JP7058554B2 - Fire extinguishing equipment - Google Patents

Description

The present invention relates to fire extinguishing equipment such as sprinkler equipment and foam fire extinguishing equipment.

In fire extinguishing equipment such as sprinkler equipment and foam fire extinguishing equipment, a water flow detection device is installed on the pipe leading from the water source to the sprinkler head (or foam head). The water flow detector has a check valve structure and allows only one-way water flow from the water source to the sprinkler head. In the secondary side piping where the sprinkler head is installed, the water filled inside expands and contracts due to the seasonal temperature difference. Especially in summer, the water in the secondary piping expands and the pressure rises, which may damage the sprinkler head. Further, in winter, when the volume expands due to freezing of water in the secondary side pipe, the water in the pipe is compressed and the pressure rises, which may cause the same damage as described above.

On the other hand, in Patent Document 1, a bypass flow path that bypasses the primary side and the secondary side of the water flow detection device is installed, and a differential pressure valve is installed on the bypass flow path. The differential pressure valve opens when the pressure on the secondary side becomes higher than the pressure on the primary side by a predetermined value or more, and allows water to escape from the secondary side pipe to the primary side pipe to prevent damage to the sprinkler head.

Japanese Unexamined Patent Publication No. 8-131574

When a fire breaks out in the fire extinguishing system of FIG. 1 provided with a relief mechanism such as the differential pressure valve, the sprinkler head S operates and the water in the secondary side pipe 2a is discharged. As a result, the pressure of the secondary side pipe 2a is lower than the pressure of the primary side pipe 1, the valve body of the water flow detection device 3a is opened, and the operation signal is output. When the flow water detection device 3a is opened, the water of the primary side pipe 1 is supplied to the secondary side pipe 2a, and the pressure of the primary side pipe 1 decreases.

Since the primary side pipe 1 is also connected to the water flow detection devices 3b and 3c of the other system, it is between the primary side pipe 1 and the secondary side pipes 2b and 2c in the relief valves 4b and 4c of the system in which no fire has occurred. A differential pressure is generated. When this differential pressure becomes more than a predetermined value, the relief valves 4b and 4c of the non-fire system are opened, and water flows from the secondary side pipes 2b and 2c of the non-fire system to the primary side pipe 1.

By supplying water from the secondary side pipes 2b and 2c of the non-fire system to the primary side pipe 1, the pressure drop of the primary side pipe 1 becomes slow, and the pump start switch 5 installed in the primary side pipe 1 is activated. It may take some time to reach the specified pressure to operate. As a result, although the sprinkler head S operates, there is a risk that sufficient water supply will not be performed and the initial fire extinguishing will be hindered.

Therefore, in view of the above problems, it is an object of the present invention to provide a fire extinguishing system in which a relief mechanism from a secondary side pipe to a primary side pipe is installed so that the pump can be started without delay in the event of a fire. There is.

In order to achieve the above object, the present invention provides the following fire extinguishing equipment.
That is, to the pump that sends the water from the water source to the pipe, the water flow detection device connected to the pump by the pipe, the sprinkler head connected to the secondary side pipe of the water flow detection device, and the primary side pipe of the water flow detection device. Equipped with an installed pump start switch, multiple water flow detection devices are installed in each protection area, and the primary side piping leads to the pump, and on the bypass piping that bypasses the primary side and secondary side of the water flow detection device. The relief valve installed in is opened when the pressure difference on the secondary side with respect to the pressure on the primary side is equal to or greater than the specified value, and the pressure of water in the secondary side piping at all times and the primary when the pump start switch is activated. This is a fire extinguishing facility in which the pressure difference when the relief valve is opened is larger than the difference with the pressure of the water in the side pipe.

According to the above, a fire is caused by increasing the pressure difference when the relief valve is opened with respect to the difference between the pressure of water in the secondary piping at all times and the operation set pressure of the pump start switch. At times the pump can be started before the relief valve opens. More specifically, if the pressure of water in the secondary side piping is 1 MPa and the operation set pressure of the pump start switch is 0.7 MPa, the difference is 0.3 MPa. Further, the pressure difference on the secondary side with respect to the pressure on the primary side when the relief valve is opened shall be within the range of 0.3 to 0.4 MPa. When the pressure of the primary side pipe reaches 0.7 MPa in the event of a fire, the pump start switch is activated and the pump operates to start water supply to the secondary side pipe. At this time, the pressure difference between the primary side and the secondary side of the relief valve is about 0.3 MPa, and the pump starts before or immediately after opening the relief valve.

