Fire extinguishing foam and fixed fire extinguishing foam system using same

Abstract

The present invention obtains a synthetic surfactant–based fire extinguishing foam comparable to an aqueous film–forming fire extinguishing foam in terms of the fire extinguishing performance when used in a parking lot, and a fixed fire extinguishing foam system using the fire extinguishing foam. The present invention provides: a fire extinguishing foam characterized by containing at least one alcohol selected from the group consisting of myristyl alcohol and lauryl alcohol; and a fixed fire extinguishing foam system using the fire extinguishing foam.

Description

Foam fire extinguishing agent and fixed foam fire extinguishing equipment using the same

[0001] The present invention relates to a foam fire-extinguishing agent and a fixed foam fire-extinguishing system using the same, and more particularly to a foam fire-extinguishing agent for use in parking lots and a fixed foam fire-extinguishing system using the same.

[0002] In Japan, foam fire extinguishing agents are defined as agents that are made by adding foam stabilizers and other agents to a base material, mixed with water (including seawater) to a certain concentration, and then mechanically mixed with air or an inert gas to generate foam, which is used to extinguish fires. Foam fire extinguishing agents are foamed to form foam, which covers the surface of the fire and extinguishes the fire through a cooling and suffocating effect. There are three types of foam fire extinguishing agents: synthetic surfactant foam fire extinguishing agents, aqueous film-forming foam fire extinguishing agents, and protein foam fire extinguishing agents.

[0003] The most severe scenario for a fire occurring in a parking lot is one caused by the leakage or outflow of vehicle fuel (flammable liquid) such as gasoline. Therefore, foam fire extinguishing agents used in parking lots must be able to extinguish such flammable liquid leak fires.

[0004] Traditionally, aqueous film-forming foam fire extinguishing agents have been used in foam fire extinguishing systems for parking lots. While protein foam fire extinguishing agents generally have excellent heat resistance, they spread slowly when supplied in a foamed state onto the fuel surface, making them unsuitable for fire extinguishing. Synthetic surfactant foam fire extinguishing agents, while having excellent foaming ability, have low heat resistance, and the foamed agent spread onto the fuel surface is easily extinguished by the heat of the gasoline, resulting in a long time for fire extinguishing. Therefore, aqueous film-forming foam fire extinguishing agents, which have a fast foaming spread on the fuel surface and a well-balanced heat resistance against the fire, were ideal for parking lot applications.

[0005] The most important factor in ensuring the above-mentioned performance of aqueous film-forming foam fire-extinguishing agents is the incorporation of a fluorochemical surfactant (see, for example, Patent Document 1). However, the organic fluorine compounds contained in fluorochemical surfactants are difficult to decompose in nature and tend to remain and accumulate in the environment and ecosystems for long periods of time. Concerns about such environmental impacts have led to a global movement to restrict the use of organic fluorine compounds. In Japan, new production and sales of products containing three substances, PFOS, PFOA, and PFHxS (the six-carbon version of PFOS), are already restricted. It is expected that in the near future, PFOA-related substances, a group of substances that can be converted to PFOA through chemical reactions, PFHxA (the six-carbon version of PFOA), and related substances will also be subject to regulation, and eventually all organic fluorine compounds (PFAS) will be restricted.

[0006] In order to reduce surface tension and to meet various fire extinguishing performance requirements, aqueous film-forming foams use surfactants containing fluorine compounds as one of their components. In fact, it is generally believed in the industry that surfactants that do not contain fluorine compounds cannot meet the various performance requirements of aqueous film-forming foams. In other words, the prevailing view is that fluorine surfactants are a necessary component of aqueous film-forming foams.

[0007] However, if fluorosurfactants containing organic fluorine compounds become unusable, it will become impossible to manufacture aqueous film-forming fire-extinguishing foams. This means that there will be no fire-extinguishing foams suitable for use in parking lots. Therefore, there is an urgent need to develop alternative products that have the fire-extinguishing performance of fire-extinguishing foams for parking lots without using fluorosurfactants.

