Gas-based fire extinguishing systems

Abstract

Based on practical demonstrations, the system releases the necessary amount of extinguishing agent to maintain the concentration of the extinguishing agent within the target area above the flame-extinguishing concentration, thereby providing a gas-based fire extinguishing system that has a high fire extinguishing effect even in fire-target areas with open surfaces that cannot be closed or are difficult to close. [Solution] The amount of fire extinguishing agent released from the fire extinguishing agent release means 2A and 2B is determined based on the sum of a basic release amount necessary to raise the fire extinguishing agent concentration in the fire extinguishing area 3 to a level above the flame extinguishing concentration, which is calculated from the internal volume of the fire extinguishing area 3 without considering the presence of open surfaces 4A and 4B, and a corrected release amount necessary to maintain the fire extinguishing agent concentration in the fire extinguishing area 3 to a level above the flame extinguishing concentration while the fire extinguishing agent flows out from the open surfaces 4A and 4B of the fire extinguishing area 3. The corrected release amount is determined based on the amount of fire extinguishing agent released, which is measured using a model fire extinguishing area having open surfaces 4A and 4B, and is necessary to maintain the fire extinguishing agent concentration in the fire extinguishing area 3 to a level above the flame extinguishing concentration while the fire extinguishing agent flows out from the open surfaces 4A and 4B of the fire extinguishing area 3.

Description

Technical Field

[0001] The present invention relates to a gas fire extinguishing facility that discharges a fire extinguishing agent stored in a fire extinguishing agent storage container into a fire target section and extinguishes the fire by making the concentration of the fire extinguishing agent in the fire target section not less than the extinguishing concentration.

Background Art

[0002] Conventionally, as a gas fire extinguishing facility that discharges a fire extinguishing agent stored in a fire extinguishing agent storage container into a fire target section and extinguishes the fire by making the concentration of the fire extinguishing agent in the fire target section not less than the extinguishing concentration, a gas fire extinguishing agent such as carbon dioxide, halon gas, or nitrogen gas is used as the fire extinguishing agent, and such a facility has been put into practical use.

[0003] By the way, problems related to the destruction of the ozone layer have been raised on a global scale as one of the causes of global warming. Regarding fire extinguishing agents containing halogenated hydrocarbon components such as halon gas, production was stopped in January 1994, and restrictions were imposed.

[0004] To address this, nitrogen gas, noble gases such as argon, perfluoroalkanes with a small ozone depletion coefficient (perfluorobutane (C4F 10 )), hydrofluorocarbons (trifluoromethane (CHF3), heptafluoropropane (C3HF7), or pentafluoroethane (C2HF5)), hydrofluoro halogenoalkanes (iodotrifluoromethane (CF3I)), etc., are each used alone, or a mixed gas in which these are mixed at a predetermined ratio (including the case of mixing other gases such as carbon dioxide).) is used as a fire extinguishing agent (in this specification, these fire extinguishing agents are collectively referred to as "inert gas-based fire extinguishing agents", and a fire extinguishing facility using this inert gas-based fire extinguishing agent is referred to as an "inert gas-based fire extinguishing facility"). Fire extinguishing facilities have been proposed and put into practical use.

[0005] Incidentally, in inert gas fire extinguishing systems that use inert gas-based fire extinguishing agents, it is assumed that people will be present in the area to be extinguished, or there is a possibility that people will be present. Therefore, there are constraints on setting the concentration of the fire extinguishing agent in the area to be extinguished (if the concentration of the fire extinguishing agent is set higher than necessary, there is a risk of health problems for people). Typically, the concentration of the fire extinguishing agent in the area to be extinguished is set to about 1.2 to 1.4 times the flame extinguishing concentration.

[0006] Furthermore, in inert gas-based fire extinguishing systems that use inert gas-based fire extinguishing agents, the fire extinguishing system is designed so that a predetermined amount of fire extinguishing agent, which can raise the concentration of the fire extinguishing agent in the area to be extinguished to approximately 1.2 to 1.4 times the flame extinguishing concentration, is released into the area to be extinguished in a predetermined amount, for example, within 1 minute in the case of nitrogen gas or noble gases such as argon, and in the case of fluorine-based gases, the release into the area to be extinguished is released in a predetermined amount, for example, within 10 seconds in order to suppress the generation of hydrogen fluoride, etc.

