JP2008517635A - An improved method for extinguishing flammable liquid fires in industrial storage tanks. - Google Patents

Abstract

A system and apparatus for extinguishing a difficult-to-extinguish fire, the system and apparatus for extinguishing a fuel or flammable liquid fire in a storage tank equipped with at least an effective fixed upper roof, According to the system, a fire extinguishing agent is released in a timely manner into a fairly enclosed space or cavity defined between the fuel / liquid surface or any floater above it and the fixed upper roof, Facilitates such a system.
[Selection] Figure 9

Description

  The present invention relates to an improved system for extinguishing flammable liquid fires in industrial scale storage tanks having a roof that is generally a fixed roof above the tank and providing a space above the liquid, and in particular a powder fire extinguisher. Relates to a method and apparatus incorporating the use of.

  Industrial fuel and / or flammable liquid storage tanks often have a roof that provides space above the liquid, which is typically a conical or geodesic roof welded to the top of the tank. Such tanks may have a double roof that includes an internal floating roof called a floater, and the floater is designed to have a seal that floats on top of the fuel / liquid and provides a seal against the inside of the tank wall. Is done. Fixed conical or geodesic top roofs are generally attached by welding. A roof system that includes a single fixed top, or two parts of a fixed top and a floater, creates and defines a space or cavity between the lower fuel / liquid surface and / or the floater and the upper roof. .

  Fires in industrial storage tanks with sealed and fixed roofs pose unique challenges. Industrial storage tanks are tanks with a diameter of 60 feet or more. The height of the tank wall is typically 50 feet and is usually more than 45 feet. The upper part of the tank wall just below the periphery is usually characterized by a series of eyebrow vents surrounding it. The eyebrow vent has an action such that vapor does not condense in the tank and escapes from the tank. When steam condenses in the tank, various dangers arise. Thus, vents are usually provided to release vapors that condense into the space or cavity between the fuel / liquid (or floater) and the upper fixed roof into the atmosphere. A common vent is the “brow vent”, a rectangular opening placed around the upper part of the vertical tank wall, a scooper vent at the top of the tank and / or around the upper roof Including a roof vent with an opening disposed around the space.

  If the vapor from the liquid inside the tank, such as gasoline or crude oil, is lit, the roof is generally not blown away. Fire occurs mainly at a series of vents located leeward. (Air is sucked in through the vent on the windward side.) The liquid in the tank is vaporized, but in the space above the liquid level and below the fixed roof, there is generally sufficient oxygen to maintain complete combustion. I can't get it. (It is possible that the mixed steam in the cavity partially burns in the cavity.) However, when the steam exits the vent and contacts oxygen in the atmosphere, complete ignition and complete combustion occurs.

  Industry standards procedures for extinguishing (or at least trying to) fire extinguishing with activities using foam are prescribed by NFPA in the event of a fire in a fuel or flammable liquid tank with a fixed top roof Yes. This fire fighting activity typically involves covering the fuel / liquid surface with a foam fire extinguishing layer by releasing foam extinguishant into the space or cavity between the fixed upper roof and the liquid level and / or floater. is there. As noted above, complete combustion is generally only at the vent where fuel / liquid vapors come into contact with air in the atmosphere, and only at the lee vent while sucking air into the cavity with the upwind vent. Occur.

  NFPA adjusted for different types of fuels or flammable liquids to achieve fire extinguishing, using various foam extinguishing agents and foam addition rates adjusted for different tanks, foam extinguishing agents Have guidelines on the duration of fire fighting.

  It has been found that after applying an adequate and sufficient foam layer according to regulatory standards, a fire may remain in a covered tank situation. Observation shows that considerable vapor is still trapped in the space above the foam extinguisher layer and below the fixed roof, and a certain amount of rich incomplete combustion above the foam layer in the enclosed space. Has been shown to be possible. Furthermore, since the 25% discharge time of foam is 2-8 minutes, the foam layer is not permanent. Sooner or later, the foam extinguisher layer will allow steam to pass through, and steam will be replenished into the space above the foam extinguisher layer. If the cavity above the liquid level and below the fixed roof is quite large, the burning time of only the steam confined in the space can be long without refilling and can be several hours. This is an unacceptably long time, even if a suitable foam layer prevents the passage of further vapors. The supply of foam extinguishing agent is limited, and fire extinguishing within a predetermined time is required.

