ChemicalProcessing.com has a great article on how to more effectively manage plant alarms. The article, Make Some Alarming Moves—Tackle distractions that impair operator performance and process efficiency, by exida consulting‘s Todd Stauffer and Emerson’s Kim VanCamp, highlights the impact operators have on plant operations and ways to help them through more effective alarm performance.
The authors note that operators, through their actions, can have great influence on product quality, raw material usage, and energy usage. These actions in turn impact yield, production rates, and resource utilization. Many plants see this impact through operator shift-to-shift variations. These variations can be reduced by controlling the plant alarms through the elimination of nuisance alarms as well as providing better information on what to do for the remaining alarms.
This is more than a one-time effort; it should be an ongoing program. They describe [hyperlink added]:
…how to create a program to optimize the alarm system by following the alarm management lifecycle defined in the ISA-18.2 standard “Management of Alarm Systems for the Process Industries”.
There are many great alarm analysis tools to help identify nuisance alarms and other bad actors. One of the ISA 18.2 guidelines pertains to the alarm rate. The rate should be on average one alarm every 10 minutes and a maximum manageable rate of two every 10 minutes.
The authors share a simple test that can be done if you don’t currently have one of these alarm analysis software packages:
…you can obtain useful insights just by taking a clipboard into your control room and charting what happens in a typical 20-minute period.
They describe an example of this charting done within a plant that captured 8 alarm horns, 8 operator alarm acknowledgements, 2 times the operator actually took action, and 12 standing alarms (acknowledged but presently in alarm). The operators did not refer to documentation to decide which alarms should be acted upon and which could be ignored. Senior operators often have vast knowledge of how the plant runs that is not documented anywhere for the less experienced operators.
The authors note that poor alarm performance has led to many publicized plant accidents. Regulations and insurance policies are changing to require alarm management programs along the lines of ISA 18.2. They cite [hyperlink added]:
…new regulations like the U.S. Pipeline and Hazardous Materials Safety Administration’s 49 CFR 195.446 (Section e focuses specifically on alarm management) and heightened insurance industry scrutiny provide compelling motivation to create a sustainable alarm system performance improvement program.
Implementing an effective alarm management program improves operator performance by eliminating nuisance alarms, improving the design of alarms, and providing better operator access to alarm and process knowledge—the “what to do”. In the alarm design review portion of an effective program, the alarms should be based on:
…firm process knowledge such as root cause, process dynamics, operational limits, consequence of inaction, time needed/available to respond and an understanding of the steps the operator must take to respond.
ISA 18.2 provides a forward path to implement a program through an alarm management lifecycle process. The authors cite an article, Avoid the Domino Effect, which provides a good overview of the standard and lifecycle process. Improvement and better operator performance can occur through these 7 steps:
- Create an alarm philosophy document.
- Measure alarm system performance, compare to key performance indicators (KPIs), and identify problem alarms.
- Review the existing alarm system design and rationalize the alarms.
- Document results in an alarm response procedure and train operators on how to respond.
- Run revisions through the management-of-change process.
- Implement alarm system changes dictated by rationalization.
- Repeat periodically, starting at Step 2.
Each of these steps is described in more detail in the article. Give it a read if you don’t currently have an effective alarm management program in place and want to get on the path to improvement.