prEN IEC 61508-2:2025
(Main)Functional safety of electrical/electronic/programmable electronic safety-related systems - Part 2: Requirements for electrical/electronic/programmable electronic safety-related systems
Functional safety of electrical/electronic/programmable electronic safety-related systems - Part 2: Requirements for electrical/electronic/programmable electronic safety-related systems
Funktionale Sicherheit sicherheitsbezogener elektrischer/elektronischer/programmierbarer elektronischer Systeme - Teil 2: Anforderungen an sicherheitsbezogene elektrische/elektronische/programmierbare elektronische Systeme
Sécurité fonctionnelle des systèmes électriques/électroniques/électroniques programmables relatifs à la sécurité - Partie 2: Exigences pour les systèmes électriques/électroniques/électroniques programmables relatifs à la sécurité
Funkcijska varnost električnih/elektronskih/programljivih elektronskih varnostnih sistemov - 2. del: Zahteve za električne/elektronske/programljive elektronske varnostne sisteme
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Standards Content (Sample)
SLOVENSKI STANDARD
01-april-2025
Funkcijska varnost električnih/elektronskih/programljivih elektronskih varnostnih
sistemov - 2. del: Zahteve za električne/elektronske/programljive elektronske
varnostne sisteme
Functional safety of electrical/electronic/programmable electronic safety-related systems
- Part 2: Requirements for electrical/electronic/programmable electronic safety-related
systems
Funktionale Sicherheit sicherheitsbezogener
elektrischer/elektronischer/programmierbarer elektronischer Systeme - Teil 2:
Anforderungen an sicherheitsbezogene elektrische/elektronische/programmierbare
elektronische Systeme
Sécurité fonctionnelle des systèmes électriques/électroniques/électroniques
programmables relatifs à la sécurité - Partie 2: Exigences pour les systèmes
électriques/électroniques/électroniques programmables relatifs à la sécurité
Ta slovenski standard je istoveten z: prEN IEC 61508-2:2025
ICS:
25.040.40 Merjenje in krmiljenje Industrial process
industrijskih postopkov measurement and control
35.240.50 Uporabniške rešitve IT v IT applications in industry
industriji
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
65A/1165/CDV
COMMITTEE DRAFT FOR VOTE (CDV)
PROJECT NUMBER:
IEC 61508-2 ED3
DATE OF CIRCULATION: CLOSING DATE FOR VOTING:
2025-02-14 2025-05-09
SUPERSEDES DOCUMENTS:
65A/1057A/CD, 65A/1076A/CC
IEC SC 65A : SYSTEM ASPECTS
SECRETARIAT: SECRETARY:
United Kingdom Ms Stephanie Lavy
OF INTEREST TO THE FOLLOWING COMMITTEES: HORIZONTAL FUNCTION(S):
TC 8,TC 9,TC 22,TC 31,TC 44,TC 45,TC 56,TC 61,TC
62,TC 65,SC 65B,SC 65C,SC 65E,TC 66,TC 72, TC
77,TC 80,TC 108,SyC AAL,SyC SM,SC 41
ASPECTS CONCERNED:
Safety
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the final stage for submitting ISC clauses. (SEE AC/22/2007 OR NEW GUIDANCE DOC).
TITLE:
Functional safety of electrical/electronic/programmable electronic safety-related systems -
Part 2: Requirements for electrical/electronic/programmable electronic safety-related systems
PROPOSED STABILITY DATE: 2028
NOTE FROM TC/SC OFFICERS:
electronic file, to make a copy and to print out the content for the sole purpose of preparing National Committee positions.
