Nuisance alarms are a symptom of poorly managed alarm systems, they inhibit the effectiveness of Operators and obscure the view of what is really going on – compromising safety and reducing the effectiveness of the alarm system. Yokogawa provides a comprehensive alarm reporting and analysis package which can typically reduce nuisance alarms by 80% and improve alarm system behaviour thus minimizing safety risks and enhancing plant operations.
Introduction
Alarm management is experiencing strong growth in the process industries, predominantly driven by the need to conform to standards and best practices such as ISA 18.2, EEMUA 191 and IEC 62682. Organizations are beginning to realise the significant benefits of investing in modern and more comprehensive alarm management solutions – from safety and economic gains plus improvements in environmental protection through more effective and smoother operational processes.
Causes of Nuisance Alarms
The alarm system is often the first line of defence to avoid serious process incidents. However poorly configured alarms, or those that have not received the appropriate attention and resources, often lead to alarm floods and nuisance alarms. Nuisance alarms or spurious alarms compromise safety and can inhibit the effectiveness of process operations for several reasons:
Obscurity of Alarm Information
Nuisance alarms obscure the Operator’s view of what is really going on. This is nearly always the case where alarm systems have not been properly managed and it is especially true during periods of process upset. Rob Turner, Yokogawa UK’s Principal Consultant for alarm management, commented:
“Whenever I ask Operators, they often tell me that during upsets they routinely abandon the alarm list altogether and rely instead on their experience and judgement because of the flood of alarm information they are presented with”.
This is a concern for many reasons, not least that the alarm system is of least use when it is needed most.
‘False’ Alarms
The second issue can be considered as a parallel of the story of the little boy who cried ‘Wolf!’. If the smoke detector went off in your kitchen, you would probably take it seriously and check for any signs of a problem. But what if the smoke detector went off repeatedly, because it was too sensitive or because it was in the wrong location, or even faulty? Would you still take it seriously after 3 activations? 5? 10 activations? Or would you remove the battery and ignore it? The equivalent is true for Operators in the control room who are presented with repeating nuisance alarms – they come to regard them as false, even if they are not. This is the process plant crying ‘Wolf!’
Operator Distraction
The third issue is that nuisance alarms distract the Operator from what they are doing. Imagine you are completing a mental task such as adding up a column of figures and someone repeatedly interrupts you. It is very likely you will forget how far you got, or even miss a figure out. It is also likely to become an irritation, and you may regard that someone a nuisance, even if they are trying to tell you something important. It is the same for Operators who are constantly distracted by nuisance alarms. Re-occurring nuisance alarms are given little or zero credibility by the Operators and are often ignored or disconnected.
Impacts of Nuisance Alarms
Operators who are subjected to alarm issues caused by alarm floods and nuisance alarms can become overwhelmed with alarm information and in some cases disregard it and rely on their instinct and experience. As a consequence, a poorly-managed alarm system dramatically increases the chances of safety incidents and unplanned downtime, resulting in financial loss, possibly environmental damage and in extreme cases, injury of personnel.
Time for a re-think of your Alarm System
Despite the drive towards regulatory compliance and the associated benefits, efficient and effective alarm management solutions continue to be a big issue in process plants due to a lack of continuous investment. Fortunately, there are several different approaches which organisations can adopt when it comes to rationalizing their alarm strategy to significantly reduce nuisance alarms. Re-thinking your alarm system can provide huge business benefits and improve the safety culture within a process plant. Find out how, by reading part 2 of this blog!
