Dnv-rp-f118 -

DNV-RP-F118 emphasizes that a small number of samples (like 3 or 4) is insufficient to prove reliability.

DNV-RP-F118, often cited alongside the offshore service specification , 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 Traditional radiography (RT) has largely been replaced by AUT in modern pipeline projects due to the latter's speed, safety, and ability to provide three-dimensional data on weld defects.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)

Comparing the AUT results against the actual "true" size of the seeded flaws (often verified later by macro-sectioning the weld). dnv-rp-f118

Creating physical weld samples, known as mock-ups, which contain "seeded" flaws of known sizes and locations.

To achieve a PoD of 90% with 95% confidence, a minimum of 29 samples is generally required. However, for complex welds like double V submerged arc welds, DNV-RP-F118 recommends significantly more, often at least 91 samples . Key Components of the Qualification Process DNV-RP-F118 emphasizes that a small number of samples

According to the DNV-RP-F118 Guidelines , a qualification program typically involves several stages:

Understanding DNV-RP-F118: A Guide to Qualifying Automated Ultrasonic Testing (AUT) The Core Objective: Probability of Detection (PoD) Comparing

Performing multiple passes on these mock-ups to collect ultrasonic data.