Lessons Learned in IEC 61508 Assessments
Author : Paul Reeve
20 November 2009
Sira has conducted numerous assessments against IEC 61508, working mainly to Safety Integrity Level (SIL) 2 or 3. In this paper we present some of the lessons that Sira has learned and offer advice to those either specifying and using SIL-rated systems or those requiring certification for components intended to be used by safety functions.
Lessons Learned in IEC 61508 Assessments
Three main parts of the standard are covered:
1. Functional Safety Management
2. Hardware
3. Software
For end users, it is vital to produce a clear and comprehensive requirements specification based on an analysis of the specific safety hazards associated with the machine or process. After the safety-related system has been commissioned, what are the implications for the end user of owning, operating and maintaining such a system in order to ensure its continued SIL compliance?
For equipment developers, the relationship between the management of functional safety (a requirement for all safety-related systems) and the ISO 9001 quality system is explained and the common pitfalls are presented. Advice is offered on how to establish a safety culture in the development team and how the rigour of the development processes affects the SIL capability that can be claimed. These are subjects that need a commitment and resolve from senior management if compliance with the standards is the desired outcome.
For the hardware and software design, Paul Reeve shall describe some of the common problems encountered by manufacturers of products ranging from simple electromechanical devices through to complex electronics in their attempts to comply with IEC 61508 when it is faced for the first time.
This paper will be presented at HazardEx 2010
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