Extended Operational and Trade Vocabulary

IMDG Code: Classes, Divisions, Segregation, and Key UN Numbers glossary

Terminology of the IMDG Code for dangerous goods at sea: hazard classes and divisions, key UN numbers such as aerosols UN 1950 and ammonium nitrate UN 1942, the amendment cycle adopted by IMO resolutions like MSC.501(105) and MSC.532(107), recognised classification societies, and the segregation and stowage rules governing packaged dangerous cargo.

344 defined terms.

Showing 250 on this page (page 1 of 2).

A

Acute Toxicity Criteria: The LD50 oral, LD50 dermal, and LC50 inhalation thresholds in 2.6.2.2 used to assign Class 6.1 packing groups.
Aerosol Dispenser: A non-refillable receptacle meeting 6.2.4 requirements, distinguished from gas cartridges UN 2037 by design.
Aerosols UN 1950: Non-refillable receptacles containing compressed, liquefied, or dissolved gas with or without a liquid, paste, or powder, assigned to Class 2 with subsidiary risks based on contents.
Alcoholic Beverages: UN 3065, Class 3 flammable liquid with concessions for retail packagings above stated alcohol content.
Allowed Mixed Loading: Combinations of explosives compatibility groups permitted together per Table 7.2.7.1.4 (e.g., 1.4S with most other groups).
Amendment 41-22: The IMDG Code amendment adopted by IMO Resolution MSC.501(105), in force on a voluntary basis from 1 January 2023 and mandatory from 1 January 2024.
Amendment 42-24: The IMDG Code amendment adopted by IMO Resolution MSC.532(107), applicable voluntarily from 1 January 2025 and mandatory from 1 January 2026.
Amines Liquid Corrosive NOS UN 2735: A Class 8 generic entry for liquid amines or polyamines that are corrosive, assigned PG I, II, or III based on skin corrosion data.
Ammonium Nitrate UN 1942: An oxidiser (Class 5.1) with not more than 0.2 per cent combustible substances, requiring specific stowage and segregation from organic materials.
Approved Classification Society: A recognised organisation authorised by the flag State to issue CSC plates and approve packagings under the IMDG Code framework.
Articles Pressurized UN 3164: Articles such as shock absorbers or gas struts charged with a non-flammable gas, classified in Class 2.2 with specific construction tests.
Articulated Tank Vehicles: Road vehicles carrying portable tanks or tank containers; subject to packing certificate requirements identical to freight containers under 5.4.2.
Ash Residue (Stowage): Reference for organic peroxides where residues must be segregated to avoid catalytic decomposition; relevant to Class 5.2 stowage planning.
Asphyxiant Gas: Subsidiary characteristic of Class 2.2 gases such as nitrogen UN 1066 that displace oxygen in enclosed spaces.
Authorized Packaging: Packaging that bears valid UN specification marks and conforms to Chapter 6.1, 6.3, 6.5, or 6.6 test reports.
Away From (Segregation Code 1): Segregation requirement in Table 7.2.4 meaning effectively segregated so incompatible goods cannot interact dangerously but may be stowed in the same compartment or hold, provided a minimum…

B

Bilge Pumping: Removal of accumulated water from machinery and cargo spaces during refloating operations.
Biological Substance Category B UN 3373: A Class 6.2 entry for infectious substances not meeting Category A criteria, transported under packing instruction P650.
Blue Label (Class 4.3): The Class 4.3 hazard label depicting a flame on a blue background, indicating substances dangerous when wet that emit flammable gases on contact with water.
Bonded Warehouse Procedures: Customs procedures referenced in the IMDG Code 7.1 stowage planning when goods transit ports without entering free circulation.
Booster Explosives: Class 1 articles such as UN 0042 boosters without detonator, generally Division 1.1D, requiring magazine stowage.
Bottom Up Stowage (Class 1): Stowage requirement for explosives where heavier packages are placed below lighter packages to prevent crushing of detonators.
Bromates Inorganic Aqueous Solution NOS UN 3213: A Class 5.1 oxidiser entry for inorganic bromate solutions.
Bromine UN 1744: A Class 8 corrosive liquid with subsidiary risk 6.1, packing group I, requiring special carriage in glass or PTFE-lined steel.
Bulk Container: IBC, freight container or portable tank used for dangerous goods in bulk, with IMDG types BK1, BK2, BK3 for solids.
Bulkhead: Vertical partition dividing a ship into compartments.
Bunker Fuel: Heavy residual fuel typically not regulated by IMDG unless flashpoint criteria for UN 3082 or UN 1993 are met.
Butane UN 1011: A Class 2.1 flammable liquefied gas commonly shipped in pressurised cylinders or under refrigeration.