[0007] Furthermore, unlike water-based fire extinguishing systems, these gas-based fire extinguishing systems require that the concentration of the extinguishing agent within the area being extinguished be equal to or greater than the flame-extinguishing concentration. Except for special localized discharge systems, gas-based fire extinguishing systems generally work by releasing a fire extinguishing agent into a closed space and ensuring a uniform concentration of the agent within that space. In this case, it is crucial to quickly raise the concentration of the fire extinguishing agent in the space to a constant level and to maintain that level for a certain period of time. Therefore, if there was an open surface (opening) in the area to be extinguished, a closing device was installed on the open surface to close it immediately before releasing the fire extinguishing agent, thereby preventing the fire extinguishing agent from leaking out. Furthermore, conventional fire extinguishing agents consisting of carbon dioxide or halon gas cannot close off the area, or close off the area. In cases where the structure has an open surface that is difficult to extinguish, the amount of extinguishing agent required for the fire-fighting compartment plus an additional amount corresponding to the area of ​​the open surface is released all at once to increase the initial concentration of the extinguishing agent and compensate for the decrease in fire-fighting performance.

[0008] Maintaining the concentration of the fire extinguishing agent is important for inert gas-based fire extinguishing agents, where there are constraints on setting the concentration of the fire extinguishing agent within the area being extinguished. Furthermore, in the case of compressible inert gas-based fire extinguishing agents used in recent years, maintaining the concentration of the fire extinguishing agent is even more important because they have less cooling effect compared to liquefied gas fire extinguishing agents.

[0009] On the other hand, in factory facilities such as paint booths, entrances and exits for goods and ventilation windows are kept open at all times. These open surfaces cannot be closed, or are difficult to close, even when fire extinguishing agents are being discharged. As a result, it is currently difficult to apply gas-based fire extinguishing systems. In other words, when applying gas-based fire extinguishing systems to facilities with open surfaces that cannot be closed or are difficult to close, as described above, the amount of extinguishing agent required for the fire-fighting area plus an additional amount corresponding to the area of ​​the open surface was released all at once. However, with such conventional gas-based fire extinguishing systems, although they have the effect of increasing the initial concentration of the extinguishing agent, they cannot maintain the concentration of the extinguishing agent for a certain period of time. Therefore, although there is no problem if the fire is completely extinguished, if the combustion has reached deep into the combustible material and is smoldering, there is a problem that if the concentration of the extinguishing agent in the fire-fighting area drops even partially below the flame-extinguishing concentration, there is a risk of re-ignition from that point.

[0010] Furthermore, in the case of fire extinguishing systems that use carbon dioxide as a fire extinguishing agent, it is assumed that there are no people in the area to be extinguished, so it is possible to freely set the concentration of the fire extinguishing agent in the area to be extinguished. In contrast, fire extinguishing systems using inert gas-based extinguishing agents sometimes assume the presence of people within the area to be extinguished, which imposes constraints on setting the concentration of the extinguishing agent within that area.

[0011] In view of the problems with the conventional gas-based fire extinguishing systems described above, the applicant previously proposed a gas-based fire extinguishing system that has a high fire extinguishing effect even in facilities with open surfaces that cannot be closed or are difficult to close, by first raising the concentration of the extinguishing agent to a predetermined flame extinguishing concentration through initial discharge, and then supplementing it by discharging additional extinguishing agent equivalent to the amount leaking from the open surface, thereby maintaining the concentration of the extinguishing agent for a certain period of time (see Patent Document 1). [Prior art documents] [Patent Documents]

[0012] [Patent Document 1] Japanese Patent Publication No. 2001-95936 [Overview of the Initiative] [Problems that the invention aims to solve]

[0013] The gas-based fire extinguishing system proposed by the applicant in Patent Document 1 resolves the problems of conventional gas-based fire extinguishing systems by continuously discharging additional fire extinguishing agents after a predetermined amount of fire extinguishing agent has been released to raise the concentration of the fire extinguishing agent in the area to be extinguished to above the flame extinguishing concentration, and then supplementing the amount of fire extinguishing agent that decreases due to leakage from open surfaces in the area to be extinguished by continuously discharging additional fire extinguishing agents. The amount of fire extinguishing agent that has been released is calculated based on the density difference between the mixed gas of fire extinguishing agent and air in the area to be extinguished and the air outside the area to be extinguished, and the amount of fire extinguishing agent to be additionally released is set based on the calculated amount of release, and by discharging the set amount of fire extinguishing agent in addition, the concentration of the fire extinguishing agent in the area to be extinguished is maintained above the flame extinguishing concentration for a predetermined time.

