21.7 Definitions
Clasification Society 2024 - Version 9.40
Statutory Documents - IMO Publications and Documents - International Codes - IBC Code - International Code for the Construction and Equipment of Ships Carrying Dangerous Chemicals in BulkAmended by Resolution MEPC.225(64) - Chapter 21 Criteria for assigning carriage requirements for products subject to the IBC Code - 21.7 Definitions

21.7 Definitions

 21.7.1 Acute mammalian toxicity

LC50 is the concentration in air, LD50 is the amount (dose) of test substance, which causes mortality to 50% of a test species. ATE refers to a dose (concentration) range or extrapolated dose (concentration) leading to lethal effects in mammals, equivalent to an LC50 or LD50.

21.7.1.1 Acutely toxic if swallowed

Oral toxicity (LD50/ATE) GESAMP Hazard Profile Rating C1
Hazard Level mg/kg
High ≤ 5 4
Moderately High > 5 - ≤ 50 3
Moderate > 50 - ≤ 300 2
Slight > 300 - ≤ 2000 1
Negligible > 2000 0

21.7.1.2 Acutely toxic in contact with skin

Dermal toxicity (LD50/ATE) GESAMP Hazard Profile Rating C2
Hazard Level mg/kg
High ≤ 50 4
Moderately high > 50 - ≤ 200 3
Moderate > 200 - ≤ 1000 2
Slight > 1000 - ≤ 2000 1
Negligible > 2000 0

21.7.1.3 Acutely toxic by inhalation

  • All inhalation toxicity data are assumed to be for vapours and not mists or sprays, unless otherwise indicated.

Inhalation toxicity (LC50/ATE) GESAMP Hazard Profile Rating C3
Hazard level mg/L/4h
High ≤ 0.5 4
Moderately high > 0.5 - ≤ 2 3
Moderate > 2 - ≤ 10 2
Slight > 10 - ≤ 20 1
Negligible > 20 0

21.7.2 Toxic to mammals by prolonged exposure

21.7.2.1 A product is classified as toxic to mammals by prolonged exposure if it meets any of the following criteria: it is known to be, or suspected of being carcinogenic, mutagenic, reprotoxic, neurotoxic, immunotoxic or exposure below the lethal dose is known to cause Specific Target Organ Toxicity.

21.7.2.2 Such effects may be identified from the GESAMP Hazard Profile of the product (D3 = C, M, R, T, N, or I) or other recognized sources of such information.

21.7.3 Skin sensitization

21.7.3.1 A product is classified as a skin sensitizer:

  • .1 if there is evidence in humans that the substance can induce sensitization by skin contact in a substantial number of persons; or

  • .2 where there are positive results from an appropriate test.

21.7.3.2 Such effects are identified in the GESAMP Hazard Profile for the product (D3 = Ss).

21.7.4 Respiratory sensitization

21.7.4.1 A product is classified as a respiratory sensitizer:

  • .1 if there is evidence in humans that the substance can induce specific respiratory hypersensitivity; and/or

  • .2 where there are positive results from an appropriate test; and/or

  • .3 where the product does not have a GESAMP Hazard Profile and is identified as a skin sensitizer and there is no evidence to show that it is not a respiratory sensitizer.

21.7.4.2 Such effects are identified in the GESAMP Hazard Profile for the product (D3 = Sr) or other recognized sources of such information, if no profile exists.

21.7.5 Corrosive to skinfootnote

Hazard Level Exposure time to cause full thickness necrosis of skin GESAMP Hazard Profile Rating D1
Severely corrosive to skin ≤ 3 min 3C
Highly corrosive to skin > 3 min - ≤ 1h 3B
Moderately corrosive to skin > 1h - ≤ 4h 3A

Note: A rating of 3 or (3) in the D1 column of the GESAMP Hazard Profile without any additional letter notation (A, B or C), means that the severity of corrosivity has not been established. For such cases, a rating of 3 or (3) is understood to be equivalent to a rating of 3B for the purpose of assigning carriage requirements.