C

Cargo Information: Shipper-declared particulars required under SOLAS VI/2.
Class 1 Explosives: IMDG Class 1 with compatibility groups A-S.
Class 2 Gases: 2.1 flammable, 2.2 non-flammable non-toxic, 2.3 toxic.
Class 3 Flammable Liquids: Flashpoint at or below 60 C.
Class 4.1 Flammable Solids: Readily combustible solids, self-reactive substances, polymerising substances, and solid desensitised explosives.
Class 4.2 Spontaneously Combustible: Substances liable to spontaneous heating under normal conditions or to heating in contact with air, then liable to catch fire.
Class 4.3 Dangerous When Wet: Substances which, by interaction with water, evolve flammable gases at a rate greater than 1 L per kg per hour.
Class 5.1 Oxidizing Substances: Substances that, while not necessarily combustible, may cause or contribute to the combustion of other material, generally by yielding oxygen.
Class 5.2 Organic Peroxides: Thermally unstable organic substances containing the bivalent -O-O- structure, classified Type A through Type G based on the SADT test and detonation/deflagration behaviour.
Class 6.1 Toxic Substances: Substances liable to cause death, injury, or harm to human health if swallowed, inhaled, or by skin contact.
Class 6.2 Infectious Substances: Substances known or reasonably expected to contain pathogens, split into Category A (UN 2814/2900) and Category B (UN 3373).
Class 7 Radioactive Material: Material with specific activity exceeding 70 Bq/g for which both activity concentration and total activity exceed the values in Table 2.7.2.2.1.
Class 8 Corrosive Substances: Substances that by chemical action cause severe damage when in contact with living tissue or, in the case of leakage, will materially damage other goods or means of transport.
Class 9 Miscellaneous: Substances and articles that present a danger not covered by other classes, including lithium batteries, marine pollutants, magnetised material, and elevated temperature substances.
Class Cross-Reference Index: The alphabetical and numerical index in Volume 2 mapping common names to UN numbers.
Closed Cup Flashpoint: The flashpoint determined by Abel, Pensky-Martens, or Tag closed-cup apparatus per 2.3.3.
Combination Packaging: Packaging composed of one or more inner packagings secured in an outer packaging, IMDG code combinations such as 4G/Y15/S.
Compatibility Group A: Primary explosive substance, e.g., UN 0074 diazodinitrophenol wetted.
Compatibility Group B: Article containing a primary explosive substance with fewer than two effective protective features.
Compatibility Group C: Propellant explosive substance or other deflagrating explosive or article containing such, e.g., single-base propellant.
Compatibility Group D: Secondary detonating explosive substance or black powder or article containing a secondary detonating explosive substance without means of initiation.
Compatibility Group E: Article containing a secondary detonating explosive substance with means of initiation, without propelling charge.
Compatibility Group F: Article containing secondary detonating explosive substance with its means of initiation and a propelling charge or without a propelling charge.
Compatibility Group G: Pyrotechnic substance or article containing a pyrotechnic substance, e.g., signal flares UN 0093.
Compatibility Group H: Article containing both an explosive substance and white phosphorus.
Compatibility Group J: Article containing both an explosive substance and flammable liquid or gel.
Compatibility Group K: Article containing both an explosive substance and a toxic chemical agent.
Compatibility Group L: Explosive substance or article containing a substance presenting a special risk needing isolation, e.g., damaged or suspect goods.
Compatibility Group N: Articles containing only extremely insensitive detonating substances.
Compatibility Group S: Substance or article so packed or designed that any hazardous effects arising from accidental functioning are confined within the package, e.g., 1.4S consumer fireworks.
Compatibility Table: Table 7.2.7.1.4 listing permissible mixed stowage of Class 1 compatibility groups.
Compressed Gas NOS UN 1956: A Class 2.2 not otherwise specified entry for non-flammable, non-toxic compressed gases.
Consignment: One or more packages of dangerous goods presented by a consignor for transport.
Container Packing Certificate: CPC, declaration signed by the person responsible for packing a container that IMDG packing requirements are met.
Contamination Non-fixed: Class 7 surface contamination removable under routine conditions, with limits in 2.7.1.2.
Critical Temperature: For Class 2 refrigerated liquefied gases, the temperature above which the substance cannot exist as a liquid.
Crude Oil UN 1267: A Class 3 flammable liquid covering petroleum crude oil, with packing group I, II, or III depending on initial boiling point and flashpoint.
CSC Plate: Container Safety Convention safety approval plate; verified on container surveys.
CTU Code: IMO/ILO/UNECE Code of Practice for Packing of Cargo Transport Units.