[0014] This invention further improves upon the gas-based fire extinguishing system proposed by the applicant in Patent Document 1, and demonstrates its capabilities. The objective is to provide a gas-based fire extinguishing system that has a high fire extinguishing effect even in fire-fighting areas with open surfaces that cannot be closed or are difficult to close, by releasing the necessary amount of extinguishing agent to maintain the concentration of the extinguishing agent within the fire-fighting area at or above the flame-extinguishing concentration. [Means for solving the problem]

[0015] To achieve the above objective, the gas-based fire extinguishing system of the present invention releases a fire extinguishing agent stored in a fire extinguishing agent storage container into a fire-extinguishing target area having an open surface from a fire extinguishing agent release means, and extinguishes the fire by raising the concentration of the fire extinguishing agent in the fire-extinguishing target area to a concentration equal to or greater than the flame extinguishing concentration, The amount of fire extinguishing agent released from the aforementioned fire extinguishing agent release means is determined based on the sum of a basic release amount, calculated from the internal volume of the fire extinguishing area without considering the presence of open surfaces, which is necessary to raise the fire extinguishing agent concentration within the fire extinguishing area to above the flame extinguishing concentration, and a corrected release amount, which is necessary to maintain the fire extinguishing agent concentration within the fire extinguishing area at or above the flame extinguishing concentration while the fire extinguishing agent flows out from the open surfaces of the fire extinguishing area. The aforementioned corrected discharge amount is determined based on the amount of fire extinguishing agent to be discharged, which is necessary to maintain the concentration of the fire extinguishing agent within the fire extinguishing area at or above the flame extinguishing concentration, when the fire extinguishing agent flows out from the open surface of the fire extinguishing area, as measured using a model fire extinguishing area having an open surface. It is characterized by the following:

[0016] In this case, the corrected discharge amount can be defined as a function of the area of ​​the open surface, specifically as an exponential function of the area of ​​the open surface.

[0017] Furthermore, the corrected discharge amount can be determined based on the amount of fire extinguishing agent required to maintain the concentration of the fire extinguishing agent in the area to be extinguished at or above the flame extinguishing concentration for a predetermined period of time.

[0018] Furthermore, an inert gas-based fire extinguishing agent can be used as the fire extinguishing agent.

[0019] Furthermore, the direction in which the fire extinguishing agent is discharged from the fire extinguishing agent discharge means can be directed, directly or indirectly, to a direction other than that directed towards the open surface.

[0020] Furthermore, the means for dispensing the fire extinguishing agent can consist of a first spray head responsible for dispensing a basic amount of fire extinguishing agent and a second spray head responsible for dispensing a corrected amount of fire extinguishing agent.

[0021] Further, the first injection head and / or the second injection head can be provided with a wind speed suppression means.

[0022] Also, the discharge direction of the fire extinguishing agent discharged from the second injection head can be made planar parallel to the opening surface and / or inward with respect to the opening surface.

[0023] Also, the discharge of the fire extinguishing agent from the second injection head is started simultaneously with or during the discharge of the fire extinguishing agent from the first injection head, and the discharge of the fire extinguishing agent from the second injection head continues even after the discharge of the fire extinguishing agent from the first injection head ends.

[0024] Also, the discharge amount of the fire extinguishing agent from the second injection head can be made to be discharged at a constant flow rate for a predetermined time.

[0025] Also, at least a part of the fire extinguishing agent storage container and piping for supplying the fire extinguishing agent to the first injection head and the second injection head can be provided in common between the first injection head and the second injection head.

[0026] Also, the fire extinguishing agent storage container and piping for supplying the fire extinguishing agent to the first injection head and the second injection head can be provided independently between the first injection head and the second injection head.

[0027] Also, the fire extinguishing target section can be a section having two or more opening surfaces.

[0028] Also, the fire extinguishing target section can be a booth on a line.

[0029] Also, the fire extinguishing target section can be a section surrounded by a casing.