  According to experience in extinguishing a mixed fuel tank fire in Guatemala, even if foam extinguishers were placed in the cavity in compliance with the procedures, ratios and times recommended by NFPA, It was shown that it may not be possible to extinguish difficult-to-extinguish fuel or flammable liquid fires with foam extinguishing agents alone. Worryingly, this is likely to be the case for new blended fuels with high octane content, and is an uneasy discovery. Foam extinguishers alone may not be extinguished at all and do not completely comply with current NFPA regulations or guidelines. Furthermore, the inventor of the present invention has experience in which steam passes through the foam extinguisher layer or a foam foam of the foam is formed. Bubbles gradually flow out of the vent and fall to the ground while burning.

  In addition, any flammable liquid, including crude oil, creates vapor in the cavity above the liquid level and in the cavity below the roof (and at least in certain vents, if not in the cavity), thereby creating a fire extinguisher. It was confirmed that the fire continued to burn for a considerable time after the formulation was established. This fire may persist after an appropriate foam extinguisher layer is established by NFPA. If the tank level is low enough and / or the cavity is large enough, the fire from the cavity steam can persist for several hours after a suitable foam layer is established. Within this time, the foam is dry out, allowing steam to pass through the foam layer and refilling the cavity with steam. The supply of foam may not be sufficient to maintain a sufficiently fresh foam layer over several hours.

  Thus, according to the present invention, not only fires that are difficult to extinguish in a fixed roof or a tank with a roof that creates a space between the roof and liquid, but also fires of any flammable liquid are cost-effectively extinguished. An improved system designed to do is taught. This improved system is designed to cost-effectively extinguish not only flammable liquid fires but also difficult-to-extinguish fires of high octane content fuels and flammable liquids. In accordance with the present invention, it is taught to release a powder fire extinguisher in a stepwise and timed manner into the space between the burning fuel / liquid and the roof. The timing of the powder extinguishing agent release phase is selected after the foam extinguishing agent has been added for an appropriate time. Powder extinguishers are a limited and limited amount of resources. If the powder fire extinguishing agent is released too quickly, it may not be effective and therefore waste resources.

  The release of powder extinguishing agent can be performed using one of several means or techniques using portable and / or fixed systems. ("Fixed systems" are equipment that was installed before the fire and were fixed in anticipation of an emergency before an emergency. In contrast, a portable system detects an emergency. If so, bring it to the place.) A vent provided to release vapor condensing under the roof, in the space above the fuel / liquid and under the roof Preferably, it is used as an inlet means for releasing. Whether it is a portable system or a fixed system, existing vents could be used. Alternatively, a special port for a fixed foam fire extinguisher system can be utilized for a fixed powder fire extinguisher system. Similarly, a special port for a fixed powder fire extinguisher system can be formed.

  After a fire extinguishing action with sufficient foam extinguishing agent, insert a powder fire extinguishing agent in the space between the burning fuel / liquid and the roof in a timely manner, so that a persistent harmful fire remaining in the cavity or It is the inventor's experience and observation that it is useful for pursuing a flame whose direction is not fixed and extinguishing it completely. As described above, the movement of air into the cavity through the windward vent or opening helps the fired fire extinguisher to follow the flame. In the case of foam extinguishing agent alone, it may not be a good and more expensive way to completely extinguish such residual flames in a tank, if not an inappropriate measure. It is. In addition, foam extinguishers are expensive. If extra time is taken to ensure that the fire extinguisher is extinguished, even if the fire extinguishing can be achieved by the continuous addition of only the foam, it is unnecessarily expensive compared to the present invention. End up.

  The so-called staged powder fire extinguisher method and apparatus for extinguishing a (fixed roof) tank fire can be implemented in a variety of forms, including the use of portable devices and / or fixed systems. . Fixing systems and / or special portable devices may be less dangerous for firefighters, as firefighters climb up the tank and walk on the roof, existing or formed vents, or appropriate It appears to be preferred over a portable embodiment in which the powder extinguishing agent has to be inserted through the opening by a handheld nozzle.

