Fixed foam fire extinguishing equipment

Abstract

To obtain a fixed foam fire extinguishing system for self-service gas stations that has fire extinguishing performance comparable to that of systems using aqueous film-forming foam fire extinguishing agents. [Solution] A fixed foam fire extinguishing system characterized by having a nozzle that discharges a foam fire extinguishing agent that does not contain organic fluorine compounds in a mist or foam form.

Description

[Technical Field]

[0001] The present invention relates to fixed foam fire extinguishing equipment using a foam fire extinguishing agent, and particularly relates to a foam fire extinguishing agent for self-service gas stations and fixed foam fire extinguishing equipment using the same. [Background Art]

[0002] In Japan, a foam fire extinguishing agent is defined as an agent obtained by adding a foam stabilizer and other agents to a base material, which is mixed with water (including seawater) to a predetermined concentration, and mechanically mixed with air or inert gas to generate foam for fire extinguishing use. By being foamed into foam, the foam fire extinguishing agent covers the surface of a fire and extinguishes the fire through cooling and suffocation effects. There are three types of such foam fire extinguishing agents: synthetic surfactant foam fire extinguishing agents, aqueous film-forming foam fire extinguishing agents, and protein foam fire extinguishing agents.

[0003] Meanwhile, as a fire that occurs at a self-service gas station, a leakage fire caused by leakage and outflow of vehicle fuel such as gasoline (flammable liquid) due to some cause is assumed as the most severe scenario. Therefore, foam fire extinguishing agents used for self-service gas stations are required to have fire extinguishing capability against such leakage fires of flammable liquids.

[0004] Conventionally, aqueous film-forming foam fire extinguishing agents have been used in foam fire extinguishing equipment for self-service gas stations. Specifically, although protein foam fire extinguishing agents generally have excellent heat resistance, when supplied in a foamed state on the fuel surface, the spreading speed of the agent is slow, making them unsuitable for outflow fires. Further, synthetic surfactant foam fire extinguishing agents have excellent foaming capability but low heat resistance, and the agent foamed and spread on the fuel surface is easily defoamed by the heat of gasoline fire, resulting in long fire extinguishing time. Therefore, aqueous film-forming foam fire extinguishing agents, which have a good balance of fast foaming and spreading on the fuel surface and heat resistance against fire, have been suitable for parking lot applications.

[0005] The most significant factor in enabling aqueous film-forming foam fire extinguishing agents to possess the above-mentioned performance is the inclusion of fluorinated surfactants (for example, Patent Document 1). However, the organofluorine compounds contained in fluorinated surfactants are not easily decomposed in nature and tend to remain and accumulate in the environment and ecosystems for a long time. Concerns about such environmental impacts have led to a global movement to regulate the use of organofluorine compounds.

[0006] In Japan, the manufacture and sale of new products containing PFOS and PFOA are already regulated. In the near future, it is predicted that substances that can become PFOA through chemical changes, known as PFOA-related substances, as well as PFHxS (a six-carbon version of PFOS), PFHxA (a six-carbon version of PFOA), and related substances will also be subject to regulation, and eventually, all perfluorinated compounds (PFAS) will be regulated.

[0007] To lower surface tension and meet various performance requirements as a fire extinguishing agent, aqueous foam fire extinguishing agents use surfactants containing fluorine compounds as one of their components. In the industry, it is even considered virtually impossible to meet the various performance requirements of aqueous foam fire extinguishing agents with surfactants that do not contain fluorine compounds. In other words, the prevailing view is that fluorine-based surfactants are an essential component of aqueous foam fire extinguishing agents.

