How to succeed at alarm management

Find out how you can improve the effectiveness of your distributed control alarm systems by better managing the techniques, tools, standards, and procedures you use in your process plant.

By D. Shook PhD, PE,

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The objective of this approach is to produce a self-sustaining alarm management competency within the organization, and to bring the initial benefits of alarm management as quickly and effectively as possible.

  1. Create an alarm philosophy. Define the purpose of each type of alarm or message that is issued by an automated system. Specify the criteria for each priority, for hardware alarms and for when an alarm is needed at all. Best practices in this area include Integrated Risk measures, addressing human factors, and cognitive limitations of human operators. Define other alarm management policies, such as the business rules governing alarm changes, the inhibiting or suppressing of alarms, expectations of operators, and so on. This step produces a document that clearly defines the objectives of the alarm system and the ground rules for its implementation.
  2. Benchmark alarm performance. Assess the actual current state. This provides useful data for the following analyses, and also provides a benchmark of the original state of the organization. Alarm configurations and history are collected from the DCS and analyzed with ProcessGuard.
  3. Decide which areas require rationalization. Alarm Rationalization, or Alarm Objectives Analysis, is a procedure where each alarm is examined to ensure it conforms to the alarm philosophy. During this process, many alarms are eliminated, others have their priorities changed, and still others have their trip points altered. The process can be time-consuming, and so it is best to start in those parts of the plant that have the worst problems with alarms.
  4. Implement Alarm Configuration System. After choosing a starting point, implement a database to collect, retain, control, and present the information collected during the Alarm Objectives Analysis process. This database will form both the change management system and the online operator assistance.
  5. Commit Resources. This team will need to work together for several weeks, so free them of most of their other responsibilities for the duration of the analysis. Form a team consisting of:
    - A facilitator, familiar with the AOA process and with alarm analysis
    - At least one area operator, preferably two
    - The area process engineer
    - The area production supervisor
    - An area instrumentation technician
  6. Conduct AOA Meetings. Use analysis reports as evidence of problems or situations.
    Review the configured alarms and answer several questions regarding actual alarm
    occurrence and the purpose for the alarm. For example:
    -  Possible causes for the alarm, whether legitimate (providing information), spurious (misleading or nuisance) or redundant (telling the operator something he already knows)
    - The procedure to identify the cause and thus validate the alarm
    - The procedure to mitigate the different causes
    - The time frame the operator has to respond in, before some undesirable consequence occurs
    - The follow-up action required to verify that the procedure was effective
    - The historical frequency at which the alarm occurred, and how many occurrences were spurious or redundant
    - The final alarm trip point and priority
  7. During the AOA process, consider alarms that do not exist, but should in addition to considering existing alarms.
  8. Re-configure DCS. Implement the changes from an AOA carefully, not made piecemeal. An AOA results in an alarm system that is designed to alert, inform, and guide the operator. The set of alarm configurations work together to define the boundaries of normal operation--if AOA configurations are made piecemeal, some alarms may be removed before alarms intended to replace them have been configured. In that case, the plant will be less safe. It is also important to introduce continuous monitoring applications identified during the AOA. Continuous monitoring applications, such as multivariate trends, provide the operator with improved visibility into the process, without having to rely on alarms as the operator’s "eyes and ears." Much of the barrage of alarms during upsets is a result of the misuse of alarms to alert the operator that an expected event has occurred. Continuous monitoring restores the alarms to their original function of identifying unexpected events that require a response.
  9. Human factors. Ensure the human factors are addressed, such as the design of the operator interface in the DCS to the number of independent systems that emit alarms, the audible alarm itself and when (and whether) it can be silenced.
  10. Continue to measure and sustain alarm system effectiveness. ProcessGuard can monitor the actual alarm occurrences, fine-tune the alarm settings, and identify errors made in the AOA. The plant personnel who participated in the original AOA will be able to maintain it as changes are made to the plant.

Conclusions

  • Alarm management is just good process plant management.
  • Advances in technology and increases in government regulation have jointly made alarm management more important and more difficult.
  • Poor alarm systems contribute to production losses, equipment damage and injuries during critical incidents.
  • Many plants can improve their alarm management without major costs.
  • Matrikon can provide Alarm Management Assessments, Continuous Improvement Programs and full Alarm Management Programs.

Appendix:

Management Responsibilities
OSHA APPENDIX C TO 1910.119 - COMPLIANCE GUIDELINES AND RECOMMENDATIONS FOR PROCESS SAFETY MANAGEMENT

In addition, various engineering societies issue technical reports that affect process design.

For example, the American Institute of Chemical Engineers has published technical reports on topics such as two-phase flow for venting devices. This type of technically recognized report would constitute good engineering practice. Operating procedures addressing operating parameters will contain operating instructions about pressure limits, temperature ranges, flow rates, what to do when an upset condition occurs, what alarms and instruments are pertinent if an upset condition occurs, and other subjects.

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