  As used herein, the term “difficult fuel or flammable liquid” or “difficult fuel or flammable liquid fire” means at least essentially a low surface tension fuel / liquid and / or high vapor pressure. Refers to fluid fuel or flammable liquid that is fuel / liquid and / or octane boosted fuel / liquid and / or oxygenated fuel / liquid. One skilled in the art will appreciate that what is implicitly compared to these examples is a linear fuel or flammable liquid that is important in the history of the mid-20th century.

  However, it has been found that the present invention applies quite well to linear fuels or flammable liquids that are important in the history of the mid-20th century.

  It should be noted that the tank is designed to have a specific roof system and may originally exist as such, but some or all of the original roof system will change due to a fire or disaster. Or may be destroyed. Therefore, it may be necessary to re-evaluate the characteristics of the storage tank. The original floating roof or floating roof portion may be inclined or partially depressed or totally depressed. The seal part may be destroyed in whole or in part. The fixed roof may be blown away, distorted, partially disengaged or tilted, or at least a connection location such as a welded connection with the tank wall may be partially or totally destroyed. The present invention relates to a tank that still has at least a fairly large roof that creates a substantially sealed space above the fuel / liquid and below the roof in the event of a fire.

  That is, the present invention is burning a fuel or flammable liquid that is difficult to extinguish, with at least a fairly large roof above the fuel / liquid surface and defining a substantially sealed space or cavity therebetween. Related to the situation. Welds may be blown off from the original fixed roof, and the hatch and vent may be blown separately, but there is significant space or cavities remaining between the burning fuel / liquid and the roof. If so, the present invention is applied. Again, the fuel / liquid may be burning only where sufficient oxygen is secured at the opening, such as a vent, where the fuel vapor meets the atmosphere. Partial combustion may have occurred in the cavity.

The present invention discloses a system for extinguishing a fire of a flammable liquid containing a fuel that is difficult to extinguish, at least in a storage tank having a roof, with a roof above a substantial portion of the liquid and below the roof. A substantially closed space is formed by the portion, and a fixed roof portion substantially remaining in a predetermined position is attached to the normal tank. The present invention involves creating a layer of foam on the fuel / liquid surface, such as by releasing the foam into a cavity above the fuel / liquid. (A foam extinguisher layer should be understood to include a foam and / or a film.)
Preferably, after covering at least 90% of the liquid surface with a foam layer and / or making at least a minimal foam layer under such circumstances, a considerable amount of time under such circumstances, etc. After establishing a foam layer, most preferably after performing at least two-thirds of the NFPA recommended rate / time procedure guidelines for fire fighting with foam, Discharge powder extinguisher into the cavity above and below the roof. Preferably, the powder extinguishant is released within the last 10 minutes of the NFPA recommended rate / time procedure guidelines for fire fighting with foam. Powder extinguishers are generally released for 10 to 30 seconds.

  Existing steam vents provide an unexpected opening to discharge powder extinguishant into the cavity between the fuel / liquid and the roof using a portable or fixed powder extinguisher system. Preferably, the powder extinguishing system is already in place, having a conduit and nozzle connected to a powdered fire extinguishing source, such as a wheeled device or powder extinguishing skid, with the discharge orifice or nozzle in the cavity. Arrange it.

  A suitable portable system preferably comprises a powder extinguisher wand attached to a T-shaped or cellar discharge nozzle. The wand can be suspended with a nozzle that is inserted through a suitable opening and / or vent. If the roof is a “fish mouth” type separated from the wall, an appropriate opening is obtained. In that case, the firefighters can retreat a safe distance to avoid injury to personnel resulting from flashbacks and / or roof explosions.

  Fixing devices for extinguishing flammable liquid fires containing fuel that is difficult to extinguish in a storage tank having a cavity between the fuel / liquid surface and the roof rise along a part of the tank wall, e.g. At least one end opening into the tank vent or port through a roof vent or eyebrow vent, through a fixed foam system that opens into the tank, or through a fixed powder extinguisher port At least one powder fire extinguishing supply pipe or line. This supply pipe is arranged in circulation with a wheeled device having a supply source of dry powder, a skid or the like. The supply pipe is preferably always attached, but may be portable. The powder fire-extinguishing agent discharge nozzle in the cavity is preferably in circulation with the supply pipe.

