FIRE SUPPRESSANT MATERIAL

Abstract

Disclosed is a fire suppressant material for controlling or extinguishing a combustion process, the fire suppressant material comprising zeolite particles with an internal porous structure, wherein molecules of a fire extinguishing substance are contained within the internal porous structure of the zeolite material.

Claims

1. A fire suppressant material for controlling or extinguishing a combustion process, the fire suppressant material comprising: zeolite particles having an internal porous structure; and, molecules of a fire extinguishing substance which are contained within the internal porous structure of the zeolite particles.

2. A fire suppressant material according to claim 1, wherein the molecules of the fire extinguishing substance are either carbon dioxide or water.

3. A fire suppressant material according to claim 1 or 2, wherein the pore size of the internal porous structure of the zeolite particles is selected to preferentially absorb carbon dioxide over nitrogen or oxygen.

4. A fire suppressant material according to any one of the preceding claims, wherein pores of the internal porous structure are substantially consistent in size and shape.

5. A fire suppressant material according to any one of the preceding claims, wherein the material is configured or adapted to activate and release the molecules of fire extinguishing substance upon absorption of heat generated in a combustion process.

6. A fire suppressant material according to claim 5 wherein the activation occurs at a temperature up to 80° C., or up to or around 200° C., or up to or around 300° C.

7. A fire suppressant material according to any one of the preceding claims, wherein the material is configured or adapted (such as via storage of the zeolite under conditions to absorb the maximum CO.sub.2, e.g., at 1 atmosphere of CO.sub.2) such that activation upon absorption of heat results in release of a volume of molecules of fire extinguishing substance that is 100 - 200 times greater than the volume of the zeolite particles.

8. A fire suppressant material according to any one of the preceding claims, wherein the material is configured to absorb CO.sub.2 from the atmosphere and release this gas when exposed to heat, e.g., up to 80° C.

9. A fire suppressant material according to any one of the preceding claims wherein the material is capable of being regenerated on exposure to the atmosphere or an alternative source of the fire extinguishing molecules.

10. A fire suppressant material according to claim 9, wherein the material is able to absorb the fire extinguishing substance from the atmosphere or the source of the extinguishing molecules.

11. A fire suppressant material according to any one of claims 1-10, wherein the zeolite particles comprise zeolite 5A particles and/or zeolite 3A or 4A particles.

12. A product for protecting a surface from a combustion process, the product comprising the fire suppressant material of any one of the preceding claims.

13. A method for protecting a surface from a combustion process, the method comprising the steps of: depositing a protective material onto the surface, the protective material comprising zeolite particles with an internal porous structure having molecules of a fire extinguishing substance contained in the internal porous structure of the zeolite particles.

14. A method for protecting a surface from a combustion process, the method comprising the step of: depositing a fire suppressant material according to any one of claims 1-10 onto the surface.

15. A method as defined in claim 13 or claim 14, wherein the zeolite particles are dispersed in a solvent.

16. A method as defined in any one of claims 13-15, wherein the fire suppressant material is designed or adapted to activate and release the extinguishing substance at up to 80° C., or up to 300° C.

17. A method as defined in any one of claims 13-16, wherein the fire suppressant material is formulated to suppress ignition of fires or protect against ember attack.

18. A method of improving a fire suppressant system comprising the step of: adding the fire suppressant material of any one of claims 1 to 10 to a direct fire suppressant system.

19. A method of suppressing a fire comprising the step of: applying the fire suppressant material of any one of claims 1-10 directly to the fire.

20. A method of forming a barrier to fire comprising the step of: applying the fire suppressant material of any one of claims 1-10 to the area where a barrier to fire is required.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Embodiments will now be described by way of example only, with reference to the accompanying drawings in which:

[0039] FIG. 1 is a schematic which illustrates one embodiment of a method of using the fire suppressant material of the invention to protect a surface;

[0040] FIG. 2 is a representation of the fire suppressant material of the invention in the form of zeolite particles;

[0041] FIG. 3 is a scanning electron micrograph of the fire suppressant material of the invention in the form of zeolite particles.

[0042] FIG. 4 are photographs of two examples of commercially available zeolites showing the varying shapes and sizes that are manufactured. These examples are in the size range of 1-5 mm.

