Fire extinguishing composition suitable for multiple classes of fire

Abstract

The present invention relates to a fire extinguishing composition suitable for extinguishing multiple fire classes. More particularly, the composition comprises a phyllosilicate material; a pozzolanic material; a chemically inert salt powder; a binder; and a smoke suppressant. Advantageously, the composition does not conduct electricity and is safe to be applied on metal and electrical fire, such as an electric vehicle fire which includes lithium ion battery and other electrical components.

Description

[0001] FIRE EXTINGUISHING COMPOSITION SUITABLE FOR MULTIPLE

[0002] CLASSES OF FIRE

[0003] FIELD OF TECHNOLOGY

[0004] The present invention relates generally to a fire extinguishing composition. More particularly, the composition is suitable for use in extinguishing more than one classes of fire.

[0005] BACKGROUND OF THE INVENTION

[0006] Fire can be categorized into different classes based on the type of fuel source. According to the American Standard, Class A fires are caused by combustible solid materials such as wood, cloth, paper, rubber, and plastics; Class B fires are caused by flammable liquid and gases, such as petroleum greases, gasoline, tars, oils, alcohols, and the like; Class C fires are electrical fires caused by electrical components and energized electrical equipment such as wiring, machinery and appliances; Class D fires are caused by combustible metals such as magnesium, titanium, zirconium, sodium, lithium and potassium; and Class K fires are caused by combustible oils, fats, and grease specifically from cooking. On the other hand, according to the Australian standard, Class A fires are caused by combustible solid materials; Class B fires are caused by flammable liquids such as petrol, turpentine or paint; Class C fires are caused by flammable gases such as hydrogen, butane, methane; Class D fires are caused by combustible metals such as magnesium, aluminium or potassium; Class E fires are caused by electrical equipment; and Class F fires are caused by cooking oils.

[0007] Apparently, different classes of fires require different extinguishing agents for effective extinguishment. Applying a wrong extinguishing agent may be dangerous and may even cause the fire to burn with increased intensity. Further, in a real situation, multiple classes of fires may occur in a scene. Hence, a fire extinguishing agent which is able to work on more than one classes of fires is necessary.

[0008] China Patent Application Publication No. CN 108159622 A disclosed an ammonium phosphate ABC dry powder extinguishing agent. Particularly, it is applicable to extinguish Class A, B and C fires. Particularly, the extinguishing agent comprises raw materials of, by weight, 120-160 parts of monoammonium phosphate, 30-40 parts of ammonium nitrate, 10-20 parts of calcined kaolin, 6-12 parts of bentonite, 4-6 parts of borax, 1-2 parts of manganese chloride, 0.6-1.2 parts of calcium nitrate, 6-10 parts of pentaerythritol, 4-8 parts of melamine, 1-2 parts of dimethyl di ethoxysilane and 4-8 parts of methyl silicone oil.

[0009] The emergences of electric vehicle industry has widen the use of lithium-ion batteries (LiBs). Conventionally, a fire caused by combustion of lithium-ion batteries belongs to Class A, B, C, D and E fires. Class A fire is caused by the combustion of graphite anode, polymeric separator and plastic casing of LiBs. Class B fire is caused by the combustion of liquid electrolytes and fluorinated solvents in LiBs. Class C fire is caused by the combustion of hydrocarbon vapours released. Class D fire is caused by lithium metal oxide cathodes and lithium metal dendrites while Class E fire is caused by the energised electrical system of LiBs. Conventional ammonium phosphate-based powder for Class A, B and C fires (Australian standard) are not suitable to extinguish Class D fire. Metal fire usually burns at temperature higher than 600 °C which is higher than the decomposition temperature of ammonium phosphate-based powders. At this temperature range, ammonium phosphate-based powders decompose to release ammonia and phosphoric acid. Ammonia is highly explosive while phosphoric acid will combust to form toxic fumes of phosphorus oxide and also attack metals to form explosive hydrogen gas. Replacement of ammonium phosphate-based powder is necessary for safety purposes and also to kill metal fires. Further, a fire caused by ignition of lithium-ion batteries in an electric vehicle involves a lot of other electrical components. Hence, a fire extinguishing agent which is able to extinguish multiple classes of fire, and being safe to put out fires caused by combustion of metal and electrical components, are necessary.

