154.1710—Exclusion of air from cargo tank vapor spaces.
When a vessel is carrying acetaldehyde, butadiene, ethylene oxide, or vinyl chloride, the master shall ensure that air is:
(a)
Purged from the cargo tanks and associated piping before the cargo is loaded; and
(b)
Excluded after the cargo is loaded by maintaining a positive pressure of at least 13.8 kPa gauge (2 psig) by:
(1)
Introducing a gas that:
(ii)
Is not flammable; and
(iii)
Does not contain more than 0.2% oxygen by volume; or
(2)
Controlling the cargo temperature.