What is IEC61511?

IEC 61511 Ed2 is the Functional Safety standard for the process industry

One of the objectives of IEC 61508 is to provide a framework for the development of industry sector international standards regarding functional safety. This ensures consistency with the approach and underlying principles laid down in IEC 61508 whilst allowing a more streamlined set of requirements to be tailored to a specific industry. Hence, IEC 61511 is the international functional safety standard for the process industry.

IEC 61511 is entitled ‘Functional Safety – Safety instrumented systems for the process industry sector’ and is published in three parts:

· Part 1 (normative): Framework, definitions, system (hardware and software) requirements

· Part 2 (informative): Guidance on how to apply Part 1

· Part 3 (informative): Guidance on how to determine SIL requirements

The standard is written specifically for those who deal with process application ‘Safety Instrumented Functions’ (SIFs), e.g., SIL determination analysts, SIF specifiers, system suppliers, engineering procurement contract (EPC) companies, installers, operators and maintainers. In terms of the Safety Instrumented System (SIS) design, IEC 61511 requires the component devices to be pre-compliant with IEC 61508 or be selected on a ‘prior use’ basis, and focuses on the system lifecycle activities needed to meet and maintain the functional safety requirements.

The 61508 Association includes many members who are specifically involved in the process industry and we are active in producing a range of guidance for those working in this sector. Our members reflect the entire equipment supply chain, consultants and process plant end-users, and we have particularly good relationships with regulators in the process industry. Our guidance often deals with the practical challenges that are not covered in standards such as how to deal with legacy systems, how process and machine safety come together, combining control and safety systems, etc. Please see downloads for more information.

Revision Status as of 18th October 2017

The final vote on the issue of IEC 61511.Ed2 was taken by 20 countries, and is available from the IEC Website, together with a separate corrigendum.

IEC 61511 Ed2 requires the corrigendum to be incorporated into the standard before it can be approved by CENELEC. This approval is required before it can become a BS.EN.IEC document.

However, as far as the HSE are concerned, Ed 2 with the separate corrigendum is considered “Best Practice”. Therefore, users should comply with Part 1 (the normative part).