JPH08182147A - Fire-resistant structure for cable duct laid along bridge - Google Patents

Abstract

PURPOSE: To effectively suppress the temperature rise of a cable duct with the double-insulating layer of a fire protecting sheet by reducing the thickness of the fire protecting sheet so that the sheet can be easily put on the cable duct laid along a bridge. CONSTITUTION: A fire protecting sheet 19A which is formed by laminating a surface-side composite sheet 21 formed by sticking glass cloth 25 to metallic foil 23, ceramic fiber blanket 27, intermediate metallic foil 29, flame-retardent foam plastic sheet 31, and rear-side composite sheet 33 formed by sticking glass cloth 25 to metallic foil 35 in this order is fitted on a cable duct 13 laid along a bridge 11 with the surface-side composite sheet 21 on the outside.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fireproof structure for a cable pipe mounted on a bridge.

[0002]

2. Description of the Related Art When laying a cable (communication cable, power cable, etc.) along a bridge, a cable pipe is installed along the bridge and the cable is pulled into the cable pipe. Cable pipes are usually installed under the bridge. For this reason, when a bonfire is performed under the bridge, the cable pipe may be directly exposed to the flame. If a steel pipe is used as the cable pipe, the cable pipe itself will not be damaged even if it is hit by a flame, but the flame will raise the temperature of the cable pipe, and the sheath or insulation coating of the cable housed inside Melted down,
An accident such as loss of communication may occur. Further, when a hard PVC (polyvinyl chloride) pipe is used for the cable pipe, the cable pipe itself is damaged when a flame hits, so the internal cable is also easily damaged.

In order to eliminate such an accident, conventionally, rock wool as a heat insulating material is wound around the outer circumference of a cable pipe mounted on a bridge to a thickness of, for example, about 25 mm, and the outer circumference is covered with an iron plate for fire resistance treatment. ing.

[0004]

However, in the conventional fireproof structure, it is difficult to wrap the rock wool thickly around the outer circumference of the cable pipe mounted on the bridge, and the work takes time and cost. there were.

In view of the above problems, an object of the present invention is to provide a fire resistant structure for a bridge-mounted cable tube which is easy to construct and has a reliable heat insulating property.

[0006]

[Means for Solving the Problem and Its Action] One solution according to the present invention is to provide a front composite sheet in which a glass cloth or a carbon non-woven fabric is bonded to a metal foil on the outer periphery of a cable pipe bridged with a bridge, and a ceramic fiber. A blanket, an intermediate composite sheet or an intermediate metal foil in which a metal foil is laminated with flame-retardant paper, glass cloth or carbon nonwoven fabric, a flame-retardant plastic foam sheet, and a metal foil is laminated with flame-retardant paper, glass cloth or carbon nonwoven fabric. The invention is characterized in that a fire-proof sheet formed by laminating a back-side composite sheet or a back-side metal foil in this order is placed with the front-side composite sheet on the outside (Claim 1).

With this structure, the heat-reflecting property of the metal foil of the front composite sheet, the fireproof heat insulating property of the ceramic fiber blanket, the heat-reflecting property of the metal foil or the intermediate metal foil of the intermediate composite sheet, and the flame retardancy. Due to the heat insulating property of the plastic foam sheet and the heat reflectivity of the metal foil or the back metal foil of the back composite sheet, the temperature rise of the cable tube can be effectively suppressed. Therefore, it is possible to prevent the cable in the cable pipe from being damaged by heat. The total thickness of the fireproof sheet is 10
Construction is easy because it can be several mm or less.

Another solution according to the present invention is a front side composite sheet in which a glass cloth or a carbon non-woven fabric is attached to a metal foil on the outer periphery of a cable tube mounted on a bridge.
A heat-expandable reticulated sheet that expands when heated with a flame to form a fire-resistant heat-insulating layer, an intermediate composite sheet or intermediate metal foil in which metal foil is laminated with flame-retardant paper, glass cloth or carbon nonwoven fabric, and flame-retardant plastic. Foam sheet, fire-retardant sheet made by laminating flame-retardant paper, glass cloth or carbon non-woven fabric on metal foil in this order or back-side metal foil, with the front-side composite sheet on the outside. It is a feature (claim 2).