D

Damaged Package: A package showing leakage, damage, or contamination that may not be loaded; must be repacked into salvage packaging.
Dangerous Goods Declaration (DGD): Shipper's certified document under IMDG.
Dangerous Goods List (DGL): Main IMDG table by UN number with packing/segregation columns.
Dangerous Goods Manifest: Required under SOLAS VII/4.
Deck cargo: Cargo carried on the weather deck.
Decomposition Temperature: Temperature reference for self-reactive Class 4.1 and organic peroxide Class 5.2 substances requiring temperature control.
Deflagration: Subsonic combustion wave; relevant to dust and vapor explosions.
Desensitised Explosives: Substances under UN 3379 (liquid) and UN 3380 (solid) that are wetted or diluted to suppress explosive properties; assigned to Class 4.1.
Detonator Assemblies UN 0360/0361/0500: Class 1 articles in Compatibility Group B or S depending on construction and confinement.
Diesel Fuel UN 1202: A Class 3 flammable liquid, packing group III, with flashpoint above 60 deg C but historically reclassified as PG III where flashpoint is above 60 deg C and not exceeding 100 deg C if regulated as DG.
Division 1.1: Substances and articles that have a mass explosion hazard, in which virtually the entire load is affected almost instantaneously.
Division 1.2: Substances and articles that have a projection hazard but not a mass explosion hazard.
Division 1.3: Substances and articles that have a fire hazard and either a minor blast hazard or a minor projection hazard.
Division 1.4: Substances and articles that present no significant hazard; effects are largely confined to the package, with 1.4S permitted without further restriction.
Division 1.5: Very insensitive substances that have a mass explosion hazard but are so insensitive that there is very little probability of initiation, e.g., UN 0331 blasting agent type B.
Division 1.6: Extremely insensitive articles which do not have a mass explosion hazard, containing only extremely insensitive detonating substances.
Document of Compliance (DOC): Issued to companies under ISM Code.
DOT-39 Cylinder: A non-refillable U.S. cylinder design; not a UN spec packaging, generally unacceptable for international IMDG shipments without specific authorisation.
Drum (1A1, 1A2, 1B1, 1B2, 1D, 1G, 1H1, 1H2, 1N1, 1N2): UN specification packaging codes for steel non-removable head (1A1), steel removable head (1A2), aluminium drums, plywood, fibre, plastics, and other metal drums.
Dual-Use Goods: Items with civilian and military applications subject to export control.

