Fill-Coat #1 Pipeline Casing Filler is a petrolatum based corrosion preventative compound used to fill the annulus of pipeline casings. It prevents corrosion by displacing water that is present in the casing and by preventing water from reentering the casing.
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 increased 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 casing, so that filling of the casing will protect the pipe from corrosion regardless of the circumstances.
When the casing is filled with Fill-Coat #1, 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 water is halted. Hot, liquefied casing filler material can, in some instances, penetrate corroded, scaly pipe to allow a film of casing filler material to coat the shorted contact surfaces of the pipe and casing. Since Fill-Coat #1 is electrically non-conductive, a metallic short may thus be corrected.
After being pumped into the casing, the hot casing filler cools and sets up as a firm gel and remains pliable enough to allow the carrier pipe to be removed if necessary. It is essentially inert and nonvolatile and will remain unchanged indefinitely.