With this structure, when heated by the flame, the heat-expandable reticulated sheet thermally expands between the front composite sheet and the intermediate composite sheet or the intermediate metal foil to form a good fireproof heat insulating layer. In addition, since the flame-retardant plastic foam sheet is sandwiched between the intermediate composite sheet or intermediate metal foil and the backside composite sheet or backside metal foil inside, a heat insulating layer is formed, which effectively increases the temperature of the cable tube. Can be suppressed to. Therefore, it is possible to prevent the cable in the cable pipe from being damaged by heat. Moreover, since the thickness of the entire fire-preventing sheet before the heat-expandable reticulated sheet is thermally expanded can be about 10 mm, the construction is easy.

Yet another solution according to the present invention is to provide a heat-foaming paint on the outer circumference of a cable pipe bridged with a bridge, which foams to form a fire-resistant heat-insulating layer when the fire-resistant net body is heated by a flame. Fireproof net formed by coating, intermediate composite sheet or intermediate metal foil in which metal foil is laminated with flame-retardant paper, glass cloth or carbon nonwoven fabric, flame-retardant plastic foam sheet, metal foil with flame-retardant paper, glass cloth Alternatively, a backside composite sheet obtained by laminating carbon nonwoven fabric or a fireproof sheet obtained by laminating a backside metal foil in this order,
It is characterized in that the front composite sheet is placed on the outside (Claim 3).

With such a structure, when heated by a flame, the heat-foamable fire-resistant paint of the fire-resistant net foams and carbonizes to form a good fire-resistant heat-insulating layer, and the flame-retardant plastic foam inside the layer. Since the heat insulating layer is formed in a state where the sheet is sandwiched between the intermediate composite sheet or the intermediate metal foil and the back side composite sheet or the back side metal foil, the temperature rise of the cable tube can be effectively suppressed. Therefore, it is possible to prevent the cable in the cable pipe from being damaged by heat. Moreover, since the thickness of the entire fireproof sheet before the fireproof net is foamed can be 10 mm or less, the construction is easy.

In the present invention, as the flame-retardant plastic foam sheet, a flame-retardant polyethylene foam sheet or a melamine resin foam sheet can be used. Particularly, the flame-retardant polyethylene foam sheet is suitable because it contains a hydroxide and has an effect of suppressing a temperature rise. Further, as the metal foil, it is preferable to use an aluminum foil which has good heat reflectivity and is lightweight.

[0013]

Embodiments of the present invention will now be described in detail with reference to the drawings. In the figure, 11 is a bridge, 13 is a cable tube made of steel, etc., 15 is a hanging fitting for suspending the cable tube 13 under the bridge 11, and 17 is a cable tube 1
It is a cable pulled into 3.

[Embodiment 1] FIGS. 1 and 2 show an embodiment of the present invention. In this embodiment, the outer circumference of the cable tube 13 mounted on the bridge 11 is covered with a fireproof sheet 19A. This fire protection sheet 19A is made of metal foil 2
Front composite sheet 2 in which glass cloth 25 is attached to 3
1, a ceramic fiber blanket 27, an intermediate metal foil 29, a flame-retardant plastic foam sheet 31, and
A backside composite sheet 33 obtained by laminating a glass cloth 37 on a metal foil 35 is laminated in this order.

As the front composite sheet 21, a metal foil laminated with a carbon nonwoven fabric may be used. Further, as the back side composite sheet 33, it is also possible to use a metal foil laminated with flame-retardant paper or carbon nonwoven fabric. Further, instead of the backside composite sheet 33, a backside metal foil can be used.

