A member of a team of workers dismantling subsea emergency shutdown valves (ESDV) on deck was badly injured when hit by parts of a valve that were ejected with force.
The team had successfully and without any problems already dismantled three (3) valves / ESDV as per the plans for that night. As the last valve was being disconnected, the Grayloc connection between the jumper and valve, along with the gasket inside the line, was ejected with force. The ejected gasket hit one worker on the forehead, resulting in a bleeding wound. The injured person remained conscious throughout and was assisted to the medic for treatment. The worker was treated by the medic and received seventeen stitches to the wound.
Investigation revealed the following:
- The lines had been flushed and isolated two weeks earlier and an isolation handover procedure and isolation certificate provided to the contactor.
- The activity was being carried out under the Site Permit to Work and in conjunction with SAT diving activities.
- No further check of the line was performed prior to starting the disassembly.
- Adjacent lines had been worked on and dismantled with no pressure present.
- Work by divers subsea had taken place on lines in the circuit allowing water to ingress.
What were the causes?
- Unidentified pressure in the line caused the gasket to be ejected with force.
- Lack of monitoring of system behaviour between isolation and the start of the task;
- Lack of safety controls – no one had manually rotated the valve and vented the system after actuator removal, thus ensuring no pressure.