This paper presents observations and guidelines associated with conducting hydrostatic pressure tests of pipelines and/or process equipment, such as vessels. The potential concerns for hydrostatic pressure tests relate to the water itself, including any suspended solids, dissolved oxygen, or any Sulfate Reducing Bacteria (SRB) or Acid Producing Bacteria (APB) that may be present in the test water. Recommendations of several major crude oil and natural gas producers, pipeline companies, chemical suppliers and service companies have been reviewed, including “best practices.” Hydrostatic pressure test water should be completely removed from the system within 28 days, including any small remnants of water from low spots or deadlegs. However, if the period of time following the introduction of the test water and the beginning of operations exceeds 28 days, then it would be appropriate for a “dry” or “wet” lay-up in order to preserve the integrity of the base metals and prevent internal corrosion. This paper presents general observations and recommendations related to “dry” and “wet” lay-ups, including filtration requirements and specific treatments for oxygen scavengers, biocides, and corrosion inhibitors.
Keywords: Hydrostatic, Pressure Test, biocide, glutaraldehyde, THPS, Sulfate Reducing Bacteria, SRB, corrosion inhibitor, oxygen scavenger, ammonium bisulfite, ABS, pickling, wet lay-up, dry lay-up, dwell time