What is BS EN 61508-1 - Functional safety of programmable electronic safety-related systems about?
BS EN 61508-1 is the first part of the BS EN 61508 multi-series. This European standard sets out a generic approach for all safety lifecycle activities for systems comprised of electrical and/or electronic and/or programmable electronic (E/E/PE) elements that are used to perform safety functions.
BS EN 61508-1 covers those aspects to be considered when electrical/electronic/programmable electronic (E/E/PE) systems are used to carry out safety functions.
In particular, BS EN 61508-1:
- Applies to safety-related systems when one or more of such systems incorporates electrical/electronic/programmable electronic elements
- Is generically based and applicable to all E/E/PE safety-related systems irrespective of the application
- Covers the achievement of a tolerable risk through the application of E/E/PE safety-related systems, but does not cover hazards arising from the E/E/PE equipment itself (for example electric shock)
- Applies to all types of E/E/PE safety-related systems, including protection systems and control systems
- Is mainly concerned with the E/E/PE safety-related systems whose failure could have an impact on the safety of persons and/or the environment; however, it is recognized that the consequences of failure could also have serious economic implications and in such cases, BS EN 61508-1 could be used to specify any E/E/PE system used for the protection of equipment or product
Note: BS EN 61508-1 does not cover E/E/PE systems where:
- A single E/E/PE system is capable on its own of meeting the tolerable risk
- The required safety integrity of the safety functions of the single E/E/PE system is less than that specified for safety integrity level 1 (the lowest safety integrity level in BS EN 61508-1).
Who is BS EN 61508-1 - Functional safety of programmable electronic safety-related systems for?
BS EN 61508-1 on the functional safety of electrical/electronic/ programmable electronic safety-related systems is useful for:
- Safety engineers
- Manufacturers of electrical, electronic and programmable electronic safety devices
- Suppliers of electronic safety devices
- Regulatory bodies
- Occupational health and safety officers
Why should you use BS EN 61508-1 - Functional safety of programmable electronic safety-related systems?
Systems comprised of electrical and/or electronic elements have been used for many years to perform safety functions in most application sectors. Computer-based systems (generically referred to as programmable electronic systems) are being used in all application sectors to perform non-safety functions and, increasingly, to perform safety functions. If computer system technology is to be effectively and safely exploited; it is essential that those responsible for making decisions have sufficient guidance on the safety aspects on which to make these decisions.
BS EN 61508-1 stipulates the general requirements for electrical, electronic and programmable electronic safety devices. BS EN 61508-1 covers the safety systems of electrical equipment and their components that could have an impact on the safety of people and the environment if they fail. BS EN 61508-1 also applies to protection and control systems and helps organizations identify hazards to improve overall equipment safety in the workplace.
BS EN 61508-1 explains the objectives and requirements that should be taken into account when it comes to the management of functional safety.
Overall, BS EN 61508-1 defines the overall safety life cycle requirements such as hazard and risk analysis, maintenance planning, and verification before looking at the best practice assessments of functional safety.
A Commented Version (CMV) of this standard series is available here. Please note, the CMV of the standard is not adopted, and therefore doesn’t contain an additional national foreword, or national annex that might be contained in the BS adoption of the standard. However the IEC text that forms the content of the standard is identical to the BS adoption of the standard.
Commented Versions (CMVs) are specialized publications featuring detailed commentary from technical experts on the major changes between the new edition of a standard and the previous one. Comments may include an explanation for the changes as well as information on the impact of these changes on the application and usability of the standard.