[0043] FIG. 5 demonstrates fire suppressant properties of the fire suppressant material of the invention in the form of zeolite 5A. A piece of burning wood (FIG. 5A) is treated with zeolite 5A particles (in this case by distributing a small quantity over the surface of the burning wood surface) equilibrated with 1 atm CO.sub.2, and totalling ⅒th the weight of the piece of burning wood. This results in the fire being rapidly extinguished (FIG. 5B). The efficacy and speed with which the fire was suppressed and extinguished was a surprising outcome, and was within seconds.

[0044] FIGS. 6A and 6B demonstrate the fire suppressant properties of the fire suppressant material of the invention by immediately extinguishing a large burning wooden ember.

DETAILED DESCRIPTION

[0045] In the following detailed description, reference is made to accompanying drawings which form a part of the detailed description. The illustrative embodiments described in the detailed description, depicted in the drawings and defined in the claims, are not intended to be limiting. Other embodiments may be utilised and other changes may be made without departing from the spirit or scope of the subject matter presented. It will be readily understood that the aspects of the present disclosure, as generally described herein and illustrated in the drawings can be arranged, substituted, combined, separated and designed in a wide variety of different configurations, all of which are contemplated in this disclosure.

[0046] Referring to FIG. 1, the fire suppressant material of the invention 10 (in the form of a coating layer) is shown in use on a substrate 22. Upon activation, the fire suppressant material 10 reduces the available heat and oxygen in order to control or extinguish or suppress a fire or an ember. A well-known method to reduce oxygen availability is to smother a fire with an inert gas, such as carbon dioxide. The disclosed material employs a process of physisorption to store an inert gas until required. Physisorption involves the formation of weak bonds using forces such as for example van der Waals forces between two materials. In this way, a gas molecule may for example be bound to the surface of another material (usually a solid). Physisorption is also a reversible process that can be reversed by the application of sufficient energy to break the bond (usually in the form of heat).

[0047] As shown in FIG. 1, the fire suppressant material 10 may be effective in combating ember attack from a bushfire. When located in proximity to an ember 20, the fire suppressant material 10 may absorb the heat from the ember and be activated to release the fire extinguishing substance from the fire suppressant material. In some forms, that fire extinguishing substance comprises carbon dioxide molecules and/or water molecules or alternative extinguishing substances. For example, the release of a large number of carbon dioxide molecules results in the formation of a blanket of carbon dioxide gas 24 around the ember that effectively prevents access to oxygen for the ember to substantially or completely extinguish it. It has been surprisingly found that even if the ember is oxygen-deprived for a short period of time, this is sufficient for the ember to be substantially or completely extinguished. Simultaneously, the absorption of heat by the fire suppressant material 10 from the ember 20 helps to prevent transfer of this heat to the surface 22 (e.g., wood or other combustible materials). In this manner, the heat of the ember 20 is prevented from increasing the temperature of the surface 22 to beyond its ignition temperature (for example the ignition temperature for paper is 233° C.). The combined action of preventing access to oxygen and absorption of heat effectively stops the ember 20 from undergoing further combustion. The efficacy and speed with which the material of the invention is able to suppress and extinguish a fire or an ember was a surprising outcome. A further surprising outcome of the invention is that the fire suppressant material is self-regulating, in the respect that more or less fire extinguishing substance is released depending on the need (i.e., the temperature the fire suppressant material is exposed to). This provides an ability for the fire suppressant material of the invention to have some ‘longevity’ in resisting a fire, in that it only delivers enough fire extinguishing substance that is required. Additionally, different zeolite particles can have different temperature ranges at which they release a fire extinguishing substance, and hence different applications are contemplated herein. It is worth noting that there are around 250 types of zeolite structures which are possible, and selection of the appropriate zeolite is not a straightforward consideration. For example, in order to protect a roof from fires caused by ember/electrical issues, two layers of fire suppressant material with different releasing temperatures could be used in the roof cavity. As an example, a ‘top’ layer could release CO.sub.2 at about 80° C. and if the fire persists, a ‘bottom’ layer would be activated and releases carbon dioxide at a higher temperature.

[0048] In order to protect a surface 22 from combustion, the fire suppressant material 10 in some forms is applied and affixed onto the surface 22 to be protected.

[0049] Referring now to FIG. 2, disclosed herein is a fire suppressant material comprising zeolite particles 12 having an internal porous structure 14. Molecules of fire extinguishing substance are contained within the internal porous structure of the zeolite particles 12.