21.7.6 Water reactive substances

21.7.6.1 These are classified as follows:

Water Reactive Index (WRI) Definition
3 Any chemical which is extremely reactive with water and produces large quantities of flammable, toxic or corrosive gas or aerosol
2 Any chemical which, in contact with water, may produce a toxic, flammable or corrosive gas or aerosol
1 Any chemical which, in contact with water, may generate heat or produce a non-toxic, non-flammable or non-corrosive gas
0 Any chemical which, in contact with water, would not undergo a reaction to justify a value of 1, 2 or 3

21.7.7 Air reactive substances

21.7.7.1 Air reactive substances are products that react with air to cause a potentially hazardous situation, e.g. the formation of peroxides that may cause an explosive reaction.

21.7.8 Electrical apparatus – Temperature class

  • (for products which either have a flashpoint of ≤ 60oC or are heated to within 15°C of their flashpoint)
21.7.8.1 The temperature class is defined by the International Electrotechnical Commission (IEC) as:

  • "The highest temperature attained under practical conditions of operation within the rating of the apparatus (and recognized overloads, if any, associated therewith) by any part of any surface, the exposure of which to an explosive atmosphere may involve a risk."

21.7.8.2 The temperature class of the electrical apparatus is assigned by selecting the Maximum Surface Temperature which is closest to, but less than, the product's auto-ignition temperature (see 21.4.9.1.1).

21.7.9 Electrical apparatus – Apparatus group

  • (for products with a flashpoint of ≤ 60oC)
21.7.9.1 This refers to intrinsically safe and associated electrical apparatus for explosive gas atmospheres which the IEC divide into the following groups:

  • Group I: for mines susceptible to firedamp (not used by IMO); and

  • Group II: for applications in other industries – further subdivided according to its Maximum Experimental Safe Gap (MESG) and/or the Minimum Igniting Current (MIC) of the gas/vapour into groups IIA, IIB and IIC.

21.7.9.2 This property cannot be determined from other data associated with the product; it has to be either measured or assigned by assimilation with related products in a homologous series.

21.7.10 Special carriage control conditions

21.7.10.1 Special carriage control conditions refer to specific measures that need to be taken in order to prevent a hazardous reaction. They include:

  • .1 Inhibition: the addition of a compound (usually organic) that retards or stops an undesired chemical reaction such as corrosion, oxidation or polymerization;

  • .2 Stabilization: the addition of a substance (stabilizer) that tends to keep a compound, mixture or solution from changing its form or chemical nature. Such stabilizers may retard a reaction rate, preserve a chemical equilibrium, act as antioxidants, keep pigments and other components in emulsion form or prevent the particles in colloidal suspension from precipitating;

  • .3 Inertion: the addition of a gas (usually nitrogen) in the ullage space of a tank that prevents the formation of a flammable cargo/air mixture;

  • .4 Temperature control: the maintenance of a specific temperature range for the cargo in order to prevent a hazardous reaction or to keep the viscosity low enough to allow the product to be pumped; and

  • .5 Padding and venting: only applies to specific products identified on a case by case basis.

21.7.11 Flammable cargoes

21.7.11.1 A cargo is defined as flammable according to the following criteria:

IBC Code descriptor Flashpoint (degrees Centigrade)
Highly flammable < 23
Flammable ≤ 60 but ≥ 23

21.7.11.2 It should be noted that flashpoints of mixtures and aqueous solutions need to be measured unless all of the components are non-flammable.

21.7.11.3 It should be noted that the carriage of bulk liquid cargoes that have a flashpoint of ≤ 60°C are subject to other SOLAS regulations.

21.7.12 Application of the SVC/LC50 ratio method

21.7.12.1 If the vapour pressure and the molecular weight of a substance are known, an estimate of the maximum vapour concentration in a closed compartment (e.g. a tank) can be calculated. This is called the Saturated Vapour Concentration (SVC).

21.7.12.2 The hazard quotient SVC/LC50footnote is a substance specific value for the velocity of a vapour for achieving a hazardous concentration when emerging from a liquid source (e.g. leak, spillage or tank ventilation), and can be used in the assignment of specific carriage requirements related to inhalation toxicity.

21.7.12.3 If a solid substance is transported in an aqueous solution, the vapour pressurefootnote of this solid rather than that of water may be used in the calculation of the SVC/LC50 ratio.