  A better understanding of the present invention can be obtained by considering the following detailed description of the preferred embodiments with reference to the drawings, in which: The drawings are exemplary in nature. It should be understood that the structure may be simplified or omitted in detail to convey particular aspects of the invention. The scale may not be true for clarity.

  FIG. 1 shows a tank T having what is called a composite roof system. The system includes a floating roof or floater FR and a fixed roof FXR. A space or cavity C is formed between the floating roof portion FR and the fixed roof portion FXR. It should be understood that the floating roof portion FR floats above the fuel / liquid F in the tank T. It should be noted that a space or cavity C would be formed above the fuel / liquid surface and below the fixed upper roof portion even without a floater or substantially no floater remaining in the event of a fire. I want you to understand.

  In the worst case scenario, fuel / liquid F is a mixed fuel. The mixed fuel may have a high octane content, leading to a situation where it is difficult to extinguish. The fuel / liquid F is at least a combustible liquid and may be any fuel / liquid that is difficult to extinguish.

  The tank T of FIG. 1 further shows a fixed or portable system portion for adding powder extinguishant and includes an annular pipe extension PE having a pipe extension leg with a T-shaped end PEN. FIG. 4 shows in more detail a pipe extension PE having a T-shaped end PEN. The T-shaped end portion is inserted into the eyebrow-shaped vent EV of the tank T to discharge the powder fire extinguisher into the inside, and the powder fire extinguisher is discharged to the inside of the tank side plate in the cavity C. Is done.

  In a general embodiment, the fixed roof portion FXR is a conical roof fixed to the top of the tank wall. Geodesic fixed upper roofs are also known. The floating roof portion FR floats up and down together with the surface of the fuel / liquid remaining in the tank T, and includes a seal portion for sealing the inner tank wall. Of course, there may be no floating roof, or there may be depressions in whole or in part.

  FIG. 2 is a top view of a conical roof FXR having a series of roof vents RV and a roof vent cover CRV. FIG. 2 further illustrates that the fixing or carrying system for adding the powder extinguishing agent comprises an upper extension TE that extends upward and onto the conical roof FXR. In the embodiment of FIG. 2, the pipe or line extension PE encircles the conical roof FXR near the vent RV. A part of the pipe or line extension PE extends toward the vent RV, and the powder fire extinguisher can be discharged through the vent into the cavity C in the tank.

  FIG. 3 is a view showing a part of a powder fire extinguisher (fixed or portable) system including a riser pipe or a supply pipe P. The tank preferably comprises a fixed riser pipe for adding powder extinguishing agent. However, a non-fixed portable powder fire extinguisher riser pipe P or line can also be used. In simple cases, the pipe extension and the pipe end may simply be the end of the straight riser pipe P. It would be possible to insert or push one end of such a straight powder fire extinguisher pipe into the eyebrow vent during a fire.

  In the absence of a fixed system for the addition of powder extinguishers that provides pre-installed parts such as riser pipes, pipe extensions, pipe ends and / or nozzles, a portable nozzle attached to the supply line may be used. Can be used by firefighters to implement this method. However, in such a case, a firefighter needs to approach (or form) a suitable vent or opening on the tank or roof in order to insert the powder extinguisher through the vent or opening. there will be.

  When using a portable system, suspending the powder extinguisher nozzle on the end of the wand through an appropriate opening is necessary to hold the handheld powder extinguisher nozzle by hand. It is clearly preferable in comparison. There is a clear possibility that the steam will flash back and the roof will blow away from the tank.

  A method of extinguishing a flammable liquid fire in a tank with a fixed roof, including fires that are difficult to extinguish, includes a fire extinguishing activity with an initial foam extinguisher, creating a foam extinguisher layer. (Again, the foam contains a film.) The foam is inserted into the cavity between the floating bottom roof and / or the fuel / liquid surface and the top roof. It is preferred to establish and form a layer. The foam must be inserted or placed in the cavity until the fuel / liquid surface is substantially covered and substantially free of fire. A fire extinguisher has been virtually eliminated in most cases with a layer of foam on the surface of the fuel / liquid and / or floating roof in accordance with current NFPA guidelines for foam, fuel / liquid and tanks. It can be determined that this is the case. The time required for this will vary depending on the type of foam used, the ability to release the foam, the size and complexity of the tank, and the nature of the fuel / liquid contained. Forty-five minutes is a typical example of a generally accepted time for initiating and sustaining fire extinguishing with a foam in the cavity between the floating and upper roofs.