[0050] The fire suppressant material may be provided in the form of a powder consisting of zeolite particles 12 which may further be dispersed in a solvent together with other materials such as polymer in order to be coated on a variety of surfaces. It will be appreciated that the coating should be formulated such that there is a sufficient amount of the binder to retain the fire suppressant material into a contiguous layer, but not cover or envelop the zeolite particles so as to occlude its porosity. Spraying or other suitable techniques may then be employed to form a coating of the fire suppressant material on the desired surface/object. Example of surfaces that can be protected in this manner include walls, roofs, roof tiles, the surface of internal cavities, and vegetation. In another embodiment of the invention, the fire suppressant material may be sprayed or otherwise deposited onto vegetation such as trees, bushes and grass in front of an approaching fire. In another embodiment of the invention, the fire suppressant material may be sprayed or otherwise deposited directly onto a fire.

[0051] Zeolites 12 are microporous, aluminosilicate crystalline minerals widely used as commercial adsorbents and catalysts, which have many different structural forms, and occur both naturally and through manufacturing. The principal raw materials used to manufacture zeolites are silica and alumina, which are among the most common mineral components on earth. Zeolites can confine molecules or ions 16 in small nanopore spaces 14 as shown best in FIG. 2, which causes changes in their structure and reactivity and can give rise to very specific absorption properties. The molecules or ions may be in the form of sodium or potassium or alternative molecules or ions.

[0052] Referring to FIG. 3, an electron micrograph of one embodiment of a fire suppressant material is shown. In this image the fire suppressant material is in the form of selected zeolite particles 18 that have the ability to absorb and store carbon dioxide gas molecules via physisorption into 0.5 nm pores (in 5A zeolite). By carefully selecting the zeolites characteristics (for example composition, structure and porosity), it may be made to absorb a volume of carbon dioxide that may be almost 100 - 200 x greater than the volume of the zeolite itself. The carbon dioxide that is physisorbed (i.e., physically absorbed) in these pores of the zeolite may then be released by the application of heat, which may be transferred from the embers generated from the combustion process. The fire suppressant material of the invention may be tailored in such a way that a temperature of even up to only 80° C. provides heat energy that is sufficient to break the bonds formed between the carbon dioxide and the pore surface and release the molecules of carbon dioxide from the pores.

[0053] The fire suppressant material may also be used in many other applications, such as in roof cavities, car insulation and even for coating combustible tower block claddings and coatings. Faulty wiring, including faulty electrical outlets and malfunctioning appliances, is one of the most common causes of house and apartment fires. Cases of such fires are high in months where there is an increase use of lights and heating appliances. In roof fires, light fixtures and electrical wirings in the attic are usually the culprits. Burned wires can start a fire in houses and they are dangerous because they often go unnoticed. Loose electrical connections are the primary cause of burned wires.

[0054] The fire extinguishing substance of the fire suppressant material of the invention may comprise carbon dioxide, water molecules or any other extinguishing substance. In the case of water, zeolites have the ability to trap water molecules in their internal pores. Water is a cheap and environmentally friendly option to extinguish fires that is readily available, but usually requires more heat to desorb, and this desorption is slower than for CO.sub.2.

[0055] The fire suppressant material of the invention may also have the ability to be regenerated by simply exposing the fire suppressant material to the atmosphere after it has released the entrapped fire extinguishing substance. Carbon dioxide (or water vapor) is freely available in the atmosphere and the zeolites simply need to be exposed to the atmosphere for reabsorption of these gases into the microstructure. Similarly, the fire suppressant material may also be regenerated by exposure to other sources of gaseous carbon dioxide. For example, industrial flue gases generated from the burning of fossil fuels and other similar processes contain significant amounts of carbon dioxide and water vapor. In this sense, the fire suppressant material of the invention can serve to reduce the amount of carbon dioxide released to the atmosphere by burning of fossil fuels.

