Safety instrumented system (SIS) design requires care and expertise. This expertise includes not only a good knowledge of what instrument best meets the needs of the application, but also knowledge of functional safety standards. The ANSI/ ISA 84.00.01/ IEC 61511, Functional Safety for the Process Industries, requires careful justification of instrumentation.
The equipment used in SISs must be chosen based on either IEC 61508 certification to the appropriate safety integrity level (SIL) or justification based on "prior use" criteria (Part 1, Section 11.5.3). Unfortunately, the IEC 61511 standard does not give specific details as to what prior use really means. Most agree, however, that
Log in to view this article.
Not Yet A Subscriber? Here are Your Options.
1) Start a FREE TRIAL SUBSCRIPTION and gain access to all articles in the current issue of Hydrocarbon Processing magazine.
2) SUBSCRIBE to Hydrocarbon Processing magazine in print or digital format and gain ACCESS to the current issue as well as to 3 articles from the HP archives per month. $409 for an annual subscription*.
3) Start a FULL ACCESS PLAN SUBSCRIPTION and regain ACCESS to this article, the current issue, all past issues in the HP Archive, the HP Process Handbooks, HP Market Data, and more. $1,995 for an annual subscription. For information about group rates or multi-year terms, contact email Peter Ramsay or call +44 20 3409 2240*.
*Access will be granted the next business day.