[0010] Patent Cooperation Treaty Patent Application Publication No. WO 99 / 26698 Al disclosed a multipurpose dry powder of extinguishing agent for class A, B, C, and D fires. More particularly, the dry powder comprises 50 to 80 wt % of ammonium sulfate, 5 to 30 wt % of ammonium dihydrogen phosphate, 5 to 20 wt % of sodium chloride, 1.5 to 3 wt % of mica powder, 1.5 to 3 wt % of active clay, 2.5 to 5 wt % of permeating promotor of alkali metal salts of sulfuric acid, 1.5 to 3 wt % of water repellent silica powder, 1.5 to 4 wt % of hydrophobic white carbon, and 0.2 to 0.5 wt % of organosilicone. It was disclosed that the dry powder composition can extinguish Class A, B, C, and D fires, as well as electrical fires with no corrosion. However, this composition relies on ammonium phosphate-based and sulfate-based powders which, at high temperature of fires, will decompose to release ammonia, phosphoric acid, sulfur dioxide and sulfuric acid which are explosive and toxic. This invention provides a solution to the abovementioned drawbacks to handle high- temperature and multi -class fire scenarios.

[0011] SUMMARY OF THE INVENTION

[0012] One aspect of the present invention is to provide a dry powder composition applicable as fire extinguisher to more than one classes of fire. For example, the composition is applicable to extinguish fire caused by lithium ion battery in an electric vehicle.

[0013] Another aspect of the present invention is to provide a dry powder composition which is not electrically conductive, hence suitable to extinguish electrical fire such as those in Class E based on AU standard.

[0014] Another aspect of the present invention is to provide a fine, porous, and lightweight dry powder composition. This enables design of a lightweight fire extinguisher to put out fire with comparable or higher efficiency. For example, the powder composition provides a higher or equivalent fire extinguishing capacity by using similar or lesser amount of material as compared to a conventional fire extinguishing composition.

[0015] Another aspect of the present invention is to provide a dry powder composition applicable in a portable extinguisher. For example, the composition can be filled in a portable gas cartridge type of fire extinguisher, wherein the composition can be discharged by applying a pressure of about 1400 to about 2000 kPa via pressurized gas, such as but not limited to, nitrogen, carbon dioxide or other inert, pressurizable gases.

[0016] Another aspect of the present invention is to provide a dry powder composition having satisfactory flowability and hygroscopicity. Preferably, the dry powder is provided in an average particle size in micron range of about 50 pm to 500 pm to prevent powder segregation hence providing flowability upon discharged.

[0017] At least one of the preceding aspects is met, in whole or in part, by the present invention, in which one of the embodiments of the present invention is a fire extinguishing composition suitable for extinguishing more than one type of fire, comprising: a phyllosilicate material; a pozzolanic material; a chemically inert salt powder; a binder; and a smoke suppressant.

[0018] Preferably, the phyllosilicate material is selected from the group consisting of serpentinite, clay mineral, and mica.

[0019] Preferably, the pozzolanic material is selected from the group consisting of fly ash, ground granulated blast furnace slag, silica fume, pyrogenic silica, metakaolin, and volcanic ash.

[0020] Preferably, the salt powder is an organometallic salt, a metallic salt, an inorganic salt, or a mixture of two or more thereof. Preferably, the organometallic salt is derived from a metal cation and an organic anion, wherein the metallic cation is selected from any one or a combination of any two or more of sodium ion, calcium ion, magnesium ion, aluminium ion, potassium ion, lithium ion, copper ion, iron ion, and titanium ion; and the organic anion is selected from any one or a combination of any two or more of acetate, oxalate, oleate, linoleate, stearate, citrate, tartrate, or salicylate.

[0021] Preferably, the metallic salt is derived from a metal cation and an inorganic anion, wherein the metallic cation is selected from any one or a combination of any two or more of sodium ion, calcium ion, magnesium ion, aluminium ion, potassium ion, lithium ion, copper ion, iron ion and titanium ion; and the inorganic anion is selected from any one or a combination of any two or more of carbonate, chloride, phosphate, sulfate, nitrate, chloride, hydroxide, sulfite, or thiosulfate.

