What is the primary function of an Inert Gas System on a tanker?

The primary function of an Inert Gas System (IGS) on a tanker is to prevent explosions from flammable vapors. Inert gas is produced by burning a portion of the fuel oil from the vessel's main engine and then filtering and cooling it before it's introduced into the cargo tanks. This process replaces the oxygen in the cargo tanks with inert gas, creating an atmosphere that is incapable of supporting combustion.

By minimizing the presence of oxygen, the risk of fire or explosion due to flammable vapors is significantly reduced during cargo operations. This safety measure is critical in ensuring the ship's and crew's safety, as well as protecting the environment from potential spills or accidents.

The other options, while relating to cargo operations, do not accurately represent the core function of an Inert Gas System. Loading time, cargo heating, and emergency discharge are important aspects of tanker operation, but they are not the primary focus of the inert gas system, which is fundamentally about safety concerning flammable risks.