E

Elevated Temperature Substance: Substance covered by UN 3257 liquid or UN 3258 solid Class 9.
Emergency Contact: A 24-hour telephone number required by some authorities on the dangerous goods declaration.
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 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-K: Spillage schedule for highly toxic substances.
EmS S-L: Spillage schedule for radioactive material.
EmS S-M: Spillage schedule for marine pollutants.
EmS S-N: Spill schedule for marine pollutants and other Class 9 entries.
EmS S-O: Spillage schedule for corrosive substances Class 8.
EmS S-P: Spillage schedule for highly volatile flammable liquids.
EmS S-Q: Spillage schedule for substances polymerising on contact.
EmS S-R: Spillage schedule for elevated temperature substances.
EmS S-S: Spillage schedule for environmentally hazardous substances.
EmS S-T: Spillage schedule for lithium batteries and battery powered devices.
EmS S-U: Spillage schedule for self-reactive substances.
EmS S-V: Spillage schedule for water-reactive solids generating toxic gas.
EmS S-W: Spillage schedule for corrosive substances with subsidiary risk.
EmS S-X: Spillage schedule for desensitised explosives.
EmS S-Y: Spillage schedule for substances with multiple subsidiary risks.
EmS S-Z: Spillage schedule for miscellaneous Class 9 substances not elsewhere covered.
Environmentally Hazardous Substance Criteria: Acute aquatic toxicity Category 1, chronic Category 1 or 2 per GHS, used to flag marine pollutants.
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.
Ethanol UN 1170: A Class 3 flammable liquid, with packing group II for solutions and packing group III for aqueous solutions above 24 per cent and below 70 per cent ethanol depending on flashpoint.
EU Class 3 PG III Flashpoint Range: 23 deg C to 60 deg C inclusive in EU classification; IMDG aligns generally for sea transport.
Excepted Package: Class 7 package containing radioactive material within strict limits, requires UN number on documentation but no labels.
Excepted Quantity (EQ): Provisions in Chapter 3.5 allowing very small quantities per inner and outer packaging (E0 to E5) with reduced documentation.

F

Fissile Material: Class 7 material containing fissile nuclides, with controls in IMDG 6.4 and 7.1 to prevent criticality.
Fixed Contamination: Class 7 surface contamination not removable under routine conditions, with separate limits in 2.7.1.2.
Flashpoint: Temperature at which a liquid releases enough vapor to ignite; key to IMDG/MARPOL.
Flexible IBC: Bag like IBC type 13H, used for certain solid dangerous goods.
Forbidden Substances: Substances listed in 3.1.2.8.1 or as "FORBIDDEN" in column 3 of the DGL, such as certain organic peroxide Type A formulations.
Freight Container: Article of transport equipment of permanent character, see IMDG 1.2 definitions.
Fuel Cell Cartridges UN 3473-3479: Class 3, 4.3, or 8 articles depending on the contained substance, with specific carriage provisions.
Fumigated Cargo Transport Unit UN 3359: A Class 9 entry covering CTUs under active fumigation with a phosphine or methyl bromide residue, requiring the fumigation warning sign.
Fumigation Warning Sign: The rectangular sign with the word "FUMIGATION WARNING" and details per 5.5.2.3.

G

Gasoline UN 1203: Motor spirit including blended motor spirit, Class 3, packing group II.
Genetically Modified Microorganisms UN 3245: Microorganisms not meeting Category A or B but capable of altering animals, plants, or biological substances, assigned to Class 9.
Green Label (Class 2.2): Non-flammable non-toxic gas label with the gas cylinder symbol on green background.
Group of Packing: An obsolete term superseded by Packing Group; PG I high danger, PG II medium, PG III low.

H

Hazard Class: One of nine IMDG classes derived from the UN Recommendations on the Transport of Dangerous Goods.
Hazard Identification Number: Kemler number used on ADR vehicle placards in Europe, not used in IMDG package marking.
Heating Devices in CTUs: Permitted only when the substance temperature is controlled and equipment is certified, per 5.5.3 dry ice and refrigerated substances.
High Consequence Dangerous Goods (HCDG): Goods identified in 1.4.3 as potentially attractive for terrorist misuse, e.g., Division 1.1 above 50 kg, Class 6.2 Category A, and Class 7 of Type B(M)/C.
Hydrochloric Acid UN 1789: A Class 8 corrosive liquid, with packing group II at greater than 25 per cent HCl and packing group III otherwise.
Hydrogen Peroxide UN 2014: Aqueous solutions with 20 to 60 per cent H2O2 stabilised, Class 5.1 with subsidiary risk 8, packing group II.
Hypochlorite Solution UN 1791: A Class 8 corrosive liquid covering bleach solutions; packing group II or III based on available chlorine.

