According to a comprehensive 2026 guide from Therness on PAUT weld inspection, the combination of Phased Array Ultrasonic Testing (PAUT) and Time-of-Flight Diffraction (TOFD) is increasingly the default volumetric approach for Code Class 1 pressure boundaries under ASME Section V Article 4, and for EN 13480 piping systems where radiography is impractical.
Why pair them? PAUT delivers full-volume B-scans, S-scans, and C-scans with excellent sizing and imaging of planar defects like lack-of-fusion and undercut. TOFD provides independent through-thickness crack tip detection and root-to-cap sizing, especially for planar defects that RT routinely misses. Together, they cover each others blind spots.
For pressure vessels, subsea pipelines (DNV-ST-F101), and rolling stock frame welds (EN 15085 CL1), the PAUT+TOFD combo now produces the auditable image record that notified bodies require without the radiation shielding logistics of RT.
The shift is clear: from operator-dependent single-method NDT to encoded, image-based, dual-method volumetric coverage. What is your shop standardizing on for critical welding?
Source: Therness, Phased Array Ultrasonic Testing (PAUT) for Weld Inspection, 2026