[0008] Japanese Patent Application Laid-Open No. 2007-252731

[0009] The inventors focused on synthetic interfacial fire-extinguishing foam agents that do not contain fluorine-based surfactants, and using the synthetic interfacial fire-extinguishing foam agent as the base for their formulation, they made various improvements to the foam's fire resistance, heat resistance, oil resistance, etc., and succeeded in developing a synthetic interfacial fire-extinguishing foam agent that is comparable in fire-extinguishing performance for parking lots to aqueous film-forming foam agents.

[0010] That is, the foam fire-extinguishing agent of the present invention is characterized by containing at least one selected from the group consisting of myristyl alcohol and lauryl alcohol. More specifically, the foam fire-extinguishing agent of the present invention preferably contains more than 0.0 mass% and not more than 1.3 mass% of myristyl alcohol. Also, the foam fire-extinguishing agent of the present invention preferably contains more than 0.0 mass% and not more than 1.7 mass% of lauryl alcohol. Furthermore, the foam fire-extinguishing agent of the present invention preferably contains more than 0.0 mass% and not more than 0.6 mass% of myristyl alcohol and more than 0.0 mass% and not more than 0.5 mass% of lauryl alcohol.

[0011] The fixed foam fire-extinguishing system of the present invention uses any one of the foam fire-extinguishing agents described above.

[0012] According to the present invention, it is possible to obtain a synthetic interface foam fire-extinguishing agent for parking lots whose fire-extinguishing performance is comparable to that of aqueous film-forming foam fire-extinguishing agents, and a fixed foam fire-extinguishing system using this foam fire-extinguishing agent.

[0013] 1 is a schematic diagram of a foam fire extinguishing equipment used in an experiment on a foam fire extinguishing agent. 2 is a diagram showing a fire extinguishing head used in an experiment on a foam fire extinguishing agent. 3 is a graph showing evaluation results regarding the state of a diluted liquid in an experiment on a foam fire extinguishing agent.

[0014] Representative embodiments of a foam fire extinguishing agent and a fixed foam fire extinguishing system using the same according to the present invention will be described in detail below with reference to the drawings. Note that the present invention is not limited to these drawings. Furthermore, since the drawings are intended to conceptually explain the present invention, dimensions, ratios, or numbers may be exaggerated or simplified as necessary to facilitate understanding.

[0015] The fire-extinguishing foam in this embodiment is based on a synthetic interface fire-extinguishing foam, which is composed primarily of a synthetic surfactant (e.g., a hydrocarbon surfactant) and contains added foam stabilizers such as glycol ethers and higher alcohols, antifreeze agents such as glycols, and anticorrosive agents.

[0016] The foam fire-extinguishing agent according to this embodiment contains at least one of the following higher alcohols, namely, myristyl alcohol and lauryl alcohol. Components other than the higher alcohols (myristyl alcohol and / or lauryl alcohol) include water, solvents, rust inhibitors, activators, pH stabilizers, pH adjusters, etc. More specifically, the foam fire-extinguishing agent according to this embodiment contains higher alcohols in a blending ratio described in any one of (1) to (3) below: (1) Myristyl alcohol: more than 0.0% by mass and not more than 1.3% by mass (2) Lauryl alcohol: more than 0.0% by mass and not more than 1.7% by mass (3) Myristyl alcohol: more than 0.0% by mass and not more than 0.6% by mass, and lauryl alcohol: more than 0.0% by mass and not more than 0.5% by mass

[0017] The applicant has confirmed that this formulation of the foam fire extinguishing agent according to this embodiment exhibits performance equivalent to or better than that of an aqueous film-forming foam fire extinguishing agent in a parking lot fire extinguishing performance test. In particular, a foam fire extinguishing agent containing 1.0% by mass of lauryl alcohol (0% by mass of myristyl alcohol) is suitable from the perspective of high fire extinguishing performance. That is, while synthetic surfactant foam fire extinguishing agents are generally considered to have poor fire resistance, heat resistance, and oil resistance, the above-described formulation changes improve the fire resistance, heat resistance, oil resistance, etc. of the foam, allowing for fire extinguishing performance equivalent to that of an aqueous film-forming foam fire extinguishing agent. If the formulation exceeds each upper limit, the long-term stability of the fire extinguishing agent is compromised, resulting in precipitation during long-term storage or cloudiness when the fire extinguishing agent is diluted with water.