  In a preferred embodiment, at some point during the last 10 minutes in any such foam extinguishing activity, powder into the cavity via one or more vents or other available tank openings Insert fire extinguishing media. If safer or more remotely operable means are not available, firefighters carry handheld nozzles attached to powder extinguishant lines and sources to appropriate openings into the cavity. It is possible to carry out fire extinguishing activities with powder extinguishing agents. The firefighter preferably hangs the wand and powder extinguishing agent nozzle through a possible vent, fish mouth or opening and then retracts to a safer distance. By adding a powder fire extinguisher for 10 seconds, it is possible to considerably expect extinction of the embers and extinguishing of the remaining flames without determining the direction related to the flammable liquid fire, particularly the new mixed fuel.

  According to the inventor's experience of the present invention, in the above situation increased by ventilation in the cavity, by inserting a powder fire extinguisher in such a cavity in time, the remaining fire in the cavity is " "Pursuit" seems to be extinguished. Without such a powder extinguisher treatment, it may be necessary to extend the duration of the foam extinguisher layer to 2 or 3 times the currently set time, which is quite unexpected. This leads to expenses. In fact, there is no guarantee or definitive experience to show that it is possible to extinguish a difficult-to-extinguish flammable liquid fire in a tank under a fixed roof with only foam extinguishers. The provision of foam may not be sufficient to maintain the necessary foam layer for the time required to end the combustion of the vapor in the cavity.

In addition, it is recommended to cool the tank wall and roof above the liquid level with water mist before adding the powder. It is thought that a powder fire extinguisher mainly extinguishes fire by interrupting a series of oxidation treatments. (Powder extinguishing agents also produce a certain amount of CO ₂ that suppresses fire.) For fire to recur in steam, threshold levels of heat and oxygen are required. The foam extinguisher layer removes not only the tank walls but also the liquid heat. Cooling the tank walls and the roof further draws heat. Access to oxygen is limited within the cavity to available openings, mainly or generally eyebrow vents. (Of course, other openings may have been formed by fire, such as hatches being blown and / or seals broken, etc.) Proper cooling effect is obtained and this is the approach to oxygen access. If increased by the limit, it can be extinguished to prevent recurrence by adding dry powder at the appropriate time.

  Powder fire extinguishers are a relatively rare item in a fire. Powders should be carefully distributed for use. Limiting the supply of powder extinguishers makes it substantially impossible or impossible to release powder extinguishers, even for a few minutes. Therefore, if a powder extinguisher should be used, it must be used carefully. Compared to water and / or foam extinguishing resources, the potential for use in almost every environment should be considered rather limited. Therefore, it is not desirable to start fire extinguishing with a powder fire extinguisher until at least two thirds of the time with the standard recommended NFPA foam extinguishing fire as per the NFPA guidelines has elapsed.

  For example, if fire extinguishing with a foam lasts for 55 to 60 minutes, fire extinguishing with a powder should not be started until approximately the last 20 minutes, preferably until the last 10 minutes. . In the absence of procedural guidelines for specific foam extinguishers or tanks or fire addition rates / time recommended by NFPA for a given environment, the scene based on existing NFPA recommendations in the most relevant environment It is necessary that the firefighters presume appropriate guidelines for the NFPA guidelines in this case.

