# Regulation (EC) No 1272/2008 of the European Parliament and of the Council of 16 December 2008 on classification, labelling and packaging of substances and mixtures, amending and repealing Directives 67/548/EEC and 1999/45/EC, and amending Regulation (EC) No 1907/2006 (Text with EEA relevance), Division 2.12.2.1: A substance or mixture which, in contact with water, emits flammable gases shall be classified in one of the three categories for this class, using test N.5 in Part III, sub-section 33.4.1.4 of the UN RTDG, Manual of Tests and Criteria, in accordance with Table 2.12.1:

Extent: E+W+S+N.I.

Table 2.12.1
Criteria for substances and mixtures, which in contact with water, emit flammable gases
Category
Criteria
1
Any substance or mixture which reacts vigorously with water at ambient temperatures and demonstrates generally a tendency for the gas produced to ignite spontaneously, or which reacts readily with water at ambient temperatures such that the rate of evolution of flammable gas is equal to or greater than 10 litres per kilogram of substance over any one minute.
2
Any substance or mixture which reacts readily with water at ambient temperatures such that the maximum rate of evolution of flammable gas is equal to or greater than 20 litres per kilogram of substance per hour, and which does not meet the criteria for Category 1.
3
Any substance or mixture which reacts slowly with water at ambient temperatures such that the maximum rate of evolution of flammable gas is greater than 1 litre per kilogram of substance per hour, and which does not meet the criteria for Categories 1 and 2.

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Source: https://www.legislation.gov.uk/eur/2008/1272/annex/I/division/2/division/2.12/division/2.12.2/division/2.12.2.1 (the official version)
Page: https://openlegislation.uk/eu-regulation-2008-1272/annex-I/division-2/division-2.12/division-2.12.2/division-2.12.2.1
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.