Dangerous Goods by Road
self-reactive substances definitions
for the purposes of adr, self-reactive substances are thermally unstable substances liable to undergo
a strongly exothermic decomposition even without participation of oxygen (air). substances are not
considered to be self-reactive substances of class 4.1, if:
(a) they are explosives according to the criteria of class 1;
(b) they are oxidizing substances according to the classification procedure for class 5.1
(see 2.2.51.1) except that mixtures of oxidizing substances which contain 5% or more of
combustible organic substances shall be subjected to the classification procedure defined in
note 2;
(c) they are organic peroxides according to the criteria of class 5.2 (see 2.2.52.1);
(d) their heat of decomposition is less than 300 j/g; or
(e) their self-accelerating decomposition temperature (sadt) (see note 3 below) is greater than
75 °c for a 50 kg package.
note 1: the heat of decomposition can be determined using any internationally recognised method
e.g. differential scanning calorimetry and adiabatic calorimetry.
note 2: mixtures of oxidizing substances meeting the criteria of class 5.1 which contain 5% or
more of combustible organic substances, which do not meet the criteria mentioned in (a), (c), (d) or
(e) above, shall be subjected to the self-reactive substance classification procedure.
a mixture showing the properties of a self-reactive substance, type b to f, shall be classified as a selfreactive
substance of class 4.1.
a mixture showing the properties of a self-reactive substance, type g, according to the principle given
in section 20.4.3 (g) of part ii of the manual of tests and criteria shall be considered for
classification as a substance of class 5.1 (see 2.2.51.1).
note 3: the self-accelerating decomposition temperature (sadt) is the lowest temperature at which
self-accelerating decomposition may occur with a substance in the packaging as used during
carriage. requirements for the determination of the sadt are given in the manual of tests and
criteria, part ii, chapter 20 and section 28.4.
note 4: any substance which shows the properties of a self-reactive substance shall be classified as
such, even if this substance gives a positive test result according to 2.2.42.1.5 for inclusion in
class 4.2.