproof board and a side fireproof board are installed on the fireproof board frame to form a box-shaped space that constitutes a fire prevention line.The equipment fixing frame and ceiling-embedded device are placed and fixed inside this box-shaped space, so the ceiling-embedded device can be easily installed while ensuring a fire prevention line.Since a double ceiling is not required to form a fire prevention line, workability is improved and ceiling height can be increased or the degree of freedom in designing the ceiling recess can be increased. [Brief explanation of the drawings]

[0023] [Figure 1]FIG. [Figure 2] FIG. 2 is a perspective view showing the overall configuration of a fire-resistant board frame. [Figure 3] A diagram illustrating how the fireproof board frame is fixed to the ceiling joist. [Figure 4] 10 is a perspective view illustrating a top fireproof board and a side fireproof board to which the fireproof board frame is attached as a base. FIG. [Figure 5] 10 is a cross-sectional view illustrating the state in which the upper fireproof board is fixed to the upper frame portion with screws. FIG. [Figure 6] FIG. 2 is a perspective view illustrating the overall configuration of the fall prevention hook. [Figure 7] A cross-sectional view illustrating the state in which the side fireproof board is fixed to the side frame portion with screws and the fall prevention hook is hooked into the fixing hole and the top surface of the side fireproof board. [Figure 8] 10 is a diagram illustrating a state in which an equipment fixing frame is fixed to a fall prevention hook within a box-shaped space formed by an upper fireproof board and a side fireproof board. FIG. [Figure 9] FIG. 2 is a perspective view illustrating the overall configuration of the device fixing frame. [Figure 10] 10A and 10B are diagrams illustrating a state in which the device fixing frame is temporarily fixed to the fall prevention hook. [Figure 11] FIG. 10 is a diagram illustrating the state in which the equipment fixing frame is fixed to the ceiling joist. [Figure 12] FIG. 10 is a diagram illustrating the state in which the equipment fixing frame is fixed to the ceiling joist. [Figure 13] FIG. 4 is a cross-sectional view illustrating a state in which the ceiling-embedded device is fixed to the equipment fixing frame. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, embodiments of a fireproof board frame 1, a ceiling-mounted device installation structure 2, and a ceiling-mounted device installation method according to the present invention will be described with reference to the accompanying drawings. The ceiling-mounted device 3 is installed above a ceiling where a built-in air conditioner or a ventilation fan is installed, with its underside exposed on the ceiling surface, for indoor air conditioning and ventilation. The ceiling surface is formed by fixing 15-mm-thick reinforced gypsum board ceiling panels 4 to a ceiling joist 6. The ceiling panels 4 have the non-combustibility required for a one-hour quasi-fire-resistant structure. A rectangular opening 5 is formed in the ceiling surface to expose the underside of the ceiling-mounted device 3. Therefore, for example, in a one-hour quasi-fire-resistant structure, if the ceiling panels 4 are used as a firestop, the rectangular opening 5 for exposing the underside of the ceiling-mounted device 3 will be a gap in the firestop, making it necessary to provide a continuous firestop within the ceiling cavity.

[0025] As shown in Figure 13, the installation structure 2 for a ceiling embedded device in which such a ceiling embedded device 3 is installed comprises a fire-resistant board frame 1 fixed to a ceiling joist 6, a top fire-resistant board 8 and a side fire-resistant board 9 attached to the inside of the fire-resistant board frame 1 to form a box-shaped space 7, an equipment fixing frame 10 arranged inside the box-shaped space 7 and fixed to the ceiling joist 6, and a ceiling embedded device 3 arranged inside the box-shaped space 7 and fixed to the equipment fixing frame 10.

[0026] The ceiling joist 6 is a hollow steel square tube that forms the base for the ceiling boards 4 that make up the ceiling surface. The ceiling boards 4 are attached and fixed to the underside of the ceiling joist 6 with screws spaced at regular intervals, and a decorative material such as wallpaper (not shown) is attached underneath to form the ceiling surface. The ceiling joist 6 is arranged around the periphery of a rectangular opening 5 formed in the ceiling surface.

[0027] 1 and 2, the fire-resistant board frame 1 is arranged at the corners of the rectangular opening 5 and has four vertical frame sections 11 that rise from the corners toward the ceiling, four upper frame sections 12 that are arranged to connect the upper ends of the vertical frame sections 11, and an intermediate frame section 13 that is installed between two opposing upper frame sections 12. The fire-resistant board frame 1 is formed in the shape of a rectangular parallelepiped frame, with the four upper frame sections 12 forming a horizontal rectangular frame and vertical frame sections 11 being formed so as to hang down from each corner of the rectangular frame.