Advantages of the Invention

[0030] According to the gas-based fire extinguishing system of the present invention, even in fire-fighting target compartments that have open surfaces that cannot be closed or are difficult to close, the concentration of the extinguishing agent within the fire-fighting target compartment can be reliably maintained at or above the flame-extinguishing concentration. As a result, regardless of the type of extinguishing agent gas, a gas-based fire extinguishing system can be provided that has a high fire extinguishing effect on fire-fighting target compartments that have open surfaces that cannot be closed or are difficult to close. [Brief explanation of the drawing]

[0031] [Figure 1] This is an explanatory diagram showing one embodiment (two-system piping) of the gas-based fire extinguishing system of the present invention. [Figure 2] This graph shows the relationship between the area of ​​the open surface and the corrected discharge amount of fire extinguishing agent (the amount of fire extinguishing agent required to maintain the concentration at the flame-extinguishing level). [Figure 3] This is an explanatory diagram showing one embodiment (single piping system) of the gas-based fire extinguishing system of the present invention. [Figure 4] This is an explanatory diagram showing one embodiment (single piping system) of the gas-based fire extinguishing system of the present invention. [Figure 5] This is an explanatory diagram showing the discharge direction of the fire extinguishing agent released from the fire extinguishing agent discharge means of the gas-based fire extinguishing system of the present invention. [Figure 6] This is an explanatory diagram showing the discharge direction of the fire extinguishing agent discharged from the fire extinguishing agent discharge means (second spray head) of the gas-based fire extinguishing system of the present invention. [Figure 7] This is an explanatory diagram showing an example of a means for discharging the fire extinguishing agent in the gas-based fire extinguishing system of the present invention. [Figure 8] This is an explanatory diagram showing an example of a means for discharging the fire extinguishing agent in the gas-based fire extinguishing system of the present invention. [Figure 9] This is an explanatory diagram showing an example of a means for discharging the fire extinguishing agent in the gas-based fire extinguishing system of the present invention. [Figure 10] This is an explanatory diagram showing an example of a means for discharging the fire extinguishing agent in the gas-based fire extinguishing system of the present invention. [Figure 11] This graph shows the change in oxygen concentration within the fire-fighting area when fire extinguishing agent is released simultaneously from the first and second injection heads. [Figure 12]This graph shows the change in oxygen concentration within the fire-fighting area when fire extinguishing agent is released from the first spray head. [Figure 13] This graph shows the change in oxygen concentration within the fire-fighting area when fire extinguishing agent is released from the first spray head, which is not equipped with a wind speed suppression mechanism. [Figure 14] This graph shows the change in oxygen concentration within the fire-fighting area when fire extinguishing agent is released from the second spray head after being released from the first spray head. [Figure 15] This is an explanatory diagram showing an example of a fire-fighting target area having an open surface, which is targeted by the gas-based fire extinguishing system of the present invention. [Figure 16] This is an explanatory diagram showing an example of applying the fire extinguishing agent discharge means of the gas-based fire extinguishing system of the present invention to a paint booth. [Figure 17] This is an explanatory diagram showing an example of applying the fire extinguishing agent discharge means of the gas-based fire extinguishing system of the present invention to the burner installation area of ​​a combustion furnace. [Modes for carrying out the invention]

[0032] Hereinafter, embodiments of the gas-based fire extinguishing system of the present invention will be described based on the drawings.

[0033] Figure 1 shows one embodiment of the gas-based fire extinguishing system of the present invention. This gas-based fire extinguishing system extinguishes fires by releasing the extinguishing agent stored in the extinguishing agent storage container 1 (1A, 1B) into the fire-fighting target compartment 3, which has open surfaces 4 (4A, 4B), from the extinguishing agent release means 2A, 2B, thereby increasing the concentration of the extinguishing agent in the fire-fighting target compartment 3 to a level above the flame-extinguishing concentration. The amount of extinguishing agent released from the extinguishing agent release means 2A, 2B is calculated from the internal volume of the fire-fighting target compartment 3 without taking into account the presence of the open surfaces 4 (4A, 4B), and is necessary to increase the concentration of the extinguishing agent in the fire-fighting target compartment 3 to a level above the flame-extinguishing concentration. The amount of discharge is determined based on the sum of the essential basic discharge amount and the corrected discharge amount necessary to maintain the concentration of the fire extinguishing agent in the fire extinguishing area 3 above the flame extinguishing concentration while the fire extinguishing agent is flowing out from the open surfaces 4 (4A, 4B) of the fire extinguishing area 3. The corrected discharge amount is determined based on the amount of fire extinguishing agent discharged, which was measured using a model fire extinguishing area with open surfaces 4 (4A, 4B), and is necessary to maintain the concentration of the fire extinguishing agent in the fire extinguishing area 3 above the flame extinguishing concentration while the fire extinguishing agent is flowing out from the open surfaces 4 (4A, 4B) of the fire extinguishing area 3.

