Chapter 7.2


General segregation provisions

7.2.1

Introduction

This chapter contains the general provisions for the segregation of goods which are mutually incompatible.

Additional segregation provisions are given in:

  • 7.3 Consigning operations concerning the packing and use of cargo transport units (CTUs) and related provisions;

  • 7.4 Stowage and segregation on containerships;

  • 7.5 Stowage and segregation on roll-on/roll-off ships;

  • 7.6 Stowage and segregation on general cargo ships; and

  • 7.7 Shipborne barges on barge-carrying ships.

7.2.2
Definitions
7.2.2.1

Segregation

Segregation is the process of separating two or more substances or articles which are considered mutually incompatible when their packing or stowage together may result in undue hazards in case of leakage or spillage, or any other accident.

However, as the extent of the hazard arising may vary, the segregation arrangements required may also vary as appropriate. Segregation is obtained by maintaining certain distances between incompatible dangerous goods or by requiring the presence of one or more steel bulkheads or decks between them, or a combination thereof. Intervening spaces between such dangerous goods may be filled with other cargo compatible with the dangerous substances or articles in question.

7.2.2.2

Segregation terms

The following segregation terms that are used throughout this Code are defined in other chapters of this part as they apply to packing cargo transport units and segregation on board different ship types:

  1. "away from";

  2. "separated from";

  3. "separated by a complete compartment or hold from";

  4. "separated longitudinally by an intervening complete compartment or hold from".

Segregation terms such as "away from class ..." that are used in the Dangerous Goods List, "class ..." is deemed to include:

  1. all substances within "class ..."; and

  2. all substances for which a subsidiary risk label of "class ..." is required.

7.2.3
Segregation provisions
7.2.3.1
To determine the segregation requirements between two or more dangerous goods, the segregation provisions, including the segregation table (7.2.4) and column 16b of the Dangerous Goods List shall be consulted, see also the annex to this chapter. In case of conflicting provisions, the provisions of column 16b of the Dangerous Goods List, always take precedence.
7.2.3.2

Whenever a segregation term applies (see 7.2.2.2), the goods are:

  1. not permitted to be packed in the same outer packaging; and

  2. not permitted to be transported in the same cargo transport unit except as provided in 7.2.6 and 7.3.4.

For "limited quantities" and "excepted quantities" see chapters 3.4 and 3.5.

7.2.3.3
Where the provisions of this Code indicate a single secondary hazard (one subsidiary risk label), the segregation provisions applicable to that hazard shall take precedence where they are more stringent than those of the primary hazard. The segregation provisions corresponding to a subsidiary risk of class 1 are those for class 1 division 1.3.
7.2.3.4

The segregation provisions for substances, materials or articles having more than two hazards (two or more subsidiary risk labels) are given in column 16b of the Dangerous Goods List.

For example:

  • In the Dangerous Goods List entry for BROMINE CHLORIDE, class 2.3, UN 2901, subsidiary risks 5.1 and 8, the following particular segregation is specified:

    "segregation as for class 5.1, but "separated from" class 7".

7.2.4

Segregation table

The general provisions for segregation between the various classes of dangerous goods are shown in the "segregation table" given below.

Since the properties of substances, materials or articles within each class may vary greatly, the Dangerous Goods List shall always be consulted for particular provisions for segregation as, in the case of conflicting provisions, these take precedence over the general provisions.

Segregation shall also take account of a single subsidiary risk label.

