Standards › Pipelines

DNV-RP-F105

Free spanning pipelines — VIV and fatigue

DNV-RP-F105 governs free-spanning subsea pipelines — the vortex-induced vibration and the fatigue it drives. Ask Deckhand to screen a span for allowable length.

Run it on Open Deck

What you can ask it to do

  • Estimate a span's natural frequencies and screen it for cross-flow and in-line vortex-induced vibration.
  • Work out the allowable free-span length for the seabed and flow conditions.
  • Flag where a span needs intervention (rock dump, supports) to control fatigue.

Related standards

DNV-RP-F105 Free span Vortex-induced vibration Span fatigue

Part of Subsea, Pipelines & Integrity · see the platform engine

Questions

Why are free spans a problem?

Where a pipeline crosses a depression it spans unsupported; current over the span sheds vortices that make it vibrate, and the cyclic stress accumulates fatigue. DNV-RP-F105 is the recommended practice for assessing it.

What is the allowable span length?

The longest unsupported length that keeps vortex-induced vibration and the resulting fatigue within limits for the seabed and flow conditions. Deckhand estimates it and flags spans that need intervention.

Run DNV-RP-F105 on your own inputs

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