JP7657174B2 - Fireproof wrapping structure - Google Patents

Description

The present invention relates to a fire-resistant wrapping structure that improves heat resistance.

In the event of an external fire at a facility such as a power plant, a method is known in which cable trays that house cables or cables in conduits are covered with a wrapping material that has fire resistance in order to prevent damage to the cable facilities (see, for example, Patent Documents 1 to 3).

JP 2015-048405 A JP 2015-171176 A JP 2020-076504 A

In the event of a fire occurring outside the cable equipment, the fire-resistant wrapping material is required to have fire resistance performance that maintains the protected object for a specified time until fire-fighting work can be carried out. The fire-resistant wrapping material covers the cable equipment over a long distance, and is desirably formed to be as lightweight as possible to ensure earthquake resistance. According to the conventional techniques described in Patent Documents 1 to 3, a heat insulating layer is used in the wrapping material to ensure fire resistance. Based on the conventional techniques, if fire resistance performance is to be guaranteed to maintain the protected object for a specified time after the occurrence of a fire, the thickness of the heat insulating layer increases, and there is a risk of the weight of the equipment increasing.

The present invention aims to provide a fire-resistant wrapping structure that can be made lighter while still maintaining fire resistance.

One aspect of the present invention is a heat insulating material having a first surface disposed on the ignition side and made of a first heat insulating material having a first thermal conductivity; a second layer having one surface disposed adjacent to the other surface side of the first layer and made of a second heat insulating material having a second thermal conductivity higher than the first thermal conductivity; and a third layer having one surface disposed adjacent to the other surface side of the second layer and made of a heat absorbing material, wherein the first layer absorbs heat transmitted from an ignition source and reduces the temperature of the first layer to a first predetermined temperature range during the period from 30 minutes to 3 hours after ignition. the second layer is formed to a second layer thickness for lowering the heat transferred in the first predetermined temperature range to a second predetermined temperature range in which the heat absorbing material exerts a heat absorbing effect, and transferring the heat to the third layer; the third layer maintains the heat in the second predetermined temperature range transferred from the second layer at the second predetermined temperature range based on the endothermic reaction of the heat absorbing material; the temperature of the ignition source transitions along a standard heating temperature curve specified in ISO834; the first predetermined temperature range is The heat-resistant wrapping structure has a temperature range of 420°C or higher and 640°C or lower, the second predetermined temperature range is 80°C or higher and 280°C or lower , the thermal conductivity of the first layer in the first predetermined temperature range is 0.02 W/m.K or higher and 0.04 W/m.K or lower, and the thermal conductivity of the second layer in the second predetermined temperature range is 0.03 W/m.K or higher and 0.05 W/m.K or lower .

According to the present invention, since the first layer, which has a lower thermal conductivity than the second layer, is provided on the heating side of the second layer, the second layer thickness of the second layer can be made thinner than when the heating side is formed only with the second layer to have the same level of fire resistance, and the weight can be reduced. Also, according to the present invention, the first layer thickness of the first layer and the second layer thickness of the second layer are formed so that the third layer has a heat absorbing effect, so that fire resistance can be guaranteed.

One aspect of the present invention is a fire-resistant wrapping structure comprising a first layer, one side of which is arranged on the ignition side and formed from a first insulating material having a first thermal conductivity; a second layer, one side of which is arranged adjacent to the other side of the first layer and formed from the same material as the first layer; and a third layer, one side of which is arranged adjacent to the other side of the second layer and formed from a heat absorbing material, wherein, in a state in which a predetermined time has elapsed since ignition, the first layer and the second layer are each formed to a first layer thickness and a second layer thickness, respectively, that reduce the heat transferred from the ignition source to a second predetermined temperature range in which the heat absorbing material exerts its heat absorbing effect and transfer it to the third layer, the third layer maintains the heat in the second predetermined temperature range transferred from the second layer in the second predetermined temperature range based on the endothermic reaction of the heat absorbing material, the temperature of the ignition source progresses along the standard heating temperature curve specified in ISO834, the predetermined time is 3 hours, and the second predetermined temperature range is 300°C or less.

