Pipe Casing Injection for Corrosion Protection of Mechanically Shorted Cased Crossing
Vessel Assessment
The casing crosses an interstate and a main street. There is a slight decline going away from the aqueduct. The bottom casing was located at the end of the decline, and the top casing was located near the aqueduct. It should be noted that in the days prior to the injection, the end seals were refitted with a Viscotaq material, and a 5 psi pressure test was completed. These excavated ends were back filled and covered.
Conclusion & Recommendations
The vent pipe used for the injection had to be cut and threaded for the injection fittings. A threaded coupler was used to replace the cut section of the vent pipe to restore the “candy cane” like shape. The other vent pipe only needed a rubber coupler.
The injection went quite well. Every pail of PGH-400 and 80% of the PGH-300 was able to be added to the inhibitor slurry during the injection. A person stood watch over the opposite side of the casing to see if there was any discharge. None was reported. The slurry was injected into the low end of the slope.
