Cause & Consequence
- Uncontrolled release of a flammable gas or liquid
Specific Incident Equipment
Gas Compression [GC]: General [GN]- Diesel Header tank inlet valve
The inlet valve failed to close on a high level alarm because its actuator was found to have seized in the mid position. The maintenance strategy for valve actuators was “maintenance on failure”. The valve and actuator had been replaced about 12 months prior to the incident. Because of problems in the past with the inlet isolation valve sticking, operations had put contingency arrangements in making sure that the operators were aware of this potential and they knew where the manual isolation valve was (which was located 2 decks below the tank).
The diesel overflowed from the bund because the drain line to the open hazardous drains was blocked by grit and debris. The size of the bund is sufficient to have contained this spill and so it is believed that the bund was full of water when the leak occurred.
1 Repair inlet valve & actuator and review suitability of current maintenance strategy
2 Clear drain of grit/debris and institute a policy to regularly inspect that bunds are clear. Also bund drains to be capped during gritting operations and checked on completion of the work.
3 Raise awareness of incident at safety meetings