CLASS 1.1 1.2 1.5 1.3 1.6 1.4 2.1 2.2 2.3 3 4.1 4.2 4.3 5.1 5.2 6.1 6.2 7 8 9
Explosives 1.1, 1.2, 1.5 * * * 4 2 2 4 4 4 4 4 4 2 4 2 4 X
Explosives 1.3, 1.6 * * * 4 2 2 4 3 3 4 4 4 2 4 2 2 X
Explosives 1.4 * * * 2 1 1 2 2 2 2 2 2 X 4 2 2 X
Flammable gases 2.1 4 4 2 X X X 2 1 2 2 2 2 X 4 2 1 X
Non-toxic, non-flammable gases 2.2 2 2 1 X X X 1 X 1 X X 1 X 2 1 X X
Toxic gases 2.3 2 2 1 X X X 2 X 2 X X 2 X 2 1 X X
Flammable liquids 3 4 4 2 2 1 2 X X 2 2 2 2 X 3 2 X X
Flammable solids (including self-reactive substances and solid desensitized explosives) 4.1 4 3 2 1 X X X X 1 X 1 2 X 3 2 1 X
Substances liable to spontaneous combustion 4.2 4 3 2 2 1 2 2 1 X 1 2 2 1 3 2 1 X
Substances which, in contact with water, emit flammable gases 4.3 4 4 2 2 X X 2 X 1 X 2 2 X 2 2 1 X
Oxidizing substances (agents) 5.1 4 4 2 2 X X 2 1 2 2 X 2 1 3 1 2 X
Organic peroxides 5.2 4 4 2 2 1 2 2 2 2 2 2 X 1 3 2 2 X
Toxic substances 6.1 2 2 X X X X X X 1 X 1 1 X 1 X X X
Infectious substances 6.2 4 4 4 4 2 2 3 3 3 2 3 3 1 X 3 3 X
Radioactive material 7 2 2 2 2 1 1 2 2 2 2 1 2 X 3 X 2 X
Corrosive substances 8 4 2 2 1 X X X 1 1 1 2 2 X 3 2 X X
Miscellaneous dangerous substances and articles 9 X X X X X X X X X X X X X X X X X

The numbers and symbols in the table have the following meanings:

1 - "away from"

2 - "separated from"

3 - "separated by a complete compartment or hold from"

4 - "separated longitudinally by an intervening complete compartment or hold from"

X - the Dangerous Goods List has to be consulted to verify whether there are specific segregation provisions

* - see 7.2.7.1 of this chapter for the segregation provisions between class 1 substances or articles

7.2.5
Segregation groups
7.2.5.1
For the purpose of segregation, dangerous goods having certain similar chemical properties have been grouped together in segregation groups as listed in 7.2.5.2. The entries allocated to these segregation groups are listed in 3.1.4.4. Where in the Dangerous Goods List entry in column 16b a particular segregation requirement refers to a group of substances, such as "acids", the particular segregation requirement applies to the goods allocated to the respective segregation group.
7.2.5.2

Segregation groups referred to in the Dangerous Goods List:

  1. acids
  2. ammonium compounds
  3. bromates
  4. chlorates
  5. chlorites
  6. cyanides
  7. heavy metals and their salts (including their organometallic compounds)
  8. hypochlorites
  9. lead and its compounds
  10. liquid halogenated hydrocarbons
  11. mercury and mercury compounds
  12. nitrites and their mixtures
  13. perchlorates
  14. permanganates
  15. powdered metals
  16. peroxides
  17. azides
  18. alkalis.
7.2.5.3
It is recognized that not all substances, mixtures, solutions or preparations falling within a segregation group are listed in the IMDG Code by name. These are shipped under N.O.S. entries. Although these N.O.S. entries are not themselves listed in the segregation groups (see 3.1.4.4), the consignor shall decide whether inclusion under the segregation group is appropriate and, if so, shall mention that fact in the transport document (see 5.4.1.5.11).
7.2.5.4
The segregation groups in this Code do not cover substances which fall outside the classification criteria of this Code. It is recognized that some non-hazardous substances have similar chemical properties as substances listed in the segregation groups. A consignor or the person responsible for packing the goods into a cargo transport unit who does have knowledge of the chemical properties of such non-dangerous goods may decide to implement the segregation requirements of a related segregation group on a voluntary basis.
7.2.6
Special segregation provisions and exemptions
7.2.6.1

Notwithstanding 7.2.3.3 and 7.2.3.4, substances of the same class may be stowed together without regard to segregation required by secondary hazards (subsidiary risk label(s)), provided that the substances do not react dangerously with each other and cause:

  1. combustion and/or evolution of considerable heat;

  2. evolution of flammable, toxic or asphyxiant gases;

  3. the formation of corrosive substances; or

  4. the formation of unstable substances.

