When doing the calculations required in Sec. 172.225,
(a) The permeability of a floodable space, other than a machinery or cargo space, must be assumed as listed in Table 172.240;
(b) Calculations in which a machinery space is treated as a floodable space must be based on an assumed machinery space permeability of 85% unless the use of an assumed permeability of less than 85% is justified in detail; and
(c) Calculations in which a cargo space that is completely filled is considered flooded must be based on an assumed cargo space permeability of 60% unless the use of an assumed permeability of less than 60% is justified in detail. If the cargo space is not completely filled, a cargo space permeability of 95% must be assumed unless the use of an assumed permeability of less than 95% is justified in detail.
Table 172.240--Permeability------------------------------------------------------------------------
Permeability
Spaces and tanks (percent)------------------------------------------------------------------------Storeroom spaces..................................... 60Accommodations spaces................................ 95Voids................................................ 95Consumable liquid tanks.............................. \1\ 95 or 0Other liquid tanks................................... \2\ 95 or 0Cargo (completely filled)............................ 60Cargo (empty)........................................ 95Machinery............................................ 85------------------------------------------------------------------------\1\ Whichever results in the more disabling condition.\2\ If tanks are partially filled, the permeability must be determined
from the actual density and amount of liquid carried.