[0008] However, if fluorinated surfactants containing organofluorine compounds become unusable, it will no longer be possible to manufacture aqueous film-forming foam fire extinguishing agents. This means that there will be no foam fire extinguishing agent suitable for use in self-service gas stations. Therefore, there is an urgent need to develop alternative products that have fire extinguishing performance as foam fire extinguishing agents for self-service gas stations without using fluorinated surfactants. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Japanese Patent Publication No. 2007-252731 [Overview of the project] [Problems that the invention aims to solve]

[0010] The inventors focused on synthetic interfacial foam fire extinguishing agents that do not contain fluorine-based surfactants, and using these as the base formulation, they made various improvements to the foam's fire resistance, heat resistance, oil resistance, etc., and adjusted the nozzle, successfully developing a fixed foam fire extinguishing system for self-service gas stations that achieves fire extinguishing performance comparable to that of systems using aqueous film-forming foam fire extinguishing agents. [Means for solving the problem]

[0011] In other words, the present invention provides a fixed foam fire extinguishing system characterized by comprising a nozzle for discharging a foam fire extinguishing agent that does not contain organofluorine compounds.

[0012] In the fixed foam fire extinguishing system of the present invention described above, it is preferable that the foam fire extinguishing agent includes at least one selected from the group consisting of myristyl alcohol and lauryl alcohol.

[0013] Furthermore, the foam fire extinguishing agent used in the fixed foam fire extinguishing system of the present invention may be any of the following: (1) containing myristyl alcohol in an amount greater than 0.0% by mass and 1.0% by mass or less; (2) containing lauryl alcohol in an amount greater than 0.0% by mass and 1.7% by mass or less; or (3) containing myristyl alcohol in an amount of 0.4% by mass or more and 0.6% by mass or less and lauryl alcohol in an amount of 0.2% by mass or more and 0.5% by mass or less.

[0014] Furthermore, in the fixed foam fire extinguishing system of the present invention described above, the foaming ratio of the nozzle is preferably 3 to 8 times, and more preferably 4 to 6 times. [Effects of the Invention]

[0015] According to the present invention, it is possible to realize a fixed foam fire extinguishing system for self-service gas stations that has fire extinguishing performance comparable to that of systems using aqueous film-forming foam fire extinguishing agents. [Brief explanation of the drawing]

[0016] [Figure 1] It is a schematic diagram of the foam fire extinguishing equipment used in experiments on foam fire extinguishing agents. [Figure 2] It is a diagram showing a nozzle used in experiments on foam fire extinguishing agents. [Figure 3] It is a diagram showing another nozzle used in experiments on foam fire extinguishing agents. MODE FOR CARRYING OUT THE INVENTION

[0017] Hereinafter, representative embodiments of the fixed foam fire extinguishing equipment according to the present invention will be described in detail with reference to the drawings. Although the present invention is not limited to these drawings, since the drawings are for conceptually explaining the present invention, dimensions, ratios or numbers may be exaggerated or simplified as necessary for ease of understanding. Note that the self-service gas station in the present invention may also be referred to as a self-service gasoline station, a self-service station or the like.

[0018] The foam fire extinguishing agent in the present embodiment is based on a synthetic surfactant foam fire extinguishing agent. That is, the foam fire extinguishing agent contains a synthetic surfactant (for example, a hydrocarbon-based surfactant) as a main component, with foam stabilizers such as glycol ethers and higher alcohols, antifreeze agents such as glycols, and rust inhibitors added thereto, but does not contain any organic fluorine compounds.

[0019] The foam fire extinguishing agent further contains at least one higher alcohol selected from the group consisting of any of the following higher alcohols: myristyl alcohol and lauryl alcohol. More specifically, the higher alcohol is included in the blending ratios described in (1) to (3) below. (1) More than 0.0 mass% and not more than 1.0 mass% of myristyl alcohol (2) More than 0.0 mass% and not more than 1.7 mass% of lauryl alcohol (3) 0.4 mass% to 0.6 mass% of myristyl alcohol, and 0.2 mass% to 0.5 mass% of lauryl alcohol

[0020] The Applicant has confirmed through this formulation that the foam fire extinguishing agent according to the present embodiment has performance equal to or higher than that of aqueous film-forming foam fire extinguishing agents in fire extinguishing performance tests for self-service gas stations. In particular, a foam fire extinguishing agent having a blending ratio of 1.0% by mass of lauryl alcohol (0% by mass of myristyl alcohol) is preferable from the viewpoint of high fire extinguishing performance.

