JPS6370B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a safe and quickly extinguishing fire extinguishing agent composition that is emitted in spray form from a pressure vessel. In recent years, the number of tempura oil fires in homes has increased dramatically. This tempura oil has a general composition of esters consisting of glycerin and various saturated or unsaturated fatty acids, and has a normal usage temperature of 170 -
At 190℃, there is no risk of ignition even if a pilot flame is brought close. However, when heated above the flash point of approximately 260 degrees Celsius, steam and decomposition gas from the tempura oil will come out from the surface, which will easily ignite when brought close to the pilot flame, and will further exceed the ignition point of approximately 360 degrees Celsius. and,
A large amount of steam and decomposed gas from the tempura oil is generated, which can ignite and cause a fire even without a pilot flame. By the way, conventional extinguishing agents can be roughly divided into gas-based, evaporative liquid-based, powder-based, water-based, and foam-based, and these have their own characteristics depending on the object of fire. However, when tempura oil burns above its ignition point, it is difficult for any of these extinguishing agents to satisfactorily extinguish the fire, as described below. In other words, gas-based extinguishing agents such as carbon dioxide extinguishing agents, and evaporative liquid-based extinguishing agents such as monobromide trifluoride methane, monobromide monochloride difluoride methane, dibromide tetrafluoride ethane, etc. , it is possible to extinguish a tempura oil fire while it is being radiated, but it does not have the cooling effect of lowering the temperature of tempura oil below its ignition point, nor does it have the effect of suppressing the release of flammable vapor from tempura oil. If the fire is stopped, the fire will re-ignite immediately and cannot be extinguished. In addition, powder-based fire extinguishers whose main ingredients are alkali bicarbonate or the reaction product of alkali bicarbonate and urea slightly saponify the tempura oil and form a thin film on the surface of the tempura oil. However, this film does not go so far as to suppress the release of flammable vapor from the tempura oil, and like the gas-based extinguishing agents and evaporative liquid-based extinguishing agents mentioned above, it does not have a cooling effect, so it does not prevent re-ignition. A considerable amount of powder is required to prevent this, and the amount normally filled in a fire extinguisher used at home is insufficient. Furthermore, foam-based fire extinguishing agents, such as protein foam fire extinguishing agents, synthetic interfacial foam fire extinguishing agents, and aqueous film-forming foam fire extinguishing agents, have excellent cooling effects on tempura oil and suppressing flammable vapors. However, it is extremely dangerous as it can fan the flames (flashover phenomenon) and scatter tempura oil when emitting foam. Compared to the above four types of extinguishing agents, a reinforced liquid extinguishing agent whose main agent is potassium carbonate, which is one of the representative examples of water-based extinguishing agents, has a saponification effect because the main agent potassium carbonate is more alkaline than alkali bicarbonate. This enhanced liquid fire extinguisher is considered to be relatively effective against tempura oil fires because it is somewhat strong and can suppress the release of flammable vapor to some extent, and also has the cooling effect of tempura oil. However, the suppressing effect on flammable vapors is still insufficient to completely prevent re-ignition, and the potassium carbonate content is 30% by weight.
It is a concentrated solution containing the above, with a pH of 12.4 or higher, which is highly alkaline and poses a danger to humans and livestock, so it is far from satisfactory as a fire extinguisher. The present invention has been made in view of the above circumstances, and is effective in extinguishing fires A (ordinary fire), fire B (oil fire), and fire C (electrical fire) stipulated in the Fire Service Act, as well as fires that have been occurring frequently in recent years. The present invention aims to provide a weakly alkaline fire extinguishing agent composition that can safely and quickly extinguish tempura oil fires and sufficiently prevent re-ignition. That is, the fire extinguishing composition of the present invention has 6 to 15% by weight of an alkali bicarbonate and 2 to 10% by weight of a borate dissolved in water as main ingredients, and is sprayed from a pressure vessel in the event of a fire. It extinguishes fire by emitting radiation. A solution prepared by dissolving alkaline bicarbonate alone in a solvent such as water is weakly alkaline, and as mentioned above, it slightly saponifies tempura oil and forms a thin film on the surface of tempura oil. It does not work to form strong and durable bubbles on the surface of the tempura oil that can completely suppress the release of flammable vapors, nor does it work to lower the temperature of the tempura oil below its ignition point. Furthermore, a solution of borate alone does not have the above effect. However, as in the present invention, alkali bicarbonate 6~
A fire extinguishing agent composition made by mixing 15% by weight and 2 to 10% by weight of borate and dissolving it in water can be used to destroy tempura oil burning at a high temperature above the ignition point by just emitting a small amount in spray form. Rapidly forms strong and durable foam on the surface, instantly extinguishing tempura oil fires and suppressing the release of flammable vapors from tempura oil.
