'C' Class divisions are bulkheads, decks, ceilings and linings constructed of approved non-combustible materials, which have no requirements relative to the passage of smoke and flame nor the limiting of temperature rise.
All external openings are to be kept closed when a tanker cargo operations is underway.
Ventilation inlets for the spaces are to be located as far as practicable from gas dangerous zones.
Also to prevent the entry of the cargo vapour in to the accommodation spaces and engine room spaces, these areas are kept pressurized by suitably arranging the ventilation.