21.7.12.4 Application of the SVC/LC50 ratio for assigning Ship Type and Tank type

21.7.12.4.1 For the assignment of Ship Type and tank type, as set out in paragraph 21.4.5 and 21.4.6, the application of the SVC/LC50 ratio method is optional. Should this method be used, the vapour pressure at 20°C shall be used when calculating the SVC/LC50 ratio.

21.7.12.4.2 The SVC mg/L of a substance should be calculated as follows:

  • where MW is the molecular weight of the substance.

21.7.12.4.3 The SVC/LC50 ratio should be calculated as follows:

21.7.12.5 Application of the SVC/LC50 ratio for assigning carriage requirements

21.7.12.5.1 For the carriage requirements listed in 21.7.12.5.5, the application of the SVC/LC50 ratio method is optional. If the SVC/LC50 ratio method is used in the assignment of these carriage requirements, the vapour pressure at 40°C shall be used when calculating the SVC/LC50 ratio. If the carriage temperature is higher than 40°C, then the SVC/LC50 ratio should be calculated at that temperature.

21.7.12.5.2 The SVC (mg/l) of a substance should be calculated as follows:

where MW is the molecular weight of the substance.

21.7.12.5.3 The SVC/LC50 ratio should be calculated as follows:

21.7.12.5.4 The SVC (mg/L) formula described in 21.7.12.5.2 is standardized for calculations at 40°C. When using the vapour pressure at higher temperatures in the calculations, the formula must be amended accordingly.

21.7.12.5.5 For the following carriage requirements, the SVC/LC50 ratio method, calculated at 40°C or higher, may be used as an alternative to the acute inhalation toxicity criteria given in paragraphs 21.4 and 21.5:

.1 Column g – Tank vents
  Assignment of controlled venting is not required based on the inhalation hazard only, if:
  Inhalation LC50/ATE ≤ 10 mg/L/4h (C3 = 2, 3, or 4) and SVC/LC50 < 0.2
.2 Column j – Gauging
  Closed gauging is not required based on the inhalation hazard only, if:
  Inhalation LC50/ATE ≤ 2 mg/L/4h (C3 = 3 or 4) and SVC/LC50 < 0.2 but restricted gauging is required.
  Restricted gauging is not required based on the inhalation hazard only, if:
  Inhalation LC50/ATE > 2 - ≤ 10 mg/L/4h (C3 = 2) and SVC/LC50 < 0.2
.3 Column k – Vapour detection
  Assignment of toxic vapour detection is not required based on the inhalation hazard only, if:
  Inhalation LC50/ATE ≤ 10 mg/L/4h (C3 = 2, 3, or 4) and SVC/LC50 < 0.2
.4 Column n – Emergency Equipment
  Inhalation LC50/ATE ≤ 2 mg/L/4h (C3 = 3 or 4) and SVC/LC50 < 0.2
.5 Column o – Special requirements in chapter 15
  15.12.1 and 15.12.2 are not required based on the inhalation hazard only, if:
  Inhalation LC50/ATE ≤ 2 mg/L/4h (C3 = 3 or 4) and SVC/LC50 < 0.2
  15.12.3 and 15.12.4 are not required based on the inhalation hazard only, if:
  Inhalation LC50/ATE >2 - ≤ 10 mg/L/4h (C3 = 2) and SVC/LC50 < 0.2
  15.17 is not required based on the inhalation hazard only, if:
  Inhalation LC50/ATE ≤ 0.5 mg/L/4h (C3 = 4) and SVC/LC50 < 0.2
  15.18 is not required based on the inhalation hazard only if:
  Inhalation LC50/ATE ≤ 0.5 mg/L/4h (C3 = 4) and SVC/LC50 < 0.2
  15.19 is not required based on the inhalation hazard only, if:
  Inhalation LC50/ATE ≤ 2 mg/L/4h (C3 = 3 or 4) and SVC/LC50 < 0.2, but 15.19.6 applies
  15.19.6 is not required based on the inhalation hazard only, if:
  Inhalation LC50/ATE > 2 - ≤ 10 mg/L/4h (C3 = 2) and SVC/LC50 < 0.2
Parent topic: Chapter 21 Criteria for assigning carriage requirements for products subject to the IBC Code
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