[0056] In a yet further embodiment, the fire suppressant material of the invention can be employed as an additive that improves the effectiveness of direct fire suppressant systems. For example, partially hydrophobic zeolites containing absorbed carbon dioxide molecules may be used to stabilise an air or carbon dioxide foam for use in direct fire suppression. As the foam becomes heated, the heat activates the carbon dioxide (or water molecules) in the internal pores of the zeolite thus releasing large amounts of carbon dioxide. Such a release will support the action of the foam in fire suppression. A wide range of foams can be produced using different mixtures of surfactant, water soluble polymer, electrolytes and zeolite micro-particles. However, foams can be stabilised using nano- and micro-sized particles alone, if they are suitably hydrophobized. These foams can be stable for long periods of time, with a lifetime of months. These particles could be added to the currently available extinguishing foams and the released CO.sub.2 could improve the effectiveness of the ordinary extinguisher foams because it acts as a gas blanket layer (CO.sub.2 is a heavier gas compared with air). Also, use of a natural and biodegradable foaming agent would ensure an environmentally friendly product.

EXAMPLES

[0057] The present invention will now be described with reference to the following examples which should be considered in all respects as illustrative and non-restrictive.

Example 1

[0058] Zeolite or molecular sieve 5A has been used for the absorption of CO.sub.2 from the atmosphere and from pure CO.sub.2 (i.e. 1 atm) emissions, such as from coal fired power stations. This material has uniform nanometer (0.5 nm) size pores ideally suited for the specific absorption of CO.sub.2 molecules.

[0059] When exposed to a pressure of 1 atm CO.sub.2 these materials absorb up to about 15% their weight with the emission of heat. This amount of CO.sub.2 can be almost completely re-emitted by heating the material even to only modest temperatures, below about 80° C. in the atmosphere. Given that the zeolite has a density of about 0.7 g/mL, this means that under heated conditions the CO.sub.2 emitted can be up to 100 - 200 x the zeolite volume.

[0060] These zeolites are manufactured and produced commercially in a wide range of shapes and sizes as illustrated in FIG. 4.

Example 2

[0061] Generally, thermal conductivity of burnt clay bricks ranges from 0.4 W/mK to 0.7 [W/mK]

[0062] By comparison, the thermal conductivity of zeolite depends on temperature, pressure, adsorbed gases, and the saturation percentage. At a pressure of 1 bar, saturated with CO.sub.2, the zeolite thermal conductivity is typically about 0.145 [W/(mK)].

[0063] This means in average thermal conductivity of zeolite 5A is 2.75 to 4.8 times less than the thermal conductivity of burnt clay bricks.

[0064] These properties suggest that zeolites could be used in roof cavities for fire protection and as suitable insulation material.

Example 3

[0065] The fire suppressant properties of zeolite 5A can be demonstrated using simple laboratory tests. For example, as shown in FIG. 5, zeolite 5A granules were equilibrated with 1 atm CO.sub.2 and then randomly distributed on a piece of burning wood (FIG. 5A), which was rapidly extinguished using zeolite of ⅒.sup.th the weight on the burning wood (FIG. 5B). Similar results are shown in FIGS. 6A and B, in which an ember was immediately extinguished.

Example 4

[0066] In the case of zeolite 5A, the zeolite has a density of around 0.7 g/ml, when cool, and it absorbs about 2.5 g of CO.sub.2 per 100 g of zeolite, since atmospheric CO.sub.2 has a partial pressure of about 0.3 torr. As the zeolite is heated, even to a modest temperature of 75° C., the absorbed CO.sub.2 will be almost completely desorbed. The volume of this released CO.sub.2 will be many times the volume of the zeolite, especially as the local temperature increases further. When heated by a hot ember (e.g., 300° C.), the zeolite would produce up to .sup.~20 x its volume of CO.sub.2.

[0067] In practice this means that a 10 cm layer of roof cavity insulation will produce about a 1-2 m CO.sub.2 layer in response to this heating, suppressing the heat source. In addition, once cooled the layer will re-absorb this amount of CO.sub.2, enabling for further protection.

[0068] Using zeolite 5A, a roof cavity in Northern winters could theoretically absorb 2.5 g of CO.sub.2 per 100 g and this would correspond to a CO.sub.2 layer of .sup.~20 x this volume, or a layer of up to 2 m thick formed around the roof zeolite layer, within a burning roof cavity. Local heating due to embers or an electrical fault will also form this CO.sub.2 region locally. There may be some advantage in mixing zeolite 5A with zeolite 3A granules to maintain low humidity.

[0069] The above analysis is provided by way of example only, and even larger volumes of CO.sub.2 could be produced depending on the selected zeolite and the pressure/temperature conditions.