  FIG. 5A shows a preferred embodiment for a tank T having a fixed roof FXR and an integrated fastening system for use in adding foam and powder fire extinguishers. This preferred integrated fastening system for use in adding foam and powder extinguishers comprises a foam expansion chamber FC-HC and associated conduits and valves attached to the tank, the device comprising a powder fire extinguisher. Has been modified to provide drug function. The illustrated chamber FC-HC is attached to a level above the wall of the tank T and communicates with the inside of the tank through the opening O. In this embodiment, the illustrated bubble chamber FC-HC itself has an opening O or port inside the tank T and cavity C. The fixed pipe P transmits the powder fire extinguisher from a general mobile or portable powder fire extinguisher supply system. The mobile or portable powder fire extinguisher supply system is, for example, a powder fire extinguisher wheeled device DCWV or a general powder fire extinguisher skid DCS brought in an emergency. The powdered fire extinguisher wheeled device generally flows into the powder extinguisher collection manifold CM and then through the line to the stationary pipe P. The fixed pipe P carries the powder extinguisher to the discharge orifice or nozzle inside the tank through the bubble expansion chamber FC-HC and the opening O. By combining the fixed pipe P and the foam chamber, both of these fixed systems can be operated through a single tank opening or port.

  FIG. 5B shows a preferred embodiment for a tank T having a fixed roof FXR and a stand-alone fixing system for adding a powder fire extinguisher. This preferred stand-alone fastening system used when adding powder extinguishers is derived from a powder extinguisher source such as a typical powder extinguisher wheeled device DCWV or a typical powder extinguishing skid DCS. And / or a line PL. This pipe and / or line combination is partly fixed to the tank but led to an opening O in the upper part of the tank wall. It is preferable that the powder extinguisher nozzle PEN is attached to the inside of the tank wall, is fitted in the opening O, and is in circulation with the pipe and / or the line system PL.

  6 and 7 show a side view and a plan view of a bubble expansion chamber FC-HC having a powder extinguisher function and associated conduit valves. The foam expansion chamber includes a chamber for expanding and reducing the speed of the foam extinguishing agent stock solution before discharging through the opening O on the side wall of the tank T. The foam extinguisher system is supplied with a fire extinguishing fluid containing liquid water and a foam extinguisher stock solution via a fluid pipe FP. These water and foam stock solutions pass through an orifice plate OP having small holes or orifices where a pressure difference is created. The orifice plate OP has a handle H that resembles a spatula. Due to the pressure difference that occurs in the line FP beyond the orifice plate OP, air is sucked through the vent AV illustrated as a mushroom vent with a screen. In this embodiment, a check valve V as a steam seal is shown in the line. With sufficient pressure from water, foam extinguisher stock solution and air, the steam seal is opened and fluid is sent into the foam chamber FC. Before being discharged into the inside of the tank T through the opening O, the foam is further expanded in the bubble chamber FC, and the speed is reduced. The bubble chamber FC is illustrated with an inspection cover or hatch CV, but these are particularly important for steam seal inspection.

  With regard to the relevant fixing system for the addition of powder extinguishing agent, the powder extinguishing agent is fed from the source through pipe P, through its own check valve, steam seal V, and then through opening O. Reach the tip for discharging powder. Steam seals or check valves may have different designs and place them in different locations. 6 and 7 further show a high outflow rate release tip HFT and a low outflow rate release tip LFT. With the discharge tip, the powder extinguisher is preferably discharged in three directions: left, right and towards the center by adjustment. The chip may be discharged in only one direction, and in that case, it is preferable to discharge toward the center by adjustment. The discharge tip is preferably adjustable at the time of installation in the expected preferred flow rate and direction taking into account the size of the tank. For example, the discharge tip can be adjusted to generally release approximately 70 pounds per second, 30 pounds per second to the left, 30 pounds per second to the right, and 10 pounds per second toward the central region.

  FIG. 8A shows a wand W that can be used in the portable system for adding a powder extinguisher of the present invention. The wand W is composed of a 11/2 inch pipe with a suitable L-joint, and its end is preferably terminated with a powder extinguisher nozzle PEN. Although FIG. 8A shows a T-shaped powder extinguisher nozzle, a cellar nozzle could also be used for the powder extinguisher at the end of the wand. Cellar type nozzles are well known in the industry. FIG. 8A shows how the wand W is connected to the hose H and utilizes a 11/2 inch hose connector. The hose H is a 1 1/2 inch powder fire extinguisher hose and is connected to a powder fire extinguisher supply source such as a skid supply source DCS. FIG. 8B shows a commercially available (ANSUL) powder fire extinguisher skid source DCS. This powder fire extinguisher skid is both a stationary powder extinguisher supply source and a portable powder extinguisher supply source.

