What will Alarm Management do for me?
Without effective alarm management, you cannot be certain that your operators will respond effectively when there is an upset. Alarms should define the boundary between normal operation and abnormal operation.
The following figure shows this relationship:
Continuous monitoring detects disturbances that the operator must respond to in order to assist the automatic control system regulate the plant
DCS alarms alert the operator to significant upsets that must be corrected
Safety system alarms indicate the onset of critical events that require fast, sometimes radical, action, such as shutting down the plant.
A properly applied Alarm Management program ensures that the alarms are:
Configured properly and enforced, so they are set at the right operating conditions
Understood by the operator, and so are effective
Practical, so the operator has enough time to respond to the alarms before a significant loss occurs
How do I do it?
There are essentially two routes to improved Alarm Management:
Continuous improvement of normal operations
A new Alarm Management program
Both approaches start with an assessment.
The Alarm Management Assessment (AMA) is an evaluation of your current operation by trained, experienced personnel, who examine all aspects of your existing alarm management systems. The AMA evaluates your current exposure to risk as a result of poor alarm management, and provides you with a grade in each of the different areas of Alarm Management, as well as an overall grade for your plant. Depending on the grade, the AMA recommends one of two different courses in each area.
The areas of Alarm Management evaluation are:
Alarm Definition: the existing procedures for defining and configuring alarms, alarm settings and priorities; the documentation of alarms and alarm-related procedures.
Management of Change: the effectiveness of the plant organization in maintaining the alarm settings once defined, and in ensuring that alarm settings are updated when physical equipment, procedures and plant operating parameters change.
Operator Readiness: the current state of operator training in response to alarms, and the systems in place to ensure operators are trained, qualified, and able to respond to alarms.
Alarm System Effectiveness: the actual performance of the alarm system during normal operation and upsets; the frequency of nuisance alarms and alarm floods; the availability of the alarm documentation as and when needed; and the effectiveness of the alarm system during significant operating incidents.
If the existing practice in an area receives a grade of B or A, then there is no urgent need for improvement in that area. You may need some management systems to ensure that performance is maintained or improves continuously over time; however, large amounts of effort are unnecessary in that area.
If the existing practice receives a grade of C or lower, then there is an organizational need to improve in that area, as described in the following sections.
Approaches to Alarm Improvement
There are two alternative approaches to alarm improvement. The appropriate approach depends on the grade from the Alarm Management Assessment. If the existing Definition, Management of Change and Operator Readiness processes are effective, then the alarm system can be improved by relatively simple continuous monitoring and continuous improvement. If the support processes are not in place, a more thorough approach is necessary.
If all is well, or if there are other organizational priorities, then you can apply a continuous improvement philosophy. You can greatly reduce nuisance alarms during normal operation by this method, however, this approach is effective at improving and maintaining only an already well-managed alarm system.
Collect data. Collect alarm history for at least a month, including all alarms for all consoles along with all operator actions. This data will provide both an original benchmark and the basis for alarm analysis.
Analyze. Typically, most nuisance alarm occurrences result from a surprisingly small number of actual configured alarms. The initial alarm analysis will quickly identify those alarms most in need of reconfiguring. It will also provide insight into the severity of the current problem.
Benchmark. Analyze the alarm history to determine whether the current rate of occurrence is within the EEMUA guidelines for standing alarms, alarm occurrences per shift, and for alarm bursts. Analyze alarms area-by-area, since some operating units or areas are more prone to alarms than others. Using the alarm history, measure the original performance as a benchmark for comparison to show improvement in nuisance alarms over time.
Spend 1 or 2 days per month doing Alarm Management. As more alarm history is collected, a senior operator and an engineer should spend a day or two a month to find the worst nuisance alarms and reconfigure them in the DCS. Over the long term this can have a significant effect.
Measure to confirm that improvements are being maintained. The monthly alarm occurrence statistics will show the frequency of alarms and the number of standing alarms decreasing over time. This can be very powerful evidence of an effective alarm management program.
An Alarm Management Program for the 21st Century
This approach is similar to the Six Sigma program: first the problem and objective are defined, then the current state is measured and analyzed, action is taken to improve the situation, and finally the situation is monitored automatically to control, or sustain improvement.