You may not copy or "mirror" the file or printed version of the document, or any part of it, for any other purpose without
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IEC CDV 61508-2 ED3 © IEC 2025 2 65A/1165/CDV
1 CONTENTS
3 FOREWORD . 5
4 INTRODUCTION . 7
5 1 Scope . 9
6 2 Normative references . 10
7 3 Definitions and abbreviations . 11
8 4 Conformance to this document . 11
9 5 Documentation . 11
10 6 Additional requirements for management of functional safety for E/E/PE system . 12
11 6.1 Objectives . 12
12 6.2 Requirements . 12
13 7 E/E/PE system safety lifecycle requirements . 12
14 7.1 General . 12
15 7.1.1 Objectives and requirements – general . 12
16 7.1.2 Objectives . 13
17 7.1.3 Requirements . 13
18 7.2 E/E/PE system design requirements specification . 15
19 7.2.1 Objective . 15
20 7.2.2 General . 16
21 7.2.3 E/E/PE system design requirements specification . 16
22 7.3 E/E/PE system safety validation planning . 18
23 7.3.1 Objective . 18
24 7.3.2 Requirements . 18
25 7.4 E/E/PE system design and development . 18
26 7.4.1 Objective . 18
27 7.4.2 General requirements . 18
28 7.4.3 Synthesis of elements to achieve the required systematic capability . 21
29 7.4.4 Hardware safety integrity architectural constraints . 22
30 7.4.5 Requirements for quantifying the effect of random hardware failures . 33
31 7.4.6 Requirements for the avoidance of systematic faults . 35
32 7.4.7 Requirements for the control of systematic faults . 36
33 7.4.8 Requirements for system behaviour on detection of a fault . 37
34 7.4.9 Requirements for E/E/PE system implementation . 37
35 7.4.10 Requirements for systematic safety integrity of proven in use elements
36 (Route 2s) . 39
37 7.4.11 Additional requirements for data communications . 40
38 7.4.12 Requirements for diagnostic functions . 42
39 7.5 E/E/PE system integration . 43
40 7.5.1 Objective . 43
41 7.5.2 Requirements . 43
42 7.6 E/E/PE system operation and maintenance procedures . 44
43 7.6.1 Objective . 44
44 7.6.2 Requirements . 44
45 7.7 E/E/PE system safety validation . 45
46 7.7.1 Objective . 45
47 7.7.2 Requirements . 46
IEC CDV 61508-2 ED3 © IEC 2025 3 65A/1165/CDV
48 7.8 E/E/PE system modification . 47
49 7.8.1 Objective . 47
50 7.8.2 Requirements . 47
51 7.9 E/E/PE system verification . 48
52 7.9.1 Objective . 48
53 7.9.2 Requirements . 48
54 8 Functional safety assessment . 49
55 Annex A (normative) Techniques and measures for E/E/PE safety-related systems –
56 control of failures during operation . 50
57 A.1 General . 50
58 A.2 Hardware safety integrity . 51
59 A.3 Systematic capability . 59
60 Annex B (normative) Techniques and measures for E/E/PE safety-related systems –
61 avoidance of systematic failures during the different phases of the lifecycle . 65
62 Annex C (normative) Diagnostic coverage and safe failure fraction . 75
63 C.1 Calculation of diagnostic coverage and safe failure fraction of a hardware
64 element . 75
65 C.2 Determination of diagnostic coverage factors . 76
66 Annex D (normative) Safety manual for compliant items . 78
67 D.1 General . 78
68 D.2 Contents . 78
69 Annex E (normative) Common Cause Failure Analysis (CCFA) . 80
70 E.1 General . 80
71 E.2 Methodology . 80
72 E.3 Propagation of common cause failures . 80
73 E.4 Architecture . 81
74 E.5 Common cause failure analysis . 82
75 E.6 Common cause initiators . 83
76 Bibliography . 84
78 Figure 1 – Overall framework of the IEC 61508 series . 10
79 Figure 2 – E/E/PE system safety lifecycle (in realisation phase). 14
80 Figure 3 – Relationship between and scope of IEC 61508-2 and IEC 61508-3 . 14
81 Figure 4 – Determination of the maximum SIL for specified architecture (E/E/PE safety-
82 related subsystem comprising a number of series elements, see 7.4.4.2.3) . 28
83 Figure 5 – Determination of the maximum SIL for a safety function carried out by a
84 specified architecture (E/E/PE safety-related subsystem comprised of two subsystems
85 X & Y, see 7.4.4.2.4). 31
86 Figure 6 - Architectures for data communication – “white channel” . 41
87 Figure 7 – Architectures for data communication – “black channel” . 41
88 Figure G.1 – Methodology . 80
89 Figure G.2 – Propagation of common cause failures . 81
90 Figure G.3 – Example of an architecture . 82
91 Figure G.4 – Common cause failure analysis . 82
93 Table 1 – Overview – realisation phase of the E/E/PE system safety lifecycle . 14
94 Table 2 – Maximum allowable safety integrity level for a safety function carried out by
95 a type A safety-related element . 26
96 Table 3 – Maximum allowable safety integrity level for a safety function carried out by
97 a type B safety-related element . 27
IEC CDV 61508-2 ED3 © IEC 2025 4 65A/1165/CDV
98 Table A.1 – Faults or failures to be assumed wh
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