[0070] Other embodiments of the invention as described herein are defined in the following paragraphs:

[0071] 1. A fire suppressant material for controlling or extinguishing a combustion process, the fire suppressant material comprising: [0072] zeolite particles having an internal porous structure; and, [0073] molecules of a fire extinguishing substance which are contained within the internal porous structure of the zeolite particles.

[0074] 2. A fire suppressant material according to paragraph 1, wherein the molecules of the fire extinguishing substance are either carbon dioxide or water.

[0075] 3. A fire suppressant material according to paragraph 1 or 2, wherein the pore size of the internal porous structure of the zeolite particles is selected to preferentially absorb carbon dioxide over nitrogen or oxygen.

[0076] 4. A fire suppressant material according to any one of the preceding paragraphs, wherein pores of the internal porous structure are substantially consistent in size and shape.

[0077] 5. A fire suppressant material according to any one of the preceding paragraphs, wherein the material is configured or adapted to activate and release the molecules of fire extinguishing substance upon absorption of heat generated in a combustion process.

[0078] 6. A fire suppressant material according to paragraph 5 wherein the activation occurs at a temperature up to 80° C., or up to or around 200° C., or up to or around 300° C.

[0079] 7. A fire suppressant material according to any one of the preceding paragraphs, wherein the material is configured or adapted (such as via storage of the zeolite under conditions to absorb the maximum CO.sub.2, e.g., at 1 atmosphere of CO.sub.2) such that activation upon absorption of heat results in release of a volume of molecules of fire extinguishing substance that is 100 - 200 times greater than the volume of the zeolite particles.

[0080] 8. A fire suppressant material according to any one of the preceding paragraphs, wherein the material is configured to absorb CO.sub.2 from the atmosphere and release this gas when exposed to heat, even up to modest levels of below 80° C.

[0081] 9. A fire suppressant material according to any one of the preceding paragraphs wherein the material is capable of being regenerated on exposure to the atmosphere or an alternative source of the fire extinguishing molecules.

[0082] 10. A fire suppressant material according to paragraph 9, wherein the material is able to absorb the fire extinguishing substance from the atmosphere or the source of the extinguishing molecules.

[0083] 11. A fire suppressant material according to any one of paragraphs 1-10, wherein the zeolite particles comprise zeolite 5A particles and/or zeolite 3A or 4A particles.

[0084] 12. A product for protecting a surface from a combustion process, the product comprising the fire suppressant material of any one of the preceding paragraphs.

[0085] 13. A method for protecting a surface from a combustion process, the method comprising the steps of: [0086] depositing a protective material onto the surface, the protective material comprising zeolite [0087] particles with an internal porous structure having molecules of a fire extinguishing substance [0088] contained in the internal porous structure of the zeolite particles.

[0089] 14. A method for protecting a surface from a combustion process, the method comprising the step of: depositing a fire suppressant material according to any one of paragraphs 1-11 onto the surface.

[0090] 15. A method as defined in paragraph 13 or paragraph 14, wherein the zeolite particles are dispersed in a solvent.

[0091] 16. A method as defined in any one of paragraphs 13-15, wherein the fire suppressant material is designed or adapted to activate and release the extinguishing substance at up to 80° C., or up to 300° C.

[0092] 17. A method as defined in any one of paragraphs 13-16, wherein the fire suppressant material is formulated to suppress ignition of fires or protect against ember attack.

[0093] 18. A method of improving a fire suppressant system comprising the step of: adding the fire suppressant material of any one of paragraphs 1 to 10 to a direct fire suppressant system.

[0094] 19. A method of suppressing a fire comprising the step of: applying the fire suppressant material of any one of paragraphs 1-10 directly to the fire.

[0095] 20. A method of forming a barrier to fire comprising the step of: applying the fire suppressant material of any one of paragraphs 1-10 to the area where a barrier to fire is required.

[0096] Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms in particular features of any one of the various described examples may be provided in any combination in any of the other described examples. Various modifications and alterations to this invention will become apparent to those skilled in the art without departing from the scope and spirit of this invention. It should be understood that this invention is not intended to be unduly limited by the illustrative embodiments and examples set forth herein and that such examples and embodiments are presented by way of example only with the scope of the invention intended to be limited only by the claims set forth herein as follows.