The fireproof sheet 19A is covered with the front composite sheet 21 outside. The outer periphery of the fireproof sheet 19A is pressed by the binding member 39 at appropriate intervals so that the seam 41 is not opened. As the binding member 39, a metal tape, a metal wire, a fireproof string, or the like is used. It is preferable that the joints 41 on both side edges of the fire prevention sheet 19A be located above the cable tube 13 as shown in FIG. In this way, the bonfire fired under the bridge 11 does not hit the joint 41, so the joint 41
Even if it is opened a little, the fireproof performance does not deteriorate.

In this embodiment, the ceramic fiber blanket 27 and the flame-retardant plastic foam sheet 31 form a heat insulating layer. Flame-retardant plastic foam sheet 31
Has a lower heat resistance than the ceramic fiber blanket 27, but does not become as hot as the ceramic fiber blanket 27 because it is shielded from the flame by the ceramic fiber blanket 27 and the intermediate metal foil 29. Therefore, even if it has low heat resistance, it is less likely to be thermally damaged.

The fireproof sheet 19A in this embodiment is
As long as the flame-retardant plastic foam sheet 31 is used,
The thickness of the ceramic fiber blanket 27 can be reduced, and the flame-retardant plastic foam sheet 31
Is cheaper than the ceramic fiber blanket 27, so the cost is low as a whole.

If a flame-retardant polyethylene foam sheet is used as the flame-retardant plastic foam sheet 31, the temperature rise when heated may temporarily stall midway, and it may take time for the temperature rise. Therefore, it is particularly preferable. It is considered that this is because the flame-retardant polyethylene foam sheet contains a hydroxide (such as aluminum hydroxide) and generates water when heated.

The seams 41 on both side edges of the fireproof sheet 19A may be abutted as shown in FIG. 2, but may be a superposed one. If you want to overlap,
It is preferable to adopt a configuration as shown in FIG. 4 or FIG. FIG.
4 is a case where the front composite sheet 21 is overlapped with a width wider than other laminates, and in the example of FIG. 4, the front composite sheet 21 and the ceramic fiber blanket 27 are wider than other laminates. This is a case where they are superposed, and the example in FIG. 5 is a case where the front side composite sheet 21, the intermediate metal foil 29, and the back side composite sheet 33 are superposed with a width wider than that of other laminates. In either case, the flame-retardant plastic foam sheet 31 having low heat resistance does not overlap the outside of the ceramic fiber blanket 27 having high heat resistance. In this way, the thickness of the overlapping portion does not have to be so large.

Next, the result of the fire resistance test conducted with the structure of Example 1 will be described. Cable tube 13 has an inner diameter of 75 mm and an outer diameter of 9
It is a 0 mm steel pipe. The cable 17 drawn into the cable tube 13 is a communication cable having a 400-core expanded polyethylene insulation core wire. The metal foil 23 of the front composite sheet 21 is 20 μm thick aluminum foil, the ceramic fiber blanket 27 is 6 mm thick, the intermediate metal foil 29 is 50 μm thick aluminum foil, and the flame-retardant plastic foam sheet 3
Reference numeral 1 is a flame-retardant polyethylene foam sheet having a thickness of 6 mm, and the metal foil 35 of the back side composite sheet 33 is an aluminum foil having a thickness of 20 μm.

A sample having such a constitution is set in a heating furnace for fire resistance test, and the temperature is raised along the second-class heating curve (up to 840 ° C.) of JIS A-1301, and the temperature inside the cable pipe, the surface temperature of the cable, the cable The insulation resistance between cores was measured. As a result, the maximum temperature inside the cable pipe is 139.
C., the maximum temperature of the cable surface was 125.degree. C., the insulation resistance was not deteriorated, and the cable sheath was not abnormal.

In order to protect the fireproof sheet 19A from wind, rain, ultraviolet rays, etc., a metal plate (iron plate, stainless steel plate, etc.) 42 is provided on the outer periphery of the fireproof sheet 19A as shown in FIG.
You should put on. In the illustrated example, the metal plate 42 has a structure in which two semi-cylindrical shapes having fastening pieces on both sides are combined.