Re-ignition after radiation can be sufficiently prevented. This was the first discovery made by the inventor after various studies, and is probably because the saponification of tempura oil by alkali bicarbonate is significantly accelerated by the coexisting borate. It is assumed that a foam strong and durable enough to completely suppress the release of flammable vapors would form rapidly. As the alkali bicarbonate salt used in the present invention, water-soluble alkali bicarbonate salts such as _potassium bicarbonate and _sodium bicarbonate are suitable _. [However, M in the formula
represents an alkali metal, and m takes a value between 1 and 4. For example, potassium borate,
Water-soluble borates such as sodium borate and potassium tetraborate are preferred. As shown in the examples below, the content of these is approximately 6 to 15% by weight for alkali bicarbonate and approximately 2 to 10% by weight for borate.
be within the range of This is because if the amount of alkali bicarbonate is less than 6% by weight and the amount of borate is less than 2% by weight, there will be a shortage of alkali bicarbonate and the borate will not have a significant saponification promoting effect. Therefore, it becomes difficult to form a sufficient amount of bubbles on the surface of tempura oil. Conversely, if the alkali bicarbonate content exceeds 15% by weight and the borate content exceeds 10% by weight, an excessive amount of bubbles may form. This is because there is a disadvantage that there is waste formed and the alkalinity of the extinguishing agent itself becomes somewhat stronger. The fire extinguishing agent composition of the present invention contains an alkali bicarbonate and a borate that promotes saponification as main ingredients as described above, but desirably does not cause a chemical reaction between these main ingredients. Carboxymethyl cellulose, polyvinyl alcohol, polysaccharides,
It is preferable to further add one or more thickeners selected from the group consisting of alginates. This is because when such a thickener is added, the foam layer formed on the surface of tempura oil becomes stronger and more durable. Incidentally, it is sufficient to add such a thickening agent in a very small amount of less than 1% by weight. Furthermore, the fire extinguishing composition of the present invention may contain an antifreeze agent such as urea for the purpose of lowering the freezing point, or may contain ammonium sulfate, ammonium sulfamate, and ammonium phosphate for the purpose of increasing the ability to extinguish A fires stipulated in the Fire Service Act. Of course, it is also possible to add an alkali salt of an organic acid such as citric acid, acetic acid, or tartaric acid or an alkali halide salt for the purpose of increasing the ability to extinguish B fires specified in the Fire Service Act. Since all of these additives are free from the risk of reducing the saponification effect or fire extinguishing power, the amount to be added can be freely determined depending on the purpose. Next, the fire extinguishing agent composition of the present invention will be explained with reference to Examples. Examples 1 to 6 Six types of fire extinguishing agent compositions having the composition ratios shown in Table 1 below were prepared, and 300 g of each composition was filled into an aerosol type simple fire extinguisher, pressurized with liquefied gas, and heated in the following manner. We conducted a fire extinguishing test for a tempura oil fire. Pour 700ml of soybean oil (with an ignition point in the range of 360 to 370℃) into a wok with a diameter of 30cm and a depth of 7.5cm, heat it to 400℃ on a gas stove, and burn the soybean oil.
After extinguishing the fire on the gas stove, start spraying a fire extinguishing agent composition from a fire extinguisher or a simple aerosol fire extinguisher, and after extinguishing the fire, continue spraying for another 5 seconds, and then check whether there is any re-ignition and the surface of the tempura oil. I observed the condition. The results of this fire extinguishing test are shown in Table 2 below. Furthermore, when each of the fire extinguishing agent compositions was filled into a Type 3 fire extinguisher and subjected to the A-1 unit and B-2 unit fire extinguishing tests stipulated in the Fire Service Act, all compositions passed. Comparative Examples 1 to 3 A test for extinguishing a tempura oil fire was carried out in the same manner as in the above example for three types of fire extinguishing agent compositions having the composition ratios shown in Table 1 below. The results are shown in the second section below.
It is also shown in the table.

【table】

【table】

[Table] Looking at Table 1 above, it can be seen that the fire extinguishing agent composition of the present invention is a low concentration solution containing alkali bicarbonate and borate as main ingredients, and the conventional reinforced liquid extinguishing agent of concentrated acid potassium solution (compared to It can be seen that it is far less alkaline than Example 3) and is less likely to pose a danger to humans and livestock. And if you look at Table 2, about 200
Even though the amount used is small (less than 1 gram), it extinguishes the fire within seconds and forms a thick layer of foam on the surface of the tempura oil, suppressing the release of flammable vapor from the tempura oil and completely preventing re-ignition. It can be seen that the fire extinguishing agent composition has excellent fire extinguishing ability and re-ignition prevention ability.

Claims (1)

[Scope of Claims] 1. 6 to 15% by weight of alkali bicarbonate and borate 2.
A fire extinguishing agent composition characterized in that ~10% by weight is dissolved in water as a main agent. 2. The fire extinguishing composition according to claim 1, which contains one or more thickeners selected from the group consisting of carboxymethyl cellulose, polyvinyl alcohol, polysaccharides, and alginates.