210. Zone definitions does not include,

A. Zone 0: Area in which an explosive gas atmosphere is present continuously or is present for a long period.
B. Zone 1: Area in which an explosive gas atmosphere is likely to occur in normal operation.
C. Zone 2: Area in which an explosive gas atmosphere is not likely to occur in normal operation, and if it does occur is likely to do so only infrequently and will exit for a short period only.
D. Zone 3: Area in which explosion can occur on a LNGF vessel