[Embodiment 2] FIG. 7 shows another embodiment of the present invention. Although the fireproof sheet 19A in which the intermediate metal foil 29 is interposed between the ceramic fiber blanket 27 and the flame-retardant plastic foam sheet 31 is used in Example 1, this embodiment uses the ceramic fiber blanket 27 and the flame-retardant plastic foam. The fireproof sheet 19B in which the intermediate composite sheet 43 is interposed between the sheets 31 is used. The intermediate composite sheet 43 is made by laminating a flame-retardant paper 47 on a metal foil 45, and the metal foil 45 is laminated with the ceramic fiber blanket 27 side facing. Since the other configurations are the same as those in the first embodiment, the same reference numerals are given to the same portions.

It has been confirmed by a test that with such a configuration, the temperature rise in the cable tube 13 can be suppressed lower than that of the first embodiment. As the intermediate composite sheet 43, a metal foil laminated with glass cloth or carbon nonwoven fabric may be used. Fire protection sheet 1
In order to protect 9B, it is preferable to cover the outer periphery of the fireproof sheet 19B with a metal plate as in the above embodiment.

[Embodiment 3] FIGS. 8 and 9 show an embodiment of the present invention. In this embodiment, a fireproof sheet 19C is put on the outer circumference of a cable tube 13 mounted on a bridge 11. This fireproof sheet 19C is made of metal foil 2
Front composite sheet 2 in which glass cloth 25 is attached to 3
1, a heat-expandable reticulated sheet 49 that expands when heated by a flame to form a fire-resistant heat-insulating layer, a metal foil 45, and a flame-retardant paper 47.
The intermediate composite sheet 43 that is made by sticking together, the flame-retardant plastic foam sheet 31, the metal foil 35, and the carbon nonwoven fabric 5
The back side composite sheet 33 obtained by laminating 1 is laminated in this order.

As the front composite sheet 21, a metal foil laminated with a carbon non-woven fabric may be used. Further, as the intermediate composite sheet 43, a metal foil laminated with glass cloth or carbon non-woven fabric can be used. Further, an intermediate metal foil may be used instead of the intermediate composite sheet 43. Also the back side composite sheet 3
As 3, a metal foil laminated with flame-retardant paper or glass cloth can be used. Further, instead of the backside composite sheet 33, a backside metal foil can be used.

The fireproof sheet 19C is covered with the front composite sheet 21 on the outside, the outer periphery of the fireproof sheet 19C is pressed by the binding members 39 at appropriate intervals, and the joints 41 on both side edges of the fireproof sheet 19C are connected to the cable tube 13. It is similar to the first embodiment in that it is located on the upper side and that the seams 41 on both side edges of the fire protection sheet 19C may be superposed.

The heat-expandable reticulated sheet 49 comprises a rubber-like thin plate 53 (see FIG. 10) prepared by kneading a heat-expandable component such as graphite, perlite, or sodium silicate and a binder such as flame-retardant rubber, and a large number of slits. 55 are formed in the same direction at the same intervals so as to be staggered in the side-by-side direction, and the slitted rubber thin plates 53 are stretched in the direction in which the slits 55 are widened to form a mesh as shown in FIG. As the rubber-like thin plate 53, for example, Dunseal D (trade name) manufactured by Furukawa Techno Material Co., Ltd. can be used. When heated, the Dunseal D expands 10 to 20 times in volume to form a good heat insulating layer.

With the above construction, when heated by a flame, the heat-expandable reticulated sheet 49 thermally expands between the front composite sheet 21 and the intermediate composite sheet 43 to form a good fireproof heat insulating layer. At the same time, the flame-retardant plastic foam sheet 31 is sandwiched between the intermediate composite sheet 43 and the back composite sheet 33 to form the heat insulating layer, so that the temperature rise of the cable tube 13 can be effectively suppressed.
Therefore, the cable 17 in the cable tube 13 can be prevented from being damaged by heat.