[0034] Figure 2 shows a graph of the amount of fire extinguishing agent (minimum discharge amount) required to maintain the fire extinguishing agent concentration in the fire extinguishing area 3 at the flame extinguishing concentration (1.0 times), measured using a model fire extinguishing area with an open surface 4. The graph here was created by conducting demonstration tests while varying the area of ​​the open surface. The corrected emission amount can be defined as a function of the area of ​​the open surface, specifically as an exponential function of the area of ​​the open surface, and more specifically as an exponential function of the area of ​​the open surface with base Napier's number.

[0035] By the way, Figure 2 is a graph showing the amount of fire extinguishing agent (minimum release amount) required to maintain the concentration of the fire extinguishing agent in the fire-fighting target area 3 at the flame extinguishing concentration (1.0 times). However, when designing an actual gas-based fire extinguishing system, the amount of fire extinguishing agent to be released is determined by considering a safety factor.

[0036] Table 1 shows an example of the amount of extinguishing agent (nitrogen gas) required to maintain the concentration of the extinguishing agent in fire-fighting area 3 at a concentration (1.5 times) that takes into account a safety factor.

[0037] [Table 1]

[0038] The design conditions in Table 1 are as follows: • Method of releasing fire extinguishing agent It consists of a first spray head 2A, which is mainly responsible for discharging the basic amount of fire extinguishing agent (discharging the fire extinguishing agent toward the center of the fire-fighting target area 3), and a second spray head 2B, which is mainly responsible for discharging the corrected amount of fire extinguishing agent (discharging the fire extinguishing agent in a planar shape parallel to the open surfaces 4 (4A, 4B) of the fire-fighting target area 3 (and / or inward relative to the open surfaces). The number and location of the first injection head 2A and the second injection head 2B can be set according to the shape of the fire-fighting target compartment 3 and the shape of the open surfaces 4 (4A, 4B), etc. ·Piping method Two piping systems: Fire extinguishing agent storage containers 1A, 1B and piping 5A, 5B, which supply fire extinguishing agent to the first injection head 2A and the second injection head 2B, are provided independently for the first injection head 2A and the second injection head 2B (Figure 1). • Amount and duration of release of fire extinguishing agent (nitrogen gas) First spray head 2A: Discharges the basic discharge amount + corrected discharge amount of fire extinguishing agent for 0.5 minutes (considering the safety factor, the corrected discharge amount of fire extinguishing agent is added and discharged). Second spray head 2B: Discharges a corrected amount of fire extinguishing agent for 5 minutes. • The time required to maintain the fire extinguishing agent concentration in fire-fighting area 3 at or above the flame-extinguishing concentration. More than 5 minutes

[0039] Incidentally, while the design conditions in Table 1 show an example with a two-system piping arrangement, the piping arrangement can also be modified as shown in Figure 3, so that the fire extinguishing agent storage container 1 and piping 5 (at least a part of it) that supply the fire extinguishing agent to the first spray head 2A and the second spray head 2B are shared by both the first spray head 2A and the second spray head 2B. Table 2 shows examples of formulas for calculating the amount of fire extinguishing agent to be released in the case of a single-system piping and a double-system piping.

[0040] [Table 2]

[0041] While a single-system piping system has the advantage of simplifying the installation structure of the fire extinguishing agent storage container 1 and piping 5 compared to a two-system piping system, it has the disadvantage of making it difficult to fine-tune the amount of fire extinguishing agent released, which can lead to an increase in the amount of fire extinguishing agent released and thus a larger amount of fire extinguishing agent required. To overcome this drawback, for example, a non-return valve can be installed in the piping route, as shown in Figure 4.

[0042] By the way, under the design conditions in Table 1, the corrected discharge amount of fire extinguishing agent from the second injection head 2B is discharged for 5 minutes. By releasing the extinguishing agent, the time required to maintain the concentration of the extinguishing agent in the fire-fighting target area 3 above the flame-extinguishing concentration is 5 minutes or more. However, this time can be set to any length of time from a few minutes to 10 minutes or more by determining the corrected release amount based on the amount of extinguishing agent required to maintain the concentration of the extinguishing agent in the fire-fighting target area 3 above the flame-extinguishing concentration for a predetermined time.

[0043] Furthermore, the amount of fire extinguishing agent discharged from the second spray head 2B can be set to be discharged at a constant flow rate for a predetermined period of time, for example, a set time of several minutes to 10 minutes or more.

[0044] Furthermore, while nitrogen gas was used as the fire extinguishing agent in the design conditions shown in Table 1, inert gas-based fire extinguishing agents such as nitrogen gas can be used.

