On practically every SCADA/HMI system I have encountered over the years, I have seen operators acknowledging "nuisance" alarms. These are alarms that pop up on the screen, require the operator to click on the screen to acknowledge or silence the alarm, but no other action is required, and there is no adverse effect on the process. So why is it an alarm?
Nuisance alarms can be very detrimental to safety. Human beings are creatures of habit. After clicking the Acknowledge button to silence non-critical alarms multiple times per shift, the operators may gradually begin paying less attention to all alarms, even the critical ones. This can have severe consequences, from loss of product to loss of life.
One strategy to make your alarm notifications more efficient is to separate them into areas of concern. For instance, only display alarms on the SCADA/HMI that require operator actions. These would be critical events that directly impact production or safety. Less critical notifications could be displayed on a production supervisor's screen, in a common area, or in a maintenance shop. Less critical notifications could also be emailed or texted to assigned personnel.
Regardless of how alarm notifications are being conveyed, they should all be recorded by a historian. Reports showing the number of occurrences of each alarm should be reviewed periodically to identify issues with equipment and processes that are causing downtime. This information is an essential tool in identifying "nuisance" alarms and for maintaining a healthy Alarm Notification System.
An Alarm Management Standard, such as ANSI/ISA 18.2, provides a mechanism for identifying and implementing an effective alarm notification system. Even if your facility does not require or currently use a formal standard, it can benefit from some of the core concepts of such a standard.
Alarm Philosophy
Document the objectives of your Alarm Management system. Get input from all affected stakeholders, including Health & Safety, Production, Engineering, Maintenance, and Management. Identify the types of alarms (critical, warnings, informational, etc.), the affected personnel for each type of alarm, and the means of notifying affected personnel.
Identification
Determine any circumstance(s) that may pose a threat to health or safety, indicate loss of product or a downtime event.
Rationalization
For each alarm identified, ensure that it meets the requirements established by the Alarm Philosophy.
Design
Determine how each alarm identified will be presented to production and maintenance personnel. Provide a means to temporarily take the alarm out of service for testing or repair activities.
Implementation
Bring the alarm design into operation. This phase includes commissioning, testing, and training.
Operation
The alarm is now active. Ensure all affected personnel is trained on the meaning of the alarm and the appropriate action(s) to take during and after receiving the alarm.
Auditing
Periodically review each alarm to ensure it is still relevant, that it functions as designed and that it adheres to the Alarm Philosophy. Period reviews of the Alarm Philosophy should also be conducted to incorporate changes to procedures, processes, and regulations.
Management of Change
Have a defined process for making changes to alarms. This should be a written document that includes the reason for the change, determining affected components and processes, and describing the change to be made. It should be reviewed and approved by all affected stakeholders prior to implementing the change. It should also include documenting of testing.
If done correctly, an Alarm Notification System can be a valuable tool for keeping your facility running safely and efficiently. Stark Engineering can help your organization develop and implement an effective Alarm Management plan. Contact us for more information.
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