International Code of Safety for Ships using Gases or other Low-flashpoint Fuels.
In practice
Engine-OEM and class-society support during commissioning. Operating procedures for LNG / methanol / ammonia fuel are vessel-specific. Crew receive STCW V/3 mandatory training.
Regulatory detail & full definition
International Code of Safety for Ships using Gases or other Low-flashpoint Fuels (MSC.391(95)) — the IMO mandatory code adopted in 2015 and effective 2017. The Code applies to ships using fuels with a flashpoint below 60 °C, principally LNG, LPG, methanol, and increasingly ammonia. It addresses fuel storage, distribution, consumer engines, ventilation, fire safety, electrical equipment, and crew training. The IGF Code requires Polar Code-style risk assessment for any fuel not covered by specific IGF rules — used to authorise methanol and ammonia fuelled new-builds before formal Code amendments were adopted.