I

IBC: Intermediate Bulk Container, packaging up to 3 cubic meters with codes such as 11A steel, 31H1 rigid plastic, 13H flexible.
IMSBC Code: International Maritime Solid Bulk Cargoes Code, mandatory under SOLAS VI/1-1 and VII/7-1.
Industrial Package IP-1: Class 7 package providing the lowest containment level for low specific activity material and surface contaminated objects.
Industrial Package IP-2: Class 7 package that must withstand the free drop and stacking tests in 6.4.15.
Industrial Package IP-3: Class 7 package meeting all Type A package tests except as relaxed.
INF Code: International Code for the Safe Carriage of Packaged Irradiated Nuclear Fuel, mandatory under SOLAS VII.
Infectious Substance Affecting Animals UN 2900: Category A animal pathogen, packaged to P620.
Infectious Substance Affecting Humans UN 2814: Category A pathogen capable of causing permanent disability, life-threatening, or fatal disease in humans, packaged to P620.
Inhalation Hazard Zone A through D: Subdivision of Class 6.1 Packing Group I gases and vapours based on LC50 by inhalation.
Inner Packaging: Receptacle inside a combination packaging that contains the dangerous goods directly.
Intermediate Bulk Container Codes: 11A composite IBC, 13H plastics flexible, 31A metal liquid, 31H rigid plastics liquid, etc.

J

Jerrican (3A1, 3A2, 3B1, 3B2, 3H1, 3H2): UN spec packaging code for steel and plastics jerricans up to 60 L capacity.
Joint Stowage: Stowage of multiple items secured as one block.

K

Keep Away from Heat: Mandatory orientation/handling text for temperature-sensitive Class 5.2 self-reactive Type C and D substances.
Kerosene UN 1223: A Class 3 flammable liquid, packing group III with flashpoint between 38 deg C and 60 deg C.

L

Label: A diamond-shaped (square-on-point) primary or subsidiary hazard marking of at least 100 mm x 100 mm on packages per 5.2.2.
Limited Quantity (LQ): Provisions in Chapter 3.4 allowing relaxed packaging for inner packagings up to 1 L or 1 kg combined with outer packaging up to 30 kg gross.
Limited Quantity Air Mark: A square-on-point with the letter "Y" superimposed on the centre, indicating limited quantity acceptable for air transport.
Limited Quantity Mark: Square on point mark with white center and black border, replacing class labels for LQ shipments.
Liquefied Natural Gas UN 1972: Methane refrigerated liquid or natural gas refrigerated liquid with high methane content, Class 2.1.
Liquefied Petroleum Gas UN 1075: LPG, a Class 2.1 flammable gas mixture of propane, butane, and other hydrocarbons.
Lithium Battery Mark: Rectangular mark with black border, UN number text, hazard symbol and contact phone number, required for many UN 3480, 3481, 3090, 3091 consignments.
Lithium Battery Test Summary: A document required from 2020 per 2.9.4 confirming each cell and battery type meets UN Manual of Tests and Criteria Part III Section 38.3.
Lithium Metal Batteries Contained in Equipment UN 3091: Class 9 lithium metal batteries packed with or contained in equipment.
Lithium Metal Batteries UN 3090: Class 9 lithium metal or lithium alloy batteries shipped alone, with specific load and packaging provisions.
Lithium-ion Batteries Contained in Equipment UN 3481: Class 9 batteries packed with or contained in equipment.
Lithium-ion Batteries UN 3480: Class 9 batteries without equipment, with watt-hour rating marked; subject to special provision 188, 230, 348, and lithium battery test summary requirements.
Low Specific Activity (LSA): LSA-I, LSA-II, LSA-III subcategories of Class 7 material with limited specific activity per gram.