The flame-retardant plastic foam sheet 31 has lower heat resistance than the fire resistant heat insulating layer formed by the thermally expandable mesh sheet 49, but the fire resistant heat insulating layer and the intermediate composite sheet 43.
As it is shielded from the flame, it is less likely to suffer thermal damage.

When the seams 41 on both side edges of the fireproof sheet 19C are to be overlapped with each other, it is desirable to have a structure as shown in FIG. 12, FIG. 13 or FIG. The example of FIG. 12 is a case where the front composite sheet 21 is overlapped with a width wider than that of other laminates, and the example of FIG. 13 is the front composite sheet 21.
14 is a case where the intermediate composite sheet 43 and the intermediate composite sheet 43 are overlapped so as to have a width wider than that of the other laminates, and the example in FIG. 14 is the front composite sheet 21, the intermediate composite sheet 43, and the back composite sheet 33.
This is the case where the layers are stacked with a width wider than that of other laminated materials. In any case, flame-retardant plastic foam sheet 31
Are not overlapped on the outside of the heat-expandable mesh sheet 49. In this way, the heat-expandable reticulated sheet 4
The thermal expansion of No. 9 is not hindered, and the thickness of the overlapping portion does not become so large.

Next, the result of the fire resistance test conducted with the structure of Example 3 will be described. The cable tube 13 and the cable 17 are the same as in the first embodiment. The metal foil 23 of the front composite sheet 21 is an aluminum foil having a thickness of 20 μm, the thermally expandable mesh sheet 49 is 2.5 mm in thickness, and the metal foil 45 of the intermediate composite sheet 43 is 2 in thickness.
0 μm aluminum foil, flame-retardant plastic foam sheet 31
Is a flame-retardant polyethylene foam sheet having a thickness of 6 mm, and the metal foil 35 of the back composite sheet 33 is an aluminum foil having a thickness of 20 μm.

As a result of conducting the same fire resistance test as in Example 1 with such a configuration, the maximum temperature inside the cable pipe was 118 ° C. and the maximum temperature on the cable surface was 97 ° C., and there was no deterioration in insulation resistance, and the cable sheath had no deterioration. There was no abnormality.

In order to protect the fireproof sheet 19C from wind, rain, ultraviolet rays, etc., a metal plate (iron plate, stainless steel plate, etc.) 4 is provided on the outer periphery of the fireproof sheet 19C as shown in FIG.
It is good to cover two. In this case, the metal plate 52 is preferably covered with some looseness so as not to hinder the expansion of the heat-expandable reticulated sheet 49.

[Embodiment 4] FIGS. 16 and 17 show an embodiment of the present invention. In this example, the bridge 1
A fireproof sheet 19 is provided on the outer circumference of the cable pipe 13 mounted on
It is covered with D. The fireproof sheet 19D is formed by laminating a heat-foamable fireproof net 57, an intermediate metal foil 29, a flame-retardant plastic foam sheet 31, and a back metal foil 59 in this order.

Instead of the intermediate metal foil 29, it is also possible to use an intermediate composite sheet obtained by laminating flame-retardant paper, glass cloth or carbon nonwoven fabric on the metal foil. Further, instead of the back side metal foil 59, a back side composite sheet obtained by laminating flame-retardant paper, glass cloth or carbon nonwoven fabric on the metal foil can also be used.

The fireproof sheet 19D is covered with the fireproof net 57 on the outer side, the outer periphery of the fireproof sheet 19D is pressed by the fireproof binding members 39 at appropriate intervals, and the joints 41 on both side edges of the fireproof sheet 19D are cable pipes. 1
In the first embodiment, it is possible to position it on the upper side of 3 and that the seams 41 on both side edges of the fire protection sheet 19D may be superposed.
Is the same as

As shown in FIG. 18, the refractory net 57 has a refractory net body 61 made of glass fiber yarn or the like on which a heat-foaming paint 63 which foams and carbonizes by the heat of a flame to form a refractory heat insulating layer. It is applied (manufactured and sold by the German company Herberts). The spacing between the warp yarns and the weft yarns of the net body 61 is about 4 to 6 mm, and the coating amount of the heat-foaming paint 63 is about 600 to 800 g / m ^2, for example. In order to prevent the fireproof net 57 from deteriorating, it is desirable to coat the surface of the fireproof net 57 with weather-resistant paint.