7.2.6.2

Where the Dangerous Goods List specifies that "segregation as for class ..." applies, the segregation provisions applicable to that class in 7.2.4 shall be applied. However, for the purposes of interpreting 7.2.6.1, which permits substances of the same class to be stowed together provided they do not react dangerously with each other, the segregation provisions of the class as represented by the primary hazard class in the Dangerous Goods List shall be applied.

For example:

  • UN 2965 - BORON TRIFLUORIDE DIMETHYL ETHERATE, class 4.3
  • The Dangerous Goods List entry specifies "segregation as for class 3, but "away from" classes 4.1 and 8".
  • For the purposes of establishing the segregation provisions applicable in 7.2.4, the class 3 column shall be consulted.
  • This substance may be stowed together with other class 4.3 substances where they do not react dangerously with each other, see 7.2.6.1.
7.2.6.3

No segregation needs to be applied:

  1. between dangerous goods of different classes which comprise the same substance but vary only in their water content, such as sodium sulphide in classes 4.2 and 8 or for class 7 if the difference is due to quantity only; and

  2. between dangerous goods which belong to a group of substances of different classes but for which scientific evidence exists that they do not react dangerously when in contact with each other. Substances within the same table shown below are compatible with one another.

Table 7.2.6.3.1
UN Proper shipping name Class Subsidiary risk(s) Packing group
2014 HYDROGEN PEROXIDE, AQUEOUS SOLUTION with not less than 20% but not more than 60% hydrogen peroxide (stabilized as necessary) 5.1 8 II
2984 HYDROGEN PEROXIDE, AQUEOUS SOLUTION with not less than 8% but less than 20% hydrogen peroxide (stabilized as necessary) 5.1 8 III
3105 ORGANIC PEROXIDE TYPE D, LIQUID (peroxyacetic acid, type D, stabilized) 5.2 8
3107 ORGANIC PEROXIDE TYPE E, LIQUID (peroxyacetic acid, type E, stabilized) 5.2 8
3109 ORGANIC PEROXIDE TYPE F, LIQUID (peroxyacetic acid, type F, stabilized) 5.2 8
3149 HYDROGEN PEROXIDE AND PEROXYACETIC ACID, MIXTURE with acid(s), water and not more than 5% peroxyacetic acid, STABILIZED 5.2 8 II
Table 7.2.6.3.2
UN Proper shipping name Class Subsidiary risk(s) Packing group
1295 TRICHLOROSILANE 4.3 3/8 I
1818 SILICON TETRACHLORIDE 8 - II
2189 DICHLOROSILANE 2.3 2.1/8 -
Table 7.2.6.3.3
UN Proper shipping name Class Subsidiary risk(s) Packing group
3391 ORGANOMETALLIC SUBSTANCE, SOLID, PYROPHORIC 4.2 I
3392 ORGANOMETALLIC SUBSTANCE, LIQUID, PYROPHORIC 4.2 I
3393 ORGANOMETALLIC SUBSTANCE, SOLID, PYROPHORIC, WATER-REACTIVE 4.2 4.3 I
3394 ORGANOMETALLIC SUBSTANCE, LIQUID, PYROPHORIC, WATER-REACTIVE 4.2 4.3 I
3395 ORGANOMETALLIC SUBSTANCE, SOLID, WATER-REACTIVE 4.3 I, II, III
3396 ORGANOMETALLIC SUBSTANCE, SOLID, WATER REACTIVE, FLAMMABLE 4.3 4.1 I, II, III
3397 ORGANOMETALLIC SUBSTANCE, SOLID, WATER REACTIVE, SELF-HEATING 4.3 4.2 I, II, III
3398 ORGANOMETALLIC SUBSTANCE, LIQUID, WATER REACTIVE 4.3 I, II, III
3399 ORGANOMETALLIC SUBSTANCE, LIQUID, WATER REACTIVE, FLAMMABLE 4.3 3 I, II, III
3400 ORGANOMETALLIC SUBSTANCE, SOLID , SELF-HEATING 4.2 II, III
7.2.6.4

Notwithstanding the provisions of 7.2.5, substances of class 8, packing group II or III, that would otherwise be required to be segregated from one another due to the provisions pertaining to segregation groups as identified by an entry in column 16b of the Dangerous Goods List indicating "away from" or "separated from" "acids" or "away from" or "separated from" "alkalis", may be transported in the same cargo transport unit, whether in the same packaging or not, provided:

  1. the substances comply with the provisions of 7.2.6.1;

  2. the package does not contain more than 30 L for liquids or 30 kg for solids;

  3. the transport document includes the statement required by 5.4.1.5.11.3; and

  4. a copy of the test report that verifies that the substances do not react dangerously with each other shall be provided if requested by the competent authority.

