In today’s manufacturing environment, where fewer experienced people are running the plant, well-designed alarm strategies are more important than ever. A timely, clear, accurate alarm—one that is not buried in an alarm flood—can mean the difference between safe operation through a process aberration or a disaster that impacts safety or creates an environmental incident.
Plant operators know the importance of good alarm management, and so they’ve been striving for years to meet ISA 18.2 standards for good engineering practices for alarm management. But alarm management is a science of its own. In a recent article in Chemical Processing, Emerson’s Darwin Logerot shares nine misconceptions that often lead engineers astray when designing alarm strategies.
The right visibility is key
Engineers know operators need to see their alarms clearly. If a crucial alarm is buried in a flood of nuisance alarms, the odds are an operator will not be able to react in time. However, visibility is not necessarily about the number of alarms, but rather the effectiveness of those that are presented. Darwin explains,
“Thinking in terms of quantity rather than quality is a mistake. The goal of effective alarm management is to identify quality alarms and keep them in service while improving or eliminating nuisance alarms.”
He defines five keywords and definitions critical to creating quality alarms. In fact, according to Darwin, the quality of an alarm is negative if it does not conform to the following keywords and definitions:
- abnormal — not planned or expected, a surprise to the operator
- actionable — operator response to the alarm is required and possible
- consequential— lack of or incorrect/insufficient action likely will lead to an undesirable result
- unique — only one alarm sounds to announce an abnormal deviation
- relevant — understandable to the operator and pertinent to the current operating state
Don’t create your own floods
One of the key definitions in the above list is “unique.” While it may seem like alarming everything in the plant or creating multiple alarms for crisis situations might draw more attention to problems,
“as alarms flood in, operators quickly can become confused as to which they must address first, delaying responses. Moreover, even when operators identify the source of the problem and begin to take action, they waste valuable time silencing the other alarms.”
A better strategy, Darwin suggests, is to create and trust a single, high-quality alarm for each event. A single alarm presenting important details and clear severity information will help operators understand and prioritize issues in the plant.
Dynamic alarming is key
Plant operations are not static, so it makes sense that alarms should not be static either. As the plant conditions and activities change from day to day, alarm management needs to be able to change with them. When the current operating environment does not reflect the design of alarm conditions, nuisance alarms are born.
“Alarms, by definition, identify abnormalities in plant and equipment operation. However, what is normal and abnormal often varies with operating state. As a result, to be effective, alarm management also must adapt to the state of the plant.”
Dynamic alarm management, a feature available in advanced alarm management technologies like Emerson’s AgileOps software, can help keep the alarm system optimally configured across changing process states. And when that dynamic alarm management is integrated seamlessly with the distributed control system, dynamic alarm management becomes even easier.
Know your audience
It is important that a good alarm strategy is based on metrics and is designed to satisfy management, but it is also important not to forget the key audience for alarms: the operators. Experienced operators can offer strong guidance to designing alarms that will help them more safely perform their jobs. Darwin explains,
“Developing an alarm strategy that satisfies ISA 18.2 guidelines means designing based on solid principles and on the feedback of the board operators who must deal with each alarm. Therefore, an alarm configuration that empowers operators to control the process effectively and safely should be one of the ultimate goals of the program.”
Use the tools at your disposal
Designing a sound alarm strategy doesn’t require engineers to solve every problem for themselves from the ground up. Powerful alarm management toolsets like those available in Emerson’s AgileOps come with helpful alarm management tools such as native integration with the DeltaV™ distributed control system, dynamic alarm management, and intuitive dashboards. Implementing these toolsets from the earliest stages of alarm design helps teams configure alarms correctly from the very first moments of operation and drives improved value across the lifecycle of plant equipment.
For more advice and specific examples on avoiding alarm management pitfalls, you can read Darwin’s article in its entirety at Chemical Processing magazine. And while you’re here, I’d love to hear your unique strategies—alarm-based or otherwise—that have helped keep your operators safe and alert. Feel free to comment below.
Update from Jim: Join us at the October 24-88 Emerson Exchange conference in the Dallas-Fort Worth Texas area to hear Darwin and his co-presenters share alarm management lessons and best practices from a large-scale, grassroots ethylene cracker & polyethylene complex project.