By Dan Hebert, PE
Accidents and incidents occur in process plants on a too-regular basis. Why? Is the root cause incorrect and incomplete standards? Or do most accidents occur because mostly correct standards are not implemented as intended? Getting the right answers to these questions is critical because wasting time and money implementing bad standards diverts resources from preventing accidents.
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“Problems occur because standards are not known, are not enforced or are not followed thoroughly. It is one thing to have the theory and another actually to put it in place and have it working,” he adds.
Gene Niewoehner, the director of environmental, health and safety at systems integrator, Maverick Technologies, agrees with Lang. “Safety theories and standards are correct and accurate,” he says. “The theories are based on physics, chemistry and available technologies to control conditions and a series of sometimes unrelated events which can result in catastrophic failure. The safety standards and methodologies used today build layers of protection that guard against potentially harmful events.”
Dr. Bill Goble, co-founder and managing partner of automation safety systems vendor exida and a certified process safety expert, concurs. “Based on the accident reports and accident studies I have read, it appears as if the process safety and alarm management standards are right,” he says.
It’s the Implementation, Stupid
Most process plants preach safety incessantly, but they don’t walk the talk. “The majority of accidents occur because organizations have failed to implement best practices and guidelines on process safety,” observes Edward Naranjo, Ph.D., and product manager at gas and flame detection system vendor General Monitors.
“Despite widespread reference to safety first in corporate mission statements and communications, the changes in culture that basic safety principles entail haven’t sufficiently permeated the entire workforce. Even companies with gilded safety records have gaps in their approach to preventing hazards,” adds Naranjo.
One of the main reasons why implementation of safety standards falls short is a lack of training and expertise. “Safety implementation still has a long way to go, and one of the main problems is getting those responsible up to speed,” says Ed Bullerdiek, control group leader at Marathon Ashland Petroleum, Findlay, Ohio.
“The scope of control systems and, therefore, training time has increased greatly during my career. We have reached the day where external experts will be used for many aspects of system design and implementation, such as safety. Having internal staff competent in all aspects will be impossible for all but the biggest operations to support and justify,” adds Bullerdiek.
Having said all that, it’s also true that there are gaps in critical safety standards.
Where Standards Come Up Short
Alarm management is the primary area of safety standard shortcomings. “The basic safety theories and standards are sound, but alarm management standards are non-existent, which consistently contributes to process accidents,” says John Bass, senior plant process computer analyst at Minneapolis, Minn.-based Xcel Energy’s Pawnee Station.
Robert Weibel, president of alarm management vendor TiPS, says, “While there are comprehensive standards regarding process safety, the few existing alarm management regulations are buried within documents of a much larger scope. ISA is currently developing a dedicated alarm management standard through the efforts of the SP.18 committee, but alarm management as a discipline is less mature than safety and is evolving.”
Poor or non-existent alarm management standards lead directly to operational problems. “There are too many alarms, and the operator does not know which alarms require action, so they just ignore all of them,” says Douglas Rheinheimer, principal controls manager at Pittsburgh-based Heinz North America. “Alarms should have two levels. The first level should notify the operator that he or she must take corrective action. The second level for the same parameter should take control and shut the process down in a safe mode.”
Modern control systems make it easy to add too many alarms. “Alarms tend to be added constantly, but rarely deleted,” says Gary Woodward, director product marketing and business development, Emerson Process Management. “The mindset of ‘If it costs nothing, why not alarm it?’ becomes an easy trap to fall into. The situation is often further exacerbated by inadequate operator training and poorly designed operator displays.”