Alarm management systems

When it comes to selecting an enterprise-wide alarm management system, businesses should consider the pros and cons of a third party specific alarm management tool over a DCS vendor’s offering.

By Jason Cook, Product Manager at MAC Solutions.

 Most process industries, particularly oil & gas, nuclear, utilities, power generation, pharmaceuticals, and Top Tier COMAH (Control of Major Accident Hazards) sites should view their alarm management system as a critical, integral part of their production or manufacturing facility. The UK’s Health & Safety Executive states “Alarm handling (or alarm management) is an issue for any site or process where there is claimed reliance on human response to an alarm in order to control major accident hazards.” And will use EEMUA 191 as its guidelines.

Since its establishment in 1991, EEMUA 191 has become the globally accepted standard for good practice alarm management. To establish an alarm management system based on these guidelines or to ascertain if a current system is operating effectively and within the guidelines, alarm data must be collected and analysed on a continuous basis. Just collecting this data can be a challenge in itself. Bringing this data into a usable format for Control Room Operators and reporting on this data to Alarm Managers are two critical functions.

There are many alarm management systems available on the market – some from third party, specific alarm management vendors such as ProcessVue from MAC Solutions, whilst other alarm management systems are offered as add-on modules by developers of Distributed Control Systems (DCS). Before committing to one particular vendor, users must consider the benefits of choosing a third party alarm management system over a DCS vendor’s offering.

Connectivity
Connectivity between the alarm management system, the DCS and other plant-wide safety systems such as Fire & Gas (F&G), Emergency Shutdown (ESD), Building Management Systems (BMS) and Metering (e.g. flow control meters, valves, etc.) is an important factor to consider. Whilst a DCS will only monitor alarms and events that the system itself generates, a specific third party alarm management tool is not restricted in this manner and provides full connectivity – and therefore a complete picture – of what is happening across all these plant-wide systems.

A third party alarm management system provides open connectivity between multiple, disparate plant safety systems, collecting alarm and event data from these systems and putting this information into a common format (language) and a single coherent message for Operators and other business users.

The software architecture should be designed to enable interfacing with almost any plant control system, bringing all data into a standard configurable format. This allows simple Operator SOE (Sequence of Event) display and high level KPI reporting and analysis. A good alarm management system should therefore provide features such as advanced KPI reporting based on EEMUA 191 guidelines; alarm rationalisation tools (locating ‘bad actors’ and ‘nuisance alarms’); Sequence of Event and real time display; alarm system benchmarking; alarm and event analysis; and alarm and event archiving.

No computing load on the DCS
The primary function of a DCS is to control the plant. Therefore, computing power should always take priority for this function. However, a DCS with an integrated alarm management module could become heavily loaded by multiple users requesting alarm and event KPIs, sucking valuable computing power away from the primary function of the DCS.

Easy access to data
Within process plants there are typically three network communications levels: the process control network; engineering network; and business network. For security purposes, it is considered good practice not to allow access to data more than one level up or down the networks. A DCS is typically located on the process control network and so providing access at the business level for managers becomes difficult or restricted at best. With a third party alarm management system, access and security is less of an issue as the system is not installed on the DCS, but can sit at any network level, typically at the engineering level, providing users with access to the sequence of events and KPI reports across the business as well as at plant control level.  

Store more data
Some plants require thousands of alarms to be monitored on a daily basis. The 100% reliability of a third party alarm management system ensures that data from all safety-critical plant is logged continuously, enabling engineers to identify the cause of a plant upset, including the SOEs leading up to this. A third party alarm management system therefore provides significantly more data than a DCS integrated alarm management system. The primary function of a DCS is plant control and so storage and computing power are used for that purpose, with alarm management often a secondary thought. A third party alarm management tool can provide years and years of alarm and event data without impacting on the DCS at all.

Easy to maintain
Third party alarm management systems are generally easier to maintain and keep up-to-date. The developer is more likely to keep the software bug-free and to provide more frequent software updates than a DCS vendor. This is important and ensures that the software is always based on the latest industry standards or best practice guidelines (e.g. EEMUA 191 Rev 3). With a DCS vendor’s alarm management add-on module, a DCS software upgrade may be required for what should be a relatively simple alarm management system update or bug fix.

Vendor commitment
Generally, a third party development house is more likely to be committed to their product, which is their lifeblood. This means the product will be more fully featured compared to a DCS vendor offering that is typically an afterthought or bolt-on module that performs the bare minimum and is designed to just ‘tick a box’.

More cost effective
With a third party alarm management system, typically the cost of a full installation is less than a DCS vendor alternative. Although the individual cost of the alarm management system may be well hidden within the total cost of the DCS package, the costs of any technical support and software maintenance for the alarm management system will need to be carefully considered. Typically, a third party developer will charge less than half that of a DCS vendor alternative.