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.