IGC Code
International Code for the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk — mandatory requirements for gas carrier design, construction and equipment.
Adopted
1983
Mandatory
1 Jul 1986
Legal Basis
SOLAS VII-C
Covers
LNG, LPG, NGL
Scope & Application
The IGC Code applies to gas carriers (ships constructed for and used in the carriage of liquefied gases in bulk) built on or after 1 July 1986. It covers design and construction, cargo containment, cargo transfer, materials, ventilation, personnel protection, fire safety, mechanical, piping and process pressure vessels, electrical installations and operational requirements.
The code recognizes that gas carriers present special hazards due to the flammability, toxicity, reactivity, or low temperature characteristics of the liquefied gas cargoes they carry.
Cargo Containment System Types
Type A Independent Tank
Primarily flat surfaces. Design vapor pressure not exceeding 0.025 MPa. Requires a full secondary barrier (inner hull acts as barrier). Used mainly for fully refrigerated tanks.
Examples: Kvaerner Moss type A
Type B Independent Tank
Usually of prismatic or spherical design. Can be designed to a maximum vapor pressure of 0.025 MPa. Requires a partial secondary barrier only, due to advanced stress and fatigue analysis.
Examples: Moss spherical tanks, IHI SPB
Type C Independent Tank
Pressure vessel type. Can carry cargo at above 0.025 MPa. No secondary barrier required. Used for high-pressure LPG/ethylene.
Examples: Semi-refrigerated LPG tankers
Integral Tank
Part of the ship's hull structure — structural members form the tank. Use essentially restricted to low vapor pressure cargoes. Not common for LNG.
Examples: Some LPG carriers
Membrane Tank
Non-self-supporting thin membrane supported by ship structure. Vacuum-insulated with perlite/glass fiber insulation between membrane and hull. Requires full secondary barrier.
Examples: Gaztransport (GTT) No. 96, Mark III
Certificates
International Certificate of Fitness for the Carriage of Liquefied Gases in Bulk
Validity: 5 years · Gas carriers built after 1 Jul 1986
Certificate of Fitness for the Carriage of Liquefied Gases in Bulk (GC Code)
Validity: 5 years · Gas carriers built 31 Oct 1976 – 1 Jul 1986
Covered Cargoes
Ship Types
Highest hazard — specific location requirements
Significant hazard cargo
Type C tanks — pressure vessels
Low hazard cargo — most LPG carriers