  FIG. 9 is a diagram showing the tank T having the fixed roof FXR and the floating roof FLR in more detail, although the scale is not limited to this. A floating roof is on the top of the fluid F, and a cavity C is formed above the floating roof and below the fixed roof. FIG. 9 shows various sources of steam exiting fluid F into cavity C. The steam can flow out through a general well pipe WP fixed in the tank. Alternatively, the steam can flow out through a ladder connection in the tank. FIG. 9 shows that even if the floating roof FLR is covered by the foam layer, there remains a means for vapor to condense in the cavity C from the fluid F below the floating roof FLR.

  The foregoing descriptions of preferred embodiments of the present invention have been presented for purposes of illustration and description, and are intended to be exhaustive or to limit the invention to precise forms or embodiments disclosed. It was n’t. The description was chosen to best explain the principles of the invention and its practical application so that those skilled in the art may make better use of the invention in various embodiments. Various changes are anticipated to be optimal for a particular application. The scope of the invention is not limited by the description, but is defined by the appended claims. The foregoing disclosure and description of the invention are exemplary and explanatory and the size, shape, material, and details of the illustrated apparatus may vary without departing from the spirit of the invention. It can be changed. When a single element is described, one or more elements are covered, and when two elements are described, two or more elements are covered. To charge. Further, the drawings and explanatory drawings in this specification are not necessarily drawn to scale.

It is a figure which shows a tank provided with a fixed upper roof and a floater, and a space or a cavity is formed between an upper roof and a floater. It should be understood that even without a floater, there is a cavity or cavity between the liquid surface and the fixed upper roof. It is a top view of the upper roof fixed on the tank. On the roof, a vent and a part of the powder extinguishing agent supply system are shown. It is a figure which shows the powder fire extinguisher riser pipe for tanks which has a fixed roof. It is a figure which shows one embodiment of the powder fire extinguishing agent discharge | release head for tank side board inside insertion, and it is preferable for the insertion into a vent hole inside. FIG. 2 shows a tank with a fixed roof, showing a tank with an integrated fixed foam / powder extinguisher system. FIG. 2 shows a tank with a fixed roof, showing a tank with an integral fixed powder fire extinguisher system. It is a figure which shows the integrated fixed foam fire extinguisher and powder fire extinguisher system shown in FIG. 5A in detail. It is a figure which shows the integrated fixed foam fire extinguisher and powder fire extinguisher system shown in FIG. 5A in detail. It is a figure which shows the wand for suitable portable powder fire extinguishing agents provided with the T-shaped nozzle. It is a figure which shows a commercially available large-sized powder fire extinguisher supply source. FIG. 2 shows in more detail a tank with a fixed and floating roof and a steam supply in a cavity.

Claims (35)