[0018] However, due to the above-mentioned formulation changes (addition of higher alcohols and adjustment of other ingredients) to obtain the same fire extinguishing performance for parking lots as aqueous film-forming foam, the synthetic interface foam loses its performance when diluted with seawater and its high foaming ability. However, since diluting the fire extinguishing agent with seawater or using high foaming equipment is not anticipated for use in parking lots, there is no practical problem.

[0019] The foam fire extinguishing agent described above can be suitably used in foam fire extinguishing systems, particularly fixed foam fire extinguishing systems. Foam fire extinguishing systems spray an aqueous solution, a proportional mixture of water and fire extinguishing agent, as an air-containing foam from a foam outlet, covering the burning surface to shut out air and extinguishing the fire through a cooling effect. Foam fire extinguishing systems are intended for use with flammable liquids. In this embodiment, the system is particularly suitable for installation in areas used for parking.

[0020] A foam fire extinguishing system can be composed of a water source, a pressurized water supply device (fire pump), a foam fire extinguishing agent storage tank, a mixer, an automatic alarm device (water flow detection device, display device, alarm device, etc.), a foam outlet (foam head), a sensing head (closed sprinkler head), various fire extinguishing heads, piping and valves, an emergency power supply, etc. (See Figure 1, for example.) In a fixed foam fire extinguishing system, the foam head is placed on or around a structure such as an indoor parking lot.

[0021] The present invention will be described more specifically with reference to Examples and Comparative Examples. For the Examples and Comparative Examples, foam fire extinguishing agents A and B having the formulations shown in Tables 1 and 2 below were prepared.

[0022]

[0023]

[0024] The prepared foam fire extinguishing agents A and B were diluted to 2% and 3%, respectively, and the following fire extinguishing performance tests were conducted. (1) Test Method and Criteria The tests were conducted according to the test method and criteria stipulated in "Article 5: Effective Spray Range" of the "Technical Standards for the Installation and Maintenance of Foam Fire Extinguishing Equipment for Specific Parking Lots" (Fire and Disaster Management Agency Notification No. 5, March 28, 2014). Specifically, the standard stipulates that "after igniting the model and allowing one minute of pre-burning time, the fire must be extinguished within one minute and 30 seconds of the start of spraying." Therefore, the pass / fail criterion was set to extinguishment within one minute and 30 seconds. (2) Equipment Used The tests were conducted using the applicant's foam fire extinguishing equipment for specific parking lots. An outline of the foam fire extinguishing equipment used is shown in Figure 1. An outline of the fire extinguishing head used is also shown in Figure 2. (3) Results The fire extinguishing test results are shown in Table 3. As reference examples, the results of similar tests on an aqueous film-forming foam fire extinguishing agent (Alphafoam 310R; model numbers Foam Nos. 19 to 26) and a synthetic surfactant foam fire extinguishing agent (Profoam 310; model numbers Foam Nos. 51 to 24) that have passed national certification are also provided.

[0025]

[0026] As shown in Table 3, it was confirmed that the foam fire extinguishing agent according to this example has fire extinguishing performance equivalent to that of foam fire extinguishing agents that have passed the national examination.

[0027] It was confirmed that the foam extinguishing agent according to this example cleared the allowable ranges of the national certification standards of 6 times or more and 1 minute or more for the foam expansion ratio and 25% reduction time. It was also confirmed that the foam extinguishing agent according to this example satisfies all performance requirements of the synthetic interface foam extinguishing agent in the "Ministerial Ordinance Prescribing Technical Standards for Foam Extinguishing Agents" (Ministry of Home Affairs Ordinance No. 26, December 9, 1975), except for those related to seawater dilution and high foaming.

