Fluorine-free firefighting foams containing one or more biopolymers

1 . A fire-fighting foam composition for fighting a Class B fire, the composition comprising:

a plurality of biopolymers comprising diutan gum, guar gum, and xanthan gum, wherein the combined proportion of the plurality of biopolymers is from about 2 wt % to about 2.5 wt % of the composition;

an anionic surfactant, wherein the anionic surfactant is selected from the group consisting of alkyl sulfates, alkyl ether sulfates, sulfosuccinates and combinations thereof; and

an organic solvent, wherein the organic solvent is selected from the group consisting of glycols, alcohols, glycol ethers and combinations thereof; wherein:

the weight ratio of the anionic surfactant to the plurality of biopolymers is from about 7:1 to about 11:1;

the weight ratio of the plurality of biopolymers to organic solvent is from about 1:1 to about 1:12, and

the composition is free of fluorinated surfactants and fluorine-containing polymers.

2 . The composition of claim 1 , wherein the anionic surfactant comprises an alkyl ether sulfate selected from the group consisting of sodium laureth sulfate, sodium C 8 -C 14 ammonium laureth sulfate, and combinations thereof.

3 . The composition of claim 1 , wherein the anionic surfactant is selected from the group consisting of sodium dioctyl sulfosuccinate, sodium bistridecyl sulfosuccinate, disodium ethoxylated alcohol half ester of sulfosuccinic acid, C 8 -C 16 disodium laureth sulfosuccinate, and combinations thereof.

4 . The composition of claim 1 , wherein the anionic surfactant is selected from the group consisting of sodium laureth sulfate, sodium C 8 -C 14 ammonium laureth sulfate, sodium dioctyl sulfosuccinate, sodium bistridecyl sulfosuccinate, disodium ethoxylated alcohol half ester of sulfosuccinic acid, C 8 -C 16 disodium laureth sulfosuccinate, and combinations thereof; the composition further comprising:

one or more additional components selected from the group consisting of stabilizers, viscosity modifiers, and film formers.

5 . The composition of claim 1 , wherein the organic solvent is present in a proportion of from about 10 wt % to about 25 wt % of the composition.

6 . The composition of claim 1 , wherein the organic solvent is selected from alkyl glycols, glycol ethers, and combinations thereof.

7 . The composition of claim 6 , wherein the organic solvent is present in a proportion of from about 10 wt % to about 25 wt % of the composition.

8 . The composition of claim 6 , wherein the organic solvent is present in a proportion of from about 10 wt. % to about 20 wt. % of the composition.

9 . The composition of claim 1 , the composition further comprising water.

10 . The composition of claim 9 , wherein water constitutes from about 30 wt % to about 65 wt % of the composition.

11 . The composition of claim 1 , the composition further comprising a stabilizer, viscosity modifier, and/or film former.

12 . The composition of claim 1 , the composition further comprising a zwitterionic surfactant selected from sultaines and betaines.

13 . The composition of claim 1 , wherein the composition further comprises an inorganic bridging ligand as a viscosity modifier selected from magnesium sulfate, magnesium chloride, sodium chloride, potassium chloride, iron sulfate, iron chloride, and combinations thereof.

14 . The composition of claim 1 , wherein the composition further comprises a foam stabilizer selected from C 4 -C 20 alcohols, C 12 -C 18 amines, sorbitan esters, polysorbates, fatty acids, and combinations thereof.

15 . The composition of claim 1 , wherein the composition further comprises a preservative.

16 . A method for suppressing and/or extinguishing a Class-B fire, the method comprising applying a foam composition of claim 1 either directly or indirectly to or onto a Class-B fire or directly or indirectly to or onto the fuel ahead of an advancing Class-B fire front or a potentially advancing Class-B fire front.