18.8.1 Under normal operational circumstances,
personnel shall not enter cargo tanks, hold spaces, void spaces or
other enclosed spaces where gas may accumulate, unless the gas content
of the atmosphere in such space is determined by means of fixed or
portable equipment to ensure oxygen sufficiency and the absence of
toxic atmosphere.
18.8.2 If it is necessary to gas-free and aerate
a hold space surrounding a type A cargo tank for routine inspection,
and flammable cargo is carried in the cargo tank, the inspection shall
be conducted when the tank contains only the minimum amount of cargo
"heel" to keep the cargo tank cold. The hold shall be re-inerted as
soon as the inspection is completed.
18.8.3 Personnel entering any space designated
as a hazardous area on a ship carrying flammable products shall not
introduce any potential source of ignition into the space, unless
it has been certified gas-free and is maintained in that condition.