Boiler, furnaces and other burning equipments such as thermal reactors for sulphur recovering in oil refineries are considered high-risk areas within the process industry. Extreme operating conditions and the processing of hazardous materials result in wide safeguarding measures applicable to prevent accidents. One of the best known and widely accepted technical solutions concerns the use of safety-related systems implemented through programmable electronic system (PES) technology.
Current functional safety standards of the International Electrotechnical Commission (IEC), like IEC 61508 and IEC 61511 control the design of these technical solutions. A new risk-based approach is adopted to reduce the hazards. They include technology-oriented requirements and their ‘adequate’ implementation for tailoring the instrumented systems ‘fit-to-purpose’ to the needs of process safety. This approach has significant safety and economic benefits as it is intended to be demonstrated by this paper. However, to obtain functional safety this approach demands more management, competency and planning than the prescriptive requirements of original standards.
This paper presents a case study about the identification of safety functions in a burner management system (BMS) and the application of the two main concepts of functional safety: safety integrity level (SIL) and safety lifecycle (SLC). Since this type of control systems shares process control and safeguarding functions, the combination of risk-based concepts with original approach is required during the design.
Part of the objectives of this technical paper alternative is to evaluate architectures in detail engineering looking at the most effective cost-benefit ratio. The benefits obtained are the achievement of the safety requirements demanded after analysing the process risks with the best cost-reliability compromise. © 2015 Risknowlogy. All Rights Reserved.
- Authors: Jorge Sánchez Fontao, Paul Johannes H. Tullemans
- Published: April 2015
- Words: 4950