Fill-Coat #2 Casing Filler is a petrolatum wax based corrosion preventative compound used to fill the pipeline casing annulus. It is specifically designed for cold installation out of a 55-gallon drum for small quantity requirements. It prevents corrosion by displacing water that is present and preventing water from re-entering the casing. It remains in a firm gel consistency at ground temperatures commonly found in normal pipeline operations.
Water or water vapor is present in most pipeline casings, making possible galvanic corrosion of the carrier pipe. Also, a "water short" can occur through the water in the casing, allowing cathodic current to flow through the water and on to the pipe in the casing. Under these circumstances, cathodic current is increase and the casing is sacrificed as well. Casing filler prevents this from occurring. Further, in some instances the pipe may be shorted to the casing through a direct metal-to metal contact and filling the casing might correct this condition on some occasions. In any case, it is difficult if not impossible, to cathodically protect pipe in a casing, so that filling of the casing will protect the pipe from corrosion regardless of the circumstances.
When the casing is filled with FillCoat #2, it displaces accumulated water from the casing and prevents new water from re-entering through leaks in the seals or through condensation. Thus, corrosion that might have been occurring is prevented, cathodic current to protect the pipeline in the casing may be reduced, and the sacrifice of the casing by cathodic current flowing through casing is halted. This allows a film of casing filler material to coat the shorted contact surfaces of the pipe and casing. Since Fill-Coat #2 is electrically non-conductive, a metallic short may be corrected.
After being pumped into the casing, the filler remains as a firm gel, pliable enough to allow the carrier pipe to be removed if necessary. It is essentially inert and nonvolatile and will remain unchanged indefinitely.