Document and Bring in Veterans
"We had about 6000 analog I/O points, and this meant dealing with about 10,000 decisions just to rationalize alarms and alerts from our analog signals," explains Dobel. "We wanted to give our operators an alarm system that would provide timely, accurate information to assist in operating the powerhouse in a controlled manner; employ Matrikon's Alarm Manager management of change (MOC) software to handle the rationalization; set up and execute an alarm rationalization scheme following EEMUA 191's principles; and provide rationalization data to the operators' consoles."
Dage adds, "Previously, we were putting Band-Aids on the bleeders in our alarm system, but we weren't completing the documentation needed. This was the first time we did full documentation."
Dobel added that GWEC also hired a senior software engineer from Matrikon to help get its three-month, $250,000 alarm rationalization project started; hired some retired operators to help; and set up a dedicated Alarm Rationalization Room to present component data, trace alarm profiles and facilitate hashing out the most logical and efficient ways to reorganize and reassign them.
"If you haven't done a rationalization project before, we recommend you hire an external expert to help, but make sure you check their credentials and bring them in for a trial week to see if they can do what you need to get done," adds Dobel. "Also, using retired operators was helpful because they walked down the system and traced many devices and alarms, but it was also a mistake because we needed to get more of our current operators involved too. A good rationalization team should have a panel board operator, a DCS expert that knows all the logic blocks in the systems and how they relate to the alarms, instrument technicians, and a scribe to keep everyone on track.
"The rationalization room got everyone on the same page. A lot of tribal knowledge had built up in our processes, and we needed to eliminate it by standardizing on common best practices. So, it helped to talk about what was bringing us to certain alarm situations."
The rationalization team started with GWEC's I/O tag list and the plant's piping and instrumentation diagrams (P&IDs). "We found we could sort the tag database however we wanted, but we learned it was better to take the P&IDs and rationalize the whole system," says Dobel. "You have to ask questions like, 'What flow do I need here?' or 'What level do I need here?' The aim is to avoid unnecessary double alarms, but it can take a long time do them--sometimes three or four hours to reach consensus on one alarm. You have to get your subject matter experts (SMEs) for the process on speed dial."
Help Operators Do Their Jobs
GWEC also used AlarmInsight software to present alarm profiles and operating data to its operators in a more concise and less text-heavy format. "Besides delivering important alarms, we tried to give our operators assistance beyond the routine and obvious tasks, and help them with things they might not think about at 3 a.m. So we focused more rationalizing some of these unusual events." says Dage. "For instance, we found we rarely used Level 2 and Level 3 alarms, so we began to discuss the reasons why, and document our alarm philosophy."
Likewise, to optimize its own alarm system, Compañía Mega recently held joint workshops with Honeywell Process Solutions, and implemented its Alarm Configuration Manager (ACM) software. ACM was integrated with the plant's existing process control system, Honeywell's TotalPlant Solution (TPS), and implemented recommendations from EEMUA 191. Mega is a joint venture between the Dow Chemical Co. and Brasoil Alliance Co., which provides hydrocarbon feedstocks to Dow's Bahia Blanca site in Argentina and has two gas plants linked by a 600-km pipeline.
In short, Compañía Mega and Honeywell used ACM and EEMUA's guidelines to:
- Standardize the alarm process by defining a plant alarm policy, so all staff operates with the same quality of alarms.
- Dramatically reduce the number of alarm activations requiring operator intervention.
- Provide peace of mind to operators by not overwhelming them with unnecessary alarms.
- Improve the response time of operators to verify incoming alarms and make decisions when an alarm is activated.
- Reduce human error in the management of alarms, avoiding unnecessary production stops, equipment failure, vents, etc.
This concern about alarm rationalization is gathering steam. Jason Wright, market manager for PlantPAx software at Rockwell Automation says, "We're seeing a mind shift, especially in the process industries, about alarms and HMIs. Historically, alarms were driven just by knowing the process and following the critical elements. HMIs layouts followed PIDs. Today, HMIs are driven by a greater appreciation for human-factors engineering and the best ways to convey information to the operators, so they can respond appropriately.
"Using ISA 18.2 as a guide, we've expanded the Alarm State Model in our PlantPAx 3.0 software to include three distinct alarm suppression states," adds Wright. "The previous two were 'suppression by design' and 'disabled or out of service,' and now we've added a third for granularity called 'shelving,' which allows alarm suppression with an automatic timeout."
Seeing More Clearly
HMIs also can give operators a better understanding and chance to respond to alarms and performance changes.
For example, system integrator One-Step Automation in Niverville, Manitoba, builds automation systems for grain handling and processing, but these users want HMIs they can use anywhere to get real-time feedback on bin levels, motor failures and alarms, surge hopper levels, and the ability to control shutdown processes.