[0045] The direction in which the fire extinguishing agent is discharged from the first spray head 2A and the second spray head 2B, which are means for discharging the fire extinguishing agent, is directed in a direction other than that which is directed towards the open surfaces 4 (4A, 4B), both directly and indirectly (by colliding with obstacles), so that the discharged fire extinguishing agent does not leave the open surfaces 4 (4A, 4B) of the fire-fighting target area 3 but remains within the fire-fighting target area 3. Specifically, as shown in Figure 5(a), the fire extinguishing agent is discharged from the first spray head 2A so as to be directed toward the center of the fire-fighting area 3, or, as shown in Figure 5(b), if there is an obstacle in the center of the fire-fighting area 3, the fire extinguishing agent is discharged from the first spray head 2A so as to form a plane parallel to the obstacle. Furthermore, the second spray head 2B can be configured to discharge the fire extinguishing agent in a manner parallel to the open surfaces 4 (4A, 4B) of the fire-extinguishing compartment 3, as shown in Figure 1, or to discharge the fire extinguishing agent inward relative to the open surfaces 4 of the fire-extinguishing compartment 3, as shown in Figure 3.

[0046] In addition to the methods shown in Figures 1 and 3, the discharge pattern of the fire extinguishing agent from the second spray head 2B, which is a means for discharging the fire extinguishing agent, can also be configured as shown in Figure 6(a), where the fire extinguishing agent is discharged from multiple parallel second spray heads 2B in a direction parallel to the open surface 4, or as shown in Figure 6(b), where the fire extinguishing agent is discharged from the second spray head 2B in a radial direction parallel to the open surface 4.

[0047] The first spray head 2A and / or the second spray head 2B, which are means for discharging the fire extinguishing agent, may be equipped with a wind speed suppression means. Specifically, as shown in Figure 7(a), a deflector (deflection member) 21 is provided at the discharge port of the fire extinguishing agent of the spray head 2 to give the fire extinguishing agent discharged from the spray head 2 a flow component perpendicular to the discharge direction, or as shown in Figure 7(b), the discharge direction of the fire extinguishing agent from the spray head 2 is made perpendicular to the direction of supply to the fire extinguishing agent, and orifice members 22 and 23 with orifices 22a and 23a formed thereon, and a block-shaped porous material 24 through which gas can flow is provided in the flow path of the fire extinguishing agent of the spray head 2, which is disposed at the outlet of the orifice 23a of the orifice member 23. Here, the porous material 24 can be made of a homogeneous material as a whole, or it can be made of a material that is modified in the direction in which gas flows, more specifically, a material that is made smaller in the direction in which gas flows, for example, it can be made of a material in which the diameter of the voids of the downstream second member 24b is smaller than the diameter of the voids of the upstream first member 24a.

[0048] Furthermore, when the fire extinguishing agent is to be discharged in a directional manner rather than radially, as shown in Figures 8(a1) to (a2), the flow path of the fire extinguishing agent in the spray head 2 is made of an orifice tube 25 with an orifice 25a formed thereon, and a long, block-shaped porous material 24 through which gas can flow is provided at the outlet, or as shown in Figure 8(b), the flow path of the fire extinguishing agent in the spray head 2 is made of a long, block-shaped porous material 26, and a plate-shaped orifice member 27 with an orifice 27a formed thereon is provided in the flow path of the fire extinguishing agent, and a block through which gas can flow is provided at its outlet. A porous material 24 with a specific shape may be provided.

[0049] In addition, as shown in Figures 9(a) to (e), the flow path of the fire extinguishing agent in the spray head 2 is provided with an orifice member 22 having an orifice 22a and a block-shaped porous material 24 through which gas can flow, which is placed at its outlet. Furthermore, a part of the outer surface of the block-shaped porous material 24 (for example, in the range of 180° to 270°) is covered with a cover 28. Also, as shown in Figures 10(a) to (c), the discharge direction of the fire extinguishing agent from the spray head 2 is directed towards the fire extinguishing agent. The direction is perpendicular to the supply direction, and orifice members 22 and 23 with orifices 22a and 23a formed therein (the orifice 23a is formed on a part of the circumferential surface of the cylindrical orifice member 23 (for example, in the range of 90° to 180°)) and a block-shaped porous material 24 through which gas can flow is provided at the outlet of the orifice 23a of the orifice member 23.