[0022] Advantageously, the binder is hypromellose.

[0023] Advantageously, the smoke suppressant is selected from any one or a combination of any two or more of zinc oxide, zinc stannate, hydrotalcites, or aluminium hydroxide.

[0024] Preferably, the composition is in a powder form having a particle size ranging from 50 pm to 500 pm. In one embodiment, the phyllosilicate material and the pozzolanic material are provided in an average particle size of about 50 pm to 300 pm whereas the chemically inert salt powder is provided in an average particle size of about 200 pm to 500 pm.

[0025] In one embodiment, the composition comprises a phyllosilicate material in 20 to 60 wt% of the total composition; a pozzolanic material in 5 to 10 wt % of the total composition; a chemically inert salt powder in 20 to 30 wt % of the total composition; a binder in 1 to 3 wt % of the total composition; and a smoke suppressant in 1 to 3 wt % of the total composition.

[0026] DETAILED DESCRIPTION OF THE INVENTION

[0027] Exemplary, non-limiting embodiments of the invention will be disclosed. However, it is to be understood that limiting the description to the preferred embodiments of the invention is merely to facilitate discussion of the present invention and it is envisioned that those skilled in the art may devise various modifications without departing from the scope of the appended claim.

[0028] In the present invention, the fire extinguishing composition comprises a phyllosilicate material; a pozzolanic material; a chemically inert salt powder; a binder; and a smoke suppressant. In one embodiment, the fire extinguishing composition comprises a phyllosilicate material in 20 to 60 wt% of the total composition; a pozzolanic material in 5 to 10 wt % of the total composition; a chemically inert salt powder in 20 to 30 wt % of the total composition; and remainder being a binder and a smoke suppressant. In another embodiment, the composition comprises a phyllosilicate material in 20 to 60 wt% of the total composition; a pozzolanic material in 5 to 10 wt % of the total composition; a chemically inert salt powder in 20 to 30 wt % of the total composition; a binder in 1 to 3 wt % of the total composition; and a smoke suppressant in 1 to 3 wt % of the total composition.

[0029] Phyllosilicate material exists in sheet form where each sheet consists of two tetrahedral layers with an intermediate octahedral layer. Phyllosilicate, in its natural form, is hydrated with the water molecules and hydroxyl groups attached to the aforementioned sheets. This gives phyllosilicate a very high thermal absorption capacity. When phyllosilicate is exposed to a heat source, it absorbs significant heat from the source to vaporise its internal water molecules and break the hydroxyl bonds between the sheets. As the water molecules vaporise, they expand and push the sheets apart causing the phyllosilicate to undergo exfoliation. The exfoliated phyllosilicate, or also known as expanded phyllosilicate, has an expanded and porous structure that is highly filled with air that provides high thermal insulation. In the present invention, phyllosilicate material is provided in the composition to extract significant heat from a combustion source via the aforementioned processes.

[0030] Preferably, the phyllosilicate material is selected from the group consisting of serpentinite, clay mineral, and mica. The phyllosilicate material used can be selected from a single phyllosilicate material, or a mixture of two or more phyllosilicate materials. Accordingly, examples of serpentinite include antigorite, chrysotile, and lizardite. Examples of clay mineral include halloysite, kaolinite, pyrophyllite, talc, illite, montmorillonite, chlorite, vermiculite, sepiolite, and palygorskite. Examples of mica include biotite, fuchsite, muscovite, phlogopite, lepidolite, margarite, and glauconite. In one embodiment, the composition comprises a phyllosilicate material in 20 to 60 wt% of the total composition, wherein the phyllosilicate material used is vermiculite. In another embodiment, the composition comprises a phyllosilicate material in 20 to 60 wt% of the total composition, wherein the phyllosilicate material used is a combination of vermiculite and kaolinite in equal parts.