Further, the present invention includes a pump that sends water from a water source to a pipe, a water flow detection device connected to the pump by a pipe, a sprinkler head connected to a secondary side pipe of the water flow detection device, and a primary water flow detection device. It is equipped with a pump start switch installed in the side pipe and an auxiliary pressurizing pump that starts when the pressure in the primary side pipe is higher than the operation set pressure of the pump start switch, and the water flow detection device is provided for each protection area. Multiple installed primary side pipes lead to the pump, and the relief valve installed on the bypass pipe that bypasses the primary side and secondary side of the water flow detection device is the pressure difference on the secondary side with respect to the pressure on the primary side. When the relief valve opens more than the difference between the pressure of water in the secondary side pipe and the pressure of water in the primary side pipe when the auxiliary pressurizing pump operates. It is a fire extinguishing facility with a larger pressure difference.

The auxiliary pressurizing pump is installed on the primary side piping, and its discharge rate is smaller than that of the pump. In the fire extinguishing equipment with the above configuration, for example, when the pressure of water in the secondary side piping is 1 MPa and the operating pressure of the auxiliary pressurizing pump is in the range of 0.7 to 0.8 MPa, the difference is 0.2 to 0.8. It becomes 0.3 MPa. On the other hand, the pressure difference on the secondary side with respect to the pressure on the primary side when the relief valve is opened shall be within the range of 0.3 to 0.4 MPa. If a leak occurs from the primary side piping during a non-fire situation and the water in the piping is gradually depressurized, the auxiliary pressurizing pump will start before the pump start switch operates to supply water to the primary side. Is performed, so the relief valve does not open.

As described above, according to the present invention, in a fire extinguishing system in which a relief mechanism from the secondary side pipe to the primary side pipe is installed, before the relief valve is opened by decompression in the primary side pipe in the event of a fire. Since the pump is started and water is sent to the secondary side piping, it is possible to realize a fire extinguishing system in which the pump is started without delay in the event of a fire.

Further, when a leak occurs in the primary side pipe and the pressure is reduced in a non-fire state, the relief valve does not open, and there is an advantage that the pressure in the pipe can be appropriately maintained.

The piping system diagram of the sprinkler system to which this invention was applied. Front view of the flow detection device. Top view of the flow detection device. Front view with the cover of the water flow detection device removed. Sectional view of relief valve. The piping system diagram of the foam fire extinguishing equipment to which this invention was applied.

Hereinafter, the present invention will be described with reference to the drawings. The fire extinguishing equipment shown in FIG. 1 is a sprinkler equipment, and includes a water source W, a pump P, a primary side pipe 1, a secondary side pipe 2, a water flow detection device 3, and a sprinkler head S.

The water source W is a water tank in which water used for extinguishing a fire is stored, and is generally installed in the basement of a building. A pump P is installed in the vicinity of the water source W, and the water of the water source W can be sent to the primary side pipe 1 by the pump P.

A water flow detection device 3 is installed in the primary side pipe 1. The flow water detection device 3 is installed in each protected area, so that the primary side pipe 1 is branched in the middle, and the flow water detection devices 3a, 3b, and 3c are installed on the branch pipes, respectively.

A pressure tank T is installed between the water flow detection device 3 and the pump P, and a pump start switch 5 is installed in the pressure tank T. The pump start switch 5 operates when the pressure of the primary side pipe 1 becomes equal to or lower than a predetermined pressure to start the pump P. In this embodiment, the set pressure of the pump start switch 5 is 0.7 MPa.

The water flow detection device 3 shown in FIGS. 2 to 4 includes a valve body 32 having a swing check structure inside a tubular main body 31. The valve body 32 has a disk shape and is normally closed, and only allows water to flow from the primary side pipe 1 to the secondary side pipe 2. The flow water detection device 3 is an actuated valve type flow water detection device that detects the displacement due to the opening of the valve body 32 and outputs a signal. Specifically, the stem 32a connected to the flow water detection mechanism 31b installed outside the main body 31 is displaced with the opening operation of the valve body 32, and the displacement is provided in the flow water detection mechanism 31b (illustration). Detects with) and outputs a signal. As an example of the water flow detection device having such a structure, there are those described in JP-A-2010-5429 and JP-A-2016-135451. Here, a detailed description of the structure of the water flow detection device 3 will be omitted.