7.2.7
Segregation of goods of class 1
7.2.7.1
Segregation between goods of class 1
7.2.7.1.1
Goods of class 1 may be stowed within the same compartment or hold, or closed cargo transport unit as indicated in 7.2.7.1.4. In other cases, they shall be stowed in separate compartments or holds, or closed cargo transport units.
7.2.7.1.2
When goods requiring different stowage arrangements are permitted by 7.2.7.1.4 to be transported in the same compartment or hold, or closed cargo transport unit, the appropriate stowage arrangement shall conform to the most stringent provisions for the entire load.
7.2.7.1.3
Where a mixed load of different divisions is transported within the same compartment or hold, or closed cargo transport unit, the entire load shall be treated as if belonging to the hazard division in the order 1.1 (most dangerous), 1.5, 1.2, 1.3, 1.6 and 1.4 (least dangerous) and the stowage arrangement shall conform to the most stringent provisions for the entire load.
7.2.7.1.4

Permitted mixed stowage for goods of class 1

Compatibility group A B C D E F G H J K L N S
A X
B X X
C X X6 X6 X1 X4 X
D X6 X X6 X1 X4 X
E X6 X6 X X1 X4 X
F X X
G X1 X1 X1 X X
H X X
J X X
K X X
L X2
N X4 X4 X4 X3 X5
S X X X X X X X X X X5 X

"X" indicates that goods of the corresponding compatibility groups may be stowed in the same compartment, hold, or closed cargo transport unit.

Notes
1 Explosive articles in compatibility group G (other than fireworks and those requiring special stowage) may be stowed with explosive articles of compatibility groups C, D and E provided no explosive substances are transported in the same compartment or hold, or closed cargo transport unit.
2 A consignment of one type in compatibility group L shall only be stowed with a consignment of the same type within compatibility group L.
3 Different types of articles of Division 1.6, compatibility group N, may only be transported together when it is proven that there is no additional risk of sympathetic detonation between the articles. Otherwise they shall be treated as division 1.1.
4 When articles of compatibility group N are transported with articles or substances of compatibility groups C, D or E, the goods of compatibility group N shall be treated as compatibility group D.
5 When articles of compatibility group N are transported together with articles or substances of compatibility group S, the entire load shall be treated as compatibility group N.
6 Any combination of articles in compatibility groups C, D and E shall be treated as compatibility group E. Any combination of substances in compatibility groups C and D shall be treated as the most appropriate compatibility group shown in 2.1.2.3, taking into account the predominant characteristics of the combined load. This overall classification code shall be displayed on any label or placard placed on a unit load or closed cargo transport unit as prescribed in 5.2.2.2.2.

7.2.7.1.5
Closed cargo transport units carrying different goods of class 1 do not require segregation from each other provided 7.2.7.1.4 authorizes the goods to be transported together. Where this is not permitted, closed cargo transport unit shall be "separated from" one another.
7.2.7.2
Segregation from goods of other classes
7.2.7.2.1

Notwithstanding the segregation provisions of this chapter, AMMONIUM NITRATE (UN 1942), AMMONIUM NITRATE FERTILIZERS (UN 2067), alkali metal nitrates (e.g. UN 1486) and alkaline earth metal nitrates (e.g. UN 1454) may be stowed together with blasting explosives (except EXPLOSIVE, BLASTING, TYPE C, UN 0083) provided the aggregate is treated as blasting explosives under class 1.

Note: Alkali metal nitrates include caesium nitrate (UN 1451), lithium nitrate (UN 2722), potassium nitrate (UN 1486), rubidium nitrate (UN 1477) and sodium nitrate (UN 1498). Alkaline earth metal nitrates include barium nitrate (UN 1446), beryllium nitrate (UN 2464), calcium nitrate (UN 1454), magnesium nitrate (UN 1474) and strontium nitrate (UN 1507).

