JPH07204288A - Fireproofing structure for combustible cable - Google Patents

Abstract

PURPOSE:To prolong a time for maintaining function as a cable in such state as exposed to a flame by winding a fire protection net formed out of a fire resistant net body coated with thermally foaming paint, around a combustible cable via a gap, at the time of winding the net around the combustible cable for fireproofing treatment. CONSTITUTION:A fire protection net 1 is formed out of a net body knitted from fire resistant yarn, for example, glass fiber yarn, and thermally foaming paint applied to thereto. Also, a cord 5 is spirally wound at a large pitch around the external surface of a combustible cable 4 such as a telecommunications cable and, then, the net 1 is wound around the cord 5. As a result, a gap 6 corresponding to the thickness of the cord 5 is formed between the cable 4 and the net 1. According to this construction, the gap 6 acts as an insulation layer, and the foam of the net 1 grows not only externally, but also internally (toward cable side). Thus, a foamed layer of high insulation quality can be provided, and the temperature rise and combustion of a cable inside can be thereby restrained.

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 flammable cable.

[0002]

2. Description of the Related Art Cables such as telecommunication cables, optical communication cables and electric power cables generally use a flammable material such as polyethylene for an insulator, a protective coating or a sheath, so that when a fire occurs, the longitudinal direction of There is a risk of spreading fire.

As a means for preventing the spread of flammable cables, a method of winding a heat-foaming fireproof net around the cables has recently been studied. This fireproof net is made by applying a heat-foaming paint to the net body made of a fireproof material such as glass fiber thread by the dipping method (manufactured and sold by Herberts GmbH in Germany). The heat-foaming paint foams 30 to 40 times when heated by a flame and carbonizes to form a good heat insulating layer.

[0004]

[Problems to be Solved by the Invention] According to the result of conducting a fire resistance test (850 ° C x 20 minutes) specified in IEEE383 by winding this fireproof net around a flammable cable, the fireproof net is wrapped around a flammable cable. It was confirmed that it was effective in preventing the spread of fire. However, it turned out that the insulation resistance between the insulation core wires decreased within 10 minutes after the flame was applied and the function as a cable (communication function, etc.) could not be maintained simply by winding the fire protection net. did.

In the case of fire protection of a cable, it is not enough to simply have a fire spread prevention effect, and it is required that the function as a cable can be maintained for a certain period of time (usually 20 minutes or more) while being exposed to a flame. To be done.

[0006]

DISCLOSURE OF THE INVENTION The present invention provides a fireproof structure for a flammable cable which solves the above-mentioned problems, and has a structure that is suitable for a flammable cable and a fireproof net body. A fire-proof net formed by applying a heat-foaming paint is wrapped around and subjected to a fire-proof treatment, characterized in that the fire-proof net is wrapped around with a gap between the flammable cable and the flammable cable. is there.

[0007]

[Function] When a space is provided between the flammable cable and the heat-foaming fireproof net, this space serves as a heat insulating layer and the foam of the fireproof net grows not only on the outer surface side but also on the inner surface side (cable side). Therefore, a foamed layer having a better heat insulating property can be obtained. As a result, the temperature rise and combustion of the internal cable are suppressed, and the time during which the function as the cable can be maintained in the state of being exposed to the flame can be lengthened.

[0008]

Embodiments of the present invention will now be described in detail with reference to the drawings. 1 and 2 show an embodiment of the fireproofing structure of the present invention, and FIG. 3 shows a fireproof net used therefor.

First, the fireproof net will be described with reference to FIG. The fireproof net 1 is formed by applying a heat-foaming paint 3 to a net body 2 knitted with a fire resistant yarn such as a glass fiber yarn.
The application of the heat-foaming paint 3 is performed by dipping the net body 2 in a solution of the heat-foaming paint, then pulling it up and drying it. The spacing between the warp threads and the weft threads of the net body 2 is, for example, about 4 to 6 mm, and the coating amount of the heat-foaming paint 3 is, for example, about 600 to 800 g / m ² . Thermal foaming paint 3
When heated by a flame, foams 30 to 40 times and carbonizes to form a good heat insulating layer. The holes in the mesh are completely filled with foam. The composition of the heat-foamable paint 3 is solvent-based, and is 25-30% of solvent, 15-20% of resin component, 10-20% of foaming component, and 30-40% of other (pigment, etc.). Water, 30-40%, resin component 10-20%, foaming component 25
~ 45%, other (pigments, etc.) 10 to 15%.

In the fireproof structure shown in FIGS. 1 and 2, a cord 5 is spirally wound around a flammable cable 4 such as a communication cable at a long pitch, and the fireproof net 1 shown in FIG. 3 is wound on it. It is a thing. As a result, a space 6 corresponding to the thickness of the string 5 is formed between the flammable cable 4 and the fireproof net 1.

The cord 5 serves as a spacer for keeping the distance between the cable 4 and the fireproof net 1. Therefore, any material may be used as long as it does not melt or burn at the temperature at which the fireproof net 1 foams, and for example, a glass fiber string can be used. Further, the string 5 may be foamed by itself like the fireproof net 1. For example, a cord-shaped core material made of glass fiber or the like coated with a heat-foaming paint can be used.

The string 5 may be wound in a non-helical manner, for example, may be wound in an annular shape at an appropriate interval in the longitudinal direction of the cable. Further, the means for providing the gap between the flammable cable 4 and the fireproof net 1 does not have to be a string. For example, protrusions may be formed on one side of the fireproof net at appropriate intervals, and the protrusions may be placed on the inside of the cable. The void can also be formed by winding.

Next, the results of the fire resistance test of the fire protection structure shown in FIGS. 1 and 2 will be described. Fire resistance test is IEEE383
According to the regulations, a fireproof cable is set in a vertical open tray and the flame of a gas burner is applied for 20 minutes. The test cable is a polyethylene insulation / polyethylene sheath communication cable (CCP / P 0.5 × 100).
Pair). Insulation resistance was measured for the insulated core wire pair in the test cable in order to investigate the maintenance of the communication function. As a result, while the flame is hit (20 minutes), the flame rises due to the combustion of organic matter in the fire protection net, but when the flame of the burner stops after 20 minutes, the flame disappears immediately and it is possible to prevent the spread of fire. Was confirmed. It was also found that the insulation resistance did not decrease at all even after 20 minutes had passed since the application of the flame, and the cable function could be sufficiently maintained.

[0014]

As described above, according to the present invention, there is an advantage that the fireproofing process including the prevention of the spread of flammable cable and the function maintenance can be easily performed by using the heat-foaming fireproof net.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a fireproofing structure for a flammable cable according to the present invention.

FIG. 2 is a perspective view showing the fire protection structure of FIG. 1 in a stripped state.

3 is a perspective view of a fireproof net used in the fireproofing structure of FIG. 1. FIG.

[Explanation of symbols]

 1: Fireproof net 2: Net body 3: Thermo-foaming paint 4: Flammable cable 5: String 6: Void

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Junichiro Wake, 5-18 Higashihachiman, Hiratsuka City, Kanagawa Prefecture Furukawa Techno Material Co., Ltd. (72) Inventor Keiwa Kobayashi 5-23, Nishigotanda, Shinagawa-ku, Tokyo No. 8 In stock company Shinsei Denshi

Claims (1)

[Claims] 1. A flammable cable, which is fire-proofed by winding a fire-resistant net made by applying a heat-foamable paint to a fire-resistant net body, wherein the fire-proof net is provided between the flammable cable and the flammable cable. A fireproof structure for flammable cables, characterized by being wound around with a gap.