[0021] That is, it is generally accepted that synthetic surfactant foam fire extinguishing agents are poor in foam fire resistance, heat resistance and oil resistance, but the above formulation modification improves the foam's fire resistance, heat resistance and oil resistance, making it possible to obtain fire extinguishing performance equivalent to that of aqueous film-forming foam fire extinguishing agents. When the content exceeds each of the above upper limits, the long-term stability of the fire extinguishing agent is impaired, precipitation occurs during long-term storage, and turbidity occurs when the fire extinguishing agent is diluted with water.

[0022] It should be noted that the above formulation modification (adding higher alcohol and adjusting other components) to obtain fire extinguishing performance for self-service gas stations equivalent to that of aqueous film-forming foam fire extinguishing agents results in the loss of performance in seawater dilution and high-foaming performance that are characteristic of synthetic surfactant foam fire extinguishing agents. However, for use in self-service gas stations, dilution of the fire extinguishing agent with seawater and the use of high-foaming equipment are not assumed, so there is no adverse effect in practical use.

[0023] The above-described foam fire extinguishing agent can be suitably used in foam fire extinguishing equipment, particularly fixed foam fire extinguishing equipment. Foam fire extinguishing equipment sprays an aqueous solution obtained by proportionally mixing water and a fire extinguishing agent from a foam discharge outlet as air-containing foam or in the form of mist (that is, in the form of water droplets or fine particles), covering the combustion surface to block air and extinguishing the fire through a cooling effect. Foam fire extinguishing equipment targets flammable liquids. In the present embodiment, it is particularly suitably installed in areas used for self-service gas stations.

[0024] The foam fire extinguishing agent may, as other components, include optional components conventionally used in foam fire extinguishing agents. Examples include solvents, rust inhibitors, active agents, pH adjusters, pH stabilizers and the like.

[0025] The self-service stationary fixed foam fire extinguishing system of this embodiment can consist of a storage box, a foam fire extinguishing agent storage container, an antifreeze storage container, a mixer, a pressurizing gas container, a release device, a pressure regulator, a discharge compartment selection valve, a pressure switch, a safety valve, a foam discharge port including a nozzle, piping and valves, and an emergency power supply, etc. (see, for example, Figure 1).

[0026] In this embodiment of the fixed foam fire extinguishing system, the foam fire extinguishing agent is initially in a mist form when discharged from the nozzle, and then foams up when it strikes the target object to be extinguished, such as an oily surface. While conventionally known nozzles can be used to discharge the foam fire extinguishing agent in this manner, the inventors have diligently investigated and found a preferred nozzle shape in the experimental examples described later. Furthermore, the inventors have confirmed that in this embodiment of the fixed foam fire extinguishing system, the foaming ratio of the nozzle is preferably 3 to 8 times, and even more preferably 4 to 6 times.

[0027] Furthermore, in fixed foam fire extinguishing systems for self-service fire stations, the foam discharge outlet (foam head), including the nozzle, may be positioned on the island or other structure itself, such as a concrete exposed island or a steel formwork island, or on top of or around them. For example, on an island, multiple foam heads may be positioned at predetermined intervals along a substantially vertical side.

[0028] The present invention will be described in more detail below using various experimental examples, but the present invention is not limited to these. [Examples]

[0029] (1) Preparation of foam fire extinguishing agent First, for the experimental example, we prepared a foam fire extinguishing agent with the formulation shown in Table 1. [Table 1]

[0030] (2) Fire extinguishing test The prepared foam fire extinguishing agent was diluted to 3%, and its fire extinguishing performance was evaluated according to the following test methods and standards specified in "Section 10 Fire Extinguishing Performance" of the "Test of Package-Type Fixed Foam Fire Extinguishing Equipment Installed at Self-Service Fueling Stations" (Fire Safety Notification No. 119, August 27, 2019).

