The Importance of Assessing Alarm Performance

There is a direct connection between maintaining an effective alarm system and providing a safe working environment. With a requirement to prevent accidents and meet stringent industry regulations, it is important that alarm system performance is reviewed on an ongoing basis.

Within high hazard industries, a reliable alarm system is more than a convenience; it is a crucial protective layer, integral to the safety of operations, environmental stewardship and continuity of production.

An effective alarm system enables operators to respond swiftly and appropriately, averting incidents that could escalate into significant undesired events.

Ongoing assessment of alarm performance is therefore crucial, but what does this involve?

INTRODUCTION

An alarm system offers audible and visual notifications, alerting operators to process variables straying from normal levels, which could lead to undesirable safety, operational or environmental events.

By promptly addressing such deviations, the system aids in maintaining a safe, stable operation, thereby underpinning the site’s integrity.

As well as averting safety incidents, it is also important to consider that an alarm system also plays a substantive role in maintaining product quality, reducing equipment downtime and improving overall operational efficiency.

STANDARDS

Many industries require compliance with specific alarm management regulations, such as IEC 62682, EEMUA 191 and ISA18.2. These standards can be used to support the development of new alarm systems and the improvement of existing systems.

The standards provide guidance on the design and management of the alarm system, and include defined metrics to determine acceptable and manageable levels of alarms, aiming to ensure that alarms are prioritised and managed correctly.

This has the aim of avoiding ‘alarm floods’, which overwhelm and confuse operators, as well as minimising the potential for nuisance alarm which can desensitise operators leading to alarm fatigue.

Adherence to the standards in the design stage should minimise the risk of alarm flood and alarm fatigue occurring, however there are a number of challenges which can appear in an operational plant, including:

• The addition of alarms over time, noting that it is relatively easy to add alarms in modern alarm systems
• Variations in plant or process conditions
• Plant modifications leading to potential standing or redundant system alarms
• Ineffective or unclear alarm prioritisation

A robust Management of Change (MoC) process which adequately considers alarm system impact is an important requirement for any operator. It is also vital that actual alarm data is reviewed regularly in order to properly understand the performance and health of a system, and to ensure compliance with the acceptability and manageability limits defined in the alarm management standards.

ALARM PERFORMANCE LEVEL

Considering the information provided from the EEMUA 191 standard, there are defined metrics for manageable alarm levels, including:

• Alarm rate: The number of alarms per unit of time
• Alarm prioritisation and distribution: The distribution of alarm priorities
• Upset conditions: Alarm rates during upset conditions, including short-term manageable rates

Utilising these and other factors, it is possible to determine the Alarm System Performance Level, essentially the alarm system effectiveness with respect to operability.

To usefully compare an operating alarm system against the performance criteria from the standard, and hence determine the Alarm System Performance Level, performance data must be extracted from the alarm system. This extracted data can be used to support analysis of the alarm system health, for example, looking for alarm trends during different operational phases in order to identify recurring issues.

UTILISING ALARM DATA

Data extracted from an alarm system can often be difficult to interrogate in a meaningful way and can require interpretation and reformatting to allow useful conclusions to be drawn.

Dashboard tools are a useful means to take raw data from the alarm system as an input and present it in a consistent and clear manner which is easy to interpret.

TÜV Rheinland’s Alarm KPI is a tool which performs the function of taking this raw alarm data and displaying a breakdown of the alarm system performance and activity in a clear and concise form, removing the need for manual data manipulation and assessment.

A dashboard tool such as Alarm KPI can be always-on, producing a real-time picture of the health of the alarm system. An example in Figure 1 shows how the tool displays the most common alarms over a defined time period, as well as the alarm priority distribution (e.g. highest, high, medium and low). These and other results can instantly be automatically benchmarked against suggested metrics and Key Performance Indicators (KPIs) from the IEC 62682, EEMUA 191, and ISA 18.2 standards. This highlights any existing or emerging trends which threaten alarm performance or compliance in a timely manner, allowing appropriate action to be taken.

CONCLUSION

Ultimately, an industrial alarm system’s purpose is to facilitate prompt intervention to preserve the safety and health of workers and the environment.

Effective alarm performance monitoring and management on an ongoing basis provides the greatest opportunity to support informed decision-making and proactive incident prevention. It is not just best practice but a crucial investment in the sustainable success of industrial enterprises.

Utilising tools such as Alarm KPI therefore provides an effective and accessible means to support a proactive approach to alarm performance management

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