Dnv-rp-f118 - Link

Understanding DNV-RP-F118: A Guide to Qualifying Automated Ultrasonic Testing (AUT)

Reduce Risk: Ensure that critical flaws won't be missed during pipelay operations. dnv-rp-f118

| Limit State | Description | Check example | |-------------|-------------|----------------| | ULS (Ultimate) | Maximum load capacity under extreme environmental conditions (e.g., 100-year storm). | Yield or buckling of steel riser under tension + pressure + bending. | | FLS (Fatigue) | Accumulated damage from cyclic loads (waves, vessel motion, vortex-induced vibration). | 20-year fatigue life with safety factor of 3 (or 10 for inaccessible, non-repairable locations). | | ALS (Accidental) | Survivability after damage (e.g., dropped object, collision, fire). | Residual strength of dented riser. | | SLS (Serviceability) | Functionality under normal operation. | Excessive deflection causing interference with other risers or mooring lines. | | | FLS (Fatigue) | Accumulated damage from

DNV-RP-F118, often cited alongside the offshore service specification DNV-OS-F101, outlines the requirements for demonstrating that an AUT system can reliably detect and accurately size flaws in pipeline girth welds. Traditional radiography (RT) has largely been replaced by AUT in modern pipeline projects due to the latter's speed, safety, and ability to provide three-dimensional data on weld defects. The Core Objective: Probability of Detection (PoD) | Residual strength of dented riser

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