[0050] The design conditions in Table 1 stipulate that the discharge of the fire extinguishing agent from the second spray head 2B begins simultaneously with the discharge of the fire extinguishing agent from the first spray head 2A, and that the discharge of the fire extinguishing agent from the second spray head 2B continues for a predetermined time (5 minutes; this time can be set to any time from a few minutes to 10 minutes or more) even after the discharge of the fire extinguishing agent from the first spray head 2A has finished. However, it is also possible to introduce a time lag during the discharge of the fire extinguishing agent from the first spray head 2A so that the discharge of the fire extinguishing agent from the second spray head 2B begins. Figure 11 shows the change in oxygen concentration within fire-fighting area 3 when the fire extinguishing agent is released under the design conditions in Table 1. In the case of Figure 11, when only the first injection head 2A shown in Figure 12 is used (without discharge of fire extinguishing agent from the second injection head 2B), the increase in oxygen concentration within the fire-fighting target area 3 is more gradual (the fire extinguishing agent concentration within the fire-fighting target area 3 can be stably maintained above the flame extinguishing concentration). This is in comparison to the case where the first injection head 2A in Figure 12 is not equipped with a wind speed suppression means, as shown in Figure 13, and the case where the discharge of fire extinguishing agent from the second injection head 2B begins after the discharge of fire extinguishing agent from the first injection head 2A, as shown in Figure 14.

[0051] The fire-fighting compartment 3 having open surfaces 4 that are targeted by the gas-based fire extinguishing system of the present invention is not particularly restricted, and fire-fighting compartment 3 having open surfaces 4 of various shapes and numbers (two or more surfaces) as shown in Figure 15 is targeted. Specific examples of fire-extinguishing areas 3 targeted by the gas-based fire extinguishing system of the present invention include booths on a line (manufacturing line) as shown in Figure 16 (for example, a paint booth), and areas enclosed by a casing 6 as shown in Figure 17 (for example, an area where burners such as combustion furnaces are installed). Furthermore, the corrected discharge amount in such a fire-extinguishing target compartment 3 can be determined based on the amount of fire extinguishing agent discharged, which is required to maintain the fire extinguishing agent concentration in the fire-extinguishing target compartment 3 at or above the flame extinguishing concentration, when the fire extinguishing agent flows out from the open surface 4 of the fire-extinguishing target compartment 3, as measured using a model fire-extinguishing target compartment having an open surface 4.

[0052] This gas-based fire extinguishing system ensures that even in fire-fighting target compartments 3 with open surfaces 4 (4A, 4B) that cannot be closed or are difficult to close, the concentration of the extinguishing agent within the fire-fighting target compartment 3 can be reliably maintained at or above the flame-extinguishing concentration. As a result, regardless of the type of extinguishing agent gas, it is possible to provide a gas-based fire extinguishing system that has a high fire extinguishing effect on fire-fighting target compartments with open surfaces 4 (4A, 4B) that cannot be closed or are difficult to close.

[0053] The gas-based fire extinguishing system of the present invention has been described above based on its embodiments. However, the present invention is not limited to the configuration described in the above embodiments, and its configuration can be modified as appropriate without departing from the spirit of the invention, such as by appropriately combining the configurations described in each embodiment. [Industrial applicability]

[0054] The gas-based fire extinguishing system of the present invention, based on practical experience, releases the necessary amount of extinguishing agent to maintain the concentration of the extinguishing agent within the fire-extinguishing area above the flame-extinguishing concentration. This allows for the provision of a gas-based fire extinguishing system with a high fire extinguishing effect even in fire-extinguishing areas with open surfaces that cannot be closed or are difficult to close. Therefore, it can be suitably used in applications where an inert gas-based extinguishing agent such as nitrogen gas is used as the extinguishing agent gas for fire-extinguishing areas with open surfaces that cannot be closed or are difficult to close. [Explanation of Symbols]

[0055] 1. Fire extinguishing agent storage container 1A Fire extinguishing agent storage container (for the first spray head) 1B Fire extinguishing agent storage container (for the second spray head) 2. Means for dispensing fire extinguishing agent (spray head) 21. Deflector (deflection member) 22 Orifice Member 22a Orifice 23 Orifice component 23a Orifice 24 Porous materials 24a First member 24b Second Member 25 Orifice tubes 25a Orifice 26 Porous materials 27 Orifice component 27a Orifice 2A Fire extinguishing agent discharge means (first spray head) 2B Fire extinguishing agent discharge means (second spray head) 3. Firefighting Area 4, 4A, 4B open side 5 Piping 5A Piping (for the first injection head) 5B Piping (for the second injection head)

