Recent inspections for potential pipe corrosion at terminal show encouraging results

By TOM KUCKERTZ
Project Manager for Terminal Operations

Some of the council’s concerns regarding the unknown condition of the crude oil piping at the Valdez Marine Terminal have been answered by inspections performed this summer by Alyeska.

Causeway to Berth 4 at the Valdez Marine Terminal. Scaffolding has been installed and covered with plastic tarps to keep Alyeska's inspection crews and exposed piping dry during inspection. Photo by tom Kuckertz.
Causeway to Berth 4 at the Valdez Marine Terminal. Scaffolding has been installed and covered with plastic tarps to keep Alyeska’s inspection crews and exposed piping dry during inspection. Photo by tom Kuckertz.

In 2012, a routine inspection by Alyeska personnel of the 20-inch vertical riser pipes that feed crude oil to the loading arms on Berth 4 at the terminal revealed the existence of serious corrosion in some of the girth welds. Girth welds are welds that extend around the diameter of a pipe, typically used to join two sections of pipe.

Following this discovery in 2012, the remaining riser pipes on Berths 4 and 5 were subjected to additional inspections. More occurrences of vertical pipe girth weld corrosion were found and repaired. The cause of the corrosion in that particular region was attributed to water collecting under the pipe’s insulation in combination with a missing anti-corrosion paint coating in the vicinity of the girth weld.

In response to these discoveries and in substantial agreement with recommendations of a council sponsored review of corrosion management practices by Dr. Rust Inc. in 2012, Alyeska significantly expanded their 3 year ongoing pipe inspection efforts. These inspections will now include the majority of the girth welds in crude oil piping under insulation at the terminal with over water piping as a first priority, beginning this year.

In August, Alyeska reported that it was well-along in accomplishing the inspection of the girth welds for the over water piping to Berth 4 and invited council staff to observe its inspection activities. Alyeska had erected scaffolding at multiple locations to remove insulation at the girth welds to inspect, clean, and repair as needed.

Girth weld in the crude oil piping to Berth 4. The weld is showing superficial amounts of corrosion that does not materially affect the integrity of the weld. The coating applied to the visible piping segment during construction appears to be in remarkably good condition. Photo by Tom Kuckertz.
Girth weld in the crude oil piping to Berth 4. The weld is showing superficial amounts of corrosion that does not materially affect the integrity of the weld. The coating applied to the visible piping segment during construction appears to be in remarkably good condition. Photo by Tom Kuckertz.

The good news is all corrosion found during the recent inspection tended to be superficial and could be easily cleaned and then the weld recoated. Alyeska also reported that it accelerated the completion date for similar inspections of Berth 5. Originally planned for 2014, the Berth 5 inspections are now expected to be largely accomplished in 2013.
The council is in the midst of developing a project to assess the current state of inspection technologies, known in the industry as “in-line-inspection”, or colloquially as “smart pigging,” for their applicability to Alyeska’s terminal piping. Much of the crude oil piping on the terminal has historically been very difficult to inspect because of many turns and sections which are either buried or over water and covered by insulation. Alyeska has indicated that it is in the midst of developing a project that would add the capability of performing internal in-line inspections using these technologies at the terminal. The council has requests pending with Alyeska for more information regarding the project.

The bottom line is that the council’s immediate concerns regarding the unknown condition of the over water piping have been allayed to a considerable extent by Alyeska’s recent inspection activities and the excellent overall condition of the

Once the corrosion is cleaned from an affected girth weld, the weld is recoated and then the exposed pipe segment is re-insulated with a protective barrier that prevents the reintroduction of water. The girth weld shown here is ready to be reinsulated. Photo by Tom Kuckertz.
Once the corrosion is cleaned from an affected girth weld, the weld is recoated and then the exposed pipe segment is re-insulated with a protective barrier that prevents the reintroduction of water. The girth weld shown here is ready to be reinsulated. Photo by Tom Kuckertz.

pipe that has been observed. The need to inspect and quantify the presently unknown condition of the remainder of the 35-year-old piping at the terminal remains. The council looks forward to hearing more about Alyeska’s in-line inspection technology plans for the terminal as that project progresses.

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