According to the present invention, by forming the second layer from the same material as the first layer, the second layer thickness of the second layer can be made thinner than when it is formed from the second insulating material, and the weight can be reduced.

The present invention may also include a fourth layer, one side of which is adjacent to the other side of the third layer, made of the same material as the second layer, and having a protected object disposed on its other side, and the fourth layer may be formed to a fourth layer thickness that reduces the heat transferred in the second predetermined temperature range to a third predetermined temperature range in which the protected object is maintained, and transfers the heat to the protected object.

According to the present invention, if the temperature of the third layer after heat absorption is higher than the design temperature at which the protected object can be maintained, the fourth layer thickness of the fourth layer can be adjusted to lower the temperature to a third predetermined temperature range at which the protected object can be maintained.

In addition, the first layer thickness and the second layer thickness of the present invention are adjusted so that the second layer transfers heat in the second predetermined temperature range to the third layer during a predetermined fire resistance time after ignition, and the third layer uses up the heat absorption effect, and the fire resistance time may be three hours .

According to the present invention, the third layer uses up its heat absorbing effect during the fire resistance period, so excess heat absorbing material in the third layer can be reduced, making it lighter.

The heat absorbing material of the present invention may be formed from a powder material that separates water based on a chemical reaction when heated and exhibits an endothermic reaction.

According to the present invention, since the heat absorbing material does not normally contain moisture, performance degradation due to drying does not occur, and performance can be continuously maintained over time.

The present invention makes it possible to reduce weight while ensuring fire resistance.

1 is a cross-sectional view showing a configuration of a fire-resistant wrapping structure according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing the configuration of a heat absorbing layer. FIG. 1 is a diagram showing the thermal conductivity of each material. FIG. 4 is an enlarged view showing the thermal conductivity of each material in a low-temperature portion. FIG. 2 is a diagram showing the configuration of a heat absorbing material. FIG. 2 is a cross-sectional view showing the configuration of a fire-resistant wrapping structure that is used for comparison in a performance test. FIG. 11 is a diagram comparing the heat transfer performance of refractory wrapping structures. FIG. 13 is a diagram showing the results of a performance test of the heat absorbing material. FIG. 2 is a cross-sectional view showing the configuration of a fire-resistant wrapping structure that is used for comparison in a performance test. FIG. 13 is a diagram showing the results of a performance test. FIG. 13 is a diagram showing the heat transfer performance of a comparative example of a fire-resistant wrapping structure. FIG. 2 is a cross-sectional view showing the configuration of a fire-resistant wrapping structure that is used for comparison in a performance test. FIG. 13 is a diagram showing the heat transfer performance of a comparative example of a fire-resistant wrapping structure. FIG. 13 is a diagram showing the results of a performance test.

Below, we will explain the fire-resistant wrapping structure according to an embodiment of the present invention, with reference to the drawings.

Facilities such as nuclear power plants are equipped with cable equipment, such as power cables and communication cables, and cable trays that house and support the cables. In the unlikely event of an external fire, the cable equipment requires fire resistance measures to protect the cable equipment, which is the object of protection inside, from fire for a specified period of time (e.g., about three hours) until firefighting work can be carried out. In addition, it is desirable for the fire resistance measures to be lightweight in order to ensure the earthquake resistance of the cable equipment. The fire-resistant wrapping structure of the embodiment has a lightweight configuration while ensuring the fire resistance performance that protects the object of protection.

As shown in Figs. 1 and 2, the fire-resistant wrapping structure 1 has a four-layer structure formed from different types of sheet materials. The fire-resistant wrapping structure 1 is configured to reduce the temperature caused by heat generated on the heated surface on the ignition side to a temperature that can protect the protected object K on the non-heated surface side. The protected object K is, for example, a cable installation. The fire-resistant wrapping structure 1 has, for example, a first layer 2 arranged with one side 2A, which is the heated surface side, exposed to the outside.

