“You must learn from the mistakes of others. You can't possibly live long enough to make them all yourself,” to quote Sam Levenson. When it comes to alarm management, Levenson is correct.
Ineffective alarm systems pose a serious risk to safety, the environment, and plant profitability. Too often, alarm system effectiveness is unknowingly undermined by poorly-configured alarms. Static alarm settings can’t adapt to dynamic plant conditions. A flood of nuisance alarms overwhelm operators just when they most need concise direction (Figure 1). Operators and engineers in the chemical industry have become increasingly aware of the value of alarm management systems. If set up properly, they can identify abnormal situations, allowing operators to move the process back to a safe condition.
Figure 1. Typical stressful day in a control room
As alarm management solutions become more common, our understanding of the factors that impart success has grown. If you’re thinking of undertaking an alarm management solution, or if you have already started one, the following information based on lessons learned, can help drive your project to success.
Establishing a reliable system
The process for founding a successful alarm management system is fundamentally the same across industries, regardless of plant size. As with continuous improvement it is an ongoing, dynamic process:
- Benchmark and evaluate current performance: This is the time to identify problems with your alarm system. Some results can be surprising. Figure 2 clearly shows a high frequency of emergency alarms that should be investigated. The Engineering Equipment & Materials Users’ Association (EEMUA) suggests that by dividing your alarms into three categories: emergency, high, and low, the optimum proportions should be a ratio of 5:15:80.
- Develop an alarm philosophy document: This critical document clearly outlines key concepts and governing rules for your alarm strategy. It should answer such questions as: What constitutes a critical alarm? Which alarms should cause trips? Which alarms should be allowed to be inhibited — under what conditions and who should have authority? Which alarms are advisory? The philosophy also outlines roles and responsibilities, change-management procedures, and the project goals, such as target alarm rates. There is good news for those who find it difficult to compile the philosophy document. Templates are available that do most of the work for you — all you are required to do is include your specific metrics and situation.
- Rationalize alarms: First, target and eliminate the top 20 to 30 bad actors to significantly improve alarm loading. Find out which alarms occur most often. Determine which alarms are significant (Figure 3). A complete review of the process operation related to when alarms are active is necessary. After this is completed, a review should be held with operations to ensure that alarm priorities convey consistent urgency to the operator. In its final form, a configuration review document should be prepared — ready for the next step.
- Implement changes: Control system re-configuration makes the intentions of alarm rationalization a reality by eliminating nuisance alarms at their source. Part of this step includes integrating maintenance of the alarm manager into the plant workflow. Integration includes updating operating procedures and record-keeping. Maintenance must involve a documentation procedure that feeds continuous improvement.
- Strive for continuous improvement: Hold routine review sessions to identify new opportunities for enhancements, such as dynamic alarm strategies.
Figure 3. Alarm-rationalization includes frequency plot of tag names
Now that we have defined the correct execution path (Figure 4), let’s take a look at the recent lessons learned by industry:
Figure 4. The step-by-step process for rationalizing alarms
Blunder 1: poor project management. Poor planning, sketchy system design, inadequate resource allocation, incomplete scheduling, and ineffective management of operator expectations can destroy the success of any project; alarm management is no exception. The single most important activity is planning — detailed, systematic, team-involved plans are the foundation for project success.
Blunder 2: using the wrong tools. Delivering the optimum return depends on selecting the right platform for achieving alarms and events. Selecting the proper alarm analysis tool is also critical.
The archive system and analysis tool will assure that you are chasing down major problems not being bogged down in nuisance alarms.
Beyond simple analysis, tools that enable automatic change control, punch-list generation, and project tracking are available. Give forethought to how leveraging alarm information will be achieved once this knowledge is in a repository. Although these tasks can be performed without special software tools, it isn’t practical to do so. The effort often becomes so daunting that alarm management initiatives can collapse under the weight of their own logistics. It is best to do away with paper trails in the form of spreadsheets and change control documents posing as Master Alarm Databases. Use the right tools.