Multi-class fire extinguishing agent

Abstract

A fire extinguishing agent may include a foam and at least one inert gas combined with the foam. A method of extinguishing a fire including a burning metal and/or a burning metal compound and also including a burning plastic material and/or a burning paper material may include combining a foam and at least one inert gas to form a fire extinguishing agent, and applying the fire extinguishing agent to the fire.

Claims

1. A fire extinguishing agent comprising: a foam; and at least one inert gas combined with the foam, wherein the at least one inert gas comprises at least one of helium, neon, argon, krypton, xenon, and radon, and wherein the fire extinguishing agent does not comprise any of the following: an oxidizer, hydrogen gas, nitrogen, carbon dioxide, halomethanes, fluorine, chlorine, and sulfur.

2. The fire extinguishing agent of claim 1, wherein the foam comprises a foam fire extinguishing agent.

3. The fire extinguishing agent of claim 1, wherein the fire extinguishing agent comprises a ratio of foam to inert gas of 60 gallons of foam-generating solution to 400 cubic feet of the inert gas.

4. The fire extinguishing agent of claim 1, wherein the at least one inert gas further comprises a concentration of the at least one inert gas greater than concentrations naturally occurring in air.

5. A fire extinguishing agent comprising: a foam fire extinguishing agent; and at least one inert gas combined with the foam such that the foam traps the inert gas within the foam, wherein the at least one inert gas comprises at least one of helium, neon, argon, krypton, xenon, and radon, and wherein the fire extinguishing agent does not comprise any of the following: an oxidizer, hydrogen gas, nitrogen, carbon dioxide, halomethanes, fluorine, chlorine, and sulfur.

6. The fire extinguishing agent of claim 5, wherein the fire extinguishing agent comprises a ratio of foam to inert gas of 60 gallons of foam-generating solution to 400 cubic feet of the inert gas.

7. The fire extinguishing agent of claim 5, wherein the at least one inert gas further comprises a concentration of the at least one inert gas greater than concentrations naturally occurring in air.

Description

DESCRIPTION OF EXEMPLARY EMBODIMENTS

(1) Reference will now be made in detail to some possible embodiments of the invention, examples of which are outlined in this description.

(2) According to one embodiment, a fire extinguishing agent configured to extinguish a Class D fire and one or more other classes of fires such as, for example, a Class A fire and/or a Class B fire, may include a foam and one or more inert gases combined with the foam. For example, the foam may include a foam marketed by Tyco International Ltd. as ANSUL TARGET-7 foam. The use of other foam agents known to those having skill in the art is contemplated. Some embodiments may include foam agents that do not include foams based on fluorocarbon chemistry, such as, for example, AAAF-type foams. The one or more inert gases may include, for example, helium, neon, argon, krypton, xenon, and/or radon. For example, the fire extinguishing agent may include a conventional fire fighting foam gasified with, for example, helium and/or argon, although neon, krypton, and/or xenon may be included in the fire extinguishing agent.

(3) The foam and the one or more inert gases may be combined via any method known to those having skill in the art, such as, for example, via combining in a nozzle of a fire extinguisher agent delivery apparatus and/or combining in a fire extinguisher agent mixing conduit. The fire extinguishing agent may be applied to a fire via any methods and/or devices known to those having skill in the art. According to some embodiments, the foam and the one or more inert gases may be combined in a ratio corresponding to about 60 gallons of foam-generating solution per 400 cubic feet of inert gas. Other ratios are contemplated.

(4) Most classes of fires, including Class D fires, require fuel, an oxidizer, and heat in order to sustain combustion. Unlike most other classes of fires, however, Class D fires can sustain combustion by liberating necessary oxidizers from otherwise stable compounds, such as, for example, CO.sub.2 and/or Halon. Furthermore, unlike many common classes of fires, metal and/or metal compound fires may burn in oxidizers other than oxygen, such as, for example, chlorine, fluorine, and/or nitrogen. Class D fires, however, cannot burn in an inert atmosphere. The family of true inert or noble gases includes helium, neon, argon, krypton, xenon, and radon. Many of the inert gases may be currently thought to be too rare to be economically viable for use in a fire extinguishing agent. Further, radon is radioactive. As a result, helium and argon are two inert gases that currently appear to be desirable for use in a fire extinguishing agent according to some embodiments.

(5) Attempting to extinguish fires including burning metal(s) and/or metal compound(s) (e.g., Class D fires) using one or more inert gases alone, however, may be very difficult. For example, attempting to use an inert gas alone to deprive such a fire of its oxidizer may not be effective because maintaining coverage may be difficult since helium is lighter than the surrounding atmosphere and will quickly float off, and argon is heavier than the surrounding air and will tend settle away from the area of deployment. Furthermore, the use of conventional foams to extinguish burning metal(s) and/or metal compound(s) has proven substantially ineffective, for example, because the water in the foam reacts with the metals to liberate hydrogen and because of the extreme heat of Class D fires, the fire's reaction will continue and use the air and/or nitrogen in the foam as an oxidizer, and the fire will continue to burn.

(6) The combination of foam and inert gas may be effective because when water in the foam reacts with the metal, a hydroxide radical (not oxygen or any other oxidizer) is liberated during the reaction. Hydrogen is also liberated, but in the absence of an oxidizer (no air or nitrogen is used to generate the foam), the fire is starved out. The foam may serve to trap the inert gas and keep it positioned where it most effectively acts to extinguish the fire.

(7) Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.