[0031] (A) Fire extinguishing test (horizontal discharge method) A. Prepare the test apparatus shown in Figure 1. (i) Pour 20 liters of gasoline into the fuel oil container and confirm that there are no leaks. (c) Use an ignition rod or similar device to ensure safety before igniting. E. Start extinguishing the fire 20 seconds after ignition. In this case, the activation device shall be operated considering the timing of foam discharge from the fixed foam fire extinguishing system used in the test. (o) Measure the time until the fire is extinguished. The fire is considered extinguished when the flame in the fuel oil container is extinguished.

[0032] (B) Judgment criteria A. Extinguish the fire within one minute of foam discharge beginning. (i) No re-ignition after foam discharge has stopped.

[0033] (C) Other conditions (C-1) Nozzle Six types of nozzles were prepared for use in the foam outlet of the test apparatus shown in Figure 1. First, nozzle 1-1 (radiation port angle α = 45°) shown in Figure 2 was prepared. Figure 2 shows the front view, side view, and cross-sectional view along line AA of the nozzle used in the experimental example. The radiation port has a roughly fan-shaped cross-section. Nozzles 1-2, 1-3, and 1-4 were also prepared, with the radiation port angle α shown in Figure 2 adjusted to 70°, 60°, or 50°.

[0034] In addition, nozzle 2, as shown in Figure 3, was also prepared. In the cross-sectional view of line DD in Figure 3(B), the nozzle with an open air vent in the area indicated by the symbol P was designated as nozzle 2-2, while the nozzle with the air vent closed was designated as nozzle 2-1.

[0035] (C-2) Conditions Furthermore, during the above fire extinguishing test, the ambient temperature was 21.5-23.5°C, the humidity was 99%, and the temperature of the diluted foam fire extinguishing agent was 21.0-21.5°C.

[0036] (3) Results Table 2 shows the nozzles 1-6 used and the results of the fire extinguishing tests. The six types of nozzles in Table 2 can be summarized as follows: • Nozzle 1-1: Radiation angle α = 45° • Nozzle 1-2: Radiation angle α = 70° • Nozzle 1-3: Radiation angle α = 60° • Nozzle 1-4: Radiation angle α = 50° • Nozzle 2-1 without air vent • Nozzle 2-2 with air vents

[0037] [Table 2]

[0038] In Experimental Examples 1-7, the foam fire extinguishing agent was discharged in a mist-like state and then as foam. From the results shown in Table 2, it was found that a discharge pressure of 0.10-0.15 MPa is preferable, and a foaming ratio of 3-8 times is preferable.

[0039] The above describes one embodiment of a fixed foam fire extinguishing system using a foam fire extinguishing agent, which is one embodiment of the present invention. However, the present invention is not limited to these embodiments, and various design modifications are possible as long as they embody the technical concept of the present invention, and all such design modifications fall within the technical scope of the present invention.

Claims

1. It shall be equipped with a nozzle that discharges a foam fire extinguishing agent that does not contain perfluorinated compounds. A fixed-type foam fire extinguishing system characterized by the following:

2. The aforementioned foam fire extinguishing agent contains at least one selected from the group consisting of myristyl alcohol and lauryl alcohol. A fixed foam fire extinguishing system according to claim 1, characterized by the following:

3. It contains more than 0.0% by mass and 1.0% by mass or less of myristyl alcohol. A fixed foam fire extinguishing system according to claim 2, characterized by the above.

4. It contains more than 0.0% by mass and 1.7% by mass or less of lauryl alcohol. A fixed foam fire extinguishing system according to claim 2, characterized by the above.

5. It contains 0.4% to 0.6% by mass of myristyl alcohol and 0.2% to 0.5% by mass of lauryl alcohol. A fixed foam fire extinguishing system according to claim 2, characterized by the above.

6. The foaming ratio of the nozzle is 3 to 8 times. A fixed foam fire extinguishing system according to claim 1, characterized by the following:

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