A semi-quantitative approach for verification of Safety Integrity Level requirements

• Autorzy: Abrahamsen E. B. , Røed W.
• Języki publikacji: EN

Abstrakty

EN

A Safety Integrity Level (SIL) is a measure of performance required for a safety instrumented function. The IEC 61508/61511 standards define four safety integrity levels, SIL1 to SIL4, where SIL4 is the level with the most stringent requirements. For each safety integrity level there are many design requirements, including requirements for the probability of failure on demand (PFD). Verification of the required failure probabilisty is usually based on a quantitative analysis. In this paper we argue that such an approach is better replaced by a semi-quantitative approach. The approach acknowledges that the PFD requirement for a safety function cannot be adequately verified only by reference to an assigned probability number. There is a need for seeing beyond the probability number. The key aspect to include is related to uncertainty. Such an aspect is of ten ignored in verification of a safety integrity level. The offshore oil and gas industry is the starting point, but the discussion is to large extent general.

Słowa kluczowe

EN

safety integrity level; probability of failure on demand; uncertainty

• Wydawca: Polskie Towarzystwo Bezpieczeństwa i Niezawodności
• Czasopismo: Journal of Polish Safety and Reliability Association
• Rocznik: 2010
• Tom: Vol. 1, No. 1
• Strony: 1--6
• Opis fizyczny: Bibliogr. 11 poz., rys., tab.

Twórcy

autor

Abrahamsen E. B.

• University of Stavanger, Stavanger, Norway

autor

Røed W.

• Proactima, Stavanger, Norway

Bibliografia

• [1] Abrahamsen, E. B., Aven, T. & Iversen, R. S. (2009). An integrated framework for safety management and uncertainty management In petroleum operations. Journal of risk and reliability. To appear.
• [2] Aven, T. (2008). Risk analysis – Assessing uncertainties beyond expected values and probabilities. Wiley. NJ.
• [3] Brown, S. (2000). Overview of IEC 61508 – Design of electrical/electric/programmable electronic safety-related systems. In Computing and Control Engineering Journal 11: 6-12.
• [4] Cabinet Office. (2002). Risk: improving government’s capability to handle risk and uncertainty. Strategy unit report. UK.
• [5] Flage, R. & Aven, T. (2009). Expressing and communicating uncertainty in relation to quantitative risk analysis. Risk & Reliability – Theory & Application 2009; 2(13): 9-18.
• [6] Hauge, S., Lundteigen, M. A., Hokstad, P. & Håbrekke, S. (2010). Reliability prediction method for safety instrumented systems. PDS method Handbook 2010 edition. SINTEF, ISBN 978-82-14-04850-6.
• [7] IEC – International electrotechnical commission. (2003a). IEC 61508. Functional safety of electric/electronic/programmable electronic safety-related systems. International Electrotechnical Commission; Geneva.
• [8] IEC - International electrotechnical commission. (2003b). IEC 61511. Functional safety – safety instrumented systems for the process industry. International Electrotechnical Commission; Geneva.
• [9] OLF – The Norwegian oil industry association (2004). OLF-070. Application of IEC 61508 and IEC 61511 in the Norwegian petroleum industry. Technical report, The Norwegian Oil Industry Association, Stavanger, Norway.
• [10] Renn, O. (2008). Risk governance: coping with uncertainty in a complex world. London: Earthscan.
• [11] Smith, D. J. & Simpson, K. G. L. (2005). Functional safety – s straightforward guide to applying the IEC 61508 and related standards. Burlington, UK.: Elsevier.