M

Marine Pollutant: IMDG marking for substances harmful to marine environment.
Marine Pollutant Mark: Pictogram of fish and tree on packages, freight containers and tank containers carrying marine pollutants.
MARPOL Annex III: Prevention of pollution by harmful substances in packaged form.
MARPOL Convention: Annex III implements IMDG marine pollutant identification and reporting on a treaty basis.
MFAG: Medical First Aid Guide for Use in Accidents Involving Dangerous Goods; IMO publication supplementing IMDG Code.
MFAG Tables: Numbered tables 100s through 700s covering chemical agent treatments, antidotes, observation periods, and contact information.
MSC.1/Circ.1497: CTU Code.
Multimodal Dangerous Goods Form: MDGF.
Multiple Hazard Precedence: Precedence rules in 2.0.3 determining the primary class when a substance meets criteria for more than one class.

N

N.O.S. Entry: A "Not Otherwise Specified" generic entry in the DGL requiring the technical name in parentheses after the PSN per special provision 274.
Net Explosive Mass (NEM): The total mass of the explosive substance without packaging, used for Class 1 stowage and segregation calculations.
Nitric Acid UN 2031: A Class 8 corrosive liquid with subsidiary risk 5.1 above 65 per cent; below 65 per cent it is PG II straight Class 8.
Nitrogen Refrigerated Liquid UN 1977: A Class 2.2 deeply refrigerated cryogenic liquid with asphyxiant properties.
Non-bulk Packaging: Packaging with a capacity of 450 L or less or net mass of 400 kg or less for solids.
NOS Technical Name Requirement: Per SP 274, the technical name shall appear in parentheses after the PSN.

O

Orange Hazard Label Background (Class 1): Per 5.2.2.2 the explosives label background is orange.
Orange Label (Class 1): Background colour for primary hazard labels of Division 1.1, 1.2, 1.3, 1.4, 1.5, and 1.6 explosives.
Orientation Arrows: Black or red arrows on two opposing vertical sides indicating upright orientation for liquid inner packagings.
Outer Packaging: Outermost protective component of a combination packaging.
Overpack: Enclosure used by a single consignor to consolidate one or more packages into one unit for handling.
Overpack Mark: The word "OVERPACK" in letters at least 12 mm high, per 5.1.2.1.1.
Oxidising Substance (5.1): Substance assigned to Class 5.1 based on the burn time test in UN Manual of Tests and Criteria Test O.1 or O.2 (solids) or O.3 (liquids).
Oxygen Refrigerated Liquid UN 1073: A Class 2.2 cryogenic liquid with subsidiary risk 5.1 due to oxidising properties.

P

Packing certificate: CTU Code packing certificate.
Packing Group I: Substances presenting high danger requiring the most robust UN packaging marked X.
Packing Group II: Substances presenting medium danger requiring UN packaging marked Y or X.
Packing Group III: Substances presenting low danger requiring UN packaging marked Z, Y, or X.
Packing Instruction P001: Instructions for liquids of Classes 3, 6.1, and 8 specifying acceptable combination, single, and IBC packagings.
Packing Instruction P002: Instructions for solid substances permitting drums, jerricans, boxes, bags, and IBCs.
Packing Instruction P620: Instructions for Category A infectious substances requiring triple packaging with primary receptacle, watertight secondary, and rigid outer.
Packing Instruction P650: Instructions for Category B infectious substances UN 3373 with triple packaging and the Category B mark.
Packing Instruction P903: Instructions for lithium ion and lithium metal batteries UN 3090, 3091, 3480, 3481.
Pesticides: Class 6.1 or 3 substances under UN 2588, 2783, 3017, and others with specific Recommendations on the Safe Use of Pesticides in the IMDG Supplement.
Petroleum Distillates NOS UN 1268: A Class 3 flammable liquid generic entry, packing group I, II, or III based on flashpoint and initial boiling point.
Placard: An enlarged hazard label of at least 250 mm x 250 mm displayed on each of the four sides of a CTU under Chapter 5.3.
Polymerising Substance: Substance liable to undergo strongly exothermic reaction resulting in formation of larger molecules, classified under UN 3531-3534.
Portable Tank: Multimodal tank designed to be filled and discharged without removal from the structural framework, IMDG Chapter 6.7.
Primary Hazard Label: The label corresponding to the primary class assignment of a dangerous good, displayed on the package.
Propane UN 1978: A Class 2.1 flammable liquefied gas.
Proper Shipping Name (PSN): The portion of the entry most accurately describing the goods in 3.1.2, written in capitals in some references and shown in column 2 of the DGL.

