Division 2.5.5 Where hazards arise as a result of failures of functions of a technical system, without prejudice to points 2.5.1 and 2.5.4, the following ... design targets shall apply to those failures:F1 F2

United Kingdom

(a)
where a failure has a credible potential to lead directly to a catastrophic accident, the associated risk does not have to be reduced further if the frequency of the failure of the function has been demonstrated to be highly improbable.
(b)
where a failure has a credible potential to lead directly to a critical accident, the associated risk does not have to be reduced further if the frequency of the failure of the function has been demonstrated to be improbable.

The choice between F3catastrophic accident or critical accident shall result from the most credible unsafe consequence of the failure.

Annotations

F1: Substituted by Commission Implementing Regulation (EU) 2015/1136 of 13 July 2015 amending Implementing Regulation (EU) No 402/2013 on the common safety method for risk evaluation and assessment (Text with EEA relevance).
F2: Word in Annex 1 points 2.5.5-2.5.8 omitted (E.W.S) (31.12.2020) by virtue of The Rail Safety (Amendment etc.) (EU Exit) Regulations 2019 (S.I. 2019/837), regs. 1, 16(18)(f); 2020 c. 1, Sch. 5 para. 1(1); and omitted (N.I.) (31.12.2020) by virtue of The Rail Safety (Amendment etc.) (EU Exit) Regulations 2019 (S.I. 2019/837), regs. 1, 21(18)(f); 2020 c. 1, Sch. 5 para. 1(1)
F3: Words in Annex 1 point 2.5.5 substituted (E.W.S) (31.12.2020) by The Rail Safety (Amendment etc.) (EU Exit) Regulations 2019 (S.I. 2019/837), regs. 1, 16(18)(ff) (as inserted by S.I. 2019/1310, regs. 1(2)(c), 7(4)(g)(vi)); 2020 c. 1, Sch. 5 para. 1(1); and substituted (N.I.) (31.12.2020) by The Rail Safety (Amendment etc.) (EU Exit) Regulations 2019 (S.I. 2019/837), regs. 1, 21(18)(ff) (as inserted by S.I. 2019/1310, regs. 1(2)(c), 7(7)(g)(vi); 2020 c. 1, Sch. 5 para. 1(1))