What is the maximum allowable oxygen content in ship's cargo tanks, inert gas piping, and the vapor recovery system?

In the context of tanker operations, particularly involving the transport of volatile cargoes, maintaining low levels of oxygen within the cargo tanks, inert gas piping, and vapor recovery systems is critical for safety and to prevent the risk of fire or explosion. The maximum allowable oxygen content established by international regulations, such as those provided by the International Maritime Organization (IMO) and the International Chamber of Shipping (ICS), is set at 8%. This standard ensures that the atmosphere in these systems is inerted adequately to minimize flammability.

While maintaining oxygen levels below this threshold, tankers can significantly reduce the potential for ignition and enhance the safety of operations. Levels exceeding this amount may increase the risk of combustion in the presence of flammable vapors. Therefore, an oxygen content of up to 8% is accepted as the maximum limit that balances safety while still allowing for operational flexibility in handling cargoes.