exida explains Blog

Which Measure (Rationalized or Annunciated) is More Important?

Which Measure (Rationalized or Annunciated) is More Important?

Get your priorities (distribution) straight

A very common question is posed during alarm management training.  Does the recommended alarm priority distribution of ~5% / ~15% / ~80% for high / medium / low priority alarms apply to the rationalized alarm priority distribution (as configured in the control system) or to the annunciatedalarm priority distribution…

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Bow Ties Part II: Do Bow Ties have a place in Alarm Management?

Bow Ties Part II: Do Bow Ties have a place in Alarm Management?

As discussed in Part I, bow tie diagrams provide an easy-to-understand visual representation of risk management information (hazards, potential consequences, barriers, degradation factors and controls). In this article we examine the applicability of bow ties to alarm management.

According to the CCPS book “Bow Ties in Risk Management”,…

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Alarm Philosophy Development – Going to Great Lengths

Alarm Philosophy Development – Going to Great Lengths

Creating an alarm philosophy document is often the entry point into the ISA-18.2/IEC 62682 alarm management lifecycle. Many tasked with developing one are discouraged by its length and the barriers it creates. When it comes to using the philosophy document, a common concern is that if the…

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Alarm Response Procedures: More than Just a Good Idea

Alarm Response Procedures: More than Just a Good Idea

From an operations point of view, one of the significant parts of the ISA-18.2 and IEC 62682 alarm management standards is the endorsement of alarm response procedures. An alarm response procedure, otherwise known as “Alarm Help” or “Alarm Response Manual”, is defined as guidance for response to an alarm (e.g., operator…

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CSB Cites Lack of Alarm Management as Contributing Factors to Blowout in Oklahoma

CSB Cites Lack of Alarm Management as Contributing Factors to Blowout in Oklahoma

Delivering Situation Awareness During an Alarm Flood: Throw Your Operators a Lifeline

Delivering Situation Awareness During an Alarm Flood: Throw Your Operators a Lifeline

Alarm floods are periods of alarm activity during which the alarm rate is greater than the operator can effectively manage (e.g., when the operator receives ≥10 alarms in 10 minutes). During a flood situation awareness is compromised and alarms are likely to be missed. In the eleven minutes prior to the explosion…

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Evaluating Alarm System Performance in a Multi-Operator Control Room

Evaluating Alarm System Performance in a Multi-Operator Control Room

Situation: There are three operator consoles (positions) in the same control room. There is one general alarm horn that goes off whenever a new alarm comes in from any one of the three consoles. The horn draws the attention of each of the three operators.

Question: How are the…

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When is an Alarm not an Alarm?

When is an Alarm not an Alarm?

The ISA-18.2 and IEC 62682 standards define an alarm as an “audible and/or visible means of indicating to the operator an equipment malfunction, process deviation, or abnormal condition requiring a timely response”.  One of the reasons why alarm systems are out of control (alarm overload, nuisance alarms)…

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Don’t Let Your Safe Operating Limits Leave You S-O-L (Out of Luck)

Don’t Let Your Safe Operating Limits Leave You S-O-L (Out of Luck)

As the name implies, the purpose of Safe Operating Limits (SOL) is to define the limits beyond which a process will not intentionally be operated and at which troubleshooting ceases, replaced by pre-determined actions to bring the process to a safe state. Pretty important information. I am sure this is…

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Bad Actor Knockdown: The “Whac-A-Mole” of Alarm Management?

Bad Actor Knockdown: The “Whac-A-Mole” of Alarm Management?

Alarm Shelving - Relieve the Symptoms of Nuisance Alarms and Create a Peaceful Control Room

Alarm Shelving - Relieve the Symptoms of Nuisance Alarms and Create a Peaceful Control Room

In an ideal world, every alarm in a process control system would indicate a malfunction or abnormal condition that required operator action. In the real world, alarms that are irrelevant or annunciate excessively—otherwise known as nuisance alarms—can pop up occasionally to quite frequently. They pose a risk to the…

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Human Factors in Alarm Management

Human Factors in Alarm Management

Question:

Which one of these layers of protection (operator response to alarm, relief valves, dikes, and safety instrumented systems) is not like the other? 

Answer:

Operator response to alarm (Operator Intervention), because of the “Human” factor.

It is very difficult to calculate the probability…

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Alarm Management and the Great American Solar Eclipse

Alarm Management and the Great American Solar Eclipse

Throughout history, total solar eclipses have been a significant event. In primitive societies, eclipses were viewed with fear or as important omens. In the US, the upcoming “Great American Solar Eclipse” is creating much excitement. From buying “official” eclipse-viewing glasses, to paying $1500 or more…

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What do Nuisance Alarms, the 80-20 Rule, Mental Models, and More Have in Common?

What do Nuisance Alarms, the 80-20 Rule, Mental Models, and More Have in Common?

Most everyone has heard of the “80-20 rule”.  It asserts that for many situations, roughly 80% of the effects (outcomes) come from 20% of the causes (inputs).  This rule was first proposed in the early 1900s by Vilfredo Pareto, who was an Italian engineer, sociologist, economist, political scientist, philosopher,…

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Nuisance Alarms and “The Boy Who Cried Wolf”

Nuisance Alarms and “The Boy Who Cried Wolf”

The purpose of an alarm is pretty straightforward - to draw the operator’s attention to an abnormal situation that requires action in order to prevent an undesired consequence. Alarms that don’t meet this principle often become nuisance alarms. A nuisance alarm is defined as:

“an alarm that annunciates excessively,…

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