Exam Question

### (b) Description of the Inert Gas (IG) System
#### Principle and Purpose
The Inert Gas (IG) System is a critical safety installation on oil tankers, designed to prevent explosions in cargo tanks. The primary principle is to reduce the oxygen content within the tank atmosphere to a level where combustion cannot be initiated or sustained. This is achieved by replacing the air in the tank with an inert gas, which is a gas mixture containing a low concentration of oxygen. SOLAS Chapter II-2, Regulation 4 requires tankers of 20,000 DWT and above (and certain others) to be fitted with a fixed IG system.
The system must be capable of rendering the tank atmosphere non-flammable (inert) and maintaining this condition throughout all cargo operations, including discharge, de-ballasting, and tank cleaning.