Note: Users should note that the example provided represents
one way of handling an assessment as other approaches could be equally
effective.
The assessment is developed adopting the following steps:
Step 1 Identification of all essential
systems and any required auxiliaries and support systems.
Step 2 For each deck of each MVZ, determination
of which essential systems are present.
Step 3 For each essential system that is
located in the MVZ under analysis, verification of the availability
of an alternative in another location.
Step 4 Essential systems without a suitable
alternative in another location must be protected from a fire/flooding
casualty.
Step 5 For each critical system, determination
of how the cables, pipes, components will be protected. A hierarchy
for protecting critical systems is proposed as follows:
| 1. First Solution
|
|
Provide an alternative in a MVZ not affected
by the casualty
|
Example: A main power cable for the GMDSS system passes
through the MVZ on deck 3. In a fire this cable could be damaged.
An emergency power cable is routed from a different direction to the
navigation bridge that does not pass through this area. The conclusion
is that further analysis is not needed. Damage to the power cable
does not affect the ship's safe return to port capability.
| 2. Second solution
|
|
Protect the essential system within the MVZ under analysis
|
Example: In the case of the a.m. power cable, it is
determined that only a short length of cable passes through the MVZ
under consideration, located 5 m above the deck. An A-60 trunk is
installed to protect the cable to preclude fire damage.
| 3. Third solution
|
|
Provide a repair or manual action to compensate for loss
of the system
|
Example: Another essential system cable is
analysed, and it is determined that the cable is routed throughout
the MVZ at various levels and construction of an A-60 trunk is not
practicable. Instead, a repair cable is prepared and staged with necessary
tools at a protected location. If the cable is damaged from a fire
in the MVZ under analysis, the crew is able to temporarily re-route
power from another location using the repair cable.