Avoid Alarm Blunders

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. Read about these 12 common mistakes that can undermine the management of your alarm system.

By Michael Marvan

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Blunder 7: failure to automate. Good technology makes life easier.  Its purpose is to relieve people of dangerous, repetitive tasks, freeing them to intervene when the automated system requires guidance. When intervention is needed, software should make problem assessment and diagnosis easy — freeing the user to fix the problem.

Although task accountability is necessary for successful alarm management, staff is more likely to use reliable technologies that are available on demand to make their jobs easier.

Blunder 8: are your operators acting on alarms? People often mistakenly fail to track all of the data required. Tracking alarms isn’t enough! Alarm rationalization mandates more than one type of data.

For example, when an alarm occurs you need to know if an operator actually responded to it.

Tracking operator actions is an effective way to identify control problems, automation opportunities, and audit the effectiveness of your alarm strategy. If the operator didn’t respond, there is a good chance that the alarm is a nuisance alarm. Examine the ratio of operator actions to audible process alarms in order to identify poor alarm strategies. The de facto standard “every alarm requires operator intervention” demands this ratio exceed one.

Other data to track consist of operator actions, including controller set-point, mode changes, and system errors. If a controller’s mode, or output, is repeatedly changed it is a clear sign the loop needs fixing. The loop is over-dampened or under-dampened. If action data are coupled with controller performance data, an understanding of the loop’s problems can be quickly diagnosed, saving time. If a controller’s set-point is frequently changed and the controller has no supervisory control, then the automation engineer must ask “why not?”  Installing new automation strategies can free the operator to focus on pushing limits rather than maintaining process stability. In addition, process variable history is important for determining some deadband alarm settings, or for performing the engineering reviews prior to implementation.

Blunder 9: treating all data the same. Audible alarms are not the same as non-audible alarms. Many control systems continue to send alarms to the journals when alarms are not audible. Failure to separate these data creates an inaccurate picture of alarm system performance and may lead personnel to think the situation is worse than it is. Moreover, this may waste time by falsely indicating alarm problems.

Blunder 10: who reads user manuals? I confess to not reading my motherboard manual the last time I bought a computer. Nor did I read the instructions for my television, DVD player, microwave, and certainly not the 1,800 page operating-system help files. I know you’re guilty, too. The easiest way to undermine effective alarm management is to implement a solution without giving personnel the hands-on training they need. This point is perhaps best illustrated with a real-world example:

A large petrochemical plant went to great efforts to improve its alarm system performance through alarm rationalization. Once the new settings were designed, changes were uploaded to the control system over the span of two months. Training was provided throughout this period. Joe, a veteran operator with 21 years of experience, was entitled to five weeks of vacation per year. Shift rotations at the company normally consisted of four weeks on and one week off. Joe had recently earned some time-in-lieu by working some shifts for a co-worker.

With these factors combined, Joe decided to take two months off. Guess when? On Joe’s first day back, there was a compressor trip.  This caused a single emergency priority alarm to be sent to the control system. Joe was accustomed to assessing the plant’s state based on the rate of alarms. He naturally assumed things were running quite smoothly: he had only a single alarm in nearly 30 minutes! His delayed intervention escalated the upset to an unnecessary plant shutdown. Effective operator training ensures that operators know what needs to be done, when, and how. Remember team-involved plans are the only foundation for project success. If a plant is unable to provide effective in-house operator training, call upon companies that specialize in third party training.

Blunder 11: overhauling the whole system at once. Implementation should be staged. If all changes happen at once, plans become complicated and it never gets done.  Recognizing this prior to rationalization will help personnel break the execution into easy steps. This enables operations to become accustomed to the changes gradually, thus improving the chances of success.

Blunder 12: no accountability. Failing to assign roles and responsibility is the most common — and most deadly oversight in an alarm management project. I advocate resolving this by encouraging “accountability through visibility.” In other words, make sure all staff have access to their peers’ data. This will motivate your plant personnel to work together and prove they run the “tightest ship.” Some sites may make excuses and complain, but in the end they will improve plant operations to avoid repeated corporate humiliation. This sounds harsh, but it works.

It’s best to define maintenance tasks and assign responsibility early in the project, such as during the project plan design. This must be done in a simple manner, both textually and in actual day-to-day practice, to ensure the sustained support of the idea.  This will give personnel an opportunity to participate during installation and validation of the system; they will “own” the new system.

The final word

Alarm management solutions can significantly improve plant safety, reliability, and profitability, but will only succeed if they are implemented properly. If you follow the recommended project methodology and avoid the mistakes we described, you should be successful. An efficient alarm management system will make your personnel more productive and improve the reliability of your plant.

For additional alarm management resources, view Matrikon’s online and interactive multimedia presentation at http://www.matrikon.com/am_tutorial/.

Michael Marvan, is a product manager for alarm management solutions with Matrikon in Edmonton, AB, Canada; email him at Mik.Marvan@matrikon.com.

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