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Those who are interested can take a look at my other articles at http://www.haolin.biz/UserForum/blog/bloghome.html. Wildland fuels (trees, shrubs, and grasses) are primarily composed of cellulose and a small amount of aromatic hydrocarbons. Phosphates containing thermally volatile cations are the most effective in suppressing the combustion of cellulose fuels. When the treated fuel is heated, cations are released, and the remaining phosphoric acid then reacts with cellulose molecules to form esters. The phosphate ester is subsequently thermally degraded through dehydration, resulting in the release of water vapor and the deposition of graphitic carbon, making it non-flammable under atmospheric conditions. Ammonium phosphate has been found to be the most effective and environmentally friendly flame retardant, as it reduces the intensity of combustion and the speed of spread of fuel in forests and shrubs. It has been proven that monoammonium phosphate (MAP), diammonium phosphate (DAP), and mixtures of the two are the most suitable for dry powder flame retardant concentrates. Fertilizer-grade concentrates (10-34-0 and 11-37-0) have high water solubility due to their content of concentrated ammonium phosphate (polycondensed long chains), allowing for high-concentration formulations; they are used in concentrate-type flame-retardant formulations. In strict adherence to **environmental and toxicological requirements, the flame retardant compositions for forestry are specified to remain within acceptable limits. The only forest flame retardant was approved by the former federal land management agency. Most forest flame retardants are applied from the air, that is, via fixed-wing or rotary-wing aircraft. When the main component is ammonium phosphate (MAP, DAP, liquid ammonium polyphosphate, or their mixtures), some other functional components are also required. Such flame retardants are available as dry powder or concentrate. When in use, before transferring it from the container to the application platform, mix these two concentrates or dilute them with water first. The mixing ratio is determined by **laboratory fire performance testing. When the flame-retardant solution is applied indirectly (to create a fire barrier in front of an advancing fire), the water that has been mixed in or diluted evaporates before the flame front arrives, resulting in no significant impact on the flame-retardant properties. Forest fire retardants are most effective when used indirectly. An ammonium phosphate flame retardant is used to form a fire barrier, which remains effective until it is removed from the fuel through rainfall or other dissolution methods. Therefore, ammonium phosphate flame retardants are known as long-term flame retardants. Rheological modifiers are added to forest flame-retardant formulations; when exposed to the shear forces generated by an aircraft taking off, they help maintain a compressed flame-retardant cloud. Ideally, the properly thickened solution will squeeze in and adhere to the fuel. Thus, the path and the surface fuel were covered with the predetermined application amount, forming a continuous flame-retardant line. Generally, for some airdrops, it is necessary to prepare the required shape of flame-retardant and fire-resistant wires. This requires the solution pilot to be visible, so that the droplets can come together to maintain the continuity of the effective line segment. This is perfected by the contents of the coloring agent. Applying flame retardants containing red iron oxide pigments in the air does not pose a problem of semi-permanent pollution to the local landscape. The public considers that flame retardants that change color easily in visible areas are preferable, to avoid persistent red staining. When in natural light, the pigments of the color-changing flame retardant degrade and return to the color of soil, allowing it to blend in with the surrounding environment. Other components include corrosion inhibitors and flow modifiers, such as calcium phosphate (TCP), which can be added to forestry flame-retardant formulations. It is important that flame retardant formulations meet strict requirements, particularly with regard to the corrosion of steel, aluminum, and brass, as well as of aircraft hardware that comes into contact with them. TCP is used to ensure free flow from the container to the mixer when using dry powder flame retardants.