[0031] Pozzolanic material are siliceous and aluminous materials. It is preferred that the pozzolanic material used has a cenosphere form which is obtained from a high temperature combustion of the material. The cenosphere resembles a hollow sphere which enables it to contain significant amount of air, hence it exhibits high thermal insulation while being lightweight. The material in such form is highly refractory in nature which can draw significant heat from a combustion source during occurrence of fire. Preferably, the pozzolanic material is selected from the group consisting of fly ash, ground granulated blast furnace slag, silica fume, pyrogenic silica, metakaolin, and volcanic ash. The pozzolanic material used can be selected from a single pozzolanic material, or a mixture of two or more pozzolanic materials. In one embodiment, the pozzolanic material is provided in 5 to 10 wt % of the total composition, wherein the pozzolanic material used is metakaolin. In another embodiment, the composition comprises a pozzolanic material in 5 to 10 wt% of the total composition, wherein the pozzolanic material used is a combination of metakaolin and ground granulated blast furnace slag with equal parts.

[0032] Salt is highly refractory, incombustible and chemically inert. Hence, salt can extract significant heat from a combustion source without undergoing further reaction or degradation. It is preferred to treat a metal fire with the corresponding metal salt. For example, to use lithium-containing salt in extinguishing a lithium metal fire. Hence, the present invention includes a salt powder to cover a metal fire. In the present invention, the composition further comprises a chemically inert salt powder in 20 to 30 wt % of the total composition. Preferably, the salt powder is an organometallic salt, a metallic salt, or a mixture thereof.

[0033] The organometallic salt is derived from a metallic cation and an organic anion, wherein the metallic cation is selected from any one or a combination of any two or more of sodium ion, calcium ion, magnesium ion, aluminium ion, potassium ion, lithium ion, copper ion, iron ion and titanium ion; and the organic anion is selected from any one or a combination of any two or more of acetate, oxalate, oleate, linoleate, stearate, citrate, tartrate, or salicylate. Examples of the organometallic salt includes sodium acetate, magnesium oxalate, aluminium stearate, and et cetera.

[0034] The metallic salt is derived from a metal cation and an inorganic anion, wherein the metallic cation is selected from any one or a combination of any two or more of sodium ion, calcium ion, magnesium ion, aluminium ion, potassium ion, lithium ion, copper ion, iron ion and titanium ion; and the inorganic anion is selected from any one or a combination of any two or more of carbonate, chloride, phosphate, sulfate, nitrate, chloride, hydroxide, sulfite, or thiosulfate. Examples of the metallic salt includes calcium carbonate, magnesium chloride, aluminium thiosulfate, and et cetera. Accordingly, the phyllosilicate material is preferably provided in fine powder form to ease its penetration through combusting materials, hence able to draw out heat effectively from the heat source. Further, the fine powder form provides good flowability upon discharged from a fire extinguisher. In one embodiment, the phyllosilicate material is provided in an average particle size of about 50 pm to 300 pm, more preferably 200 pm to 300 pm. Accordingly, the pozzolanic material is provided in an average particle size of about 50 pm to 300 pm, more preferably 100 pm to 200 pm. Further, the chemically inert salt powder is provided in an average particle size of about 200 pm to 500 pm, more preferably 300 pm to 400 pm. The phyllosilicate material and the pozzolanic material are ground into the preferred size such that they can achieve a comparable bulk density with the salt powder. As such, powder segregation can be minimized.

[0035] In the present invention, the composition further comprises a binder to prevent segregation of the dry powder and to absorb moisture. Preferably, the binder used is hypromellose in the form of powder. In one embodiment, the hypromellose is present in 1 to 3 wt % of the total composition.

[0036] Further, the composition comprises a smoke suppresant capable of suppressing oxidation reaction of free radicals such as H*, OH* and O*. Advantageously, the smoke suppressant is selected from any one or a combination of any two or more of zinc oxide, zinc stannate, hydrotalcites, or aluminium hydroxide. Preferably, the smoke suppressant is provided in the form of powder. Advantageously, the smoke suppressant is present in 1 to 3 wt % of the total composition.

[0037] The composition can be prepared via mechanical mixing of the powder components according to the specified weight percentages. According to the preceding description, the phyllosilicate material, the pozzolanic material and the salt powder can be ground to the preferred size before mixing. The composition can be packed into sealed pouches or cartridges. Due to its lightweight and flowability, the composition can be used in a portable fire extinguisher, can be configured into a fire retarding pouch, or the like. Alternatively, the composition can be stored inside a fire extinguishing system of a facility, such as vehicle parking lots, but not limited thereto.

