Managing the Lifecycle of Safety Instrumented Systems

20140403-153458.jpgA tremendously experienced panel in functional safety included Dipl.-Ing.(FH) Senior Project Manager, Josef Neumann TÜV NORD Systems, Dr. William Goble Principle Partner, Exida, Russell Cockman Consultant SIS, Emerson, Nicolas Menet, Business Development Manager for Emerson’s Fisher Valves family of products, and Aart Pruysen Director Approvals, Emerson. The experts panel’s abstract:

Maintaining Safety Integrity is vital if your SIS is to protect your people, assets and the environment. Emerson’s Smart SIS approach continuously monitors the readiness of sensors, logic solvers, and final control elements to execute their safety functions, but can these smart diagnostics prevent mistakes by people? This open session will focus on managing your safety instrumented system, whilst ensuring compliance to IEC 61511, and provide the opportunity to discuss with our experts topics such as Certification, Validation, Proof Testing, effect of Online Diagnostics on SIL Calculations, Change Management, as well as how to integrate these features with the latest extension of Electronic Marshalling to DeltaV SIS (Safety Instrumented System).

Emerson’s Andy Crosland emceed the panel and opened with a question to Josef about challenges he sees with companies address the IEC 61511 safety lifecycle.

Bill Goble sees the part of the safety lifecycle that cause the most problems is the ongoing proof testing and record keeping.

Russell added you must record what you do in proof testing because you must have evidence that you are following the safety lifecycle you established.

A question came in about who owns the safety lifecycle and do independent protection layer? The documentation requirements are clear. When asked if proof testing was required for independent layers of protection (ILP), Bill asked rhetorically, “How will you know if it works?” Josef added that the company must own the process and assign an accountability process. Russell added that the safety requirement specification (SRS) should be the vehicle for adding the ILP proof test requirements.

A question about the balance of probability of failure on demand (PFD) with other areas around safety. It should be about 5% instead of 50% of the focus. It’s important, but only one of many factors.

Russell raised the issue of the importance of competency. Being able to understand the report, safety manual, proof test intervals, etc. for the final control elements, sensor, and logic solver components in a safety instrumented function.

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