The flow water detection device 3 is provided with an opening covered by a cover 31a on the front side. A flow water detection mechanism 31b is arranged on one side surface of the flow water detection device 3, and a drain valve 31c is arranged on the other side surface.

Piping 34 and 35 are installed on the front side of the main body 31. The pipe 34 is connected to the hole 34a installed on the primary side pipe 1 side of the valve body 32 in the main body 31, and the pipe 35 is a hole installed on the secondary side pipe 2 side of the valve body 32 in the main body 31. It is connected to 35a. The tips of the pipes 34 and 35 are connected to the three-way joint 36, and a pressure gauge 33 is installed at the upper connection port of the three-way joint 36 in the drawing. Further, the connection port on the left side of the three-way joint 36 is connected to the pipe 37 bent in a U-shape. The bypass pipe is from the pipe 34 to the pipe 35 via the pipe 37.

The bypass pipe may be installed in the main body 31 of the water flow detection device 3 as described above, or may be configured by directly connecting the pipe 34 and the primary side pipe 1 and the pipe 35 and the secondary side pipe 2.

A relief valve 4 is installed between one end side of the pipe 37 and one of the three-way joints 36. The relief valve 4 can pass water from the secondary side pipe 2 to the primary side pipe 1, and the valve body 41 installed inside the tubular main body 40 is urged to the valve seat 43 by the spring 42. , The valve body 41 is always closed.

In the main body 40 of the relief valve 4, the end on the side where the valve seat 43 is installed continues to the pipe 35 (secondary side pipe 2), and the end on the side where the tubular holder 44 is installed is the pipe 34 (the end on the side where the tubular holder 44 is installed). It continues to the primary side piping 1). The main body 40 is arranged at a position intersecting the flow direction of the water flow detection device 3 (from bottom to top in FIGS. 2 and 4). With such a configuration, the main body 40 can be installed horizontally in the drawing. In particular, since the actuated valve type water flow detection device 3 generally has a narrow inter-plane dimension, the relief valve 4 can be installed on the bypass pipe installed in the main body 31 by the above configuration.

The spring 42 is installed between the valve body 41 and the holder 44. The spring 42 applies to the valve body 41 when the pressure of the pipe 35 (secondary side pipe 2) exceeds the pressure of the pipe 34 (primary side pipe 1) by about 0.3 to 0.4 MPa. The valve body 41 is opened by contracting.

The force that the spring 42 acts on the valve body 41 can be adjusted by the position of the holder 44. As described above, the valve body 41 opens when the pressure difference between the pressure of the primary side pipe 1 and the pressure of the secondary side pipe 2 exceeds a predetermined value. As a case where differential pressure occurs, when the valve body 41 is closed, the fluid pressure on the inflow side (secondary side pipe 2) rises and a difference from the fluid pressure on the outflow side (primary side pipe 1) occurs. There are two states, one is the state where the fluid pressure is on the outflow side (primary side pipe 1) and the other is a state where the fluid pressure on the inflow side (secondary side pipe 2) is different from the fluid pressure on the inflow side (secondary side pipe 2). In either case, the valve body 41 is not opened by a slight differential pressure, and the valve body 41 is pressed and held by the spring 42 against the valve seat 43 so that the valve body 41 opens after a certain amount of differential pressure is generated. are doing.

Specifically, when the maximum working pressure of the flow water detection device 3 is 1.4 MPa and the pressure of the water filled inside the secondary side pipe 2 is 1 MPa, before the maximum working pressure of the flow water detection device 3 is exceeded. The valve body 41 is set to open before the differential pressure reaches 0.4 MPa so that the valve body 41 opens at the stage of. Preferably, the differential pressure is set in the range of 0.15 MPa to 0.4 MPa. In the present embodiment, the valve body 41 is set to open within the range of the differential pressure of 0.3 MPa to 0.4 MPa.

The valve seat 43 has a cylindrical shape, and fluororesin is used as the material. The material of the O-ring 45 installed on the valve body 41 in contact with the valve seat 43 is fluororubber. This prevents the valve body 41 and the valve seat 43, which have been closed for a long period of time, from sticking to each other. As the material of the valve seat 43, in addition to the fluororesin, it is also possible to use a metal valve seat 43 coated with the fluororesin on the surface. Alternatively, the fluororesin coating may be applied only to the surface that comes into contact with the valve body 41.

The inside of the valve seat 43 is a hole. In the relief valve 4, the cross-sectional area of the hole inside the valve material 43 is the "cross-sectional area of the minimum flow diameter portion", which is a fluid on a virtual plane perpendicular to the central axis of the main body 40 of the relief valve 4. Is the part where the cross-sectional area of the part through which is possible is the minimum.