A system for handling a flammable liquid fire on a tank, the tank comprising a roof and a substantially sealed space above the liquid in the tank and below the roof;
Establishing a foam / film layer covering at least 90% of the liquid surface in the tank;
A system for discharging dry powder into a space between the roof and the layer.   The method of claim 1, wherein the releasing step is performed after establishing at least two-thirds of the foam / film layer defined by NFPA.   The method of claim 1, wherein the release occurs within the last 10 minutes of the NFPA defined foam extinguishing time.   The method of claim 1, comprising cooling the tank and / or roof wall above the liquid level with water mist prior to the discharge. An industrial scale fire extinguishing system comprising a tank having a roof, the tank comprising a space above the flammable liquid in the tank and substantially sealed below the roof;
An opening in at least one of the tanks communicating with the space;
Means for forming a foam / film layer on the liquid with respect to the tank;
Means for releasing a powder fire extinguisher into the space with respect to the at least one opening. A fixed foam / powder extinguisher system for an industrial scale tank with a roof,
The tank has a space above the flammable liquid in the tank and below the roof,
At least one foam extinguishing agent conduit fixed to the tank and in circulation with the inside of the tank using a valve;
At least one powder extinguishing agent conduit fixed to the tank, attached to a source of powder extinguishing agent, and configured to circulate with the space under the roof of the tank and a valve. System.   The apparatus according to claim 6, further comprising a nozzle for discharging a powder extinguisher attached to the powder extinguisher conduit. A system for extinguishing a flammable liquid fire in a storage tank fitted with at least an effective fixed upper roof,
Release foam extinguishing agent into the cavity above the fuel / liquid and below the fixed roof;
After performing at least two-thirds of the NFPA recommended rate / time procedure guidelines for fire fighting with the foam, in the cavity above the fuel / liquid and below the fixed roof, A system characterized by releasing a powder extinguisher.   9. The system of claim 8, wherein the fire extinguishing agent is released within the last 10 minutes of the NFPA recommended rate / hour procedure guidelines.   9. A system according to claim 8, which releases the powder fire extinguishing agent for 5 to 15 seconds.   9. The system of claim 8, wherein the fire extinguishing agent is released after the foam is added for at least 40 minutes.   9. The system of claim 8, wherein the fire extinguishing agent is discharged through at least one tank vent.   The system of claim 12, wherein the vent is an eyebrow vent.   13. The system of claim 12, wherein the vent is a stationary system foam and / or powder extinguisher vent.   9. A floater on top of the fuel / liquid, wherein the foam and powder fire extinguishing agent release is into a cavity defined between the floater and the fixed upper roof. System.   The system of claim 8, wherein the flammable liquid comprises a mixed fuel. A device for extinguishing a flammable liquid fire in a storage tank with a fixed roof, comprising at least one vent opening into a space defined by the fuel / liquid surface above and the fixed roof ,
A storage tank comprising a fixed roof, defining a space or cavity above the fuel / liquid surface and below the fixed roof, and containing a flammable liquid;
An apparatus comprising: a powder extinguisher supply pipe system having at least one end opening to an opening of the tank and rising along a portion of the tank wall and in communication with a dry powder supply source.   The apparatus of claim 17, wherein the supply pipe system comprises a wand.   The apparatus of claim 18, wherein the wand comprises a T-shaped discharge nozzle.   The apparatus of claim 18, wherein the wand comprises a color-type discharge nozzle.   The apparatus of claim 17, wherein at least a portion of the supply pipe system is permanently attached to the tank.   The apparatus of claim 18, wherein at least a portion of the supply pipe system is coupled to a fixed foam system.   18. The apparatus of claim 17, comprising a floater, wherein the space defined above the fuel / liquid surface is a space defined above the floater.   The apparatus of claim 17, wherein the combustible liquid comprises a mixed fuel. A fixed powder fire extinguisher system,
An industrial storage tank including a roof and at least one opening;
A powder fire extinguisher supply source disposed outside the tank;
Piping / lines in circulation with the source;
A powder fire extinguishing agent discharge orifice in circulation with the pipe / line,
The powder fire extinguishing agent discharge orifice is disposed inside the tank and configured to pass powder fire extinguishing agent from the source through the piping / line and the opening of the tank to the discharge orifice. A system characterized by   26. The system of claim 25, wherein the discharge orifice comprises a low efflux powder extinguisher discharge tip.   27. A system according to claim 25 or 26, wherein the discharge orifice comprises at least one high flow rate powder fire extinguishing agent discharge tip.   28. The system of claim 27, wherein the high spill rate powder extinguishing agent discharge tip comprises a pair of tips that discharge to the left and right of the tank opening.   28. The system of claim 27, wherein the low spill rate powder fire extinguishing agent release tip releases toward approximately the center of the tank interior.   26. The system of claim 25, wherein the pipe / line is attached to a joint that couples to an opening in the tank.   26. The system of claim 25, wherein the piping / line is integrated within a fixed foam fire extinguisher system, wherein the fixed foam fire extinguisher system is configured to release foam extinguisher through an opening in the tank. A method of extinguishing a fire in an industrial tank having a roof,
Cover the liquid surface in the tank with a layer of foam,
After establishing a foam layer on the liquid in the tank, the powder is passed through an opening opened in at least one of the tank and the roof in a space below the roof and above the foam layer. A method characterized by releasing a fire extinguishing agent.   33. The method of claim 32, wherein the release of the powder fire extinguisher utilizes a fixed powder fire extinguisher system.   34. A method according to claim 32 or 33, wherein the formation of the foam layer is a fixed foam system.   33. A method according to claim 32 comprising water cooling of the tank wall and / or roof surface.

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