[0028] The vertical frame portion 11 is formed by bending a long thin steel plate at a right angle, elongating the vertical direction and forming a mountain-shaped, isosceles right-angled cross section. Each of the two plate surfaces constituting the vertical frame portion 11 has a protruding fall prevention portion 14 that abuts against the upper surface of the ceiling joist 6 formed around the periphery of the rectangular opening 5 in the ceiling surface. The fall prevention portion 14 is formed on each of the two plate surfaces of the vertical frame portion 11. A rectangular slit with its upper edge connected is provided in the vertical frame portion 11, and the plate surface inside the slit is raised and raised obliquely downward to form a fin-like shape. The vertical distance between the lower end of the fall prevention portion 14 and the lower end of the vertical frame portion 11 is approximately equal to the height of the ceiling joist 6. As shown in FIG. 3 , when the lower end of the fall prevention portion 14 abuts against the upper surface of the ceiling joist 6, the lower end of the vertical frame portion 11 is approximately equal to the height of the lower surface of the ceiling joist 6.

[0029] The upper frame portion 12 is formed long in the horizontal direction and has side portions 15 with vertical surfaces, and an upper portion 16 formed by bending the upper ends of the side portions 15 at a right angle toward the inside of the fireproof board frame 1. Two rectangular fixing holes 17 are formed in each side portion 15 of the upper frame portion 12, spaced apart horizontally. The fixing holes 17 are formed in a rectangular shape that is long in the horizontal direction and short in the vertical direction, and fall prevention hooks 18, which will be described later, can be hung on the fixing holes 17.

[0030] The middle frame portion 13 is formed by bending both ends downward of a long, horizontally formed thin steel plate, and both ends are fixed by abutting against the two upper frame portions 12. Both side edges of the middle frame portion 13 in the width direction rise upward, ensuring rigidity as a base for fixing the upper fire-resistant board 8.

[0031] The fireproof board frame 1 is made up of four vertical frame sections 11, four upper frame sections 12, and an intermediate frame section 13, each of which is fixed and connected with bolts and nuts, and can be detached from one another by tightening or loosening the bolts. As each section is detachable in this way, space can be saved when transporting to a construction site or during storage. Note that the fireproof board frame 1 of the present invention is not limited to a configuration in which each section is detachable, and may be assembled into a box shape by welding or the like and transported to a construction site.

[0032] As shown in Figures 4 and 5, the top fire-resistant boards 8 are approximately square reinforced gypsum boards. They abut from below against the upper portions 16 of the four upper frame portions 12, which form the horizontal surface of the upper frame portions 12, and their peripheries are fastened with screws to form the upper surface of the box-shaped space 7 inside the fire-resistant board frame 1. The top fire-resistant boards 8 are also fastened with screws at their centers along the middle frame portion 13, thereby providing fire resistance. The side fire-resistant boards 9 are four rectangular reinforced gypsum boards, as shown in Figures 4 and 7. Inside the fire-resistant board frame 1, the side edges of the side fire-resistant boards 9 are fastened with screws to the vertical frame portions 11, and the upper edges of the side fire-resistant boards 9 abut from the inside against the side portions 15 of the upper frame portion 12, which form the vertical surface of the upper frame portion 12, and are fastened with screws to the upper frame portion 12. The lower edges of the side fire-resistant boards 9 are fastened with screws to the ceiling joist 6. Therefore, the entire periphery of the side fire-resistant boards 9 is screwed to the upper frame 12, the vertical frame 11, and the ceiling joist 6, allowing the side fire-resistant boards 9 to demonstrate their fire-resistant performance. In this way, one top fire-resistant board 8 and four side fire-resistant boards 9 form a box-shaped space 7 in the ceiling cavity that is fire-resistant coated.

[0033] As shown in Fig. 6, fall prevention hook 18 has locking portion 19, which is a hook-shaped locking portion formed by bending the upper end of a vertically long thin steel plate at two locations, and flat temporary fixing portion 20 formed to hang down from locking portion 19. Locking portion 19 has a horizontally formed upper flat portion 21, a front hanging portion 22 that hangs vertically from one end of upper flat portion 21, and a rear hanging portion 23 that hangs down from the other end of upper flat portion 21, the lower end of rear hanging portion 23 hanging down as it is to form temporary fixing portion 20. As shown in Fig. 7, locking portion 19 is arranged such that front hanging portion 22 is inserted into and hooked onto fixing hole 17 of upper frame portion 12, and rear hanging portion 23 and temporary fixing portion 20 hang down inside box-shaped space 7 along side fireproof board 9 with upper flat portion 21 abutting against the upper surface of side fireproof board 9.

