No HazardRisk Category

Cause/Failure mode descriptionSafeguards/Risk reducingS E C T R

Loading1 Overloading X X X X Danger overloading cargo tanks

with effects on structure/equipment and possibly creating gas pockets onboard

Operational procedure and alarm system

2 LNG Spill on deck or to sea X Faults in connection or pipes leading to spill

Operational procedure, maintenance

3 Filling liquid in to compressor and boiler areas

X X During overloading LNG is overflowing into neighbouring rooms causing damage to equipment/structure, caused by malfunction of equipment and human failure

Operational procedure and alarm system

4 Fault in operational Procedure X X Tanks are being filled too high due to commercial pressure, calculating that the boil off rate will reduce the high level in the tanks after a while

Operational procedure

5 High movements in LNG Transfer system X LNG transfer system is designed to withstand a certain movement and will break causing spillage if violated

Operational restrictions related to weather and wave conditions

6 Lack of communication with shore personell

X Leading to overloading Crew awareness and training

7 Faults in ballast system or fault operation of ballast system

X Causing high movement or displacement movements in LNG transfer system

Operational procedure and alarm routines

8 Lack of crew competence and training X Lack of stability during loading/unloading may lead to roll over

Alarm routines, crew awareness

9 Roll-over X Lack of stability during loading unloading may lead to roll-over

Alarm routines, crew awareness

No HazardRisk Category

Cause/Failure mode descriptionSafeguards/Risk reducingS E C T R

Unloading1 Overfilling other tanks X X Fault operations may pump LNG

into other tanks leading to them overfilling with secondary effects

Alarm system, barriers

2 Tank depressurising X X Working the pumps when the tank is empty, will depressurise the tank and it may collapse, membrane will be damage, sphere structure may buckle (moss type)

Operational procedure, Alarm system, barriers

3 High movements in LNG Transfer system X LNG transfer system is designed to withstand a certain movement and will break causing spillage if violated

Operational restrictions related to weather and wave conditions

4 Fault in operational Procedure or failing to follow procedure

X X Tanks are being filled too high due to commercial pressure, calculating that the boil off rate will reduce the high level in the tanks after a while

Operational procedure

5 Being struck by passing vessels X May cause tank rupture and secondary a high rate spillage

Radar watch, collision alarm

6 Lack of communication with shore personell

X Leading to overloading Crew awareness and training

7 Faults in ballast system or fault operation of ballast system

X Causing high movement or displacement movements in LNG transfer system

Operational procedure and alarm routines

8 Lack of crew competence and training X Lack of stability during loading/unloading may lead to

Alarm routines, crew awareness

roll over9 Clogging up pumps with ice cubes X X Ice clogging may result if water

gets into system causing ice formation. This may damage pumps and cause operational failure

System design, crew awareness

10 Roll-over X Lack of stability during loading unloading may lead to roll-over

Alarm routines, crew awareness

Scenario