Then it was off to Triconex’s SIS roundtable, which wasn’t. A roundtable is usually a few experts with an audience listening to punditry and wind. This definitely wasn’t that.
Almost forty people, the vast majority end users in the chemical and refining industries, from companies like Shell, Chevron, ChevronPhillips, Lyondell and others gathered for it.
As each previously contributed question was displayed on the screen, the end users took turns trying to answer them. One of the questions that kept coming back in several iterations was about competency. How do you define competency, how do you define who is a “competent person” and a “senior competent person” as called for in IEC standard 61511 and ANSI/ISA84.00.01-2004?
“We’re sending our people through the Tricon course, does that qualify?” was the answer from one participant. “Then we validate them through test procedures we have in place, because we have two people dedicated to SIS,” she concluded.
“Our hourly people have to pass safety systems training,” another participant began, “but one person will do a job differently than another. With a step-by-step instruction set you don’t have variation. Competence is important, and so is consistency,” he said.
Another participant noted that TŰV certifies competence. “Yes,” argued another, “but if they’re certified but they can’t size an orifice, then what?” Yet another participant pointed out that more and more countries are going for certification, while another commented, “the competency programs out there aren’t looking at the instrument engineer part of the equation.”
“I’m not sure training is the only way,” began another participant. “We’ve had ‘trained’ people with five years’ experience force a global point instead of a local point and shut the whole unit down. Then there’s that ‘pucker factor’ if you’ve been trained but nothing’s gone wrong for years, and then alarms start to sound. What do you do?”
Most of the participants appeared to be considerably more conservative in their outlook than many SIS vendors would like.
“I understand the failure modes of a solenoid valve,” said one participant from a major refinery, “and I don’t understand the failure modes of smart positioners. I’m not satisfied that smart positioners don’t have issues that need working out.”
“We’re planning to,” was the response to the question of who is using analog outputs with smart positioners. “Are you people really comfortable with the failure modes on smart positioners,” argued another participant, “I keep trying,” he went on, “to get vendors to give me data, but they give me lots of numbers and no failure data.”
“Safety fieldbus won’t get us any advantage I can see,” said one engineer. “Diagnostics are available from HART and we’ve all got that, so why do it?”
But on the other hand, many of the participants shared their reluctance to use digital communications buses like HART, Modbus, TCP, and OPC communications to perform SIS functions from bypasses to even closed loop control. “You can use HART to initiate partial stroke testing,” one engineer bravely began, but he was nearly shouted down by people who said that HART was too slow, and not safe enough.
The discussion was passionate, lively, informed, and showed the level of detailed thought, planning and engineering necessary to implement the SIS standards. This is not “Plug and Play.”