High potential near miss: working on pressurised pipeline

What happened?

During the dewatering of a 6” flexible jumper, a near miss incident occurred when the pull head was removed whilst it was still under pressure. This resulted in a foam pig that was inside the flexible jumper being unexpectedly ejected by the residual pressure. The pig narrowly missed personnel in the immediate vicinity and landed on the ground approximately 2m away from the jumper end.

The incident had the potential for serious injury to personnel standing in the line of fire. Activities were being controlled and supervised by our member at a third-party worksite.

What went wrong? What were the causes?

Our member noted the following:

• The approved procedure for the pressure testing and dewatering activities was not followed correctly (a vent valve that should have remained opened at the other end of the jumper was closed);
• A ‘working copy’ of the approved procedure was not available at the task location for reference by personnel;
• There was no on-going sign-off being conducted as each task was completed;
• There was no check conducted for positive confirmation that the system was at ambient pressure before starting to remove the pull head to access the foam pig;
• There was no requirement for formal sign-off/handover of system control from the pre-commissioning services company to our members’ personnel who were required to remove the pull head for the foam pig inspection.

What actions were taken? What lessons were learned?

• When lines have been pressurised, isolation and venting processes should be in place, which ensure the ambient pressure is verified before breaking pressure containment;
• Supervision on worksites should highlight safety critical points within the procedures and ensure that they are strictly followed by personnel;
• Where stored pressure or energy is involved, ensure approved procedures contain requirements for formal sign-off/handover of system control, particularly when third party sub-contractors are involved.

Members may wish to refer to the following:

• High potential stored energy incident: inner buoyancy module clamp failure during removal (a casual factor being failure to properly manage the task)
• Fatality: Stored pressure release