The holder 44 has a male screw screwed with a female screw installed on the inner peripheral surface of the main body 40 on the outer peripheral surface. As a result, the position of the holder 44 can be changed, and the force with which the spring 42 presses the valve body 41 can be adjusted. The holder 44 is provided with a center hole 46 and a plurality of distribution holes 47 formed around the center hole 46. In this embodiment, four distribution holes 47 are installed.

A valve rod 41a extending from the valve body 41 toward the holder 44 is inserted into the center hole 46. The center hole 64 has a function of guiding the valve rod 41a when the valve body 41 opens and closes. When the valve body 41 is opened, the water filled in the inside of the secondary side pipe 2 passes through the flow hole 47 and flows to the primary side pipe 1.

The sprinkler head S is installed in the secondary side pipe 2 and automatically operates by detecting the heat of the fire. The structure of the sprinkler head S is known, and detailed description of the internal structure is omitted here. The sprinkler head S has a nozzle connected to the secondary side pipe 2 inside, and the diameter of the outlet side of the nozzle is set so that the amount of water discharged is 80 L / min. The nozzle outlet is always closed by a valve, which is supported by a thermal decomposition section. The heat-sensitive decomposition unit is decomposed and operated by the heat of a fire, and examples of the heat-sensitive decomposition unit are described in JP-A-7-284545 and JP-A-2015-37678.

Here, the cross-sectional area of the minimum flow diameter portion of the relief valve 4 is smaller than the cross-sectional area of the nozzle outlet of the sprinkler head S, and the cross-sectional area of the nozzle outlet of the sprinkler head S and the cross-sectional area of the minimum flow diameter portion of the relief valve 4. The ratio of is 1: 0.3 or less. If the value of this ratio becomes too small, dust tends to be clogged inside the relief valve 4, so it is more preferably set in the range of 0.2 to 0.03.

Further, in the above relief valve 4, the hole inside the valve seat 43 has the cross-sectional area of the minimum distribution diameter portion, but the total cross-sectional area of all the distribution holes 47 (4 points) of the holder 44 is larger than this. If is smaller, the total cross-sectional area of the flow hole 47 is the cross-sectional area of the minimum flow diameter portion.

Next, the operation at the time of a fire in the fire extinguishing equipment having the above configuration will be described.

In the fire extinguishing equipment shown in FIG. 1, the pressure of the secondary side pipe 2 is set higher than the pressure of the primary side pipe 1 in normal times (during non-fire). For example, when the pressure of the secondary side pipe 2 is 1 MPa, the pressure of the primary side pipe 1 is 0.9 MPa, which is lower than that. The operating pressure of the pump start switch 5 is 0.7 MPa as described above.

When a fire breaks out in the protected area of the flow water detection device 3a, the sprinkler head S connected to the secondary side pipe 2a of the flow water detection device 3a operates. The nozzle 61 of the operated sprinkler head S is opened, and the water filled in the secondary side pipe 2a is sprayed into the room, so that the pressure in the secondary side pipe 2a decreases.

The decompression of the secondary side pipe 2a opens the valve body 32 of the water flow detection device 3a, and water is supplied from the primary side pipe 1 to the secondary side pipe 2. Further, the water flow detection device 3a outputs an operation signal by the opening operation of the valve body 32. When the pressure of the primary side pipe 1 gradually decreases and becomes lower than 0.7 MPa, the relief valves 4b and 4c of the non-fire section open the valve body 41, but when the pressure of the primary side pipe reaches 0.7 MPa, the pump The start switch 5 is activated and the pump P is started. Water from the water source W is continuously sent from the pump P, and a sufficient amount of water is sprayed from the activated sprinkler head S to suppress the fire.

In the above, when the relief valve 4 (4b, 4c) is opened before the pump P is started, the amount of flowing water supplied from the secondary side pipes 2b and 2c to the primary side pipe 1 is discharged from the operated sprinkler head S. Since the amount of flowing water is smaller than the amount of flowing water, the pressure of the primary side pipe 1 is further reduced, and the pump start switch 5 is operated, so that the start of the pump P is not delayed.

Subsequently, the configuration of the fire extinguishing equipment of the present invention other than that described above will be described.

