• Published: 12 May 2011
  • Incident ID: 3138

Failure to Follow Safe Systems of Work (MoC & QA/QC)

Cause & Consequence

  • Failure of vessels or pipework
Incident Consequence

Incident Location

Drilling unit

Incident Activity

Any Activity Type

Incident Info Source

Specific Incident Equipment

Pulsation Dampener, Mud Pumps, Pipework

Lessons Identified

Investigation found the engineering firm assigned to the task of repairing the dampener, verbally agreed to fit 12 x 1/12 UNF 12 TPI threaded studs and follow this with a pressure test to verify the unit was still fit for purpose. However, the engineering firm deviated from this work scope and fitted pressed parallel sleeves without consulting the operator. The dampener was also not pressure tested prior to being dispatched offshore. The operator's shore base personnel assumed certification for pressure testing went to the rig with the repaired equipment. The operator's rig personnel assumed their shore based support personnel had the certificates. The dampener was fitted without any verification it was fit for the intended service.Both the engineering firm and the operator failed to ensure their respective processes addressing change management, design validation, verification and certification were appropriately followed and that all personnel with responsibility for the implementation of these processes had been appropriately trained in them.Key Lessons:Appropriate requirements for QA/QC including validation, verification, testing and certification must be adequately documented when preparing to have plant and equipment repaired, refurbished or modified. Repaired or refurbished equipment must be appropriately inspected and, where necessary, tested and verified prior to bringing it back into service

Incident Recommendations

Operators must take all reasonably practicable steps to ensure that: : plant and equipment are safe and without risk to health; : safe systems of work are effectively implemented and maintained; : information, instruction, training and supervision necessary for personnel to undertake their activities are provided. Suppliers of plant must take all reasonably practicable steps to: : ensure it is in such a condition as to be, when properly used, safe and without risk to health, and; : carry out, or cause to be carried out, the research, testing and examination necessary to discover, and to eliminate or minimise, any risk to health or safety that may arise form the condition of the plant

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