Case Study

Wharf Piping Over Water

Marine oil terminals are the lifeline of San Francisco area refineries. Tankers loaded with crude oil enter marine terminals in San Francisco Bay, where the crude is then sent to refineries for processing via pipelines running under or adjacent to a wharf. Finished products like gasoline and diesel are often loaded and shipped out through the same terminals.

Inspection and repair of the 30- to 50-year-old wharf piping had always been a tenuous process for QualSpec client ConocoPhillips. The pipelines are very close to the water, so wave action and rising tides make it hard to keep scaffolding intact. Access below deck is difficult, and the wharf must remain open during inspection to maintain refinery operations.

Complicating matters further, the San Francisco Bay and surrounding wetlands are environmentally sensitive and fall into many different jurisdictions. Complex environmental, safety and permitting issues are associated with any marine oil terminal projects.

“Our key goals were to have a good assessment of the lines’ condition and to make sure they were safe to operate,” said Brian Jack, inspection superintendent for the ConocoPhillips facility. “Being in a particularly environmentally sensitive area, even the very smallest of leaks is a big deal to us.”

With those goals in mind, ConocoPhillips approached QualSpec about using a rope access crew to inspect and, as needed re-coat and repair all wharf piping over water.

Rope access brought QualSpec’s technicians near enough to the pipes to conduct close visual inspection and pit gauging, assessing localized corrosion and minimizing the risk of pinhole leaks. The crew found that long-range ultrasonics and hydrotesting were not always reliable tools for finding and assessing localized external corrosion and did not reveal isolated deep pitting.

The projects also had several maintenance components were critical to performing a thorough inspection. Hand scrapers and pneumatic needle guns were required to remove all loose mill scale, rust and other detrimental foreign matter prior to pit gauging. Abrasive blasting was impractical, as all paint chips and debris had to be contained to prevent contaminating the bay and exposing workers to lead and other hazards.

The pipes had to be lifted to inspect the contact points between the pipes and the support bents, repair the coatings and install new support material installed under the pipes. When traditional lifting techniques such as jacks or cranes were impractical do to clearance and weight limits, a specially designed platform was fabricated and a system of air-lifting bags deployed to safely raise the pipes clear of the wharf support bents.

QualSpec rope access technicians also performed or facilitated repairs including replacing pipes, welding sleeves, engineering fiberglass wraps and applying new coatings. The successful completion of the ConocoPhillips job led to other similar projects in the Bay Area.

“Overall, we found QualSpec’s rope access service to be an excellent value for this work,” Mr. Jack said. “Much faster than staging!”

Comments are closed.