Emergency Shutdown Valves: A Functional Safety Approach to Selection
By Chemical Engineering |
The relationship between valve selection and safety certification still causes confusion. A focus on functional safety can help to elucidate
Among the many varied viewpoints on the topic of emergency shutdown (ESD) valves, there are several aspects that continue to spark discussion and cause confusion due to a lack of complete clarity, including the relationship between valve selection and safety certification. In this article, we aim to clarify a few of the most misunderstood points associated with the selection of ESD valves. And in doing so, we hope to bring greater recognition to the concept of functional safety, which is associated with the safety integrity level (SIL) standards laid out by the International Electrotechnical Commission (IEC; Geneva, Switzerland; www.iec.ch):
IEC 61508 (Functional Safety of Electrical/Electronic/Programmable Electronic Safety-Related Systems)
IEC 61511 (Functional safety – Safety instrumented systems for the process industry sector)
Functional safety is a much broader set of concerns than the question of which valves to select.
Certification has been a key issue of confusion recently: many people think “a SIL 3 certificate for valves is a must; likewise for a solenoid valve.” Still,…