[0034] As shown in Fig. 9, the equipment fixing frame 10 is a rectangular frame that fits into the box-shaped space 7, and has a vertical, cylindrical outer periphery 24 and an inner extension 25 that extends inward from the lower end of the outer periphery 24. As shown in Figs. 8 and 10, the outer periphery 24 abuts against the temporary fixing portion 20 of the fall prevention hook 18 inside the lower end of the side fireproof board 9, and is suspended from the fall prevention hook 18 with a screw. The height of the equipment fixing frame 10 is adjusted to an appropriate position while temporarily fixed to the fall prevention hook 18, and then, as shown in Figs. 11 and 12, it is fixed to the ceiling joist 6 with a screw.

[0035] A ceiling-mounted device 3 such as a built-in air conditioner or a ventilation fan has a horizontally extending flange 26 at its bottom end. As shown in Figure 13, the ceiling-mounted device 3 is lifted from below into the box-shaped space 7, and the flange 26 is brought into contact with the inner extension 25 of the equipment fixing frame 10 and fixed by fastening screws.

[0036] To install the ceiling-mounted device, first, four vertical frame members 11, four upper frame members 12, and an intermediate frame member 13 are delivered to the construction site and secured together with bolts and nuts to form the fireproof board frame 1, as shown in Figures 1 and 2. Next, as shown in Figure 3, the fireproof board frame 1 is lifted and inserted between the ceiling rafters 6. As this occurs, the fall prevention members 14 formed on the vertical frame members 11 are pressed against the sides of the ceiling rafters 6, elastically deforming, passing between the ceiling rafters 6 and moving above the ceiling rafters 6, expanding. In this way, the fall prevention members 14 abut against the upper surface of the ceiling rafters 6, allowing the fireproof board frame 1 to be temporarily placed while supported on the upper surface of the ceiling rafters 6, facilitating the process of securing the fireproof board frame 1 to the ceiling rafters 6. Then, screws are driven into the vertical frame members 11 to secure the vertical frames to the ceiling rafters 6, thereby securing the fireproof board frame 1.

[0037] Next, as shown in FIGS. 4 and 5 , the top fireproof board 8 is lifted inside the fireproof board frame 1 and abutted against the upper frame portion 12, and screws are driven from below to secure the top fireproof board 8 to the upper frame portion 12. Furthermore, screws are driven from below the top fireproof board 8 along the middle frame portion 13 to secure the top fireproof board 8 to the middle frame portion 13. Then, as shown in FIG. 7 , the side fireproof board 9 is placed vertically below the periphery of the top fireproof board 8, and the side edge of the outer surface of the side fireproof board 9 is abutted against the vertical frame portion 11 of the fireproof board frame 1. At this time, the locking portion 19 of the fall-prevention hook 18 is hooked into the fixing hole 17 formed in the upper frame portion 12 of the fireproof board frame 1 and hooked onto the upper surface of the side fireproof board 9, so that the temporary fixing portion 20 of the fall-prevention hook 18 hangs down along the inner surface of the side fireproof board 9. Then, screws are driven from the inside into both side edges of the side fireproof board 9 to fix the side fireproof board 9 to the vertical frame part 11, screws are driven from the inside into the upper edge of the side fireproof board 9 to fix the side fireproof board 9 to the side part 15 of the upper frame part 12, and screws are driven from the inside into the lower edge of the side fireproof board 9 to fix the side fireproof board 9 to the ceiling joist 6. When the four side fireproof boards 9 are fixed in this way, a box-shaped space 7 that is fireproof-covered with the top fireproof board 8 and side fireproof boards 9 is formed.

[0038] Next, as shown in Figures 8 and 10, the equipment fixing frame 10 is placed at the bottom end of the box-shaped space 7, and the height of the equipment fixing frame 10 is adjusted while the outer periphery 24 of the equipment fixing frame 10 is suspended from the temporary fixing portions 20 of the fall prevention hooks 18 with screws. Then, as shown in Figures 11 and 12, screws are driven in from the inside of the equipment fixing frame 10 to fix the equipment fixing frame 10 to the ceiling joist 6. Thereafter, as shown in Figure 13, the ceiling embedding device 3 is inserted into the box-shaped space 7 from below, the flange 26 of the ceiling embedding device 3 is brought into contact with the inner extension portion 25 of the equipment fixing frame 10, and the screws are fastened, completing the method for installing the ceiling embedding device.