[0028] Furthermore, the same fire extinguishing performance test (R=2.6 m) was conducted on foam fire extinguishing agent A in Table 1, varying the amount of myristyl alcohol from 0.3% by mass to 3.0% by mass. A downward-facing fire extinguishing head was used. The test results are shown in Table 4.

[0029]

[0030] As shown in Table 4, increasing the amount of myristyl alcohol tends to shorten the fire extinguishing time. Furthermore, when the amount of myristyl alcohol exceeded 1.3% by mass, slight turbidity was observed when diluted with water, and when the amount of myristyl alcohol was 2.0% by mass or more, the fire extinguishing time tended to increase and the turbidity tended to become more pronounced with each increase in the amount of myristyl alcohol.

[0031] Furthermore, for foam fire extinguishing agent B in Table 2, the amount of lauryl alcohol blended was varied from 0.5% by mass to 1.7% by mass, and a fire extinguishing test (R = 2.6 m) was conducted. A downward-facing fire extinguishing head was used. The test results are shown in Table 5.

[0032]

[0033] As shown in Table 5, as with myristyl alcohol, increasing the amount of lauryl alcohol tends to shorten the fire extinguishing time. Furthermore, when the amount of lauryl alcohol exceeded 1.1% by mass, slight turbidity was observed when diluted with water, and when the amount of lauryl alcohol was 1.3% by mass or more, the fire extinguishing time tended to increase and the turbidity became more pronounced with each increase in the amount of lauryl alcohol.

[0034] For further examples, foam C was prepared according to the formulation shown in Table 6 below.

[0035]

[0036] The remaining 10% by mass of the foam fire extinguishing agent in Table 6 was made by adding myristyl alcohol and lauryl alcohol in the mass percentages shown in Table 7, and the remainder was made up by adding water, adjusting the foam fire extinguishing agent to a total of 100% by mass. The prepared foam fire extinguishing agent was diluted to 3% by mass with 50 g of fresh water, and the diluted water was placed in a thermostatic chamber at 20°C, and the state of the diluted solution after standing was observed. The results of diluting the foam fire extinguishing agent with the myristyl alcohol and lauryl alcohol contents shown in Table 7 with fresh water are shown below.

[0037] The test results in Table 7 confirm that the blending amounts of myristyl alcohol and lauryl alcohol that do not cause the diluted freshwater solution to become cloudy are more than 0.0% by mass and not more than 0.6% by mass of myristyl alcohol and more than 0.0% by mass and not more than 0.5% by mass of lauryl alcohol. It was also confirmed that when only myristyl alcohol is used, the blending amount is more than 0.0% by mass and not more than 1.0% by mass, and when only lauryl alcohol is used, the blending amount is more than 0.0% by mass and not more than 1.0% by mass.

[0038]

[0039] The evaluation results regarding the state of the diluted solution are shown in FIG. 3 for ease of understanding.

[0040] The above describes a foam fire extinguishing agent that is one embodiment of the present invention, but the present invention is not limited to these. Various design modifications are possible as long as the technical concept of the present invention is maintained, and all such design modifications are included in the technical scope of the present invention.

Claims

1. A foam fire extinguishing agent characterized by containing at least one member selected from the group consisting of myristyl alcohol and lauryl alcohol.

2. The foam extinguishing agent according to claim 1, characterized in that it contains more than 0.0% by mass and not more than 1.3% by mass of myristyl alcohol.

3. The foam extinguishing agent according to claim 1, characterized in that it contains more than 0.0 mass% and not more than 1.7 mass% lauryl alcohol.

4. The foam extinguishing agent according to claim 1, characterized in that it contains more than 0.0 mass% and not more than 0.6 mass% of myristyl alcohol and more than 0.0 mass% and not more than 0.5 mass% of lauryl alcohol.

5. A fixed foam fire extinguishing system using the foam fire extinguishing agent according to any one of claims 1 to 4.

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