3.14 LASHING AND SEALING VALVES AND CONTROLS

All closed valves should be lashed (hand wheels tied with a short length of line), or otherwise positively marked to indicate that they are fully closed.
When the cargo system loading alignment has been completed, an appropriate entry should be made in the deck logbook indicating that the valve setting was completed and verified according to the loading orders. Also log the seal numbers and identity of valves which have been sealed to prevent cargo contamination or environmental pollution. Seals should be robust and brightly coloured (to prevent the valve being accidentally opened because the seal could not be easily seen).
Valves which are particularly critical may be chained and locked as well as sealed, but this should not be done if there is any possibility that the valve will need to be opened in an emergency.
On CCR operated ships, the sealed valves' actuators on the valve control panel should be covered and distinctively marked to indicate sealing. On computer operated cargo control systems, it may be possible for the chief officer (using password access), to disable selected valves. If this is done, the disabled valves must be clearly noted in the loading orders and on the CCR status board.