Cause & Consequence
- Fire or explosion
- Control of work
Description of Process
Emergency over speed protection - Controlling ignition sources from diesel engines by ensuring the Rigsaver air shut off valves are serviced, maintained and functional.
Instances have been reported that 80% of Rigsaver valves tested on one rig did not close upon command
Description of Incident
Diesel engines used for offshore power generation should be fitted with a shut off valve that blocks the engines intake system, cutting off both the external fuel source and air required to keep the engine running, preventing the catastrophic consequences of diesel engine runaway.
Legacy 11" air shut off valves manufactured prior to January 2014 are likely to require modification and servicing to ensure safe activation of the valve.
After extended periods of vibration the valve could require a higher air pressure to activate or may have a tendency to false trip.
See the attached safety bulletin from Rigsaver.
Good Practice Guidance
Schedule regular function testing of the Rigsaver valves using the emergency stop to actuate the valve pneumatically; this should be performed every 2-4 weeks. The factory maintenance schedule should be adhered to and it is highly recommended that a testing log is kept.
Service schedules should be reviewed and integrated into work procedures. The maintenance schedule activity for this component is based on 4000 hour intervals
Operators of 'Legacy style' valves should upgrade the valve by replacing the cover kit and then utilize the service schedule to extend the life of the valve. Operators of phase 2 'next generation' valves should follow the service schedule to optimize the valve performance