This article was printed in CONTROL's May 2009 edition.
By Jim Montague, Executive Editor
Open wide. It isn’t a spoonful of sugar. But doing process safety right doesn’t have to be cod liver oil either.
For instance, planning to put safety instrumented systems (SISs) on hundreds of process heaters at 13 U.S. refineries and three in Europe might seem extremely difficult, if not close to impossible. However, engineers at ConocoPhillips in Houston just did what they usually do, and took on the problem step by step.
“We use the same approach as OSHA’s PSM and ISA S84 standards. Starting three years ago, we established an in-house standard and set a timetable for compliance by 2012,” says John Campbell, ConocoPhillips’ principal instrumentation and controls engineer. “So far, this project is going well. Some heaters are already in compliance, while others will need renovation and capital expenditures. It’s not going as fast as we hoped, but we’re getting there.”
The U.S. Occupational Health and Safety Administration’s Process Safety Management (PSM) standard 29 CFR 1910.119 is available online. The International Society of Automation’s S84 standard parallels the International Electrotechnical Commission’s 61511 standard, except for a now-infamous grandfather clause that allows U.S. facilities to keep operating non-compliant processes with otherwise safe records.
“Our in-house standard covers requirements for how our refineries should shut down their process heaters, and so we tried to follow PSM at the 30,000-ft level, S84 for SISs at the 3,000-ft level, and the American Petroleum Institute’s 556 standard for process heaters at tree-top level,” explains Campbell. “We think involving all these levels gives our standard the best coverage.”
One potential snag in ConocoPhillips’ project is that each plant is responsible for its own process heater renovations, and each will be judged on a pass/fail basis in 2012. Campbell acknowledges that there’s been some foot dragging, too. “This is why it’s so important to have the man at the top say, ‘This is your deadline, and you’re going to be judged if you’ve met it or not.’”
Campbell adds that all the major oil, gas and other process industry players have faced these safety issues for years, and not just with instrumentation, but with all kinds of piping, valves, rotating equipment, vessels and other technologies. “I knew a guy in a working group that had been dealing with process safety for awhile, and thought they had a good PSM culture. But then he walked into the plant, and the first thing the service tech asked was, ‘Why are we doing all this safety stuff?’”
Just as equipment and systems need regular process safety check-ups, Campbell says process personnel need regular evaluations so anti-process safety prejudices and unsafe practices don’t become widespread. “It takes plenty of manpower and time, but good PSM always relies on regular inspection and testing. Even if you repeatedly find nothing wrong and think you can slack off, you still need to do it.”
“My advice to other process safety folks is, if you’re feeling overwhelmed, then find a smaller piece of your process that you can handle, do it and then move on to the next one,” adds Campbell.
Common Sense and Consistency
A practical approach to process safety begins with thinking about what you’re going to do after an accident happens and what will be expected of you, according to Angela Summers, Ph.D, P.E., president of Sis-Tech Solutions, a process safety consulting firm in Houston, Texas. “If you don’t have an SIS in place, you’ll be asked why after an incident occurs,” she says.
Summers explains that a check of past process incidents shows they don’t occur in applications with a working SIS. “Incidents happen where an SIS wasn’t put in, where it was broken or where it was defeated by its users,” she says. “This generation believes its technology is better than it was 50 years ago, but back then, process technologies were simpler, more separated and less flexible, and so there were less potential failures. As these technologies continue to grow more integrated, we need to more actively and aggressively manage that integration.”
Consequently, the first step in creating or renovating a process safety system is to look at the process application, identify any loss-of-containment events that could cause a fatality or serious injury, determine those events’ initiating causes and frequency, look at available protection layers, examine how to reduce the frequency of any events, such as by implementing a well-designed and managed SIS [see “Proper Process Safety Procedure and Planning” at the end of this article]
“Anyplace where an event like this could happen will need an SIS that’s independent of the control system and part of a rigorous mechanical integrity program,” says Summers. “Luckily, everything you need to implement an SIS is well within the expertise of any well-qualified process engineer.”
While some users believe it’s enough to have an SIS that complies with prevailing standards, Summers says it’s not enough. “Standards can allow you to hang yourself if you don’t recognize where your system is still vulnerable. So companies must also build their own prescriptive way of doing safety and make their SIS as idiot-proof as possible by ensuring that operators can’t defeat it, and by making certain that users test, maintain, report, respond and otherwise interact with it in the same way every time and in every setting.”