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".


7.2.5 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 (stowage and segregation) 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 do not 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.

Note:
See 7.2.2.1: 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.

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 "SG5 ("segregation as for class 3)", "SG8 (stow "away from" class 4.1)", "SG13 (stow "away from class 8)", "SG25 (stow "separated from" goods of classes 2.1 and 3)" and "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 6m athwartship shall be maintained.)".

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 2014 HYDROGEN PEROXIDE, AQUEOUS SOLUTION with not less than 20% but not more than 60% hydrogen peroxide (stabilized as necessary), class 5.1, subsidiary risk 8, PG II
- UN 2984 HYDROGEN PEROXIDE, AQUEOUS SOLUTION with not less than 8% but less than 20% hydrogen peroxide (stabilized as necessary), class 5.1, PG III
- UN 3105 ORGANIC PEROXIDE TYPE D, LIQUID (peroxyacetic acid, type D, stabilized), class 5.1, subsidiary risk 8
- UN 3107 ORGANIC PEROXIDE TYPE E, LIQUID (peroxyacetic acid, type E, stabilized), class 5.1, subsidiary risk 8
- UN 3109 ORGANIC PEROXIDE TYPE F, LIQUID (peroxyacetic acid, type F, stabilized), class 5.1, subsidiary risk 8
- UN 3149 HYDROGEN PEROXIDE AND PEROXYACETIC ACID, MIXTURE with acid(s), water and not more than 5% peroxyacetic acid, STABILIZED, class 5.1, subsidiary risk 8, PG II

Table 7.2.6.3.2

- UN 1295 TRICHLOROSILANE, class 4.3, subsidiary risks 3/8, PG I
- UN 1818 SILICON TETRACHLORIDE, class 8, PG II
- UN 2189 DICHLOROSILANE, class 2.3, subsidiary risks 2.1/8

Table 7.2.6.3.3

- UN 3391 ORGANOMETALLIC SUBSTANCE, SOLID, PYROPHORIC, class 4.2, PG I
- UN 3392 ORGANOMETALLIC SUBSTANCE, LIQUID, PYROPHORIC, class 4.2, PG I
- UN 3393 ORGANOMETALLIC SUBSTANCE, SOLID, PYROPHORIC, WATER-REACTIVE, class 4.2, subsidiary risk 4.3, PG I
- UN 3394 ORGANOMETALLIC SUBSTANCE, LIQUID, PYROPHORIC, WATER-REACTIVE, class 4.2, subsidiary risk 4.3, PG I
- UN 3395 ORGANOMETALLIC SUBSTANCE, SOLID, WATER-REACTIVE, class 4.3, PG I, II, III
- UN 3396 ORGANOMETALLIC SUBSTANCE, SOLID, WATER REACTIVE, FLAMMABLE, class 4.3, subsidiary risk 4.1, PG I, II, III
- UN 3397 ORGANOMETALLIC SUBSTANCE, SOLID, WATER REACTIVE, SELF-HEATING, class 4.3, subsidiary risk 4.2, PG I, II, III
- UN 3398 ORGANOMETALLIC SUBSTANCE, LIQUID, WATER REACTIVE, class 4.3, PG I, II, III
- UN 3399 ORGANOMETALLIC SUBSTANCE, LIQUID, WATER REACTIVE, FLAMMABLE, class 4.3, subsidiary risk 3, PG I, II, III
- UN 3400 ORGANOMETALLIC SUBSTANCE, SOLID , SELF-HEATING, class 4.2, PG II, III

7.2.6.4 Notwithstanding table 7.2.6.3.4 due regard shall continue to be taken of the dangerous reactions specified in the provisions of 7.2.6.1.1 to 7.2.6.1.4.

7.2.6.5 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 litres 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.


7.3.4 Segregation provisions within cargo transport units

7.3.4.1 Dangerous goods which have to be segregated from each other according to the provisions in chapter 7.2 shall not be transported in the same cargo transport unit with the exception of dangerous goods which shall be segregated "away from" each other which may be transported in the same cargo transport unit with the approval of the competent authority. In such cases an equivalent standard of safety shall be maintained.

7.3.4.2 Segregation in relation to foodstuffs

7.3.4.2.1 Dangerous goods having a primary or subsidiary risk of classes 2.3, 6.1, 6.2, 7 (with the exception of UN 2908, 2909, 2910 and 2911), 8 and dangerous goods for which it is referred to in segregation code SG29 or SG50 in column 16b of the Dangerous Goods List shall not be transported together with foodstuffs (see 1.2.1) in the same cargo transport unit.

7.3.4.2.2 Nothwithstanding the provisions in 7.3.4.2.1, the following dangerous goods may be transported with foodstuffs provides that they are not loaded withhin 3 m from foodstuffs:

.1 dangerous goods of packing group III of classes 6.1 and 8;
.2 dangerous goods of packing group II of class 8; and
.3 any other dangerous goods of packing group III with a subsidiary hazard of classes 6.1 or 8; and
.4 dangerous goods having a reference to 7.4.3.2.2 in column 16b of the Dangerous Goods List.


7.6 Stowage and segregation on general cargo ships

7.6.3 Segregation provisions

7.6.3.1 Segregation from foodstuffs

7.6.3.1.1 For the purpose of this subsection, the terms "away from", "separated from" and "separated by a complete compartment or hold from" are defined in 7.6.3.2.

7.6.3.1.2 Dangerous goods having a primary or subsidiary risk of classes 2.3, 6.1, 7 (with the exception of UN 2908, 2909, 2910 and 2911), 8 and dangerous goods for which it is referred to in segregation code SG29 or SG50 in column 16b of the Dangerous Goods List stowed in a conventional way shall be "separated from" foodstuffs stowed in a conventional way. If either dangerous goods or foodstuffs are in a closed cargo transport unit, dangerous goods shall be stowed "away from" foodstuffs. If both dangerous goods and foodstuffs are in different closed cargo transport units, no segregation requirements shall apply.

7.6.3.1.3 Dangerous goods of class 6.2 stowed in a conventional way shall be "separated by a complete compartment or hold from" foodstuffs stowed in a conventional way. If either dangerous goods or foodstuffs are in a closed cargo transport unit, dangerous goods shall be stowed "separated from" foodstuffs.


7.7 Shipborne barges on barge-carrying ships

7.7.3 Barge loading

7.7.3.5 Dangerous goods which have to be segregated from each other according to the provisions in chapter 7.2 shall not be transported in the same barge with the exception of dangerous goods which shall be segregated "away from" each other which may be transported in the same barge with the approval of the competent authority. In such cases an equivalent standard of safety shall be maintained.

7.7.3.6 Dangerous goods having a primary or subsidiary risk of classes 2.3, 6.1, 6.2, 7 (with the exception of UN 2908, 2909, 2910 and 2911), 8 and dangerous goods for which it is referred to in segregation code SG29 or SG50 in column 16b of the Dangerous Goods List shall not be transported together with foodstuffs (see 1.2.1) in the same barge.

7.7.3.7 Notwithstanding the provisions in 7.7.3.6, the following dangerous goods may be transported with foodstuffs in the same barge provided that they are not loaded within 3 m from foodstuffs:

.1 dangerous goods of packing group III of classes 6.1 and 8;
.2 dangerous goods of packing group II of class 8;
.3 any other dangerous goods of packing group III with a subsidiary risk of classes 6.1 or 8; and
.4 dangerous goods having a reference to 7.7.3.7 in column 16b of the Dangerous Goods List.