7.2.8

Segregation codes

The segregation codes given in column 16b of the Dangerous Goods List are as specified below:

Segregation Code Description
SG1 For packages carrying a subsidiary risk label of class 1, segregation as for class 1, division 1.3.
SG2 Segregation as for class 1.2G.
SG3 Segregation as for class 1.3G.
SG4 Segregation as for class 2.1.
SG5 Segregation as for class 3.
SG6 Segregation as for class 5.1.
SG7 Stow "away from" class 3.
SG8 Stow "away from" class 4.1.
SG9 Stow "away from" class 4.3.
SG10 Stow "away from" class 5.1.
SG11 Stow "away from" class 6.2.
SG12 Stow "away from" class 7.
SG13 Stow "away from" class 8.
SG14 Stow "separated from" class 1 except for division 1.4S.
SG15 Stow "separated from" class 3.
SG16 Stow "separated from" class 4.1.
SG17 Stow "separated from" class 5.1.
SG18 Stow "separated from" class 6.2.
SG19 Stow "separated from" class 7.
SG20 Stow "away from" acids.
SG21 Stow "away from" alkalis.
SG22 Stow "away from" ammonium salts.
SG23 Stow "away from" animal or vegetable oils.
SG24 Stow "away from" azides.
SG25 Stow "separated from" goods of classes 2.1 and 3.
SG26 In addition: from goods of classes 2.1 and 3 when stowed on deck of a containership a minimum distance of two container spaces athwartship shall be maintained, when stowed on ro-ro ships a distance of 6 m athwartship shall be maintained.
SG27 Stow "away from" explosives containing chlorates or perchlorates.
SG28 Stow "away from" ammonium compounds and explosives containing ammonium compounds or salts.
SG29 Segregation from foodstuffs as in 7.3.4.2.2, 7.6.3.1.2 or 7.7.3.7.
SG30 Stow "away from" heavy metals and their salts.
SG31 Stow "away from" lead and its compounds.
SG32 Stow "away from" liquid halogenated hydrocarbons.
SG33 Stow "away from" powdered metals.
SG34 When containing ammonium compounds, "away from" chlorates or perchlorates and explosives containing chlorates or perchlorates.
SG35 Stow "separated from" acids.
SG36 Stow "separated from" alkalis.
SG37 Stow "separated from" ammonia.
SG38 Stow "separated from" ammonium compounds.
SG39 Stow "separated from" ammonium compounds other than AMMONIUM PERSULPHATE (UN 1444).
SG40 Stow "separated from" ammonium compounds other than mixtures of ammonium persulphates and/or potassium persulphates and/or sodium persulphates.
SG41 Stow "separated from" animal or vegetable oil.
SG42 Stow "separated from" bromates.
SG43 Stow "separated from" bromine.
SG44 Stow "separated from" CARBON TETRACHLORIDE (UN 1846).
SG45 Stow "separated from" chlorates.
SG46 Stow "separated from" chlorine.
SG47 Stow "separated from" chlorites.
SG48 Stow "separated from" combustible material (particularly liquids). Combustible material does not include packing materials or dunnage.
SG49 Stow "separated from" cyanides.
SG50 Segregation from foodstuffs as in 7.3.4.2.1, 7.6.3.1.2 or 7.7.3.6.
SG51 Stow "separated from" hypochlorites.
SG52 Stow "separated from" iron oxide.
SG53 Stow "separated from" liquid organic substances.
SG54 Stow "separated from" mercury and mercury compounds.
SG55 Stow "separated from" mercury salts.
SG56 Stow "separated from" nitrites.
SG57 Stow "separated from" odour-absorbing cargoes.
SG58 Stow "separated from" perchlorates.
SG59 Stow "separated from" permanganates.
SG60 Stow "separated from" peroxides.
SG61 Stow "separated from" powdered metals.
SG62 Stow "separated from" sulphur.
SG63 Stow "separated longitudinally by an intervening complete compartment or hold from" class 1.
SG64 [Reserved]
SG65 Stow "separated by a complete compartment or hold from" class 1 except for division 1.4.
SG66 [Reserved]
SG67 Stow "separated from" division 1.4 and "separated longitudinally by an intervening complete compartment of hold from" divisions 1.1, 1.2, 1.3, 1.5 and 1.6 except from explosives of compatibility group J.
SG68 If flashpoint 60ºC c.c. or below, segregation as for class 3 but "away from" class 4.1.
SG69 For AEROSOLS with a maximum capacity of 1 L: segregation as for class 9. Stow "separated from" class 1 except for division 1.4.
For AEROSOLS with a capacity above 1 L: segregation as for the appropriate subdivision of class 2.
For WASTE AEROSOLS: segregation as for the appropriate subdivision of class 2.
SG70 For arsenic sulphides, "separated from" acids.
SG71 Within the appliance, to the extent that the dangerous goods are integral parts of the complete life-saving appliance, there is no need to apply the provisions on segregation of substances in chapter 7.2.
SG72 See 7.2.6.3.2.
SG73 [Reserved]
SG74 Segregation as for 1.4G.
SG75 Stow "separated from" strong acids.
Annex
Segregation flow chart