The first layer 2 is formed, for example, of a sheet-like first insulating material. The first insulating material is, for example, WDS (registered trademark). The first insulating material is, for example, a material with a low first thermal conductivity (see Figures 3 and 4). The thermal conductivity of WDS is, for example, about 0.04 W/m·K at 800°C. WDS is a high insulating material with low thermal conductivity even in high temperature regions. The first insulating material is, for example, formed of fine fumed silica and a substance that does not transmit infrared rays. The first insulating material has, for example, a micropore structure in which countless fine holes with a diameter of 100 nm or less are formed, which regulates the movement of air molecules. The first insulating material has low elasticity and poor workability compared to the second insulating material (AES) of the second layer 3 described later. One side 2A of the first layer 2 is, for example, arranged to face an ignition source.

A second layer 3 is provided adjacent to the first layer 2 on the other side 2B. The first layer 2 is formed to a first layer thickness that, for example, after a predetermined time has elapsed since ignition, causes the temperature generated by the heat transferred from the ignition source on the one side 2A to drop to a first predetermined temperature range and transfers the temperature to the second layer 3 on the other side 2B. The first layer thickness is, for example, 10 mm.

The second layer 3 has one surface 3A facing the other surface 2B of the first layer 2. The second layer 3 is formed of a sheet-like second insulating material. The second insulating material is, for example, AES (alkaline earth silicate) wool. The second insulating material is, for example, a mineral fiber insulating material having a chemical composition mainly composed of high-purity silica, calcia, and magnesia. The second insulating material may also be formed of bioabsorbable fibers that can be decomposed or absorbed in the body. The second thermal conductivity of the second insulating material is higher than the first thermal conductivity of the first insulating material of the first layer 2. The second insulating material transfers heat faster than the first insulating material (see Figures 3 and 4). The thermal conductivity of AES is higher than that of WDS, especially in the high temperature range (800°C) compared to the low temperature range (400°C).

A third layer 4 is provided on the other surface 3B side of the second layer 3. The second layer 3 is formed to a second layer thickness that reduces the heat transferred by the first layer 2 in the first predetermined temperature range to a second predetermined temperature range in which the heat absorbing material exerts a heat absorbing effect, and transfers the heat to the third layer 4. The second layer thickness is, for example, 13 mm.

The third layer 4 has one surface 4A facing the other surface 3B of the second layer 3. The third layer 4 undergoes a chemical reaction to absorb heat in the second predetermined temperature range transferred from the second layer 3, and exerts a heat absorption effect. The third layer 4 suppresses temperature rise and transmits the heat while maintaining the second predetermined temperature range. The third layer 4 includes, for example, two layers of heat absorbing material 4T (see FIG. 2). The heat absorbing material 4T is formed by accommodating a heat absorbing material 4Q in a storage space formed in a bag shape by a pair of heat insulating sheets 4S. The heat insulating sheets 4S are formed, for example, from a woven fabric made of fire-resistant fibers such as aluminum glass cloth. The pair of heat insulating sheets 4S are provided with perforations 4M for each predetermined rectangular unit, and the heat absorbing material 4T is arranged in a matrix of multiple rectangular small bags 4R (see FIG. 5).

The heat absorbing material 4Q is formed of a powder material that does not contain moisture in order to prevent the heat absorbing effect from decreasing due to drying over time. The heat absorbing material 4Q is, for example, a powder material that separates water based on a chemical reaction when heated and exhibits an endothermic reaction. The heat absorbing material 4Q is, for example, formed of aluminum hydroxide (Al(OH) ₃ ) powder particles. The heat absorbing material 4Q is, for example, a powder crystal with a median particle size of about 10 μm to 100 μm.

Aluminum hydroxide is stable below 200°C, but in the temperature range of 200°C to 350°C, it undergoes intense dehydration decomposition in which water molecules _H2O separate to _{form Al2O3} , and exhibits an endothermic reaction. The heat absorbing material 4T is formed to a layer thickness of, for example, 10 mm. Therefore, the third layer thickness of the third layer 4 is, for example, 20 mm. A fourth layer 5 is provided adjacent to the other surface 4B of the third layer 4. The third layer 4 transfers heat in a second predetermined temperature range to the fourth layer 5.