Q

Q Value: A summation calculation in 2.7.2.4.1.2 for Class 7 packages containing mixed radionuclides.
Quantity Limitations: Limits per package for passenger versus cargo aircraft mirrored in IMDG for limited quantity and excepted quantity thresholds.
Quantity per Package Limit (LQ): The maximum inner packaging quantity per 3.4.6 for limited quantity transport.

R

Radioactive Material Type A Package: UN 2915, 3327 fissile excepted, or 3332 special form, Class 7 by content.
Radioactive Material Type B(M) Package: UN 2917, Class 7.
Radioactive Material Type B(U) Package: UN 2916, Class 7.
Radioactive Material Type C Package: UN 3323, Class 7.
Refrigerated Liquefied Gases: Class 2.2 or 2.3 deeply refrigerated cryogens such as LNG (2.1), LIN (2.2), or LOX (2.2 + 5.1).
Reportable Quantity (RQ): A U.S. specific quantity threshold under 49 CFR 172.101 not part of IMDG but relevant for US-flag intermodal moves.
Reporting Procedures: General principles in MSC/Circ.1586 for reporting incidents involving dangerous goods at sea, in the IMDG Supplement.

S

SADT (Self-Accelerating Decomposition Temperature): The lowest temperature at which self-accelerating decomposition may occur in a substance in the packaging used in transport, used to classify Class 5.2 and 4.1 self-reactives.
Salvage Cylinder: A cylinder used to recover damaged or leaking cylinders, per 6.2.3.11.
Salvage Packaging: Special packaging into which damaged or leaking dangerous goods packages are placed for recovery, IMDG 6.1.5.1.11.
Segregation Code 1 (Away from): Minimum segregation per Table 7.2.4 keeping packages effectively segregated to avoid dangerous interaction.
Segregation Code 2 (Separated from): Vertical separation by a deck (steel) plus horizontal separation by no less than 6 m on deck.
Segregation Code 3 (Separated by a complete compartment or hold from): Either vertical or horizontal separation by an intervening complete compartment or hold; on deck a minimum of 12 m horizontal separation.
Segregation Code 4 (Separated longitudinally by an intervening complete compartment or hold from): Vertical separation alone not acceptable; on deck at least 24 m fore and aft separation including an intervening complete compartment.
Segregation Groups: Groups in 3.1.4 such as SGG1 acids, SGG2 ammonium compounds, SGG3 bromates, SGG10 liquid halogenated hydrocarbons, used as shortcut for chemical incompatibility.
Single Packaging: Packaging that does not require inner packagings to perform a containment function, such as UN approved drums and IBCs.
SOLAS Chapter VII: Carriage of dangerous goods.
Special Provision (SP): A provision in Chapter 3.3 modifying or supplementing the general DGL requirements for specific UN entries, e.g., SP 188 for small lithium batteries.
Special Provision 188: Provision for small lithium cells/batteries below 20 Wh/100 Wh thresholds, with reduced documentation but lithium battery mark required.
Special Provision 230: Provision requiring lithium cells and batteries to be type-tested under UN Manual of Tests and Criteria Part III Section 38.3.
Special Provision 274: Requirement for the technical name to be entered in parentheses after the PSN for NOS and generic entries.
Special Provision 376: Provision for damaged, defective, or recalled lithium cells and batteries, requiring UN 3090/3091/3480/3481 with special packaging conditions.
Special Provision 961: Limited quantity provision for engines and machinery exempting certain UN 3528/3529/3530 movements from full IMDG application.
Stowage Category 01-05: Under-deck stowage categories for Class 1 explosives, ranging from magazine stowage (01) to less restrictive areas (05).
Stowage Category A: On deck or under deck on cargo ships and passenger ships, the least restrictive category.
Stowage Category B: On deck or under deck on cargo ships, and on deck only on passenger ships carrying not more than 25 passengers or one passenger per 3 m of length.
Stowage Category C: On deck only on cargo ships and passenger ships meeting conditions in column 16a.