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Archive for November, 2010

Tonight we have the opportunity to go into a major sporting arena and perform a weld repair on a pressure vessel. After being in the pressure vessel industry for almost 12 years I sometimes forget that not everyone understands what is involved in this type of undertaking. The repair itself is very simple. The unit has been in service for the last fourteen years and after years of vibration a pinhole or crack has promulgated through the heat effected zone around one of the welds. So the repair will consist of grinding out the defect and welding in new material. Simple enough. It’s the paperwork side of things that most people are not familiar with. ASME does not actually have a “Code” for the repair of Section VIII, Division 1 pressure vessels. Repairs fall under the Nation Board of Inspectors Code (NBIC). The National Board is the agency that contends with the requirements for repairs and alterations. The following list is typical of the process for a repair:

  • Investigate the repair that is required
  • Procure or purchase a copy of the original U1-A report from either the manufacturer or The National Board
  • Review the original U1-A to verify materials of construction, Fabrication requirements, Examination requirements, and Testing requirements
  • Prepare a repair plan that includes a field traveler with hold points for the Authorized Inspector (AI)
    • Identify the weld procedure to be used
    • Identify the welder to be used and verify his/her qualifications
    • Prepare any drawings, calculations, and or engineering data
    • Procure and review documentation of any new material that must be utilized
    • Specify and non-destructive testing that is required
    • Specify any final inspection requirements
    • Specify any Post Weld Heat Treat requirements
    • Specify the type and range of any pressure test that is required
    • Prepare a nameplate
    • Prepare applicable R Form
    • All of the above information must be available for the AI to review
    • Perform the repair as stated in the repair plan
    • Perform testing as required by the NBIC
    • Sign off on the appropriate documentation

As you can see there is more to a “Code” repair the simply fixing the weld. Depending on the vessel the testing portion of the repair plan may take a substantial amount of time. Keep all of these items in mind when you call a company asking that a repair be made the same day as same day service tends to cost a little more. Here at Precision Pipe we jump at these opportunities to start new relationships that hopefully last a life time.

 

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