The fourth layer 5 has one surface 5A facing the other surface 4B of the third layer 4. The other surface 5B of the fourth layer 5 is the non-heated surface facing the object to be protected K. The fourth layer 5 is made of the same material as the second layer 3. The fourth layer 5 is made of, for example, two layers of the same material as the second layer 3. Therefore, the fourth layer thickness is, for example, 26 mm, which is twice the second layer thickness of 13 mm. The fourth layer 5 is formed to a fourth layer thickness that reduces the heat transferred from the third layer 4 in the second predetermined temperature range to a third predetermined temperature range and transfers it to the object to be protected K. The third predetermined temperature range is set, for example, based on a predetermined standard so that the performance of the object to be protected K is maintained.

Next, we will explain the performance test of the fire-resistant wrapping structure 1. In the following performance test, we compare the effect of the position of the third layer 4, which is the heat absorption layer, on the performance.

Figure 6 shows fire-resistant wrapping structure 1 and a fire-resistant wrapping structure for comparison. No. 1 is fire-resistant wrapping structure 1. No. 2 is a comparison object in which the first layer 2, the fourth layer 5, the third layer 4, and the second layer 3 are layered in this order from the heating surface side. In No. 2, the third layer 4, which is a heat absorption layer, is located farther from the heating surface side than in No. 1. No. 3 is a comparison object in which the first layer 2, the third layer 4, the fourth layer 5, and the second layer 3 are layered in this order from the heating surface side. In No. 3, the third layer 4, which is a heat absorption layer, is located closer to the heating surface side than in No. 1. In the performance test, it is set that the passing standard is met when the average temperature rise amount within each fire-resistant wrapping structure (i.e., the non-heating surface) is 139K or less and the maximum value is 181K or less.

Figure 7 shows a comparison of the temperature change in the layer thickness direction when the fire-resistant wrapping structures No. 1 and No. 2 are heated. As shown in the figure, the calculation results of the temperature change in 30-minute increments from 0 hours to 3 hours after heating are shown. The test calculates the temperature change of each layer when heating is performed for a predetermined fire resistance performance time (e.g., 3 hours) that follows the standard heating temperature curve of ISO 834.

In the fire-resistant wrapping structure 1 of No. 1, between 30 minutes and 3 hours, the first layer 2 transfers the heat generated by ignition to the second layer 3 by a first drop in the first predetermined temperature range of about 420°C to 640°C. The second layer 3 transfers the heat transferred from the first layer 2 to the third layer 4 by a second drop in the second predetermined temperature range of about 80°C to 280°C. The third layer 4 transfers the heat transferred from the second layer 3 to the fourth layer 5 by an endothermic reaction in the second predetermined temperature range.

The fourth layer 5 transfers the heat transferred from the third layer 4 to the non-heated surface side by a third drop in a second predetermined temperature range of approximately 20°C to 130°C. As a result, it was confirmed that the average temperature rise of the non-heated surface after three hours was 112K, which met the pass criteria. It was confirmed that the fire-resistant wrapping structure 1 of No. 1 was maintained in the second predetermined temperature range in the third layer 4, which is the heat absorption layer, and thus used up the chemical reaction of the heat absorption material 4Q and fully demonstrated the heat absorption effect, as described below.

In comparison, in the comparative fire-resistant wrapping structure No. 2, between 30 minutes and 3 hours, the first layer 2 of the first layer reduces the heat generated by ignition in a predetermined temperature range of about 480°C to 750°C and transfers it to the fourth layer 5 of the second layer. The fourth layer 5 of the second layer transfers the heat transferred from the first layer 2 of the first layer to the third layer 4 of the third layer by reducing the temperature in a predetermined temperature range of about 50°C to 270°C. The third layer 4 of the third layer transfers the heat transferred from the fourth layer 5 of the second layer to the second layer 3 of the fourth layer in a predetermined temperature range by endothermic reaction.

