# Commission Implementing Regulation (EU) No 402/2013 of 30 April 2013 on the common safety method for risk evaluation and assessment and repealing Regulation (EC) No 352/2009 (Text with EEA relevance), Division 2.4.2: A reference system shall satisfy at least the following requirements:

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

(a)it has already been proven in-use to have an acceptable safety level in the United Kingdom;
(b)it has similar functions and interfaces as the system under assessment;
(c)it is used under similar operational conditions as the system under assessment;
(d)it is used under similar environmental conditions as the system under assessment.

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Source: https://www.legislation.gov.uk/eur/2013/402/annex/I/division/2/division/2.4/division/2.4.2 (the official version)
Page: https://openlegislation.uk/eu-regulation-2013-402/annex-I/division-2/division-2.4/division-2.4.2
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.