In the primary side pipe 1, an auxiliary pressurizing pump 7 is installed between the pump P and the water flow detection device 3. The auxiliary pressurizing pump 7 has a smaller discharge amount than the pump P described above, and requires less power for operation. For example, in winter, when the pressure of the secondary side pipe 2 decreases and the valve body 32 of the water flow detection device 3 opens slightly and the primary side pipe 1 is filled with water to the secondary side pipe 2, the primary side in a non-fire situation. The auxiliary pressurizing pump 7 is used when the pressure in the pipe 1 is reduced. When the pressure of the primary side pipe 1 at the time of starting the pump P is set to 0.7 MPa and the pressure of the primary side pipe 1 at which the auxiliary pressurizing pump 7 is started is set to 0.8 MPa, before the pump P is started. The auxiliary pressurizing pump 7 is activated to send water to recover the reduced pressure in the pipe. The amount of flowing water when the relief valve 4 is opened is smaller than the amount of discharge of the auxiliary pressurizing pump 7.

Regarding the auxiliary pressurizing pump 7, the pressure difference when the relief valve is opened is larger than the difference between the pressure of water in the secondary side piping at all times and the pressure of water in the primary side piping when the auxiliary pressurizing pump is operated. Is set to be larger. More specifically, when the pressure of the water in the secondary side pipe 2 is 1 MPa and the starting pressure of the auxiliary pressurizing pump 7 is 0.8 MPa, the differential pressure is 0.2 MPa, which is the relief valve described above. It is smaller than the differential pressure (0.3 to 0.4 MPa) when 4 is opened. Therefore, when the water in the primary side pipe 1 leaks and the pressure is reduced during a non-fire, the auxiliary pressurizing pump 7 is activated and water is supplied from the water source W to the primary side pipe 1. The auxiliary pressurizing pump 7 stops operation when the primary side pipe 1 reaches a predetermined pressure. In this way, the relief valve 4 does not open even if a leak occurs from the primary side pipe 1 during a non-fire situation.

Further, in the primary side pipe 1, a safety valve 8 is installed between the pump P and the water flow detection device 3. The safety valve 8 has a function of letting the water of the primary side pipe 1 escape to the outside when the pressure of the primary side pipe 1 becomes too high and exceeds a predetermined pressure. The pressure at which the safety valve 8 opens is set to a value higher than the pressure at which the auxiliary pressurizing pump 7 operates.

On the other hand, some buildings such as large warehouses and factories have a folded plate roof structure. The folded plate roof has the advantages that the folded plate made of metal is lightweight and inexpensive, and the construction period is short. However, after the building is completed, the outside temperature such as the heat of summer and the cold of winter Is susceptible to heat transfer from. For this reason, the water inside the secondary side pipe 2 arranged near the attic of the folded plate roof is abnormally pressurized in the summer, and is easily frozen in the winter, and the sprinkler head S is easily damaged. According to the present invention, it is possible to prevent the sprinkler head S from being damaged due to abnormal pressure increase or freezing of water in the secondary side pipe 2 arranged near the folded plate roof, and the pump P can be started without delay in the event of a fire. It is done and the fire can be extinguished quickly.

In the embodiment described above, the sprinkler system has been described as an example, but the present invention can also be applied to a foam fire extinguishing system or the like in which a chemical is contained in fire extinguishing water. As shown in FIG. 6, the foam fire extinguishing equipment has a chemical tank 9a and a mixer 9b, and when the sprinkler head S is activated and the pump P is started in the event of a fire, the chemical (foam stock solution) in the chemical tank 9a is mixed. The foam aqueous solution sent to 9b and mixed with the water of the water source W at a predetermined ratio is sent to the water flow detection device 3. The foam aqueous solution that has passed through the simultaneous release valve 9c via the flow water detection device 3 is sprayed from the foam head 9d.

In particular, since the foam fire extinguishing equipment is installed in the parking lot, all or part of the secondary side piping 2 may be installed outdoors. According to the present invention, the sprinkler head S (sensing head) and the simultaneous release valve 9c installed on the secondary side (secondary side pipe 2) of the water flow detection device in the foam fire extinguishing equipment abnormally boost the water inside the secondary side pipe. It can be prevented from being damaged by freezing. Further, in the event of a fire, the pump P can be started without delay and the fire can be extinguished quickly. The relief valve 4 described above shall be installed in the sensing line piping connected to the simultaneous release valve 9c and the sprinkler head S installed, and in the piping (not shown) that bypasses the primary side piping of the simultaneous release valve 9c. Is also possible.