The fourth layer, the second layer 3, transfers the heat transferred from the third layer 4 of the third layer to the non-heated surface side by lowering the temperature in a second predetermined temperature range of approximately 25°C to 175°C. It was confirmed that the fire-resistant wrapping structure of No. 2 transfers less heat to the third layer 4, which is the heat absorption layer, than No. 1, and that there are parts in the third layer 4 where no chemical reaction occurs in the heat absorption material 4Q, preventing the heat absorption effect from being fully exerted, resulting in a lower fire resistance performance than No. 1. As a result, it was confirmed that No. 2 does not meet the pass criteria, with the average temperature rise of the non-heated surface after three hours having been 155°C.

Referring to the test results of No. 1, the fire-resistant wrapping structure of No. 3 is predicted to have a higher temperature rise than the temperature rise of the third layer 4 of the heat absorption layer in No. 1 when the third layer 4 of the heat absorption layer is adjacent to the first layer 2, and it is predicted that the endothermic reaction of the third layer 4 of the heat absorption layer will be insufficient (the endothermic material will be consumed early and the endothermic reaction will not continue for the specified time). Therefore, the configuration of No. 3 will not be adopted in fire-resistant wrapping structures.

According to the above test results, even if the same material is used, the fire-resistant wrapping structure must be arranged so that the temperature range on the non-heated surface side is kept within the target temperature range after a certain time has elapsed, in which the heat-absorbing material of the third layer 4, which is the heat-absorbing layer, keeps the temperature within the range where it can exert its heat-absorbing effect. According to the test results, it was confirmed that the fire resistance of the No. 1 configuration is higher than that of the No. 2 configuration.

In addition, it is desirable that the third layer 4 of the heat absorbing layer in the fire-resistant wrapping structure 1 has used up its ability to produce a heat absorbing effect when heated within the fire resistance performance time (3 hours). Below, a performance test performed on the two layers of heat absorbing material 4T that make up the third layer 4 is explained. The performance test is, for example, simultaneous differential thermal and thermogravimetry analysis (TG-DTA). Simultaneous differential thermal and thermogravimetry analysis (TG-DTA) is a method in which the temperature of the sample and reference material are changed according to a program, while simultaneously measuring the weight change of the sample (Thermo Gravimetry: TG) and measuring the temperature difference between the sample and reference material (Thermo Gravimetry Analyzer: DTA).

Figure 8 shows the TG-DTA test results for the two layers of heat absorbing material 4T that make up the third layer 4 of the fire-resistant wrapping structure 1. In the figure, the TG curve shows the weight change (wt%) of the sample versus temperature. A decrease in the TG curve indicates a decrease in weight. In the figure, the DTA curve shows the temperature change of the sample based on the thermocouple detection signal (μV) versus temperature. A decrease in the DTA curve indicates an endothermic reaction, and an increase indicates an exothermic reaction. In the test, measurements were performed using (1) a new heat absorbing material 4T, (2) heat absorbing material 4T placed on the heated surface after heating for three hours, and (3) heat absorbing material 4T placed on the non-heated surface after heating for three hours as samples.

As shown in the TG curves, for (1), weight was reduced due to a dehydration reaction. For (2), there was almost no weight reduction, indicating that the performance had been fully utilized. For (3), there was a slight weight reduction, but it was confirmed that the performance had been almost fully utilized. Also, as shown in the DTA curves, for (1), it was confirmed that an endothermic reaction occurred in a specified temperature range. For (2), no endothermic reaction was observed, indicating that the performance had been fully utilized. For (3), there was a slight endothermic reaction observed in a specified temperature range, indicating that the performance had been almost fully utilized.

The test results confirmed that the third layer 4 of the fire-resistant wrapping structure 1 fully exhibits fire resistance during the required fire resistance time (3 hours). In other words, when heat is transferred from the second layer 3 to the third layer 4 within a specified temperature range where the heat absorbing material exerts its heat absorbing effect, the third layer 4 can maintain the specified temperature range and transfer the heat to the fourth layer 5 based on the endothermic reaction of the heat absorbing material, three hours after ignition.

