• Published: 20 Jun 2011
  • Incident ID: 3318

Person struck by clamp while carrying out seal ring replacement

Cause & Consequence

  • Moving, flying or falling object
Incident Consequence

Incident Location

Fixed Installation

Incident Activity


Incident Info Source

Chevron Fiona Gibson

Specific Incident Equipment

The equipment involved in the incident was a Techlok clamp which was being removed.

Lessons Identified

Incorrect methodology used for breaking Techlok seal rings:

  • IPs not trained in removal of Techlok joints
  • IPs did not consider that the pipework had potential to repressurise and did not follow requirements of risk assessment (which stated that a Plant Operator must be present when breaking containment)

Pressure in line when clamp removed:

  • Isolation integrity checks not carried out by Plant Operator strictly as per procedure (isolation integrity was re-checked after 5 minutes instead of procedural requirement for check after 30 minutes)
  • Poor understanding of procedural requirement for separate risk assessment where single valve isolation is used

Incident Recommendations

Review Operator and Contractor competencies for breaking and making Techlok jointsReview Contractor hazard perception training, particularly with respect to trapped pressure and pipe strain within process pipeworkImprove Safe Isolation of Plant procedure:

  • Clarify requirement for risk assessment whenever hazardous inventories are to be isolated using a single block and bleed
  • Add requirement for integrity of relevant isolations to be confirmed immediately before breaking containment

Reinforce requirements for Isolating Authority to comply with isolation integrity testing timeframes and updated procedural requirementsAll personnel reminded to comply with requirements of risk assessment when carrying out permitted tasks

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