Alarm Rationalization

As plant operations become more complex, proper alarm annunciation becomes even more critical to plant operations. The Yokogawa Alarm Rationalization services provide the necessary engineering and/or consulting to sustain the defined alarm system performance throughout the lifecycle of the facility.

Customer Challenge

Avoiding Risks Caused by Inefficient Alarming

In recent years, plants have experienced increased alarm flooding. This leads to the oversight of important alarms while at the same time significantly adding to the scope of operator tasks. It is becoming increasingly difficult to realize safer, more stable, and efficient plant operation with limited human resources. Therefore, the necessity of alarm validation, optimization and management is becoming widely recognized as an important countermeasure. Implementing alarm management is not an easy task, because managing and coordinating the ongoing improvement effort requires the coordination of resources across several departments such as Maintenance, Engineering, Operations and Process Control.

Our Solutions

Our Experience Guides the Alarm Writing Process

Yokogawa's Alarm Rationalization Services are solutions meant to sustain your alarm system performance throughout plant lifecycle. Our services are provided in three phases:

  • Fundamental Nuisance Alarm Reduction is the preparatory service to identify the root causes of existing nuisance alarms and take proper countermeasures to reduce them
  • IEC-62682/ISA18.2/EEMUA #191-based Alarm System Design is the main service to establish the consistent philosophy for alarm system design based on EEMUA guidelines and ISA18.2/IEC-62682 standards, and incorporates it within CAMS (Consolidated Alarm Management System)
  • Operational State-Based Alarm Management is the additional service to manage alarm thresholds and alarm suppression based on the different operational states

Clients are allowed to proceed immediately to the phase that corresponds to the current status of their alarm rationalization activities.

Customer Benefits

Optimized Alarms Lead to High-Level Safety

Typical benefits are:

  • Optimized alarm messages sent to the right people, at the right time
  • Operators spend less time on alarms and more time on true process concerns
  • Decrease in potential risks such as:
    1. Serious plant damage
    2. Lost production
    3. Environmental incidents
    4. Endangering life


Yokogawa's alarm rationalization service is based on standardized Six Sigma DMAIC methodology. This provides clear and effective steps to achieve a defined target while ensuring consistent and high levels of service quality.

  Phase 1
Fundamental nuisance alarm reduction
Phase 2
EEMUA #191-based alarm system design
Phase 3
Operational state-based alarm management
1. Define Establish cross-section task force
Set target alarm system performance in steady-state operation
Establish cross-section task force
Set target for alarm system performance during plant upset
Hold on-site CAMS for HIS training for team members
Establish cross-section task force
Set target for alarm system performance in steady-state operation
Hold on-site AAASuite training for team members
2. Measure Acquire A&E logs for multiple operational states Acquire necessary information regarding current design policy
Acquire A&E logs for past plant upset (where possible)
Acquire A&E logs and historical trends for multiple operational states
3. Analyze Sort acquired A&E logs
Identify root causes of nuisance alarms through team discussion
Decide proper countermeasures to reduce them
Analyze acquired information to identify improvements
Establish new design policy based on EEMUA #191 guideline
Analyze acquired data to decide target operational states and tags
Analyze acquired data to decide proper alarm threshold or AON/AOF condition
Consider application of DCS sequence program for automatic switchover
4. Improve Take practical countermeasures within two months Incorporate new design policy in CAMS for HIS within two months Incorporate new policy in AAASuite package
Incorporate DCS sequence logic for automatic switchover
Debug implemented application with FCS test function
5. Control Evaluate improvement effect
Confirm remaining actions
Report on results of service
Evaluate improvement effect
Report on new design policy
Evaluate improvement effect
Report on new design policy

*1: This is a consulting service for CAMS for HIS (Phase 2)/AAASuite (Phase 3) installation.
*2: This service is provided by executing the above five steps of the DMAIC cycle.


Alarm management is not just a project that has a start and end date; it's a continuous cycle. Once the alarm system has been reviewed and improvements have been identified, we must check that controls are in place to ensure the alarm system remains functional. The key is to ensure that the system is continuously monitored and any changes are fully documented. There are seven key steps for alarm management. Rationalization is one of those critical steps.


As plant operation becomes more intelligent and complex, the alarm system for safe and stable operation is becoming increasingly important. An alarm warns operators of an abnormal situation in a process and urges them to respond to it.


In recent years, safety and profitability have become ever more important in the process industry due to fierce global competition. Greater emphasis is being placed on highly efficient plant operation for reducing the increasing energy bill.



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