Reality: While the title says "pipeline systems," the mooring industry has widely adopted its annexes and cross-reference sections. Many FPSO operators require F118 compliance for mooring integrity as a condition of insurance (e.g., from Nordic Marine Insurance).
This article is for informational purposes. Always consult the latest official DNV documents and qualified engineers for actual design decisions.
DNV-RP-F118 is a critical Recommended Practice (RP) titled "Pipe Girth Weld AUT System Qualification and Project Specification Procedure Validation". It serves as a technical framework for qualifying Automated Ultrasonic Testing (AUT) systems used specifically for submarine pipeline girth welds. Core Purpose and Scope
The document provides the industry-standard methodology for proving that an AUT system can reliably detect and accurately size flaws in pipeline welds. It is most frequently used in conjunction with the DNV-ST-F101 (formerly OS-F101) code for submarine pipeline systems. Key Technical Requirements dnv-rp-f118
The standard focuses on statistical confidence in flaw detection. Some of its most notable requirements include:
Statistical Evidence: It requires a high level of confidence in the Probability of Detection (PoD). For instance, a common benchmark is achieving a 90% PoD with 95% confidence.
Sample Size: To reach this level of confidence, the standard recommends significant sample sizes. While a basic statistical sample might require 29 samples, DNV-RP-F118 often recommends much higher numbers—such as a minimum of 91 samples for double V submerged arc welds—to ensure reliability. Reality: While the title says "pipeline systems," the
Qualification Components: The process involves a thorough review of technical documentation, operating methodology, and quality assurance systems. The Qualification Process
According to the guidelines, qualifying an AUT system typically involves:
Repeatability and Reliability Tests: Planning and executing programs to ensure the system performs consistently. One of the most actionable parts of DNV-RP-F118
Supplementary Testing: Combining AUT results with other Non-Destructive Testing (NDT) and destructive testing to verify accuracy.
Sizing Accuracy: Establishing not just if a flaw is detected, but how accurately the system can measure its dimensions. Where to Find the Full Text
The official, up-to-date full text is available through the DNV (Det Norske Veritas) Rules and Standards portal. While some summaries or older research papers referencing the process can be found on sites like Scribd or ResearchGate, the most authoritative version for professional project validation should be sourced directly from DNV.
One of the most actionable parts of DNV-RP-F118 is the checklist for the 5-year special period integrity review. This must include: