Extended Operational and Trade Vocabulary

IMDG Code, Classes, Packing and Segregation glossary (page 2)

The dangerous-goods vocabulary anchored in the IMDG Code: the hazard classes, packing groups and provisions, segregation tables, the EmS fire and spill schedules, acceptance checks under IMDG 1.4, and on-deck accessibility for firefighting. Grounds each term in the IMDG Code provision that governs the carriage of packaged dangerous goods.

1120 defined terms.

Showing 250 on this page (page 2 of 5).

D

Department of Transportation: DOT, US authority that issues special permits and approvals harmonized with IMDG.
Depleted Uranium: Class 7 radioactive material with low specific activity, regulated under IMDG 2.7.
Description: See basic description, the formal IMDG sequence for naming a UN entry on documentation.
Desensitized Explosive: Explosive wetted, diluted or in solution to suppress detonation properties, often Class 4.1 or Class 3.
Detonation: Supersonic combustion wave used to characterize Class 1.1 substances.
Detonator: Device intended to initiate an explosive train, often UN 0030, 0255 or 0267 in Class 1.1B or 1.4B.
DGD: Dangerous Goods Declaration, shipper's signed statement of the hazardous nature and packaging of cargo.
DGDOC: Document of Compliance for the Carriage of Dangerous Goods under SOLAS II-2/19, issued to the ship by the flag administration.
Diborane: UN 1911, Class 2.3 with Class 2.1 subsidiary risk.
Diesel Fuel: UN 1202, Class 3 flammable liquid Packing Group III when flash point at or below 60 degrees Celsius.
Diethyl Ether: UN 1155, Class 3 flammable liquid Packing Group I.
Diethylamine: UN 1154, Class 3 with Class 8 subsidiary risk.
Difluoromethane: UN 3252, Class 2.1 flammable gas.
Diluent Type A: Organic liquid compatible with an organic peroxide and used to reduce concentration without lowering SADT excessively.
Diluent Type B: Organic liquid for diluting peroxides with boiling point at least 60 degrees Celsius above the SADT.
Dimethyl Sulfate: UN 1595, Class 6.1 with Class 8 subsidiary risk, Packing Group I.
Dimethyl Sulfide: UN 1164, Class 3 flammable liquid Packing Group II.
Dimethylamine Anhydrous: UN 1032, Class 2.1 flammable gas.
Dinitrogen Tetroxide: UN 1067, Class 2.3 toxic gas with Class 5.1 and 8 subsidiary risks.
Dioxane: UN 1165, Class 3 flammable liquid Packing Group II.
Diphenylmethyl Bromide: UN 1770, Class 8 corrosive solid.
Dipping Acid: Common industry term for mixed nitric and sulfuric acid, regulated as UN 1796 Class 8 with Class 5.1 subsidiary risk.
Direct Reduced Iron: DRI, regulated under IMSBC for bulk but referenced in IMDG segregation when Class 4.2 packaged forms apply.
Discharge: Operation of removing cargo from a CTU or vessel, subject to IMDG and CTU Code controls.
Disinfectant Liquid Corrosive NOS: UN 1903, Class 8.
Display Pyrotechnic: UN 0335, Class 1.3G fireworks for display.
Distance Apart Lengthwise: Segregation requirement in IMDG 7.2.4 for on deck container stowage measured as bay separation.
Distance Apart Transversely: Segregation distance across rows in on deck stowage, applied by container vessel software.
DNV: Det Norske Veritas (DNV); IACS member classification society.
Document of Compliance for Dangerous Goods: SOLAS II-2/19 certificate for ships carrying packaged dangerous goods.
Documentation: Set of records required under IMDG 5.4, including DGD, CPC, MSDS where required and approvals.
DOT-E: Old US Department of Transportation Exemption number, replaced by Special Permit DOT-SP.
DOT-SP: US Special Permit allowing alternative compliance, accepted under IMDG via mutual recognition where applicable.
Drilling Mud: Often not regulated unless containing dangerous components meeting IMDG classification thresholds.
Drum: Cylindrical part of a winch on which rope is wound.
Dry Cargo Ship: Vessel carrying packaged or bulk dry cargo, subject to SOLAS VII and IMDG for dangerous goods.
Dry Ice: UN 1845, Class 9, regulated for IMDG with provisions for ventilation and asphyxiation hazard control.
Dust Explosion: Combustion of suspended fine combustible dust (grain, coal, sulfur).
Dynamite: UN 0081 Class 1.1D explosive based on nitroglycerin.

E

EHS: Environmentally Hazardous Substance, generic UN entries 3077 solid and 3082 liquid for Class 9 EHS.
Electric Storage Battery Wet Filled with Acid: UN 2794, Class 8 corrosive.
Electric Storage Battery Wet Filled with Alkali: UN 2795, Class 8 corrosive.
Electric Storage Battery Wet Non Spillable: UN 2800, Class 8 corrosive with specific test criteria for non spillable design.
Electronic Detonator: UN 0511, 0512 or 0513 depending on subdivision, Class 1.4S/1.4B/1.1B.
Elevated Temperature Mark: Triangular thermometer mark required for substances transported at or above 100 degrees Celsius liquid or 240 degrees Celsius solid.
Elevated Temperature Substance: Substance covered by UN 3257 liquid or UN 3258 solid Class 9.
Empty Uncleaned Packaging: Packaging that previously contained dangerous goods and still retains residue, subject to IMDG provisions in 5.1.3.
EmS F-A: General fire schedule for non specific cargoes, used as a baseline.
EmS F-B: Fire schedule for flammable gases.
EmS F-C: Fire schedule for flammable liquids.
EmS F-D: Fire schedule for flammable solids and substances liable to spontaneous combustion.
EmS F-E: Fire schedule for substances which in contact with water emit flammable gases.
EmS F-F: Fire schedule for oxidizing substances.
EmS F-G: Fire schedule for organic peroxides.
EmS F-H: Fire schedule for radioactive material.
EmS F-I: Fire schedule for Class 1 explosives, Compatibility Group dependent.
EmS F-J: Fire schedule covering certain Class 4.1 self reactive substances.
EmS Guide: IMO Emergency Response Procedures for Ships Carrying Dangerous Goods, with fire schedules F-A to F-J and spill schedules S-A to S-Z.
EmS Number: Two reference codes printed in column 15 of the Dangerous Goods List, one fire and one spill schedule.
EmS S-A: General spill schedule for non specific cargoes.
EmS S-B: Spill schedule for toxic substances.
EmS S-C: Spill schedule for flammable liquids.
EmS S-D: Spill schedule for flammable solids.
EmS S-E: Spill schedule for spontaneously combustible substances.
EmS S-F: Spill schedule for substances reactive with water.
EmS S-G: Spill schedule for oxidizing substances.
EmS S-H: Spill schedule for organic peroxides.
EmS S-I: Spill schedule for radioactive material.
EmS S-J: Spill schedule for corrosive substances.
EmS S-N: Spill schedule for marine pollutants and other Class 9 entries.
Endothermic Substance: Substance whose decomposition absorbs heat, used in classifying some Class 4.1 entries.
Engineered Safety Feature: Design feature of Class 7 packages that limits release in accident, considered in package type assignment.
Environmentally Hazardous Substance Mark: Fish and tree pictogram required for marine pollutants on packages above 5 liters or 5 kilograms, except when meeting LQ provisions in certain cases.
EQ Mark: Excepted Quantity mark with class numbers and consignor or consignee initials.
Equivalence Provisions: IMDG 1.5 allowing competent authorities to authorize alternative arrangements with equivalent safety level.
Equivalent Safety: Standard for accepting non standard packagings or arrangements under IMDG 6.1.5.1.11.
Ethane: UN 1035, Class 2.1 flammable gas.
Ethanol: Class 3 flammable; carried in product or chemical tankers; needs dry tanks.
Ethanol Solution: UN 1170 covers solutions of ethanol in water above 24 percent by volume.
Ether: General term for organic compounds with R-O-R structure, many Class 3 such as diethyl ether UN 1155.
Ethyl Acetate: UN 1173, Class 3 flammable liquid Packing Group II.
Ethyl Acrylate Stabilized: UN 1917, Class 3 flammable liquid Packing Group II.
Ethyl Chloride: UN 1037, Class 2.1 flammable liquefied gas.
Ethyl Methyl Ether: UN 1039, Class 2.1 flammable gas.
Ethylene: Cargo on ethylene carriers at -104 C and slightly pressurized.
Ethylene Oxide: IBC Category Y; very reactive, special design ships.
Excepted Package: Class 7 package containing radioactive material within strict limits, requires UN number on documentation but no labels.
Excepted Quantity: EQ, very small quantity per package allowed with limited regulatory requirements per IMDG 3.5.
Excess Pressure: Pressure above atmospheric used to test pressure receptacles and IBCs.
Exhaust Ventilation: Ventilation arrangement that under IMDG 7.1 may be specified for certain stowage categories.
Existing Stocks: Phrase used in IMDG amendments to refer to pre printed packagings during transition periods.
Explosion Risk: Hazard property whose presence triggers Class 1 classification or subsidiary risk on certain Class 3 or 5.2 entries.
Explosive Article: Article containing explosive substance such as UN 0030 detonators electric.
Explosive Limits: Concentration range over which a flammable gas mixture in air will ignite, relevant to EmS guidance.
Explosive Substance: Substance classified under Class 1 by tests in the UN Manual of Tests and Criteria Part I.
External Pressure: Hydrostatic and hydrodynamic pressure on the hull governed by CSR-BC+OT Chapter 4.
Extinguishing Agent: Material used to suppress fire, with EmS specifying compatible agents per cargo class.
Eye Wash: First aid equipment required where corrosive Class 8 cargo is handled, referenced in MFAG.

F

F-A to F-J: Range of EmS fire schedules referenced in the Dangerous Goods List.
Factory Mutual: FM, US insurance research body issuing standards sometimes referenced in IMDG packaging approvals.
Faulty Lithium Battery: Battery shown to be defective for safety reasons under SP376; transport forbidden unless approved by competent authority.
Fertilizer Ammonium Nitrate Based: See UN 2067 and UN 2071 entries for IMDG classification.
Fiber Drum: Packaging code 1G, made of fiberboard with integral or non removable closure.
Fiberboard Box: Packaging code 4G, widely used outer for combination packagings.
Fiberboard Box with Inner Plastic Receptacles: Combination such as 4G/Y1.4/S where 4G is the outer.
Fillet weld: common weld type in crane fabrication.
Filling Density: Mass of liquefied gas per unit water capacity of receptacle, controlled under IMDG 4.2.
Filling Ratio: Ratio of liquid mass to water capacity of a portable tank for liquefied gases.
Fire detection system: Addressable fire alarm panel, SOLAS II-2 mandatory in machinery spaces.
Fire Hose: Required vessel firefighting equipment, length and pressure addressed in EmS planning.
Fire Main Pressure: Pressure of vessel firefighting main, important for combating dangerous goods cargo fires.
Fire Protection Drawings: Plans included in DGDOC indicating spaces approved for dangerous goods.
Fireworks: Class 1 articles such as UN 0333 to 0337 by division.
Fissile Material: Class 7 material containing fissile nuclides, with controls in IMDG 6.4 and 7.1 to prevent criticality.
Fittings: Components such as valves and pressure relief devices on tanks and cylinders, regulated under IMDG 6.7 and 6.8.
Flag State: State of the ship's nationality, with jurisdiction under UNCLOS Article 94.
Flammable Gas: Gas that meets criteria for ignition at low concentration in air, Class 2.1.
Flammable Liquid: Liquid with flash point at or below 60 degrees Celsius, Class 3.
Flammable Solid: Substance liable to cause fire through friction or fast burning, Class 4.1.
Flash point: Lowest temperature at which fuel vapor ignites with a pilot flame; minimum 60 C for SOLAS marine fuels (Pensky-Martens closed cup, ISO 2719).
Flexible Bulk Container: Container with flexible walls used for solid dangerous goods, type BK3 under IMDG 6.8.
Flexible IBC: Bag like IBC type 13H, used for certain solid dangerous goods.
Float Switch: Component in some tank designs relevant to ullage and overfill detection on portable tanks.
Flowable: Property of a substance to flow under conditions of carriage, distinguishing solid from semi solid for IMDG categorization.
FMC: US Federal Maritime Commission, regulator of ocean common carriers.
Foam: Firefighting medium with various compatibilities, EmS schedules specify suitable foam types.
Foam Concentrate: Substance mixed with water and air to form firefighting foam, vessel inventory considered for DG carriage.
Formaldehyde Solution Flammable: UN 1198, Class 3 with Class 8 subsidiary risk.
Formic Acid: UN 1779, Class 8 corrosive with Class 3 subsidiary risk.
Forwarder: Freight forwarder organising transport on behalf of shipper.
Fragments: Projection hazard considered for Class 1.2 articles.
Freight Container: Article of transport equipment of permanent character, see IMDG 1.2 definitions.
Freight Forwarder: See Forwarder.
Friction Sensitivity: Test under UN Manual of Tests and Criteria for Class 1 and self reactive Class 4.1 substances.
Frozen cargo: Product carried at -12 C or colder; common setpoints -18 C, -25 C, -29 C.
FTP Code: IMO International Code for Application of Fire Test Procedures, references material standards relevant to ship spaces holding dangerous goods.
Fuel Cell Cartridge: UN 3473 to 3479 by fuel type, with hazards spanning Class 3, 4.3, 8 and 2.

G

Gas Cartridge: UN 2037 non refillable receptacles for compressed or liquefied gas without release device.
Gas oil: Distillate fuel including MGO and DMA grades.
Gas Sample Non Pressurized Flammable NOS: UN 3167, Class 2.1 entry for non pressurized gas samples.
Gases Refrigerated Liquid NOS: UN 3158 oxidizing or other UN entries depending on properties.
Gasoline: High-vapor-pressure Class 3 cargo; static-electricity precautions.
Generic Entry: UN entry covering a chemical family such as UN 1992 Flammable Liquid Toxic NOS.
Generic Marking: Print or stamp on packaging indicating UN packaging code, packing group letter X, Y or Z, density and test pressure.
Genetically Modified Microorganism: UN 3245, Class 9 entry for GMMs not meeting Class 6.2 criteria.
Glass Inner Receptacle: Class of inner packagings used for sensitive Class 8 or 6.1 substances with quantity limits.
GMDSS: Global Maritime Distress and Safety System under SOLAS Chapter IV.
GMO: Genetically Modified Organism, UN 3245 Class 9 if meeting criteria.
Goggles: Personal protective equipment recommended by EmS spill schedules for handling Class 6.1 and Class 8 spillages.
GPS Coordinates: Location data sometimes recorded for casualties involving dangerous goods, relevant under MARPOL Annex III for marine pollutants.
Gradient: Slope at which a portable tank or vehicle may be parked, relevant to ullage and overflow under IMDG.
Granular Bagged: Form factor for bulk solids occasionally packaged in IBCs and bags under IMDG 6.5 and 6.6.
Gravity Discharge: Means of discharging contents of portable tanks, with valve design per IMDG 6.7.
Greenhouse Gas: Term not directly used in IMDG classification although some refrigerants such as UN 1078 are regulated as Class 2.2.
Gross mass: Total mass of container plus contents, the figure declared under SOLAS VGM.
Gross Tonnage: GT, measure of overall internal volume, determinant of statutory certification thresholds.

H

H2S: Hydrogen sulfide, UN 1053, Class 2.3 toxic gas with Class 2.1 subsidiary risk.
Halogenated Hydrocarbon: Family including UN 1846 carbon tetrachloride and UN 1888 chloroform under Class 6.1.
Halon Extinguishing System: Fire suppression installation phased out for new construction but historical IMDG fire schedules reference halon use.
Handling Label: Non hazard label such as orientation arrows, cargo aircraft only or this way up.
Hazard Class: One of nine IMDG classes derived from the UN Recommendations on the Transport of Dangerous Goods.
Hazard Code: Combination of class and subsidiary risk used in some national systems, derived from IMDG entries.
Hazard Identification Number: Kemler number used on ADR vehicle placards in Europe, not used in IMDG package marking.
Hazard Pictogram: Symbol on a class label, defined in IMDG 5.2.2.2 for each class.
Hazardous Cargo Hold: Vessel hold designed and certified for the carriage of packaged dangerous goods.
Hazardous Reaction: Reaction between two or more substances that could occur if segregation under IMDG 7.2 is not maintained.
HCl Solution: Hydrochloric acid solution, UN 1789, Class 8 corrosive.
Heat Source: Source of heat such as engine room bulkhead, segregation distance from heat sensitive cargo given by stowage codes such as SW2.
High Consequence Dangerous Goods: Subset of substances in IMDG 1.4.3.1 with potential for severe consequences if misused, with stricter security obligations.
High Speed Craft: Vessels regulated under the HSC Code, with restrictions on dangerous goods carriage.
HMX Wetted: See cyclotetramethylene tetranitramine entries.
Holds: Vessel cargo compartments, with IMDG stowage categories A, B and D allowing under deck stowage.
Hopper Container: Container with bottom discharge, used for some IMSBC and occasionally IMDG bulk solids.
Hospital Waste: UN 3291, Class 6.2 clinical waste, regulated waste subject to IMDG.
HSC Code: International Code of Safety for High-Speed Craft, MSC.97(73), 2000.
Hydraulic Test: Pressure test using water to verify tank or pipe integrity.
Hydrazine Anhydrous: UN 2029, Class 8 with Class 3 and 6.1 subsidiary risks.
Hydrochloric Acid Solution: UN 1789, Class 8 corrosive liquid Packing Group II or III by concentration.
Hydrofluoric Acid Anhydrous: UN 1052, Class 8 corrosive with Class 6.1 subsidiary risk, Packing Group I.
Hydrofluoric Acid Solution: UN 1790, Class 8 corrosive with Class 6.1 subsidiary risk.
Hydrogen Compressed: UN 1049, Class 2.1 flammable gas.
Hydrogen Cyanide Stabilized: UN 1051, Class 6.1 with Class 3 subsidiary risk, Packing Group I.
Hydrogen Fluoride: UN 1052, see hydrofluoric acid anhydrous.
Hydrogen Peroxide Aqueous Solution: UN 2014 above 20 percent and not more than 60 percent, Class 5.1 with Class 8 subsidiary risk.
Hydrogen Peroxide Aqueous Solution Stabilized: UN 2015 above 60 percent, Class 5.1 with Class 8 subsidiary risk, Packing Group I.
Hydrogen Sulfide Liquefied: UN 1053, see H2S entry.
Hypergolic: Property of substances that ignite on contact, considered in special provisions for oxidizers and fuels.

I

IAEA Regulations: IAEA SSR-6 Regulations for the Safe Transport of Radioactive Material, basis for IMDG Class 7 provisions.
IATA DGR: IATA Dangerous Goods Regulations, the air industry interpretation of ICAO Technical Instructions, parallel to IMDG.
IBC: Intermediate Bulk Container, packaging up to 3 cubic meters with codes such as 11A steel, 31H1 rigid plastic, 13H flexible.
IBC Code: International Code for the Construction and Equipment of Ships Carrying Dangerous Chemicals in Bulk.
ICAO Technical Instructions: Civil aviation dangerous goods instructions, the legally binding parallel to IMDG for air transport.
ICC: Institute Cargo Clauses A, B, and C.
Ignition Source: Source capable of igniting a flammable atmosphere, controlled by segregation codes such as SW1 protected from sources of heat.
Ignition Temperature: Minimum temperature at which a substance ignites without external flame, considered for Class 4.2 self heating tests.
IMDG Code: International Maritime Dangerous Goods Code, mandatory under SOLAS VII Part A.
IMDG Code Amendment 39-18: Edition mandatory from 1 January 2020.
IMDG Code Amendment 40-20: Edition mandatory from 1 June 2022 after the voluntary period from 1 January 2021.
IMDG Code Amendment 41-22: Current edition mandatory from 1 January 2024 after voluntary application from 1 January 2023.
IMDG Code Compliance Officer: Internal company role responsible for ensuring IMDG and related code compliance.
IMDG Code Edition: Consolidated text including the most recent amendment, published biennially in odd years by IMO.
IMDG Code Supplement: Companion publication containing EmS, MFAG and reporting procedures.
IMO: International Maritime Organization, UN specialized agency for shipping safety, security, and pollution prevention.
IMO Type 1 Portable Tank: Tank with minimum design pressure 1.75 bar, used for severe Class 3, 6.1 and 8 substances.
IMO Type 2 Portable Tank: Tank with minimum design pressure 1.0 bar, for less hazardous Class 3 and 8 substances.
IMO Type 5 Portable Tank: Tank for non refrigerated liquefied gases, predecessor to UN portable tank instructions T50.
IMO Type 7 Portable Tank: Tank for refrigerated liquefied gases, predecessor to UN T75 portable tank instruction.
IMSBC Code: International Maritime Solid Bulk Cargoes Code, mandatory under SOLAS VI/1-1 and VII/7-1.
Incident Reporting: SOLAS VII regulation 7 1 and MARPOL Annex III obligations to report dangerous goods incidents.
Incompatibility: Property of two substances to react dangerously, addressed by IMDG segregation provisions.
Inert gas: nitrogen or flue gas blanketing chemical or oil tanks during transfer.
Infectious Substance: Class 6.2 substance containing pathogens capable of causing disease.
Infectious Substance Affecting Animals Only: UN 2900, Class 6.2 Category A.
Infectious Substance Affecting Humans: UN 2814, Class 6.2 Category A.
Inhalation Toxicity: Hazard property used to assign Class 6.1 packing groups via LC50 values for dust, mist and vapor.
Inner Packaging: Receptacle inside a combination packaging that contains the dangerous goods directly.
Inner Receptacle: Component of a composite packaging that contains the contents and is rigidly retained by the outer.
Inorganic Peroxides: Such as UN 1483 magnesium peroxide, Class 5.1 oxidizer.
Inspection Body: Body authorized by competent authority to inspect and approve IMDG packagings and portable tanks.
Inspection Plate: Identification plate on portable tanks bearing approval details under IMDG 6.7.
Instruction in Writing: Driver instructions used under ADR, not directly an IMDG document but linked at intermodal interfaces.
Intactness: Required state of packagings and CTUs offered for IMDG carriage, see CPC requirements.
Intermediate Bulk Container: See IBC.
Intermediate Packaging: Packaging placed between inner and outer packagings, code such as 4D in some combinations.
Intermodal Tank: ISO frame portable tank designed for road, rail and sea transport under IMDG Chapter 6.7.
International Convention for the Safety of Life at Sea: SOLAS, Chapter VII gives IMDG its mandatory legal status.
International Tank Container Organisation: ITCO, industry association whose practices align tank container operations with IMDG.
Interpretation: Authoritative clarification of IMDG provisions by IMO sub committees, often via CCC circulars.
ISO 1496: ISO standard for container specifications and testing.
ISO 668: ISO standard for container classifications and dimensions.
ISO Tank: Common industry term for a UN portable tank built to ISO 1496/3.
Isocyanate: Reactive group in polyurethane Component B providing crosslinking.

J

Jerrican: Rectangular metal or plastic packaging, codes 3A1, 3A2, 3B1, 3B2, 3H1, 3H2.
Joint Stowage: Stowage of multiple items secured as one block.

K

Keep Cool: Stowage code SW2 protected from sources of heat, ensuring temperature stability for sensitive cargo.
Kemler Code: Two or three digit hazard identification number on ADR road placards; not used on IMDG packages.
Kerosene: Refined distillate; Class 3 flammable.
Krypton Compressed: UN 1056, Class 2.2 non flammable non toxic gas.

L

Labels: Square on point hazard diamonds of side length 100 mm required on each package containing dangerous goods.
Lacquer: Single-pack solvent-evaporating coating, used historically for furniture and decorative trim and rarely for hull work.
Lambda Cyhalothrin: Pesticide active ingredient that often classifies as UN 3349 Class 6.1.
Large Packaging: Packaging with mass over 400 kg or capacity over 450 liters but not more than 3 cubic meters, codes 50A and similar under IMDG 6.6.
Large Salvage Packaging: Packaging used to recover damaged dangerous goods packages, code 50AS under IMDG 6.6.
LC50: Lethal concentration killing 50 percent of test population, criterion for Class 6.1 and 2.3 classification.
LD50: Lethal dose killing 50 percent of test population, criterion for oral and dermal toxicity in Class 6.1.
Leakproofness Test: Pressure test required on certain liquid packagings under IMDG 6.1.5.4.
Lethal Inhalation Concentration: See LC50.
Lifting Test: Test for IBCs and large packagings under IMDG 6.5 and 6.6 to demonstrate integrity when handled.
Limited Quantities: LQ, small quantity per inner packaging exemption regime under IMDG Chapter 3.4.
Limited Quantity Mark: Square on point mark with white center and black border, replacing class labels for LQ shipments.