Claims

1. In a gas-based fire extinguishing system that extinguishes a fire by releasing a fire extinguishing agent stored in a fire extinguishing agent storage container into a fire-fighting target area having an open surface from a fire extinguishing agent release means, thereby extinguishing a fire by raising the concentration of the fire extinguishing agent in the fire-fighting target area to a concentration equal to or greater than the flame extinguishing concentration, The amount of fire extinguishing agent released from the aforementioned fire extinguishing agent release means is determined based on the sum of a basic release amount, calculated from the internal volume of the fire extinguishing area without considering the presence of open surfaces, which is necessary to raise the fire extinguishing agent concentration within the fire extinguishing area to above the flame extinguishing concentration, and a corrected release amount, which is necessary to maintain the fire extinguishing agent concentration within the fire extinguishing area at or above the flame extinguishing concentration while the fire extinguishing agent flows out from the open surfaces of the fire extinguishing area. The aforementioned corrected discharge amount is determined based on the amount of fire extinguishing agent to be discharged, which is necessary to maintain the concentration of the fire extinguishing agent within the fire extinguishing area at or above the flame extinguishing concentration, when the fire extinguishing agent flows out from the open surface of the fire extinguishing area, as measured using a model fire extinguishing area having an open surface. A gas-based fire extinguishing system characterized by the following features.

2. The gas-based fire extinguishing system according to claim 1, characterized in that the corrected discharge amount is defined as a function of the area of ​​the open surface.

3. The gas-based fire extinguishing system according to claim 2, characterized in that the function is defined by an exponential function of the area of ​​the open surface.

4. The gas-based fire extinguishing system according to claim 1, 2, or 3, characterized in that the corrected discharge amount is determined based on the amount of fire extinguishing agent discharged necessary to maintain the concentration of the fire extinguishing agent in the fire-extinguishing area above the flame extinguishing concentration for a predetermined time.

5. The gas-based fire extinguishing system according to claim 1, 2, or 3, characterized in that the fire extinguishing agent is an inert gas-based fire extinguishing agent.

6. The gas-based fire extinguishing system according to claim 1, 2, or 3, characterized in that the direction of discharge of the fire extinguishing agent from the fire extinguishing agent discharge means is directed, directly or indirectly, to a direction other than the direction directed toward the open surface.

7. The gas-based fire extinguishing system according to claim 1, 2, or 3, characterized in that the means for discharging the fire extinguishing agent comprises a first spray head responsible for discharging a basic discharge amount of fire extinguishing agent and a second spray head responsible for discharging a corrected discharge amount of fire extinguishing agent.

8. The gas-based fire extinguishing system according to claim 7, characterized in that the first injection head and / or the second injection head are equipped with wind speed suppression means.

9. The gas-based fire extinguishing system according to claim 7 or 8, characterized in that the direction of discharge of the fire extinguishing agent released from the second spray head is planar, parallel to the open surface, and / or inward relative to the open surface.

10. The gas-based fire extinguishing system according to claim 7 or 8, characterized in that the discharge of the fire extinguishing agent from the second spray head is started simultaneously with or during the discharge of the fire extinguishing agent from the first spray head, and the discharge of the fire extinguishing agent from the second spray head continues even after the discharge of the fire extinguishing agent from the first spray head has finished.

11. The gas-based fire extinguishing system according to claim 7 or 8, characterized in that the amount of fire extinguishing agent discharged from the second spray head is discharged at a constant flow rate for a predetermined time.

12. The gas-based fire extinguishing system according to claim 7 or 8, characterized in that at least a portion of the fire extinguishing agent storage container and piping that supply the fire extinguishing agent to the first and second spray heads are shared by the first and second spray heads.

13. The gas-based fire extinguishing system according to claim 7 or 8, characterized in that the fire extinguishing agent storage container and piping for supplying the fire extinguishing agent to the first and second spray heads are provided independently for the first and second spray heads.

14. The gas-based fire extinguishing system according to claim 1, 2, or 3, characterized in that the fire-extinguishing target compartment is a compartment having two or more open surfaces.

15. The gas-based fire extinguishing system according to claim 1, 2, or 3, characterized in that the fire extinguishing target area is a booth located on a line.

16. The gas-based fire extinguishing system according to claim 1, 2, or 3, characterized in that the fire-extinguishing target area is an area enclosed by a casing.

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