Next, we will explain the performance test that evaluates the effect that differences in the material of the first layer in a fire-resistant wrapping structure have on fire resistance performance.

As shown in FIG. 9, the comparison subjects are fire-resistant wrapping structure 1 No. 1 and fire-resistant wrapping structures No. 4 to No. 7. Fire-resistant wrapping structures No. 4 to No. 7 have a configuration in which the first layer 2 of fire-resistant wrapping structure 1 is formed from the same AES material as the second layer 3, but with different layer thicknesses.

Figure 10 shows the calculation results showing the relationship between the number of each fireproof wrapping structure, the material and thickness of the first layer, and the temperature rise on the unheated side of the fourth layer after three hours of heating. As shown in the figure, in order to ensure the same level of fire resistance performance as fireproof wrapping structure 1 No. 1 with fireproof wrapping structures No. 4 to No. 7, it is necessary to form the thickness of the first layer of AES material to 35-40 mm as in the configurations of No. 6 and No. 7. With fireproof wrapping structures based on the configurations of No. 6 and No. 7, the weight increases as the layer thickness of the AES material increases.

Figure 11 shows the temperature change in the thickness direction when the No. 7 fire-resistant wrapping structure is heated for a specified time. As shown in the figure, in order to ensure the same performance as the No. 1 fire-resistant wrapping structure 1 on the non-heated side, the thickness of the first layer of AES material must be four times thicker than the first layer 2 of the fire-resistant wrapping structure 1. Therefore, according to the No. 1 fire-resistant wrapping structure 1, by using a WDS material for the first layer 2, it is possible to reduce the weight compared to the No. 6 and No. 7 fire-resistant wrapping structures in which the first layer is made of AES material, and the earthquake resistance of the equipment can be improved when applied to the protected object.

Next, we will explain the performance test to evaluate the effect that the difference in the material of the second layer in the fire-resistant wrapping structure has on the fire resistance performance. The fire-resistant wrapping structures No. 1 (fire-resistant wrapping structure 1), No. 8, and No. 9 are compared.

As shown in FIG. 12, the fire-resistant wrapping structure No. 8 has a configuration in which the layer thickness of the second layer 3 of the fire-resistant wrapping structure 1 is changed to 20 mm. The fire-resistant wrapping structure No. 9 has a configuration in which the second layer of the fire-resistant wrapping structure 1 is formed from the same first insulating material as the first layer 2 of the first layer.

Figure 14 shows the calculation results showing the relationship between the number of each fireproof wrapping structure, the material and thickness of the second layer, and the temperature rise on the non-heated side of the fourth layer after three hours of heating. As shown in the figure, in the fireproof wrapping structure No. 8, in which the layer thickness of the second layer 3 is thicker than the layer thickness of the second layer of fireproof wrapping structure No. 1, and when the insulating material of the second layer is changed to WDS like the first layer 2, it was confirmed that the difference in performance is about the same. It was confirmed that the fireproof wrapping structure having the configuration of No. 8 has a thicker layer of the second layer than the fireproof wrapping structure 1 having the configuration of No. 1, and the weight increases. Therefore, if the performance is about the same, the configuration of No. 1, which has a relatively reduced weight, is adopted.

As shown in Figure 13, it was confirmed that the fire-resistant wrapping structure having the configuration of No. 9 has the same performance as the fire-resistant wrapping structure 1 having the configuration of No. 1. The fire-resistant wrapping structure having the configuration of No. 9 has a second layer formed of WDS, which makes it less flexible and less workable than the configuration of No. 1. Therefore, if the performance is comparable, the configuration of No. 1 is adopted in order to prioritize workability.