A control device C is installed in the fire extinguishing equipment shown in FIGS. 1 and 6, and a water flow detection device 3, a pump start switch 5, a pump P, and an auxiliary pressurizing pump 7 are electrically connected to each other. Although the control device C is described in only one place in the figure, it is also possible to separately install the control device C in the vicinity of the constituent devices such as the pump P and the auxiliary pressurizing pump 7. By setting the control device C, it is possible to start the pump P immediately after the operation signal of the water flow detection device 3 is output.

The above fire extinguishing equipment is equipped with a pump that sends water from the water source to the pipe, a water flow detection device connected to the pump by the pipe, and a sprinkler head connected to the secondary side pipe of the water flow detection device. Multiple water flow detection devices are installed in each protected area, and the primary side piping leads to the pump. The pump is activated by the operation signal of the water flow detection device, and is on the bypass pipe that bypasses the primary and secondary sides of the water flow detection device. The relief valve installed in is opened when the pressure difference on the secondary side is greater than or equal to the specified pressure on the primary side, and the cross-sectional area of the minimum flow diameter of the relief valve is larger than the cross-sectional area of the nozzle outlet of the sprinkler head. It is composed small.

1 Primary side piping
2 (2a, 2b, 2c) Secondary side piping
3 (3a, 3b, 3c) Flow detection device
4 (4a, 4b, 4c) relief valve
5 Pump start switch
7 Auxiliary pressurizing pump
8 Safety valve
9a drug tank
9b mixer
9c Simultaneous release valve
9d foam head
31 Main body of water flow detection device
32 Valve body of water flow detection device
33 pressure gauge
34, 35, 37 plumbing
36 Three-way fitting
40 Relief valve body
41 Relief valve valve body
42 spring
43 Valve seat
44 holder
P pump
S sprinkler head
T pressure tank
W water source

Claims (11)

A pump that sends water from the water source to the pipe,
A water flow detector connected by a pump and piping,
The sprinkler head connected to the secondary piping of the water flow detector,
It is equipped with a pump start switch installed on the primary side piping of the water flow detection device.
Multiple water flow detection devices are installed in each protected area, and the primary side piping leads to the pump.
The relief valve installed on the bypass pipe that bypasses the primary and secondary sides of the water flow detection device opens when the pressure difference on the secondary side is greater than or equal to the specified pressure on the primary side, and is always on the secondary side. A fire extinguishing facility characterized in that the pressure difference when the relief valve is opened is larger than the difference between the pressure of water in the pipe and the pressure of water in the primary side pipe when the pump start switch is operated. A pump that sends water from the water source to the pipe,
A water flow detector connected by a pump and piping,
The sprinkler head connected to the secondary piping of the water flow detector,
A pump start switch installed on the primary side piping of the water flow detection device,
It is equipped with an auxiliary pressurizing pump that starts when the pressure in the primary side piping is higher than the operation set pressure of the pump start switch.
Multiple water flow detection devices are installed in each protected area, and the primary side piping leads to the pump.
The relief valve installed on the bypass pipe that bypasses the primary and secondary sides of the water flow detection device opens when the pressure difference on the secondary side is greater than or equal to the specified pressure on the primary side, and is always on the secondary side. A fire extinguishing facility characterized in that the pressure difference when the relief valve is opened is larger than the difference between the pressure of water in the pipe and the pressure of water in the primary side pipe when the auxiliary pressurizing pump is operated. The fire extinguishing system according to claim 1 or 2, wherein the relief valve is opened before the difference in pressure in the secondary pipe with respect to the pressure in the primary pipe reaches 0.4 MPa. The fire extinguishing system according to any one of claims 1 to 3, wherein the relief valve is installed on a bypass pipe installed in the main body of the water flow detection device. The fire extinguishing system according to any one of claims 1 to 4, wherein the relief valve is arranged at a position intersecting the flow direction of the water flow detection device. 6. Fire extinguishing equipment. The fire extinguishing system according to any one of claims 1 to 6, wherein the pressure inside the secondary pipe is set higher than the pressure inside the primary pipe in normal times. The fire extinguishing according to any one of claims 1 to 3, wherein a safety valve is installed on the primary side pipe to discharge the water inside the primary side pipe to the outside when the primary side pipe exceeds a predetermined pressure. Facility. 6. Fire extinguishing equipment. The fire extinguishing system according to any one of claims 1 to 9, wherein the secondary side piping is installed near the folded plate roof. The fire extinguishing system according to any one of claims 1 to 10, which is installed in a place where all or part of the secondary side piping is exposed to the outside air.

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