Last edit: 03/08/2023
The Atex Classification of places with danger of explosion (atex zone) due to the presence of explosives, flammable fluids and combustible dusts was in the past the subject of the Atex Standard CEI 64-2 and the relative appendix CEI 64-2/A.
This standard was of national origin, and was neither harmonised nor unified at European level, since until 1996 there were no harmonisation documents (HD) or CENELEC standards (EN) on the subject.
In September 2002, CENELEC published standard EN 50281-3 "Electrical apparatus for explosive atmospheres in the presence of combustible dust – Part 3: Classification of hazardous places where combustible dust is present or may be present", which CEI transposed as national standard CEI EN 50281-3 (CEI 31-52), first edition, issue 6947, dated June 2003.
Standard CEI EN 50281-3 (CEI 31-52) introduced a new philosophy (new terms and new concepts) that made the terminology and methods of place classification used in Standard CEI 64-2 obsolete. In particular, the definition of a Class 2 location (for flammable dusts) and the term Danger Centre in standard CEI 64-2 do not appear there and zones 20, 21 and 22, not present in standard CEI 64-2, have been introduced, in analogy with zones 0, 1 and 2 for flammable gases, vapours and mists.
In order to comply with the timescales of Directive 1999/92/EC and Legislative Decree 233/03, on 30 June 2003, Chapter IV CLASS 2 (C2) PLACES of standard CEI 64-2 fourth edition was repealed.
In October 2005, CEI published Guide 31-56, first edition, file 7527 "Constructions for explosive atmospheres due to the presence of combustible dusts – Guide to the application of CEI EN 61241-10 (CEI 31-66)".
In July 2004, CENELEC published standard EN 61241-10 "Electrical apparatus for use in the presence of combustible dust Part 10: Classification of areas where combustible dusts are or may be present" which CEI transposed as national standard CEI EN 61241-10 (CEI 31-66), first edition, file 8290, dated May 2006 "Electrical apparatus for use in the presence of combustible dusts – Part 10: Classification of areas where combustible dusts are or may be present".
In October 2007, CEI published Guide CEI 31-56, file 9049C (consolidated edition) including variants V1 of 2006 (file 8102) and V2 of 2007 (the latter published only by means of communication on CEINFORMA).
In August 2008, CENELEC published standard EN 60079-10-2 "Explosive atmospheres Part 10-2: Classification of areas – Combustible dust atmospheres", which CEI transposed as national standard CEI EN 60079-10-2 (CEI 31-88), first edition, file 10149, dated January 2010 "Explosive atmospheres – Part 10-2: Classification of areas – Explosive atmospheres due to the presence of combustible dust".
In September 2012, CEI published Variant V1 (file 12214) to Guide CEI 31-56, file 9049C, application of standard CEI EN 60079-10-2 (CEI 31-88), first edition. It should be remembered that standard CEI EN 61241-10 (CEI 31-66) for combustible dusts and standard CEI EN 60079-10 (CEI 31-30) for flammable gases, vapours and mists are indicated as a reference for the classification of places with danger of explosion by Legislative Decree 81/08, in Note 3 of the Guide CEI 31-56, file 9049C. 81/08, in Note 3 of Annex XLIX; these standards are now replaced respectively by standard CEI EN 60079-10-2 (CEI 31-88) and standard CEI EN 60079-10-1 (CEI 31-87), which must be understood as their replacement in the light of the evolution of the Rule of Art (see art.28, paragraph 3 of Legislative Decree 81/08).
In March 2015, CENELEC published the ATEX standard EN 60079-10-2 "Explosive atmospheres Part 10-2: Classification of areas – Explosive dust atmospheres", second edition, which CEI transposed as the national standard CEI EN 60079-10-2 (CEI 31-88), second edition, file 15168, dated October 2016 "Explosive atmospheres – Part 10-2: Atex classification of areas – Explosive dust atmospheres".