As described above, the fire-resistant wrapping structure 1 can ensure fire resistance while reducing the weight by forming the first layer 2 to have higher thermal insulation than the second layer 3. The fire-resistant wrapping structure 1 can ensure sufficient heat absorption effect in the third layer 4, which is a heat absorption layer, during the required elapsed time after ignition by adjusting the first layer thickness of the first layer 2 and the second layer thickness of the second layer, which have different thermal conductivities, to predetermined layer thicknesses.

According to the fire-resistant wrapping structure 1, the temperature transferred by the heat generated on the heated surface side during the required elapsed time after ignition can be reduced to a temperature range on the non-heated surface side that can protect the protected object. According to the fire-resistant wrapping structure 1, by adjusting the first layer thickness of the first layer 2 and the second layer thickness of the second layer 3, the second layer 3 can transfer heat in the second predetermined temperature range to the third layer 4, and the third layer 4 can use up its heat absorption effect within a predetermined fire resistance performance time (3 hours) after ignition.

Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope of the invention described in the claims and their equivalents, as well as in the scope and gist of the invention. For example, in the fire-resistant wrapping structure 1, the heat-absorbing material 4Q of the third layer 4 may be formed of a powder material that separates water based on a chemical reaction when heated and exhibits an endothermic reaction, in addition to aluminum hydroxide, and may contain at least one of magnesium hydroxide, calcium hydroxide, calcium sulfate dihydrate, and magnesium sulfate heptahydrate. In addition, a fire-resistant paint may be applied to the heating surface side of the first layer 2 in the fire-resistant wrapping structure 1.

1 Fireproof wrapping structure, 2 1st layer, 2A one side, 2B other side, 3 2nd layer, 3A one side, 3B other side, 4 3rd layer, 4A one side, 4B other side, 4Q Heat absorbing material, 5 4th layer, 5A one side, 5B other side, K Protection target

Claims (4)

a first layer, one side of which is disposed on the ignition side and which is formed of a first insulating material having a first thermal conductivity;
a second layer disposed adjacent to the other side of the first layer and made of a second insulating material having a second thermal conductivity higher than the first thermal conductivity;
a third layer formed of a heat absorbing material and disposed adjacent to the other surface of the second layer;
Between 30 minutes and 3 hours after the fire started,
The first layer is formed to a first thickness for firstly lowering heat transferred from an ignition source to a first predetermined temperature range and transferring the heat to the second layer;
the second layer is formed to a second thickness so as to lower the heat transferred in the first predetermined temperature range to a second predetermined temperature range in which the heat absorbing material exerts a heat absorbing effect, and transfer the heat to the third layer;
the third layer maintains the heat in the second predetermined temperature range transferred from the second layer in the second predetermined temperature range based on an endothermic reaction of the heat absorbing material;
The temperature of the ignition source progresses along the standard heating temperature curve specified in ISO 834,
The first predetermined temperature range is 420° C. or more and 640° C. or less,
The second predetermined temperature range is 80° C. or more and 280° C. or less ,
the thermal conductivity of the first layer in the first predetermined temperature range is equal to or greater than 0.02 W/m K and equal to or less than 0.04 W/m K;
A fire-resistant wrapping structure , wherein the thermal conductivity of the second layer in the second predetermined temperature range is 0.03 W/m·K or more and 0.05 W/m·K or less . a fourth layer, one side of which is provided adjacent to the other side of the third layer, which is made of the same material as the second layer and has an object to be protected arranged on the other side of the fourth layer;
the fourth layer is formed to a fourth layer thickness such that the heat transferred in the second predetermined temperature range is third-times lowered to a third predetermined temperature range in which the protected object is maintained and transferred to the protected object;
The fire-resistant wrapping structure of claim 1 . the first layer thickness and the second layer thickness are adjusted so that the second layer transfers heat in the second predetermined temperature range to the third layer during a predetermined fire resistance time after ignition, and the third layer uses up the heat absorption effect;
The fire resistance performance time is 3 hours.
The fire-resistant wrapping structure according to claim 1 or 2 . The heat absorbing material is formed of a powder material that separates water based on a chemical reaction when heated and exhibits an endothermic reaction.
A fire-resistant wrapping structure according to any one of claims 1 to 3 .

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