Segregation flow chart

Examples

 

The following examples only illustrate the process of segregation. Subsequent additional provisions of this Code may apply (e.g., 7.3.4).

  1. Segregation of 300 kg of celluloid, scrap (UN 2002) in one drum and 200 L of epibromohydrin (UN 2558) in one drum.

    1. According to the Dangerous Goods List, UN 2002 is class 4.2, PG III, and UN 2558 is class 6.1, PG I and has a subsidiary risk of class 3.

    2. Neither are exempted by 3.4, 3.5, 7.2.6.3 or 7.2.6.4.

    3. There are no specific segregation requirements for these substances in column 16b of the Dangerous Goods List.

    4. According to the segregation table given in 7.2.4 for classes 4.2 and 6.1, the intersecting box shows number 1, whereas for classes 4.2 and 3, the intersecting box shows a number 2. The value 2 is the more stringent, therefore the substances are required to be "separated from" one another.

  2. Segregation of 50 kg of potassium perchlorate (UN 1489) in one drum and 50 kg of nickel cyanide (UN 1653) in one drum.

    1. According to the Dangerous Goods List, UN 1489 is class 5.1, PG II and UN 1653 is class 6.1, PG II.

    2. Neither are exempted by 3.4, 3.5, 7.2.6.3 or 7.2.6.4.

    3. For UN 1489, column 16b of the Dangerous Goods List states: ""separated from" ammonium compounds and cyanides".

    4. For UN 1653, column 16b of the Dangerous Goods List states: ""separated from" acids".

    5. According to the segregation table given in 7.2.4 for classes 5.1 and 6.1, the intersecting box shows a number "1".

    6. According to the segregation groups in section 3.1.4, UN 1653 is listed in group 6 (cyanides).

    7. Therefore, the substances are required to be "separated from" one another.

  3. Segregation of 10 kg of acetone (UN 1090) in one box and 20 kg of ethyldichlorosilane (UN 1183) in another box.

    1. According to the Dangerous Goods List, UN 1090 is class 3, PG II.

    2. According to the Dangerous Goods List, UN 1183 is class 4.3, PG I and has subsidiary risks of classes 3 and 8.

    3. Neither are exempted by 3.4, 3.5, 7.2.6.3 or 7.2.6.4.

    4. UN 1090 has no specific segregation requirements in column 16b.

    5. For UN 1183, column 16b of the Dangerous Goods List states: "Segregation as for class 3 but "away from" classes 3, 4.1 and 8".

    6. According to the segregation table given in 7.2.4, the intersecting box shows an "X" for classes 3 and 3, but as UN 1183 is required to be "away from" class 3, the substances are required to be "away from" one another.

  4. Segregation of 10 kg of adhesives (UN 1133, PG III) in limited quantities and 40 kg of beryllium nitrate (UN 2464) in the same freight container.

    1. According to the Dangerous Goods List, UN 1133 is class 3, PG III.

    2. According to the Dangerous Goods List, UN 2464 is class 5.1, PG II and has a subsidiary risk of class 6.1.

    3. According to section 3.4, UN 1133 in limited quantities is exempted from the segregation provisions of Part 7.

    4. Therefore, no segregation requirements shall apply.

Chapter 7.1

Chapter 7.3