Welding Failures I Have Known, Interesting cautionary tales from Metals & Welding  expert, Dr Jesse A Grantham, PE

The Case of the Fracking Pump Miscommunication

Fracking Pumps and Tanks Set-up at WellsiteThe Problem:

In the litigation, the Buyer alleged that the Original Equipment Manufacturer (OEM) welding was to have been in accordance with AWS D1.1 Structural Welding Code – Steel.   The code stated that complete information regarding base metal, type, size, and NDT of all welds shall be clearly shown on the plans and specifications provided to the OEM.  The contract documents and shop drawings did not indicate which joints required a specific assembly order, welding sequence or Nondestructive Testing (NDT).  The Buyer’s drawings depicted incorrect welding symbols. The Buyer referenced internal corporate specifications that were unavailable to the OEM.  The OEM was ordered by the Buyer to commence welding in the absence of all necessary information from the Buyer. 


My Assessment: 

When a Complete Joint Penetration (CJP) weld is considered critical to the structure being welded the Engineer should specify the proper welding symbol and NDT required to verify the internal integrity of the weld.  The Buyer drawings and specifications did not specify NDT of welds.  Without a NDT call-out, only visual inspection criteria apply.  Visual inspection of a completed weld cannot internally verify a CJP weld.

Fracking PumpThe Consequences: 

The Buyer reported that NDT by Ultrasonic Testing (UT) was independently performed on 108 pumps in inventory before notifying the OEM.  One pump, returned from field service, had cracked in the weld region of interest. There was no consideration for what the in-service pump had experienced, mounting support, mis-alignment, unintended vibrations in-service or vibrations while in transit.  The Buyer’s report did not state the hours of pump operation, pressures and unavoidable wear and tear on the pump from operation beyond the original service life of the pump.  The Buyer’s report did not address additional in-house testing conditions that the pump may have been experienced prior to field service and UT.

The Lessons Learned:

The AWS standards do not address rejection of all products welded by an OEM based on weld inspections of a single item.  The Buyer did not have a basis to claim improper welding or to demand repair, replacement or UT of all the pumps at the OEM expense.  

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Welding Failures I Have Known, Interesting cautionary tales from Metals & Welding  expert, Dr Jesse A Grantham, PE