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Practical Process Safety
Take Your Medicine. A How-To Prescription for Practical Process Safety, Using Hazard Identification, Risk Assessment, Corporate Risk Policy, Consistent Implementation, Thorough Training and Continuous Revaluation—with Help from Harmonizing Standards and New Technical Tools
05/13/2009
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Enlightening Litigators, Too
Besides changing the old attitudes of their colleagues, engineers willing to discuss and document process safety efforts openly must also convert their firms’ attorneys. “We’re still seeing some hesitancy on the part of the legal community about putting an official stamp of approval on a risk matrix because they’re worried about the exposure of a potential plaintiff using that information,” says Campbell. “It’s taking awhile, but even the lawyers are becoming convinced that it’s a more defensible position if you can show you have a consistently applied RA combined with a risk matrix that puts you in the same ballpark as the rest of your industry.”
Better Safety Tools
While audits, assessments, standards compliance specifications, training and consistent implementation all contribute to better process safety, there also are many improved and safety-certified tools that can help users too. Besides safety-certifying individual devices, organizers also are developing certifications for larger systems based on operator tasks and equipment and system life cycles. Also, TÜV Rhineland’s Functional Safety Program is training hundreds of functional safety experts who can advise their colleagues and other users on safety issues and requirements.
“In past years, the effort was to get safety PLCs certified, and most users have these now. The next step was to develop tools that make it easier for equipment to apply safety standards, so safety life-cycle devices were developed that have more intelligence in their boxes,” says Fialkowski. “They include self-documenting tools with paper trails based on today’s configuration that document what was done, when, and who did it. This enables checks and balances of prior inspections that can aid compliance and safety. We’re also seeing more configuration out in the field, and these documenting tools can help show what bypasses were made, what was done in a system’s bowels and show resulting feedback. This brings remote adjustments up to the management level and helps further minimize human error.”
Likewise, Fialkowski adds that online proof testing is emerging now that allows users to test devices more often. Similar to partial-stroke valve testing, online proof testing allows users in the control room to order a transmitter via a fieldbus to bypass and test a transmitter, and not have to worry as much about tripping their plant.
Similarly, Yokogawa Corp. of America reports that its Pro-Safe RS software examines data coming into its DCS from I/O points via its Vnet/IP network and actively watches for “excursions out of tolerance” to help users monitor their systems and improve overall safety.
Staying Aware
While eternal vigilance is well-known as the price of freedom, it’s also the coin for other crucial items, including long-term process safety.
Campbell explains that another reason some users ironically resist new process safety techniques is because they’ve been successful with older methods. “It’s hard to quantify, but sometimes people rationalize dragging their feet on process safety because they haven’t had a blown heater in 30 years,” he says. “A given facility may have had few or no major incidents in many years, and so they kind of come to believe that an accident can’t happen to them. These users must be reminded that complying with OSHA’s PSM rules is not optional. In these cases, process safety is more psychological than technological, and so it can help to merge an application or facility’s safety rules with its reliability requirements.”
Likewise, Summers reports that after performance-based processes based on RAs emerged in the 1990s, they evolved into quality-based processes that became even more highly analytical. “The problem is that numbers can become a crutch if too much faith is placed in them,” she explains. “Sometimes excessive belief in mathematics can cause users to hide behind requirements that are too broad and don’t provide the functional safety originally needed to prevent an accident. People can forget the actual uncertainty in their data and the limits of what they’re considering in their analyses, and this can cause an artificial sense of security that their safety system must be as good they believe it is. However, when we’re talking about uncertainty, the odds can play against us because what we’re routinely worried about, such as productivity and uptime, can negatively affect safety.”
Proper Process Safety Procedure and PlanningA useful process safety project includes several essential parts. Though they sometimes go by different names, here are the main steps included in most thorough safety evaluation, planning and implementation efforts.1. Secure genuine commitment from top management to process safety effort.2. Recruit and assign a cross-functional team with members from process engineering, process operators, mechanical and electrical staffers, instrument and controls people, IT department and management as needed.3. Go though hazardous operability (hazop) process and look at deviations from normal operations for each process unit and every covered process in the facility.4. Whenever a credible cause and consequence of sufficient magnitude is found, conduct a risk assessment (RA) of it to evaluate its severity and frequency. RAs can use traditional qualitative methods, such as risk graphs, and/or semi-quantitative techniques, such as layer of protection analyses (LOPAs).5. Use RAs and/or LOPAs in conjunction with company’s corporate risk guidelines to establish acceptable risk levels for devices and processes, and assign safety integrity levels (SILs) for each applicable device, loop, process or application.6. Check if existing safety functions are enough to handle RA issues and SILs identified. If they’re sufficient, then document them. If they’re inadequate, then identify gaps in existing safety system and seek to fill them.7. Incorporate safety requirements into functional safety plan and specifications.8. Seek to move beyond safety for individual devices to developing performance-, task- and life-cycle-based safety capabilities.9. Install, maintain and continuously reevaluate and update process safety solutions according to a specific schedule. |
Primary Process Safety Organizations and Websites
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