[0038] Example 1 provides test results of the composition in present invention.

[0039] EXAMPLE 1

[0040] • Test 1 : 5 kg of phyllosilicate flake (3-5 mm size) can extinguish Mg fire (0.5 kg) in around 5 minutes.

[0041] • Test 2: 5 kg of phyllosilicate powder (500 micron) can extinguish Mg fire (0.5 kg) in around 2 minutes. When compare with Test 1, finer phyllosilicate will require lesser amount to extinguish the equal amount of combustible material.

[0042] • Test 3: 2 kg of phyllosilicate powder (300 micron) can extinguish Mg fire (0.5 kg) in around 1.5 minutes. Finer phyllosilicate powder can kill fire faster.

[0043] • Test 4: 2 kg of phyllosilicate powder (300 micron) with 1% of smoke suppression additive can extinguish Mg fire of same amount and duration but with lesser smoke formation.

[0044] • Test 5: 5 kg of powder with 57 wt% of phyllosilicate, 10 wt% of pozzolanic powder, 27 wt% of metallic salt (lithium oxide, sodium bicarbonate, magnesium stearate in equal parts), 3 wt% of hypromellose and 3 wt% of zinc oxide can extinguish fire from 1.0 kWh lithium ion battery (pouch form) within 3 minutes.

[0045] The present invention may be embodied in other specific forms without departing from its essential characteristics. The described embodiments are to be considered in all aspects only as illustrative and not restrictive. The scope of the invention is, therefore indicated by the appended claims rather than by the foregoing description. All changes, which come within the meaning and range of equivalency of the claims, are to be embraced within their scope.

Claims

CLAIMS1. A fire extinguishing composition suitable for extinguishing multiple fire classes, comprising: a phyllosilicate material; a pozzolanic material; a chemically inert salt powder; a binder; and a smoke suppressant.

2. The composition according to claim 1 wherein the phyllosilicate material is selected from the group consisting of serpentinite, clay mineral, and mica.The composition according to claim 1 wherein the pozzolanic material is selected from the group consisting of fly ash, ground granulated blast furnace slag, silica fume, pyrogenic silica, metakaolin, and volcanic ash.

3. The composition according to claim 1 wherein the salt powder is an organometallic salt, a metallic salt, or a mixture thereof.

4. The composition according to claim 4, wherein the organometallic salt is derived from a metallic cation and an organic anion, wherein the metallic cation is selected from any one or a combination of any two or more of sodium ion, calcium ion, magnesium ion, aluminium ion, potassium ion, lithium ion, copper ion, iron ion and titanium ion; and the organic anion is selected from any one or a combination of any two or more of acetate, oxalate, oleate, linoleate, stearate, citrate, tartrate, or salicylate.

5. The composition according to claim 4, wherein the metallic salt is derived from a metal cation and an inorganic anion, wherein the metallic cation is selected from any one or a combination of any two or more of sodium ion, calcium ion, magnesium ion, aluminium ion, potassium ion, lithium ion, copper ion, iron ion and titanium ion; and the inorganic anion is selected from any one or a combination of any two or more of carbonate, chloride, phosphate, sulfate, nitrate, chloride, hydroxide, sulfite, or thiosulfate.

6. The composition according to claim 1, wherein the binder is hypromellose.

7. The composition according to claim 1, wherein the smoke suppressant is selected from any one or a combination of any two or more of zinc oxide, zinc stannate, hydrotalcites, or aluminium hydroxide.

8. The composition according to any one of claims 1 to 7 is in a powder form having a particle size ranging from 50 pm to 500 pm.

9. The composition according to any one of claims 1 to 8 comprises: a phyllosilicate material in 20 to 60 wt% of the total composition; a pozzolanic material in 5 to 10 wt % of the total composition; a chemically inert salt powder in 20 to 30 wt % of the total composition; a binder in 1 to 3 wt % of the total composition; and a smoke suppressant in 1 to 3 wt % of the total composition.