[0039] In this way, the method of installing the ceiling embedded device of this embodiment involves fastening the top fireproof board 8 and the side fireproof board 9 with screws to the fireproof board frame 1 fixed to the ceiling joist 6, thereby forming a fireproof-covered box-shaped space 7 and installing the ceiling embedded device 3, making it possible to easily form a fire prevention line that meets specified standards. Furthermore, since there is no need to install a fire prevention line within the ceiling pocket separately from the ceiling surface, the ceiling surface does not become lower, construction work can be reduced, and the livability of the living space below can be improved.

[0040] It goes without saying that the embodiments of the present invention are not limited to the above-described embodiments, and can be modified as appropriate without departing from the scope of the concept of the present invention. [Industrial Applicability]

[0041] The fire-resistant board frame 1, the installation structure 2 for a ceiling-embedded device, and the installation method for a ceiling-embedded device according to the present invention are suitable as a fire-resistant board frame 1 that serves as a base for a fire-resistant board that forms a box-shaped space 7 in a ceiling for installing, for example, a built-in air conditioner, an installation structure 2 for a ceiling-embedded device using the fire-resistant board frame 1, and an installation method for a ceiling-embedded device. [Explanation of symbols]

[0042] 1 Fireproof board frame 2. Ceiling-mounted device installation structure 3 Ceiling-mounted device 5 rectangular opening 6 Ceiling veranda 7 Box-shaped space 8 Top fireproof board 9 Side fireproof board 11 Vertical frame section 12 Upper frame 13 Middle frame 14 Fall prevention part 18 Fall prevention hook

Claims

1. Four vertical frame portions are fixed to ceiling joists formed around a rectangular opening in the ceiling and extend upward, and are formed at the corners of the rectangular opening; four upper frame portions formed in a rectangular shape so as to connect the upper ends of the vertical frame portions to each other, A fire-resistant board frame characterized in that the vertical frame portion serves as a base for the side edge portions of the side fire-resistant boards that form the sides of a box-shaped space formed above the ceiling, and the upper frame portion serves as a base for the upper edge portions of the side fire-resistant boards and the outer periphery of the upper fire-resistant board that forms the top surface of the box-shaped space.

2. 2. The fireproof board frame according to claim 1, wherein the vertical frame portion and the upper frame portion are detachable from each other.

3. A fire-resistant board frame as described in claim 1 or claim 2, characterized in that an intermediate frame portion that serves as a base for the upper fire-resistant board is installed midway in the longitudinal direction between the two opposing upper frame portions.

4. A fire-resistant board frame as described in any one of claims 1 to 3, characterized in that the vertical frame portion is formed with a fall prevention portion that abuts against the upper surface of the ceiling joist.

5. A fire-resistant board frame as described in any one of claims 1 to 4, characterized in that it further comprises a fall prevention hook having an engaging portion at its upper end that engages with a fixing hole formed in the upper frame portion, hanging down to the inside of the side fire-resistant board, and having a temporary fixing portion at its lower end for suspending an equipment fixing frame that fixes a ceiling-embedded device installed in the box-shaped space.

6. A fire-resistant board frame according to claim 5; an upper fireproof board to which the upper frame portion of the fireproof board frame is attached as a base; a side fireproof board to which the vertical frame portion of the fireproof board frame is attached as a base; the equipment fixing frame is disposed inside the box-shaped space formed by the upper fire-resistant board and the side fire-resistant board and is fixed to the ceiling joist; a ceiling-embedded device disposed in the box-shaped space and fixed to the equipment fixing frame; A ceiling-embedded device installation structure comprising:

7. A method for installing a ceiling-embedded device by constructing the installation structure for a ceiling-embedded device according to claim 6, comprising the steps of: a step of fixing a vertical frame portion of the fireproof board frame to the ceiling joist; a step of fixing the upper fire-resistant board to the upper frame portion of the fire-resistant board frame and fixing the side fire-resistant board to the vertical frame portion; a step of placing the equipment fixing frame inside the box-shaped space formed inside by the top fire-resistant board and the side fire-resistant board and fixing the equipment fixing frame to the ceiling joist; placing the ceiling-embedded device in the box-shaped space and fixing it to the equipment fixing frame; A method for installing a ceiling-embedded device, comprising:

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