CELEX 02008R1272 · v20250901

2.8. Self-reactive substances and mixtures

2.8.1.1. Self-reactive substances or mixtures are thermally unstable liquid or solid substances or mixtures liable to undergo a strongly exothermic decomposition even without participation of oxygen (air). This definition excludes substances and mixtures classified according to this Part as explosives, organic peroxides or as oxidising.

2.8.1.2. A self-reactive substance or mixture is regarded as possessing explosive properties when in laboratory testing the formulation is liable to detonate, to deflagrate rapidly or to show a violent effect when heated under confinement.

2.8.2. Classification criteria

2.8.2.1. Any self-reactive substance or mixture shall be considered for classification in this class as a self-reactive substance or mixture unless:

(a)

they are explosives, according to the criteria given in 2.1;

(b)

they are oxidising liquids or solids, according to the criteria given in 2.13 or 2.14, except that mixtures of oxidising substances, which contain 5 % or more of combustible organic substances shall be classified as self-reactive substances according to the procedure defined in 2.8.2.2;

(c)

they are organic peroxides, according to the criteria given in 2.15;

(d)

their heat of decomposition is less than 300 J/g; or

(e)

their self-accelerating decomposition temperature (SADT) is greater than 75 oC for a 50 kg package ( 11 ).

2.8.2.2. Mixtures of oxidising substances, meeting the criteria for classification as oxidising substances, which contain 5 % or more of combustible organic substances and which do not meet the criteria mentioned in (a), (c), (d) or (e) in 2.8.2.1, shall be subjected to the self-reactive substances classification procedure;

Such a mixture showing the properties of a self-reactive substance type B to F (see 2.8.2.3) shall be classified as a self-reactive substance.

Where the test is conducted in the package form and the packaging is changed, a further test shall be conducted where it is considered that the change in packaging will affect the outcome of the test.

2.8.2.3. Self-reactive substances and mixtures shall be classified in one of the seven categories of ‘types A to G’ for this class, according to the following principles:

(a)

any self-reactive substance or mixture which can detonate or deflagrate rapidly, as packaged, shall be defined as self-reactive substance TYPE A;

(b)

any self-reactive substance or mixture possessing explosive properties and which, as packaged, neither detonates nor deflagrates rapidly, but is liable to undergo a thermal explosion in that package shall be defined as self-reactive substance TYPE B;

(c)

any self-reactive substance or mixture possessing explosive properties when the substance or mixture as packaged cannot detonate or deflagrate rapidly or undergo a thermal explosion shall be defined as self-reactive substance TYPE C;

(d)

any self-reactive substance or mixture which in laboratory testing:

(i)

detonates partially, does not deflagrate rapidly and shows no violent effect when heated under confinement; or

(ii)

does not detonate at all, deflagrates slowly and shows no violent effect when heated under confinement; or

(iii)

does not detonate or deflagrate at all and shows a medium effect when heated under confinement;

shall be defined as self-reactive substance TYPE D;

(e)

any self-reactive substance or mixture which, in laboratory testing, neither detonates nor deflagrates at all and shows low or no effect when heated under confinement shall be defined as self-reactive substance TYPE E;

(f)

any self-reactive substance or mixture which, in laboratory testing, neither detonates in the cavitated state nor deflagrates at all and shows only a low or no effect when heated under confinement as well as low or no explosive power shall be defined as self-reactive substance TYPE F;

(g)

any self-reactive substance or mixture which, in laboratory testing, neither detonates in the cavitated state nor deflagrates at all and shows no effect when heated under confinement nor any explosive power, provided that it is thermally stable (SADT is 60 oC to 75 oC for a 50 kg package), and, for liquid mixtures, a diluent having a boiling point not less than 150 oC is used for desensitisation shall be defined as self-reactive substance TYPE G. If the mixture is not thermally stable or a diluent having a boiling point less than 150 oC is used for desensitisation, the mixture shall be defined as self-reactive substance TYPE F.

2.8.2.4. Criteria for temperature control

Self-reactive substances need to be subjected to temperature control if their SADT is less than or equal to 55 oC. Test methods for determining the SADT as well as the derivation of control and emergency temperatures are given in, Part II, section 28 of the ►M4 UN RTDG ◄ , Manual of Tests and Criteria. The test selected shall be conducted in a manner which is representative, both in size and material, of the package.

2.8.3. Hazard Communication

Label elements shall be used for substances or mixtures meeting the criteria for classification in this hazard class in accordance with Table 2.8.1.

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Table 2.8.1

Label elements for self-reactive substances and mixtures

Classification	Type A	Type B	Type C & D	Type E & F	Type G (1)
GHS Pictograms					There are no label elements allocated to this hazard category
Signal Word	Danger	Danger	Danger	Warning
Hazard Statement	H240: Heating may cause an explosion	H241: Heating may cause a fire or explosion	H242: Heating may cause a fire	H242: Heating may cause a fire
Precautionary Statement Prevention	P210 P234 P235 P240 P280	P210 P234 P235 P240 P280	P210 P234 P235 P240 P280	P210 P234 P235 P240 P280
Precautionary Statement Response	P370 + P372 + P380 + P373	P370 + P380 + P375 [+ P378] (2)	P370 + P378	P370 + P378
Precautionary Statement Storage	P403 P411 P420	P403 P411 P420	P403 P411 P420	P403 P411 P420
Precautionary Statement Disposal	P501	P501	P501	P501
(1) Type G has no hazard communication elements assigned but should be considered for properties belonging to other hazard classes. (2) See the introduction to Annex IV for details on the use of square brackets.

▼B

Type G has no hazard communication elements assigned but shall be considered for properties belonging to other hazard classes.

2.8.4. Additional Classification Considerations

2.8.4.1. The properties of self-reactive substances or mixtures which are decisive for their classification shall be determined experimentally. The classification of a self reactive substance or mixture shall be performed in accordance with test series A to H as described in Part II of the ►M4 UN RTDG ◄ , Manual of Tests and Criteria. The procedure for classification is described in Figure 2.8.1.

2.8.4.2. The classification procedures for self-reactive substances and mixtures need not be applied if:

(a)

There are no chemical groups present in the molecule associated with explosive or self reactive properties. Examples of such groups are given in Tables A6.1 and A6.2 in Appendix 6 of the ►M4 UN RTDG ◄ , Manual of Tests and Criteria; or

(b)

For a single organic substance or a homogeneous mixture of organic substances, the estimated SADT for a 50 kg package is greater than 75 oC or the exothermic decomposition energy is less than 300J/g. The onset temperature and decomposition energy can be estimated using a suitable calorimetric technique (see Part II, sub-section 20.3.3.3 of the ►M4 UN RTDG ◄ , Manual of Tests and Criteria).

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Figure 2.8.1

Self-reactive substances and mixtures

Text of image

▼B

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2.8. Self-reactive substances and mixtures