Long-term fire retardant with corrosion inhibitors and methods for making and using same

#Long-term retardants contain retardant salts that alter the way a forest fire burns, decrease the fire intensity, and slow the advance of the forest fire. Long-term retardants may be available as wet or dry concentrates that are mixed with water thereby improving water's effectiveness and ability to cling to fuels, over a long period of time. Long-term retardants may be colored with iron oxide, fugitive pigments, or remain uncolored.

#In the “Ecological Risk Assessment of Wildland Fire-Fighting Chemicals: Long-Term Fire Retardants” (September 2017), hereby incorporated by reference in its entirety, the United States Forest Service (“USFS”) has established a chemical toxicity risk assessment for fire-fighting chemicals currently approved for use by the USFS. The USFS uses a variety of fire-fighting chemicals to aid in the suppression of fire in wildlands. These products can be categorized as long-term retardants, foams, and water enhancers. This chemical toxicity risk assessment of the long-term retardants examines their potential impacts on terrestrial wildlife, plant, and aquatic species.

#Further, in Specification 5100-304d (Jan. 7, 2020), Superseding Specification 5100-304b (July 1999), Superseding Specification 5100-00304a (February 1986), entitled “Specification for Long Term Retardant, Wildland Fire, Aircraft or Ground Application,” hereby incorporated by reference in its entirety, the United States Department of Agriculture (“USDA”) Forest Service has established the maximum allowable corrosion rates for 2024T3 aluminum, 4130 steel, yellow brass and Az-31-B magnesium. The corrosivity of forest fire retardants, in concentrate, to aluminum, steel, yellow brass and magnesium must not exceed 5.0 milli-inches (“mils”) per year as determined by the “Uniform Corrosion” test set forth in Section 4.3.5.1 of the USDA Forest Service Specifications. The Forest Service Specifications identify the maximum amount of corrosion acceptable when both the retardant concentrate and its diluted solutions are exposed to each metal indicated above at temperatures of 70° Fahrenheit (“F”) and 120° F. in both totally and partially immersed configurations. The maximum allowable corrosivity of aerially applied fire-retardant diluted solutions to aluminum is 2.0 mils per year (“mpy”) and the maximum corrosivity to brass and steel is 2.0 mpy when partially immersed and 5.0 when tested in the partially immersed condition. In the partially immersed configurations, one-half of the coupon is within the solution and one-half is exposed to the vapors in the air space over the solution.

#The skilled artisan will understand that the drawings primarily are for illustrative purposes and are not intended to limit the scope of the inventive subject matter described herein. The drawings are not necessarily to scale; in some instances, various aspects of the inventive subject matter disclosed herein may be shown exaggerated or enlarged in the drawings to facilitate an understanding of different features. In the drawings, like reference characters generally refer to like features (e.g., functionally similar and/or structurally similar elements).

#FIG. 1 is a flow chart diagram showing the process of making a forest fire retardant composition.

#FIG. 2 is a graph showing the viscosity over time of Example 1 after blending with 70° F. water.

#In General

#Referring to FIG. 1, a forest fire retardant composition 200 can be provided in various liquid forms. The composition 200 can be provided as a liquid concentrate 201. The composition 200 can also be provided as a final diluted product 202 in a form suitable to fight forest fires via aerial- or ground-based application. The final diluted product 202 is formed by diluting the liquid concentrate 201 with water in one or more diluting steps.

#Components of the Liquid Concentrate