Flowline Span Assessment

Integrity management engineering specialists have pioneered integrity management processes over the years working with major operators.

THE PROBLEM

Unstraked free spans exceeding design allowable span lengths were identified on the flowline during risk-based ROV inspections. The free span lengths exceeding the design limits had the potential to cause excessive VIV fatigue damage.

The Solution

• The ROV inspection footage was reviewed to determine span lengths and locations
• Static ultimate limit state stress checks and VIV fatigue analysis were performed on the free spans in accordance with DNV-RP-F105 and DNV-OS-F101
• The assessment confirmed the flowline integrity despite span lengths that are greater-than design allowable. No mitigation was required.

THE RESULT

Risk-based inspection promptly identified changes in free span lengths from the baseline inspection that can potentially lead to unplanned fatigue damage in the flowline.
Engineering assessment was performed using available inspection data to help the operator to confirm system integrity and avoid the cost associated with flowline span mitigation and any associated retrofit for strakes.