The sulfates and/or phosphates are true fire retardants, since they affect the combustion process. When used in equal amounts, phosphate is more effective than sulfate as a retardant. Phosphates have been shown to be more effective at reducing the fire’s rate of spread, rate of weight loss and the rate of energy release. When using sulfate, this difference in effectiveness is overcome by using more sulfate than phosphate per mixed gallon or retardant slurry. Therefore, sulfate-based and phosphate-based long-term retardants are considered equally effective when used on fires. Since sulfates cost less than phosphates, the use of more sulfate per gallon does not necessarily increase the retardant’s cost above that of using phosphate.

Research studies have shown an acceptable amount of long-term retardant is between two and four gallons per 100 square feet for most fuel types. A two-gallon coverage rate would produce a uniform coverage of 1/32 inch in depth (the thickness of a dime).

The components of long-term retardant are:

• Fire retardant salts (alone or in combination)
  • Ammonium sulfate
  • Diammonium phosphate
  • Monoammonium phosphate
  • Ammonium polyphosphate
• Preservative or spoilage inhibitor (found only in gum-thickened retardants)
• Corrosion inhibitor(s)
• Coloring agent
• Thickening agent
  • Guar gum or clay

The liquid concentrate is proportioned at a pre-set ratio with the water while both pass through a blender on their way to the loading pump. The water and liquid concentrate are then mixed together as they pass through the loading pump on their way to the air tanker or helicopter dip-tank. Mixing is instantaneous in the pump. This eliminates the need to store pre-mixed retardant.

FIRE-TROL LCG-F and R are blended/mixed at a ratio of 4.75 parts water to one part liquid concentrate. With this mix ratio, 10,000 gallons of LCG-F or R produces approximately 57,500 gallons of mixed retardant.
FIRE-TROL liquid concentrate is delivered to the air tanker or helicopter base by tanker truck. The LC is pumped into a storage tank. This is the only handling required. One person can handle the entire LCA-F and R or LCG-F and R blending/mixing

POWDER

A batch mixer is used to mix FIRE-TROL GTS-R and FIRE-TROL 300-F powder long-term retardant. The retardant powder is supplied in a Semi-Bulk Container (SBC) holding a pre-measured quantity of product. The use of a pre-determined amount of powder and water in the batch mixer permits the mixing operation to be easily controlled. This system provides for superior quality control of both the viscosity (thickness) and salt content of the mixed retardant.

FIRE-TROL GTS-R and 300-F, with guar gum as a thickener, require a mixer with a propeller-type agitator. When FIRE-TROL GTS-R packaged in a 2,200 pound SBC is added and mixed with 1,325 gallons of water, 1,457 gallons of long-term retardant is produced. When FIRE-TROL 300-F packaged in a 2,200 pound SBC is added and mixed with 1,243 gallons of water, 1,373 gallons of long-term retardant is produced. The mixed retardant is then pumped into storage tanks where it is held until loaded onto an air tanker operation.