A Case Study on Increasing Alarm Quality to Improve Operator Situational Awareness and Effectiveness

A District Energy Solutions Provider of Steam and Power

The customer utilizes 15 DeltaV Operator Stations throughout the plant, and the Alarm Summary Overview Screen was cluttered with nuisance alarms that were outdated and irrelevant, which overwhelmed the operators and made it difficult to focus on the process.

These nuisance alarms were often coming from equipment that wasn't running or from intermittent instrumentation issues, leading to stale alarms where the rate of alarms and standing alarms exceeded what operators could effectively manage. 

These alarms fell into several categories, including:

• Stale Alarms: Alarms that remained in an active state for an extended period without requiring action, cluttering the alarm summaries.
• Chattering Alarms: These alarms repeatedly transitioned between active and inactive states in a short period, causing significant distraction.
• Fleeting Alarms: These alarms activated and cleared within a second or two without repeating immediately, often sounding the horn without indicating a real problem.
• Incorrect Alarm Priority: There was an excessive number of high-priority alarms compared to medium and low priority alarms, making it difficult for operators to distinguish the truly important alarms.

Additionally, overall alarm performance metrics were outside the target range for:

• Average Alarms per Day
• Average Alarms per 10-minute period
• Peak Alarms per 10 Minutes
• Average Number of Standing Alarms
• Distribution % of Alarm Priorities

These challenges stemmed from an inconsistent implementation of the alarm management system over the years due to the lack of effective alarm philosophy documentation.  This was particularly problematic during unplanned events, where the number of alarms in a 10-minute period reached as high as 340.

Addressing these nuisance alarms was crucial to improving the overall efficiency and safety of the plant operations, but the recent departure of a key engineer made it more difficult to devote internal resources to this alarm management project.

With limited internal resources and the need to improve operator situational awareness, the customer chose to leverage services from their Site Support Plan with Novaspect for expert assistance.  Novaspect’s Systems Solutions engineer utilized DeltaV AgileOps™ Performance Analytics to generate reports, which compared the alarm data over 30-day periods to the ISA 18.2 standard best practice and identified the top alarm bad actors.  The reports and alarm bad actor list were reviewed with the client’s team to determine next steps.

Specifically, the process for this site included:

• Conducting Detailed Alarm Analysis:  Generating & reviewing alarm reports to gain a comprehensive understanding of the current state of the alarm system.
• Identifying and Targeting Bad Actor Alarms:  Focusing on the most frequent and nuisance alarms to identify poor quality alarms that should be addressed.
• Developing a Consistent Approach:  Working with the customer’s management team to establish a clearly documented and effective approach to alarm point modifications.   
• Cleaning Up the Database: Ensuring the current equipment matches the control system database and removing control strategies that were no longer used along with their associated irrelevant alarms.
• Implementing Dynamic Alarming:  Leveraging Conditional alarming to minimize the total number of active nuisance alarms by evaluating process conditions before triggering alarms.   
• Addressing Chattering Alarms:  Adjusting alarm deadbands and addressing intermittent instrumentation and communication issues to resolve alarms that were repeatedly transitioning between active and inactive states.

• Alarm Philosophy Document: Serving as the implementation guide and ongoing reference tool, this document will establish the criteria, definitions, responsibilities, and principles for the alarm management lifecycle stages, ensuring consistency throughout the plant.
• Alarm Rationalization:  Reviewing and optimizing alarm setpoints, conditions, and design to ensure they are appropriate and necessary for safe operation.
• Alarm Prioritization:  Correctly categorizing alarms based on their severity and importance to help operators focus on the most urgent issues first.
• Alarm Filtering and Suppression:  Filtering out unnecessary alarms and temporarily suppressing alarms under specific conditions to improve operator situational awareness and reduce alarm floods. 
• Event Logging and Reporting: Capturing alarms, events, and operator actions to create a detailed history for performance analysis, troubleshooting, and regulatory compliance.

Novaspect’s engineer continues to visit the customer’s site monthly to work with the team and perform Bad Actor cleanup services.  This ongoing support will continue to help operations and ensure that the alarm system remains optimized and effective.

The results were immediate and impactful.  Standing alarms and alarm floods were significantly reduced, and the operators no longer had to scroll through irrelevant alarms.  The Alarm Summary List became a valuable tool for identifying critical issues, improving the overall efficiency and safety of the plant.  The customer quickly saw the benefits, with a cleaner alarm screen that facilitated better situational awareness for more focused operations, minimizing the training requirements for new operators.
 
Key outcomes included:

• Significant Reduction in Nuisance Alarms: The number of nuisance alarms was drastically reduced, allowing operators to focus on critical alarms and managing the process.
• Improved Operator Efficiency and Focus: With fewer distractions, operators could respond more effectively to all alarms, enhancing overall plant performance.
• Enhanced Plant Safety and Training: A cleaner alarm screen made it easier to train new operators and maintain high safety standards.

The customer now has a more robust alarm management system in place, ensuring that alarms are displayed and addressed in a timely manner, leading to a more efficient and safer operation.