Introduction
All oil & gas industry refineries and chemical plants conduct scheduled plant turnarounds and shutdowns for maintenance, inspection and engineering projects, which generally involve new pipe fabrication and butt welds that require Nondestructive Examination (NDE) inspections. Planners and engineers are constantly looking for ways to improve the Turnaround (TAR) or plant shutdown performance and schedule. They would prefer not to conduct Radiographic Testing as this requires significant safety precautions such as establishing radiation boundaries, which can take significant time from the daily work schedule and cause other complications to work execution. The purpose of this article is to explain how to successfully introduce the Ultrasonic Testing (UT) Method, Phased Array Technique (PAUT), into a plant TAR as an alternative to common film Radiographic Testing for the inspection of pipe butt girth welds for engineering and maintenance projects.
Film based Radiographic Testing (RT), and more recently Computed Radiography (CR), for inspection of piping projects or general maintenance and pipe replacements or repairs is common in plant TARs. This type of inspection with radiation boundaries using magenta and yellow tape is almost expected by the general workforce as they arrive at your plant for an extended TAR or shutdown. Radiation safety boundaries are included in all contractor workforce safety training not only in the United States but globally. Planning schedules must include RT at evening or third shift, break and lunch times, or laydown areas just outside of the TAR plant boundaries to avoid interrupting other work. Welders are used to completing their pipe butt welds on day shift and getting results the next day.
The introduction of PAUT is a challenging effort initially, but can have a very positive impact on your first TAR and become a routine inspection for future TARs. When fully implemented, radiation safety boundaries can be reduced significantly or eliminated altogether. As radiation issues are not a concern for PAUT, all inspection for pipe butt welds can be completed on the first shift or day shift. Weld inspection results can be provided on first shift and many times soon after the welder has completed his pipe butt weld. The welder and his foreman can receive immediate feedback on concern areas of the weld during the welding process or repairs with exact dimensions to the repair that were not possible in radiographs.
This article will provide proven steps to follow and suggestions on how to successfully implement PAUT into your next plant turnaround. The article will also include confirmed special Phased Array Testing techniques to assist your NDE Company provider and make your plant turnaround more cost efficient and enhance safety with less radiation restriction boundaries in a crowded workforce turnaround.
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