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,…
Understanding operator decision-making is a good first step in improving operator effectiveness. Operator decision-making depends on the person (their level of expertise) and the situation (how familiar). A popular behavioral model from Rasmussen proposes that operator response can be broken into three levels; skill-based behavior, rule-based behavior, and knowledge-based behavior as shown in…
On July 27, the US Chemical Safety Board (CSB) issued a Factual Update on their investigation into a release of water containing a toxic gas (hydrogen sulfide) and subsequent fatal injuries sustained at the Aghorn Operating Waterflood Station. While it is typically not a good idea to comment on investigations…
Alarms were originally shown on Piping and Instrumentation Diagrams / Drawings (P&IDs) to document hardware requirements for installation in a (panelboard) control room. This was important because there was limited real estate in the control room for the alarms (displayed on Panalarms and light boxes) and there was a…
Recently I was reading The Manufacturing Operations Technology Viewpoints blog and came across an interest post on Alarm Management that cites exida’s Alarm Management cheat sheet. The blog post entitled The Crossroads of Alarm Management and Process Safety is a great summary for any one…
I recall the first time I was called an “expert.” I thought that sounded nice. I spotted a magazine article on safety and thought “I do not have to read that as I am an expert.” I quickly recovered. The real problem with being called an expert is that…
Hey everybody. I hope this blog finds you, your family, and your colleagues well. At exida, we appreciate the trust you place in our solutions and services to support you in achieving your functional safety, cybersecurity, and alarm management needs. We are committed…
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,…
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)…
We are going to continue discussing the results from exida’s recently published industry benchmark survey on the practices for the use of alarms as safeguards and IPLs. Over 200 safety practitioners from around the world provided responses. This entry will discuss the relationship between alarms identified as safeguards and…
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…
The alarm system is a daily encounter for most operations across different industries. For oil and gas, the alarm system alerts and reminds the operation to take action(s) to revert the process back to the normal operating range. For pharmaceuticals and batch operations, the alarm system can be used…
As many of you will know, one of the most common form of nuisance to operators working industrial controls are repeating or chattering alarms. On a typical plant, repeating alarms may account for around 50% of the alarm annunciations. They are a problem because the operator will have to…