With the above-mentioned structure, the heat-foaming paint of the fireproof net 57 becomes 3 when heated by the flame.
The heat-insulating layer is foamed 0 to 40 times and carbonized to form a good fire-resistant heat-insulating layer, and the flame-retardant plastic foam sheet 31 is sandwiched between the intermediate metal foil 29 and the back-side metal foil 59 inside. Therefore, the temperature rise of the cable pipe 13 can be effectively suppressed. Therefore, the cable 17 in the cable tube 13 can be prevented from being damaged by heat.

Although the flame-retardant plastic foam sheet 31 has lower heat resistance than the fireproof heat insulating layer formed by the fireproof net 57, it is shielded from the flame by the fireproof heat insulating layer and the intermediate metal foil 29, so that thermal damage is prevented. I rarely receive it.

When the seams 41 on both side edges of the fireproof sheet 19C are to be overlapped with each other, it is desirable to have a structure as shown in FIG. In the example of FIG. 19, the heat-foamable refractory net 57 has a width wider than that of other laminates and is overlapped. In this way, the flame-retardant plastic foam sheet 31 does not overlap the outside of the heat-expandable reticulated sheet 49, so that the foaming of the refractory net 57 is not hindered and the overlapping portion is so thick. You don't have to.

Next, the result of the fire resistance test conducted with the structure of Example 4 will be described. The cable tube 13 and the cable 17 are the same as in the first embodiment. The fireproof net 57 has a thickness of about mm, the intermediate metal foil 29 has a thickness of 50 μm of aluminum foil, the flame-retardant plastic foam sheet 31 has a thickness of 5 mm, and the back side metal foil 59 has a thickness of 20 μm. It is aluminum foil. As a result of performing the same fire resistance test as in Example 1 with such a configuration, the maximum temperature inside the cable pipe was 80 ° C., the maximum temperature on the cable surface was 64 ° C., there was no deterioration in insulation resistance, and there was no abnormality in the cable sheath. There wasn't.

In each of the above embodiments, the case where there is one cable pipe has been described, but when two or more cable pipes are juxtaposed, the fireproof sheet is collectively covered on the two or more cable pipes. It can also be configured.

[0045]

As described above, according to the present invention, since the thickness of the fireproof sheet is thin, it can be easily installed on the cable pipe mounted on the bridge, and the temperature rise of the cable pipe can be prevented by using the fireproof sheet. There is an advantage that it can be effectively suppressed by a heavy heat insulating layer.

[Brief description of drawings]

FIG. 1 is a partially cutaway side view showing an embodiment of the invention of claim 1;

2 is a cross-sectional view of the refractory structure of FIG.

FIG. 3 is a cross-sectional view showing a first example of the fireproof structure of FIG. 1 when the seams of the fireproof sheets are superposed.

FIG. 4 is a sectional view showing a second example of the same.

FIG. 5 is a sectional view showing a third example of the same.

6 is a cross-sectional view showing a state in which a metal plate is put on the outer periphery of a fireproof sheet in the fireproof structure of FIG.

FIG. 7 is a partially cutaway side view showing another embodiment of the invention of claim 1;

8 is a partially cutaway side view showing an embodiment of the invention of claim 2. FIG.

9 is a cross-sectional view of the refractory structure of FIG.

FIG. 10 is a plan view of a rubber thin plate with slits used in the fireproof structure of FIG.

11 is a plan view of a heat-expandable reticulated sheet used in the refractory structure of FIG.

FIG. 12 is a cross-sectional view showing a first example of the fire resistant structure of FIG. 8 in which the seams of the fire protection sheets are superposed.

