Inert gas system

An IGS, the equipment that fills a tanker’s cargo tanks with inert gas (flue gas or a generated nitrogen-rich stream) to hold the oxygen content below about 8 percent by volume, too lean to support combustion. SOLAS Chapter II-2 requires inert-gas protection on oil and chemical tankers above set sizes and, since the 2016 amendments, on new tankers of 8,000 dwt and above. Keeping tanks inert through loading, the laden voyage, discharge, and tank cleaning is the primary defense against a cargo-tank explosion.