Emerson’s Mike Boudreaux alerted me to a great article comparing safety instrumented system architectures. The ISA InTech article, Centralized or distributed process safety compares and contrasts centralized, distributed, and hybrid safety systems. Centralized systems have a single logic solver with all safety I/O routed and hardwired back to it. Distributed systems locate the logic controllers [...]
I had the chance to catch up with Emerson’s Riyaz Ali at the Emerson Exchange last month in Nashville. You may recall Riyaz from many process safety-related posts. In his conversations with process automation and safety professionals, he has been encountering some misconceptions he hoped we could clear up in this post. These misconceptions surround [...]
I saw an email string with a question asking if it’s possible to detect all possible failure modes in a safety valve if very intensive and intrusive tests, such as full-stroke testing, leak testing, etc. are performed. Would it be conceivable to use 100% proof test coverage when performing full repair upon detection of a [...]
Exida’s Dr. William Goble and Emerson’s Afton Coleman presented Addressing Partial Stroke Testing Fears – Avoiding False Trips / Risk Through… Their abstract: It is not uncommon for some users to perform partial stroke testing (PST) using cumbersome mechanical or pneumatic devices, or avoid PST altogether due to fears of spurious trip. This workshop addresses [...]
Update and bump: Here is the link to Andy’s paper, The importance of a clear Safety Requirements Specification as part of the overall Safety Lifecycle, which is now posted. Original May 2011 post: Emerson’s Andy Crosland, a process safety expert, will be presenting a paper at the Safety Control Systems Conference, May 24-26 in Manchester, [...]
The language of process safety is filled with its own jargon. Architectures are described as 1oo1, 1oo2, 2oo2, 2oo3, etc. The “oo” means “out of”. So, 1oo1 means one-out-of-one. William M. Goble and Harry Cheddie wrote a book, Safety Instrumented Systems Verification – Practical Probabilistic Calculations, to explain how to do probabilistic calculations based on [...]
As we did with the recent energy efficiency post, I wanted to highlight a few key points made in past IEC 61511 safety lifecycle-related posts. This global safety standard provides a performance-based methodology to plan and execute your process safety efforts through the lifecycle of your manufacturing process. A great place to begin is with [...]
I saw a great article from exida‘s Dr. Peter Clarke, Setting the Standard, on how process plants can benefit through proper and careful adoption of the IEC 61511 global safety standard. It’s perhaps the best primer I’ve seen in a while on the safety lifecycle and the role of safety instrumented systems. He describes the [...]
Over at the Process Safety Management (1000+) LinkedIn group is a provocative question, Personal Safety & Process Safety – does management really confuse the two? Do engineers confuse them? The thread began a month ago and has 77 responses and 4 “likes” to date. The person who began the thread points to recent accidents where [...]
Furnaces, fired heaters, boilers and other process units requiring burners to manage are common across many process industries such as refining, chemicals, petrochemicals, and power. Recognizing and reacting to flame instability is critical since a flameout condition is dangerous and often results in a costly shutdown initiated by the burner management system. Emerson’s John Miller, [...]
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