prEN IEC 61508-2:2025

This part of the IEC 61508 series
a) is intended to be used only after a thorough understanding of IEC 61508-1, which provides the overall framework for the achievement of functional safety;
b) applies to any safety-related system, as defined by IEC 61508-1, that contains at least one electrical, electronic or programmable electronic element;
c) applies to all elements within an E/E/PE safety-related system (including sensors, actuators and the operator interface);
d) specifies how to refine the E/E/PE system safety requirements specification, developed in accordance with IEC 61508-1 (comprising the E/E/PE system safety functions requirements specification and the E/E/PE system safety integrity requirements specification), into the E/E/PE system design requirements specification;
e) specifies the requirements for activities that are to be applied during the design and manufacture of the E/E/PE safety-related systems (i.e. establishes the E/E/PE system safety lifecycle model) except software, which is dealt with in IEC 61508-3 (see Figures 2 to 4). These requirements include the application of techniques and measures that are graded against the safety integrity level, for the avoidance of, and control of, faults and failures;
f) specifies the information necessary for carrying out the installation, commissioning and final safety validation of the E/E/PE safety-related systems;
g) does not apply to the operation and maintenance phase of the E/E/PE safety-related systems – this is dealt with in IEC 61508-1 – however, IEC 61508-2 does provide requirements for the preparation of information and procedures needed by the user for the operation and maintenance of the E/E/PE safety-related systems;
h) specifies requirements to be met by the organisation carrying out any modification of the E/E/PE safety-related systems;
NOTE 1 This part of IEC 61508 is mainly directed at suppliers and/or in-company engineering departments, hence the inclusion of requirements for modification.
NOTE 2 The relationship between IEC 61508-2 and IEC 61508-3 is illustrated in Figure 4.