What does "isolation" mean in the context of preparing a pipeline or system for hot work, and why does it matter?

A. Physically disconnecting, blanking, or positively isolating the system from any source of flammable product (not just closing a valve, which can leak or be inadvertently reopened) so the line cannot be re-pressurised or re-filled during the work

B. Moving the work to a different part of the ship

C. Switching off the lighting in the work area

D. Isolation only refers to keeping other crew members away from the area

A. Any task lasting longer than 30 minutes

B. Only welding using electric arc equipment

C. Any work involving an open flame, welding, burning, grinding, or any process that produces sufficient heat or sparks to act as a source of ignition for flammable materials, gases, or vapours

D. Only work carried out inside a cargo tank

A. A clear radius of at least 10 metres (or as defined by the risk assessment for the specific task and materials), with all combustibles removed or adequately shielded

B. No clearance is needed if a fire extinguisher is present

C. Clearance is only relevant for work carried out in an engine room

D. 1 metre is always sufficient regardless of the work type