FIG. 13 is a sectional view showing a second example of the same.

FIG. 14 is a sectional view showing a third example of the same.

FIG. 15 is a cross-sectional view showing the fireproof structure of FIG. 8 with a metal plate covering the outer periphery of the fireproof sheet.

FIG. 16 is a partially cutaway side view showing an embodiment of the invention of claim 3;

FIG. 17 is a cross-sectional view of the refractory structure of FIG.

FIG. 18 is a perspective view of a refractory net used in the refractory structure of FIG. 16.

19 is a cross-sectional view showing an example of the fireproof structure of FIG. 16 in which the seams of the fireproof sheets are superposed.

[Explanation of symbols]

 11: Bridge 13: Cable pipe 15: Hanging fitting 17: Cable 19A, 19B, 19C, 19D: Fireproof sheet 21: Front composite sheet 23: Metal foil 25: Glass cloth 27: Ceramic fiber blanket 29: Intermediate metal foil 31: Difficulty Combustible plastic foam sheet 33: Back side composite sheet 35: Metal foil 37: Glass cloth 39: Binding member 41: Seam 43: Intermediate composite sheet 45: Metal foil 47: Flame-retardant paper 49: Thermal expansion mesh sheet 51: Carbon Non-woven fabric 57: Fireproof net 59: Back side metal foil

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B32B 15/04 B 15/14 17/06 H02G 1/06 307 311 Z 315 (72) Inventor sum Junichiro Ki Within 1-8 Higashi-Hachiman, Hiratsuka-shi, Kanagawa, Ltd. Furukawa Techno Material Co., Ltd. (72) Inventor Keikazu Kobayashi 5-23-8 Nishigotanda, Shinagawa-ku, Tokyo Inside Shinsei Denryu Co., Ltd.

Claims (4)

[Claims] 1. A front composite sheet in which a glass cloth or a carbon non-woven fabric is adhered to a metal foil, a ceramic fiber blanket, and a flame retardant paper, a glass cloth or a carbon non-woven fabric are attached to the outer periphery of a cable pipe bridged to a bridge. An intermediate composite sheet or intermediate metal foil laminated together, a flame-retardant plastic foam sheet, and a backside composite sheet or backside metal foil obtained by laminating metal foil with flame-retardant paper, glass cloth or carbon nonwoven fabric in this order. A fireproof structure for a bridge-mounted cable pipe, characterized by covering a fireproof sheet with the front composite sheet on the outside. 2. A front-side composite sheet in which a glass cloth or a carbon non-woven fabric is adhered to a metal foil on the outer circumference of a cable pipe bridged to a bridge, and a thermal expansion property that expands when heated by a flame to form a fireproof heat insulating layer. A mesh sheet, an intermediate composite sheet or an intermediate metal foil in which a metal foil is laminated with flame-retardant paper, glass cloth or carbon nonwoven fabric, a flame-retardant plastic foam sheet, and a metal foil is laminated with flame-retardant paper, glass cloth or carbon nonwoven fabric. A fire resistant structure for a bridge-overlaid cable pipe, characterized in that a fireproof sheet formed by laminating a back side composite sheet or a back side metal foil in this order is placed with the front side composite sheet on the outside. 3. A refractory net formed by coating a heat-foaming paint that foams to form a refractory heat insulating layer on a fire-resistant net body on the outer periphery of a cable pipe mounted on a bridge. , Intermediate composite sheet or intermediate metal foil with metal foil laminated with flame-retardant paper, glass cloth or carbon nonwoven fabric, and backside composite with metal foil laminated with flame-retardant paper, glass cloth or carbon nonwoven fabric A fire resistant structure for a bridge-mounted cable tube, comprising a sheet or a fire prevention sheet formed by laminating a back side metal foil in this order with the front side composite sheet facing outside. 4. The fire resistant structure for a bridge-attached cable pipe according to claim 1 or 2, wherein the fire protection sheet is covered with a metal plate.